Meng Guangcai, Wang Yanqiu, Li Xiao, Zhang Huan, Zhou Xinyu, Bai Zhongteng, Wu Lizhuo, Bai Jinfeng
School of Chemical Engineering, University of Science and Technology Liaoning, Anshan, People's Republic of China.
Environ Technol. 2022 Jan;43(4):500-513. doi: 10.1080/09593330.2020.1795931. Epub 2020 Jul 23.
Landfill leachate evaporation concentrate (LLEC) is difficult to treat due to its complex pollutant composition, which involves large amount of organic matter and inorganic salts such as scaling ions. Because of its high conductivity and high chloride-ion content, this study employed the modified electro-Fenton method with a self-developed iron-loaded cathode to treat LLEC wastewater. The operating variables were optimized according to the response surface methodology where the chemical oxygen demand (COD) removal efficiency was considered as the response based on single-factor experiments. A second-order polynomial regression model was obtained, and an application experiment revealed that it could be applied to determine LLEC treatment conditions. The removal rates of COD and colour were 100% and 99.8%, respectively, under the optimal operating conditions of an initial pH of 6, electrode spacing of 1 cm and applied voltage of 9 V. Three-dimensional fluorescence spectroscopy demonstrated that the humic acid and fulvic acid pollutants were almost completely removed. Scanning electron microscopy and energy dispersive spectroscopy analysis showed that the iron catalyst was loaded in activated carbon pores and exhibited almost no consumption during the reaction, which effectively solved the problem of iron sludge precipitation caused by electro-Fenton oxidation technology. The atomic distribution in the crystal was also analyzed by X-ray diffraction. The specific energy consumption of electrochemical oxidation was 0.498 Wh·mg COD. The results indicate that the modified electro-Fenton technique with the proposed novel cathode is an effective method for treating LLEC.
垃圾渗滤液蒸发浓缩液（LLEC）因其复杂的污染物成分而难以处理，其中含有大量有机物和诸如结垢离子等无机盐。由于其高电导率和高氯离子含量，本研究采用自行研制的载铁阴极改进型电芬顿法处理LLEC废水。基于单因素实验，以化学需氧量（COD）去除效率为响应值，根据响应面法对操作变量进行优化。得到了二阶多项式回归模型，应用实验表明该模型可用于确定LLEC的处理条件。在初始pH为6、电极间距为1 cm、施加电压为9 V的最佳操作条件下，COD和色度的去除率分别为100%和99.8%。三维荧光光谱表明，腐殖酸和富里酸污染物几乎被完全去除。扫描电子显微镜和能谱分析表明，铁催化剂负载在活性炭孔隙中，反应过程中几乎没有消耗，有效解决了电芬顿氧化技术引起的铁泥沉淀问题。还通过X射线衍射分析了晶体中的原子分布。电化学氧化的比能耗为0.498 Wh·mg COD。结果表明，所提出的新型阴极改进型电芬顿技术是处理LLEC的有效方法。
