Efficient heterogeneous electro -Fenton incineration of a contaminant of emergent concern-cotinine- in aqueous medium using the magnetic double perovskite oxide Sr2FeCuO6 as a highly stable catalayst: Degradation kinetics and oxidation products
Efficient heterogeneous electro -Fenton incineration of a contaminant of emergent concern-cotinine- in aqueous medium using the magnetic double perovskite oxide Sr2FeCuO6 as a highly stable catalayst: Degradation kinetics and oxidation products
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DOI：
10.1016/j.apcatb.2018.09.002
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
S. Hammouda;Claudio Salazar;Feiping Zhao;D. Ramasamy;Evgenia Laklova;S. Iftekhar;I. Babu;M. Sillanpää
中科院分区：
文献类型：
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作者：
S. Hammouda;Claudio Salazar;Feiping Zhao;D. Ramasamy;Evgenia Laklova;S. Iftekhar;I. Babu;M. Sillanpää
可替宁是尼古丁的主要代谢物，最近在环境中被检测到，并被认为是水中的新污染物。它的化学处理在文献中很少被研究。首次将双钙钛矿型氧化物作为多相催化剂应用于电化学高级氧化，并选择可替宁作为目标污染物。为此，合成了高稳定磁性双钙钛矿结构的Sr2FeCuO6。以磁性双钙钛矿Sr2FeCuO6为多相催化剂，比较了在pH 3.0的人工合成硫酸盐溶液中，有(AO-H_2O_2-BDD)阳极氧化和无电生成过氧化氢(AO-BDD)阳极氧化以及非均相电芬顿(EF)法的可替宁矿化。采用含硼金刚石和碳毡阴极的500 m L搅拌反应器进行了对比电解实验。由于Fenton-S反应产生的羟基自由基氧化了铁中心和阴极上产生的过氧化氢，电芬顿过程中观察到了更快的矿化衰退。此外，还指出了铜离子中心之间的协同作用。浸取实验证实了催化剂的高稳定性和非均相作用。考察了电流强度和可替宁浓度的影响。共检测到7种稳定的有机中间体，其中4种分别鉴定为N-羟甲基去甲肾上腺素、去甲肾上腺素、4-氧代-4-(3-吡啶基)丁酸和4-(3-吡啶基)-3-丁烯酸。初始氮以硝酸盐形式释放，少量以铵离子形式释放。检测到短链脂肪酸，主要是草酸和甲酸。EPR分析表明，可替宁主要是通过自由基dotOH的攻击而分解的。最后提出了包括所有检测产物的可替宁矿化反应序列。磁性催化剂至少可重复使用3次，突出了设想的非均相工艺的实际适用性。
Cotinine, the majormetabolite of nicotine, has been recently detected in the environment and considered as emerging contaminant in waters. Its chemical treatment has scarcely been investigated in the literature. Here, we show for the first time that double perovskite oxide can be used as heterogeneous catalyst for electrochemical advanced oxidation application and cotinine was selected as the target pollutant. Highly stable magnetic double perovskite Sr2FeCuO6was synthetized for this purpose. The cotinine mineralization in a synthetic sulfate solution of pH 3.0 has been comparatively assessed by anodic oxidation with (AO-H2O2-BDD) and without electro-generated hydrogen peroxide (AO-BDD) and by the heterogeneous electro-Fenton (EF) processes using the magnetic double perovskite Sr2FeCuO6as the heterogeneous catalyst. The comparative electrolysis experiments were carried out with 500 mL stirred reactor equipped with a boron-doped diamond (BDD) and a carbon felt cathode. Faster mineralization decay was observed with the electro Fenton process due to the additional oxidation by hydroxyl radicals produced from Fenton´s reaction between the iron sites and the electro-generated hydrogen peroxide at the cathode. Moreover, the synergistic effect of the cuprous sites was pointed out. The leaching test confirms the high stability of the catalyst and its heterogeneous action. The influence of current intensity and cotinine concentration was examined. Seven stable organics intermediates were detected and four of them were identified asN-Hydroxymethyl norcotinine, norcotinine, 4-oxo-4-(3-pyridyl) butanoic acid and 4-(3-Pyridyl)-3-butenoic Acid. The initial N was released as nitrate and, in smaller proportion, as ammonium ion. Short chain aliphatic acids, mainly oxalic and formic acids were detected. EPR analyses revealed that cotinine was mainly decomposed by the attack ofradical dotOH. A reaction sequence for cotinine mineralization involving all the detected products is finally proposed. The reusability of the magnetic catalyst for at least 3 times highlights the practical applicability of the envisaged heterogeneous process.