Home – Home – Jornals – Chemistry for Sustainable Development 2021 number 1

To enhance oil recovery and limit water inflow in the fields with a low reservoir temperature (20-23 ºC), a new low-temperature nanostructured composition with two gel-forming components (polymer and inorganic) with improved rheological characteristics was developed at the Institute of Petroleum Chemistry SB RAS. Laboratory studies of gelation kinetics, rheological and filtration characteristics in the system polyvinyl alcohol (PVA) - boric acid - aluminium salt - carbamide - hexamethylene tetramine (HMTA) - polyol - water are presented. At a temperature of 20-23 ºC, this system forms coherently dispersed nanoscale structures of gel-in-gel type, with viscosity 2.4-6.8 times higher and elasticity 1.4-2.3 times higher than those of the gels with only one gel-forming component. The formation of gel directly in the reservoir leads to a selective water shutoff, a change in the direction of filtration flows, a decrease in water cut, and a limitation of breakthroughs of the injected working agent into production wells. Laboratory studies demonstrated the high efficiency of the composition for flow redistribution and additional displacement of oil from the channels with very high permeability. The composition is applicable to reduce water cut and to limit water inflow in cold wells, which allows us to recommend it for use on cold producing and injection wells with complicated geological structure of the formation, with highly permeable faults, cracks and washed channels, in particular, to limit water inflow and enhance oil recovery in the Permian-Carboniferous deposits of high-viscosity oil of the Usinsk field with the natural operating mode of development. Expected result: enhancement in the oil recovery factor (ORF), a decrease in the water cut of the product, and intensification of oil production.

The territories of discharge of ascending deep thermal waters are a unique object for studying the mineral composition of vegetation and soils under strong exposure to endogenous factors. The aim of this work was to determine the peculiarities of the accumulation of 25 chemical elements by Potentilla anserina L. in the impact zone of Kuchiger hydrotherms (Barguzin Depression, the Buryat Republic, Russia). The concentrations of Ca, K, Mg, P, S, and Zn in P. anserina plants did not vary significantly in the surveyed territory. In the zone of subaquatic discharge of ascending deep thermal waters, plants accumulated more Na, Sr, Li (near the discharge of high-temperature gryphons) and W, Mo (near the discharge of low-temperature gryphons). The maximum concentrations of Al, Mn, Ti, Cr, Ni, Co, La, and Y in the plants were found on the coastal diapir shaft with extremely high ascent activity of gas-hydrothermal mud fluids. Concentration of several elements in plant ash exceeded the clarke values for plants: Ca ( K_с = 2.0-3.6), Na ( K_с = 2.4-4.8), Sr ( K_с = 3.5-9.5), Ba ( K_с = 2.7-6.6), Li ( K_с = 6.0-17.0), Sc ( K_с = 6.0-21.0). The intensity of biological absorption was characterized by the biological absorption factor (BAF) . The highest coefficients were found for P and S (BAF = 22.4-69.2). The elements of strong accumulation are Ca, Na, K, Mg, Mn, Sr, Zn, Cu, Li, Ni, Mo (BAF = 1.5-10.5); the rest elements were very weakly accumulated by plants (BAF = 0.1-0.9). The change in the intensity of element accumulation by plants under different conditions leads to a violation of the ratios between Fe/Mn, Fe/Zn, Cu/Mo, Ca/Sr, Ca/Ba, K/Ba, Sr/Ba.

The physicochemical properties and structure of biosurfactants produced by oil destructor microorganisms represented by three strains - Rhodococcus 108, Acinetobacter 112, Acinetobacter 114 - are investigated. It is shown that all these microorganisms are capable of synthesizing both cell-bound and extracellular biosurfactants. The amount of free biosurfactants produced by Rhodococcus 108 strain is higher than the amount produced by the bacteria belonging to Acinetobacter genus. All the studied compounds contain carbohydrate and lipid components. According to the data of IR spectroscopy, the biosurfactant isolated from the Rhodococcus 108 strain is a compound bearing long-chain aliphatic hydrocarbons, ester bonds, carbonyl and OH groups, while lipopolysaccharide isolated from Acinetobacter 114 strain consists of a trisaccharide skeleton, to which the residues of fatty acids are added (С₁₀-С₂₂) via ester and amide bonds.

The process of calcium carbonate (calcite and vaterite modifications) crystallization from the solutions containing bile is investigated. It was found that calcite is formed in an uncontaminated environment and in the presence of 1 mass % bile, while an increase in bile concentration in the initial solution from 5 to 100 mass % promotes the crystallization of vaterite. It is shown that the mass of the solid phase increases in proportion to an increase in the bile concentration in the initial solution. The dissolution of the synthesized samples in 0.9 mass % NaCl and 0.05 mol/L EDTA was studied. It was revealed that the presence of bile components in the composition of solid samples reduces their dissolution rate.

The possibilities of new approaches to assessing the physiological adequacy of drinking water using biotesting methods are disclosed. Biotesting of waters, both depleted and enriched with potassium, sodium, calcium and magnesium, was carried out according to the indicators of acute water toxicity on freshwater fish Brachydanio rerio , genotoxicity on its blood cells, and chronic toxicity on Ceriodaphnia affinis . It was found that water samples with the optimal content of K⁺, Na⁺, Ca²⁺, Mg²⁺ do not exhibit toxicity, while in the samples in which the content of these elements is outside the range of optimal concentrations, chronic toxic and genotoxic effects are found.

The set and levels of phenolic compounds in water-ethanol extracts from the leaves of Spiraea betulifolia subsp. aemiliana (Schneid.) Hara (Rosaceae) were studied under natural conditions and after introduction into the environment of Novosibirsk (Russia). The samples were collected in two natural coenopopulations (Kunashir Island) and in the Introduction Division of CSBG SB RAS (Novosibirsk) in 2016-2019. Flavonoids and phenolcarboxylic acids were found in the extracts. Using high-performance liquid chromatography, we detected 19 phenolic compounds in the water-ethanol extracts from plant leaves of the natural populations and 26 in the introduced population. Thus, differences in high-performance liquid-chromatography profiles of phenolic compounds were found between the natural populations and the introduced population. Five new phenolic acids and one flavonol were discovered in the leaves of the introduced plant population. Additionally, the levels of some phenolic compounds in the leaves of S. betulifolia subsp. aemiliana changed as a result of the transfer from the wild to the new environment. Hyperoside (3.36-9.99 mg/g) is the major phenolic compound in the leaves of the natural populations, while quercetin (1.23-5.07 mg/g) is the major phenolic compound in the leaves of the introduced population. The differences in the leaf concentrations of quercetin and hyperoside between the natural and introduced populations were statistically significant ( P ≥ 0.05). Concentrations of taxifolin, isoquercitrin, rutin, avicularin, astragalin, kaempferol, and chlorogenic, p -coumaric, and cinnamic acids in the leaf extracts were found to be similar between the introduced and natural (Kunashir Island, Lake Kipyashcheye shore) populations. Across plant development phases, inhomogeneous distributions of individual phenolic compounds were revealed in the leaf extracts from the introduced S. betulifolia subsp. aemiliana .

Direct UV photolysis of the aqueous solutions of seven well-known pharmaceuticals was accomplished using a high-pressure mercury lamp. Within 30 min of irradiation, active substances of ranitidine and phthalylsulphathiazole were almost completely destructed, whereas paracetamol and novocaine were destroyed to a lesser extent. Stable organic products are not formed during the destruction of paracetamol, while the photolysis of sulphaguanidine leads to the formation of acetic acid, which was confirmed by means of ¹H NMR spectroscopy. It is concluded that UV photolysis may be used for initial wastewater treatment to remove the studied micropollutants.

The development of new two-phase aqueous systems based on surfactants for extraction requires the identification of patterns of delamination depending on the nature of the surfactant and salting-out agent. The phase equilibria in ternary aqueous delaminating systems containing a cationic surfactant - alkylbenzyldimethylammonium chloride (catamine AB) and an inorganic salting-out agent were studied. Catamine AB forms stratifying systems with chlorides (KCl, NaCl, NH₄Cl, LiCl, CaCl₂), sulphates (K₂SO₄, Na₂SO₄, (NH₄)₂SO₄), nitrates (KNO₃, NH₄NO₃, NaNO₃, Mg(NO₃)₂, LiNO₃, Al(NO₃)₃, Ca(NO₃)₂), as well as with Na₂CO₃, K₂CO₃, KHCO₃, NaBr, KSCN, NH₄F, (NH₄)₂HPO₄ and HNO₃. The influence of the nature of the salting-out agent on the process of system delamination is discussed. The best salting-out agents for catamine AB are nitrates, which have relatively low hydration energy in the series of studied anions. The phase diagram of the water - catamine AB - sodium chloride system was built up. The stratification region exists in a rather wide acidity range up to 2.4 mol/L H₂SO₄ (or HCl), and up to 2.8 mol/L NH₃ (or 4.7 mol/L NaOH). The phases remain transparent at all studied concentrations of inorganic acids and bases. The extraction ability of the water - catamine AB - sodium chloride system was evaluated. Thallium (III) is quantitatively recovered in the range of sulphuric acid concentrations from 0.5 to 2 mol/L. The range of recoverable metals may be expanded by using organic complexing agents. Quantitative extraction of lanthanum (100 μg) is observed in the system containing 2.2 g of surfactant, 2.0 g of the salting-out agent, 1 mL of 0.01 mol/L Arsenazo III solution with a total volume of 15 mL and pH ~8.

Thermodynamic modeling of hypergene processes in copper-nickel ore tailings was performed with the variations of temperature (3 and 20 ^oC) and water evaporation processes in the upper layers of tailings during summer months at low filtration coefficients. It is established that the major cations of pore solutions are magnesium, calcium, nickel and copper ions, while predominant anions are sulphate and hydrocarbonate ions. The main newly formed phases in the system are the minerals of smectite group, as well as goethite, carbonates, silica, chlorite and gypsum.

The spherical microstructures of bismuthyl (III) fumarate with the composition (BiO)₂С₄H₂O₄ were obtained using the standard method of precipitation from solutions at 23 and 60 ºС. The composition of the reaction product and its properties were studied using a complex of physicochemical methods. At 60 ^oC, the degree of bismuth precipitation in the product is not less than 99.8 % for the molar ratio of bismuth to fumarate ion equal to 1.5. According to IR and Raman spectroscopy data, both acidic residues of fumaric acid are deprotonated in the resulting compound, while the carboxylic groups have bidentate coordination to bismuthyl cation. The effect of temperature on the morphology of obtained compounds was studied by scanning electron microscopy and small-angle laser light scattering. According to scanning electron microscopy data, (BiO)₂С₄H₂O₄ obtained at 23 ºC is composed of spherical particles about 10-12 µm in size, consisting of thin nanoplates about 0.1 μm thick. The data of sedimentation analysis of the powder indicate a symmetric particle size distribution with the average particle size equal to 11.7 μm. With an increase in precipitation temperature to 60 ^oC, particle size decreases to 3-7 µm; an asymmetric function of particle size distribution is observed, and the average size of the aggregates is 30.9 µm. A possible mechanism for the formation of (BiO)₂С₄H₂O₄ spherical microstructures is described as a process combining Ostwald ripening and self-assembling. According to the data of thermal and XRD analyses, the product of thermal decomposition of bismuthyl fumarate at a temperature of 450 ºC is a monoclinic modification of Bi₂O₃.

The current level of traffic development is characterized by a continuous increase in the intensity of cargo transport vehicles and a rise of dynamic load on road coatings. Improvement of the quality of road bitumen through the search for novel technical and technological solutions remains an urgent problem for achieving high physical-mechanical characteristics of asphaltic concrete pavements and for ensuring their long lifetime. The effect of a cation-active adhesive additive on the range of plasticity of oxidized and non-oxidized bitumen is considered. The physical and mechanical properties of asphalt-concrete mix prepared on the basis of bitumen modified with the additive in different concentrations are investigated. A technology is developed for obtaining a modified bitumen binder involving the adhesive additive. On the basis of BND 60/90 grade bitumen, an experimental lot (40 t) of bitumen modified with the designed additive was manufactured, the test region of the roadway with the total area of 7900 m² was paved in Naberezhnye Chelny (Tatarstan, Russia), construction design supervision of the state of the test road region was performed.

A number of ceramic membrane reactors (CMR) of various designs and compositions for high-temperature hydrogen sulphide decomposition were studied. Two CMR types with the layered structure were used: the first type included catalyst layer, membrane support, and membrane layer, while the second one was composed of catalyst layer, membrane support, an intermediate layer, and membrane layer. It is demonstrated that the pore structure and the thickness of the membrane layer have a significant effect on permeability for H₂ and H₂S. Due to the high H₂/H₂S separation coefficient (more than 2.5), a significant improvement of the parameters of H₂S decomposition in CMR in comparison with the flow reactor with a granulated catalyst is observed. The H₂S conversion (with the formation of H₂) reaches 87 % at 900 ºC in the CMR of the optimal composition prepared using the optimal method.

The data on the content of 20 elements determined by means of X-ray fluorescence analysis using synchrotron radiation (SRXRF) in the leaves and stems of three Syringa vulgaris cultivars ‘Nadezhda’, ‘Olimpiada Kolesnikova’, ‘Pamyat o Kirove’ growing under the conditions of transport-caused and industrial pollution in Novosibirsk and under background conditions (reference). The concentrations of Mn, Fe, Co, Cr, Br, Rb, Nb in plants increased as a result of the technogenic impact, while the concentrations of Zn and Mo decreased (in comparison with the reference). The plants of ‘Nadezhda’ cultivar were distinguished by the increased content of microelements under urban conditions. As a consequence of environmental pollution, changes in the relations between physiologically essential chemical elements were observed in the leaves and stems of the plants. The smallest changes were detected in the Fe/Mn and Zn/Cu ratios in the plants of ‘Pamyat o Kirove’ cultivar. It was determined that the K/Rb ratio decreased under technogenic load in the plants of ‘Olimpiada Kolesnikova’ and ‘Pamyat o Kirove’ cultivars due to an increase in Rb content in the leaves and stems, while, quite contrary, this ratio increased in ‘Nadezhda’ cultivar with respect to the reference. On the basis of the calculated biogeochemical transformation coefficient, the most significant changes in the microelement composition are recorded for leaves and stems of the ‘Nadezhda’ cultivar, compared to others, which indicates its lower resistance to anthropogenic pollution in comparison with other cultivars. Common lilac plants of ‘Pamyat o Kirove’ cultivar were determined to tolerant to pollution under urban conditions.