Adsorption of L-lysine on montmorillonite

作者：Parbhakar Anita; Cuadros Javier^*; Sephton Mark A; Dubbin William; Coles Barry J; Weiss Dominik

来源：Colloids and Surfaces A: Physicochemical and Engineering Aspects , 2007, 307(1-3): 142-149.

DOI：10.1016/j.colsurfa.2007.05.022

• adsorption
• amino acid
• infrared montmorillonite
• X-ray diffraction

Amino acid adsorption on smectite is relevant to prebiotic processes involving possible catalytic reactions in the early Solar System, as implied by the clay-organic correlation found in meteorites, and the generation and modification of organic components essential for the origin of life. Here we report the results of a study investigating the adsorption Of L-lysine (0.025-0.4 M) onto montmorillonite. The reaction products were studied using X-ray diffraction, chemical analysis and infrared spectroscopy. We find that lysine adsorption is first dominated by cation exchange and then by adsorption of electrically neutral lysine (as a zwitterion), as indicated by chemical and FTIR evidence. At the maximum concentration, lysine displaces only similar to 1/3 of the original interlayer cations. The d-spacing of the smectite-lysine complex increases from 1.2 to 2.1 mn as more lysine enters the interlayer space, and water is expelled. We propose a structural model of lysine sorption in the interlayer in which lysine is oriented at > 45-90 degrees to the plane of siloxane O atoms.

• 出版日期2007-10-15