3, 3′-diaminodiphenyl sulfone engagement in polysulfonamide-based acid-resistant nanofiltration membrane fabrication for efficient separation performance and heavy metal ions removal from wastewater

The desirability of acid-resistant nanofiltration (NF) membranes having superior acid stability with good separation performance for industrial acid wastewater treatment and reclamation is currently in high demand. Here, we presented a new sulfonated-based acid-resistant NF membrane prepared by the crosslinking and participation action of 3,3′-diaminodiphenyl sulfone (DDS) via the synthesis of branched polyethyleneimine (BPEI) and 1,3-benzenedisulfonyl chloride (BDSC). By optimizing the preparation conditions, the BP-DDS/BD membrane exhibited an improved pure water flux of 13.4 L m−2 h−1 bar−1 and a MgCl2 rejection of 97.3% for 1000 ppm. It also shows desirable rejection (>90%) and adsorption capacities for selected heavy metals. In addition, an excellent pressure resistance at different operating bars was achieved. Benefiting from the strong and stable SO bond present in DDS, the optimized BP-DDS/BD membrane displayed an outstanding acid stability at different acid immersion conditions while also maintaining impressive long-term stability of 240 h after 30 days acid exposure period. The polysulfonamide (PSA)-based NF membrane presented in this work therefore demonstrated viable and promising usefulness in wastewater treatment containing acid and heavy metal ions removal.