John Deepthi, Jose Jiya, Bhat Sarita G, Achari V Sivanandan
School of Environmental Studies, Cochin University of Science and Technology, Kochi, 682022, Kerala, India.
Department of Chemistry, Deva Matha College, Kuravilangad, 686633, Kerala, India.
Heliyon. 2021 Jul 3;7(7):e07451. doi: 10.1016/j.heliyon.2021.e07451. eCollection 2021 Jul.
Advanced oxidation processes (AOPs) which involve the generation of highly reactive free radicals have been considered as a promising technology for the decontamination of water from chemical and bacterial pollutants. In this study, integration of two major AOPs ., heterogeneous photocatalysis involving TiO-reduced graphene oxide (T-RGO) nanocomposite and activated persulfate (PS) based oxidation was attempted to remove diclofenac (DCF), a frequently detected pharmaceutical contaminant in water. The enhanced visible light responsiveness of T-RGO would facilitate the use of direct sunlight as a benign and cost effective source of energy for the photocatalytic activation. By combining PS based oxidation process with T-RGO mediated photocatalysis, a DCF removal efficiency of more than 98% was achieved within 30 min. The effect of operating parameters like PS concentration and pH on DCF removal was assessed. Radical scavenging experiments indicated that apart from radical oxidation involving OH and radicals, a non-radical oxidation pathway was also taking place in the degradation. The antibacterial properties of the integrated system were also evaluated using and as representative bacteria. The presence of PS in the photocatalytic reaction system improved the antibacterial activity of the composite against the two strains studied. Cytotoxicity of T-RGO nanocomposite was assessed using human macrophage cell lines and the results showed that the composite is biocompatible and nontoxic at the recommended dosage for water treatment in the present study.
涉及高活性自由基生成的高级氧化过程（AOPs）被认为是一种很有前景的技术，可用于去除水中的化学和细菌污染物。在本研究中，尝试将两种主要的AOPs——涉及TiO-还原氧化石墨烯（T-RGO）纳米复合材料的多相光催化和基于过硫酸盐（PS）的活化氧化相结合，以去除双氯芬酸（DCF），一种在水中经常检测到的药物污染物。T-RGO增强的可见光响应性将有助于将阳光作为一种良性且具有成本效益的能源用于光催化活化。通过将基于PS的氧化过程与T-RGO介导的光催化相结合，在30分钟内实现了超过98%的DCF去除效率。评估了PS浓度和pH等操作参数对DCF去除的影响。自由基清除实验表明，除了涉及·OH和·自由基的自由基氧化外，降解过程中还发生了非自由基氧化途径。还使用[具体细菌1]和[具体细菌2]作为代表性细菌评估了集成系统的抗菌性能。光催化反应体系中PS的存在提高了复合材料对所研究的两种菌株的抗菌活性。使用人巨噬细胞系评估了T-RGO纳米复合材料的细胞毒性，结果表明，在本研究中推荐的水处理剂量下，该复合材料具有生物相容性且无毒。
