柠檬酸钠改性对沸石吸附水中低浓度碳、氮污染物的影响研究  

Influencing research of low concentration nitrogen pollutants and COD removal by sodium citrate modified zeolite

作　　者：林海[1] 刘泉利[1] 董颖博[1] 

机构地区：[1]北京科技大学土木与环境工程学院,北京100083

出　　处：《功能材料》2015年第3期3064-3068,3072,共6页Journal of Functional Materials

基　　金：国家自然科学基金资助项目(51174017)

摘　　要：研究了柠檬酸钠改性沸石后其吸附水中低浓度氨氮、硝态氮、COD等污染物的效果和吸附热力学、动力学特征,并通过比表面积与孔径分布测试、扫描电镜、X射线衍射手段测试分析了柠檬酸钠改性对沸石结构特征的影响结果。结果发现,天然沸石经柠檬酸钠改性后,其同步吸附3种污染物的效果有较大提高,其中对氨氮的去除率由53%上升到92%。对硝态氮的去除率由2%提升到10%、对COD的去除率由5%提高到35%。柠檬酸钠改性沸石后其对氨氮及COD的吸附符合Langmuir等温线,属于单层覆盖,而对硝态氮的吸附更符合Freundlich等温线。叶洛维奇吸附动力学方程在描述沸石吸附氨氮、硝态氮和COD的吸附动力学上,更具有优越性,说明沸石对3种污染物的吸附均属于化学吸附。测试分析发现,柠檬酸钠改性沸石后其组分中钠元素含量增加,表面变得比较光滑、孔径和孔体积增大,但柠檬酸钠改性并没有改变沸石的晶体结构,主要是因为引入了钠离子以及柠檬酸根的酸性作用,提高了沸石的吸附能力。The removal efficiency to ammonia nitrogen,nitrate nitrogen,COD and characteristics of adsorption thermodynamics,kinetics of zeolite modified by sodium citrate was investigated.And using specific surface area and pore analysis,SEM-EDS,XRD and other means to characterize the structure.Results showed that,the synchronous removal efficiency of zeolite modified by sodium citrate to ammonia nitrogen,nitrate nitrogen, COD were 92%,10%,35%,which had respectively increased by 53%,2%,5% as that of the natural zeolite.The adsorption equilibrium data of ammonia nitrogen and COD on sodium citrate modified zeolite fitted well to the Langmuir,nitrate nitrogen fitted well to the Freundlich isotherm models.The adsorption kinetics data of am-monia nitrogen,nitrate nitrogen,COD on modified zeolite could be well described by elovich absorption kinetic equation .The result of EDS demonstrated that sodium can be loaded on the zeolite,and the average pore width, total pore volume increased after modified sodium citrate.But the crystal structure kept invariant.

关 键 词：沸石 氨氮 硝态氮 COD 等温线 动力学 

分 类 号：X703.1[环境科学与工程—环境工程]