A negatively charged polyethersulfone nanofiltration membrane enriched with Ag-functionalized titanium silicon carbide for the removal of organic pollutants from water

Abstract

Developing high-performance nanofiltration membranes for treating wastewater contaminated with organic pollutants requires special attention. The toxic nature and side effects of organic pollutants, such as dyes and antibiotics, make them hazardous. Therefore, wastewater containing organic pollutants must be treated properly before entering water environments. Herein, we synthesized the Ti3SiC2 MAX phase via the reactive sintering technique. To make the Ti3SiC2 more hydrophilic and compatible with the polyethersulfone (PES) membrane, its surface was modified in one step with Ag NPs/polyvinyl alcohol (Ag-MAX). Different quantities (0–1 wt%) of Ag-MAX filler were embedded into the PES membrane via the phase inversion process. The presence of 0.75 wt% Ag-MAX filler enhanced hydrophilicity, porosity, surface roughness, pore size, and negative charge of PES membrane, which are beneficial for permeance and antifouling features of Ag-MAX mixed matrix membranes (MMMs). The optimized membrane containing 0.75 wt% of Ag-MAX demonstrated the uppermost pure water flux of 72.5 L/m2 h with a flux recovery ratio of 82.8 %. The optimized membrane showed rejection efficiency of 99.4, 99.6, and 99.7 % for Direct Black 38, Acid Blue 113, and Disperse Red 153 dye solutions, along with a satisfactory rejection of 70.7, 65.9, and 58.5 % for Basic Violet 1, Alizarin Red S, and Ceftriaxone solutions, respectively. Furthermore, the effects of various pH values, various salt types, and cyclic filtration experiments on the separation performance of 0.75 wt% Ag-MAX MMM were investigated. The rejection efficiency was 0.75 wt% Ag-MAX MMM toward Acid Blue 113 is almost constant and higher than 98.5 % in different conditions, demonstrating that the Ag-MAX MMM could be a suitable candidate for the treatment of wastewater contaminated with organic pollutants.