RECYCLING OF INDUSTRIAL SOLID-WASTE FOR THE REMOVAL OF MERCURY(II) BYADSORPTION PROCESS

Fe(III)/Cr(III) hydroxide, a waste byproduct obtained from the treatme nt of Cr(VI) containing wastewaters in a fertilizer industry, has been used for the adsorption of Hg(II) from aqueous solution. The influenc e 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 remova l of Hg(II) has been studied. The adsorption follows both Langmuir and Freundlich isotherm models. The applicability of the Lagergren kineti c model has been investigated. Almost quantitative removal of Hg(II) f rom a solution containing 40 mg/L in a 50 al solution by 175 mg of ads orbent occurred at an initial ph of 5.8. Adsorption vas uniformaly hig h (91 %) in the initial ph range 4.0 to 10.0. Temperature studies shov ed that the adsorption process vas endothermic in nature. Desorption o f Hg(II) shoved that it is solubilised in 2 % KI to the extent of 85 % . (C) 1997 Elsevier Science Ltd.