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 MgCl 2 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 S O 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.