Electrochemical degradation of the herbicide picloram using a filter-press flow reactor with a boron-doped diamond or β-PbO2 anode
Electrochemical degradation of the herbicide picloram using a filter-press flow reactor with a boron-doped diamond or β-PbO2 anode
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DOI：
10.1016/j.electacta.2015.05.134
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发表时间：
2015-10
影响因子：
6.6
通讯作者：
Gabriel F. Pereira;R. Rocha‐Filho;N. Bocchi;S. Biaggio
中科院分区：
文献类型：
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作者：
Gabriel F. Pereira;R. Rocha‐Filho;N. Bocchi;S. Biaggio
在压滤反应器中进行恒电流电解，以研究使用掺硼金刚石 (BDD) 或 β-PbO2 阳极毒莠定（100 mg L−1，来自商业除草剂配方）的电化学降解。研究了 pH（3、6 或 10）、施加电流密度（japl= 10、30 或 50 mA cm−2）以及支持电解质（0.10 M Na2SO4 水溶液）中是否存在 Cl 离子 (25 mM) 的影响，同时监测毒莠定浓度、溶液化学需氧量 (COD) 和总有机碳含量 (TOC) 以及能耗作为电解的函数时间。从获得的结果来看，很明显，使用任一阳极都可以电化学降解毒莠定，但总体性能不同。一般来说，支持电解质中Cl离子的存在（导致产生活性氯）对两种阳极的性能都有积极的影响，除了使用BDD阳极的TOC消减；当 HClO 是主要活性氯时，pH 值约为 6 时可获得最佳电降解性能。随着 japl 的增加，毒莠定和溶液 TO 的初始电降解速度加快，但是，正如预期的那样，在 japl 的最低值时总是获得较低的能量消耗。在毒莠定的初始降解过程中，两种阳极的性能几乎相同；然而，BDD阳极在溶液COD或TOC的消除方面大大超过了β-PbO2阳极。这证实了阳极氧化能力的重要性，即使当活性氯的间接氧化同时发挥作用时也是如此。
Galvanostatic electrolyses are performed in a filter-press reactor to investigate the electrochemical degradation of picloram (100 mg L−1, from a commercial herbicide formulation) using a boron-doped diamond (BDD) or β-PbO2anode. The effect of pH (3, 6, or 10), applied current density (japl= 10, 30, or 50 mA cm−2), and absence or presence of Cl–ions (25 mM) in the supporting electrolyte (aqueous 0.10 M Na2SO4) is investigated, while the picloram concentration, solution chemical oxygen demand (COD) and total organic carbon content (TOC), and energy consumption are monitored as a function of electrolysis time. From the obtained results, it is clear that the electrochemical degradation of picloram is possible using either of the anodes, but with different overall performances. In general, the presence of Cl–ions in the supporting electrolyte (leading to electrogenerated active chlorine) has a positive effect on the performance of both anodes, except forTOCabatement using the BDD anode; the best electrodegradation performances are attained at pH values around 6, when HClO is the predominant active-chlorine species. Faster rates of initial electrodegradation of picloram and of solutionTOCabatement are obtained asjaplis increased, but, as expected, lower energy consumptions are always attained at the lowest value ofjapl. The performances of the two anodes are virtually the same in the initial degradation of picloram; however, the BDD anode greatly surpasses the β-PbO2anode in the abatement of solutionCODorTOC. This confirms the importance of the oxidation power of the anode, even when indirect oxidation by active chlorine plays a concomitant role.