Removal of C.I. acid brown 75 from aqueous solution by kaolinite

Abstract

The adsorption of acid brown 75 onto kaolinite in aqueous solution was studied with respect to the pH, adsorbent dosage, contact time, initial concentration, and operating temperature. Desorption of dye from dye-saturated kaolinite was observed. Experimental data indicated that the adsorption capacity of kaolinite for the dye was higher in acidic rather than in basic solution. The maximum adsorption capacity of kaolinite towards the dye was found to be 96.5 mg g⁻¹ (pH 1.0). At the optimal adsorption condition, the dye removal ratio was 95.5%. Dye-saturated kaolinite could desorb at aqueous NaOH, the desorption ratio of dye was 78.8%. The linear Langmuir and Freundlich isotherm models are well fitting to represent the experimental data.

Keywords:

• C.I. acid brown 75
• kaolinite
• adsorption
• Langmuir model
• Freundlich model

Acknowledgments

We thank the Natural Science Foundation of Hebei Province (2006000969), China, for financial support.