电极材料对高压脉冲放电处理苯酚的影响

Effects of electrode materials on phenol treatment by high voltage pulse discharge

高压脉冲放电产生的低温等离子体技术广泛应用于环境污染治理,金属电极材料会影响污染物放电处理效能。对比Fe、Cu和Al电极材料对苯酚溶液的处理效果,考察电极极性组合、溶液初始pH和电导率等反应条件对苯酚去除率和H_(2)O_(2)生成量的影响,并研究了影响机制。结果表明:在放电峰值电压20 kV、频率50 Hz、O_(2)流量2 L/min的条件下,反应65 min,不论做高压电极还是接地电极,Fe与Al对苯酚的降解率高于Cu电极,分别为90.1%、89.6%和77.0%。电极材料对苯酚降解效果的高低顺序为Al Al、Fe Fe(Fe Al、Al Fe)、Cu Al(Al Cu、Cu Cu)、Fe Cu、Cu Fe。Al电极放电后溶液中H_(2)O_(2)生成量最高,Fe电极由于芬顿反应消耗了H_(2)O_(2)。电极材料对H_(2)O_(2)的积累由多到少的顺序为Al Al、Fe Al、Al Fe(Fe Fe)、Fe Cu、Cu Fe、Cu Cu。对于Cu和Al电极,溶液碱性条件下苯酚去除率较高,而Fe电极在中性和碱性条件下处理苯酚较好。溶液电导率对3种电极处理苯酚的影响各不相同。

Low temperature plasma produced by high voltage pulse discharge has been widely used in environmental pollution control.Metal electrodes have an effect on the contaminant’s removal efficiency by plasma treatment.In this study,iron,copper and aluminum metal circular plates were used as discharge electrodes to treat the phenol solutions.The phenol removal and hydrogen peroxide production were compared with the different electrode polarity combination,initial pH and conductivity of solution.The mechanisms of electrode materials affecting phenol removal were studied.Results showed that the degradation of phenol was higher for iron and aluminum than copper.Under the condition of high-voltage discharge of 20 kV,discharge frequency of 50 Hz,oxygen flow of 2 L/min,the phenol removal was 90.1%(iron),89.6%(aluminum),and 77.0%(copper)after 65 min treatment.The order of effectiveness of the electrode materials on phenol removal was as follows:Al-Al,Fe-Fe(Fe-Al,Al-Fe),Cu-Al(Al-Cu,Cu-Cu),Fe-Cu,Cu-Fe.The amount of hydrogen peroxide in the solution after the aluminum electrode discharged was the highest,and after the iron electrode discharged was low for Fenton reaction during discharge.The order of accumulation of H_(2)O_(2)by electrode materials from more to less was as follows:Al-Al,Fe-Al,Al-Fe(Fe-Fe),Fe-Cu,Cu-Fe,Cu-Cu.For copper and aluminum electrodes,the alkaline conditions were better than neutral and acidic conditions to treat phenol,while the neutral and acidic conditions were better for iron electrode.The effects of solution conductivity on the treatment of phenol with three electrodes were different.