Robust water‐stable poly (ethersulfone)/poly (ethyleneimine) nanofibrous membranes for nitrate adsorption

Abstract

Nanofibrous media or electrospun webs are widely used as affinity membranes due to their extraordinary properties. In this study, the micro‐nano structure PES/PEI membrane was fabricated by electrospinning. The stability of the membrane during adsorption and washing is very important for affinity membranes. The fabricated web was insolubilized through an optimized crosslinking reaction by glutaraldehyde. Effect of crosslinking time and concentration on adsorption efficiency of adsorbent for nitrate studied using batch experiments. The morphology of the nanofibrous web before and after crosslinking was characterized by scanning electron microscopy (SEM). Fourier transform infrared spectroscopy was used for studying the change in functional groups of PES/PEI composite. Results show that 90 min of crosslinking reaction by immersion method in 0.71% glutaraldehyde in water/acetone medium could successfully insolubilize the polyethyleneimine and change the smooth surface of the nanofibrous web to a rough state with nano spherules. The kinetics studies show that nitrate adsorption by PES/PEI composite follows a pseudo‐second‐order kinetic model. The adsorption isotherm was also investigated using Langmuir and Freundlich models. Results show that the adsorption of nitrate on PES/PEI follows the Langmuir model with a maximum adsorption capacity of 53.47 mg/g which is considered a high value comparing other studies.