Department of Chemical Engineering, McGill University, Quebec H3A 0C5, Canada.
Department of Chemical Engineering, McGill University, Quebec H3A 0C5, Canada.
Sci Total Environ. 2021 Sep 15;787:147645. doi: 10.1016/j.scitotenv.2021.147645. Epub 2021 May 8.
The widespread deterioration of our water systems requires new wastewater treatment technologies to ensure environmental protection. Conventional wastewater treatments were not designed for, and are therefore ineffective, at removing contaminants of emerging concern (CECs) such as pharmaceuticals, personal care products, pesticides, and industrial chemicals. Furthermore, treatment processes capable of breaking down CECs may produce toxic transformation products more harmful than the parent chemicals. Heterogeneous photocatalytic ozonation provides a promising option with high degradation and mineralization of organic compounds. The aim of the present paper is to review ecotoxicity reduction in water treated by heterogeneous photocatalytic ozonation as a measure of process viability. The discussion investigates changes in toxicity based on a variety of toxicity tests performed to evaluate potential effects on ecosystems, the types of catalysts and radiation sources used, the nature of the target contaminants, and the type of water matrix treated. Acute toxicity testing, TiO catalysts, and mercury-vapour lamps including blacklights were dominant in the reviewed studies, investigated in 86%, 84% and 79% of the papers, respectively. Pharmaceuticals were the main group of chemicals treated and the water matrices used were predominantly pure water and secondary effluent. Overall, the findings of these studies provide evidence that photocatalytic ozonation is an efficient process to remove persistent organic compounds while, most of the time, not increasing the toxicity of the effluent (as reported by 86% of the studies). Due to the wide variation in experimental set-ups, no clear correlation between reaction conditions and toxicity was determined, however, V. fischeri acute toxicity assays and chronic/sublethal tests appeared most sensitive to transformation products. Future studies need to a) incorporate multiple toxicity tests to produce a more reliable and inclusive ecotoxicity assessment of treated effluent and b) investigate immobilized catalysts and energy efficient radiation sources (i.e. solar and LEDs) for industrial applications.
我们的水系统广泛恶化，需要新的废水处理技术来确保环境保护。传统的废水处理技术并非专为去除新兴关注污染物（CECs）而设计，因此对于诸如药品、个人护理产品、农药和工业化学品等污染物无效。此外，能够分解 CECs 的处理工艺可能会产生比母体化学物质更具毒性的转化产物。多相光催化臭氧氧化提供了一种很有前途的选择，可实现有机化合物的高效降解和矿化。本文的目的是回顾多相光催化臭氧氧化处理水中的生态毒性降低情况，以此作为工艺可行性的衡量标准。讨论基于各种毒性测试来研究毒性变化，这些测试旨在评估对生态系统的潜在影响、使用的催化剂和辐射源的类型、目标污染物的性质以及处理的水基质类型。急性毒性测试、TiO2 催化剂和汞蒸气灯（包括黑光灯）在被综述的研究中占主导地位，分别占研究的 86%、84%和 79%。药品是主要的处理化学品组，使用的水基质主要是纯水和二级出水。总体而言，这些研究的结果表明，光催化臭氧氧化是一种有效去除持久性有机化合物的方法，而大多数情况下不会增加废水的毒性（86%的研究报告如此）。由于实验设置的差异很大，因此无法确定反应条件与毒性之间的明确相关性，但是发光细菌急性毒性试验和慢性/亚致死试验似乎对转化产物最敏感。未来的研究需要：a）结合多种毒性测试，以对处理后的废水进行更可靠和全面的生态毒性评估；b）研究固定化催化剂和节能辐射源（如太阳能和 LED），以用于工业应用。
