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Desorption of Phosphate from Kaolinite by Citrate and Bicarbonate
Author(s) -
Nagarajah S.,
Posner A. M.,
Quirk J. P.
Publication year - 1968
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1968.03615995003200040025x
Subject(s) - bicarbonate , phosphate , chemistry , adsorption , kaolinite , inorganic chemistry , ionic strength , desorption , chloride , mineralogy , biochemistry , organic chemistry , aqueous solution
Phosphate which cannot be desorbed from kaolinite by chloride at the same pH and ionic strength at which adsorption took place is significantly desorbed by citrate and bicarbonate. In the presence of citrate or bicarbonate, phosphate adsorption by kaolinite is reduced. The extent of reduction depends on the way in which phosphate and citrate or bicarbonate are added to the clay. Maximum reduction in phosphate adsorption occurs when phosphate and citrate or bicarbonate are added together or when phosphate is introduced after citrate or bicarbonate adsorption. These effects are attributed to the fact that mole for mole exchange between phosphate and the other anion does not occur. The reduction in phosphate adsorption results not only from competition but also from a concomitant change in charge.