Janus membrane prepared via one step depositing coatings onto PVDF/PDMS membrane for simultaneous antiwetting and antifouling in DCMD

Abstract

A Janus membrane with antiwetting and antifouling properties was prepared for complicated wastewater treatment via direct contact membrane distillation (DCMD) technology. The membrane was fabricated by directly depositing gallic acid (GA) and polyethyleneimine (PEI) onto one side of the PVDF/polydimethylsiloxane (PDMS) blend membrane. The results from different characterization methods demonstrate the successful fabrication of the Janus membrane. The obtained Janus membrane performs excellent antiwetting and antifouling properties because of its asymmetric wettability. When the 36 h DCMD test was carried out using the Janus membrane to treat feed solution containing 1000 mg/L crude oil, 0.3 mM SDS and 3.5 wt% NaCl, a relatively stable flux of 15.7 ± 0.2 Kg·m−2·h−1 was maintained, as well as the very small conductivity of 0.3 ± 0.0 μS/cm in the permeate side was kept. In addition, the as-prepared Janus membrane maintained stable when pH ranged from 1.0 to 11.0. Therefore, this Janus membrane can be a strong candidate in DCMD process to treat wastewater containing complicated contaminants.