title: Toward a better understanding of coagulation for dissolved organic nitrogen using polymeric zinc-iron-phosphate coagulant.
abstract: The increase of agricultural related activities and the lack of effective waste control has led to an increase of organic nitrogen in water. The development of coagulants to effectively remove dissolved organic nitrogen (DON) is a high priority in the water treatment industry. We developed a polymeric zinc-iron-phosphate (ZnFeP) coagulant and investigated its coagulation effect on DON removal. Optimum coagulant for coagulation for DON and TDN removals was characterized by the dense convex-concave packing structure differing from other zinc-based coagulant, polycrystalline structure and high content colloidal species, which could account up to 87% of the total colloidal species. Coagulation experiments showed the DON removal rate to vary greatly depending on principal components and their interaction with metals, phosphate and hydroxyl. DON removal efficiency increased with the increase of colloidal species. The coagulation was also dependent on coagulant dosage and water quality parameters: Coagulation efficiency increased with coagulant dosage in the investigated range of 1-16 mg/l, and a pH of 6 was found to be superior for the coagulation. DON removal efficiency was also higher than and linearly correlated with total dissolved nitrogen (TDN) removal, which implies that an effective coagulation for TDN is also effective for DON. The findings in this study indicate that coagulation of DON is largely influenced by coagulant composition and species. We also found the removal of DON by our newly developed polymeric ZnFeP coagulant to be effective.
authors.affiliation: College of Civil Engineering, Hunan University of Science & Technology, Xiangtan 411201, China. Electronic address: zhuguoc@hnust.edu.cn.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Zhu
authors.affiliation: College of Civil Engineering, Hunan University of Science & Technology, Xiangtan 411201, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Civil and Environmental Engineering, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Yin
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China.
authors.forename: Zhongwu
authors.initials: Z
authors.lastname: Li
authors.affiliation: College of Civil Engineering, Hunan University of Science & Technology, Xiangtan 411201, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: College of Civil Engineering, Hunan University of Science & Technology, Xiangtan 411201, China.
authors.forename: Bozhi
authors.initials: B
authors.lastname: Ren
authors.affiliation: College of Civil Engineering, Fuzhou University, Fujian 350108, China.
authors.forename: Gongduan
authors.initials: G
authors.lastname: Fan
authors.affiliation: Department of Chemical Engineering, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Peng
authors.initials: P
authors.lastname: Wan
mesh_terms: D007501:Iron; D009584:Nitrogen; D010710:Phosphates; D018508:Water Purification; D015032:Zinc
chemical_list: D010710:Phosphates; D007501:Iron; D015032:Zinc; D009584:Nitrogen
keywords: Coagulation; Dissolved organic nitrogen; Polymeric iron-zinc-phosphate; Source water