Oxidative degradation of landfill leachate by catalysis of CeMnOx/TiO2 in supercritical water: Mechanism and kinetic study
Oxidative degradation of landfill leachate by catalysis of CeMnOx/TiO2 in supercritical water: Mechanism and kinetic study
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CeMnOx/TiO2在超临界水中催化氧化降解垃圾渗滤液：机理和动力学研究
DOI：
10.1016/j.cej.2017.08.122
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发表时间：
2018
影响因子：
15.1
通讯作者：
Wang Shuzhong
中科院分区：
文献类型：
--
作者：
Gong Yanmeng;Guo Yang;Sheehan James D;Chen Zhifeng;Wang Shuzhong
垃圾渗滤液是一种典型的含高浓度有机污染物的难处理废水。本文研究了间歇式反应器中超临界水氧化（SCWO）处理垃圾渗滤液的工艺。分析了温度（T, 450 ~ 600℃）、氧化系数（OC, 1.2 ~ 3.4）、反应时间（T, 60 ~ 600 s）和pH（4.13 ~ 8.05）对总有机碳（TOC）去除率（TRE,%）和氨氮（NH3-N）去除率（NRE,%）的影响。TRE和NRE随温度和OC的升高而显著升高。在3.4℃和600℃下，600 s后TRE达到92.5%，NRE达到50.9%。建立了考虑诱导时间的改进的TRE和NRE动力学模型，并对实验结果进行了精确的关联。甲醇与垃圾渗滤液在SCWO中具有显著的共氧化作用。在垃圾渗滤液中添加多相催化剂，提高了垃圾渗滤液中有机污染物的去除率。采用不同Ce/Mn比的浸渍法制备了铈、锰和钛的复合催化剂（CeMnOx/TiO2）。与没有催化剂的渗滤液的SCWO相比，Ce/Mn比为1:2的CeMnOx/ tio2催化剂表现出较高的催化活性和稳定性。此外，还提出了催化反应机理。假设mnox为活性组分，ceo_2为添加剂和供氧源。研究结果表明，采用高效稳定催化剂的SCWO处理垃圾渗滤液是一种很有前途的技术。
Landfill leachate is a typical refractory wastewater that contains high concentration of organic pollutants. In this work, we investigated the treatment of landfill leachate by supercritical water oxidation (SCWO) in a batch reactor. The effects of temperature (T, 450–600 °C), oxidation coefficient (OC, 1.2–3.4), reaction time (t, 60–600 s) and pH (4.13–8.05) on total organic carbon (TOC) removal efficiency (TRE,%) and ammonia nitrogen (NH3-N) removal efficiency (NRE,%) were analyzed. TRE and NRE increased remarkably with increasing temperature and OC. At 3.4 OC and 600 °C, 92.5% TRE and 50.9% NRE were achieved after 600 s. A modified kinetic model on TRE and NRE considering the induction time was developed and accurately correlated the experimental results. A significant co-oxidation effect of methanol and landfill leachate in SCWO was detected. Furthermore, heterogeneous catalysts were added to SCWO of landfill leachate to improve the removal rate of organic contaminants. A series of composite catalysts (CeMnOx/TiO2) which consisted of the cerium, manganese and titanium oxides were prepared by impregnation method with varying Ce/Mn ratio. Compared with the SCWO of leachate without catalyst, the CeMnOx/TiO2catalyst with Ce/Mn ratio of 1:2 exhibited high catalytic activity and stability. Additionally, a catalytic reaction mechanism was proposed. It was assumed that MnOxis the active component and CeO2is the additive and oxygen supplier. The results obtained from this work suggest the SCWO with high-efficiency and stable catalyst could be a promising technology for landfill leachate treatment.