An Analysis of TiO₂ Assisted Photocatalytic Degradation of Nigrosine Dye

Abstract

This study examined the photocatalytic degradation of Nigrosine Dye (25 ppm) in aqueous solution using TiO₂ nanoparticles under sunlight irradiation. The optimal degradation efficiency of 70.23% was achieved at pH 6 after 4 hours of treatment. Comprehensive water quality analysis revealed significant alterations in parameters including alkalinity, turbidity, hardness, nitrate, calcium, magnesium, COD, BOD, sulfate, temperature and pH, with water hardness exceeding WHO drinking water standards. HPTLC analysis demonstrated successful dye degradation through reduced peak numbers in densitograms. Environmental risk assessment showed: 1) no antibacterial activity against E. coli at 10 ppm concentration; 2) improved seed germination rates (85% at pH 5.4 and 80% at pH 7) compared to untreated dye (10%), though slightly lower than control (96.25%). The results indicate TiO2 photocatalysis effectively degrades Nigrosine Dye but requires further optimization to address residual hardness and minor phytotoxicity observed at neutral pH conditions.