Effective Copper and Methylene blue adsorption from industrial effluents onto activated carbons prepared from Rice husk ash and Hazelnut husks modified by Diopside: Equilibrium, Kinetics, and Experimental design

ABSTRACT

Activated carbon from rice husk ash (AC-RH) and hazelnut husks (AC-HH) modified by Diopside (AC-RH/Diop, AC-HH/Diop) composites were synthesised and applied for the adsorption of Copper and Methylene blue from industrial effluents. Diopside was provided by the sol-gel method and activated carbon was prepared from rice husk ash and hazelnut husks. The formation of AC/Diop composites was characterised by FT-IR, FESEM, BET, and XRD analyses. Effects of pH, amount of adsorbent, and contact time at 10 mg L⁻¹ of Copper and Methylene blue on removal percentage were studied by Box Behnken design (BBD). Optimal conditions for maximum Copper and MB by AC/Diop adsorbent (95.54% and 99.42%, respectively) were as follows: (pH = 5.45, 7.35) (adsorbent amount: 0.10, 0.45 g), and (contact time: 9.56, 13.49 min) in 20 mL of 10 mg L⁻¹ of pollutants concentration, respectively. In addition, the adsorption kinetics, thermodynamics, and isotherms were examined. Adsorption isotherms (q_max: 184.25 and 289.51 mg g⁻¹ for Copper and MB, respectively) and kinetics were demonstrated that the sorption processes were better described by the Langmuir and pseudo-second-order equation.

KEYWORDS:

• Copper
• methylene blue
• diopside
• rice husk ash
• hazelnut husks
• adsorption
• Box Behnken design

Acknowledgments

We gratefully acknowledge the financial assistance provided by the Omidiyeh Branch of Islamic Azad University.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

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