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.
J Hazard Mater. 2015 Jun 15;290:34-42. doi: 10.1016/j.jhazmat.2015.02.050. Epub 2015 Feb 19.
The decolorization and mineralization of solutions containing 230 mg L(-1) of the food azo dye Allura Red AC at pH 3.0 have been studied upon treatment by electrochemical oxidation with electrogenerated H2O2 (EO-H2O2), electro-Fenton (EF) and photoelectro-Fenton (PEF). Experiments were performed with a stirred tank reactor containing a boron-doped diamond (BDD) or Pt anode and an air-diffusion cathode to generate H2O2. The main oxidants were hydroxyl radicals formed at the anode surface from water oxidation and in the bulk from Fenton's reaction between H2O2 and added Fe(2+). The oxidation ability increased in the sequence EO-H2O2 < EF < PEF and faster degradation was always obtained using BDD. PEF process with BDD yielded almost total mineralization following similar trends in SO4(2-), ClO4(-) and NO3(-) media, whereas in Cl(-) medium, mineralization was inhibited by the formation of recalcitrant chloroderivatives. GC-MS analysis confirmed the cleavage of the −N=N− bond with formation of two main aromatics in SO4(2-) medium and three chloroaromatics in Cl(-) solutions. The effective oxidation of final oxalic and oxamic acids by BDD along with the photolysis of Fe(III)-oxalate species by UVA light accounted for the superiority of PEF with BDD. NH4(+), NO3(-) and SO4(2-) ions were released during the mineralization.
在 pH 3.0 条件下，用电化学氧化法处理含 230mg/L 食品偶氮染料诱惑红 AC 的溶液时，研究了电生成 H2O2（EO-H2O2）、电芬顿（EF）和光电芬顿（PEF）对溶液的脱色和矿化作用。实验在一个装有掺硼金刚石（BDD）或 Pt 阳极和空气扩散阴极的搅拌槽式反应器中进行，以生成 H2O2。主要氧化剂是由水氧化在阳极表面形成的羟基自由基和由 H2O2 与外加 Fe(2+)之间的芬顿反应在本体中形成的。氧化能力的顺序为 EO-H2O2<EF<PEF，使用 BDD 时总是得到更快的降解。BDD 的 PEF 工艺在 SO4(2-)、ClO4(-)和 NO3(-)介质中几乎完全矿化，遵循相似的趋势，而在 Cl(-)介质中，矿化受到形成难降解氯衍生物的抑制。GC-MS 分析证实了−N=N−键的断裂，在 SO4(2-)介质中形成了两种主要的芳烃，在 Cl(-)溶液中形成了三种氯芳烃。BDD 对最终草酸和草酰胺的有效氧化以及 UVA 光对 Fe(III)-草酸盐物种的光解解释了 BDD 的 PEF 的优越性。在矿化过程中释放了 NH4(+)、NO3(-)和 SO4(2-)离子。
