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Adsorption of L-lysine on montmorillonite
journal contributionposted on 2023-05-18, 10:15 authored by Anita Parbhakar-Fox, Cuadros, J, Sephton, MA, Dubbin, W, Coles, BJ, Weiss, D
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 ∼1/3 of the original interlayer cations. The d-spacing of the smectite–lysine complex increases from 1.2 to 2.1 nm 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◦ to the plane of siloxane O atoms.
Publication titleColloids and Surfaces A
Department/SchoolSchool of Natural Sciences
PublisherElsevier Science Bv
Place of publicationPo Box 211, Amsterdam, Netherlands, 1000 Ae
Rights statementCopyright 2007 Elsevier B.V.