Optimization of photocatalytic degradation of sulphonated diazo dye C.I. Reactive Green 19 using ceramic-coated TiO₂ nanoparticles

Abstract

Optimization of photocatalytic degradation of C.I. Reactive Green 19 (RG19) under UV light irradiation using ceramic-coated TiO₂ nanoparticles in a continuous circulation rectangular photoreactor was studied. The used catalyst was TiO₂ Millennium PC-500 (crystallite mean size 8 nm) immobilized on ceramic plates. A central composite design was used for optimization of the UV/TiO₂ process. Predicted values of decolorization efficiency were found to be in good agreement with experimental values (R ²=0.97 and Adj-R ²=0.91). Optimization results showed that maximum decolorization efficiency was achieved at the optimum conditions of: initial dye concentration 10 mg/L, UV light intensity 47.2 W/m², flow rate 150 mL/min and reaction time 240 min. Photocatalytic mineralization of RG19 was monitored by chemical oxygen demand (COD) decrease and changes in the UV–Vis spectrum.

Keywords:

• TiO₂ nanoparticles
• photodegradation
• immobilization
• ceramic plates
• response surface methodology

Acknowledgements

The authors thank the Water and Wastewater Company of East Azerbaijan for financial support. The authors also wish to thank the University of Tabriz for all the support provided.