【作者】 林于廉；

【导师】 龙腾锐；

【作者基本信息】 重庆大学 ， 市政工程， 2009， 博士

【摘要】 垃圾渗滤液是一种危害较大的高浓度难降解有机废水,如未经处理或处理不当就排入环境势必对填埋场周围环境及地下水造成严重污染,从而直接或间接对生态环境和人体健康造成威胁。由于渗滤液水质水量变化大,其中难去除的物质多,目前国内、国外的垃圾填埋场还没有成熟和完整的工艺可以借鉴,现有工艺的处理效能也很少能真正满足卫生填埋场渗滤液的排放要求。因此需要开发投资省、效果好的渗滤液处理技术和工艺。论文立足于渗滤液实际处理的需要,以节约成本、提高渗滤液中有机物去除率,加快反应速率、缩短反应进程为目的,探索渗滤液处理新工艺—微波催化氧化技术。论文采用共沉淀法-焙烧法、浸渍-焙烧法、固相焙烧法制备、筛选了适合于微波催化氧化的催化剂并进行了表征;对处理渗滤液效能最佳的催化剂进行了改性和改形;采用动力学模型模拟有机物浓度降解趋势,采用分子量分级分析了渗滤液中有机物的分子量变化和采用全谱扫描分析了反应过程中有机物种类的变化。催化剂制备及筛选表明,Fe-Zr催化剂是共沉淀制备筛选出的效能最佳的催化剂,用Fe-Zr催化剂处理正丁酸模拟废水,TOC去除率为75%,该催化剂活性和稳定性比较好的主要原因是Zr对催化剂进行掺和改变了催化剂的物相; Fe-O/CeO₂催化剂是浸渍法制备、筛选出的效能最佳的催化剂,用该处理正丁酸模拟废水, COD_Cr去除率为67%,该催化剂中的活性成分Fe主要以α-Fe2O3形式存在,兼有少量的CeFe2;Ni-Co-Ce-O催化剂是固相-焙烧法制备、筛选出催化效能最佳的催化剂,用该催化剂处理正丁酸模拟废水,COD_Cr去除率为68%,与高温固相所得Ni-Co-Ce-O催化剂相比,该催化剂因其拥有更多孔洞,其催化活性更高。渗滤液的水质检测（长生桥垃圾填埋场的渗滤液）表明:COD_Cr平均含量为5736mg/L,有机物以分子量小于1000的为主,占54.55%;总固体平均浓度为5477.0 mg/L,总固体中溶解态固体含量最大,占87.33%;总氮含量为2163.16 mg/L,其中氨氮为1743.62 mg/L,占80.61%;镍、铁的平均含量分别为7.18 mg/L和1.98 mg/L。采用上述三种催化剂处理垃圾渗滤液,处理效能表明:Fe-O/CeO₂催化剂是处理垃圾渗滤液效能最佳的催化剂。其最佳处理工况为:Fe-O/CeO₂投加量10g/L、H2O₂投加量22.5mL/L、微波功率800w、微波作用时间8min和水样浓度5736 mg/L,此工况所得渗滤液COD_Cr去除率为69%。催化剂改性研究表明,圆形颗粒的流动性较好,改性催化剂以A物质为掺和剂,（掺和比40%）混入Fe-O/CeO₂催化剂中,搅拌均匀并挤压成型为直径4.5mm的球形颗粒,风干后在350℃条件下焙烧4h制得。改性催化剂的平均孔径为0.56nm,孔道主要以微孔为主。用改性催化剂处理渗滤液,出水COD_Cr浓度和氨氮浓度分别为257 mg/L和99.2 mg/L,处理效能分别为94.9%和94.7%。出水氨氮、COD_Cr浓度均满足城市污水的三级排放标准。单目标物质催化剂的机理分析表明,以空气为氧化剂时,Ni-O/CeO₂催化剂的催化效能高于以Fe-O/CeO₂催化剂的催化效能;以H₂O₂为氧化剂以Fe-O/CeO₂催化剂的催化效能高于Ni-O/CeO₂催化剂的催化效能;微波催化氧化反应与常温常压催化氧化反应和水浴催化氧化反应相比大大缩短了反应时间、提高了反应效率。改性催化剂的微波催化氧化处理渗滤液的机理分析表明,对富含颗粒态有机物的渗滤液,微波催化氧化能在短时间内达到很好的预处理效果,而对溶解态有机物为主的渗滤液,渗滤液经处理后出水能达到城市污水三级排放要求。分子量分级和GC-MS试验表明,渗滤液中有机物的种类随着反应时间逐级快速递减,但有机物的去除并不是按一定比例进行,而是随分子量不同而有所不同;渗滤液的微波催化氧化反应在低温条件下进行的是有机物与H₂O₂的直接反应,微波作用加快其反应速率;高温条件下则以“芬顿”反应为主,“芬顿”反应过程中,小分子物质既是优先进行反应的物质也是最难去除的物质;固态颗粒物的存在既消耗了微波能和H₂O₂,又阻碍了小分子物质与催化剂充分接触。有机物的降解不符合Elovich方程、双常数方程、一级动力学方程、抛物线扩散方程四种动力学模型,SPSS数据处理系统拟合出氨氮、COD_Cr的降解动力学方程分别为:Y=1852.4602-442.4124t+36.8971t²-1.0152t³;Y=216.5628+5060.8354exp（-0.5431t）。更多还原

【Abstract】 Landfill leachate is a kind of toxic wastewater with high concentration of organic chemicals. It will do harm to the ecological environment and human while drain to the nearby environment without proper disposal. Effluent from domestic landfill leachate treatment process can hardly reach the demands of sanitary landfill leachate emission standards because of the geographical variability of the water quality and quantity, and feasible and applicable full-treatment techniques are lacking both at home and abroad. Economic and effective leachate treatment technology and process is in urgent demand. In order to save cost, enhance the removal efficiency of organic compounds, speed up the reaction rate and shorten the reaction process, and based on the practical need, a new technology—microwave catalytic oxidation process was applied in the thesis to treat the landfill leachate. Catalyst was obtained from different methods: coprecipitation - roasting method, impregnation - roasting method and solid phase calcination method. Compared from the lab scale experiment, a best method from the four above was selected to prepare the catalyst and characterized; modification and reshaping was applied to the catalystwith the purpose to upgrade theremoval efficiency; a kinetic model was set up to formulate the degradation trend of organic compounds, and molecular classification was used to analyze the change of organic matters molecular, besides, spectral scanning was used to analyze the change of types in organic matters.Research on catalyst preparation showed that, Fe-Zr catalyst was the best choice from coprecipitationin the degradation of n-Butyric acid analogous wastewater, the removal efficiency of total organic carbon （TOC） was 75%.Potential mechanism might be due to its enhanced activity and stability by the modified phase by doped technique; Fe-O/CeO₂ catalyst was the best one obtained by impregnation - roasting. Removal efficiency of TOC was 67%. The activated constituents wasα-Fe2O3, with CeFe2; Ni-Co-Ce-O catalysts from low-temperature performed the best one by solid phase calcination. Removal efficiency of TOC was 68% in the treatment of n-Butyric acid analogous wastewater. Compared with Ni-Co-Ce-O catalysts that obtained under high- temperature, this catalysts has higher activity due to its smaller grain diameter and more specific surface areas.Water quality of reallandfill leachate （from Changsheng Bridge landfill） were as follows: COD concentration was 5736mg/L, and the molecular weight of the majority organic matter was below 1000 and it took 54.55%; the total solid concentration was 5477.0 mg/L, among which the dissolved solid was 87.33%; total nitrogen concentration was 2163.16mg/L, among which 80.61% is ammonia, and its concentration was 1743.62 mg/L; the concentration of Ni and Fe was 7.18 mg/L and 1.98mg/L, respectively, and they existed in grain and dissolved types.Fe-O/CeO₂ catalyst was the best catalyst to treat real landfill leachate, and its best working condition was as follows: the Fe-O/CeO₂ dosage is 10g/L, H₂O₂ dosage is 22.5ml/L, microwave power was 800w, microwave irradiation time is 8min and when the COD concentration was 5736mg/L, the removal efficiency of COD_Cr was 69%.Study on catalytic modification showed that the fluidity of round granule was better than that of columnar one, the catalysts was formed from powdered to round with diameter of 4.5mm;matter a was a dope agent in the modified catalysts, which was prepared by roasting at 350℃in muffle furnace for 4h after extrusion forming and air drying . The average aperture was 0.56nm, and main duct were micropores. The leachate was filtered through 0.45μm filter after treated by modified catalysts, its effluent COD_Cr and ammonia concentration are 257mg/L and 99.2mg/L, which meets the municipal wastewater effluent standardsⅢ.Results of single-purpose matter catalysts experiment showed that the catalysis effectiveness of Ni-O/CeO₂ catalysts was higher than that of Fe-O/CeO₂; the catalysis effectiveness of Fe-O/CeO₂ catalysts was higher than that of Ni-O/CeO₂ when H₂O₂ served as oxidants. Compared with atmospheric pressure and ambient temperature catalytic oxidation and catalytic oxidation in a water bath, microwave catalytic oxidation has higher removal efficiency and greatly shortens the reaction time.The mechanism of modified Catalysts treating leachate through microwave catalytic oxidation showed that, for those rich in granular organic matters, microwave catalytic oxidation attains good pretreatment effect, while for those rich in dissolved organic matter, the effluent attained the municipal wastewater effluent standardsⅢafter treated; Molecular weigh cutting experiments showed that the removal efficiency of organic matter changes disproportionally with different molecular weight. In the early stage of catalytic reaction, compared with large molecule organic matters, the smaller one might much more easily removed by catalytic oxidation, after the catalytic oxidation reaction, large molecule organic matters in leachate were oxidized into smaller molecule organic compounds, carbon dioxide and water. Spectrum scanning was done before and after the leachate was treated, result show that the types of organic matters decreased quickly step by step as the proceeded. From the treatment efficiency, microwave catalytic oxidation is an efficient way to remove ammonia. General kinetic formular of organic degradation in this study did not show a goodness of fit with Elovich equation, Double constant equation, first-degree kinetic equation and parabola- diffusion equation. However, the fitted degradation equation by SPSS package were Y=1852.4602-442.4124t+36.8971t²-1.0152t³;Y=216.5628+5060.8354exp （-0.5431t）.更多还原