title: Simultaneous removal of ammonium and phosphate by zeolite synthesized from fly ash as influenced by salt treatment.
abstract: To develop an effective technique for enhancing the removal efficiency of ammonium and phosphate at low concentrations without losing potential removal capacity, Na-ZFA (zeolite synthesized from fly ash) was converted into Ca-, Mg-, Al-, and Fe-ZFA by salt treatment and the simultaneous removal of ammonium and phosphate by ZFA saturated with different cations was investigated. It was shown that Al3+-ZFA had the highest removal efficiencies (80-98%) for ammonium, followed by Mg2+ (43-58%), Ca2+ (40-54%), Na+ (<20%), and Fe3+ (<1%). Both alkaline pH values (in the cases of Na+, Ca2+, Mg2+) and acidic pH value (in the case of Fe3+) inhibited the sequestration of ammonium. At low initial phosphate concentrations, the efficiency of phosphate removal by Al3+- and Fe3+-ZFA approached 100%, followed by Ca2+ (60-85%), Na+ (<25%), and Mg2+ (<5%). The difference in phosphate removal efficiency was explained by the adsorption mechanisms. It was concluded that ZFA could be used in simultaneous removal of NH4+ and phosphate at low concentrations with presaturation by an appropriate cation such as Al3+ through salt treatment.
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. dywu@sjtu.edu.cn
authors.forename: Deyi
authors.initials: D
authors.lastname: Wu
authors.forename: Baohua
authors.initials: B
authors.lastname: Zhang
authors.forename: Chunjie
authors.initials: C
authors.lastname: Li
authors.forename: Zhenjia
authors.initials: Z
authors.lastname: Zhang
authors.forename: Hainan
authors.initials: H
authors.lastname: Kong
mesh_terms: D002244:Carbon / Q000737:chemistry*; D060729:Coal Ash; D007220:Industrial Waste; D052638:Particulate Matter / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012037:Refuse Disposal / Q000379:methods; D017641:Zeolites / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D060729:Coal Ash; D007220:Industrial Waste; D052638:Particulate Matter; D010710:Phosphates; D000644:Quaternary Ammonium Compounds; D017641:Zeolites; D002244:Carbon