Biosorption of acid dyes from aqueous solution using Curcuma angustifolia scales

The presence of even a very small quantity of dye in water bodies is undesirable and affects the water bodies. Dye removal from industrial waste water is significant; hence in this study, a material that is an economical waste product was employed to test its acid dye removing capacity from aqueous solution.
In this study, batch mode experiments were performed in the sorption process of Acid Red 97 (AR 97), Acid Red 114 (AR 114) and Acid Red 151 (AR 151) onto Curcuma angustifolia scales (CS). Also, the effect of process parameters like pH and adsorbent dosage was studied. The experimental data of AR 97, AR 114 and AR 151 sorption was fitted to Langmuir, Freundlich and Temkin isotherm models. Kinetic results in AR 97, AR 114 and AR 151 sorption were fitted at various concentrations to pseudo-first order, pseudo-second order, Elovich and Intra-particle diffusion model.
The monolayer sorption capacity of the acid dyes was found to be AR 97 (350.87 mg/g), AR 114 (202.42 mg/g) and AR 151 (168.91 mg/g). The Pseudo-second order model proved to be the best fit for the acid dyes. Boyd plot, confirms film diffusion in all acid dye sorption processes.
The results showed higher dye removal for acid dyes at pH 2. The isotherm data, demonstrated good sorption capacity with AR 97>AR 114>AR 151. Employing the CS material in this study proves to be a potential alternative to costlier adsorbents, utilized for the treatment of dye containing industrial waste water.