Synthesis of SnO₂ Nanoparticles by Microwave-Assisted Hydrothermal Method for the Photodegradation of Congo Red Dye

Abstract

Textile dyes are widely used in manufacturing processes and are often discharged as untreated wastewater, leading to environmental contamination. Congo Red is one of the most commonly found azo dyes in textile effluents and is highly resistant to conventional treatments. Photodegradation offers an environmentally friendly alternative by utilizing semiconductor-based photocatalysts. In this study, tin oxide nanoparticles were synthesized via a microwave-assisted hydrothermal method with different heating durations to determine the optimum reaction time. The nanoparticles were characterized using X-ray diffraction and applied for Congo Red removal through adsorption followed by photocatalytic degradation, with persulfate ions used as electron scavengers. The results indicate that the microwave-assisted method successfully produced tin oxide nanoparticles with optimal performance at a synthesis duration of four hours. The material exhibited a tetragonal structure with a crystallite size of 8.1 nm and an optical band gap of 3.04 eV. Congo Red removal through adsorption reached 11.11%, while photocatalytic treatment achieved 74.67%, and further increased to 98.64% with the addition of persulfate. These findings demonstrate the potential of microwave-assited hydrothermal derived tin oxide nanoparticles for efficient dye removal in wastewater treatment.