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Separation of polyaromatic hydrocarbons from model diesel composition via pervaporation using a fabricated aromatic polyimide membrane and process optimization

Removal of polyaromatics from diesel is important to meet automobile emission specifications. According to Worldwide Fuel Charter, the maximum allowable concentration of polyaromatic hydrocarbons (PAHs) in automotive diesel should be less than 2% vol (max). An aromatic polyimide membrane was fabricated by solution casting a mixture of polyamic acid, N,N‐dimethylacetamide and phenanthrene. This membrane was utilized for the separation of a multicomponent mixture consisting of acenaphthene and 2‐methyl naphthalene (PAHs) in toluene and n‐tetradecane, chosen as model diesel composition via pervaporation. The prepared membrane was characterized by mechanical strength testing, SEM and TGA‐DTA study. The influence of varying downstream pressure, feed composition, and operating temperature on the pervaporative separation performance in terms of combined permeation flux of the PAHs was investigated. A central composite experimental design along with response surface methodology was conducted to optimize these process factors for maximizing the combined permeation flux. The maximum value of combined permeation flux obtained was 0.071 kg m−2 h−1. Hence, it can be concluded that the novel membrane fabricated using a simple and relatively inexpensive method has good potentiality for pervaporative removal of PAHs from the chosen system. © 2018 American Institute of Chemical Engineers Environ Prog, 37: 1901–1907, 2018