MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China.
Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia 4072, QLD, Australia.
Environ Sci Technol. 2023 Nov 28;57(47):18452-18461. doi: 10.1021/acs.est.2c06327. Epub 2023 Jan 20.
Ultraviolet (UV)/chlor(am)ine processes are emerging advanced oxidation processes (AOPs) for water decontamination and raising continuous attention. However, limitations appear in the UV/hypochlorite and UV/monochloramine for removing specific contaminants ascribed to the differences in the sorts and yields of free radicals. Here, this study reports UV/dichloroisocyanurate (NaDCC) as a novel source of radicals. NaDCC was demonstrated to be a well-balanced compound between hypochlorite and monochloramine, and it had significant UV absorption and a medium intrinsic quantum yield. The UV/NaDCC produced more substantial hydroxyl radicals (·OH) and reactive chlorine species (RCSs, including Cl·, ClO·, and Cl·) than conventional UV/chlor(am)ine, thereby generating a higher oxidation efficiency. The reaction mechanisms, environmental applicability, and energy requirements of the UV/NaDCC process for emerging contaminants (ECs) abatement were further investigated. The results showed that ·OH and ·NH attacked ECs mostly through hydrogen atom transfer (HAT) and radical adduct formation, whereas Cl· destroyed ECs mainly through HAT and single electron transfer, with ClO· playing a certain role through HAT. Kinetic model analyses revealed that the UV/NaDCC outperformed the conventional UV/chlor(am)ine in a variety of water matrices with superior degradation efficiency, significantly saving up to 96% electrical energy per order. Overall, this study first demonstrates application prospects of a novel AOP using UV/NaDCC, which can compensate for the deficiency of the conventional UV/chlor(am)ine AOPs.
紫外线（UV）/氯（胺）工艺是一种新兴的高级氧化工艺（AOPs），可用于水净化，并引起了持续关注。然而，在 UV/次氯酸盐和 UV/单氯胺去除特定污染物方面存在局限性，这归因于自由基种类和产率的差异。本研究报告称，二氯异氰尿酸钠（NaDCC）是一种新型的自由基源。NaDCC 被证明是介于次氯酸盐和单氯胺之间的平衡化合物，具有显著的紫外线吸收和中等的固有量子产率。与传统的 UV/氯（胺）相比，UV/NaDCC 产生了更多的羟基自由基（·OH）和活性氯物种（RCSs，包括 Cl·、ClO·和 Cl·），从而产生了更高的氧化效率。进一步研究了 UV/NaDCC 工艺对新兴污染物（ECs）去除的反应机制、环境适用性和能源需求。结果表明，·OH 和·NH 主要通过氢原子转移（HAT）和自由基加合物形成攻击 ECs，而 Cl·主要通过 HAT 和单电子转移破坏 ECs，ClO·通过 HAT 发挥一定作用。动力学模型分析表明，在多种水基质中，UV/NaDCC 的性能优于传统的 UV/氯（胺），每级可节省高达 96%的电能。总的来说，本研究首次证明了使用 UV/NaDCC 的新型 AOP 的应用前景，可弥补传统的 UV/氯（胺）AOP 的不足。
