Bio-Assisted Synthesis and Photocatalytic Performance of ZnO–Bentonite Nanocomposite in a Digital Baffle Catalytic Reactor for Organic Pollutant Removal

Document Type : Original Article

Authors

1 Chemical and Petrochemical Technology Engineering Department, Basra Engineering Technical College, Southern Technical University, Basra, Iraq

2 Department of Chemical Engineering, University of Muthanna, P.O. Box: 1550, Muthanna, Iraq

3 College of Engineering, Al Ayen University, P.O. Box: 64001, Nasiriyah, Iraq

4 Shatt Al-Arab University College, Basrah, Iraq

Abstract

In this work, a sustainable precipitation method was used to prepare a zinc oxide-bentonite clay (ZnO/BT) composite and to evaluate its catalytic performance in a digitally controlled baffle photocatalytic reactor (DBPCR) for hybrid adsorption and photo-oxidation degradation. The prepared composite was characterized using XRD, FTIR, BET, FE-SEM, and DRS to explain its structure and properties. The working parameters, including pH, process time, temperature, and dose was analyzed using a Box-Behnken design from the response surface methodology to maximize organic removal. The new reactor design provided superior mixing and light distribution, promoting combined physical and chemical treatment. The new composite achieved an excellent removal efficiency of 99.7 % for organic pollutants in refinery wastewater (RWW), compared with 90.5 % for nano clay. The results indicate that photo-oxidation degradation followed pseudo-first-order kinetics, attributed to enhanced interfacial charge transfer, reduced electron-hole recombination during photo-oxidation, and increased free radical formation. The combination of sustainable preparation with a baffled digital oxidation reactor demonstrates a viable, high-performance technique for organic remediation. This nanocomposite displays excellent stability and can be recycled over multiple cycles, more than six times, with organic removal of more than 82.5 %, emphasizing its potential for large-scale industrial applications in adsorption/ oxidation processes and ecological catalysis for wastewater treatment.

Keywords

Main Subjects

References

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