Effect of Specific Active Chlorine Species and Temperature on the Electrochemical Degradation of the Reactive Blue 19 Dye Using a Boron-Doped Diamond or DSA Anode in a Flow Reactor
Effect of Specific Active Chlorine Species and Temperature on the Electrochemical Degradation of the Reactive Blue 19 Dye Using a Boron-Doped Diamond or DSA Anode in a Flow Reactor
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DOI：
10.1007/s12678-013-0156-z
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发表时间：
2013
期刊：
影响因子：
3.1
通讯作者：
Alan H. Degaki;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：
Alan H. Degaki;Gabriel F. Pereira;R. Rocha‐Filho;N. Bocchi;S. Biaggio
采用尺寸稳定阳极（DSA - Ti/TiO2RuO2）和掺硼金刚石（Nb/BDD）两种氧化能力明显不同的阳极，对存在或不存在氯离子的活性氯（Cl2、HClO或ClO -）和温度对活性蓝19染料（RB-19）溶液（500 mg L-1in 0.1 mol L-1Na2SO4）降解的影响进行了恒流电解研究。在溶液中没有氯离子的情况下（pH 6.0和25℃），Nb/BDD阳极由于其更高的氧化能力，对RB-19染料的脱色效果明显优于DSA阳极。然而，当氯离子介导的电氧化（在染料溶液中加入2g L-1NaCl）进行脱色时，两种阳极的性能都得到了显著提高，但DSA阳极的脱色率更高，特别是在pH为1.0时，cl2是溶液中的主要活性氯种；实际上，在10°C时脱色率最高，此时cl22在溶液中的溶解度增加。显然，cl2是最容易氧化RB-19分子的蒽醌发色团中心的活性氯。还分析了氯化物介导的RB-19染料溶液（pH 6.0和25°C）的COD消减率；现在阳极的氧化能力再次至关重要，Nb/BDD表现出明显优越的性能，因为羟基自由基在有机物的氧化中起着至关重要的作用，超过了活性氯的可能。
Galvanostatic electrolyses were carried out to investigate the effect of specific active chlorine species (Cl2, HClO, or ClO–) and temperature on the degradation of reactive blue 19 dye (RB-19) solutions (500 mg L–1in 0.1 mol L–1Na2SO4), in the presence or absence of chloride ions, using two anodes of markedly different oxidation power: dimensionally stable anode (DSA — Ti/TiO2RuO2) or boron-doped diamond (Nb/BDD). In the absence of chloride ions in solution (at pH 6.0 and 25 °C), the Nb/BDD anode, due to its higher oxidation power, was notably more effective in decolorizing the RB-19 dye than the DSA anode. Yet, when this decolorization was carried out by chloride-mediated electrooxidation (2 g L–1NaCl added to the dye solution), both anodes presented significantly enhanced performances, but now greater decolorization rates were attained with the DSA anode, especially at pH 1.0, when Cl2is the predominant active chlorine species in solution; actually, the highest decolorization rates are attained at 10 °C, when the Cl2solubility in solution increases. Clearly, Cl2is the active chlorine species that most readily oxidizes the anthraquinone chromophore center of the RB-19 molecule. The rate of chloride-mediated COD abatement of the RB-19 dye solution was also analyzed (at pH 6.0 and 25 °C); now the oxidation power of the anode is again paramount and Nb/BDD presents a significantly superior performance, because hydroxyl radicals play a crucial role in the oxidation of organics, beyond that possible for the active chlorine species.