Carboxymethyl cellulose-hydrogel embedded with modified magnetite nanoparticles and porous carbon: Effective environmental adsorbent

Adsorption is the most efficient technique for the removal of metal ions and organic dyes from water. This stimulates demand for the preparation of eco-friendly adsorbents. In this study, magnetic hydrogels based on a crosslinked carboxymethyl cellulose grafted acrylamide (CMC-g-AM) embedded with porous carbon (PC) and citric acid-modified magnetite were prepared. PC was synthesized via single-step oxidation of bagasse under muffled atmosphere condition. The magnetite (Fe3O4) nanoparticles were synthesized using the co-precipitation method (Fe2+/Fe3+) and citric acid modification (CFe). Functionality and parameters of adsorbent were characterized by infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray. The magnetic hydrogels have a highly effective performance for Pb-ions and methylene blue dye (MB) removal from water due to the unique role of crosslinked CMC matrix in supporting synergy between embedded PC and CFe. Adsorption testing using time intervals (5-120 min) and Pb-ions and MB concentrations (5-500 mg/L) indicate that CMC-g-AM containing equal content of PC and CFe has substantially higher removal efficiency; 70.8 and 96.1 % against 47.8 and 30.2 % (without PC and CFe) for Pb-ions and MB adsorption respectively for CMC-g-AM. The equilibrium time and the maximum sorption capacity (qm) from the adsorption studies were found to be 60 and 30 min and 294.1 and 222.2 mg/g for Pb-ions and MB respectively. The kinetics and isotherms were studied to highlight the adsorption rate and mechanism of the adsorption process.