Solar-photocatalytic treatment of industrial wastewater using mechanically doped CNS-TiO2 and synergistic TiO2 incorporation: A promising cost-effective approach for industrial wastewater treatment

TiO2 alone demonstrated limited efficiency in degrading industrial wastewater. This study aims to the effectiveness of CNS-doped TiO2 nanoparticles for the degradation of anionic dyes, cationic dyes, and industrial wastewater. For the first time, mechanical milling is employed to synthesize CNS-doped TiO2 nanoparticles using thiourea as a precursor. This results in lattice strains and concomitant crystal and electronic structure changes. We note that these lead to increased photocatalytic activity. Mechanical milling creates a new phase known as brookite, which further improves photocatalytic efficiency through synergistic effects. The physicochemical properties and photocatalytic performance of CNS-TiO2 are evaluated and compared with mspd-TiO2 and commercially available Degussa P-25 TiO2. In photocatalytic degradation tests, remarkably, CNS-TiO2 exhibited beter degradation efficiency for anionic dyes (MO - 65 +/- 3 % in 120 min; CR - 100 % in 30 min), cationic dyes (MB - 100 % in 30 min; Rh B 100 % in 120 min) and industrial wastewater (similar to 100 % in 120 min). The treated wastewater TDS (56 +/- 2 ppm), TSS (0.16 g/L), CHNS, and COD (190 +/- 10 mg/L) results are closer to drinking water quality. The reusability test revealed lower activity in the mspd-TiO2 and CNS-TiO2 attributed to particle aggregation, the loss of activation sites, and mass loss. This study demonstrates CNS-TiO2 enhanced photocatalytic properties and cost-effectiveness making them highly promising for treating any industrial effluents containing dyes.