Functionalized Cellulosic Fibers for Removal of Toxic Metal Ions From Contaminated Water

Functionalization of cellulosic okra fibers was carried out by graft copolymerization of acrylamide in the presence of ascorbic acid and hydrogen peroxide as redox initiator in aqueous medium. Different reaction parameters such as time, temperature, initiator concentration, and monomer concentration were optimized to obtain the maximum graft yield. The graft copolymerized fibers were characterized by FT-IR, TGA, and X-ray diffraction techniques. Further, chemically modified fibers were used for removal of Zn²⁺ and Cd²⁺ toxic metal ions from contaminated water. The effect of pH, contact time, and metal ion concentration was studied in batch mode experiments. The kinetics of adsorption were studied using pseudo-first and pseudo-second-order kinetic models. The adsorption isotherm was studied using Langmuir and Freundlich isotherm models. The Langmuir model was found to fit the equilibrium data well.