Improved pollutant management by kinetic and Box-Behnken design analysis of HDTMA-modified bentonite's adsorption of indigo carmine dye

Abstract

The optimal performance characteristics of hexadecyltrimethylammonium-modified bentonite (HDTMA-B) for the removal of indigo carmine (IC, vat dye) from aqueous solution require a process parameter study. Using batch mode experiments and kinetic models, the study evaluated the adsorption behavior and dye-adsorbent interaction at different temperatures, adsorbent dosages, and initial dye concentrations. The rating mechanism for adsorption in ICs was found to be quite similar to the pseudo-second-order model. All of these IC dye removal adsorption parameters were optimized using a Box-Behnken surface statistical design with a pH of 6.6 as the starting point (as a fixed input parameter). At the 95% confidence level, the main effects of starting dye concentration and adsorbent dosage were both statistically significant, as was the square impact of initial dye concentration (ANOVA). There was a negative interaction between the adsorbent dose and the initial dye concentration, and this led to the discovery of a substantial detrimental effect. The primary factor in IC elimination was the initial dye concentration component (PC = 48.36%). At 34.28 °C and a starting dye concentration of 53.3 mg L-1, 0.97 g L-1 of adsorbent was optimal for removing 96.40% of IC from aqueous solutions, yielding a desirability of 1.00. The removal effectiveness of IC dye by HDTMA-modified bentonite could be predicted and the experimental parameters optimized using the simulated polynomial function. The regeneration capacity of the HDTMA-B adsorbent proves its importance in industrial wastewater treatment.