| K2S2O8强化g-C3N4薄膜电极光电催化降解Cu(CN)32-并同步回收Cu |
| 摘要点击 1723 全文点击 746 投稿时间：2017-06-14 修订日期：2017-08-08 |
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| 中文关键词 铜氰络合物 光电催化氧化 石墨相氮化碳 过硫酸盐 非自由基氧化 |
| 英文关键词 cyanide and copper complex photoelectrocatalytic g-C3N4 peroxydisulfate non-radical oxidation |
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| 中文摘要 |
| 采用高温液相生长法制得g-C3N4薄膜电极并作为光阳极，以石墨毡作为阴极，建立了光电催化系统.通过对比光电催化体系、K2S2O8体系以及外加K2S2O8到光电催化体系，发现在光电催化系统下外加K2S2O8可以有效地提高光电催化降解Cu（CN）32-的效率，并实现了Cu在阴极上的有效回收.探究了K2S2O8投加量对CN-降解率和Cu回收率的影响，发现当K2S2O8浓度为1 mmol·L-1，偏压为1.0 V时，CN-的去除率和Cu回收率分别达到86.23%和82.11%.通过SEM、EDS和XPS分析阴阳极表面形貌，发现部分Cu+被氧化以CuO的形式存在于沉淀和阳极表面，大部分铜离子通过电化学还原作用以单质铜的形式沉积于阴极表面，铜离子有效地从体系中去除.电子顺磁共振及淬灭实验分析表明，CN-的氧化去除是硫酸根自由基（SO4·-）氧化和非自由基氧化共同作用. |
| 英文摘要 |
| Oxidation of Cu-cyanides by a photoelectrocatalytic method was enhanced by adding peroxydisulfate (PS). In the photoelectrocatalytic system (PEC), graphitic carbon nitride (g-C3N4) thin films prepared by a liquid-based reaction and graphitic carbon felt (GCF) were used as the photoanode and cathode, respectively. First, various processes, including PEC, PS oxidation, and PEC with PS addition (PEC/PS), were compared for Cu-cyanide removal. The addition of PS improved greatly the photoelectrocatalytic efficiency for the oxidation of CN- and the recovery of Cu on the cathode. The effect of the amount of K2S2O8 was investigated in detail. The removal efficiency of CN- and Cu recovery can reach up to 86.23% and 82.11%, respectively, with 1 mmol·L-1 K2S2O8 at 1.0 V bias potential. Combined with the SEM, EDS, and XPS analysis of the electrode surface, it was concluded that the free Cu+ was oxidized and existed in the precipitation and photoanode in the form of CuO. Conversely, the liberated Cu+/Cu2+ ions were electrochemically reduced to elemental Cu on the surface of the graphitic carbon felt cathode. As a result, metal Cu was recovered from the wastewater of the copper cyanide complexes. Electron spin resonance and radical quenching experiment analysis showed that the oxidation of CN- is assigned to sulfate radical oxidation and non-radical oxidation processes. |
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