混凝污泥的资源化回收及其电化学性能

Recovery of coagulated sludge and its electrochemical performance

将混凝污泥碳化后制成电极材料,通过红外光谱和X射线衍射对污泥的官能团结构与晶型进行表征,采用循环伏安和线性扫描伏安法研究不同碳化温度下所制电极材料的电化学性能,并应用于电芬顿体系催化降解双酚A。结果表明,混凝污泥的主要成分为含碳和铁元素的复合物,高温碳化后污泥的结晶度增强。所制电极在电芬顿体系中显示出良好的电催化活性。外部投加Fe2+条件下,经900℃碳化的电极材料为阴极对双酚A的去除率最高,电解130 min后去除率高达99.2%。表明在电化学芬顿法废水处理中有一定的应用前景。

The resource utilization of coagulated sludge has a strong application potential. In this work, the actual coagulated sludge was recycled and carbonized at different temperatures to prepare electrode materials. The functional group structure and crystal form of sludge materials were characterized by Fourier transform infrared spectroscopy(FT-IR) and X-ray diffraction(XRD). The electrochemical properties of sludge electrode materials carbonized at different temperatures were studied by cyclic voltammetry(CV) and linear sweep voltammetry(LSV), and their electrocatalytic activities were evaluated and compared. Coagulated sludge treated by carbonization at high temperature was efficiently recovered and reused as high-performance cathode in electrochemical field, which was applied to the catalytic degradation of bisphenol A(BPA) in the Electro-Fenton system. The results showed that the main composition of coagulated sludge was carbon-iron complex, the crystallinity of sludge increased after carbonization at high temperature. According to evaluation by electrochemical characterization, the sludge treated by carbonization had a good hydrogen peroxide(H2 O2) selectivity and yield. The selectivity of sludge electrodes carbonized at different temperatures for hydrogen peroxide in oxygen reduction reaction(ORR) process was more than 38%, the carbonized sludge presented a more rigorous two-electron transfer pathway and increased H2O2 selectivity. The removal rate of BPA increased by carbonized sludge material. Especially, coagulated sludge carbonized at 900 ℃ achieved 99.2% BPA removal in 130 min under the condition of adding Fe2+, due to its highly active two-electron reduction of oxygen(O2). The kinetics of BPA degradation by sludge material electrode was fitted, it was found that the kinetics of pollutant removal accorded with the first-order kinetics. The electrochemical characteristics of carbonized sludge electrode materials showed the possibility of their application in wastewater treatment by Electro-Fenton process. Also, a new way of synergistic treatment of sludge and wastewater pollutants has been developed, which has certain guiding significance in environmental treatment and sludge recovery.