Modified hectorites and adsorption studies of a reactive dye

Hectorite has been modified by two different cationic surfactants namely cetyldimethyl benzylammonium chloride and cetylpyridinium chloride for the adsorption of an anionic dye, C.I. Reactive Orange 122. The modified hectorites were characterized by XRD, SEM and BET analyses. Batch experiments were carried out for the adsorption process in terms of effect of pH, adsorbent dosage, contact time, effect of salts and different dye concentrations. Experimental results show that acidic pH favours maximum colour removal. The data are well fitted by Langmuir isotherm and the adsorption capacity for cetyldimethyl benzylammonium hectorite (CDBA-hect) and cetylpyridinium hectorite (CP-hect) have been found to be 78 and 84 mg/g respectively. Kinetic studies were fitted with the pseudo-second-order kinetic model. (C) 2007 Elsevier B.V. All rights reserved.