H-binding groups in lignite vs. soil humic acids: NICA-Donnan and spectroscopic parameters
- University of Ioannina, Agrinion (Greece). Physical Chemical Laboratory
A comparative study has been carried out for two sets of humic acids isolated from lignites and soils. H-binding data were analyzed using the NICA-Donnan model, for three Greek lignite humic acids (HA) plus IHSS Leonardite reference HA, and five Greek soil HAs plus a commercial peat HA. {sup 13}C-CP-MAS NMR and H-binding data provide quantitative estimates for functional groups, showing that lignite HAs of diverse origin have strikingly homogeneous properties, while the H-binding structural units of soil HAs are characterized by a large degree of variability. Consistent differences between soil HA vs. lignite HA are revealed at the level of functional groups' concentrations. In the pH range 4 to 10, soil HA showed a charge variation < 3 (equiv kg{sup -1}) while lignite HAs showed a higher charge variation > 3.5 (equiv kg{sup -1}).
- OSTI ID:
- 21150708
- Journal Information:
- Journal of Colloid and Interface Science, Vol. 332, Issue 1; ISSN 0021-9797
- Country of Publication:
- United States
- Language:
- English
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