Improvement in heavy metal removal from aqueous solution using polyetherimide nanofiltration membrane modified by coating approach

This research focused on improving the antifouling properties and rejection performance of polyetherimide (PEI) nanofiltration membrane by chemical surface modification (surface coating). The hydrophilicity of the PEI nanofiltration membrane’s surface was enhanced by anchoring guanidine on its surface which the used dosage of guanidine wasconsidered as a variable (۰.۵, ۱, and ۱.۵ g/L of guanidine concentration). ATR-FTIR, SEM, AFM, and water contact angle were used to characterize the surface-modified membranes. Also, dry milk powder solution was considered as an organic foulant to assess antifouling features of the fabricated membranes. According to the obtained results, the surface modified membrane with ۰.۵ g/L of guanidine concentration was the optimal surface-modified membrane with pure water flux (PWF) and flux recovery ratio (FRR) of ۱۱.۶ kg/m۲.h and ۸۸.۸%, respectively. Moreover, the capabilities of the optimal surface-modified membrane and the pristine membrane for rejecting AS۵+ and Hg۲+ in aqueous solution with concentrations of ۲۰ ppm and ۵۰ mg/L were compared. Based on the obtained results, the optimal surface-modified membrane rejected more than ۹۸.۵ % of AS۵+ and Hg۲+ solutions with ۲۰ and ۵۰ mg/L of metal ion concentrations.

Keywords:

Polyetherimide , Surface modification , Guanidine , Heavy metal ions