Removal of the toxic cadmium ions from aqueous solutions by zero-valent iron nanoparticles

Abstract

In this study, zero-valent iron nanoparticles (ZVINPs) were synthesized through a novel route and then used for the removal of cadmium ions from aqueous solutions. Characterization of the prepared ZVINPs nanoparticles indicated that they were the chain form of spherical ZVINPs, with an average diameter of 30 nm, in addition to magnetite impurities. The removal of Cd(II) ions from solution by ZVINPs was investigated. The optimum time for Cd(II) removal by ZVINPs in a 300 mg/L solution of water at 298 K was approximately 30 min. The removal process was endothermic. The removal was studied kinetically and the results showed that the removal of Cd(II) ions from solution by ZVINPs followed a pseudo-second-order adsorption kinetic model with a high correlation coefficient. The presence of an initial effect of bulk diffusion on film and intra-particle diffusion kinetic, implied that in addition to the first order, the second-order chemical kinetics had the presence of two paths or two reactions simultaneously. The environmental application was performed using different real water samples; and the removal reached 99.1% for the well water; 96.2% for the waste water; and 53.1% for the seawater. These results indicate the suitability of the ZVINPs for the removal of the Cd(II) from polluted water.