Studies on removal and recovery of Cr(VI) from electroplating wastes

Phosphate treated sawdust shows remarkable increase in sorption capacity of Cr(VI) as compared to untreated sawdust. The adsorption process is pH dependent. 100% adsorption of Cr(VI) was observed in the pH range <2 for the initial Cr(VI) concentration of 8–50 mg 1−1. The effect of various adsorbent doses at pH 2 confirms Langmuir adsorption isotherms. 100% removal of Cr(VI) from synthetic waste as well as from electroplating waste containing 50 mg 1−1 Cr(VI) was achieved by batch as well as by column processes. The adsorbed Cr(VI) on phosphate treated sawdust was recovered (87%) using 0.01 M sodium hydroxide.