In this study, new composite materials of montmorillonite, biochar, or aerosil, containing metal–organic frameworks (MOF) were synthesized in situ. Overall, three different MOFs—CuBTC, UTSA-16, and UiO-66-BTEC—were used. Obtained adsorbents were characterized using powder X-ray diffraction, thermogravimetric analysis, nitrogen adsorption porosimetry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier transform infrared spectrophotometry. Additionally, the content of metallic and nonmetallic elements was determined to investigate the crystalline structure, surface morphology, thermal stability of the obtained MOF-composites, etc. Cyclic CO₂ adsorption analysis was performed using the thermogravimetric approach, modeling adsorption from flue gasses. In our study, the addition of aerosil to CuBTC (CuBTC-A-15) enhanced the sorbed CO₂ amount by 90.2% and the addition of biochar (CuBTC-BC-5) increased adsorbed the CO₂ amount by 75.5% in comparison to pristine CuBTC obtained in this study. Moreover, the addition of montmorillonite (CuBTC-Mt-15) increased the adsorbed amount of CO₂ by 27%. CuBTC-A-15 and CuBTC-BC-5 are considered to be the most perspective adsorbents, capturing 3.7 mmol/g CO₂ and showing good stability after 20 adsorption-desorption cycles.

Several 2-substituted 4-nitrobenzoic acid (NBA) derivatives such as 2-chloro-4-nitrobenzoic acid (2C4NBA), 2-methyl-4-nitrobenzoic acid (2CH34NBA) and 2-hydroxy-4-nitrobenzoic acid (2OH4NBA) were selected as model compounds because of their availability and chemically similar structures, in which the different group/atom (R) does not significantly affect the dominant intermolecular interactions – hydrogen bonds formed by the carboxylic group [1]. Quantum chemical calculations of lattice and intermolecular interaction energy were carried out to identify possible factors, which could be, used in prediction of the formation of solid solutions (SS) in binary systems of chemically similar molecules, in this case - various nitrobenzoic acid derivatives. Meanwhile, crystallization experiments were used to determine the experimental information about formation of solid solutions. The obtained crystalline phases were characterized by combined use of powder X-ray diffraction (XRPD) and differential scanning calorimetry/thermogravimetry (DSC/TG) [2].