School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, China.
School of Chemical Engineering, Inner Mongolia Key Laboratory of Theoretical and Computational Chemistry Simulation, Inner Mongolia University of Technology, Hohhot, China.
Water Environ Res. 2023 Jun;95(6):e10898. doi: 10.1002/wer.10898.
TiO (P25) could significantly accelerate the degradation of carbon tetrachloride (CT) in the UV/K S O system by about 4 times, and 88.5% of the CT was dechlorinated. The presence of dissolved oxygen (DO) could delay the degradation process. The addition of P25 produced •O through the transformation of DO, so as to prevent the inhibitory effect. In this work, it was proved that P25 could not enhance the persulfate (PS) activation. The presence of P25 delayed the CT degradation in the absence of DO. Furthermore, the results of electron paramagnetic resonance (EPR) and quenching experiments demonstrated that the presence of P25 could produce •O , which could remove CT. Therefore, this work highlights the function of •O during the reaction and excludes the possibility that the presence of P25 could activate PS under the UV illumination. Then, the pathway of the CT degradation is discussed. Heterogeneous photocatalysis could provide a new method to deal with the problems caused by DO. PRACTITIONER POINTS: The main reason of the improvement in P25-PS-UV-EtOH system is transformation of dissolved oxygen into superoxide radical in presence of P25. The addition of P25 could not accelerate PS activation in P25-PS-UV-EtOH system. Photo-induced electron, superoxide radical, alcohol radical and •SO could all contribute to CT degradation, and the pathway is discussed.
TiO(P25)在 UV/K₂SO₄ 体系中能显著加速四氯化碳（CT）的降解，使其降解速率提高约 4 倍，约 88.5%的 CT 被脱氯。溶解氧（DO）的存在会延迟降解过程。P25 的添加会通过转化 DO 产生•O₂⁻，从而防止抑制作用。在这项工作中，证明了 P25 不能增强过硫酸盐（PS）的活化。在没有 DO 的情况下，P25 的存在会延迟 CT 的降解。此外，电子顺磁共振（EPR）和猝灭实验的结果表明，P25 的存在可以产生•O₂⁻，从而去除 CT。因此，这项工作强调了•O₂⁻在反应过程中的作用，并排除了 P25 在紫外光照射下可以激活 PS 的可能性。然后，讨论了 CT 降解的途径。多相光催化为解决 DO 引起的问题提供了一种新方法。
在 P25-PS-UV-EtOH 体系中，P25 的主要作用是将溶解氧转化为超氧自由基。在 P25-PS-UV-EtOH 体系中，P25 的添加不能加速 PS 的活化。光诱导电子、超氧自由基、醇自由基和•SO₄²⁻都可以促进 CT 的降解，并对降解途径进行了讨论。
