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Phosphate Adsorption on an Oxisol
Author(s) -
Parfitt R. L.
Publication year - 1977
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/sssaj1977.03615995004100060009x
Subject(s) - oxisol , adsorption , phosphate , goethite , gibbsite , chemistry , kaolinite , inorganic chemistry , aluminium , nuclear chemistry , mineralogy , organic chemistry , soil water , geology , soil science
Adsorption isotherms for phosphate on the A and B horizon of an oxisol from Papua New Guinea showed high affinity adsorption at low solution concentrations and a linear increase in adsorption at higher solution concentrations. Adsorption increased with decrease in pH in the range 3 to 8. Comparison with data obtained under similar conditions with synthetic goethite (α‐FeOOH) and gibbsite [Al(OH) 3 ] suggested that phosphate reacted with FeOH and FeOH 2 + groups on soil iron oxide surfaces to form a binuclear bridging FeOP(O 2 )OFe complex and with exposed Al(OH)H 2 O on kaolinite edges and on hydroxy‐aluminum species to form a binuclear or bidentate phosphate complex. At higher phosphate concentrations isotherms showed continued adsorption which may be due to a further reaction involving hydroxy‐aluminum groups.