Recycling of industrial solid waste for the removal of mercury(II) by adsorption process

Fe(III)/Cr(III) hydroxide, a waste byproduct obtained from the treatment of Cr(VI) containing wastewaters in a fertilizer industry, has been used for the adsorption of Hg(II) from aqueous solution. The influence of various parameters such as metal ion concentration (10 - 40 mg/L), agitation time (1 - 180 sin), adsorbent dosage (5 - 250 mg per 50 al), temperature (24 - 44 degrees C) and ph value (4 - 10) on the removal of Hg(II) has been studied. The adsorption follows both Langmuir and Freundlich isotherm models. The applicability of the Lagergren kinetic model has been investigated. Almost quantitative removal of Hg(II) from a solution containing 40 mg/L in a 50 al solution by 175 mg of adsorbent occurred at an initial ph of 5.8. Adsorption vas uniformaly high (91 %) in the initial ph range 4.0 to 10.0. Temperature studies shoved that the adsorption process vas endothermic in nature. Desorption of Hg(II) shoved that it is solubilised in 2 % KI to the extent of 85 %. (C) 1997 Elsevier Science Ltd.