Enhancing the adsorption capacities of acid dyes by chitosan nano particles

In the present study, nanochitosan emulsion has been produced in a suspension form by adding tripolyphosphate solution into a chitosan solution drop-wise. The adsorption capacities of four acid dyes, namely, Acid Orange 10 (AO10), Acid Orange 12 (AO12), Acid Red 18 (AR18) and Acid Red 73 (AR73) on nanochitosan, have been determined to be 1.77, 4.33. 1.37 and 2.13 mmol l(-1), respectively. The nanochitosan dye capacities were compared with normal chitosan capacities which were 1.54, 2.66, 1.11 and 1.25 mmol l(-1) for AO10, A012, AR18 and AR73, respectively. In all cases, the nanochitosan has a higher capacity. The mechanism of acid dye adsorption and the effect of pH are also discussed. (c) 2008 Elsevier Ltd. All rights reserved.