C - Lublin

Electrolytic conductivity of preparations with Na-montmorillonite without
aluminum is (8.9-36.3 mS), with aluminum (8.1-15.7 mS), of preparations with
mica without aluminum (8.7-10.7 mS), with aluminum (8.8-39.4 mS), and of the
preparations with kaolinite without aluminum (9.6-18 mS), with aluminum (9-26.7
mS). An important influence of the pH value of the suspension was stated on the
value of electrolytic conductivity. The greatest correlation was found in the
organic-mineral preparations with kaolinite and with aluminum (r=0.93***) and in
the preparations with mica without aluminum (r=0.75 *** ). It was proved that the
greatest degree of reaction of the humic acids with Na-montmorillonite and with
mica took place at pH 5, and with kaolinite at pH 7 (in the above mentioned
combinations with aluminum). Aluminum clearly stimulated the increase in the
degree of complexity of humic acids with minerals.
Specific surface area is a very good parameter that characterizes the structure
of the organic-mineral adsorbent. Specific surface area was determined using the
initial part of the water vapour adsorption isotherm at 20°C within an adsorbate
relative pressure range of 0,P/P 0 , 0.35 in accordance with the Brunauer, Emmet and
Teller (BET) equation [Brunauer et al. 1938]. Water vapour adsorption were
determined at 20°C gravimetrically (by weight), using a vacuum dryer in a
temperature-controlled room according to Stawiński at al. (1999). The results of
the specific surface area were statistically analyzed, including analysis of variance
using the Statgraf software, and regression analysis using the Excel software. The
calculated relations were then described with a linear equation, logarithm and
power equation. The description of the relation analysis was made using the most
fitted function.
The variability of surface phenomena during the formation of synthetic
organic-mineral bindings is proved by different values of the specific surface area.
The specific surface area of the bindings with Na-montmorillonite without
aluminum ranges between 87 and 150.4 m 2 /g; with aluminum 145.6 to 152.8 m 2 /g;
for bindings with mica without aluminum 83.2 to 150.4 m 2 /g; with aluminum 145.6
to 152.8 m 2 /g; for bindings with kaolinite without aluminum 14.1 to 43 m 2 /g; with
aluminum 15.9 to 38.5 m 2 /g. A significant influence of the pH value of the
suspension on the size of the specific surface area was stated. The highest
correlation was observed in the bindings with kaolinite (r=0.93 ***). It was proven
that the addition of aluminum to the bindings with Na-montmorillonite
significantly influenced the growth of the specific surface area at pH 5, in bindings
with mica-at pH 7, and in bindings with kaolinite- at pH 3 and 4. At pH 3 there was
a significant decrease in that value and there was an increase at pH 4. The greatest
degree of reaction was stated in bindings with Na-montmorillonite (without Al) at
pH 5 , with mica (without Al) at pH 7, and with kaolinite at pH 5,6 and 7.
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