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|標題:||Adsorption and thermal desorption of Cr(VI) on Li/Al layered double hydroxide|
|期刊/報告no：:||Colloids and Surfaces a-Physicochemical and Engineering Aspects, Volume 277, Issue 1-3, Page(s) 8-14.|
|摘要:||Li/Al layered double hydroxide (Li/Al LDH), known as anionic clay, comprises positive charges, which are counter-balanced by interlayer anions. The material is capable of adsorbing anions through ion-exchange reaction. This property of LDH leads to its potential application in scavenging anionic contaminants, such as Cr(VI) in the waste streams. In this study, the adsorption of Cr(VI) by Li/Al LDH was investigated at 10 and 30 degrees C. The results showed that Cr(VI) adsorption was relatively rapid; however, a portion of adsorbed Cr(VI) was released over the reaction time and the releasing rate was dependent on reaction temperature. Particularly at 30 degrees C as high as 80.1% of adsorbed Cr(VI) was released after 24 h reaction. The release of adsorbed Cr(VI) is due to the deintercalation of Li+ from Li/Al LDH structures in aqueous Solution and gibbsite, which wits used as the precursor to synthesize Li/Al LDH, was the product of the deintercalation reaction. The Li deintercalation reaction of Li/Al LDH and its dependence on temperature may be utilized to develop a method of treating Cr(VI)-containing wastes and recovering Cr(VI). That is, Li/Al LDH can be used as an adsorbent to remove Cr(VI) in wastewater. Then the Cr(VI)-bearing LDH particles are collected and re-suspended in hot water to enhance Li deintercalation and Cr(VI) desorption. Consequently Cr(VI) can be recovered from the solution and the solid product, i.e., gibbsite, can be recycled for further uses. (c) 2005 Elsevier B.V. All rights reserved.|
|Appears in Collections:||土壤環境科學系|
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