Adsorption of malachite green onto sodium alginate/bentonite (SA/Bnt) nanocomposite: optimization and modeling via RSM-DSD and insight kinetics and mechanism of adsorption

Malachite green (MG) is extensively used in various industries including the food sector, despite having carcinogenic, mutagenic, and teratogenic effects. In the present study, sodium alginate/bentonite (SA/Bnt) nanocomposite was synthesized and characterized to evaluate its potential as an adsorbent to remove MG dye from aqueous solution. The response surface method (RSM) was utilized to optimize the process, and the kinetics of adsorption were evaluated based on experiments carried out thereon. The first-order model was shown to have a decent connection between some parameters and the outcome in this experimental situation. ANOVA results showed that only three of the five parameters (MG dye concentration, contact time, and adsorbent dosage) were important in the removal of the dye. The process parameters such as dye concentration (10–50 mg L⁻¹), contact time (10–60 min), adsorbent dosage (0.5–1.5 g L⁻¹), pH (3–8), and temperature (25–55 °C) were optimized to achieve maximum dye removal, which was around 96%. The correlation of pseudo-second-order kinetic was found to be best fitted with adsorption data with an R² value of 1.00. The synthesized nanocomposites were found to be effective as bio-adsorbent agents.