Xia Alin, Yu Haitao, Tan Longyuan, Yang Laxiang
College of Food and Chemical Engineering, Shaoyang University, No. 28, Lane 3, Shaoshui West Road, Shaoyang, Hunan 422000, China.
College of Food and Chemical Engineering, Shaoyang University, No. 28, Lane 3, Shaoshui West Road, Shaoyang, Hunan 422000, China.
Ultrason Sonochem. 2025 Aug;119:107411. doi: 10.1016/j.ultsonch.2025.107411. Epub 2025 May 30.
Persistent pesticides pose significant environmental and health risks due to their strong resistance to conventional degradation methods. This study investigates the degradation of lindane (LND), a perchlorinated pesticide, using a sulfite-assisted ultrasonic (SF/US) process, focusing on the critical role of aqueous electrons (e) in reductive dechlorination. Aqueous electrons were indirectly identified as the primary reactive species in the SF/US system for pollutant degradation, providing insights into US-induced reduction mechanisms. The SF/US system significantly enhanced LND removal, achieving 99.4 % ± 1.0 % degradation within 100 min, compared to 88.9 % ± 1.5 % under ultrasound alone. Kinetic analysis showed that sulfite addition nearly doubled the reaction rate constant (from 0.022 to 0.041 min), confirming that e drive LND degradation more efficiently than hydroxyl radicals (HO). Scavenging experiments further demonstrated that nitrate strongly inhibited degradation, while tert-butanol (TBA) had minimal effect, verifying that e, rather than HO, dominate the process. The efficiency of SF/US was influenced by various factors, with optimal removal achieved at 200 kHz, oxygen-depleted conditions, and pH 10. The degradation pathway primarily involved sequential reductive dechlorination of LND, progressing through pentachlorocyclohexene, tetrachlorocyclohexadiene, and trichlorobenzene intermediates before ultimately forming non-toxic aromatic derivatives such as hydroquinone and phenol. These findings highlight SF/US as a novel and highly efficient strategy for the remediation of chlorinated pesticides in water treatment.
持久性农药由于对传统降解方法具有很强的抗性，因而对环境和健康构成重大风险。本研究采用亚硫酸盐辅助超声（SF/US）工艺研究了一种全氯代农药林丹（LND）的降解情况，重点关注水合电子（e）在还原脱氯中的关键作用。水合电子被间接确定为SF/US系统中污染物降解的主要活性物种，这为超声诱导的还原机制提供了见解。SF/US系统显著提高了LND的去除率，在100分钟内实现了99.4%±1.0%的降解，而仅超声处理时的降解率为88.9%±1.5%。动力学分析表明，添加亚硫酸盐使反应速率常数几乎增加了一倍（从0.022增至0.041 min），证实了e比羟基自由基（HO）更有效地驱动LND降解。清除实验进一步表明，硝酸盐强烈抑制降解，而叔丁醇（TBA）的影响最小，这验证了主导该过程的是e而非HO。SF/US的效率受多种因素影响，在200 kHz、贫氧条件和pH值为10时实现了最佳去除效果。降解途径主要涉及LND的顺序还原脱氯，依次经过五氯环己烯、四氯环己二烯和三氯苯中间体，最终形成对苯二酚和苯酚等无毒芳香衍生物。这些发现突出了SF/US作为一种用于水处理中氯代农药修复的新型高效策略。
