Chemical Composition Of Solution Research Articles

Features of interaction in the water-rock-CO2 system during the implementation of CCUS projects (on the example of chalk reservoirs in the Arctic sector of Western Siberia)

The paper considers approaches to the analysis of physicochemical interactions in the water-rock-carbon dioxide system, solved by mathematical modeling and aimed at analyzing the behavior of this system during CO burial in the Cretaceous aquifers of the Arctic sector of Western Siberia. The problem was solved using the HydroGeo software package, which makes it possible to analyze the change in the chemical composition of solutions, the forms of migration of the main components of groundwater, as well as mineral equilibria both at the time of carbon dioxide invasion and when the solution reaches equilibrium.

Physicochemical and thermodynamic properties of solutions of clary sage (Salvia sclarea L.) essential oil in ethanol-water system

Clary sage (Salvia sclarea L.) essential oil-ethanol-water system was investigated. The surface tension, density and refractive index of clary sage essential oil + ethanol (70%, 75%, 80%, 85%, 90%, and 95%) solutions were measured. The chemical composition of solutions (ratio 1:5, 1:6, and 1:7) was determined using GC/MS analysis. According the experimental results ternary phase diagrams were constructed. Comparative revue between experimental and calculated surface tension data was done. After analyses good correlation between two surface tension values was observed

Study on the chemical stability of the synthesized TiCx in Ti-Al-C system after immersion in the HF + H2O2 solution

The aim of this study is to investigate the phase stability of the prepared TiCx in Ti-Al-C system after immersion in the mixture of hydrofluoric acid (HF) and H2O2. The powders were immersed in the solution for different period times of 24, 48 and 96 h. The phase change of powders after different immersion times was studied by X-ray diffraction (XRD). The morphology evolution was detected by the field-emission scanning electron (FESEM). Moreover, atomic absorption spectroscopy (AAS) analysis was employed to study the changes in the chemical composition of solutions. The XRD results showed that by increasing the immersion time, gradually, the TiCx decomposed. It was also found that the selection oxidation aluminum occurred and the Al2O3 was the main final product of treatments. The FESEM images also confirmed the XRD results and after immersion of the powders into the solutions the rod-like and sheet-like morphology of the Al2O3 particles were obtained.

Elaboration and Investigation of Metallic Coating with Inclusion of Potassium Polytitanate

The possibility of receiving of compositional Ni-P coating modified by potassium polytitanate was analyzed. An aqueous solution to obtain the composite coatings on the basis of nickel-phosphorus alloy modified by K2О·nTiO2 onto steel details of the friction knots was developed. The complex oxide K2О·nTiO2 represents a layered material from the scaly form nanocrystals with 20-80 nm thick and "diameter" 280 nm. The velocity forming of the modified compositional Ni-P coating was investigated, and the optimal quantity of the introduced potassium polytitanate (8 g/l), as a modified compound into solution, was determined, too. The tribological characteristics and micro-hardness of the resulting coatings depending on the chemical composition of solution and surface state of the rider were investigated.

Effect of pH and Chemical Composition of Solution on Sorption and Retention of Cesium by Feldspar, Illite, and Zeolite as Cesium Sorbent From Landfill Leachate

Effect of pH and Chemical Composition of Solution on Sorption and Retention of Cesium by Feldspar, Illite, and Zeolite as Cesium Sorbent From Landfill Leachate

Mechanical Properties of Giant Plasma Membrane Vesicles

Giant unilamellar vesicles are a popular membrane model because of their accessibility to many experimental methods. While the ability to precisely control the composition of such membranes is advantageous for basic physicochemical characterization of lipid membranes and their interactions, artificially formed GUVs suffer from some limitations. Only membranes of low compositional complexity, low protein densities and random protein orientation in the bilayer can be obtained. In contrast, the plasma membrane of the living cell is highly complex in composition, crowded with proteins which have a defined orientation. As a missing link between these two extremes, chemically lysed plasma membrane vesicles have recently raised renewed interest. These vesicles, also called giant plasma membrane vesicles (GPMVs), have attracted attention because of their ability to exhibit optically resolvable liquid-liquid phase separation with micron-sized domains the formation of which is suppressed in the plasma membrane. In this work, we study the mechanical properties of GPMVs. We compare how various isolation conditions, such as chemical composition of solutions used to derive GPMVs, cell densities and cholesterol content, influence their bending rigidity. We also investigate how the local cellular environment modules the mechanical properties of extracted GPMVs. Furthermore, we measure the GPMV bending rigidity as a function of temperature and assess their phase state. Using micropipette aspiration we find a surprisingly large amount of hidden area which can be easily pulled out. We investigate the source and mechanism by which these area reservoirs appear. With these measurements, we hope to contribute to the understanding of the mechanical properties of the native plasma membrane. This work is part of the MaxSynBio consortium which is jointly funded by the Federal Ministry of Education and Research of Germany and the Max Planck Society.

LTCC MICROREACTORS APPLICATION IN A MICROFLUIDIC INTEGRATED SYSTEM FOR HYDROPHOBIC DRUG ENCAPSULATION IN POLYMERIC NANO/MICROPARTICLES

Nanotechnology develops methods and processes for Drug Delivery Systems (DDS) based on the fabrication of polymeric nano/microparticles with encapsulated drug that can be applied for maximize therapeutic activity and minimizes undesirable effects. However, these processes entail several conditions to operate efficiently. They present high sensibility to changes in temperature, flow rate, pressure, and chemical solution composition. An optimal configuration of these parameters is required to guarantee stable particle production. For these reasons, integration of technological devices like sensors, actuators, microfluidic devices and control systems is essential to increase particle production performance. The proposal of this work is to develop an integrated monitored and controlled system using LTCC (Low Temperature Co-Fired Ceramic) microreactors to generate polymeric nano/microparticles for encapsulation of hydrocortisone drug with PCL and Pluronic polymers. The microfluidic integrated system is developed through devices integration, system characterization and control loops configuration, using pressure sensors, syringe and microgear pumps, mixer and vortex LTCC microfluidic reactors, communication drivers, and data processing/control programs. Dynamic Light Scattering, Optical and Scanning Electron Microscopy were employed to measure particle size, polydispersity (PdI) distribution and particle morphology. Preliminary results showed nano/microparticles with encapsulated hydrocortisone drug having a mean diameter size of 528–816 nm and Polidispersity Index (PdI) < 0.5.

Atributos químicos da solução e do solo após aplicação de resíduo da extração de celulose

Este trabalho objetivou avaliar, em casa de vegetação e usando colunas de solo e ciclos de umedecimento, o efeito da aplicação de resíduos da extração de celulose sobre a composição química do solo e da solução extraída de dois Latossolos Vermelhos. O delineamento experimental utilizado foi inteiramente casualizado. Os tratamentos utilizados foram: T1 - Sem adição de calcário e resíduo (testemunha); T2 - 1,0 t ha-1 de calcário calcítico; T3 - 1,2 t ha-1 de dregs/grits; T4 - 0,8 t ha-1 de lama de cal; T5 - 2,4 t ha-1 de cinza; T6 - 1,8 t ha-1 de dregs/grits + lama de cal + cinza na proporção 1:3:6; T7 - 1,0 t ha-1 de dregs/grits + lama de cal na proporção 1:3. A avaliação da composição química da solução extraída de cada solo estudado, foi realizada durante quatro meses de incubação e análises químicas do solo, após este período. Os resultados foram analisados efetuando-se a análise de variância e o teste de Tukey para as comparações de média no nível de 0,05 de probabilidade. Dentre os tratamentos aplicados o 1,2 t ha-1 de dregs/grits pode não ser adequado para utilização no solo visto que transferiu maior concentração de Na+ para a solução do solo em relação ao recomendado pela literatura enquanto o tratamento 2,4 t ha-1 de cinza pode ser utilizado como fonte de K ao solo.

Chemical composition of soil solution under eucalyptus plantation in Southern Brazil

This study focuses on changes in the chemical composition of solutions during their transfer in the soil cultivated with hybrid of Eucalyptus urophylla x Eucalyptus globulus stand in southern Brazil. The chemical composition of soil solution was evaluated from January to December in 2010, when the plant was from 8.5 to 9.5 years-old. Ceramic lysimeters was installed in order to measure the chemical composition of the soil solution in two different depths (30 and 80 cm) with six repetitions. The lysimeters were connected to a vacuum pump, where in each four hours, during ten minutes, the solution was suctioned. The soil solutions were collected in glass bottles with 0.5 liters of capacity. Fortnightly the samples were collected and each replicate of soil solution was analyzed separately. The solutions were filtered (0.45 μm) and the nutrients concentrations were measured. The concentration of N – NO 3 - , K + , Ca 2+ , Mg 2+ , Na + , S – SO 4 2- and pH were variable during the year, but without significant difference (p > 0.05) in both depth (30 and 80 cm in depth). However, N - NH 4 + concentration of soil solution was high, for both depths, in the months November and December. The concentrations of soil solution N – NO 3 - , N - NH 4 + , K + and Mg 2+ are not different in the soil profile (30 and 80 cm depth). S – SO 4 2- (2.67 and 2.17 mg L -1 , respectively in 30 and 80 cm depth) and Ca 2+ (1.17 and 0.64 mg L -1 , respectively in 30 and 80 cm depth) decrease in soil profile (p < 0.05), whilst, Na + (2.10 and 2.60 mg L -1 , respectively in 30 and 80 cm depth) and pH (4.78 and 5.11, respectively in 30 and 80 cm depth) increase in soil profile (p < 0.05). Pearson’s correlation between cations and anions in the soil solution was significant (p < 0.01). In both depths, N – NO 3 - was directly correlated with Ca 2+ and Mg 2+ , whilst S – SO 4 2- was inversely correlated with Mg 2+ . This change in chemical composition of soil solution indicated different patterns of nutrients were taken up by roots.

Influence of solution volume on the dissolution rate of silicon dioxide in hydrofluoric acid.

Experimental data and modeling of the dissolution of various Si/SiO2 thermal coatings in different volumes of hydrofluoric acid (HF) are reported. The rates of SiO2 -film dissolution, measured by means of various electrochemical techniques, and alteration in HF activity depend on the thickness of the film coating. Despite the small volumes (0.6-1.2 mL) of the HF solution, an effect of SiO2 -coating thickness on the dissolution rate was detected. To explain alterations detected in HF activity after SiO2 dissolution, spectroscopic analyses (NMR and FTIR) of the chemical composition of the solutions were conducted. This is associated with a modification in the chemical composition of the HF solution, which results in either the formation of an oxidized species in solution or the precipitation of dissolution products. HF2 (-) accumulation in the HF solution, owing to SiO2 dissolution was identified as the source of the chemical alteration.

Experimental study of uranyl(VI) chloride complex formation in acidic LiCl aqueous solutions under hydrothermal conditions (T = 21 C?350 °C, Psat) using Raman spectroscopy

The chemistry of mineralizing fluids associated with several types of uranium deposits are chloride brines. To understand and model the formation of uranium deposits, knowledge of the behavior of U(VI) in chloride brines is necessary. The speciation of U(VI) in chloride aqueous solutions is studied here along the vapor saturation curve using Raman spectroscopy. Chemical composition of solutions is the following: UO 2 Cl 2 (0.01 M), HCl (0.1 M), and LiCl concentrations (0.3 up to 12 M). These solutions have been loaded in silica glass capillary and heated from 21 °C up to 350 °C at saturated vapor pressure. Raman spectra show an evolution of the band profile of the symmetric stretching (ν 1 ) of UO 2 2+ with increasing temperature and chlorinity. This band profile evolution results from the variation of the contribution of each chloride complex UO 2 Cl n 2−n ( n = 0 to 5) and an unidentified complex at 841 cm −1 which could be a polyuranyl chloride complex. U(VI) is transported by a mixture of uranyl chloride complexes in acidic brines conditions. From fitted Raman spectra, equilibrium constants K n + 1 (UO 2 Cl n 2−n (aq) + Cl − (aq) = UO 2 Cl n+1 1−n (aq) ) have been calculated as a function of temperature and chlorinity. Comparison of the value of the stepwise equilibrium constant ( β 0 ) at room temperature for the first chloride complex ( n = 1) agrees with literature data. The stability of the presumed polyuranyl complex (ν 1 ≈ 841 cm −1 ) has to be unraveled for lower uranyl concentration.

Role of Ionic Transport in the Electrochemical Activation of Water Solutions

The change in electrical conductivity of water solutions during electrochemical activation in a stationary diaphragm cell was studied. It is shown that the chemical composition of solutions and processing time have an important influence on the activation process. Method of operational control of the electrochemical activation process based on an analysis of the value of the current passing through the cell at a constant voltage on the electrodes was proposed.

Interaction of some essential amino acids with synthesized poorly crystalline hydroxyapatite

This study focused on the release of two essential amino acids, l-lysine and dl-leucine, previously adsorbed onto poorly crystalline hydroxyapatite of Ca/P=1.59, synthesis by precipitation methods. The composition of the calcium-deficient hydroxyapatite (CDHA) is chemically and structurally similar to the bone mineral. Their surface reactivity is indeed linked to the existence of hydrated surface particles (HPO42- and Ca2+). The adsorption kinetics is very fast while the release kinetics is relatively slow. The adsorption rate reached approximately 70%, but the release rate did not exceed 12%. The chemical composition of solution has an influence on the release processes. The presence of phosphate ions favored the release of amino acids, while the calcium ions inhibited it. Also, the release process is slightly influenced by Ra (ml/mg) ratio and incubation temperature of the medium. The charged –COO− and NH3+ of amino acids are the strongest groups that interact with the surface of hydroxyapatite, the adsorption is mainly due to the electrostatic interaction between the groups –COO− of amino acids and calcium Ca2+ ions of the hydroxyapatite. dl-Leucine (non-polar) and l-Lysine (polar–basic) interact with the hydroxyapatite surface in the zwitterionic and cationic forms, respectively. The study of interactions between amino acids and hydroxyapatite is carried out in vitro by using UV–vis and infrared spectroscopy IR techniques.

Selenite Adsorption and Desorption in Selected South Dakota Soils as a Function of pH and Other Oxyanions

Changes in soil pH and chemical composition of solutions in vadose zone strongly affect selenite (SeO32−) adsorption and desorption properties. In this study, batch experiments were carried out to evaluate the properties of SeO32− adsorption and desorption in four South Dakota soils as a function of pH and the presence of competitive oxyanions. Selenite adsorption capacity of the soils was strongly dependent on soil pH and decreased with increasing pH between 5 and 9. Selenite adsorption capacity increased with increasing specific surface area of the soils, and Langmuir isotherm was described as an SeO32− adsorption behavior. The presence of phosphate (HPO42−) in solution significantly decreased the partition coefficient values and adsorption maximum from Langmuir isotherm on all tested soils. Although HPO42− addition affected SeO32− adsorption in all soils, the effect had depended on the pool size of SeO32− adsorption site. The competitive effect between SeO32− and HPO42− was less apparent in soils with a high adsorption capacity, and the competitive effect was more apparent in low-adsorbing capacity soils. The amount of SeO32− adsorbed per unit area was lower in the presence of HPO42− in solution, but the depression by HPO42− addition was greater in low-adsorbing capacity soils compared with high-adsorbing capacity soils because of the much fewer adsorption sites. Contrary to HPO42−, sulfate in solution had little effect on SeO32− adsorption on all tested soils, which indicates that specific adsorption plays a major role in the adsorption of SeO32−. The desorption of adsorbed SeO32− was found to be dependent on the amount of SeO32− initially adsorbed on soils and HPO42− in solution. Significantly more SeO32− desorbed when HPO42− was in solution compared with sulfate.

Chemical composition of solutions in macro- and micropores in the upper horizons of soils in the Central Forest State Biosphere Reserve

The average concentrations of Al, Si, Fe, Mn, Pb, Ni, V, Ba, and other elements were 1.5–3.5 times lower (in some cases, up to 60 times) in the macropores than in the micropores. The regularities found agreed with the rules of selective absorption of ions and their capability for the formation of complexes with the components of the soil solids. The behavior of Fe and Mn can be explained by the differences in the redox conditions in the pores of different sizes. The degree of the relationships between the soil solution and the solid phase of the matrix in the macro- and micropores differed by several orders of magnitude (within a pF range up to 4). This fact determined the different mobilization of the elements in the solutions of the macro- and micropores. The reserves of the elements were proportional not only to their concentrations but also to the amount of solution in the appropriate pores.

Sorption of radionuclides from solutions with composite materials based on Mikoton natural biopolymer

Composite sorbents based on Mikoton natural biopolymer, selective to 90Sr, were prepared, and features of 90Sr sorption with these sorbents were discussed. The inorganic compound used as modifier is deposited on the surface of fibers of Mikoton biopolymer in the form of single crystals and polycrystals. Certain physicochemical parameters of the sorption were determined: static exchange capacity, constants of sorption equilibrium, etc. Deposition of BaSO4 on the surface of biopolymer fibers increases the sorption capacity toward 90Sr in solutions containing sulfate ions, and deposition of MnO2 enhances the sorption of 90Sr from solutions with high concentrations of salts. The influence of the chemical composition and pH of solution was studied in detail. The calculated low value of ΔG0 of radionuclide sorption is attributed to the simultaneous occurrence of several parallel processes in the system, some of which are energy-consuming. The Mikoton-Cs sorbent {composite of Mikoton biopolymer with K2Cu[Fe(CN)6]} appeared to be only weakly sensitive to variation of the chemical composition of the solution in a wide range of salt concentrations.

Recovery of 137Cs and 90Sr from wastewater by sorption on finely dispersed minerals under static conditions

The natural minerals clinoptilolite and tripoli were used for sorption treatment of liquid radioactive waste (LRW) to remove 137Cs and 90Sr. The efficiency of sorption recovery of these radionuclides with finely dispersed mineral sorbents under static conditions was studied in relation to the sorption time, pH, size of mineral granules, sorbent amount, salt content and chemical composition of solutions, and number of successive sorption steps. The distribution coefficient of radionuclides between the sorbent and aqueous phase and the sorption capacity of sorbents for radionuclides were determined. It was found that treatment of real salt-containing LRW from the Leipunskii Institute of Energy Physics, State Scientific Center of the Russian Federation, with the natural sorbents decreased their activity by 2–3 orders of magnitude owing to recovery of 137Cs and 90Sr.

Synthesis of Hydroxyapatite During Glassy Matrix Dissolution: Influence of their Chemical Composition

Experimental alteration of synthetic Ca–Si–P glasses was performed in pure water at 90°C from 1 to 56 days. The secondary phases formed during this alteration were analyzed by powder X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. Changes in the chemical composition of solutions during the reaction were also measured. The results revealed the growth of hydroxyapatite on the glass surfaces, especially for the most calcic of them. Moreover, the stability of the glasses during an alteration process directly depended on their chemical compositions; the more siliceous glasses appeared to be the less alterable matrices. Thus, the development of hydroxyapatite crystals may be experimentally controlled by the chemistry of the starting glassy materials.

Experimental studies of low-T oxygen isotope fractionation between carbonate minerals and water

Oxygen isotope fractionation factors between calcium carbonates and water have been applied to ancient marine geochemistry principally for the purpose of geothermometry. The problem was encountered, however, with respect to the direction and magnitude of O isotope fractionation between calcite and aragonite at thermodynamic equilibrium. This study presents a series of synthesis experiments at 0–70 C to resolve these intriguing issues. The experiments were designed with oneand two-step approaches, respectively, corresponding to the two complex anions of dissolved carbonate prior to aragonite precipitation. Witherite and metastable aragonite were directly synthesized by the direct precipitation and the overgrowth techniques, respectively. The twostep experiments delivered equilibrium fractionations between the precipitated carbonate and water, whereas one-step experiments did not. Significant difference was observed in experiment-derived calcite–aragonite fractionations at above 25 C; the two-step experiments at different periods from 20 to 60 days demonstrate that the dissolved [CO3] 2 and H2O have achieved O isotope equilibrium prior to the aragonite precipitation. Thus this difference cannot be ascribed to rapid (disequilibrium) precipitation of aragonite from either [CO3] 2 or [HCO3] dominant solutions. The experimental results show that the equilibrium fractionations derived from the two-step experiments are independent of the effects of high solution pH, the low O/O ratio of [CO3] 2 and rapid precipitation. Our experiments suggest negligible effect of Mg concentrations on the O isotope fractionations within the analytical error, indicating that no salt effect of Mg cation occurred under the experimental conditions. The O isotope composition of precipitated aragonite does not depend on the concentration of dissolved carbonate species in aqueous solutions provided that the O isotope equilibrium is really achieved thermodynamically between dissolved carbonate and water. Although the effects of the chemical composition of solutions may occur in synthesis experiments on the carbonate–water fractionations, enough attention must be paid to the kinetic mechanism of O isotope exchange and equilibrium in carbonate-water systems. It is of critical importance in judging the achievement of O isotope equilibrium between the dissolved carbonate complex anions and water prior to the precipitation of either aragonite or calcite. According to the currently available observations, it appears that the direction of O isotope fractionation between calcite and aragonite is positive rather than negative at thermodynamic equilibrium.

The Salty and Burning Taste of Capsaicin

The tongue is a kind of funny organ. From a physiological point of view, you can place solutions on the tongue that will be toxic to most any cell, and the tongue will give information, in a hopefully reversible manner, about the solution's chemical composition and whether it should be ingested.