Photocatalytic dye detoxification by cost-effective SnO2: Ce thin films and verification of toxicity by histology using Labeo rohita fish

Abstract

This study is aimed to provide detailed insights into the photocatalytic degradation ability of cerium-doped tin oxide (SnO₂: Ce) thin films fabricated using a cost-effective nebulizer spray pyrolysis technique. Characterization of the deposited samples was performed using XRD, SEM, EDS, E-mapping, XPS, PL and UV and the obtained results were correlated with the photocatalytic dye detoxification results. The effect of cerium doping at different concentrations (2.5, 5.0 and 7.5 wt%) on the ability of the films to break down methylene blue (MB), a toxic dye commonly found in industrial effluents was studied. The toxicity of the water treated with the doped films was evaluated by exposing freshwater fish Labeo rohita to the treated water and performing the histology study of different organs of the test fish using the paraffin wax method. The results were compared with the toxicity observed in the fish exposed to untreated methylene blue dye solution. The photocatalytic studies revealed a significant enhancement in the photocatalytic dye degrading efficiency of SnO₂ with the addition of Ce. The SnO₂: Ce (5 %) film exhibited 96.44 % decomposition of Methylene Blue (MB) dye molecules.