Education of the republic of uzbekistan tashkent state technical university named after islam karimov

Results 

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Chemistry and chemical technology 
69 
Local residues of coal (powder) and fine particles were mixed with a solvent, asphaltene. 
Once the mixtures are well mixed, until they are thick, drawn out. Then they are prepared for 
granulation. After granulation, it is heated to 6000C. As a result of heating, additional gases are 
released. This is followed by the pyrolysis of activated carbon. The theoretical study of the 
sorption properties of the obtained activated carbon is based on the results of experiments carried 
out in a high-vacuum adsorption device. Figure 1 shows the adsorption isotherm of benzene on 
activated carbon obtained from local coal deposits at a temperature of 303 K. The adsorption 
isotherm initially shows ln (P / P0) = - 11. 
Fig
1. Isotherm of benzene vapor adsorption on an adsorbent obtained from local coal tailings at 
a temperature of 303 K.
This means that the adsorption of coal in the micropores is increased. Considering that 
the size of the benzene molecule is 0.6 nm, this indicates the presence of micropores in obtained 
adsorbent at values up to about 1 mol / benzene adsorption ln (P / P0) = -7. 
This means that benzene molecules are adsorbed in the inner pores of the coal. Then the 
adsorption reaches 4.5 mol / g, the pressure in the device is 119.38 mm / g set. equals. This value 
is equal to the saturated vapor pressure of benzene at 300 ° C, and the coal is saturated with 
benzene. 
The differential heat of adsorption of benzene vapor on a carbon adsorbent, obtained for 
research at a temperature of 303 K, is shown in Figure 2.Initially, the heat of adsorption of 
benzene is 105.05 kJ / mol at a = 0.055 mol / g at initial saturation, and a slight decrease in the 
heat of adsorption of subsequent benzene molecules is observed, at a = 0.52 mol / g, Qd = 85.16 
kJ / mol. One of the main reasons for the high heat of adsorption of benzene molecules at low 
saturations is explained by adsorption on micropores. Metal cations in the pores of the coal 
sample form. In the later stages of adsorption, the differential heat decreases. After a = 4.2 mol / 
g, the heat of adsorption is equal to the value of thermal condensation. Such a decrease in the 
differential heat of adsorption is absorbed by the micro- and mesopores of coal, and the 
adsorption temperatures decrease as they become saturated with benzene. The heat of adsorption 
of benzene vapor on coal obtained for research work is close to 33.8 kJ / mol, which corresponds 
to the heat of condensation, and 4.6 mol / g of benzene is adsorbed in total. 
a, 
m
ol
/g
 
ln (P/P
0
) 
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
-12
-10
-8
-6
-4
-2
0
ln(P/P°)
a
, мм
ол
/г

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