Embedding low-cost 1D and 2D iron pillared nanoclay to enhance the stability of polyethersulfone membranes for the removal of bisphenol A from water

A novel polyethersulfone (PES) mixed matrix membranes (MMMs) loaded with iron (Fe) pillared nanoclay was fabricated for efficient rejection of bisphenol A (BPA) from water. Low-cost one dimensional (1D) pillared halloysite (FePHNTs), two dimensional (2D) pillared bentonite (FePB), and 2D pillared Cloisite 15A (FePC15A) were synthesized via pillaring procedure. XRD, TEM, EDS and BET results indicated that the nanoclays were successfully pillared. Pillared nanoclay was loaded into the MMMs at different loading percentages using phase inversion fabrication technique. Existence of iron pillared nanoclay within MMMs significantly enhanced hydrophilicity, stability and water flux than the pristine PES (Y0) membrane. 0.5 wt% of 2D FePB loaded Y4 MMMs exhibited higher BPA rejection at pH = 9. This was attributed to activated surface of MMMs loaded with 2D FePB than the 1D FeHNTs and 2D FePC15A loaded MMMs. The electrostatic repulsion between dissociated BPA and negatively charged FePB enhanced rejection. The effect of operating pressure and BPA concentration on BPA rejection of Y4 MMMs was better than the Y0 membrane. Further, the influence of humic acid on BPA rejection experiments confirmed a significant improvement in the BPA rejection efficiency of 69.5% for Y4 MMMs. Overall, Y4 MMMs with 2D FePB displayed excellent membrane performance and potential for water treatment applications.