三维电极降解苯酚的新工艺及机理

Novel technology and mechanism of electrochemical degradation of phenol in wastewater with three-dimensional electrode reactor

开发三维电极法降解苯酚新工艺,用电化学方法研究苯酚降解的机理。结果表明：采用预处理后的活性炭作为粒子电极,在进水pH值6~7、进水流量180 mL/min、水温25℃、氯化钠加入量1 g/L、电流100 mA的条件下,电解1.5 h后总有机碳（TOC）的去除率可以达到95%以上。电解过程活性炭阳极生成羟基自由基（.OH）并吸附在活性炭上,与吸附在活性炭上的苯酚形成微电池。通过微电池反应,苯酚首先被降解成邻苯二酚、间苯二酚、对苯二酚等中间产物,进而又被矿化为CO2和H2O。同时,阳极极化曲线表明苯酚也可在阳极氧化,但羟基自由基对苯酚的降解起主要作用。

The degradation technology of phenol in wastewater via three-dimensional electrode reactor was proposed, and then the degradation mechanism of phenol was investigated by the electrochemical methods. The results show that the removal efficiency of total organic carbon （TOC） can reach 95% under conditions of pH 6-7, influent flow rate of 180 mL/min, 25 ~C, NaC1 dosage of 1 g/L, electric density of 100 mA and electrolysis time for 1.5 h, and using the pretreated activated carbon as particle electrode. The hydroxyl radicals are generated and adsorbed on the surface of activated carbon electrode during the process of electrochemical degradation. Meanwhile, the micro-batteries are formed by the radicals and adsorbed phenol. In the micro-cell, firstly phenol is degraded into the intermediates, such as catechol, resorcinol and hydroquinone, and then those intermediates are mineralized into CO2 and/-I20. Furthermore, the anodic polarization curves show that phenol can be oxidized at the anode surface. However, the hydroxyl radical is the major contributor for phenol degradation.