Removal of arsenic from water using a novel polyamide composite hollow fiber membrane by interfacial polymerization on lumen side

A novel mixed polyamide based composite membrane was prepared by interfacial polymerization (IP) of chitosan (CS) and m-phenylenediamine (MPD) mixture with trimesoyl chloride (TMC) for low pressure hollow fiber nanofiltration (NF). A uniform thin selective layer of polyamide was chemically coated on the lumen side of the polysulfone (PSF) based ultrafiltration support membrane. Permeability of the prepared hollow fiber NF membrane improved appreciably by incorporation of a small amount of CS into the MPD solution during IP process. The properties of prepared hollow fiber membranes were characterized using scanning electron microscope (SEM), contact angle, molecular weight cut off (MWCO), permeability, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and surface zeta potential. Pure water permeability of mixed polyamide composite membrane enhanced from 3.8 l/m 2 h bar to 32.5 l/m 2 h bar, which corroborated an increase in MWCO from 673 Da to 2553 Da and pore radius from 6.8 to 12.9 Å as CS was incorporated in polyamide layer. However, this drastic increase in permeate flux was not compromised with the arsenate rejection, which changed from 74.68% to 73.16% only. Thus, the prepared hollow fiber membrane performance was suitable and competent for low pressure driven hollow fiber membrane based arsenate rejection, which has many advantages over the conventional resin based filtration to remove arsenic from water. Performance of the developed hollow fiber membrane was also tested with arsenic contaminated natural groundwater prepared artificially with a rejection of 66–71% arsenate, 45–47% total dissolved solids (TDS), 47–48% hardness and 46–50% iron at 1 bar pressure with 25 l/m 2 h permeate flux. • Arsenic selective hollow fiber membranes synthesized. • Incorporation of chitosan in polyamide layer increased permeate flux significantly. • MWCO increased from 673 Da to 2553 Da and pore radius from 6.8 to 12.9 Å as chitosan was incorporated in polyamide layer. • The membrane was capable to remove 66–71% arsenate, 45–47% TDS, 47–48% hardness and 46–50% iron from natural groundwater. • The membrane characterization has shown the modified chemical structure of polyamide.