Adsorption of carmoisine A from wastewater using waste materials—Bottom ash and deoiled soya

The present study deals with the application of bottom ash, a power plant waste, and deoiled soya, an agricultural waste, for the adsorptive removal of carmoisine A dye from its aqueous solutions. This paper incorporates a comparative study of the adsorption characteristics of the dye on these effective adsorbents along with effects of time, temperature, concentration, and pH. Analytical techniques have been employed to find pore properties and characteristics of adsorbent materials. Batch adsorption studies, kinetic studies, and column operations have also been performed to understand the dye extraction ability of the adsorbents. The adsorption behavior of the dye has been studied using Freundlich, Langmuir, Tempkin, and Dubinin–Radushkevich adsorption isotherm models. The monolayer adsorption capacity determined from the Langmuir adsorption equation has been found as 1.78 × 10−5 and 5.62 × 10−5 mol g−1 at 323 K for bottom ash and deoiled soya, respectively. Kinetic measurements suggest the involvement of pseudo-second-order kinetics in both adsorptions and each case is controlled by a particle diffusion process. Column experiments demonstrated that both adsorbents could be practically utilized in elimination of hazardous dye from effluent and dye material can be recovered by eluting NaOH through the exhausted columns.

Graphical abstractEffect of amount of adsorbent on uptake of carmoisine A over bottom ash and deoiled soya at different temperatures.Figure optionsDownload full-size imageDownload as PowerPoint slide