text:
[email protected]
Add new document
Sign In
Create An Account
Evaluating the potential of superhydrophobic nanoporous alumina membranes for direct contact membrane distillation
Evaluating the potential of superhydrophobic nanoporous alumina membranes for direct contact membrane distillation
Evaluating the potential of superhydrophobic nanoporous alumina membranes for direct contact membrane distillation
Accepted Manuscript Evaluating the Potential of Superhydrophobic Nanoporous Alumina Membranes for Direct Contact Membrane Distillation Navaladian Subr...
Download PDF
3MB Sizes
0 Downloads
5 Views
Recommend Documents
polydimethylsiloxane electrospun nanofibrous membranes for water desalination by direct contact membrane distillation
Fabrication and characterization of superhydrophobic poly (vinylidene fluoride) membrane for direct contact membrane distillation
Superhydrophobic nanofiber membrane containing carbon nanotubes for high-performance direct contact membrane distillation
Anisotropic performance of a superhydrophobic polyvinyl difluoride membrane with corrugated pattern in direct contact membrane distillation
Seawater desalination by direct contact membrane distillation
Laminated PTFE membranes to enhance the performance in direct contact membrane distillation for high salinity solution
Nanoporous alumina membranes
Surface treatment of polyethersulfone membranes for applying in desalination by direct contact membrane distillation
Preparation and properties of PVDF composite hollow fiber membranes for desalination through direct contact membrane distillation
Fabrication of polyvinylidene fluoride (PVDF) nanofiber membranes by electro-spinning for direct contact membrane distillation
PDF Reader
Full Text
Accepted Manuscript Evaluating the Potential of Superhydrophobic Nanoporous Alumina Membranes for Direct Contact Membrane Distillation Navaladian Subramanian, Adnan Qamar, Ahmad Alsaadi, Adair Gallo Jr., Muhammed Ghifari, Jung-Gil Lee, Sreekiran Pillai, Sankara Arunachalam, Dalaver Anjum, Felix Sharipov, Noreddine Ghaffour, Himanshu Mishra PII: DOI: Reference:
S0021-9797(18)30970-6 https://doi.org/10.1016/j.jcis.2018.08.054 YJCIS 23987
To appear in:
Journal of Colloid and Interface Science
Received Date: Revised Date: Accepted Date:
29 March 2018 19 August 2018 20 August 2018
Please cite this article as: N. Subramanian, A. Qamar, A. Alsaadi, A. Gallo Jr., M. Ghifari, J-G. Lee, S. Pillai, S. Arunachalam, D. Anjum, F. Sharipov, N. Ghaffour, H. Mishra, Evaluating the Potential of Superhydrophobic Nanoporous Alumina Membranes for Direct Contact Membrane Distillation, Journal of Colloid and Interface Science (2018), doi: https://doi.org/10.1016/j.jcis.2018.08.054
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Evaluating the Potential of Superhydrophobic Nanoporous Alumina Membranes for Direct Contact Membrane Distillation
Navaladian Subramanian1§, Adnan Qamar1§, Ahmad Alsaadi1, Adair Gallo Jr.1, Muhammed Ghifari1,2, Jung-Gil Lee1, Sreekiran Pillai1, Sankara Arunachalam1, Dalaver Anjum3, Felix Sharipov4, Noreddine Ghaffour1, Himanshu Mishra1* 1
King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center
(WDRC), Biological and Environmental Science & Engineering Division (BESE), Thuwal, 23955-6900, Saudi Arabia 2
Visiting from Institut Teknologi, Bandung, Bandung (40132) Indonesia
King Abdullah University of Science and Technology (KAUST), Core Laboratory, Thuwal, 23955-6900, Saudi Arabia
Departamento de Fisica, Universidade Federal do Parana, Caixa Postal 19044, Curitiba 81531-990, Brazil §
Equal contribution
[email protected]
Keywords: superhydrophobicity; ceramic membranes; thermal conductivity; hydrodynamics; membrane distillation; temperature polarization
Abstract Hypothesis: Direct contact membrane distillation (DCMD) processes exploit water-repellant membranes to desalt warm seawaters by allowing only water vapor to transport across. While perfluorinated membranes/coatings are routinely used for DCMD, their vulnerability to abrasion, heat, and harsh chemicals necessitates alternatives, such as ceramics. Herein, we systematically assess the potential of ceramic membranes consisting of anodized aluminum oxide (AAO) for DCMD. Experiments: We rendered AAO membranes superhydrophobic to accomplish the separation of hot salty water (343 K, 0.7 M NaCl) and cold deionized water (292 K) and quantified vapor transport. We also developed a multiscale model based on computational fluid dynamics, conjugate heat transfer, and the kinetic theory of gases to gain insights into our experiments. Findings: The average vapor fluxes, J, across three sets of AAO membranes with average nanochannel diameters (and porosities) centered at 80 nm (32%), 100 nm (37%), and 160 nm (57%) varied by < 25%, while we had expected them to scale with the porosities. Our multiscale simulations unveiled how the high thermal conductivity of the AAO membranes reduced the effective temperature drive for the mass transfer. Our results highlight the limitations of AAO membranes for DCMD and might advance the rational development of desalination membranes.
1. INTRODUCTION Mass transfer of water vapor across porous media regulates the behavior of numerous natural and applied systems including soils1-2, transpiration2-3, crushed ores, food processing4, leaks and cracks in construction5-7, electronic packaging6, membrane extractions of water vapor8 and other chemicals9, and micro- and nano-fluidics10-17. Of those systems, we are interested in extracting desalted water from the oceans through membrane distillation (MD), wherein water vapor from hot salty streams is transferred through porous hydrophobic membranes to condense on the other side9, 18-21. If the other side comprises a stream of cold deionized water, the process is known as the direct contact membrane distillation (DCMD; Figure 1); or if the other side comprises air at low pressure, the process is known as the air gap MD22. In comparison to reverse osmosis (RO), an energy intensive yet common desalination technique23, MD processes can be designed with lower carbon footprint because the latter can utilize low-grade waste heat from industrial and natural sources, such as low-enthalpy geothermal or solar-thermal20, 24
. However, fluxes from the MD-based-approaches have been limiting in comparison to
RO, prompting research in innovating approaches towards novel materials and processes. The flux of desalted water and energy efficiency in DCMD process crucially depend on the thermal gradients across the membranes; other membrane characteristics, including the hydrophobicity, porosity, thermal and chemical stability, and resistance to biofouling determine the long-term functionality19-22, 25-26. Thus, ideal membranes should be water-repellent, bad conductor of heat, mechanically robust, and inert to chemical and biological fouling. To this end, a variety of materials have been explored for scalability, efficiency, and durability, including polytetrafluoroethylene (PTFE)26, polyvinylidene fluoride (PVDF)27, graphene oxide28, carbon nanotubes8, buckypapers29, and organosilica infused PVDF30. In fact, commercial MD membranes extensively exploit PTFE, which offers excellent thermal, chemical, and hydrophobic characteristics25-26. However, PTFE has poor mechanical properties and researchers have explored the addition of fillers comprising alumina and titania to boost the durability, strength, and abrasion resistance31. Porous ceramic membranes have also been investigated for MD20,
25, 32-34
. In fact,
anodized aluminum oxide (AAO) membranes are of particular interest as they provide (i) a light, lithography-free platform comprising vertically-aligned nanochannels of tunable
diameters with ultrahigh packing densities (
channels-m-2), (ii) ease of surface
modification35, and (iii) amenability to theoretical modeling due to their geometrical simplicity to gain insights into mass transport4, 6. For instance, AAO membranes with nanochannels of diameters ranging from 10-120 nm were used to investigate the transport of water (vapor and liquid)4, 6 and noble gases36 at 295 K and 1 atm and compared with continuum models for mass transport; others deposited amorphous carbon37-38 onto AAO membranes by chemical vapor deposition to render them hydrophobic and observed 45times higher mass transfer of liquid water in comparison to the predictions of the HagenPoiseuille theory of Newtonian liquids and ascribed it to the hydrodynamic slip at waterhydrophobe interfaces37. Recently, researchers have employed silanation reactions to hydrophobize AAO membranes and investigated osmotic mass transfer of water vapor under isothermal conditions10 and thermal gradients32. While the focus of most of those approaches has been on the surface functionalization of AAO membranes, effects of their thermal conductivity on mass transfer in DCMD are not entirely clear. In fact, a known sink for the energy efficiency in DCMD is the drop in the temperatures between the liquid-vapor interfaces and the bulk liquids due to the formation of thermal boundary layers—also known as temperature polarization20. Indeed, temperature polarization is primarily influenced by the thermal conductivity of membranes. For instance, thermal conductivities of commercial PVDF/PTFE membranes range within 0.04-0.08 W-m-1-K-1 and researchers have simulated the effects of temperature polarization by incorporating extant experimental correlations of Nusselt numbers across a wide range of flow conditions20, 39-45. However, for AAO and other ceramic membranes, such experimental data do not exist preventing clear insights into mass transport. To clarify this matter, we present experimental results on the mass transport of water vapor across nanoporous AAO membranes in DCMD along with a multiscale theoretical model explaining our observations.
Figure 1. Schematic of a typical direct contact membrane distillation (DCMD) setup - a hydrophobic membrane separates a salty stream (hot) of water from a deionized (cold) stream, flowing in opposite directions. Only water vapor transports across from the hot to the cold side.
2. MATERIALS CHARACTERIZATION We investigated three types of coin-shaped AAO membranes (Synkera Tech., USA) with average nanochannel diameters, D, centered at 80 nm, 100 nm, and 160 nm (Figure 2, S1-3), with the macroscopic diameter of 2.5 cm and thickness, ≈100 μm. Their porosities, defined as the fraction of the entrapped air to the membrane volume, were 32% (80 nm), 37% (100 nm), and 57% (160 nm), respectively. The surface density of holes on the top sides of the membranes were similar across the membranes, whereas the numbers on the undersides varied in the ratio
(Table 1). The
variation in the surface density of pores on the underside was due to branching of some nanochannels (Figure 2D3-D4). The as-received membranes were unfit for DCMD due to their hydrophilicity - the advancing and receding contact angles of deionized water under normal temperature and pressure (NTP: 293.15 K, 1 atm) conditions on smooth and flat alumina in air were
, respectively, and when drops of water were
placed on as-received AAO membranes, they spontaneously imbibed into the nanochannels underneath, as observed by others46-48 (Figure 3A). Further, those membranes exhibited mechanical fragility and chemical reactivity towards hot water. To overcome those challenges, we annealed the AAO membranes in air in a muffle furnace to render them polycrystalline. During annealing, the temperature was ramped from the room temperature to 773 K at 10 K-min-1, from 773 to 923 K at 5 K-min-1, and from 923
to 1273 K at 2 K-min-1; subsequently, the dwell time at 1273 K was 2 h. After annealing, cooling was performed at 2 K-min-1 from 1273 K to 873 K, and at 5 K-min-1 until 303 K. To prevent the bending and buckling of the membranes during annealing, they were sandwiched between smooth alumina plates of 1.5 mm thickness and a ceramic plate of mass 0.3 kg was placed on top. The resulting membranes were polycrystalline, primarily comprising γ- and δ-alumina phases10, and exhibited mechanical and chemical robustness, though with higher surface roughness (Figure 2).
Figure 2. (A-C) Representative scanning electron micrographs of the top and bottom sides of pristine and annealed AAO membranes with an average channel diameter of 80 nm (A1-A4), 100 nm (B1-B4), and 160 nm (C1-C4) respectively, demonstrating that annealing at 1273 K for 2 h in air did not lead to physical damage. (D) Representative cross-sectional TEM images of the asreceived AAO films of average channel diameter, . After the heat-treatment, crystalline grains and pits appeared on the AAO nanochannels, which increased their roughness. Channels are characterized by the darker contrast in the images.
The selected area electron diffraction (SAED) patterns of the as-received AAO membranes, observed during transmission electron microscopy, comprised a single broad ring confirming the amorphous phase (Figure 3A-C). On the other hand, the heat-treated AAO membranes exhibited spot and ring patterns in the SAED patterns and lattice fringes in the TEM images, confirming the polycrystallinity (Figure 3B-D).
Figure 3. High magnification TEM images of pristine (A and C); and annealed AAO membranes (B and D) of average channel diameter D = 80 nm. Insets in images (A) and (D) are SAED patterns collected on the respective AAO membranes.
We further confirmed those observations with x-ray diffraction (XRD) - the XRD patterns of the pristine AAO membranes showed broad humps centered at the 2 values 28 and 64, implying that the as-received AAO membranes were amorphous (Figure 4A-C). In contrast, the XRD patterns from the heat-treated (annealed) AAO membranes showed diffraction peaks corresponding to - and -alumina (JCPDS files numbers 00010-0425 and 00-046-1131, respectively) (Figure 4A-C).49 No noteworthy differences between the top and bottom sides of the AAO membranes were observed.
Figure 4. XRD patterns of pristine, annealed, and FDTS-coated AAO membranes with average nanochannel diameters of (A) 80 nm, (B) 100 nm, and (C) 160 nm. Patterns (a) and (b) correspond to the top and bottom sides of pristine AAO membranes, patterns (c) and (d) correspond to the top and bottom sides of annealed AAO membranes, and patterns (e) and (f) correspond to the top and bottom sides of FDTS-coate O e br es. Sy bols 'δ' 'γ' i the graphs indicate the phases of Al2O3.
Subsequently, to render the alumina surface hydrophobic, characterized by apparent
angles of water in
90, we chemically grafted
perfluorodecyltrichlorosilane (FDTS) molecules onto alumina through a molecular vapor deposition technique (Figure 5, SI Section S2). The absence of any extra peak in the XRD pattern of the FDTS-coated AAO membranes, in comparison to annealed AAO, confirmed that no solid impurity was introduced. Due to the combination of surface chemistry and nanoscale roughness, the resulting FDTS-coated annealed AAO membranes exhibited superhydrophobicity, characterized by advancing and receding contact angles of water droplets in air
(Table 1) The contact angles
were measured using the Kruss Drop Shape Analyzer (DSA100) interfaced with the Advance software; sessile drops of volume 4 L were deposited onto several locations on the membranes at the rate of 0.2 L/s and contact angles were estimated by fitting tangents at the solid-liquid-vapor interface as well as fitting circles to the shape of drops. FDTS-coated AAO membranes repelled water drops falling from a height of ~1cm (Figure 5).
Table 1. The summary of contact angles of water on all the AAO membranes investigated in this work before and after silanation with FDTS. (Section S3 explains image analysis employed to obtain surface pore densities listed below)
Surface treatments of AAO membranes
Apparent contact angles, , for deionized water Top
80 nm (annealed)
80 nm (FDTS)
100 nm (pristine)
100 nm (annealed)
100 nm (FDTS)
160 nm (pristine)
160 nm (annealed)
160 nm (FDTS)
80 nm (pristine)
Topside pores
Underside pores
Dia (nm) (± std. dev.)
Pore density (#/m2) ×1013
Dia (nm) (± std. dev.)
Pore density (#/m2) ×1013
77 ± 18
65 ± 22
97 ± 19
91 ± 26
176 ± 33
185 ± 34
We estimated the maximum pressure that our superhydrophobic membranes could withstand against water infiltration, also known as the liquid entry pressure or the breakthrough pressure, as
, where γ = 72 mN/m is the surface tension
of the water at the normal temperature and pressure (NTP: 293 K, 1 atm),
is the
intrinsic contact angle of water on a smooth surface of identical chemical composition as the membrane, and
is the radius of the channel (Figure 5A-B)50. For example, for the
FDTS-coated AAO membranes with D = 80 nm, the liquid entry pressure was atm, which ensured that liquid water would not penetrate them under the mild application of pressure in our DCMD experiments; only water vapor would. Therefore, we considered our membranes to be suitable for the investigation of mass transfer of water vapor in the DCMD configuration (Figure 1).
Liquid water
PL = 2γLV/r = 4γLVcosθo/D
Liquid water
θo≈110° θ o
θo≈ 20°
Porous Anodic Alumina (PAA) D=80 nm Air
r α = 180° - θ o
FDTS-coated porous anodic D = 80 nm alumina (PAA)
Water imbibes spontaneously displacing air
Maximum Laplace Pressure,
Liquid water can not penetrate. Only vapor transport allowed.
Figure 5. (A) A schematic of liquid water penetrating a superhydrophilic anodized aluminum oxide (AAO) membrane, driven by the curvature of the liquid (the intrinsic angle of the air-water system, o ). (B) AAO membranes with covalently grafted perfluorodecyltrichlorosilane (FDTS) molecules. The intrinsic angle of the air-water system on smooth alumina increased to , and the membrane exhibited superhydrophobicity. If water was forced inward, the o curvature of the air-water interface prevented intrusion (shown by dotted lines); the maximum pressure, known as the liquid entry pressure, γ , where γ = 72 mN/m and other variables are shown. (C) A ball and stick representation of a perfluorodecyltrichlorosilane molecule with gray, light-green, purple and dark-green balls representing carbon, fluorine, silicon and chlorine atoms, respectively. (D) A representative high-speed image sequence of a water droplet bouncing on a superhydrophobic AAO membrane with nanochannels of average diameter D = 80 nm.
3. EXPERIMENTAL SETUP We used a custom-built DCMD module8 to measure the flux of water vapor across our superhydrophobic AAO membranes (Figure 6). The membranes separated a hot stream of water from the Red Sea (~0.7 M NaCl) at 343 K (which we refer to as the feed side), from a cold stream of deionized water at 292 K (the permeate side). The feedand permeate flows were opposite in direction and maintained at 100 ml/min (~0.2 m/s). The undersides of the membranes were in contact with the feed side (Figure 2, Table 1). The flux of the water vapor from the feed to the permeate was measured by monitoring the increasing mass of the latter over time using a precision balance (resolution: 0.01 g).
Figure 6. (A) Schematic of direct contact membrane distillation (DCMD) setup used to quantify the flux of water vapor transported across superhydrophobic AAO membranes. (B) Photograph of the module with FDTS-coated AAO membrane installed in the DCMD setup. Inside the module, a polydimethylsiloxane (PDMS) o-ring prevents mechanical damage to the membrane
4. RESULTS AND DISCUSSION: Under our experimental conditions, the volumetric flux of the AAO membranes of average nanochannel diameters 80 nm, 100 nm, and 160 nm ranged within .
DCMD process was
over a span of 20 hrs of operation. The salt rejection rate in the 99.9%, measured through the electrical conductivity of the
permeate solutions. Contrary to our expectation, the fluxes did not scale with the porosities of the membranes – while the porosities, ξ, varied by ~80% across our membranes, the flux, J, varied only by < 25%. To understand the mass transport at the pore-scale, we exploited the simple geometry of our AAO membranes (Table 1) and converted the membrane fluxes into the rate of transport of water molecules passing through the inlets to the nanochannels as, .
s- ,
s- , and
s-1. To gain insight into the factors controlling the mass transport, including
membrane porosity, thermal conductivity, fluid dynamics, and heat and mass transfer, a new multiscale simulation framework was implemented.
4.1 Multiscale Model The predictive power of models based on the kinetic theory of gases51, the Navier-Stokes equation52, and the Boltzmann equation53 has been realized4, 54. Since liquid water did not penetrate into our superhydrophobic AAO membranes, we could quantify heat transfer across them by approximating them as rigid solids sandwiched between the feed and permeate (Figure 7). To capture the steady-state temperature profiles, we employed computational fluid dynamics (CFD) coupled with conjugate heat transfer. Considering the steady-state temperatures and latent heat of the feed, vapor fluxes were estimated using the kinetic theory of gases. This multiscale approach captured our experimental conditions and results within reasonable accuracy. Below, we introduce the modeling approach in the following three sub-sections:
4.1.1 Pore Flow We estimated the mass transfer of water vapor through vertically-aligned pores of our AAO membranes by assuming it to be an ideal gas55-56. For an ideal gas diffusing across a channel of macroscopic dimensions, the number of molecular collisions with the walls is insignificant in comparison to the collisions between the gas molecules and their effects can be ignored. However, as the size of the channel, D, becomes comparable to the average distance traveled by the gas molecules between successive collisions, also known as the mean free path, the collisions with the walls become important. The mean free path of an ideal gas is given by,
, where P, T, and d are the pressure,
temperature, and molecular size of the gas55. The gas rarefaction can be described by the Knudsen number defined as
. Thus, based on the Knudsen number, Kn, flows
inside channels are classified into three regimes: (i) continuous or hydrodynamic flow .
), where the frequency of gas-gas collisions is much higher than frequency of
gas-surface collision, (ii) transitional flow ( .
), where the frequency of
collisions with the walls is similar to the gas-gas collisions, and (iii) free-molecular or Knudsen flow ( 56
), where collisions with the walls dominate the diffusion rates4, 55-
. We estimated the mean free path of water vapor under our experimental conditions to
nm that was commensurate with the average diameter of the nanochannels in
our membranes. Thus, the mass transfers through our AAO membranes were governed by the transitional (or interdiffusive) range, where the collisions of water vapor with both channel walls and gas molecules should be considered. Under such conditions, the mass flux, J, is related to the molar flow rate,
, as57-58
(1a) ,
(1c) ,
where DII is the intermediate interdiffusive constant, DKI is the Knudsen diffusion constant (considering collisions with the
wall), DCI is the classical interdiffusive
constant (considering collisions between gas molecules), rc is the radius of the channel, P is the vapor pressure difference at the edges of the nanochannels in contact with the feed and permeate respectively, Ro is the universal gas constant, Tm is the mean temperature at the two ends of channel (317.5 K)59, L is the channel length, kB is the Boltzmann constant, m is the molecular mass, dm1 and dm2 are the molecular diameters of the two components (water vapor and N2), dm is the mean molecular diameter of the interdiffusive gas, and PT is the pressure inside the nanochannel.
4.1.2 Conjugate Heat Transfer Assuming the feed and permeate to be incompressible, we used the following governing equations to simulate heat transfer at solid-liquid interfaces60: Mass Conservation: (2) Momentum Conservation: -
Energy Conservation: .
represented the velocity vector, P was the hydrodynamic pressure,
stress tensor,
was the
represented the acceleration due to gravity, E was the total energy, K was
the liquid thermal conductivity, and
were the fluid density and viscosity. The stress
tensor and total energy were estimated as, (5) -
where h was the sensible enthalpy represented by (7) Under our experimental conditions the flows were laminar (~0.2 m/s), so we ignored the effects of turbulence in our model. Subsequently, heat transfer through the solid AAO membrane was simulated by the following energy equation: .
where km was the thermal conductivity of the AAO membrane. We approximated the heat transfer from the hot to the cold sides to comprise heat conduction and the latent heat of evaporation at the feed-side as: (9) where km was the thermal conductivity of the AAO membrane, J was the vapor flux (Eq. 1a), and
was the latent heat of vaporization of seawater (2258 kJ/kg). The
contributions of conduction and latent heats, the first and second terms in equation (9), were estimated by equations (2-8) and a boundary condition on the feed-side respectively. The thermal conductivity of the AAO membranes, km, was estimated as a function of porosity, ξ (percentage), based on the empirical relationship developed by Abad and co-workers61 using a photoacoustic technique, as km= 1.32 - 0.01×ξ
As the porosity of the membranes increased from 32% to 35% and 57% for membranes with average nanochannel diameters 80 nm, 100 nm, and 160 nm, the thermal conductivities were estimated to be 1.0 W-m-1-K-1, 0.95 W-m-1-K-1, and 0.75 W-m-1-K-1, respectively.
Membrane Thickness, δ
AAO Membrane Cross-sectio
Figure 7. Schematic of an AAO membrane with the feed-side (Red Sea water ~0.7 M NaCl at 343 K at 100 ml/min) and permeate-side (deionized water at 292 K) streams flowing in opposite directions on either side. Thermophysical properties of the feed and permeate are also listed: U denotes the flow speed, T is the temperature, is the density, is the viscosity, and is the surface tension.62
4.1.3 Multiscale Coupling The coupling between the feed, permeate, and vapor transport was simulated by solving equations Eq. 1-9. At each time-step, the numerical framework (Eq. 2-8) yielded distributions of temperature and flow-velocity and hydrodynamic pressure in the simulation box (Figures 6B, 7, 8). Temperature-dependent vapor pressures at the feedand permeate-side were estimated through the empirical Antoine equation63-65. Based on the pressure difference across the membrane pores, P, vapor flux, J, was computed at each time step (Eq. 1a) and the updated value of flux was passed to the conservation equations solver through Eq. 9. This procedure was repeated until the steady state was reached using the ANSY-Fluent software (Version 17.2) using a second-order time and space control volume discretization.
4.2 Theoretical Predictions:
Using the above-mentioned multiscale framework, we simulated the steady-state hydrodynamic (gauge) pressures, liquid velocity contours, and temperature distributions in the feed-membrane-permeate system subjected to our experimental conditions. The model confirmed that the hydrodynamic pressure drops along the superhydrophobic membrane surface were negligible (Figure 8A), perhaps due to the entrapment of air at the solid-liquid interface rendering slippage12, 17, 66. The velocity profiles were symmetric on either side with minor flow constriction effects at the inlets (Figure 8B). The temperature profiles across the membranes were found to be linear (Figures 8C-D).
Figure 8. Representative predicted spatial contours for AAO membranes (D = 100 nm, ≈ 100 μ ) separating the feed and permeate flows under our experimental conditions. (A) Hydrodynamic pressure distribution; (B) Fluid velocity distribution; (C) Temerature distribution; (D) Zoom-in view of the temperature distribution. Most notably, we found that the temperature differences of the air-water interfaces at the feed and permeate sides of the membrane pores of diameters 80 nm, 100 nm, and 160 nm were 37%, 38%, and 46% lower respectively, in comparison to the difference in the temperatures of the bulk streams (Figure 9A). As a result of this temperature polarization, the vapor fluxes across the AAO membranes did not vary proportionally with the
porosity, as would have been the case if the interfacial temperature profiles were the same (Eq. 1A).
Figure 9. (A) Thermal boundary layer profiles for AAO membranes with average nanochannel diameters, D, 80 nm, 100 nm, and 160 nm under cross-flow configuration. The feed-side comprised water from the Red Sea (~0.7 M NaCl) at 343 K and the permeate side comprised of deionized water at 292 K, both flowing at 0.2 m/s, in opposite directions. (B) Temperature profiles along the whole lateral dimension of the AAO membrane with nanochannel diameter, D =100 nm.
Our multiscale model predicted the pore-level fluxes across the nanochannels of diameters 100 nm and 160 nm to be 4% and 23% higher than that through the 80 nm channels respectively, which was in agreement with the experimental results (Figure 10). The simulated lateral temperature distributions are presented in Figure 9B. The model also predicted that the mass transport could be enhanced by reducing the thermal conductivity (Figures S4-5) and increasing the feed-side temperature (Figure S6).
Figure 10. Experimental (red) and simulated (blue) flow rates of water vapor across hydrophobic nanochannels of AAO membranes with average channel diameters 80 nm, 100 nm, and 160 nm. Theoretical predictions without considering temperature polarization across membranes are presented as green circles. Lines have been drawn to facilitate viewing. 17
Below, we briefly discuss potential sources of error in our predictions due to the lack of consideration of concentration polarization, capillary condensation, gas-mixtures, and multiphase flows. Due to the evaporation of water at the feed-side, the salt concentration rises affecting the vapor pressure, known as concentration polarization22, but these effects were not considered in our model. Capillary condensation of water inside nanochannels leading to water plugs is also possible4, 6, 48, 67-68, but assumed to be negligible in this work. The application of the kinetic theory of gases to simulate mixtures of real gases in confinement could also lead to errors and researchers have proposed more rigorous methods55, 69, which were not considered here. We also note that multiphase simulations explicitly considering membrane porosity could yield more accurate description of the physics4, 70 also falls beyond the scope of this work.
5. Conclusion and Outlook: We investigated the mass transport of water vapor across nanoporous ceramic membranes composed of AAO for potential application in DCMD, a low carbon footprint technology for desalination. While ceramic membranes could offer superior abrasionresistance in comparison to the PTFE counterparts in DCMD, the influence of their thermal conductivity on the vapor transport has not been entirely clear. In response, we compared the performance of AAO membranes comprising vertically aligned nanochannels with average diameters centered at 80 nm, 100 nm, and 160 nm. To render the membranes suitable for DCMD, we annealed them at 1273 K for 2 hrs, followed by chemically grafting hydrophobic coatings onto them. The efficacy of the resulting superhydrophobic AAO membranes for DCMD was evaluated through a custom-built set up, where the membranes separated counter-flowing streams (0.2 m/s) of hot salty water (343 K, 0.7 M NaCl) and cold deionized water (292 K). Interestingly, we found that the difference in the fluxes of vapor across the membranes comprising of nanochannels of average diameters 80 nm and 160 nm was 25%, .
, whereas we
expected a doubling in proportion to the porosities. To understand the factors and mechanisms underlying this observation, we employed a multiscale model based on computational fluid dynamics and kinetic theory of gases to predict fluxes across those membranes while capturing the hydrodynamics and heat transfer in our experiments. Our 18
simulations demonstrated that the high thermal conductivity of the AAO ceramic membranes led to severe temperature polarization, such that the temperature differences between the apposing air-water interfaces inside the nanochannels, driving the mass transport, were significantly lower than that of the bulk liquids. Specifically, the temperature differences between the liquid-vapor interfaces under our experimental conditions were predicted to be 37%, 38%, and 46% lower for the AAO nanochannels of diameters 80 nm, 100 nm, and 160 nm respectively. The pore-level predictions of flux of water vapor were in reasonable agreement with our experimental results. Thus, our report explains the mechanisms and factors underlying the limited scope of AAO membranes for DCMD, as suggested by others32. To compare with typical PVDF, PTFE, and polypropylene membranes employed in DCMD, with cumulative thermal conductivities, km ≈ 0.07 Wm-1K-1, considering the polymer conductivity, km ≈ 0.26 Wm-1K-1 and 80% porosity19, 26, the thermal conductivities of typical AAO membranes are nearly an order of magnitude higher. Thus, for AAO membranes to be employed in DCMD, strategies for lowering the thermal conductivity should be explored. For instance, it might be worth exploring thermally insulating materials to coat AAO membranes, without clogging the nanochannels, before rendering them superhydrophobic71. New approaches in designing thermoelectric materials, where the reduction of thermal conductivity is also crucial, might be insightful72-74. Alternatively, superhydrophobic AAO membranes should be tested in the air gap MD and vacuum MD configurations that are less vulnerable to temperature polarization75. This work might advance the rational design of materials and processes for DCMD and thermally driven liquid-vapor extraction, in general.
Acknowledgements The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST). The authors thank Mr. Ivan Gromicho, Scientific Illustrator at KAUST, for preparing Figure 1.
1. Hillel, D., Introduction to Soil Physics. Academic Press: 1982. 2. Fisher, J. B.; Melton, F.; Middleton, E.; Hain, C.; Anderson, M.; Allen, R.; McCabe, M. F.; Hook, S.; Baldocchi, D.; Townsend, P. A.; Kilic, A.; Tu, K.; Miralles, D. D.; Perret, J.; Lagouarde, J. P.; Waliser, D.; Purdy, A. J.; French, A.; Schimel, D.; Famiglietti, J. S.; Stephens, G.; Wood, E. F., The future of evapotranspiration: Global requirements for ecosystem functioning, carbon and climate feedbacks, agricultural management, and water resources. Water Resour Res 2017, 53 (4), 2618-2626. 3. Evaristo, J.; Jasechko, S.; McDonnell, J. J., Global separation of plant transpiration from groundwater and streamflow. Nature 2015, 525 (7567), 91-94. 4. Wenwen, L.; Rigozzi, M. K.; McKenzie, D. R., The physics of confined flow and its application to water leaks, water permeation and water nanoflows: a review. Reports on Progress in Physics 2016, 79 (2), 025901. 5. Luping, T.; Nilsson, L.-O., A study of the quantitative relationship between permeability and pore size distribution of hardened cement pastes. Cement and Concrete Research 1992, 22 (4), 541-550. 6. Lei, W.; McKenzie, D. R., Nanoscale Capillary Flows in Alumina: Testing the Limits of Classical Theory. The Journal of Physical Chemistry Letters 2016, 7 (14), 2647-2652. 7. Mignon, A.; Snoeck, D.; Dubruel, P.; Van Vlierberghe, S.; De Belie, N., Crack Mitigation in Concrete: Superabsorbent Polymers as Key to Success? Materials 2017, 10 (3), 237. 8. An, A. K.; Lee, E. J.; Guo, J. X.; Jeong, S.; Lee, J. G.; Ghaffour, N., Enhanced vapor transport in membrane distillation via functionalized carbon nanotubes anchored into electrospun nanofibres. Sci Rep-Uk 2017, 7. 9. Chen, J.; Razdan, N.; Field, T.; Liu, D. E.; Wolski, P.; Cao X.; Prausnitz J. M.; Radke, C. J., Recovery of dilute aqueous butanol by membrane vapor extraction with dodecane or mesitylene. J Membrane Sci 2017, 528, 103-111. 10. Lee, J.; Laoui, T.; Karnik, R., Nanofluidic transport governed by the liquid/vapour interface. Nat Nano 2014, 9 (4), 317-323. 11. Domingues, E. M.; Arunachalam, S.; Mishra, H., Doubly Reentrant Cavities Prevent Catastrophic Wetting Transitions on Intrinsically Wetting Surfaces. ACS Applied Materials & Interfaces 2017, 9 (25), 21532-21538. 12. Mishra, H.; Schrader, A. M.; Lee, D. W.; Gallo, A.; Chen, S. Y.; Kaufman, Y.; Das, S.; Israelachvili, J. N., Time-Dependent Wetting Behavior of PDMS Surfaces with Bioinspired, Hierarchical Structures. ACS Applied Materials & Interfaces 2016, 8 (12), 8168-8174. 13. Remsing, R. C.; Xi, E.; Vembanur, S.; Sharma, S.; Debenedetti, P. G.; Garde, S.; Patel, A. J., Pathways to dewetting in hydrophobic confinement. P Natl Acad Sci USA 2015, 112 (27), 8181-8186. 14. Kidambi, P. R.; Boutilier, M. S. H.; Wang, L. D.; Jang, D.; Kim, J.; Karnik, R., Selective Nanoscale Mass Transport across Atomically Thin Single Crystalline Graphene Membranes. Adv Mater 2017, 29 (19). 15. Radha, B.; Esfandiar, A.; Wang, F. C.; Rooney, A. P.; Gopinadhan, K.; Keerthi, A.; Mishchenko, A.; Janardanan, A.; Blake, P.; Fumagalli, L.; Lozada-Hidalgo, M.; Garaj, S.;
Haigh, S. J.; Grigorieva, I. V.; Wu, H. A.; Geim, A. K., Molecular transport through capillaries made with atomic-scale precision. Nature 2016, 538, 222. 16. Esfandiar, A.; Radha, B.; Wang, F. C.; Yang, Q.; Hu, S.; Garaj, S.; Nair, R. R.; Geim, A. K.; Gopinadhan, K., Size effect in ion transport through angstrom-scale slits. Science 2017, 358 (6362), 511-513. 17. Domingues, E. M.; Arunachalam, S.; Nauruzbayeva, J.; Mishra, H., Biomimetic Coating-free Surfaces for Long-term Entrapment of Air Under Wetting Liquids. (Accepted, Nature Communications #NCOMMS-18-00018C) 2018. 18. Wang, P.; Chung, T.-S., Recent advances in membrane distillation processes: Membrane development, configuration design and application exploring. J Membrane Sci 2015, 474, 39-56. 19. Khayet, M., Membranes and theoretical modeling of membrane distillation: A review. Advances in Colloid and Interface Science 2011, 164 (1-2), 56-88. 20. Drioli, E.; Ali, A.; Macedonio, F., Membrane distillation: Recent developments and perspectives. Desalination 2015, 356, 56-84. 21. Souhaimi, M. K.; Matsuura, T., Membrane Distillation. 1st ed.; Elsevier: 2011. 22. Khayet, M.; Matsuura, T., Membrane Distillation: Principles and Applications. 1 ed.; Elsevier: 2011; p 512. 23. Ng, K. C.; Shahzad, M. W.; Son, H. S.; Hamed, O. A., An exergy approach to efficiency evaluation of desalination. Applied Physics Letters 2017, 110 (18), 184101. 24. Ghaffour, N.; Lattemann, S.; Missimer, T.; Ng, K. C.; Sinha, S.; Amy, G., Renewable energy-driven innovative energy-efficient desalination technologies. Appl Energ 2014, 136, 1155-1165. 25. Eykens, L.; De Sitter, K.; Dotremont, C.; Pinoy, L.; Van der Bruggen, B., Membrane synthesis for membrane distillation: A review. Sep Purif Technol 2017, 182, 36-51. 26. Feng, S.; Zhong, Z.; Wang, Y.; Xing, W.; Drioli, E., Progress and perspectives in PTFE membrane: Preparation, modification, and applications. J Membrane Sci 2018, 549, 332-349. 27. Francis, L.; Ghaffour, N.; Alsaadi, A. S.; Nunes, S. P.; Amy, G. L., Performance evaluation of the DCMD desalination process under bench scale and large scale module operating conditions. J Membrane Sci 2014, 455, 103-112. 28. Bhadra, M.; Roy, S.; Mitra, S., Desalination across a graphene oxide membrane via direct contact membrane distillation. Desalination 2016, 378, 37-43. 29. Dumée, L. F.; Sears, K.; Schütz, J.; Finn, N.; Huynh, C.; Hawkins, S.; Duke, M.; Gray, S., Characterization and evaluation of carbon nanotube Bucky-Paper membranes for direct contact membrane distillation. J Membrane Sci 2010, 351 (1– 2), 36-43. 30. Hammami, M. A.; Croissant, J. G.; Francis, L.; Alsaiari, S. K.; Anjum, D. H.; Ghaffour, N.; Khashab, N. M., Engineering Hydrophobic Organosilica NanoparticleDoped Nanofibers for Enhanced and Fouling Resistant Membrane Distillation. ACS Applied Materials & Interfaces 2017, 9 (2), 1737-1745. 31. Rudolf, C.; Burger, W.; Tillmanns, R., Microporous polytetrafluoroethylene (PTFE) bodies with filler. Google Patents: 2001.
32. Hendren, Z. D.; Brant, J.; Wiesner, M. R., Surface modification of nanostructured ceramic membranes for direct contact membrane distillation. J Membrane Sci 2009, 331 (1–2), 1-10. 33. Wang, J. W.; Li, L.; Zhang, J. W.; Xu, X.; Chen, C. S., Beta-Sialon ceramic hollow fiber membranes with high strength and low thermal conductivity for membrane distillation. J Eur Ceram Soc 2016, 36 (1), 59-65. 34. Kujawa, J.; Cerneaux, S.; Koter, S.; Kujawski, W., Highly Efficient Hydrophobic Titania Ceramic Membranes for Water Desalination. ACS Applied Materials & Interfaces 2014, 6 (16), 14223-14230. 35. Jani, A. M. M.; Losic, D.; Voelcker, N. H., Nanoporous anodic aluminium oxide: Advances in surface engineering and emerging applications. Progress in Materials Science 2013, 58 (5), 636-704. 36. Petukhov, D. I.; Eliseev, A. A., Gas permeation through nanoporous membranes in the transitional flow region. Nanotechnology 2016, 27 (8), 085707. 37. Whitby, M.; Cagnon, L.; Thanou, M.; Quirke, N., Enhanced Fluid Flow through Nanoscale Carbon Pipes. Nano Lett 2008, 8 (9), 2632-2637. 38. Whitby, M.; Quirke, N., Fluid flow in carbon nanotubes and nanopipes. Nat Nano 2007, 2 (2), 87-94. 39. Lee, J. G.; Kim, Y. D.; Kim, W. S.; Francis, L.; Amy, G.; Ghaffour, N., Performance modeling of direct contact membrane distillation (DCMD) seawater desalination process using a commercial composite membrane. J Membrane Sci 2015, 478, 85-95. 40. Hitsov, I.; Maere, T.; De Sitter, K.; Dotremont, C.; Nopens, I., Modelling approaches in membrane distillation: A critical review. Sep Purif Technol 2015, 142, 48-64. 41. Karam, A. M.; Alsaadi, A. S.; Ghaffour, N.; Laleg-Kirati, T. M., Analysis of direct contact membrane distillation based on a lumped-parameter dynamic predictive model. Desalination 2017, 402, 50-61. 42. Lee, J.-G.; Jeong, S.; Alsaadi, A. S.; Ghaffour, N., Influence of high range of mass transfer coefficient and convection heat transfer on direct contact membrane distillation performance. Desalination 2018, 426, 127-134. 43. Hwang, H. J.; He, K.; Gray, S.; Zhang, J. H.; Moon, I. S., Direct contact membrane distillation (DCMD): Experimental study on the commercial PTFE membrane and modeling. J Membrane Sci 2011, 371 (1-2), 90-98. 44. Phattaranawik, J.; Jiraratananon, R.; Fane, A. G., Heat transport and membrane distillation coefficients in direct contact membrane distillation. J Membrane Sci 2003, 212 (1-2), 177-193. 45. Andrjesdottir, O.; Ong, C. L.; Nabavi, M.; Paredes, S.; Khalil, A. S. G.; Michel, B.; Poulikakos, D., An experimentally optimized model for heat and mass transfer in direct contact membrane distillation. Int J Heat Mass Tran 2013, 66, 855-867. 46. Kaufman, Y. C., S.-Y.; Mishra, H.; Schrader, A. M.; Lee, D. W.; Das, S.; Donaldson, S. H.; Israelachvili, J. N., , A Simple to Apply Wetting Model to Predict Thermodynamically Stable and Metastable Contact Angles On Textured/Rough/Patterned Surfaces. . The Journal of Physical Chemistry C 2017. 47. Bico, J.; Thiele, U.; Quere, D., Wetting of textured surfaces. Colloids and Surfaces a-Physicochemical and Engineering Aspects 2002, 206 (1-3), 41-46.
48. Wu, C.; Leese, H. S.; Mattia, D.; Dagastine, R. R.; Chan, D. Y. C.; Tabor, R. F., Study of Fluid and Transport Properties of Porous Anodic Aluminum Membranes by Dynamic Atomic Force Microscopy. Langmuir 2013, 29 (28), 8969-8977. 49. Le Coz, F.; Arurault, L.; Fontorbes, S.; Vilar, V.; Datas, L.; Winterton, P., Chemical composition and structural changes of porous templates obtained by anodising aluminium in phosphoric acid electrolyte. Surface and Interface Analysis 2010, 42 (4), 227-233. 50. Butt, H.-J.; Kappl, M., Surface and Interfacial Forces. Wiley-VCH Verlag GmbH & Co.: 2010. 51. Kalempa, D.; Sharipov, F., Numerical modelling of thermoacoustic waves in a rarefied gas confined between coaxial cylinders. Vacuum 2014, 109, 326-332. 52. Gatapova, E. Y.; Graur, I. A.; Sharipov, F.; Kabov, O. A., The temperature and pressure jumps at the vapor–liquid interface: Application to a two-phase cooling system. Int J Heat Mass Tran 2015, 83, 235-243. 53. Sharipov, F.; Strapasson, J. L., Ab initio simulation of rarefied gas flow through a thin orifice. Vacuum 2014, 109, 246-252. 54. Liu, C.; Li, Z. G., On the validity of the Navier-Stokes equations for nanoscale liquid flows: The role of channel size. Aip Advances 2011, 1 (3). 55. Sharipov, F., Rarefied Gas Dynamics. Wiley-VCH: Berlin, 2016. 56. Tabor, D., Gases, Liquids and Solids and Other States of Matter. Cambridge University Press: 2000. 57. Ernst, M. J.; Hemond, H. F., Multicomponent vapor transport model for viscous, transitional, and molecular flow. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 1995, 13 (6), 2962-2971. 58. Remick, R. R.; Geankoplis, C. J., Binary Diffusion of Gases in Capillaries in the Transition Region between Knudsen and Molecular Diffusion. Industrial & Engineering Chemistry Fundamentals 1973, 12 (2), 214-220. 59. Rao, G.; Hiibel, S. R.; Childress, A. E., Simplified flux prediction in directcontact membrane distillation using a membrane structural parameter. Desalination 2014, 351, 151-162. 60. Chen, X.; Han, P., A note on the solution of conjugate heat transfer problems using SIMPLE-like algorithms. Int J Heat Fluid Fl 2000, 21 (4), 463-467. 61. Abad, B.; Maiz, J.; Martin-Gonzalez, M., Rules to Determine Thermal Conductivity and Density of Anodic Aluminum Oxide (AAO) Membranes. J Phys Chem C 2016, 120 (10), 5361-5370. 62. CRC Handbook of Chemistry and Physics. 1998. 63. Lemmon, E. W.; McLinden, M. O.; Friend, D. G., Thermophysical Properties of Fluid Systems" in NIST Chemistry WebBook, NIST Standard Reference Database Number 69. National Institute of Standards and Technology, Gaithersburg MD, 20899, 2018. 64. Nayar, K. G.; Sharqawy, M. H.; Banchik, L. D.; Lienhard V, J. H., Thermophysical properties of seawater: A review and new correlations that include pressure dependence. Desalination 2016, 390, 1-24. 65. Sharqawy, M. H.; Lienhard, J. H.; Zubair, S. M., Thermophysical properties of seawater: a review of existing correlations and data. Desalination and water Treatment 2010, 16 (1-3), 354-380. 24
66. Peichun, T.; Peters, A. M.; Pirat, C.; Wessling, M.; Lammertink, R. G. H.; Lohse, D., Quantifying effective slip length over micropatterned hydrophobic surfaces. Physics of Fluids 2009, 21 (11), 112002 (8 pp.)-112002 (8 pp.). 67. Beysens, D., Dew nucleation and growth. Cr Phys 2006, 7 (9-10), 1082-1100. 68. Lv, P. Y.; Xue, Y. H.; Liu, H.; Shi, Y. P.; Xi, P.; Lin, H.; Duan, H. L., Symmetric and Asymmetric Meniscus Collapse in Wetting Transition on Submerged Structured Surfaces. Langmuir 2015, 31 (4), 1248-1254. 69. Sharipov, F.; Kalempa, D., Gaseous mixture flow through a long tube at arbitrary Knudsen numbers. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 2002, 20 (3), 814-822. 70. Blunt, M. J., Flow in porous media—pore-network models and multiphase flow. Curr Opin Colloid In 2001, 6 (3), 197-207. 71. Zhang, L.; Tang, B.; Wu, J.; Li, R.; Wang, P., Hydrophobic Light‐to‐Heat Conversion Membranes with Self‐Healing Ability for Interfacial Solar Heating. Adv Mater 2015, 27 (33), 4889-4894. 72. Tan, G.; Zhao, L.-D.; Kanatzidis, M. G., Rationally Designing High-Performance Bulk Thermoelectric Materials. Chemical Reviews 2016, 116 (19), 12123-12149. 73. Mishra, H.; Cola, B. A.; Rawat, V.; Amama, P. B.; Biswas, K. G.; Xu, X. F.; Fisher, T. S.; Sands, T. D., Thermomechanical and Thermal Contact Characteristics of Bismuth Telluride Films Electrodeposited on Carbon Nanotube Arrays. Adv Mater 2009, 21 (42), 4280-+. 74. Yu, J. K.; Mitrovic, S.; Tham, D.; Varghese, J.; Heath, J. R., Reduction of thermal conductivity in phononic nanomesh structures. Nat Nanotechnol 2010, 5 (10), 718721. 75. Naidu, G.; Shim, W. G.; Jeong, S.; Choi, Y.; Ghaffour, N.; Vigneswaran, S., Transport phenomena and fouling in vacuum enhanced direct contact membrane distillation: Experimental and modelling. Sep Purif Technol 2017, 172, 285-295.
Graphical abstract
Report "Evaluating the potential of superhydrophobic nanoporous alumina membranes for direct contact membrane distillation"
Your name
-Select Reason-
Other Terms Of Service Violation
File a copyright complaint
Our partners will collect data and use cookies for ad personalization and measurement.
Learn how we and our ad partner Google, collect and use data
Agree & close


text:
24 hours for you
The source water was groundwater in abandoned silver mine, naturally contaminated by 60-80 ppb of arsenic and antimony below 10 ppb. This water represents one of the sources of drinking water for Park City and constitutes about 44% of the water supply.Get Price
Arsenic & Antimony Removal with Elevated Competing Ions Arsenic & Antimony Removal with Elevated Removal with Elevated Competing IonsCompeting Ions Milt Larsen, P.E., Kennedy/Jenks Consultants John Buzzone, P.E., Washoe County Dept. of Water Resources Alex Peterson, P.E., Kennedy/Jenks ConsultantsGet Price
Certain soluble salts containing cations, such as sodium, potassium, magnesium and calcium, that have the property of combining with acids to form neutral salts. Most commonly used in water treatment areGet Price
What is Electrocoagulation? Electrocoagulation is an electro-chemical process that simultaneously removes heavy metals, suspended solids, emulsified organics and many other contaminants from water using electricity instead of expensive chemical reagents.Get Price
Filtration is a process used to separate solids from liquids or gases using a filter medium that allows the fluid to pass through but not the solid. The term "filtration" applies whether the filter is mechanical, biological, or physical. The fluid that passes through the filter is called the filtrate.Get Price
During the chemical coagulation process, the valence state of arsenic and antimony could affect the removal efficiency. Thus, the oxidants and reductants areGet Price
This article is the third in a series on industrial water treatment focusing on inorganic contaminants. While regulatory limits are being established (), the process of identifying a cost-effective treatment process should be undertaken ().Potential water treatment processes for inorganic contaminants can be grouped into three categories physical, chemical, and biological.Get Price
Removing Heavy Metals From Wastewater Introduction This manual provides general guidelines on how to remove dissolved metals from wastewaters for discharge to sanitary sewer systems. Each of the various stages or operations of wastewater treatment will be discussed with their role in the metals removal process.Get Price
antimony. antimony is a semimetallic chemical element which can exist in two forms the metallic form is bright, silvery, hard and brittle; the non metallic form is a . Get PriceGet Price
Water Treatment Donald Burger, P.E. Test Masters Educational Services, Inc. Drinking Water Standards Drinking water standards are promulgated by the United States Environmental Protection Agency (EPA) to protect public health from waterborne diseases. Maximum Contaminant Level Goal (MCLG)Get Price
Direct filtration using ferric chloride as coagulant, could be an appropriate technology to reduce arsenic levels below 10 µg/L for the given groundwater. Key words arsenic removal groundwater ferric chloride coagulation flocculation direct filtration.Get Price
Some cadmium compounds are able to leach through soils to ground water. When cadmium compounds do bind to the sediments of rivers, they can be more easily bioaccumulated or re-dissolved when sediments are disturbed, such as during flooding. Its tendency to accumulate in aquatic life is great in some species, low in others.Get Price
natural resource company that has three product lines (1) antimony, (2) zeolite, (3) precious metals. UNITED STATES ANTIMONY CORPORATION ORPORATE HIGHLIGHTS Permitting of the Los Juarez gold/silver/antimony property mill in Mexico is expected sometime before the end of October, 2016.Get Price
coagulation by introducing highly-charged polymeric metal hydroxide species. These species neutralize the electrostatic charges on suspended solids and oil droplets to facilitate agglomeration or coagulation and resultant separation from the aqueous phase. The treatment prompts the precipitation of many metals and salts.Get Price
Electrocoagulation Vs. Chemical Coagulation. The chemicals used in wastewater treatment include Alum, Ferric chloride, Ferric sulfate, Ferrous sulfate, and Lime. The inherent disadvantages associated with most chemical unit processes (activated carbon adsorption isGet Price
Electrocoagulation Water Treatment Process Electrocoagulation (EC) technology is based upon a process generally referred at as "adsorption and co-precipitation". The electrocoagulation water treatment solution offers an alternative to the use of metal salts or polymers and poly-electrolyte additives for breaking stable emulsions andGet Price
wastewaters. Since the chemical properties of antimony traditionally have been compared with those of arsenic, several methods for reducing arsenic have been tried out on antimony as well. Some of these methods include precipitation and coagulation of antimony ions with ferric or aluminum salts which have shown to be somewhat effective.Get Price
"Removal of Antimony (III) and Antimony (V) from Drinking Water by Ferric Chloride Coagulation Competing Ion Effect and the Mechanism Analysis." Separation and Purification Technology 76 184 190.Get Price
Article 12. Best available technologies (BAT) §64447. Best available technologies (BAT) Microbiological Contaminants. The technologies identified by the Department as the best available technology, treatment techniques, or other means available for achieving compliance with the total coliform MCL are as followsGet Price
ELECTROCOAGULATION vs CHEMICAL COAGULATION. In the case of alum and iron, 1 mole will precipitate 1 mole of phosphate. These chemical precipitation reactions must be considered in light of the many competing reactions, their associated equilibrium constants, the effects of alkalinity, pH, trace elements, and ligands found in wastewater.Get Price
Guidelines for Canadian Drinking Water Quality Guideline Technical Document Antimony. Little information is available on the removal of antimony from source water during water treatment. However, as antimony is chemically Footnote 24 Footnote 25 could possibly be used for antimony removal. Footnote 26 Coagulation with alum orGet Price
Antimony is a metal that may be found in some public and/or private supplies of drinking water. It is a metal that according to the EPA (Environmental Protection Agency)can be problematic to your health if found in amounts that exceed the standard set by themGet Price
The coagulation experiments were conducted to study the effect of pH (410) on Fe solubility and As, Sb removal, where 0.1 mM (27.029 mg/L) FC dose was used for solutions with 1 mg/L As(III, V) and Sb(III, V), respectively [13].Get Price
Following coagulation, a process such as multimedia filtration with automated backwashing is generally used to remove precipitated arsenic and/or antimony. Read More Trends in mine water treatmentGet Price
AdEdge's biological filtration products include biottta® and NoMonia, which can both help water utilities achieve non-detectable levels of ammonia, arsenic, iron and manganese. Because biological filtration does not use chemicals, very low, non-hazardous waste is produced, and there is high water recovery.Get Price
The production of "secondary antimony" (i.e. the recovery of antimony from alloys and residues) forms an important means of obtaining the metal. In the United States of America in 1928, between 170,000 and 180,000 tons of old lead accumulators containing 3 per cent, antimony were available.Get Price
Coagulation filtration is effective at removing arsenic, manganese, sulfides, and iron. This process allows for a high rate of flow as well. Oxidation/filtration systems are designed to be standalone options.Get Price
According to the international charity Water Aid, one in eight human beings, mostly in the developing world, goes without clean, safe water. Every 20 seconds, one child dies from diarrhea caused by contaminated water and poor sanitation. In wealthier countries, illness and death from waterGet Price
Wastewater treatment polymers remove solids from water by means of both coagulation and flocculation. It would be well if we first provided definitions for both coagulation and flocculation. The terms are quite different, however, are often used interchangeably.Get Price
Apr 03, 2018 · Coagulation water treatment is the first step in chemical wastewater treatment. Instead of passing over particles that would otherwise slip through the filter and fall too slowly to be trapped as sediment, coagulation clumps them together so they are more easily removed. Most of us know coagulation from anatomy class.Get Price
If you are interested in our company or products, welcome to visit our company or local offices; you can also get contact with us through online consulting, demand table submission, e-mails and telephones. Our staff shall wholeheartedly provide product information, application knowledge and good service for you.

subset: commoncrawl


text:
Category Action
Showing results 2181 - 2200 of 4158 found results.
Waiter (1202)
Christmas Memory (1202)
Worker angst
Starship Operation Dark Matter (1202)
Collect all your presents in this christmas themed memory game! You'll need a good visual memory and be fast in this action puzzler with extensive gameplay. Complete 4 difficulty modes with 25 levels each. When you make mistakes, the presents start moving around, making each level a harder challenge!
Christmas Memory features an achievement system (click the presents under the tree) for additional replay value.
Roly-Poly Cannon (1202)
Protect our solar system. We need the computer data of starship one. Fight again alien spaceships. Cross reliably the mine field. Give Starship One Dark Matter Escort protection and flies reliably to Star cruiser Razorblade back.
6 Player Online Soccer (Multiplayer Pong) (1202)
Roly-Poly bugs have settled down in the area. It is time to show these unwanted visitors that they have chosen the wrong place to hang out!
Don?t mind their cute appearance, just get rid of them one way or another. Your trusty cannon and an accurate aim is all you need to complete this task.
Small Ball War (1202)
Mulitplayer Soccer (Pong) Game. Play in Teams with up to 6 Players. Upgrade your paddle, and win your league...
Monster Poise (1202)
This game is they seem very simple, but believe that it is not.
The role of a small fighter and his three friends are trying to kill all the enemies of the opposite party.
Just when you hold the left mouse button to charge and the release of only shoot. Each of the enemies is a need to hit three times to kill him. Until the fourth round and the number of enemies you is still the same number. So pay good attention, Have a good point and shot and get to the furthest.
Battlenoid (1202)
Help Creature to gain his friends respect. Don?t let him fall down. You have to balance his body so as not to fall. Use arrows to control.
Spider's Escape (1202)
Battlenoid is an original take on the retro legend Arkanoid and the breakout genre. The game features a customizable Skirmish mode, 40 levels to master, and a local two-player mode.
Suals Quest Episode 1: The Cloud King RPG (1202)
Your eggs have been kidnapped !!! Ride the spider to collect as eggs as you can.
Space Attacker (1201)
This is Episode 1 of Suals Quest series. In this episode you help the cloud nation defend against the savage orcs. This game was made for the RPGDX 48 Hour Side-Scrolling RPG Contest.
Soda Shooter Olympics (1201)
Experience some awesome side scrolling action in this space shooter!
Planet Ride (1201)
In this game, using the mouse, shoot as many soda bottles as you can using a variety of weapons and tools. Scores are submitted worldwide. Will you become a Soda Shooter Olympics winner?
Deep Space Miner 2 (1201)
Avoid rocks and enemies!
How far can you go?
Pollenization (1201)
Completely New Version! Asteriods on Steriods as you blast your way through space collecting precious metals to trade for weapons and power ups.
One-man Siege (1201)
Help your bee pollenate the flowers!
Button Masher! (1201)
Destroy enemy towers using the laws of physics in this original game featuring Box2D physics engine!
The Darkness Project Deathmatch (1201)
A fast pace clicking game!
StarFly 2 CosmicGladiator (1200)
A single & multiplayer shooting game.
Game features:
* 3 maps
* multiplayer game support
* singleplayer bot fighting
* 5 weapons
* in-game grenades & medkits
* in-game chat
* comfortable user interface with different game & performance settings
* user avatar creator
Jumping Troll (1200)
Fly in your space ship in the galaxy shoot at other ships with lasers.
Pages: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 [110] 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208
Top Frog Games
50 Most Played Games
10 Paheliyan (26882)
Powerpool 2 (26657)
Game based on Indian Elections 2009
Mini-Pool with powerups and three different tables
Video Poker (21422)
Clear the field! Combine cards untill you reach 13!
100 Quickshot Fun (20276)
Video poker game in Flash
Flash Roulette (19030)
100 targets will appear on screen. Can you shoot them all down? Play with mouse or wiimote. Features leaderboard.
10 Gnomes 12 (18216)
Amazing Online Roulette Game in Flash
Cave Flyer 2 (17914)
You have 10 minutes to find 10 gnomes hidden in the pictures. Find clickable areas to navigate through the location.
Straight Poker (16359)
Compete with other players worldwide for the title of grand master cave flying champion. In this sequel to the 'smash hit' cave flyer, your ship now leaves a sparkly trail, and makes a fiery explosion when it smashes into a cave wall. And it's slightly harder! Do you have what it takes to cave-fly your way to glory?
Poker Machine (16062)
Funny video poker game.
Dartmaster9in1 (15708)
Poker slot machine
Fruit Machine (15320)
Cool DARTS game for 1 or 2 players, 9 different games, 3 difficulties and 27 leaderboards!
Spongebob Slots (15220)
Pull the lever on this slot machine and win some big money
Burger Time (14704)
Spongebob Slots is a bright and colorful 3 reel casino style slot machine game featuring a Spongebob Squarepants theme colors and characters.
Bratz's Fashion Christmas (14211)
Pick up the ingredients to make your burger.
Fruite Slots (14129)
Christmas is coming and bratz wants to get a happy and fashion holiday like you too.Please help her choosing a cool fashionable dress up.
10 Gnomes 11 (13735)
Fruite Slots is a fun and addicting fruit themed slot machine game with 3 modes of play. This game features high scores in all game modes! Game modes include Time Trial Mode where you must win as much money as you can in 60 seconds starting with 3 credits. 3 Spins Mode where you only have 3 spins to win as much money as you can and Freeplay Mode where you can play as long as you like starting with 3 credits.
Froggy (13481)
find 10 gnomes within 10 minutes
Bumper Cars Championship (12909)
Why did the frog cross the road?
Prevent froggy from becoming another sad case in the world of spiralling road kill statistics.
Guide him from one side of the highway to the other, then over the river. Avoid the hungry alligators, and use the turtles and logs as stepping stones!
Get him and his friends all to the other side to become a frog saving hero! But more importantly to earn points!
Sonic Boom Town (12850)
Bump the opponents and knock them out in this interesting competition, and try to survive till the end.
15 Puzzle (12829)
Drive around the city in your car and blast your music to destroy buildings.
Mahjong Beauty (12784)
Classic 15-puzzle sliding tiles game
Über Battle (12526)
Traditional mahjong game, play with mouse click. You play with 3 girls, and win the round by creating a standard mahjong hand which consists of a certain number of melds, namely four for 13-tile variations and five for 16-tile variations, and a pair. Win the game and save your score. You can learn how to play Mahjong games at Win Mahjong.
110m Hurdles (12436)
Power up attack, swing your massive sword,use magic, potions and buy stronger weaponry.
1 Starship (12158)
Race in this 110M Hurdles track and field event
Drag Racer v2 (12033)
Very Cool top down shooter. use the mouse to more your ship around and the button to fire.
100 Snowballs (11774)
Shift into gear and floor the pedal as you dragrace against the computer tune up your car modify eng
Hulk Smashup (11464)
Winter Fun for Kids - 100 Snowballs!!! What can you make?
Children love to play in the snow! 100 Snowballs gives children the opportunity to simply have fun by clicking and dragging snowballs around a wintry scene. They can create anything they imagine - as long as it only uses 100 snowballs! Similar to legos. Great fun in the computer lab!
The Simpliest Snowboarding (11441)
Destroy everything in sight. Climb up buildings and topple them with your might.
0 Gelert TV v1.0 (11368)
The simpliest but cool snowboarding flash-game
101 Dalmatians (11347)
archery from the film GELERT
101 Dalmatians Jigsaw 2 (11326)
Classic jigsaw fun with 101 Dalmatians in 49 pieces. Drag and drop the pieces to fit them together.
101 Dalmatians Jigsaw 3 (11145)
Classic jigsaw puzzle fun with 101 Dalmatians - 49 pieces. Drag and drop the pieces to fit them together.
1493 Battle over Pacific (11138)
High quality jigsaw puzzle with 101 Dalmatians in 49 pieces. Drag and drop the pieces to fit them together.
Snow Storm (11083)
WW2 Vertical shooter - Fly with your P38 Lighting and beat the enemies
10++ (11019)
There has just been a snow storm! Your job is to clear the snow from the parking lots using your sno
Spy Hunter (10944)
Addictive brain teaser with neat and stylish graphics.
1-i (10842)
Rave down the highway in your equipped car blasting through enemies and avoiding danger.
10 Gnomes 5 (10809)
Catch the green blobs
10 Trolls (10688)
find 10 Gnomes in 10 minutes.
TGFG Racing (10688)
Find all 10 of the cute little creatures that have gotten lost!
10 Gnomes 9 (10553)
Race around the track smashing into your opponents to knock them off and picking up turbo so you can
ClickDragType (10551)
find 10 gnomes within 10 minutes. Part 9.
10 Gnomes 8 (10519)
The only instructions for this game is to click, drag, and type your way to the next puzzle.
Ace Racer (10515)
find 10 gnomes within 10 minutes. Part 8.
1945 Tower Defense (10441)
Ride on your skidoo water boat over the waves, jump over dolphins and pull tricks by flying off ramp
Balloon Headed Boy (10310)
1945 Tower defense is based from th peral habour attack with many attacks from planes.
defend you land with turret from the japanese planes
Cone Crazy (10266)
Help Balloon Headed Boy race through 35 levels of rubberised madness - collect farty flowers to inflate his head and soar between the platforms, thwop those frogs, keep your head above the rising waters, and rescue the balloons so the birthday party can go ahead as intended!
10 gnomes 6 (10127)
Knock over as many cones as you can in the given time limit. Red cones are worth 10 points and the y
10 Gnomes 10 (10054)
find 10 gnomes within 10 minutes find 10 gnomes within 10 minutes. Part 10.


text:
How to Calculate Total Addressable Market Size and Perform TAM Analysis
Did you know? Most new startups grow from an extraordinary thought. Or what it may intrigue?
Thus, this is a simple query to pose. Because it assists with knowing how much development potential is not too far off for your startup. So, Total Addressable Market (TAM) is a magnificent measurement to see. When planning to check the growth potential of your startup.
What is the total addressable market (TAM)?
Hence, the total measure of money you may make we know selling what you are selling as the TAM. Additionally, it is called a total addressable market, or TAM for short. Thus, another perspective about it is the total measure of interest. So, it presents in the market for your product and service.
How to compute TAM?
Also, it might be tough to compute the TAM. Particularly, if a considerable lot of the rivals in the space. Additionally, they are secretly held and misty about marketing figures. Now, there are three choices for measuring TAM:
- Top-down, it extrapolates the TAM size from industry research
- Bottom-up, it accesses data from your organization's early sales to measure the market.
- Value theory, this calculates how your product's worth will affect buyers' conduct.
Now, we should dig into these three choices on the most proficient method to compute TAM.
Top-down TAM Investigation
Generally, Top-down TAM computations are being founded on an existing work by market-research firms. For example, Gartner and Forrester. Yet, to make specific determinations about specific markets.
Thus, the more extensive research these organizations have done regularly should be enhanced. Or refined by additional evaluations. For example, telephone or email overviews, finished by third-party advisors.
So, by using this system has different traps. Mainly because potential investors may not discover the numbers reliable. So, could the research and the overviews be dependable? When they might be founded on not so much straightforward organization data and self-revealed information?
Moreover, utilizing a "canned" TAM number likewise overlooks the way. And it is the presentation of certain products that can change the TAM by entering the market.
Ride-sharing organizations, for instance, extended the TAM past the customary taxi market. Because non-taxi-consumers began looking for rides once they understood they could use an application.
To go anyplace and abstain from disturbing spare change. Furthermore, Uber and Lyft expanded the TAM that made any figuring. Hence, they may have done about the total addressable taxi-riding market old.
Bottom-up TAM analysis
Likewise, the bottom-up TAM methodology will give you progressively exact numbers. To some degree by enabling you to incorporate any remarkable elements. For example, the development of the TAM because of your passageway into the market — from the very beginning.
Now, you can compute this number by extrapolating from your information on your present estimating and use. Also, take that number and apply it to the bigger client base of your objective market.
Besides, you can make sense of your objective market by researching the kind of clients you think will purchase your products. For instance, if you sell a B2B software arrangement that works best for medium-sized firms.
Then you can figure out the quantity of those organizations in a suitable area. The number of representatives they have all things considered. And the quantity of the individuals who will probably access your software.
TAM = (Annual Contract Value) x (# of potential Accounts)
Now, let's suppose your organization sold a custom representative service software. And it is reasonable for music production organizations with 100 to 500 workers at a level pace of $1,000 every year.
So, if your yearly contract value (ACV) is $1,000. And you decide there are 5,000 potential records (total number of music production organizations with 100 to 500 representatives). Then, your TAM would be $5,000,000 ($1,000 x 5,000).
Doing this sort of TAM investigation constrains you to contemplate product-market fit. So, the TAM figure they base you on a strong feeling of who precisely makes up that market.
Also, you can even separate your TAM into different industry portions or geographic territories. To show how you can move toward different parts of the market. To win yet much of the TAM as could reasonably be expected.
Value theory TAM analysis
Well, the value hypothesis technique for computing the TAM depends more on supposition and mystery. So, its decisions will be murkier, yet helpful.
To figure TAM utilizing the value hypothesis. Now, estimate the value that your product gives to specific clients. And, whether you can adequately catch that value through estimating.
Finally, this computing technique is best to get the feeling of the TAM for new highlights or moves up to existing products. Or, when you are offering a novel product for sale to the public, that will successfully make its class.
To utilize this method, it's essential to ponder what clients discover significantly. And the amount they might be eager to pay for that value.
Next, test what number of clients may find that measure of value in the product and pick it over other options.


text:
Thanks for visiting our Makeney handyman website, we are professionals in house enhancement and home repairs and maintenance in the Makeney Derbyshire DE56 0 East Midlands area.
We are a reputable business well known and respected all over the locations we serve for our consistent quality services.
Our vast experience in this field comes from the many number of years of providing efficient services to our clients. Due to that, we have lots of repeat customers spread throughout the local neighbourhood.
Makeney Handyman - Local Handy man 247 - Handyman In Derbyshire - Property Repair work
When preparing to maintain our houses or take good care of our properties, we can all admit that our biggest hope is to work with a professional who is not just reputable, however likewise certified, friendly, and able to successfully undertake the job to completion.
At Makeney Handyman Services, we've made all of that our mission. In addition to that, our business is completely guaranteed, making sure that you will be secured from any liabilities that may take place during the duration we'll be addressing the job you have appointed us.
Call us today for your free estimate on 01332 806 886
Below, we've listed a variety of handyman services our friendly and skilled group can undertake.
Our Services
• Property/Home maintenance
• Gardening works
• Keys or Locks
• Painting and decor
• Simple electric repairs
• Cleaning Services
• Property Makeovers
• DIY completion
• Fencing
• Patio Areas
Do not stress if the work you require to be done isn't listed here. Providing that it falls under house enhancement and home repair and maintenance, do not think twice about getting in contact with us.
Why Hire A Makeney East Midlands Handyman Service?
Are you uncertain on who to employ between a number of handyman services or not even sure why you should employ one in the first place?
Well, we have compelling reasons you should hire us and more notably, why you should employ a handyman to undertake your house enhancement, maintenance or repair work jobs.
No Task Is Too Small For Our Company In The Makeney Area.
It doesn't matter to us whether your job is little or big; we are always eager to assist.
Whereas other business may charge you high prices or not be interested at all in carrying out the little jobs, we promise affordable rates and top class work.
Whether it's a dripping tap, roofing system extensions, replacing a light bulb or installation of a new sink, trust us to do it passionately and to your satisfaction.
We Do Not Charge For Quotes
We do not impose any charges on our customers till our handyman reaches your house or facilities to do the job. Expect a one-hour minimum charge and just half-hour increments afterwards. As soon as the job reaches it's completion, just make the payment to the handyman and then write your signature on the work order. It's that basic.
Friendly and Professional Makeney Handyman
.Our handymen are trained and certified in several trades, consisting of joinery, plumbing, electrical, roofs, masonry, landscaping, just to mention a couple. On top of that, they are disciplined, well-disposed, and knowledgeable when it concerns health and security, asbestos awareness, and manual handling. You can, therefore, trust us to work on almost any job within our field in a professional and acceptable way.
Quality Derbyshire Services.
Whether you are a homeowner, proprietor, commercial business or letting agent, we have the resources and capacity to manage your special needs and requirements. Whatever work you require to be performed in your house or home, we always match the ideal handyman to the job in question, to your location, or when you require the job to be done. This is to permit the work to be done properly, to be completed on time, and to your satisfaction.
Call us today for your free estimate on 01332 806 886
Satisfaction Guarantee.
Part of our goal is to leave an enduring impression so as you have every reason to hire us once again. Therefore, we take notice of information and always make sure that your requirements are satisfied. In case you are not completely pleased with the work we've performed, the appointed handyman will go back to correct the work and you will not be charged anything extra.
Why Entrust the work to a Professional Handyman?
Approved, you may be able to repair your leaking faucet, paint your living room, or undertake garden works, however very few people have the time and resources, leave alone the expertise to do such work or things like pipes as a genuine professional would.
We could also make the point that accidents might happen or even the very same problem might repeat once again quicker than you expected because of the way that the work was done.
That, and the factors listed below explain why you should leave your house remedial jobs or home repair work and maintenance work to a professional.
Security– Incorrect repairs or substandard work when carrying out jobs such as plumbing etc might lead to much bigger issues later on, putting your house and family in possible danger and forcing you to spend more on fixing the problems.
Health– Take the case of sluggish leaks resulting from a bad repair work. This might lead to a standing water scenario where mould spores can flourish, eventually exposing you and your family to mould infection.
Financial threats– Whenever you try to repair a structural problem in your house without success or possibly successfully but only for the problem to resurface once again, most likely even worse than in the past, you may end up parting with bigger sums of cash to have it repaired.
Likewise, leaving basic issues in your house like a broken window, faulty electric switches, broken fences unattended for an extended period of time (since you are hectic or pay less attention to them) might lead to much bigger issues that might cost you big sums of cash in future.
Looking at all these scenarios, there's plainly a lot to gain when you employ a professional handyman to look after the structural issues in your home or business or house.
Call us today for your free estimate on 01332 806 886
What To Expect From Us.
As soon as you've shared with us your list of requirements, we'll encourage on what should be bought/ordered. If you wish to us to bring the products, we'll happily do so and show you the receipts prior to passing the expense on to you.
We will likewise offer all the technical support you need, consisting of having our skilled handymen supply the smaller sized products needed for the task, consisting of things like screws, glues, fillers, adds, tap washers, and so on.
If you discover that you are in need of a skilled, reputable, and professional handyman to repair your house or home, trust us to provide beyond your expectations. If it's an emergency, we'll get among our knowledgeable handymen to your location on the same day. We are likewise readily available during the evening and on the weekends in the Makeney Derbyshire DE56 0 East Midlands area.
We serve these areas too..
Milford, Duffield, Holbrook, Holbrook Moor, Duffieldbank, Coxbench, Flaxholme, Cowhill, Bargate, Lower Kilburn
We are your local handyman service. View the map below to see how quickly we can be at your location.


text:
Lipstick Revlon 61189
Sale price
£ 8.21
Regular price
Unit price
Tax and FREE shipping included
Lipstick Revlon 61189 is what you need to maximise your appeal! Try the quality of 100% original Revlon products and let the best professionals enhance your beauty.
- Gender: Lady
- Capacity: 5,9 ml
- Colour: Nº 635 Passion


text:
heat pump efficiency temperature continuing professional education series geothermal heat pumps concept to completion thermodynamics.
best heat pump air conditioner system cycle time thermodynamic,energy saving by installation of double bundle type heat pump ,swimming pool heat pump , pond heat pumps pool heating advice, energy efficiency in all seasons with quay heat pump water heaters,heat pump efficiency temperature larger image , air source heat pump to water,does the heating efficiency of air source heat pumps vary ,commercial heat pump , heat pump efficiency temperature.
Related Post
Decorative Shower Curtain Hooks Wallpaper Organizer Low End Table Outdoor Patio Blinds Revere Copper Bottom Cookware 72x96 Shower Curtain Suede Stain Remover Circulon Vs Calphalon How To Use Microsoft Surface Pen Bear Baby Shower Decorations Toile Patterns Wok For Electric Stove Teen Bathroom Turtle Theme Baby Shower Homemade Drag Harrows


text:
- Greggory B. Oberg, Esq.
SCA Speaks at May NSCCA Meeting
Mortgage Industry Insight: One of the great things about SCA is the range of issues we get to see, and the wealth of knowledge we get to tap into while working with dozens of clients on a monthly basis. Today, we'll share some information about SCA's presentation to NSCCA.
By Gregg Oberg:
Last week, I met with members of the local mortgage industry up in Saugus at Jimmy's Steer House for a meeting of the North Shore Consumer Credit Association (NSCCA). I'd like to thank my friend Sue Dunbar for the invite, it was a blast. The event of the evening was NSCCA awarding scholarships to SEVEN worthy college students in the area. They're coming for our jobs people, incredibly impressive young people. The steak was also excellent.
Before all that, I was honored to serve as the warm up act while covering the thrilling topic of Vendor Management, focusing on third party risk assessment and due diligence. This is a topic that's been close to my heart since early in my legal education, but never has it been more front-of-mind than it is today.
Cyber Risk Takes Center Stage
I've given the talk a few times before, and usually the focus is on either the business function the third party performs (and by necessity how it impacts your business), or the prevention of knowing or intentional fraud in these relationships. But this time, Data Security concerns immediately rose to the front of the discussion. Rather than asking "how do I make sure the closing agent gets his job done on time," people are now asking "how do I make sure my vendors don't expose me to cyber risk?"
The answer to the latter is largely the same as the former---turn over every stone and have a suspicious mind towards third party relationships. After all, you're entrusting them with your name and reputation, the very thing we trade on in this industry. It really is that simple in a big-picture sense; understand and quantify your risks to the extent possible; and make informed decisions. As we saw in the ATR case of Elliot, nobody expects us to predict the uncertainties of the future. If we could do that, we'd just bet the farm on Country House and head down to Martha's Vineyard for the rest of the summer (or our lives, but it does get cold there…).
But I've Got 68 Vendors
Depending on your regulator, the "important" ones are defined differently. The common thread running through each definition is risk. Often times, regulation is an attempt to legislate prudence; just as you could say motorcycle helmet mandates are attempts to legislate intelligence. In a sense, a "critical" or "significant" vendor is anyone who can tank your reputation, your business operations, or the consumers' interests. Michael Scott probably isn't "critical," but Encompass definitely is. At this point, anybody who can sniff consumer information should be considered "significant."
My Best Advice (in a 500 word format)
First, I'd say join a trade group like NSCCA and you can get this advice first had. But second, I'll leave you with a David Letterman style Top 10 (please try to read in Dave's voice):
Written Service Level Agreements (SLA)
Consumer Complaints with/about Vendor
Gather Work Papers—examiners more and more are looking at underlying audit documentation
On-Site Visits—certain vendors will require enhanced initial and ongoing due diligence
Reduce # of Vendors When Possible/Reasonable
Centralize Vendor Management Role
Ensure Board Reporting, Training, and Involvement in Vendor Management
Treat 3rdParties Obtaining ANY Consumer Data as "Significant" or "High-risk" Vendors
Standardize Contractual Agreements and SLA Templates to Streamline Onboarding
Spillane Consulting Associates has served the residential mortgage lending business since 1991. We have specialized in mortgage banking consulting services and provided quality control reviews, risk management and process consulting and employee training to credit unions, community banks and non-depository institutions. We are a thought leader on the strategic growth of residential mortgage lending. You can learn more by visiting our website, or scheduling a meeting with me or one of my colleagues.
SCA Compliance Hotline: Need a question answered quick?
(781) 356-2772
Thanks so much for reading our weekly newsletters. We're not always going to be perfect, but because we always do our best and try not to overpromise, we hope that we're always going to be trustworthy. Your calls and e-mails are very helpful - please keep contributing.