Fabrication and characterization of novel PES/Fe–Mn binary oxide UF mixed matrix membrane for adsorptive removal of As(III) from contaminated water solution

• PES/FMBO MMMs were prepared for adsorptive removal of As(III).
• The maximum As(III) adsorption capacity of the optimized MMM was 73.5 mg/g.
• The optimized MMM had a high As(III) adsorption capacity in wide pH range of 2–8.
• The membrane pure water flux was improved with the addition of FMBO particles.
• The membrane adsorption capacity could be regenerated using alkaline solution.

In this work, novel ultrafiltration (UF) mixed matrix membranes (MMMs) composed of organic polyethersulfone (PES) and inorganic Fe–Mn binary oxide (FMBO) particles were prepared through a phase inversion process for adsorptive elimination of As(III) from the contaminated water. The membranes were prepared by casting solutions that consisted of different weight ratios of FMBO to PES, in the range of 0–1.5. The membranes were then characterized with respect to crystallinity, surface roughness and morphology, using XRD, AFM and SEM, respectively. The pure water flux, hydrophilicity, porosity and As(III) adsorption capacity of the membranes were also investigated. The increase in FMBO/PES ratio resulted in an increase in membrane water flux which was attributable to the decreased contact angle, increased number of pores and greater surface roughness. Although skin layer thickness increased while pore size decreased with an increase of FMBO particles loading, the number of pores increased, which overrode the effects of the pore size and the skin layer thickness, contributing to increased water flux. The best performing membranes prepared from the FMBO/PES ratio of 1.5:1 demonstrated the pure water flux as high as 94.6 L/m2 h at operating pressure of 1 bar and maximum As(III) uptake capacity of around 73.5 mg/g. The continuous UF experiment showed that the PES/FMBO mixed matrix membrane can be potentially utilized for effective removal of As(III) from contaminated groundwater by producing permeate containing <10 μg/L As(III). As high as 87.5% of the membrane adsorption capacity could be regenerated using NaOH and NaOCl solution, showing the practicability and reusability of the membrane for As(III) removal.