Sorption and desorption of imidazolium based ionic liquids in different soil types

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• 作者：Marianne Matzke ; Karen Thiele ; Anja Mü ; ller ; Juliane Filser
• 关键词：Ionic liquids ; Organic matter ; Clay mineral ; Smectite ; Kaolinite
• 刊名：Chemosphere
• 出版年：2009
• 出版时间：January 2009
• 年：2009
• 卷：74
• 期：4
• 页码：568-574
• 全文大小：250 K

文摘

This study investigates the influence of the two different clay minerals kaolinite and smectite as well as of organic matter on the cation sorption and desorption behaviour of three imidazolium based ionic liquids -1-butyl-3-methyl-imidazolium tetrafluoroborate (IM14 BF₄), 1-methyl-3-octyl-imidazolium tetrafluoroborate (IM18 BF₄) and 1-butyl-3-methyl-imidazolium bis[(trifluoromethyl)sulfonyl]imide (IM14 (CF₃SO₂)₂N) – in soil. The German standard soil Lufa 2.2 – a natural soil classified as a loamy sand – was the basis substrate for the different soil compositions and also served as a reference soil. The addition of organic matter and clays increases the sorption of the substances and in particular smectite had striking effects on the sorption capacity for all three ionic liquids indicating that ionic interactions play an important role for sorption and desorption processes of ionic liquids in soil. One exception was for kaolinite-containing soils and the IM14 cation: with (CF₃SO₂)₂N⁻ as an anion the sorption was identical at either 10 wt % or 15 wt % clay content, and with BF₄⁻ sorption was even lower at 15 wt % kaolinite than at 10 wt % . Desorption was weak for IM18 BF₄, presumably owing to the longer alkyl side chain. With regard to the influence of kaolinite on desorption, the same pattern was observed as it was found for the sorption of IM14 BF₄ and IM14 (CF₃SO₂)₂N.