Chromium removal by activated carbons prepared from Casurina equisetifolia leaves

Casurina equisetifolia leaves were carbonised and activated after treatment with sulphuric acid (1:1), phosphate salt (10%) or zinc chloride (25%), at different temperatures. Prepared activated carbons were used to remove Cr(VI) from wastewater and the conditions optimised for most effective carbons. The equilibrium data fitted well with the Freundlich adsorption isotherm. Desorption studies show that 65–80% of adsorbed chromium could be desorbed by alkali followed by acid treatments. Recycling of the carbons could be carried out without change in the adsorption efficiency. The carbons were also tested for the removal of chromium(VI) and total chromium from plating effluents.