气候变化领域集成服务门户(CCPortal): Fate and transport of uranium (VI) in weathered saprolite

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DOI	10.1016/j.jenvrad.2014.10.008
	Fate and transport of uranium (VI) in weathered saprolite
	Kim, Young-Jin; Brooks, Scott C.; Zhang, Fan; Parker, Jack C.; Moon, Ji-Won; Roh, Yul
通讯作者	Brooks, SC (通讯作者)
发表日期	2015
ISSN	0265-931X
EISSN	1879-1700
起始页码	154
结束页码	162
卷号	139
英文摘要	Batch and column experiments were conducted to investigate sorption and transport of uranium (U) in the presence of saprolite derived from interbedded shale, limestone, and sandstone sequences. Sorption kinetics were measured at two initial concentrations (C-0; 1, 10 mu M) and three soil:solution ratios (R-s/w; 0.005, 0.25, 2 kg/L) at pH 4.5 (pH of the saprolite). The rate of U loss from solution (mu mole/L/h) increased with increasing R-s/w. Uranium sorption exhibited a fast phase with 80% sorption in the first eight hours for all C-0 and R-s/w values and a slow phase during which the reaction slowly approached (pseudo) equilibrium over the next seven days. The pH-dependency of U sorption was apparent in pH sorption edges. U(VI) sorption increased over the pH range 4-6, then decreased sharply at pH > 7.5. U(VI) sorption edges were well described by a surface complexation model using calibrated parameters and the reaction network proposed by Waite et al. (1994). Sorption isotherms measured using the same R-s/w and pH values showed a solids concentration effect where U(VI) sorption capacity and affinity decreased with increasing solids concentration. This effect may have been due to either particle aggregation or competition between U(VI) and exchangeable cations for sorption sites. The surface complexation model with calibrated parameters was able to predict the general sorption behavior relatively well, but failed to reproduce solid concentration effects, implying the importance of appropriate design if batch experiments are to be utilized for dynamic systems. Transport of U(VI) through the packed column was significantly retarded. Transport simulations were conducted using the reactive transport model HydroGeoChem (HGC) v5.0 that incorporated the surface complexation reaction network used to model the batch data. Model parameters reported by Waite et al. (1994) provided a better prediction of U transport than optimized parameters derived from our sorption edges. The results presented in this study highlight the challenges in defining appropriate conditions for batch-type experiments used to extrapolate parameters for transport models, and also underline a gap in our ability to transfer batch results to transport simulations. (C) 2014 Elsevier Ltd. All rights reserved.
关键词	SOLUTE TRANSPORT BLIND PREDICTION ADSORPTION SORPTION SURFACE URANYL GOETHITE KINETICS U(VI)GROUNDWATER
英文关键词	Uranium(VI); Transport; Modeling; Saprolite
语种	英语
WOS研究方向	Environmental Sciences & Ecology
WOS类目	Environmental Sciences
WOS记录号	WOS:000347596000017
来源期刊	JOURNAL OF ENVIRONMENTAL RADIOACTIVITY
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/258586
推荐引用方式 GB/T 7714	Kim, Young-Jin,Brooks, Scott C.,Zhang, Fan,et al. Fate and transport of uranium (VI) in weathered saprolite[J]. 中国科学院青藏高原研究所,2015,139.
APA	Kim, Young-Jin,Brooks, Scott C.,Zhang, Fan,Parker, Jack C.,Moon, Ji-Won,&Roh, Yul.(2015).Fate and transport of uranium (VI) in weathered saprolite.JOURNAL OF ENVIRONMENTAL RADIOACTIVITY,139.
MLA	Kim, Young-Jin,et al."Fate and transport of uranium (VI) in weathered saprolite".JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 139(2015).