Mehralipour Jamal, Kermani Majid
Research Center of Environmental Health Technology, Iran University of Medical Sciences, Tehran, Iran.
Student Research Committee, Iran University of Medical Sciences, Tehran, Iran.
J Environ Health Sci Eng. 2021 Mar 29;19(1):625-639. doi: 10.1007/s40201-021-00633-w. eCollection 2021 Jun.
In this research work, we investigated the ability of the oxidative degradation of 2, 4-Dichlorophenoxy acetic acid herbicide via ultrasonic-assisted in electro-activation of the persulfate system in the presence of nano-zero valent iron. The effect of experimental parameters such as pH value [4-8], electrical current (0.5-1 A), persulfate concentration (0.25-0.5 mg.l), nano zero-valent iron dose (0.05-0.1 mg.l), and initial organic pollutant concentration (50-100 mg.l) on the ultrasonic-electropersulfate process performance was assessed via central composite design. The combination of ultrasonic waves with the electrochemical process to activation of persulfate showed better efficiency into 2, 4-Dichlorophenoxy acetic acid herbicide degradation compared to their implementation in individual and binary systems. Following optimal conditions (pH = 5.62, 0.80 A applied electrical current, 0.39 mg/L persulfate concentration, 0.07 mg/L nano-zero valent iron, and 50 mg/L 2,4-Dichlorophenoxy acetic acid concentration in 40 min reaction), nearly 91% removal was done. Moreover, the complete removal of 2, 4-Dichlorophenoxy acetic acid, 92% COD, and 88% TOC removal was achieved by this process near 140 min reaction. The scavenging experiment confirmed the role of free oxidizing species in the degradation of 2, 4-Dichlorophenoxy acetic acid during the process. Approximately 50% improved 2, 4-Dichlorophenoxy acetic acid removal in the process against the inclusive efficiency of single mechanisms. The obtained results were fitted to the pseudo-first-order kinetic model with a high correlation coefficient (R = 0.96). Five important intermediate products of 2, 4-D oxidation were 2, 4-dichlorophenol (2, 4-DCP), 2, 6-dichlorophenol (2, 6-DCP), 4, 6 dichlororesorcinol (4, 6-DCR), 2-chlorohydroquinone (2-CHQ), and 2-chloro-1, 4-benzoquinone (2-CBQ). In the end, can be employed as a satisfactory advanced oxidation process in high mineralization of 2, 4-D and refractory organic pollutants.
在本研究工作中，我们研究了在纳米零价铁存在下，通过超声辅助电活化过硫酸盐体系对2,4-二氯苯氧乙酸除草剂进行氧化降解的能力。通过中心复合设计评估了pH值[4-8]、电流(0.5-1 A)、过硫酸盐浓度(0.25-0.5 mg/L)、纳米零价铁剂量(0.05-0.1 mg/L)和初始有机污染物浓度(50-100 mg/L)等实验参数对超声-电过硫酸盐工艺性能的影响。与单独体系和二元体系相比，超声波与电化学过程结合活化过硫酸盐对2,4-二氯苯氧乙酸除草剂的降解表现出更高的效率。在最佳条件下（pH = 5.62，施加电流0.80 A，过硫酸盐浓度0.39 mg/L，纳米零价铁0.07 mg/L，反应40分钟时2,4-二氯苯氧乙酸浓度50 mg/L），去除率接近91%。此外，在反应近140分钟时，该工艺实现了2,4-二氯苯氧乙酸的完全去除、92%的化学需氧量（COD）去除率和88%的总有机碳（TOC）去除率。清除实验证实了自由基氧化物种在该过程中对2,4-二氯苯氧乙酸降解的作用。与单一机制的综合效率相比，该过程中2,4-二氯苯氧乙酸的去除率提高了约50%。所得结果与伪一级动力学模型拟合，相关系数较高（R = 0.96）。2,4-二氯苯氧乙酸氧化的五个重要中间产物为2,4-二氯苯酚（2,4-DCP）、2,6-二氯苯酚（2,6-DCP）、4,6-二氯间苯二酚（4,6-DCR）、2-氯对苯二酚（2-CHQ）和2-氯-1,4-苯醌（2-CBQ）。最后，该工艺可作为一种令人满意的高级氧化工艺用于2,4-二氯苯氧乙酸和难降解有机污染物的高效矿化。
