Zhou Jinjin, Wang Xinghao, Sun Zhaoyue, Gao Juan
University of Chinese Academy of Sciences, No.188, Tianquan Road, Nanjing, Jiangsu Province 211135, China; Institute of Soil Science, Chinese Academy of Sciences, No.298 Chuangyou Road, Nanjing, Jiangsu Province 211135, China.
Institute of Soil Science, Chinese Academy of Sciences, No.298 Chuangyou Road, Nanjing, Jiangsu Province 211135, China.
J Hazard Mater. 2025 Sep 5;495:138977. doi: 10.1016/j.jhazmat.2025.138977. Epub 2025 Jun 17.
Atrazine (ATZ) is a frequently detected herbicide in corn fields, and manganese oxides (MnO) are reactive soil components. Reportedly, the sole use of MnO cannot efficiently achieve ATZ removal in aqueous solution. However, this study found that 90.2 % of ATZ could be degraded on δ-MnO surfaces under dry conditions (mineral moisture content < 3 %, relative humidity (RH) ≤ 97.30 %). Atrazine-desisopropyl-2-hydroxy and 2-hydroxyatrazine were obtained as the main products through the dealkylation and hydrolysis of ATZ, and the intermediates exhibited low ecotoxicity toward aquatic organisms. The experiments were conducted at 23°C (RH: 6.40-97.3 %). Based on quenching experiments, Mn(IV) contributed approximately 88.0 % to ATZ degradation by accepting electrons from Cl and N in ATZ, forming Mn-Cl-C and Mn-N-H bonds, and reducing the activation energy required for hydrolysis based on DFT calculation. The oxygen vacancy in δ-MnO provided no considerable contribution to ATZ removal. RH notably influenced the processes, and the optimal RH value was 22.5 %. Similar mechanisms were observed for simazine, simetone, propazine, and ametryn on δ-MnO surfaces. In agricultural soil featuring low Mn contents, ATZ degradation was limited (< 1.0 %), however, the ATZ transformation efficiency increased to 31.2 % and 63.0 % after the addition of 1 % and 5 % δ-MnO particles. The effectiveness of δ-MnO was significantly correlated with the soil texture (R = 0.81-0.91, p < 0.05). These findings provide insights into the abiotic degradation mechanisms of triazine herbicides in dry soils, presenting strategies to remove triazine herbicide residues from soil.
阿特拉津（ATZ）是玉米田中经常检测到的一种除草剂，而锰氧化物（MnO）是土壤中的活性成分。据报道，单独使用MnO不能有效地去除水溶液中的ATZ。然而，本研究发现，在干燥条件下（矿物水分含量<3%，相对湿度（RH）≤97.30%），90.2%的ATZ可以在δ-MnO表面降解。通过ATZ的脱烷基化和水解反应，得到了去异丙基-2-羟基阿特拉津和2-羟基阿特拉津作为主要产物，这些中间体对水生生物的生态毒性较低。实验在23°C（RH：6.40-97.3%）下进行。基于猝灭实验，Mn(IV)通过接受ATZ中Cl和N的电子对ATZ降解的贡献约为88.0%，形成Mn-Cl-C和Mn-N-H键，并根据密度泛函理论计算降低了水解所需的活化能。δ-MnO中的氧空位对ATZ的去除没有显著贡献。RH对该过程有显著影响，最佳RH值为22.5%。在δ-MnO表面，西玛津、西草净、扑灭津和莠灭净也观察到了类似的机制。在锰含量较低的农业土壤中，ATZ的降解受到限制（<1.0%），然而，添加1%和5%的δ-MnO颗粒后，ATZ的转化效率分别提高到31.2%和63.0%。δ-MnO的有效性与土壤质地显著相关（R = 0.81-0.91，p<0.05）。这些发现为三嗪类除草剂在干燥土壤中的非生物降解机制提供了见解，提出了从土壤中去除三嗪类除草剂残留的策略。
