Vanadium removal from water by waste metal sludge and cement immobilization

The present study was first carried out to investigate the adsorption potential of metal sludge (a waste product of electroplating industry) in removing vanadium from water. The adsorption capacity of metal sludge for vanadium was found 24.8 mg/g at 25 degrees C. The adsorption was studied as a function of contact time (0.5-10 h), concentration (1.5 x 10(-4)-9.5 x 10(-4) M) and temperature (25 and 45 degrees C) by batch method. The adsorption has been found to be endothermic and data conform to Langmuir model. The analysis of kinetic data indicates that present adsorption system is a pseudo-first-order process and intraparticle diffusion controlled. After adsorption studies, the metal-laden sludge adsorbent was immobilized into the cement for its ultimate disposal. Physical properties such as initial and final setting time, compressive strength of cement stabilized wastes were tested to see the effect of metal-laden sludge in cement. The results of present study clearly reveal that metal sludge can be fruitfully employed in treating industrial effluents containing vanadium and further safely dispose of by immobilizing it into cement. The proposed technology provides a two-fold advantage of wastewater treatment and solid waste management. (C) 2008 Elsevier B.V. All rights reserved.