An efficient and reusable quaternary ammonium fabric adsorbent prepared by radiation grafting for removal of Cr(VI) from wastewater.

A novel quaternary ammonium polyethylene nonwoven fabric for removing chromium ions from water was prepared via radiation-induced grafting of glycidyl methacrylate and further modification with N,N'-dimethylethylenediamine. The structural and morphological characteristics of the adsorbent were analyzed using Fourier transform infrared spectroscopy (FTIR), thermogravimetry and differential thermogravimetry (TG/DTG), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The influences of several principal factors, including pH value, initial Cr(VI) concentration, contact time, and coexisting anions (including SO42-, CO32-, NO3-, PO43-, and Cl-), on adsorption performance were investigated via batch tests. The results showed that the optimum removal efficiency was 99.2% at pH 3 and the maximum adsorption quantity for Cr(VI) at 25 °C was 336 mg/g. The adsorption kinetic parameters were better fitted with the pseudo-second-order kinetic model, and the equilibrium data were described very well by the Freundlich isotherm model. Furthermore, the as-synthesized adsorbent exhibited excellent regeneration and recyclability while maintaining high adsorption performance after five adsorption/desorption cycles.