Bio-inspired hybrid coating of microporous polyethersulfone membranes by one-step deposition of polydopamine embedded with amino-functionalized SiO2 for high-efficiency oily wastewater treatment

Oily wastewater treatment has turned out to be a big menace due to complexity, existence of surfactant/oil-including water, and growth of originating industries. Superhydrophilic surfaces due to higher water permeability, under-water superoleophobicity, and better fouling resistance than typical hydrophilic membranes are in the center of attention. In the present study, a neat polyethersulfone (PES) membrane was fabricated using non-solvent induced phase separation - vapor induced phase separation (NIPS-VIPS) processes and then was modified using facile amino-functionalization of SiO2 in the presence of polydopamine (PDA). Symmetric PES membrane hydrophilicity was improved from 44.6 to 11.3º after a surface modification. Permeate flux of the neat NIPS-VIPS and the well-modified membrane were measured as 511 and 1836 L/m2 h bar, respectively. The oil rejection factor was higher than 98% using all tested membranes. Furthermore, irreversible fouling (Rir) was reduced from 18.0% to 2.5% for the neat NIPS-VIPS and well-modified PES membranes, respectively. Considering these attributes, our study can pave the way to fabricate more robust membranes with superior anti-fouling properties to deal with the rising threat of oily water production.