Composites of montmorillonite K10 (MMT K10) and ionic liquid (IL) containing a 1-butyl-3-methyl-imidazolium cation ([BMIm]⁺) and various anions, such as bis (trifluoromethylsulfonyl) imide ([NTf₂]⁻), trifluoromethanesulfonate ([OTf]⁻), and dicyanamide ([DCA]⁻) have been obtained in this work. A number of methods, such as dynamic light scattering (DLS), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermal gravimetry (TG), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, and nitrogen adsorption–desorption have been used to characterize clay, and to study the structure and thermal behaviour of the composites. It has been found that the MMT K10 powder has a narrow particle size distribution with a peak at 246 nm and a mesoporous structure (S_BET=195 m²/g). According to the FTIR spectra, MMT K10/IL interaction depends on the IL type. It has been identified that confined ionic liquid interacts with both clay and adsorbed water in accordance with the hydrophilicity and size of the anion, in the following order: [DCA]⁻ > [OTf]⁻ > [NTf₂]⁻. Characteristic temperatures of glass transition, crystallization, and melting have been determined for the ionic liquids under study and their MMT K10 composites. It has been revealed that when IL is adsorbed on the surface of clay, the phase transitions in IL change. The greatest changes are observed in the case of BMImNTf₂. By applying the method of thermogravimetric analysis, it is shown that composite formation is accompanied by a decrease in the IL thermal stability. Apparently, the highly developed surface of montmorillonite K10, obtained by acid treatment, plays a major role in the decrease in the IL’s thermal stability. The influence of the IL anion on the thermal and spectral characteristics of an MMT K10/IL composite was studied for the first time.

Sodium montmorillonite (Na-MMT) was synthesized as a result of two-stage processing of natural bentonite (Bent), and its particle-size distribution, structure and morphology were studied. It was found that the two-stage processing of the original clay resulted in a significant increase in the specific surface area (from 72 to 120 m² g⁻¹). The prepared Na-MMT powder was modified by two ionic liquids (ILs), namely, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMImNTf₂) and 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide (BMImNTf₂). Several methods, such as SEM, XRD, TG, DSC, FTIR spectroscopy were used to study the structure and thermal behavior of the produced ionogels. The effects of the IL cation on thermal characteristics of the Na-MMT/IL ionogels were studied. Using the DSC, characteristic temperatures of glass transition, crystallization and melting were determined for Na-MMT/IL composites. Taking into account the literature data and using the method of thermogravimetric analysis, it was shown that ionogel formation was accompanied by a decrease in the thermal stability of the IL.

The presence of pharmaceutical pollutants in the environment is one of the most pressing environmental problems. Adsorption from solution is an effective way to remove pharmaceuticals from liquid media, but the problem then is to separate the adsorbent from the liquids. The objective of the present study was to remove nitrofurazone from aqueous solutions using a bentonite/magnetite composite, prepared by co-precipitation of magnetite with bentonite, which could then be collected by magnetic separation. The bentonite/magnetite composite was characterized using diverse techniques, such as X-ray diffraction, scanning electron microscopy, low-temperature N₂ adsorption/desorption, laser diffraction, and magnetization measurements. The particle size of the composite material did not exceed 50 μm and the particle size distribution was mono-modal with a maximum at 3.2 μm. The strong hysteresis in the magnetization curve revealed that the bentonite/magnetite particles were ferromagnetic. Adsorption of nitrofurazone by the bentonite/magnetite composite from aqueous solutions was measured and the amount of nitrofurazone adsorbed was 3.2×10^–2 mmol/g. The adsorption kinetics of nitrofurazone to the bentonite/magnetite composite followed a pseudo-second-order kinetics equation. Upon adsorption, hydrogen bonds were formed between the amide groups of nitrofurazone and oxygen groups in bentonite.