Biosorption of Auramine O and Drimarene dyes from aqueous solutions using seed powder of Diospyros lotus

Abstract

In the present study, the prospects of Diospyros lotus seed powder (DLSP) for biosorption of Auramine O and Drimarene Blue from simulated aque­ous solutions were investigated. The surface characterization was done by FTIR spectroscopy and SEM technique. The optimum conditions for adsorption of 20 ppm AO at equilibrium were found to be 0.1g of DLSP, pH 6.0–.0, 150 rpm speed for 2 hrs at 25–30 ○ C. Similarly, the effective conditions for optimal uptake of 20 ppm aqueous solution of DB were found to be 0.1g of DLSP, pH 0.0-2.0, 200 rpm speed for 2 hrs at 30 ○ C. The data followed the Langmuir, Freundlich and Temkin isotherm models but the Langmuir isotherm was the most consistent one with q m = 26.95 mgg -1 and 34.36 mgg -1 respectively for AO and DB dyes. The kinetic models showed that adsorption of DB and AO followed the pseudo second-order rate of reaction. The values of ΔG, ΔH and ΔS for AO, and DB revealed the process as an exothermic and spontaneous one. These results indicate that DLSP is a cost-effective and environment-friendly sorbent that can be used for effective removal of Auramine O and Drimarene Blue dyes from aqueous solutions.