Activated Clay as an Adsorbent for Cationic Dyestuffs

Abstract

The adsorption of cationic dyestuffs (Basic Blue 69 and Basic Red 22) from aqueous solution by natural and activated clays has been investigated. The maximum adsorption capacity (q max ) of BB 69 and BR 22 on to natural clay was 390 mg/g and 365 mg/g, respectively. The natural clay was treated with H 2 O 2 and HCl to enhance its adsorption capacity for dyestuffs. The efficiency of activation with H 2 O 2 was greater by a factor of 23% and 13% in the case of BB 69 and BR 22, respectively, when compared with natural clay. The efficiency of activation with HCl was superior by 30% and 16% in the case of BB 69 and BR 22, respectively, relative to natural clay. The adsorption capacity has been correlated with the pore structure and the surface charge. The results obtained show that the adsorption capacity is independent of the S BET values but depends on the surface charge.