基于三维电化学反应的兰炭废水中有机物成分分析

Analysis of Organic Composition in Semi-coking Wastewater Based on Three-dimensional Electrochemical Reaction

兰炭废水具有高化学需氧量(COD)、毒性大、可生化性差、色度高、成分复杂的特点,属于较难处理的一种工业废水。三维电化学反应(3D-ER)可以有效处理兰炭废水。首先采用石墨电极片为阴阳极、活性炭为颗粒电极构建3D-ER处理兰炭废水,探讨外加电压、活性炭(AC)投加量、pH值等因素对兰炭废水COD去除率和比能耗的影响,并得出最优工艺条件;然后通过捕获试验和石墨电极片循环稳定试验,研究3D-ER过程中主要的活性基团和石墨电极片循环稳定性;最后采用气相色谱-质谱联用(GC-MS)、傅里叶红外光谱(FT-IR)和紫外光谱(UV)对3D-ER处理前后兰炭废水中有机物成分变化进行分析。结果表明:在最佳工艺条件下,即AC投加量为10 g/L、pH值为3、外加电压为4 V时,兰炭废水COD的去除率为76.2%;3D-ER过程中羟基自由基(HO·)是主要的活性基团,石墨电极片具有较好的循环稳定性;经3D-ER处理后兰炭废水中分子量较大的芳香烃和胺类物质首先被降解,但仍有部分小分子的单环苯类物质残留在废水中。

Semi-coking wastewater is characterized by high COD,high toxicity, poor biodegradability, high chroma and complex composition, which is one kind of the refractory industrial wastewater.Three-dimensional electrochemical reaction(3D-ER) can effectively degrade semi-coking wastewater.Firstly, semi-coking wastewater is treated by 3D-ER with graphite electrodes as anode and cathode, activated carbon as particle electrode.This paper explores the factors affecting COD removal rate and specific energy consumption of 3D-ER,such as applied voltage, activated carbon(AC) dosage and pH,and further obtains the optimal conditions.Then, we investigate the main active group and the cyclic stability of the electrode by trapping test and cyclic stability test of the electrode.In the end, we analysze the organic compounds before and after the reaction by gas chromatography-mass spectrometry(GC-MS),Fourier transform infrared spectroscopy(FT-IR) and ultraviolet spectroscopy(UV).The results show that when under the optimal conditions which are AC is 10 g/L,pH is 3 and applied voltage is 4 V,the COD removal rate of semi-coking wastewater is 76.2%.Hydroxyl radical(HO·) is the main active group in 3D-ER,and graphite electrode has a better cyclic stability.The aromatic hydrocarbons and amines with larger molecular weight are degraded first, but some monocyclic benzenes remain in the solution.