REMOVAL OF CONGO RED FROM WASTE-WATER BY ADSORPTION ONTO WASTE RED MUD

Waste red mud, an industrial byproduct, generated during the processin g of bauxite ore, is recycled for the adsorption of congo red from aqu eous solution. Adsorption kinetics were studied using the parameters s uch as dye concentration, adsorbent dose, agitation time and pH. Adsor ption followed first rate expression. The equilibrium adsorption data obeyed both Langmuir and Freundlich isotherms. The adsorption capacity of the red mud for the dye was 4.05 mg/g. Adsorption was found to be nearly quantitative at pH 2.0. Effect of pH and desorption studies sug gest that the mechanism of adsorption is mostly ion exchange. (C) 1997 Elsevier Science Ltd.