Adsorption of Basic Blue 41 textile dye from aqueous solutions using raw and activated termite mound: Box–Behnken optimization, kinetic, and isotherm modeling

ABSTRACT This study aimed to investigate Basic Blue 41 dye adsorption potential of termite mound from an aqueous solution to develop affordable and efficient treatment technologies for textile and dye industries. Raw termite mound (R-TM) and heat-treated termite mound (H-TM) underwent characterization through FTIR, XRD, SEM, and BET techniques. Their adsorption performances were assessed in batch modes; and parameters (initial dye concentration, adsorbent amount, contact time, and temperature at constant pH 5) were optimized based on the Box–Behnken design. According to the value of correlation coefficients of the quadratic model, predicted values were highly correlated with experimental data for R-TM (R2 = 0.941) and H-TM (R2 = 0.983), respectively. Under optimized conditions, the removal efficiencies of R-TM and H-TM were 89.72% and 96.99%, respectively. Langmuir isotherm best described their adsorption equilibrium, with maximum monolayer adsorption capacities of 18.48 and 26.25 mgg−1 for R-TM and H-TM, respectively. Pseudo-second-order kinetic model was the best fit for the experimental data of both R-TM and H-TM. Regeneration of dye-loaded adsorbent was effectively done with NaOH solution with insignificant dye loss. The study found that R-TM and H-TM could be effective adsorbents for removing dye from textile wastewater through adsorption.