Boron isotopic fractionation during incorporation of boron intoMg(OH)(2)

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	Boron isotopic fractionation during incorporation of boron intoMg(OH)(2)
	Xiao Jun; Xiao YingKai; Liu CongQiang; Zhao ZhiQi; He MaoYong; Liang ChongShan
	2009
发表期刊	CHINESE SCIENCE BULLETIN
ISSN	1001-6538
卷号	54 期号:17 页码:3090-3100
关键词	Boron Incorporation Isotopic Fractionation Magnesium Hydroxide
语种	Experiments of boron incorporated into Mg(OH)(2) from magnesium-free synthetic seawater were carried out at various pH values, in order to investigate the adsorption species and the variation of isotopic fractionation of boron on Mg(OH)(2). The results showed that the incorporation of boron into Mg(OH)(2) was very rapid and reached the equilibrium after 4 h. The [B](s) and the partition coefficient K (d) between Mg(OH)(2) and final solution decreased with the increasing pH. The maximum values of [B](s) and K (d) were much higher than that of boron adsorbed on metal oxide or clay minerals, indicating that the incorporation capability of boron into Mg(OH)(2) was very strong. When the adsorption reached the equilibrium, the delta B-11(fsw) was lower than delta B-11(isw). The boron isotopic fractionation alpha (s-fsw) was between 1.0186 and 1.0220 with an average of 1.0203. All these indicated that B-11 incorporated into Mg(OH)(2) preferentially due to B(OH)(3) incorporation into Mg(OH)(2) preferentially. The deposition reaction of B(OH)(3) with Mg(OH)(2) was the direct reason for B(OH)(3) incorporation into Mg(OH)(2). During the boron incorporation into Mg(OH)(2), the isotopic fractionation characteristic of boron was decided by the simultaneous existence of adsorption of boron on Mg(OH)(2) and the deposition reaction of H3BO3 with Mg(OH)(2). Different from the fact that only B(OH) (4) (-) species incorporated into bio-carbonate, B(OH)(3) and B(OH)(4) incorporated into Mg(OH)(2) simultaneously, and B(OH)(3) incorporated into it preferentially. The lower pH is, the more incorporated fraction of B(OH)(3) will be. Mg(OH)(2) exists widely in madrepore, which influences the quantitative correspondence of the boron isotopic composition delta B-11(carb) of corals on the pH of the seawater badly, and brings serious uncertainty to the delta B-11(carb) as the indicator of the ancient seawater pH. Experiments of boron incorporated into Mg(OH)(2) from magnesium-free synthetic seawater were carried out at various pH values, in order to investigate the adsorption species and the variation of isotopic fractionation of boron on Mg(OH)(2). The results showed that the incorporation of boron into Mg(OH)(2) was very rapid and reached the equilibrium after 4 h. The [B](s) and the partition coefficient K (d) between Mg(OH)(2) and final solution decreased with the increasing pH. The maximum values of [B](s) and K (d) were much higher than that of boron adsorbed on metal oxide or clay minerals, indicating that the incorporation capability of boron into Mg(OH)(2) was very strong. When the adsorption reached the equilibrium, the delta B-11(fsw) was lower than delta B-11(isw). The boron isotopic fractionation alpha (s-fsw) was between 1.0186 and 1.0220 with an average of 1.0203. All these indicated that B-11 incorporated into Mg(OH)(2) preferentially due to B(OH)(3) incorporation into Mg(OH)(2) preferentially. The deposition reaction of B(OH)(3) with Mg(OH)(2) was the direct reason for B(OH)(3) incorporation into Mg(OH)(2). During the boron incorporation into Mg(OH)(2), the isotopic fractionation characteristic of boron was decided by the simultaneous existence of adsorption of boron on Mg(OH)(2) and the deposition reaction of H3BO3 with Mg(OH)(2). Different from the fact that only B(OH) (4) (-) species incorporated into bio-carbonate, B(OH)(3) and B(OH)(4) incorporated into Mg(OH)(2) simultaneously, and B(OH)(3) incorporated into it preferentially. The lower pH is, the more incorporated fraction of B(OH)(3) will be. Mg(OH)(2) exists widely in madrepore, which influences the quantitative correspondence of the boron isotopic composition delta B-11(carb) of corals on the pH of the seawater badly, and brings serious uncertainty to the delta B-11(carb) as the indicator of the ancient seawater pH.
文献类型	期刊论文
条目标识符	http://ir.isl.ac.cn/handle/363002/2094
专题	青海盐湖研究所知识仓储中国科学院青海盐湖研究所
推荐引用方式 GB/T 7714	Xiao Jun,Xiao YingKai,Liu CongQiang,et al. Boron isotopic fractionation during incorporation of boron intoMg(OH)(2)[J]. CHINESE SCIENCE BULLETIN,2009,54(17):3090-3100.
APA	Xiao Jun,Xiao YingKai,Liu CongQiang,Zhao ZhiQi,He MaoYong,&Liang ChongShan.(2009).Boron isotopic fractionation during incorporation of boron intoMg(OH)(2).CHINESE SCIENCE BULLETIN,54(17),3090-3100.
MLA	Xiao Jun,et al."Boron isotopic fractionation during incorporation of boron intoMg(OH)(2)".CHINESE SCIENCE BULLETIN 54.17(2009):3090-3100.