Removal of acid yellow-17 dye from aqueous solution using eco-friendly biosorbent

Abstract

Dyes are usually present in trace quantities in the treated effluents of many industries. The effectiveness of adsorption for dye removal from wastewaters has made it an ideal alternative to other expensive treatment methods. Biosorption of acid yellow (AY17), a monoazo acid dye, was investigated using Typha angustata L. as biosorbent in a batch system with respect to initial pH, temperature, initial dye concentration, biosorbent dosage, and contact time. The biomass exhibited the highest dye uptake capacity at 303 K, initial pH value of 2, the initial dye concentration of 150 mg/L, biosorbent dosage of 0.5 g and contact time of 40 min. The extent of dye removal increased with increase in time, biosorbent dosage and decreased with increase in temperature. The equilibrium sorption capacity of the biomass increased on increasing the initial dye concentration up to 150 mg/L and then started decreasing in the studied concentration up to 600 mg/L. The experimental results have shown that the acidic pH favors the biosorption. Langmuir and Freundlich adsorption model is used for the mathematical description of the biosorption equilibrium and isotherm constants are evaluated at different temperatures. Equilibrium data fitted very well to the Freundlich model in the studied concentration (25–600 mg/L) and temperature (303–323 K) ranges. The pseudo-first- and second-order kinetic models were also applied to the experimental data. The results indicated that the dye uptake process followed the pseudo-second-order rate expression and the adsorption rate constants increased with increasing concentration. The adsorption results in this study indicated that all the adsorbents were attractive candidates for removing acidic dyes from dye wastewater.