Chitosan-triphosphate/food Grade Algae/montmorillonite Clay for Adsorptive Removal of Methyl Violet 2B Dye Removal: Behnken Design Optimization

In this study, a cross-linked chitosan tripolyphosphate (CS-TPP) was modified by food-grade algae (FGA) and montmorillonite clay (MMT) with assistance of hydrothermal process to produce a biocomposite adsorbent (CS-TPP/FGA/MMT). The effectiveness of CS-TPP/FGA/MMT was evaluated towards removal of toxic cationic dye (methyl violet 2B (MV 2B)) from aqueous environment. The key factors affecting adsorption, namely (A) CS-TPP/FGA/MMT dosage (0.02–0.1 g/100 mL); (B) pH (4–10); and (C) time (10–60 min) were optimized using the Box-Behnken design (BBD). The desirability function test confirmed the desirable conditions of the adsorption key parameters and identified as CS-PVA/FGA/MMT dosage of 0.09 g/100 mL solution pH of 7.7 and time 59 min. The adsorption kinetic and isotherm were well explained by pseudo-second-order (PSO) and Langmuir isotherm model respectively. The maximum adsorption capacity (qmax) of CS-TPP/FGA/MMT for removing MV 2B was determined to be 165.9 mg/g at 25C°. The proposed MV 2B adsorption mechanism by CS-TPP/FGA/MMT can be assigned to electrostatic forces, n-π stacking, and H bonding. The findings of this study suggest that CS-TPP/FGA/MMT can effectively be applied for removal of toxic organic cationic dyes from aqueous solution.