Arsenate adsorption on an Fe-Ce bimetal oxide adsorbent: EXAFS study and surface complexation modeling

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	Arsenate adsorption on an Fe-Ce bimetal oxide adsorbent: EXAFS study and surface complexation modeling
	Dou, Xiaomin; Zhang, Yu; Zhao, Bei; Wu, Xiaomei; Wu, Ziyu; Yang, Min
	2011
会议名称	6th International Conference on Interfaces Against Pollution (IAP 2010)
会议日期	MAY 16-19, 2010
会议地点	Beijing, PEOPLES R CHINA
关键词	Arsenate Adsorption Fe-Ce bimetal oxide Surface complexes EXAFS CD-MUSIC model
英文摘要	The mechanism of arsenate (As(V)) adsorption on an Fe-Ce bimetal (hydrous) oxide (Fe-Ce) was investigated using complementary analysis techniques including extended X-ray absorption fine structure (EXAFS) and surface complexation modeling. The As K-edge EXAFS spectra showed that the second peak of Fe-Ce after As(V) adsorption was the As-Fe shell, which supported the finding that As(V) adsorption occurred mainly at the Fe surface active sites. Two As-Fe distances of 3.30 angstrom and 3.55 angstrom were observed from the EXAFS spectra of As(V) adsorbed samples at three pH levels (5.0, 7.6, and 9.0) and two initial surface loadings of 70 and 130 mg/g, which indicated that monodentate mononuclear and bidentate binuclear As surface complexes coexisted. When compared with the reported dominant species of bidentate binuclear complex for As existing on iron (hydro)oxides, the existence of Ce atoms in the bimetal oxide and the high surface loading were the likely reasons for the existence of the monodentate complex. A Charge Distribution-Multi-site Sites Complexation (CD-MUSIC) model showed that protonated monodentate (MH) and deprotonated bidentate (B) complexes preferred to exist on the Fe-Ce surface in a high surface loading range (Gamma = 5.11-14.4 mu mol/m(2)). The MH complex was shown to be dominant at pH < 8. Based on the results from EXAFS analysis and the CD-MUSIC model, the adsorptive behavior of As(V) on Fe-Ce with high surface loadings was satisfactorily interpreted and understood. (C) 2010 Elsevier B.V. All rights reserved.
ISBN号	0927-7757
WOS记录号	WOS:000289920200017
内容类型	会议论文
源URL	[http://ir.rcees.ac.cn/handle/311016/24628]
专题	生态环境研究中心_环境水质学国家重点实验室
推荐引用方式 GB/T 7714	Dou, Xiaomin,Zhang, Yu,Zhao, Bei,et al. Arsenate adsorption on an Fe-Ce bimetal oxide adsorbent: EXAFS study and surface complexation modeling[C]. 见:6th International Conference on Interfaces Against Pollution (IAP 2010). Beijing, PEOPLES R CHINA. MAY 16-19, 2010.