Adsorption of copper(II), lead(II), and cadmium(II) ions from aqueous solution by using hydrogel with magnetic properties

Hydrogels based on acrylamide and 2-acrylamido-2-methyl-1-propanesulfonic acid were synthesized via a gamma irradiation technique and used for preparation of magnetic responsive hydrogels. The hydrogels obtained were investigated by means of X-ray diffraction, Fourier-transform infrared (FT-IR), magnetic properties, thermogravimetric analysis, and energy-dispersive X-ray analysis. The extent of adsorption was investigated as a function of pH of medium, initial metal ion concentration, and contact time. The adsorption process was well described by pseudo-second-order kinetics, and the best interpretation of the equilibrium data was given by the Freundlich isotherm. The results from sequential adsorption-desorption cycles showed that the hydrogel exhibited good desorption and reusability. It was revealed that such hydrogel networks with magnetic properties can be effectively utilized for removal of pollutants and adsorbed heavy-metal ions. The maximum adsorption capacities were 321, 436, and 470 mg g(-1) for Pb(II), Cd(II), and Cu(II) ions, respectively.