C - Lublin

MINERAL-ORGANIC COMPOUND OF SOILS: FORMATION
MECHANISMS, PROPERTIES, FUNCTIONS
INTRODUCTION
Kurochkina G. N., Pinsky D.L.
The adsorption of organic substances on an aluminosilicate matrix with high
energy is an essential problem of pedogenesis, primerely, of the formation of
highly dispersed mineraloorganic (MO) derivatives of the soil adsorbing complex
(SAC) [Gorb, Orl ]. Greenland believes that 50 to 80% of soil organic matter is
bound to clay mineral [Greenland]. The composition, degree of accumulation, and
migration of mineraloorganic derivatives determine the adsorbing capacity, the
type and fertility of soils and their resistance to anthropogenic impact [Malin Orl].
Many authors reveled that adsorbed MO form no continuous film on the surface of
a mineral; they are immobilized on a minor part of its surface, on so-called adsorption
sites [ Mal Theng]. The energy of interaction between these sites and organic
molecules affects the conformation of adsorbed molecules, the strength of surface
adsorption compounds, and finally, the degree of humus immobilization and its resistanse.
The aim of this work was to study the mechanism of adsorption interaction between
organic molecules and soil’s aluminosilicate in controlled conditions.
EXPERIMENTAL
The experimental subjects were synthetic gels with various contents of silica
and alumina, which ware used as analogs of soil’s aluminosilicate (Table 1).
Table 1. Basic physicochamical characteristics of the adsorbents
Sample SiO 2 /Al 2 O 3 S, m 2 /g V, cm 3 /g Surface
Charge
S
AS-1
AS-2
AS-5
A
100% SiO 2
4/1
2/1
1/2
100% Al 2 O 3
750
167
248
194
244
1.01
1.71
0.75
0.53
0.51
─
─
+
+
+
Note: S, silica gel; AS, aluminosilicate gel; A, alumina gel; s, the specific surface area as
measured with argon; and v, total pore volume.
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