Laboratori d'Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.
J Phys Chem A. 2011 Feb 24;115(7):1234-42. doi: 10.1021/jp110753r. Epub 2011 Feb 2.
Solutions of about 0.25 mM of the β-blocker metoprolol tartrate (100 mg L(-1) total organic carbon) with 0.5 mM Fe(2+) in the presence and absence of 0.1 mM Cu(2+) of pH 3.0 have been comparatively degraded under electro-Fenton (EF) and photoelectro-Fenton (PEF) conditions. The electrolyses were carried out with two systems: (i) a single cell with a boron-doped diamond (BDD) anode and an air-diffusion cathode (ADE) for H(2)O(2) electrogeneration and (ii) a combined cell with a BDD/ADE pair coupled with a Pt/carbon felt (CF) cell. Overall mineralization was reached in all PEF treatments using both systems due to the efficient production of hydroxyl radical ((•)OH) from Fenton's reaction induced by UVA light and the quick photolysis of Fe(III) carboxylate complexes formed. In EF, the combined cell was much more potent than the single one by the larger (•)OH generation from the continuous Fe(2+) regeneration at the CF cathode, accelerating the oxidation of organics. However, almost total mineralization in EF was feasible using the combined cell in the presence of 0.1 mM Cu(2+), because of the parallel quick oxidation of Cu(II) carboxylate complexes by (•)OH. Metoprolol decay always followed a pseudo-first-order reaction. Aromatic products related to consecutive hydroxylation/oxidation reactions of metoprolol were detected by gas chromatography-mass spectrometry. The evolution of the aromatic 4-(2-methoxyethyl)phenol and generated carboxylic acids was followed by HPLC. The degradation rate and mineralization degree of metoprolol tartrate were limited by the removal of Fe(III) and Cu(II) complexes of ultimate carboxylic acids such as formic, oxalic, and oxamic. NH(4)(+) ion and to a lesser extent NO(3)(-) ion were released in all treatments, being quantified by ionic chromatography.
在 pH 3.0 条件下，存在和不存在 0.1 mM Cu(2+)的情况下，β受体阻滞剂酒石酸美托洛尔（100 mg L(-1)总有机碳）的约 0.25 mM 溶液与 0.5 mM Fe(2+)一起在电芬顿（EF）和光电芬顿（PEF）条件下进行比较降解。电解在两个系统中进行：（i）具有掺硼金刚石（BDD）阳极和空气扩散阴极（ADE）的单个电池，用于 H(2)O(2)电生成，以及（ii）具有 BDD/ADE 对的组合电池与 Pt/碳纤维毡（CF）电池耦合。由于 Fenton 反应诱导的 UVA 光产生的羟基自由基（(•)OH）和形成的 Fe(III) 羧酸络合物的快速光解，所有 PEF 处理均达到了总矿化。在 EF 中，组合电池比单电池更有效，因为 CF 阴极上连续的 Fe(2+)再生产生了更大的 (•)OH，从而加速了有机物的氧化。然而，在 EF 中，由于 (•)OH 对 Cu(II) 羧酸络合物的快速平行氧化，在存在 0.1 mM Cu(2+)的情况下，几乎可以实现完全矿化。美托洛尔的衰减总是遵循准一级反应。通过气相色谱-质谱法检测到与美托洛尔连续羟化/氧化反应相关的芳香产物。通过 HPLC 跟踪芳香 4-(2-甲氧基乙基)苯酚和生成的羧酸的演变。酒石酸美托洛尔的降解速率和矿化程度受最终羧酸如甲酸、草酸和草酰胺的 Fe(III) 和 Cu(II) 络合物的去除限制。在所有处理中都释放了 NH(4)(+)离子，并且在较小程度上释放了 NO(3)(-)离子，通过离子色谱法进行定量。
