Box-Behnken Design for Optimizing Synthesis and Adsorption Conditions of Covalently Crosslinked Chitosan/Coal Fly Ash Composite for Reactive Red 120 Dye Removal

In this research, a biocomposite adsorbent of covalently crosslinked chitosan-epichlorohydrin/coal fly ash (CHT-ECH/CFA) was synthesized and applied for reactive red 120 dye (RR120) removal. The CHT-ECH/CFA was characterized by BET, pH potentiometric, pH(pzc), XRD, FTIR and SEM-EDX. A statistical optimization by Box-Behnken Design (BBD) was employed to assess the effects of the adsorption key parameters such as CFA loading into CTH-ECH matrix, adsorbent dose, solution pH, working temperature and contact time. The optimized CFA loading, adsorbent dose, temperature, time, and pH were observed to be 50%, 0.07 g, 45 degrees C, 60 min, and solution pH 4 respectively. From BBD, the highest removal of RR120 at optimum operation conditions was found to be 90.2%. The experimental results show the adsorption process can be perfectly described by both Langmuir and Freundlich isotherm models with maximum adsorption capacity of 237.7 mg/g at 45 degrees C. Moreover, the adsorption kinetics were well fitted to the pseudo-second order model. This research introduces a new hybrid biocomposite adsorbent with potential application for the treatment of anionic dye-polluted water.

Automated summary

In this research, a new hybrid biocomposite adsorbent was synthesized and applied for the removal of reactive red 120 dye. The adsorption process was optimized using statistical optimization method, and the adsorbent showed high adsorption capacity and removal efficiency. The results indicate that the adsorbent has potential application for the treatment of anionic dye-polluted water.