Revolutionary dual nanofiller embedded nanofiltration membranes: fabricated CQDs and PMO-PPD modified membranes for experimental design optimization of simultaneous removal of Pb(ii), MO, and NaCl from wastewater†

Abstract

This study introduces a revolutionary nanofiltration membrane capable of significantly enhancing the removal of Pb(II), MO, and NaCl from industrial wastewater. The performance of polyethersulfone (PES) membranes was enhanced by incorporating PMO-PPD and CQD nanomaterials. The composite membranes demonstrated improved hydrophilic properties, reduced fouling, enhanced antibacterial activity, and increased pollutant removal capabilities. Characterization techniques confirmed the successful synthesis and integration of the nanomaterials into the membrane matrix. The inclusion of PMO-PPD/CQDs significantly improved pure water flux and fouling resistance compared to pristine PES membranes. The M3 membrane, containing 0.1 wt% PMO-PPD and 0.4 wt% CQDs nanofiller, exhibited the highest performance in terms of water flux (81.3 L m⁻² h⁻¹), bovine serum albumin rejection (29.5 L m⁻² h⁻¹), foul resistance ratio (63.7%), total resistance (58%), reversible resistance (21.6%), and irreversible resistance (36.3%). Among fabricated membranes, M3 demonstrated the highest pollutant removal rates, reaching 89.76%, 93.7%, and 36.77% for Pb(II) (initial concentration of 30 mg L⁻¹), methyl orange (MO) (initial concentration of 40 mg L⁻¹), and NaCl (initial concentration of 200 mg L⁻¹), respectively. Response surface methodology was employed to optimize the simultaneous removal of these pollutants. Additionally, the incorporation of CQDs enhanced the antibacterial properties of the membranes against E. coli (17.99%) and S. aureus (22.70%). It was found that the simultaneous application of two nanofillers significantly enhanced the efficiency and features of the nanofiltration membrane.