石墨烯复合活性碳纤维气体扩散电极对甲基橙的降解性能

Degradation of methyl orange using reduced graphene combined activated carbon fiber gas diffusion electrode

采用超声-浸渍法制备石墨烯(GO)复合活性碳纤维(ACF)气体扩散电极,对其微观形貌、表面元素及表面官能团等进行表征,通过甲基橙批量降解处理实验阐述阴极双氧水产生性能与机理。结果表明,制备条件GO与聚四氟乙烯分散液(PTFE)质量比为1:4、GO浆液中无水乙醇添加量100 mL、煅烧温度360℃、煅烧时间10 min得到的电极性能最优,GO/ACF较ACF在45 min电催化反应甲基橙降解率提升了21.11%,双氧水最终的质量浓度提高了4.65倍,GO/ACF对甲基橙的最终降解率为100.0%,扫描电子显微镜微观形貌表征结果表明,石墨烯可均匀负载于活性碳纤维表面,X-射线光电子能谱、傅里叶变幻红外光谱仪、循环伏安及电化学阻抗测试结果表明,石墨烯复合增加了电极表面C=O官能团含量,电极电阻减小了40.06%,有利于产生H_(2)O_(2)。对初始电压、电解质浓度影响降解因素进行了优化,使用10次后GO/ACF对甲基橙降解率仍保持在100.0%、甲基橙废水COD去除率仅下降了4.45%,表明GO/ACF具有较高循环稳定性。以上研究结果可为印染废水电催化高效脱色处理与有机污染物氧化降解提供理论依据与技术借鉴。

The ultrasonic-impregnation method was used to prepare the graphene(GO)combined activated carbon fiber(ACF)gas diffusion electrode,and its micro-morphology,surface elements,and surface functional groups were characterized.The batch tests of methyl orange degradation were conducted to clarify the performance and mechanism of hydrogen peroxide production at cathode.The experimental results showed that the optimal electrode performance occurred when the mass ratio of GO to polytetrafluoroethylene dispersion(PTFE)was 1:4,the amount of anhydrous ethanol added to GO slurry was 100 mL,the calcination temperature was 360℃,and the calcination time was 10 min.After 45 min of the electrocatalytic reaction,the degradation rate of methyl orange by GO/ACF increased by 21.11%compared with ACF,the final mass concentration of hydrogen peroxide increased by 4.65 times,and the degradation rate of methyl orange by GO/ACF reached 100.0%.The microscopic morphology observation of scanning electron microscopy showed that graphene could be uniformly loaded on the surface of activated carbon fibers.According to the analysis of X-ray photoelectron spectroscopy,Fourier transform infrared spectroscopy,cyclic voltammetry,and electrochemical impedance testing results,graphene combination increased the content of C=O functional groups on the electrode surface and decreased electrode resistance by 40.06%,which was conducive to H_(2)O_(2) production.The initial voltage and degradation factors of electrolyte concentration were optimized.After 10 recycles,GO/ACF still degrade methyl orange completely,while the CODCr removal rate of methyl orange wastewater only decreased by 4.45%,which indicated that GO/ACF had a good cycling stability.The results of the study can provide a theoretical basis and technical reference for highly efficient decolorization treatment of printing and dyeing wastewater by the electro-catalysis and the oxidative degradation of organic contaminants.