Detail publikace

Acid-base properties of fractionated humic acids

KLUČÁKOVÁ, M. PILNÝ, O.

Originální název

Acid-base properties of fractionated humic acids

Typ

článek v časopise - ostatní, Jost

Jazyk

angličtina

Originální abstrakt

Humic acids (HA) were fractionated by their dissolution in universal buffers (NaOH, H3BO3, H3PO4 and CH3COOH) with various pH-values. Obtained fractions were characterized by UV/VIS and FT-IR spectroscopy and their acid-base properties were studied. It was found that contain of acidic groups in majority of individual fractions is higher than the content of original HA samples. Our hypothesis is that HA structure is changed during fractionation. HA can interact with individual components of buffer and re-arranged their structure, which results in apparently higher acidity of obtained fractions. The re-arrangement of HA structure probably causes, that some acidic groups inside HA aggregates, which are not able dissociate in original HA sample, can contribute to measured acidity in individual fractions. Surprising result is that residue after dissolving original HA in very alkaline buffer (pH = 12) has after fractionation (and "exhaustion" of the largest amount of HA fraction) several times higher solubility in water as others. On the other hand, this fact corresponds with our hypothesis of re-arrangement and possible interactions with buffer, because the most "aggressive" buffer caused the most marked changes in HA properties.

Klíčová slova

humic acids, fractionation, acid-base properties

Autoři

KLUČÁKOVÁ, M.; PILNÝ, O.

Rok RIV

2008

Vydáno

9. 9. 2008

Místo

Brno

ISSN

1213-7103

Periodikum

Chemické listy

Ročník

102

Číslo

S

Stát

Česká republika

Strany od

s1156

Strany do

s1157

Strany počet

2