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Competition and surface conditioning alter the adsorption of phenolic and amino acids on soil minerals
Author(s) -
Gao J.,
Jansen B.,
Cerli C.,
Helmus R.,
Mikutta R.,
Dultz S.,
Guggenberger G.,
Kalbitz K.
Publication year - 2017
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/ejss.12459
Subject(s) - goethite , adsorption , chemistry , montmorillonite , kaolinite , bentonite , inorganic chemistry , clay minerals , oxide minerals , nuclear chemistry , organic chemistry , mineralogy , chemical engineering , chemical reaction , engineering
Summary Adsorptive interactions of organic molecules with soil minerals often impair their bioavailability. However, little is known about the adsorption behaviour of phenolic and nitrogenous compounds on different minerals and their mutual interaction with respect to competition and surface conditioning (i.e. surface modification induced by preceding adsorption of the other class of compounds). Therefore, batch adsorption experiments were done to study the interaction between phenolic acids ( PA s; salicylic acid, S al; syringic acid, S yr; ferulic acid, F er; vanillic acid, V an) and amino acids ( AA s; lysine, L ys; glutamic acid, G lu; leucine, L eu; phenylalanine, P he) during adsorption on goethite and C a 2+ ‐montmorillonite at p H 6 by applying adsorbate concentrations of 0.01, 0.05 and 0.1 m m . Larger adsorption of PA s was observed on goethite than montmorillonite, whereas the phyllosilicate was a better adsorbent for AA s than the oxide. Among all tested PA s, S al was preferentially adsorbed on both minerals. For the AA s, G lu was preferentially adsorbed on goethite and L ys on montmorillonite. The AA s were more competitive than PA s and partially suppressed the adsorption of PA s on both minerals. The adsorption of PA s or AA s on both minerals was enhanced by surface conditioning with the other group, with larger effects for goethite than montmorillonite. For goethite, surface conditioning by PA s enhanced the adsorption of AA s more (by 97–161%) than did AA s for PA s (9–48%). The results support the hypothesis that pre‐adsorption of one class of organic compound can enhance the retention of another class. This suggests that adsorbed organic matter on soil mineral phases might be subject to a self‐strengthening effect. Highlights Phenolic acids ( PA s) were preferentially retained on goethite. Amino acids ( AA s) were preferentially retained on montmorillonite. AA s were more competitive than PA s for adsorption sites on both minerals. Pre‐adsorption of one class of compound can enhance the retention of another class.