Department of Chemistry and Biochemistry, North Carolina Central University, Durham, North Carolina.
Department of Environmental, Earth and Geospatial Sciences, North Carolina Central University, Durham, North Carolina.
Water Environ Res. 2019 Mar;91(3):198-207. doi: 10.1002/wer.1018. Epub 2019 Feb 1.
Herein, we report the comparison of two different mixing methods for reductive dechlorination of gamma-hexachlorocyclohexane (γ-HCH), aldrin, and p, p'-dichlorodiphenyl-trichloroethane (p, p'-DDT), using iron/palladium (Fe/Pd) bimetallic nanoparticles. A noticeable enhancement of the reaction rate was found when the reductive dechlorination reaction was carried out in an ultrasound bath as compared with a platform shaker. These enhancements could be attributed to (a) the continuous cleaning and chemical activation of the surfaces of nanoscale Fe/Pd bimetallic nanoparticles by the combined chemical and physical effects of acoustic cavitation; and (b) the accelerated mass transport rates of target POPs to the surfaces of the Fe/Pd nanoparticles. Finally, the degradation intermediates and final products were determined by gas chromatography/mass spectrometry (GC/MS) analysis and the plausible degradation pathways for γ-HCH, aldrin, and p, p'-DDT by Fe/Pd bimetallic nanoparticles were proposed. PRACTITIONER POINTS: Exposure to POPs is a resilient global environmental and health issue. Fe/Pd bimetallic nanoparticles demonstrated > 90 % removal of POPs in the first 30 minutes of the reaction via ultrasonic mixing. GC-MS analyses provided verification of POPs degradation intermediates and final products.
本文报告了两种不同的混合方法在还原脱氯γ-六氯环己烷（γ-HCH）、艾氏剂和 p,p'-二氯二苯三氯乙烷（p,p'-DDT）方面的比较，使用铁/钯（Fe/Pd）双金属纳米粒子。与平台振荡器相比，当还原脱氯反应在超声浴中进行时，反应速率明显提高。这些增强作用可能归因于（a）声空化的化学和物理综合效应连续清洁和化学活化纳米级 Fe/Pd 双金属纳米粒子的表面；（b）目标持久性有机污染物向 Fe/Pd 纳米粒子表面的传质速率加快。最后，通过气相色谱/质谱（GC/MS）分析确定了降解中间体和最终产物，并提出了 Fe/Pd 双金属纳米粒子对 γ-HCH、艾氏剂和 p,p'-DDT 的可能降解途径。
持久性有机污染物的暴露是一个持久存在的全球性环境和健康问题。通过超声混合，Fe/Pd 双金属纳米粒子在反应的前 30 分钟内实现了超过 90%的持久性有机污染物去除率。GC-MS 分析验证了持久性有机污染物降解中间体和最终产物。
