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TEXTURAL ANALYSIS OF A TWO-DIMENSIONAL METAL-ORGANIC
FRAMEWORK CATENA[BIS (Μ2- (+) -TARTRATE) -DIAQUA-DI-
ZINC (II) TRIHYDRATE] OBTAINED FROM NITROGEN
ADSORPTION.
Abdullaev Ahrorjon Khabibjonovich
Institute of General and Inorganic Chemistry, Uzbekistan
Academy of Sciences, PhD student
Yakubov Yuldosh Yusupboevich
Institute of General and Inorganic Chemistry, Uzbekistan Academy of Sciences,
doctor of chemical sciences, professor
Ibragimov Aziz Bakhtiyarovich
Institute of General and Inorganic Chemistry, Uzbekistan Academy of Sciences,
director of institute, doctor of chemical sciences, professor
Institute of General and Inorganic Chemistry of the Academy of Sciences of the
Republic of Uzbekistan. 77-a Mirzo Ulugbek Street, Tashkent
ahrorabdullahabibjon@gmail.com
https://doi.org/10.5281/zenodo.14061792
Nitrogen adsorption of the compound was carried out. The sample was
synthesized using the solvothermal method. Its crystalline structure was
confirmed by X-ray diffraction (XRD), and its purity was determined to be 99.5%
through elemental analysis. The compound was used in the form of a crystalline
powder. To remove adsorbed gases and moisture, the sample was degassed at a
temperature of 120°C under a vacuum of <10−3 Torr for 12 hours. Prior to
adsorption measurements, the sample was purified with high-purity nitrogen.
The mass of the degassed sample used for adsorption measurements was 0.100
g. Nitrogen (N2) gas with a purity of 99.999% was used as the adsorbate. Before
use, the gas was dried using molecular sieves. The adsorption isotherm was
measured volumetrically using an Autosorb iQ gas sorption analyzer. Dead
volumes in the adsorbent were calibrated with helium.The adsorption isotherm
of nitrogen on catena[bis (μ2- (+) -tartrate) -diaqua-di-zinc (II) trihydrate] was
measured by the volumetric method using the Autosorb iQ gas sorption
analyzer. The pressure was measured with an accuracy of ±0.01%, and the
temperature was maintained at 77 K using liquid nitrogen [1].
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Table 1. Textural properties based on nitrogen adsorption of catena-
[bis (1,4-tartrate) cobalt (II) hydrate]n
S
BET,
m
2
/g
484,51
t-Plot Micropore Area, m
2
/g
112,45
t-Plot external surface area, m
2
/g
246,12
Сumulative surface area of mesopores (BJH), m
2
/g
309,41
t-Plot micropore volume, cm³/g
0,46
Mesopores cumulative volume, cm³/g
0,98
Maximum pore volume (HK), cm³/g
1,45
Аverage pore diameter (4V/A by BET), Å
120,3
Median pore width, Å
26,4
Average pore hydraulic radius (V/A by MP method),
Å
11,23
The time to reach equilibrium varied from 30 minutes to 2 hours,
depending on the pressure point. To ensure the accuracy of the results, the
isotherm measurement was repeated with the same sample, followed by a new
sample. The nitrogen adsorption-desorption isotherm for samples at 77 K is
illustrated in Figure 1 [2]. The isotherm belongs to type V according to IUPAC,
followed by a small amount of capillary condensation, forming an H3 hysteresis
loop (Figure 1).
The BET surface analysis was conducted using nitrogen at a temperature
of 77 K (P/P0 = 0.05 and 0.30), yielding a surface area of 484.51 m
2
/g and a
monolayer capacity of 1.08 mmol/g. The NLDFT method was applied to a
cylindrical pore model with a surface tension of 8.9 mN/m for liquid nitrogen
Figure 1. Nitrogen adsorption isotherm of catena[bis (μ2- (+) -tartrato) -diaqua-dirutheniu m
(II) trihydrate]
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(see Fig. 2). The pore size distribution revealed mesopores with an average
diameter of 2.64 nm and a total pore volume of 0.98 cm
3
/g (see Table 1). The
BET surface area, pore size distribution, and total pore volume indicate that the
adsorbent is predominantly mesoporous, which suggests its effectiveness for
applications in catalysis and gas storage.
References:
1.
Zhang W. et al. Regulation of porosity in MOFs: a review on tunable
scaffolds and related effects and advances in different applications //Journal of
Environmental Chemical Engineering. – 2022. – Т. 10. – №. 6. – С. 108836.
https://doi.org/10.1016/j.jece.2022.108836.
2.
Li T. T. et al. Regulation of the surface area and surface charge property of
MOFs by multivariate strategy: Synthesis, characterization, selective dye
adsorption and separation //Microporous and Mesoporous Materials. – 2018. –
Т. 272. – С. 101-108. https://doi.org/10.1016/j.micromeso.2018.06.023
Figure 2. Volume histogram of catena[bis (μ2- (+) -tartrate) -diaqua-di-ruthenium
(II) trihydrate].
