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	Kinetics of silicate sorption on magnetite and maghemite: An in situ ATR-FTIR study
	Yang, Xiaofang; Roonasi, Payman; Jolstera, Rickard; Holmgren, Allan
	2009
会议名称	22nd Conference of the European-Colloid-and-Interface-Society
会议日期	AUG 31-SEP 05, 2008
会议地点	Cracow, POLAND
关键词	Silicate sorption Magnetite Maghemite In situ ATR-FTIR
英文摘要	Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy was used to monitor the in situ sorption of sodium metasilicate from aqueous solution onto synthesized magnetite and maghemite particles in the pH range of 10.8-7.0 using silicate concentrations between 0.1 mM and 5 mM. The spectral data showed that both pH and silicate concentration had great influence on the interfacial reaction between soluble silicate and the iron oxide surfaces, regarding the amount adsorbed per unit mass of iron oxide and the surface species formed. A pH dependent sorption of silicate on iron oxides was observed, implying that a maximum sorption took place in the pH range of 9.5-7.0. All experiments showed a fast initial increase in the absorption intensity followed by a slower sorption stage which was strongly dependent on the concentration of silicate in solution and the pH value. The amount of sorption onto magnetite was 3-5 times larger than onto maghemite, but there was no significant difference in the line shape of corresponding absorption bands. At pH 8.5 and low concentration (<= 0.1 mM), the silicate monomers dominate in solution and on the iron oxide Surface also monomeric species were dominating as evident from the infrared band at 950 cm(-1). However, at higher concentration (0.4-5.0 mM), the dominating absorption band at about 1000 cm(-1) shifted to higher frequency during the sorption indicating that oligomeric surface silicate species were formed on the iron oxide surface. Desorption of silicate from the surface of the iron oxides was easier to accomplish at low silicate concentration, whilst the highest concentration showed a comparatively low relative amount of desorbed silicate, suggesting that polymerized species had a stronger affinity for the iron oxide surface as compared to monomeric species. (C) 2009 Elsevier B.V. All rights reserved.
ISSN号	0927-7757
内容类型	会议论文
源URL	[http://ir.rcees.ac.cn/handle/311016/24678]
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	Yang, Xiaofang,Roonasi, Payman,Jolstera, Rickard,et al. Kinetics of silicate sorption on magnetite and maghemite: An in situ ATR-FTIR study[C]. 见:22nd Conference of the European-Colloid-and-Interface-Society. Cracow, POLAND. AUG 31-SEP 05, 2008.

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