H-binding of size- and polarity-fractionated soil and lignite humic acids after removal of metal and ash components

Environmental Science and Pollution Research
By: , and 

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Abstract

A fractionation technique, combining dialysis removal of metal and ash components with hydrofluoric acid and pH 10 citrate buffer followed by chromatography of dialysis permeate on XAD-8 resin at decreasing pH values, has been applied to lignite humic acid (lignite-HA) and soil humic acid (soil-HA). H-binding data and non ideal competitive adsorption-Donnan model parameters were obtained for the HA fractions by theoretical analysis of H-binding data which reveal a significant increase of the carboxyl and the phenolic charge for the lignite-HA fractions vs. the parental lignite humic acid (LParentalHA). The fractionated lignite-HA material consisted mainly of permeate fractions, some of which were fulvic acid-like. The fractionated soil-HA material consisted mainly of large macromolecular structures that did not permeate the dialysis membrane during deashing. Chargeable groups had comparable concentrations in soil-HA fractions and parental soil humic acid (SParentalHA), indicating minimal interference of ash components with carboxyl and phenolic (and/or enolic) groups. Fractionation of HA, combined with theoretical analysis of H-binding, can distinguish the supramolecular vs. macromolecular nature of fractions within the same parental HA.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title H-binding of size- and polarity-fractionated soil and lignite humic acids after removal of metal and ash components
Series title Environmental Science and Pollution Research
DOI 10.1007/s11356-013-2302-9
Volume 21
Issue 5
Year Published 2014
Language English
Publisher Springer
Contributing office(s) National Research Program - Central Branch
Description 9 p.
First page 3963
Last page 3971