Activation of Polyethylene/Polypropylene Nonwoven Fabric by Radiation-Induced Grafting for the Removal of Cr(VI) from Aqueous Solutions

Cr(VI) adsorption onto a novel fibrous ethylenediamine-functionalized polyethylene/polypropylene (PE/PP-g-PGMA-EDA) nonwoven fabric was investigated in aqueous solutions. The ethylenediamine functionalities were immobilized on the PE/PP nonwoven fabric through the epoxy groups of poly(glycidyl methacrylate) (PGMA) grafted to the fibers via radiation-induced emulsion graft polymerization in aqueous solution. Optimum conditions for grafting and subsequent modification steps were determined. The adsorbents were characterized by FTIR, XPS, and SEM techniques. Cr(VI) adsorption was studied in batch mode as a function of pH, feed concentration, contact time, ionic strength, and coexisting anions. The nonwoven adsorbent exhibited efficient, rapid Cr(VI) removal; high adsorption capacity; and insignificant interference from coexisting ions. Adsorbed Cr(VI) ions were desorbed using 2 M HNO3 solution, and the adsorption capacity of the nonwoven fabric was retained for four adsorption-desorption cycles. The data for Cr(VI) adsorption on the nonwoven fabric fitted to the Langmuir isotherm model well. The maximum adsorption capacity for the Langmuir isotherm was 178.9 mg Cr(VI)/g polymer at pH 3.00.