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The effect of pH and metal binding on the transport properties of humic acids
Author(s) -
RITCHIE GERALDINE S. P.,
POSNER A. M.
Publication year - 1982
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1982.tb01762.x
Subject(s) - chemistry , metal , humic acid , hydrolysis , metal ions in aqueous solution , inorganic chemistry , dissociation (chemistry) , molecule , diffusion , organic chemistry , thermodynamics , fertilizer , physics
Summary The molecular weight, shape and size of fractionated humic acids and their metal complexes were determined from sedimentation and diffusion measurements made at various pH values. For all the species studied, the molecular weight and size decreased as the pH became more alkaline. However, the shape of the molecule (approximately spherical) was unaffected by pH. The molecular weight and size of the metal humates depended not only on the type of cation but also on the degree of dissociation ofthe humic acid and the hydrolysis ofthe metal ion.