| DOI: | 10.2172/982996
|
| 报告号: | None
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| 报告题名: | Novel Anionic Clay Adsorbents for Boiler-Blow-Down Waters Reclaim and Reuse |
| 作者: | Muhammad Sahimi; Theodore Tsotsis
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| 出版年: | 2010
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| 发表日期: | 2010-01-08
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| 国家: | 美国
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| 语种: | 英语
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| 中文主题词: | PH
; 扩散
; PH值
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| 主题词: | PH
; DIFFUSION
|
| 英文摘要: | Arsenic (As) and Selenium (Se) are found in water in the form of oxyanions. Relatively high concentrations of As and Se have been reported both in power plant discharges, as well as, in fresh water supplies. The International Agency for Research on Cancer currently classifies As as a group 1 chemical, that is considered to be carcinogenic to humans. In Phase I of this project we studied the adsorption of As and Se by uncalcined and calcined layered double hydroxide (LDH). The focus of the present work is a systematic study of the adsorption of As and Se by conditioned LDH adsorbents. Conditioning the adsorbent significantly reduced the Mg and Al dissolution observed with uncalcined and calcined LDH. The adsorption rates and isotherms have been investigated in batch experiments using particles of four different particle size ranges. As(V) adsorption is shown to follow a Sips-type adsorption isotherm. The As(V) adsorption rate on conditioned LDH increases with decreasing adsorbent particle size; the adsorption capacity, on the other hand, is independent of the particle size. A homogeneous surface diffusion model (HSDM) and a bi-disperse pore model (BPM) - the latter viewing the LDH particles as assemblages of microparticles and taking into account bulk diffusion in the intraparticle pore space, and surface diffusion within the microparticles themselves - were used to fit the experimental kinetic data. The HSDM estimated diffusivity values dependent on the particle size, whereas the BPM predicted an intracrystalline diffusivity, which is fairly invariant with particle size. The removal of As(V) on conditioned LDH adsorbents was also investigated in flow columns, where the impact of important solution and operational parameters such as influent As concentration, pH, sorbent particle size and flow rate were studied. An early breakthrough and saturation was observed at higher flow rates and at higher influent concentrations, whereas a decrease in the sorbent particle size and a decrease in influent pH resulted in an increase in the bed volumes treated at breakthrough. Both the HSDM and BPM were shown capable of predicting the column behavior. |
| URL: | http://www.osti.gov/scitech/servlets/purl/982996
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| Citation statistics: |
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| 资源类型: | 研究报告
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/39943
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| Appears in Collections: | 过去全球变化的重建
影响、适应和脆弱性
科学计划与规划
气候变化与战略
全球变化的国际研究计划
气候减缓与适应
气候变化事实与影响
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| File Name/ File Size |
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Version |
Access |
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| 982996.pdf（2367KB） | 研究报告 | -- | 开放获取 | | View
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| Recommended Citation: | |
Muhammad Sahimi,Theodore Tsotsis. Novel Anionic Clay Adsorbents for Boiler-Blow-Down Waters Reclaim and Reuse. 2010-01-01.
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