Aromatic and, in peculiar, polyaromatic hydrocarbons are one of the common class of anthropogenic pollutants. Processes of their degradation are of great interest from an ecological point of view. This article describes the current situation in the use of ultrasound as an instrument, accelerating such degradation.

This article succinctly outlines the key points of the emergence and development of methods for chemical modification of the surface of inorganic substrates. It is shown that the assumption of the presence of chemically active functional groups on such surfaces arose relatively recently, although the first experience of practical application was carried out in the middle of the 19th century. The main stages in the development of the chemistry of surface compounds are traced.

The review summarizes the results of experimental studies of physiological processes occurring in the organism of higher plants during their interaction with silver nanoparticles. According to the available data, silver nanoparticles can be internalized by plant roots and leaves and then transported throughout the plant organism via the apoplastic and symplastic pathways. When silver nanoparticles enter the plant’s body, they trigger a cascade of intracellular reactions. Depending on exposure conditions, silver nanoparticles can both have a positive effect, such as increased plant growth and activation of specific and nonspecific plant defense mechanisms, and a negative effect, such as plant development inhibition. The key factors determining the effect of silver nanoparticles on higher plants, such as the dosage and the route of exposure, as well as the physicochemical parameters, including the size of nanoparticles and the nature of the surface stabilizer were reviewed. Promising directions for further research were considered.

The aerobic oxidation of dibenzothiophene (DBT) was studied in hexadecane under ultrasonic treatment. Under these conditions, aldehydes can activate oxygen; however, the activation efficiency largely depends on the chemical nature of the aldehyde. The time dependence of the DBT oxidation in hexadecane was studied in the presence of valeraldehyde, caprinaldehyde, benzaldehyde, and anisaldehyde. After the treatment, the DBT concentration in hexadecane can decrease from 100 to 6 ppm. In the absence of ultrasonic treatment, the reaction does not proceed under these conditions.

В обзоре обобщены результаты работ по экспериментальному изучению физиологических процессов, происходящих в организме высших растений при их взаимодействии с высокодисперсным серебром. Показано, что наночастицы серебра способны к интернализации корнями и листьями растений, а затем к перемещению по всему растительному организму по апопластному и симпластическому путям. Попадая в организм растения, наночастицы серебра вызывают каскад внутриклеточных реакций. В зависимости от условий воздействия наночастиц, они могут приводить как к усилению роста растений и активизации в них процессов специфической и неспецифической защиты, так и к негативным последствиям, таким как угнетение развития. Показаны ключевые факторы, определяющие направленность и интенсивность воздействия наночастиц серебра на высшие растения, такие как доза и путь поступления наночастиц, а также их физико-химические параметры, включая размер наночастиц и природу поверхностного стабилизатора. Рассмотрены перспективные направления дальнейших исследований.

In this article, a method of depositing plasmonic particles on synthetic opal matrices was used for increasing the efficiency of laser-induced breakdown spectroscopy. The fundamental radiation, second and third harmonics of a picosecond neodymium laser were used to generate plasma. The dependences of the gain factor on the size of the laser spot, as well as on the concentration of silver particles, were obtained. The maximum signal amplification exceeding an order of magnitude was achieved at a wavelength of 1064 nm, corresponding to the localization of the plasmon resonance mode in the gap between closely spaced particles. Emission stability when using particles also increases at all laser wavelengths used. Conducted computer simulation confirmed the results of the experiment. High sensitivity of the method allows its use for monitoring even a small amount of impurity elements and their dynamics during the synthesis of photonic crystals, as well as the dynamics of the process of filling them with various materials during infiltration.

This study explores the interaction between 4-(2-pyridylazo)resorcinol (PAR) and lanthanum fluoride (LaF3) nanoparticles in an aqueous environment. The kinetics of PAR sorption were investigated, and the sorption isotherm of PAR at 20°C was obtained. Using the adsorption model of Frumkin–Fowler–Guggenheim, the magnitude of lateral interaction energy among PAR molecules adsorbed on the LaF3 surface and their sorption energy were calculated. Based on the sorption and spectral data, a structure for the grafted layer of PAR molecules on the surface of LaF3 nanoparticles is proposed.

A field trial to study the effect of preplant and foliar treatment of potatoes (lat. Solanum tuberosum) of Red Scarlett variety with dispersions of silver nanoparticles stabilized with polyhexamethylene biguanide hydrochloride was conducted. Silver nanoparticles were obtained by chemical reduction and characterized by UV–Vis spectrophotometry, transmission electron microscopy, and dynamic light scattering. The obtained nanoparticles were roughly spherical shape with the average diameter of 4.92 ± 2.66 nm. Preplant treatment of potato tubers and foliar treatment of potato plants were conducted with dispersions of silver nanoparticles with the concentrations of 5 and 0.2 mg/L, respectively. The treatment of potato with the dispersions resulted in an increase in values ​​of morphological indicators such as stem height, tops weight and leaf weight which in turn caused a significant increase in the yield (from 10.6 to 21.9% compared to the control variant) and commercial quality of the tubers. Notably, the maximum increase in the yield was obtained with the largest number of the treatments. In addition, silver dispersions showed a phytoprotective effect on potato plants which manifested in a decrease in damage to leaves by Phytophthora infestans from 30 to 7–8%. An explanation for the observed phytoprotective effect of silver nanoparticles based on the analysis of enzymatic activity in plant leaf tissues was proposed. The obtained results demonstrate high potential of application of drugs based on silver nanoparticles in horticulture as means of stimulating of growth and protection of plants.

In accordance with the abiogenic hypothesis of the origin of oil, deposits formed as a result of degassing of the Earth, in particular, due to the interaction of mantle methane and its polycondensation products with elemental sulfur, are thermodynamically open systems. In open systems, self-organization processes are realized and a progressive evolution of the catalyst of the basic reaction occurs, accompanied by an increase in its activity and accumulation in the system. The predominance of vanadium in the trace element composition of sour oils may be due to its catalytic activity in the basic reaction of the formation of C-S bonds.

The possibility of improving the procedure for preparing vanadyl phthalocyaninate in a mixture of normal aliphatic hydrocarbons by replacing phthalic anhydride in the starting reactants by phthalimide was evaluated. In the system with phthalimide, the vanadyl phthalocyaninate yield was thus increased by 21

Oil pollution is today one of the main factors of the technogenic impact on the environment. Emergency oil spills are the main source of the oil pollution. The causes, scales, and environmental consequences of emergency spills are considered. The advantages and drawbacks of methods for eliminating the spills of crude oil and petroleum products on the surface of water bodies are discussed. The features of the sorption method for oil collection from the water surface, which is the most widely used method, are described in detail. Requirements to petroleum sorbents are analyzed, and classes of the sorbents are described. Synthetic polymer sorbents have a set of advantages over other types of oil-absorbing materials. Fighting emergency oil spills should include the activity aimed at their prevention. This is particularly topical for Russia, which starts active operation of the Northern Sea Route and of shelf deposits of fossil fuels in seas of the Russian Arctic.

The article uses a magneto-sorption method for extracting asphaltenes from petroleum fractions using nanosized magnetite. Factors affecting the sorption separation of asphaltenes from toluene were evaluated using model systems prepared by dissolving asphaltenes isolated from su-perviscous oil from the Ashalchinskoye field (Tatarstan). It was found that the presence of polar compounds has the greatest effect on the sorption of asphaltenes from toluene solutions. Benzoic acid or isopropyl alcohol was used to evaluate the effect of acids and polar compounds. To study the effect of solution viscosity on asphaltene adsorption, model solutions of polystyrene in toluene with different viscosities were prepared by adding different amounts of polymer. Two types of sorbents were investigated: magnetite powder and suspensions of magnetite, modified with oleic acid, in toluene and n-pentane. The efficiency of using magnetite suspensions in comparison with its powder for sorption of asphaltenes is shown: for a suspension in toluene sorption increases 5 times, and in n-pentane, sorption increases 14 times. The influence of a magnetic field (0.5 T) on the increase in the sorption of asphaltenes from light oil feedstock was revealed: for a suspension in n-pentane, sorption increases from 220 +/- 25 to 313 +/- 38 g/g of adsorbent). The increase in sorption in the samples that passed through the magnetic installation is explained by the greater availability of asphaltenes due to the destruction of some of their clusters.

Calcium fluoride nanoparticles were prepared by double-jet precipitation. The influence of the synthesis conditions [solvent (water, alcohols, acetone, acetonitrile), temperature (20–95°С), presence of sodium citrate] on the morphology and size of the CaF 2 particles formed was studied. By varying the above factors, it is possible to prepare nonaggregated round or cubic nanoparticles with the mean size from 9 to 180 nm. The presence of sodium citrate in the reaction system leads to the chemical modification of CaF 2 and formation of a dense layer of citrate ions on its surface, which favors the formation of stable aqueous dispersions of CaF 2 . Assumptions concerning the structure of the layer of citrate complexes on the particle surface are made.

This review is devoted to the development, properties, and application of biosensors based on graphene nanomaterials. It is shown that such biosensors are characterized by their sensitivity, specificity of detection of analytes, high speed, and small size. Examples of the use of graphene biosensors for the detection of viruses, bacteria, markers of socially significant diseases, and various toxins are given.

Oxidation of dibenzothiophene with air oxygen is possible in the alkane—aldehyde system under ultrasonic influence. Capric and valeric aldehydes at 80 °C exhibited significant activity as oxygen activators, benzoic aldehyde was much less active, and paraform was inactive. No oxidation occurred in the absence of aldehyde and/or ultrasound.

This article provides a brief review of the current scientific literature on the structure, properties, and preparation of graphene nanomaterials (GNM) and their potential uses in pharmacology and biomedicine. The most important members of the graphene family are graphene itself and its oxide. GNM have been shown to have a set of unique physicochemical properties and have been studied intensely as substances for targeted drug delivery, gene transfection, hyperthermia, etc. GNM are regarded as potential nanomaterials for making implants and prostheses, and also as antibacterial substances. Problems facing researchers and requiring solution for successful introduction of GNM into practice are discussed.

Properties of graphene and its derivatives, allowing these materials to be used as effective sorbents, membranes, and sensitive elements of gas sensors, are considered. Data on procedures for preparing graphene and its oxide are presented. The literature survey demonstrates the possibility of developing selective sorbents based on graphene nanomaterials for many industrial processes including water desalination and recovery of radionuclides from process solutions. As judged from the results of laboratory experiments, membranes containing graphene and its oxides can be used in foreseeable future for nanofiltration, water treatment, and gas drying. Large-scale commercial use of graphene is yet restricted by the lack of economically acceptable procedures for preparing graphene nanomaterials of large linear size. For fabricating gas and biosensors, the millimeter size of receptor elements containing graphene and its derivatives is sufficient, and this size is achievable today.

The review briefly discusses the basic data on the preparation of porous silicas containing surface covalently bound organic ligands which specifically interact with analyte molecules. Single-stage (immobilization of the modifier) and two-stage (assembly on the surface) methods of their synthesis are consistently discussed. The data on the use of such sorbents as collectors of inorganic, organic, and biologically active substances are presented. Numerous examples of the use of such materials in sorption-instrumental analytical methods are demonstrated, and it is shown that this class of sorbents is the most preferable.