Novel antibacterial and antifouling PES nanofiltration membrane incorporated with green synthesized nickel-bentonite nanoparticles for heavy metal ions removal

Lack of water resources and water pollution by heavy metal ions and microorganisms has made it necessary to utilize efficient water treatment methods. In this study, for the first time, nickel-bentonite nanoparticles (NBNPs) were synthesized using Scrophularia striata extract. NBNPs were used as novel nanofillers to fabricate antifouling and antibacterial NBNPs/polyethersulfone (PES) nanofiltration membranes via the phase inversion method for heavy metal ions rejection. NBNPs were characterized by FT-IR, XRD, zeta potential, EDS, FESEM, and TEM. The fabricated membranes were characterized using FT-IR, XRD, EDS, SEM, water contact angle, zeta potential, and porosity analyses.The results showed improvement of hydrophilicity, surface charge, and porosity for the modified membranes.The blended membranes had substantially less fouling and higher heavy metal ions rejection than the un-modified membrane. Pure water flux of the unfilled PES membrane was enhanced from 15 to 34.4 and 58.8 kg/m2h for 0.1 and 0.5 wt% of NBNPs, respectively. The flux recovery ratio was increased from 38.3% for the unmodified membrane to 98.2% for 0.5 wt% NBNPs/PES membrane. Also, 0.5 wt% NBNPs/PES membrane exhibited the best rejection performance (Zn2+: 98.62%, Cu2+: 97.88% and Pb2+: 97.03%). Evaluation of antibacterial properties of the membranes against Escherichia coli and Staphylococcus aureus was performed. The modified membranes had significant antibacterial capability and 1 wt% NBNPs/PES membrane exhibited the highest antibacterial rate. According to the findings, NBNPs could be used as nanofillers to fabricate modified nanofiltration membranes for heavy metal ions rejection and antibacterial ability.

Automated summary

In this study, nickel-bentonite nanoparticles were synthesized using Scrophularia striata extract and used as nanofillers for fabricating antifouling and antibacterial nanofiltration membranes. The modified membranes showed improved hydrophilicity, surface charge, and porosity, resulting in reduced fouling and higher rejection of heavy metal ions. The membranes also exhibited significant antibacterial capability, with 1 wt% NBNPs/PES membrane showing the highest antibacterial rate.