Fe/Co双金属材料活化过一硫酸盐氧化降解水中2,4-D

Oxidative degradation of 2,4-D in water by Fe/Co bimetallic nanocomposite-activated peroxymonosulfate

为了处理有机氯除草剂2,4-二氯苯氧乙酸(2,4-D)造成的环境污染,本研究采用液相还原法制备了铁钴双金属纳米颗粒(n-Fe/Co),并通过Fe、Co的合成比例优化了活化过一硫酸盐(PMS)体系对2,4-D的降解性能。结果表明:在pH为4.5的条件下,使用0.03 g·L^(-1)的n-Fe/Co和0.5 mmol·L^(-1)的PMS,2,4-D(10 mg·L^(-1))在30 min内完全去除,与单纯的纳米零价铁(nZVI)相比,2,4-D的去除率提升了60.9个百分点。n-Fe/Co可以在很宽的pH范围(2~9)和复杂的阴离子条件下有效去除2,4-D。自由基抑制实验表明羟基自由基是参与反应的主要活性物种(贡献率达到62.2%)。在中间产物分析的基础上,提出了2,4-D在n-Fe/Co-PMS体系中的降解机理和降解途径。研究表明,n-Fe/Co复合材料活化PMS系统在处理水中的2,4-D除草剂污染方面有很大的应用前景。

To alleviate environmental pollution caused by the organic chlorinated herbicide 2,4-dichlorophenoxyacetic acid(2,4-D),in this study,iron-cobalt bimetallic nanoparticles(n-Fe/Co)were prepared by liquid-phase reduction,and the degradation performance of 2,4-D via the activated peroxymonosulfate(PMS)system was optimized by adjusting the synthesis ratio of iron and cobalt.The results showed that 2,4-D(10 mg·L^(-1))was completely removed within 30 min using 0.03 g·L^(-1) of n-Fe/Co and 0.5 mmol·L^(-1) of PMS at pH 4.5,and the removal of 2,4-D was enhanced by 60.9 percent compared with the application of nano zero-valent iron(nZVI)alone.We found that n-Fe/Co could effectively remove 2,4-D over a wide pH range(2–9)and under complex anion conditions.Free radical inhibition experiments revealed that hydroxyl radicals were the main active species involved in the reaction,with a contribution rate of 62.2%.On the basis of our analysis of intermediate products,we propose a degradation mechanism and the degradation pathway of 2,4-D in the n-Fe/Co-PMS system.The findings of this study indicate that the n-Fe/Co nanocomposite-activated PMS system has considerable application potential for the treatment of 2,4-D herbicide pollution in water.