title: Ion exchange of ammonium in natural and synthesized zeolites.
abstract: In this study, zeolite Na-P and Na-Y was prepared by hydrothermal treatment of the Chinese natural clinoptilolite with NaOH. The ion exchange of NH4+ into the three zeolites in the temperature range of 288-333K was also investigated, and the thermodynamic parameters were calculated. The selectivity sequence for NH4+ entering the sodium form of the three materials was Na-clinoptilolite>Na-Y>Na-P, as indicated by values of DeltaG degrees . The results demonstrated that the Si/Al molar ratio of zeolites determined the selectivity for NH4+.
authors.affiliation: College of Biology and Chemical Engineering, Jiaxing University, Jiaxin, Zhejiang 314001, PR China. yifeiwang0206@yahoo.com.cn
authors.forename: Yifei
authors.initials: Y
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Lin
authors.forename: Wenqin
authors.initials: W
authors.lastname: Pang
mesh_terms: D007474:Ion Exchange; D008855:Microscopy, Electron, Scanning; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012972:Sodium Hydroxide; D013816:Thermodynamics; D014961:X-Ray Diffraction; D017641:Zeolites / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D000644:Quaternary Ammonium Compounds; C083175:clinoptilolite; D017641:Zeolites; D012972:Sodium Hydroxide