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Sorption of Copper(II) on Aluminum Hydroxide as Affected by Phosphate
Author(s) -
McBride M. B.
Publication year - 1985
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/sssaj1985.03615995004900040011x
Subject(s) - chemisorption , adsorption , sorption , phosphate , hydroxide , inorganic chemistry , chemistry , copper , precipitation , nucleation , oxide , metal , organic chemistry , physics , meteorology
The mechanisms of Cu 2+ bonding on noncrystalline aluminum hydroxide with or without various levels of presorbed phosphate have been studied by the technique of electron spin resonance. Evidence for two separate chemisorption sites in the absence of phosphate is presented. At high levels of Cu 2+ adsorption, discrete site chemisorption is replaced by nucleation or precipitation of hydroxy‐Cu species at the surface. High levels of sorbed phosphate suppress Cu 2+ adsorption, blocking the coordination of Cu 2+ to AIOH groups on aluminum hydroxide. It is proposed that the decreased adsorption of Cu 2+ observed in this study was a result of the weaker coordination of Cu 2+ to the phosphate‐coated surface than to the alumina surface in the absence of phosphate. The enhanced adsorption of metal ions on oxide and hydroxide surfaces following phosphate sorption observed in other studies is attributed to a different mechanism, involving the formation of a ternary complex in which Cu bonds simultaneously to phosphate and the surface.