ISSN 1070-4272, Russian Journal of Applied Chemistry, 2016, Vol. 89, No. 6, pp. 969−974. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © N.V. Yudina, E.V. Mal’tseva, A.S. Smirnova, E.M. Berezina,
2016, published in Zhurnal Prikladnoi Khimii, 2016, Vol. 89, No. 6, pp. 812−818.
Colloid-Chemical Properties and Physiological Activity
of Water-Soluble Humic Preparations
N. V. Yudina
, E. V. Mal’tseva
, A. S. Smirnova
, and E. M. Berezina
Institute of Petroleum Chemistry, Siberian Branch, Russian Academy of Sciences,
Akademicheskii pr. 3, Tomsk, 634021 Russia
Tomsk State University, pr. Lenina 36, Tomsk, 634050 Russia
Received June 10, 2016
Abstract—Conditions were found for solid-phase mechanochemical activation of coals, allowing a signiﬁ cant
increase in the yield of water-soluble humic preparations enriched in humic acids and mineral elements. The humic
preparations are characterized by a decrease in the molecular mass and by changes in the ionic composition and
surface activity. The physiological activity of the humic preparations was determined.
Among natural growth stimulants, humic prepara-
tions are characterized by certain physiological effect.
They enhance the general nonspeciﬁ c resistance of
plants and the plant growth, primarily the growth of the
root system and then the growth of the shoots [1, 2].
Humic acids (HAs) containing –СООН and –ОН func-
tional groups and exhibiting protonophore functions
stimulate the growth and breathing of plants.
HAs enhance the uptake of mineral nutrition ele-
ments in the form of cations and anions through the root
system. As shown in , the HA supply into the intracel-
lular space of plants is associated with the HA adsorp-
tion and transformation on the root surface. Owing to
the presence of hydrophobic and hydrophilic fragments,
humic acids are surfactants. The amount of HAs taken
up by the cells increases with an increase in the HA sur-
face activity. Chemical modiﬁ cation of the HA structure
increases the amount of functional groups and thus en-
hances the surface activity .
Traditional technologies for producing humic prepa-
rations involve preliminary chemical oxidation followed
by extraction with large volumes of highly concentrated
alkali solutions on heating. The problem can also be
successfully solved using mechanochemical methods
that allow active states to be formed in the solid state
and the reaction to be performed directly between the
reactants without their dissolution [5–8]. The mechani-
cal action can lead to the generation of free radicals and
deformed bonds favoring the occurrence of hydrogena-
tion, hydrolysis, carboxylation, sulfonation, and other
reactions enhancing the surface activity .
In this study we examined the colloid-chemical
properties and physiological activity of mechanically
activated humic preparations.
Humic preparations were obtained from oxidized
coal (OC). The ash residue of the oxidized coal reaches
16.7%, and the moisture content is 16.8 wt %.
Humic acids were isolated from coals by treating then
with 0.1 N NaOH (150 mL per gram of coal) at 90°С
for 1 h (HAOC, sample no. 1). The alkali extraction was
repeated thrice. Humic acids were precipitated from the
alkali solution by acidiﬁ cation with 4% НCl to pH 2. The
brown amorphous HA precipitate was separated by cen-
trifugation, washed with distilled water to pH 7, and dried
in a Petri dish in a vacuum oven to constant weight.