Every year the problem of water purification becomes more relevant. This is due to the continuous increase in the level of pollution of natural water sources, an increase in the population, and sharp climatic changes. The growth in demand for affordable and clean water is not always comparable to the supply that exists in the water treatment market. In addition, the amount of water pollution increases with the increase in production capacity, the purification of which cannot be fully handled by conventional processes. However, the application of novel nanomaterials will enhance the characteristics of water treatment processes which are one of the most important technological problems. In this review, we considered the application of carbon nanomaterials in membrane water purification. Carbon nanofibers, carbon nanotubes, graphite, graphene oxide, and activated carbon were analyzed as promising materials for membranes. The problems associated with the application of carbon nanomaterials in membrane processes and ways to solve them were discussed. Their efficiency, properties, and characteristics as a modifier for membranes were analyzed. The potential directions, opportunities and challenges for application of various carbon nanomaterials were suggested.

Highly porous expanded graphite was synthesized by the programmable heating technique using heating with a constant rate (20 °C/min) from room temperature to 400–700 °C. The samples obtained were analyzed by scanning electron microscopy, energy-dispersive spectroscopy, low-temperature nitrogen adsorption, X-ray photoelectron spectroscopy, Raman spectroscopy, thermogravimetry, and differential scanning calorimetry. A comparison between programmable heating and thermal shock as methods of producing expanded graphite showed efficiency of the first one at a temperature 400 °C, and the surface area reached 699 and 184 m²/g, respectively. The proposed technique made it possible to obtain a relatively higher yield of expanded graphite (78–90%) from intercalated graphite. The experiments showed the advantages of programmable heating in terms of its flexibility and the possibility to manage the textural properties, yield, disorder degree, and bulk density of expanded graphite.

In this work, carbonized materials produced from crushed and milled corncobs are presented. Different heat treatment regimes were investigated. It was found that at a temperature of 500 °C and a reaction time of 2 h, the material had the highest oxygen content with the most diverse surface group composition. In this case, in order to obtain material for the manufacture of supercapacitors preliminary grinding may be unnecessary due to the excessive number of groups on the surface. Based on obtained data, it is possible to propose the method of corncobs processing with the least economic costs. The resulting carbonized material is of interest for further research, in activation processes. The selection of activation temperature regime in case of physical activation (possible due to high potassium and calcium content in the samples) or temperature regime and reagents in case of chemical activation may allow conducting directed synthesis of activated carbon maximally suitable for application in supercapacitors and gas sensors.

In this work, the sensing properties of pure multi-walled carbon nanotubes and their mixtures used as an active material for chemoresistive gas sensors were studied. Initial materials were analyzed by scanning electron spectroscopy, Raman spectroscopy, and X-ray diffraction. The surface area was measured by low-temperature nitrogen adsorption. The films of initial multi-walled carbon nanotubes and their mixtures taken in mass ratios of 15/85, 30/70, 50/50 have been obtained by drop casting. Textolite with copper contacts on the edges of one side was used as a substrate. Gas sensing properties (the response and the recovery time) were investigated to 100-500 ppm NO2 at room temperature. The drop cast films of initials multi-walled carbon nanotubes and their mixtures as an active material showed high sensitivity and rapid recovery rate to nitrogen dioxide. It was found that mixtures of multi-walled carbon nanotubes have better sensing properties compared to pristine multi-walled carbon nanotubes.

In this work, composites based on polyester resin and multi-walled carbon nanotubes were prepared. The properties of the filler (dispersive composition, transmission electron microscopy images and energy dispersive x-ray spectroscopy of the nanotubes) are evaluated. The electrical properties of polyester composites filled with multi-walled carbon nanotubes were determined as a function of the AC field frequency. The percolation threshold was observed for composites containing 2 and 2.5 phr MWNTs. When the concentration of the filler was increased above the percolation threshold, the system ceased to behave as a dielectric. With increasing nanotubes content in the system an increase in conductivity was observed. The effect of the addition of carbon materials on the hardness of the composites was also evaluated. The slightest addition of nanotubes to the system increased the hardness value of the composites. For composites containing up to 2 phr of MWNTs the hardness of the system is higher than for unfilled polyester resin due to “cross-linking” of the filler to the polyester matrix. Above 2 phr MWNTs the hardness of the system decreases due to the filler content in the system becoming significant.