Novel Anionic Clay Adsorbents for Boiler-Blow-Down Waters Reclaim and Reuse

doi:10.2172/982996

GSTDTAP > 地球科学

DOI	10.2172/982996
报告编号	None
来源ID	OSTI ID: 982996
	Novel Anionic Clay Adsorbents for Boiler-Blow-Down Waters Reclaim and Reuse
	Muhammad Sahimi; Theodore Tsotsis
	2010-01-08
出版年	2010
语种	英语
国家	美国
领域	地球科学
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.
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来源平台	US Department of Energy (DOE)
引用统计
文献类型	科技报告
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/5007
专题	地球科学
推荐引用方式 GB/T 7714	Muhammad Sahimi,Theodore Tsotsis. Novel Anionic Clay Adsorbents for Boiler-Blow-Down Waters Reclaim and Reuse,2010.