PEI/MWCNT修饰含铁电芬顿电极处理印染废水的研究

An Iron-doped Cathode with PEI/MWCNT Modified Carbon Felt Outer Layers for Dyeing Wastewater Treatment by Electro-Fenton System

以褐铁矿粉为铁源,用聚乙烯亚胺/多壁碳纳米管(polyethylenimine/multi-walled carbon nanotube,PEI/MWCNT)修饰石墨毡为外层,制备含铁电芬顿阴极。PEI/MWCNT修饰层可使石墨毡电还原产生H2O2的能力增强:在阴极电位为-0.95 V(vs.SCE)、曝气速率为200 m L/min的条件下,90分钟反应器内H2O2的积累量为66.5±2.4 mg/L,比普通石墨毡阴极提高56.8%。PEI/MWCNT修饰层具有较好的稳定性,连续使用20个周期,修饰石墨毡电还原产生H2O2的能力未发生明显变化。采用以制备电极为阴极的电芬顿体系处理橙Ⅱ染料模拟废水,结果表明:橙Ⅱ染料初始浓度为20 mg/L,在近中性(初始p H为6~7)条件下,60分钟内降解效率为96.8%;制备电极具备一定稳定性,可重复使用多次。最后对以制备电极为阴极的电芬顿体系处理实际印染废水的能力进行测试,在近中性条件下电解2小时后,废水色度去除率为91.7%,COD去除率为69.4%,氨氮去除率为56.2%。

An iron-doped（using limonite as the source of iron） cathode with PEI/MWCNT（polyethylenimine/Multiwalled carbon nanotube） modified carbon felt outer layers was prepared for Electro-Fenton systems. PEI/MWCNT multi-layers could significantly increase the production of H2O2. The highest H2O2 accumulation was achieved up to 66.5 ± 2.4 mg/L at-0.95 V, neutral pH and 200 mL/min of aeration rate, which increased about 56.8% than the carbon felt at the same condition. The PEI/MWCNT multi-layers were stable enough that there was no obvious decrease in H2O2 accumulation after 20 recycles. This study tested the performance of the prepared cathode in treating the simulated dyeing wastewater. The results were as follows： Orange II with initial concentration of 20 mg/L at neutral pH（pH0=6-7） was discolored completely after 60 min electrolysis process, and the decolorizing efficiency was up to 96.8%. In addition, the prepared cathode was stable enough and could be reused without catalytic activity decrease. This study also tested the performance of the prepared cathode in treating the actual dyeing wastewater. The chroma, COD and ammonia-nitrogen removal efficiency after 120 min electrolysis process were 91.7%, 69.4%, and 56.2% respectively.