Zhou Yao, Wang Liangjie, Qian Feng, Kong Linghao, Wu Yang, Xie Xiaolin, Song Yonghui
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China; College of Environment Science, Liaoning University, Shenyang 110136, PR China.
The Key Laboratory of Water and Sediment Sciences (Ministry of Education), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, PR China.
Water Res. 2025 Sep 1;283:123848. doi: 10.1016/j.watres.2025.123848. Epub 2025 May 16.
Malathion is a widely used insecticide with toxic effects on humans and is considered to be genotoxic and carcinogenic. As the common free radicals in advanced oxidation processes, hydroxyl radical (•OH) and sulfate radical (SO) can efficiently degrade malathion, but highly toxic product malaoxon is prone to produce in this process. In response to this issue, polyethyleneterephthalate (PET) plastics and KFeO were utilized to prepare Fe-doped porous plastic-derived carbon material (FAC) as peroxymonosulfate (PMS) trigger to perform low toxicity degradation of malathion. FAC (100 mg/L) could trigger 0.5 mM PMS to completely degrade 10 mg/L malathion within 15 min. PMS alone, singlet oxygen (O), •OH, and SO contributed to the degradation of malathion, in which O played the most important role with a contribution of 53.5%. Density functional theory (DFT) was employed to elucidate the reaction site of O for malathion, further illustrating O with the product of desmethyl malathion. Based on the DFT program, we calculated the theoretical second-order rate constants, the reactivity of O with malathion to produce desmethyl malathion, was 1.88 × 10 M s, which was much higher than another reaction pathway with the highly toxic product of malaoxon (1.36 × 10 M s). The binding energies of various key proteins of zebrafish and human beings to the degradation products were analyzed by molecular dynamics to characterize their ecological and human toxicity. Surprisingly, in contrast to the highly toxic intermediate malaoxon in the previous studies, desmethyl malathion, the main degradation product in FAC/PMS system, has a significantly low toxicity.
马拉硫磷是一种广泛使用的杀虫剂，对人类具有毒性作用，被认为具有遗传毒性和致癌性。作为高级氧化过程中常见的自由基，羟基自由基（•OH）和硫酸根自由基（SO）能够有效降解马拉硫磷，但在此过程中容易产生高毒性产物马拉氧磷。针对这一问题，利用聚对苯二甲酸乙二酯（PET）塑料和高铁酸钾制备了铁掺杂多孔塑料衍生碳材料（FAC）作为过一硫酸盐（PMS）的引发剂，以实现对马拉硫磷的低毒性降解。FAC（100 mg/L）能够引发0.5 mM的PMS在15分钟内完全降解10 mg/L的马拉硫磷。单独的PMS、单线态氧（O）、•OH和SO对马拉硫磷的降解都有贡献，其中O发挥的作用最为重要，贡献率为53.5%。采用密度泛函理论（DFT）阐明O与马拉硫磷的反应位点，并进一步说明O与去甲基马拉硫磷产物的关系。基于DFT程序，我们计算了理论二级速率常数，O与马拉硫磷反应生成去甲基马拉硫磷的反应性为1.88×10 M s，远高于生成高毒性产物马拉氧磷的另一条反应途径（1.36×10 M s）。通过分子动力学分析了斑马鱼和人类各种关键蛋白质与降解产物的结合能，以表征它们的生态毒性和人体毒性。令人惊讶的是，与先前研究中高毒性的中间体马拉氧磷不同，FAC/PMS体系中的主要降解产物去甲基马拉硫磷的毒性显著较低。
