Molecular Shape Selective Transport in Zeolites
{'Code': '07020000', 'Directorate': {'Abbreviation': 'ENG', 'LongName': 'Directorate For Engineering'}, 'Division': {'Abbreviation': 'CBET', 'LongName': 'Div Of Chem, Bioeng, Env, & Transp Sys'}}
{'SignBlockName': 'Robert M. Wellek'}
Effective diffusivities in zeolites show unpredictable variations               with partial pressure and temperature, sometimes exhibiting                     maxima or minima, as well as having measured diffusivities which                vary over orders of magnitude when the measurement technique is                 changed.  This project seeks to see if these discrepancies can be               resolved if we treat the sorbate in the zeolite as though it were               distributed between two states, with adsorbed species at one type               of site mobile and species adsorbed at another type of site                     immobile.  It is proposed that these two types of sorbed                        molecules, together with unabsorbed molecules in the pores of the               zeolites, make separate contributions to the observed diffusion                 coefficient, which, with their different dependencies on                        temperature, and the temperature dependence of the distribution                 of the sorbate between states, should explain the observed                      variations in diffusivities.                                                                                                                                    Zeolites are important to numerous industrial processes in which                adsorption or heterogeneous catalysis occurs.  One of the most                  important aspects of zeolites is that they are able to add                      selectivity based upon size and molecular shape to selectivity                  based upon differing affinities for the base surface of the                     zeolite material.  It should be possible to design processes                    which would take advantage of the differences in diffusivities                  within the zeolites to improve conversions or to increase                       selectivities; a better understanding of the diffusion process in               zeolites will help development in this area.  Experiments at                    carefully selected partial pressures and temperatures have been                 selected for specific sorbate molecules so that the proposed                    explanation can be tested experimentally.  These experiments will               be interpreted with the help of a mathematical model of the                     proposed transport process.
{'FirstName': 'Paul', 'LastName': 'Weisz', 'EmailAddress': None, 'StartDate': '01/01/1989', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'University of Pennsylvania', 'CityName': 'Philadelphia', 'ZipCode': '191046205', 'PhoneNumber': '2158987293', 'StreetAddress': 'Research Services', 'CountryName': 'United States', 'StateName': 'Pennsylvania', 'StateCode': 'PA'}
[{'Code': '1414', 'Text': 'INTERFAC PROCESSES & THERMODYN'}, {'Code': '1417', 'Text': 'Interfacial Engineering Progra'}]
{'url': 'https://www.nsf.gov/awardsearch/download?DownloadFileName=1988&All=true', 'xml': '8814120.xml'}