Removal of Cr (VI) from plating wastewater using magnetic nanoparticles

The wastewater from plating industry usually contains high amounts of chromium. In this study, the removal of chromium (VI) from plating wastewater by magnetic Fe3O4 nanoparticles was investigated. The wastewater was obtained from a plating workshop in Paytakht Industrial Park located in Tehran, Iran. The studied nanoparticles had an average particle size of 30nm. The effects of pH, reaction time, amount of nanoparticles and temperature on the adsorption process were studied. Results showed that the optimized chromium removal could be achieved at reaction time of 60min, pH of about 3, nanoparticles amount of 1 g/L, and temperature of 25 ˚C. Moreover, the obtained data were fitted to the Langmuir and Freundlich isotherm constants to study the adsorption mechanism. Results indicated the Freundlich adsorption isotherm model was more suitable. Pseudo-firstorder and pseudo-second-order models were employed to study the adsorption kinetics, and it was found that chromium adsorption kinetics followed the second-order model.