Improving the wastewater treatment performance of loose nano-filtration membranes using natural clay functionalized with AlFe2O4 nanocleaners

Abstract

Membranes with the right composition can potentially afford exceptionally high water flux with high contaminant rejection and recovery ratios, prolonged life with anti-fouling capabilities, and low operating costs. In this regard, an innovative AlFe₂O₄-functionalized bentonite (AlFe₂O₄@BT) material was prepared as a performance-boosting agent for polyethersulfone (PES)-based mixed-matrix loose nanofiltration membranes (LNMs). Herein, the fabrication of PES-based mixed matrices was achieved by blending AlFe₂O₄@BT at different wt% values through phase inversion technology. The effects of AlFe₂O₄@BT on the structure and functionality of the as-prepared AlFe₂O₄@BT-PES LNMs were thoroughly examined by scanning electron microscopy, contact angle measurements, antifouling measurements and other techniques. The separation efficiency of the AlFe₂O₄@BT-PES-based LNMs was recorded as 80%, 85% and 95% for crystal violet (CV), Congo Red (CR), and humic acid, respectively, with exceptionally high product flux efficiencies and anti-fouling properties comparable to those of commercial polyamide membranes. The new LNMs operate at relatively low operating pressures (1–4 bar), thus offering sustainable separation processes with lower flux decline ratios and high recovery ratios, demonstrating their superior membrane material combination.