Recovery of 1-ethyl-2-methylbenzene from wastewater by polymeric membranes via pervaporation process

Abstract

In the present study for the first time, recovery of 1-ethyl-2-methylbenzene from aqueous solution was investigated by pervaporation process with polymeric membranes containing ethylene propylene diene monomer (EPDM), poly dimethylsiloxane (PDMS), poly vinylidenefluoride (PVDF) and poly ether-block-amide (PEBA). After preparation of membranes by solution casting method, the membranes were applied in pervaporation experiments at ambient temperature to determine several parameters such as flux, separation factor and pervaporation separation index (PSI). Scanning electron microscopy (SEM), contact angle, mechanical resistance and degree of swelling analyses were performed to characterize the prepared membranes. SEM images showed a dense and symmetrical morphology in regard to the prepared membranes. Results of contact angle analysis indicated that PDMS and EPDM membranes were completely hydrophobic in comparison with the other prepared membranes. Percent of swelling for all membranes was rather low and all of them swelled lower than 3.5%; however, swelling value for PVDF membrane was approximately negligible (0.3%). EPDM membrane with PSI value of of 653 kg/m2.h and separation factor of 3558, showed a superior performance in pervaporation process compared to the other prepared membranes; however, this membrane presented lower mechanical strength than the other membranes. PVDF membrane showed better results in terms of mechanical strength compared to the other membranes. Considering pervaporation separation index of 248 kg/m2.h and separation factor of 480, which were better than that of PDMS and PEBA membranes, PVDF showed poor performance in PV process compared with EPDM membrane. According to the higher mechanical strength and slight willingness of PVDF membrane to swelling in contact with aqueous feed, performance enhancement of this membrane in the pervaporation process can greatly surpass its position in removing 1-ethyl-2-methylbenzene from contaminated water.