School of Civil Engineering & Transportation, South China University of Technology, Guangzhou, 510640, PR China; SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, School of Environment, South China Normal University, Guangzhou, 510006, PR China.
School of Civil Engineering & Transportation, South China University of Technology, Guangzhou, 510640, PR China.
Water Res. 2020 Sep 1;182:115975. doi: 10.1016/j.watres.2020.115975. Epub 2020 May 27.
Neonicotinoids (NEOs), as the most widely used pesticides, pose a serious threat to water ecosystems, especially clothianidin (CLO). However, the degradation behavior of CLO, as a new type of persistent organic pollutant, is rarely studied in wastewater treatment. To bridge this gap, heterogeneous electro-Fenton system using three-dimension electrodes made of biochar-supported zero-valent iron nanoparticle hybrid material (NZVI-BC), abbreviated as 3D-ICE-EF system, is invented and initially applied in CLO wastewater degradation, without the addition of Fenton reagent. NZVI-BC in 3D-ICE-EF system can concentrate CLO on electrodes by excellent adsorption and effectively eliminate it to achieve self-cleaning effect. In addition, the deposition of iron mud (Fe(OH)) and the circular utilization of Fe in Fenton system is effectively improved by the addition of hydroquinone (HQ) in 3D-ICE-EF system. The pH applicable scope of Fenton system is extended to alkaline condition by the applications of NZVI-BC electrodes. The increase in the acidity of electrolyte is considered the primary reason of the high degradation efficiency of CLO in 3D-ICE-EF system at an initial pH of 9.0. The degradation performance of 3D-ICE-EF system tends to be promoted by the increase of current intensity and air flow rate. Seven plausible mechanisms of CLO degradation were identified in 3D-ICE-EF system. The ecotoxicity evaluation of degradation products indicated that CLO degradation in 3D-ICE-EF system exhibits a remarkable tendency to reduce toxicity levels.
新烟碱类（NEOs）作为使用最广泛的农药，对水生态系统构成了严重威胁，尤其是噻虫嗪（CLO）。然而，作为一种新型持久性有机污染物，CLO 在废水处理中的降解行为很少被研究。为了弥补这一空白，发明了一种使用生物炭负载零价铁纳米粒子杂化材料（NZVI-BC）的三维电极的非均相电-Fenton 系统（简称 3D-ICE-EF 系统），并初步应用于 CLO 废水降解，无需添加 Fenton 试剂。3D-ICE-EF 系统中的 NZVI-BC 通过优异的吸附作用将 CLO 浓缩在电极上，并有效地将其去除，从而实现自清洁效应。此外，通过在 3D-ICE-EF 系统中添加对苯二酚（HQ），有效提高了 Fenton 系统中铁泥（Fe(OH)）的沉积和铁的循环利用。NZVI-BC 电极的应用将 Fenton 系统的 pH 适用范围扩展到碱性条件。考虑到初始 pH 值为 9.0 时 3D-ICE-EF 系统中 CLO 高降解效率的主要原因是电解质酸度增加。通过增加电流强度和空气流量，3D-ICE-EF 系统的降解性能趋于得到提升。在 3D-ICE-EF 系统中鉴定了 CLO 降解的七种可能机制。降解产物的生态毒性评价表明，3D-ICE-EF 系统中 CLO 的降解表现出显著降低毒性水平的趋势。
