Photocatalytic performance of N-doped TiO nano-catalyst for phenolic compounds removal from industrial wastewaters.

This study is focused on the synthesis and evaluation of TiO and N-doped TiO for the photocatalytic degradation of phenol as a noxious substance commonly present in the industrial process effluents with harmful effects on human and the environment. The research addresses the critical environmental challenge posed by phenol-contaminated effluents from petrochemical industries. Leveraging Response Surface Methodology with Box-Behnken design, 17 experiments were conducted to analyze the impact of independent variables such as photo-catalyst dosage, pH, and irradiation time on degradation efficiency. Notably, the average crystallite sizes were determined as 20 nm for TiO and 58.3 nm for N-doped TiO. Energy bandgap assessments show enhanced performance in N-TiO compared to TiO under sunlight. Energy bandgaps of N-TiO and TiO were obtained as 2.45 and 2.75 eV, respectively. The study emphasizes the impact of initial pH on the photocatalytic degradation process, highlighting the superior performance of N-TiO under neutral conditions. The interfacial charge alteration of N-TiO based on pH plays a pivotal role in dispersion and adsorption dynamics, influencing the photocatalytic removal efficiency significantly. In this study, a significant improvement in photocatalytic degradation of an industrial wastewater containing phenolic compounds, with maximum efficiencies of 99.87%, 99.78% and 99.779 under UV, visible and sunlight was observed, respectively. The optimal conditions for phenol degradation were pH = 7, 1 g/L of catalyst, and irradiation time = 30 min under low intensity UV (18 W), visible light (18 W) and sunlight, resulting in 99.823% phenol degradation. The synthesized N-doped TiO showed excellent stability and recyclability for the treatment of phenolic wastewaters. This research not only advances the understanding of TiO-based photo-catalysts but also provides a practical, efficient solution for treating phenol-contaminated industrial wastewaters. The findings of this study have significant implications for environmental remediation in the petrochemical sector.