Laboratori d'Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.
Laboratori d'Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.
Water Res. 2015 Sep 15;81:178-87. doi: 10.1016/j.watres.2015.05.057. Epub 2015 May 29.
The degradation of 130 mL of mixtures of food azo dyes E122, E124 and E129 has been studied by electro-Fenton (EF) and UVA photoelectro-Fenton (PEF) using a stirred tank reactor with either a boron-doped diamond (BDD) or Pt anode and an air-diffusion cathode. The main oxidant was hydroxyl radical formed at the anode from water oxidation and in the bulk from Fenton's reaction between added Fe(2+) and H2O2 generated at the cathode. In sulfate medium, fast decolorization was found for all systems, but the almost total mineralization was more rapidly achieved by PEF with BDD. The performance with a real water matrix was slightly worse, although the removal of total organic load was still as high as 95%. The solar PEF (i.e., SPEF) treatment of dye mixtures using a 2.5 L flow plant with a BDD/air-diffusion cell coupled to a planar solar photoreactor is also reported. Fast decolorization and almost total mineralization was found in the presence of either sulfate, perchlorate, nitrate or a mixture of sulfate + chloride ions. In chloride medium, however, the formation of recalcitrant chloroderivatives decelerated the degradation process. Greater current efficiency and lower specific energy consumption were attained in sulfate medium at lower current density and higher azo dye content. A plausible reaction sequence based on 18 aromatic intermediates identified by GC-MS and 6 short-linear carboxylic acids detected by ion-exclusion HPLC has been proposed. The SPEF process promoted the photodegradation of Fe(III)-oxalate complexes and other undetected products. Sulfate and nitrate ions were always released to the medium.
已使用带有掺硼金刚石（BDD）或 Pt 阳极和空气扩散阴极的搅拌槽反应器，通过电芬顿（EF）和 UVA 光电芬顿（PEF）研究了食品偶氮染料 E122、E124 和 E129 的混合物 130ml 的降解情况。主要氧化剂是由阳极上水氧化产生的羟基自由基和在本体中由阴极生成的添加的 Fe(2+)和 H2O2 之间的芬顿反应产生的。在硫酸盐介质中，所有体系都发现快速脱色，但 PEF 与 BDD 几乎完全矿化得更快。尽管总有机负荷的去除率仍高达 95%，但实际水基质的性能略有下降。还报道了使用带有 BDD/空气扩散电池的 2.5L 流量装置和平面太阳能光反应器耦合的太阳能 PEF（即 SPEF）处理染料混合物。在存在硫酸盐、高氯酸盐、硝酸盐或硫酸盐+氯化物混合物的情况下，发现快速脱色和几乎完全矿化。然而，在氯化物介质中，难降解的氯衍生物的形成会使降解过程减速。在较低电流密度和较高偶氮染料含量下，在硫酸盐介质中可以实现更高的电流效率和更低的比能耗。根据 GC-MS 鉴定的 18 个芳族中间体和离子排斥 HPLC 检测到的 6 个短线性羧酸，提出了一个合理的反应序列。SPEF 工艺促进了 Fe(III)-草酸盐配合物和其他未检测到的产物的光降解。硫酸盐和硝酸盐离子总是释放到介质中。
