Kinetics and Bacterial Inactivation Induced by Peroxynitrite in Electric Discharges in Air

The mechanism of bacterial inactivation by electric discharges (non-thermal plasma) is examined on the basis of the action of the formed peroxynitrite and hydrogen peroxide on the external membrane of bacteria. A model accounts for the gas to liquid transfer of the active species which react with the bacterial wall at the liquid surface or /and in the bulk solution. Direct exposure to the glidarc discharge induces a pseudo zero order decay of the bacterial concentration, followed by a pseudo 1st order step for low concentrations. Post-discharge reactions develop after switching off the discharge according to a 1st order mechanism and show that active species drift in the solution. Additionally the bactericidal properties of pure water exposed to the discharge (i.e., ??Plasma Activated Water??) was evidenced even 24?h after performing the plasma treatment.     

气/液界面上十六烷基三甲基溴化铵水溶液的动态表面性质

用最大泡压法测定了不同温度下浓度低于cmc时十六烷基三甲基溴化铵水溶液的动态表面张力.发现当浓度低于0.10mol·m-3时动态吸附量ΓT遵s从由Henry吸附等温式导出的动态表面状态方程.在浓度位于0.10至0.80mol·m-3的较大范围内,Tt遵从从Langmuir等温式导出的动态表面状态方程.在吸附的后期十六烷基三甲基溴化铵分子在溶液表面上的吸附遵从混合动力学控制机理.从表观扩散系数计算出吸附为混合动力学控制机理时吸附能垒为6.7～7.1kJ·     

Degradation of Phenol in Aqueous Solutions by Gas–Liquid Gliding Arc Discharges

The efficiency of a gliding arc reactor designed with the aim to degrade aqueous phenol solutions is studied as a function of supply voltage, electrode gap distance, and gas–liquid flow properties. This efficiency, which steeply increases when increasing the supply voltage, can reach 96% when the minimum electrode distance is fixed at 3 mm. Experiments show that phenol degradation efficiency also depends on solution pH, Fe²⁺ addition, gas nature and gas flow rate. Furthermore, degradation pathways of phenol in aqueous solutions are proposed.     

Atmospheric Pressure Non-thermal Plasma for Air Purification: Ions and Ionic Reactions Induced by dc+ Corona Discharges in Air Contaminated with Acetone and Methanol

Plasma Chemistry and Plasma Processing - Atmospheric pressure mass spectrometry (APCI-MS) was used to investigate the positive ions in air containing acetone (A), methanol (M) and mixtures thereof...     

Thermodynamic Properties of Aqueous Solutions of Lithium Chloride

Vapor pressure of aqueous solutions of lithium chloride were measured by differential static method, in a concentration range of 12.9-44.2% weight and in the temperature range of 30-100°C. The experimental data were fitted to the Antoine type equation: log P = A( m ) + B( m )/ T + C( m )/ T 2 , where A, B, and C are constants which are concentration dependent. Enthalpies of solution were calculated by the Haltenberger method using experimental vapor pressure data and heat capacity data. The Duhring and enthalpy-concentration charts have been constructed. These charts may be useful in the performance studies of absorption heat pumps.     

Volumetric Properties of Aqueous Solutions of Cyclohexylsulfamic Acid

The mean apparent molar volume of cyclohexylsulfamic acid has been determined from the density data of aqueous solutions up to a molality of 0.540 mol⋅kg⁻¹ and at 293.15, 298.15, 303.15, 313.15, and 323.15 K. The mean apparent molar volume of the acid was divided into contributing ionic and molecular apparent molar volumes. The limiting apparent molar volume of the molecular acid amounts to (131.69± 0.02) cm³⋅mol⁻¹ and the limiting apparent molar expansibility to (0.130± 0.003) cm³⋅mol⁻¹⋅K⁻¹ at 298.15 K. From the limiting ionic and molecular apparent molar volumes the limiting volume change of ionization of cyclohexylsulfamic acid was calculated. A value of −7.76 cm³⋅mol⁻¹ was evaluated at 298.15 K. The temperature dependence of the volume change of ionization amounts to −(0.018± 0.009) cm³⋅mol⁻¹⋅K⁻¹. From the density data the coefficient of thermal expansion of the investigated solutions was calculated and from this the mean apparent molar expansibility of cyclohexylsulfamic acid was derived.     

New Physico-Chemical Properties of Extremely Diluted Aqueous Solutions

The extremely diluted solutions are anomalous solutions obtained through the iteration of two processes: a dilution 1:100 in mass and a succussion. The iteration is repeated until extreme dilutions are reached (less than 1·10^-5mol kg^-1) to the point that we may call the resulting solution an extremely diluted solution, namely the composition of the solution is identical to that of the solvent used (e.g. twice distilled water). We conducted thermodynamic and transport measurements of the solutions and of the interaction of those solutions with acids or bases. The purpose of this study is to obtain information about the influence of successive dilutions and succussions on the water structure of the solutions under study. We measured the heats of mixing of acid or basic solutions with such extremely diluted solutions, their electrical conductivity and pH, comparing with the analogous heats of mixing, electrical conductivity and pH of the solvent. We found some relevant exothermic excess heats of mixing, higher electrical conductivity and pH than those of the untreated solvent. The measurements show a good correlation between independent physico-chemical parameters. Care was taken to take into account the effect of chemical impurities deriving from the glass containers. Here we thus show that successive dilutions and succussions can permanently alter the physico-chemical properties of the water solvent. The nature of the phenomena here described still remains unexplained, nevertheless some significant experimental results were obtained. This revised version was published online in August 2006 with corrections to the Cover Date.     

Electrosurface Properties of Schungite III Particles in Aqueous Electrolyte Solutions

The kinetics of electrolyte extraction into water and the electrosurface properties (adsorption of potential-determining ions H⁺ and OH⁻ and ζ potential) of five fractions of schungite III (particle sizes of < 5, 50–100, 160–400, 400–1000, and 1600–2500 µm) are studied in aqueous NaCl, CaCl₂, and AlCl₃ solutions at different pH values. It is shown that, in water and NaCl and CaCl₂ solutions, the point of zero charge (PZC) of the particles with sizes of 50–100 and 160–400 µm is observed at pH 4.0 and is independent of the electrolyte concentration. The isoelectric point (IEP) for small (<5 µm) schungite III particles is observed at pH 2.8. The IEP position is independent of CaCl₂ concentration, but it shifts to pH 2.4 when NaCl concentration increases to 0.1 M. The disclosed differences in the PZC and IEP values may be caused by different compositions of particles of different fractions. In a 10⁻⁵ M AlCl₃ solution, schungite particles demonstrate three IEPs (pH 3.0, 4.5, and 7.4) due to different degrees of AlCl₃ hydrolysis at different pH values.__________Translated from Kolloidnyi Zhurnal, Vol. 67, No. 4, 2005, pp. 450–457.Original Russian Text Copyright © 2005 by Aleinikov, Lorentsson, Chernoberezhskii.     

Acid-Base Properties of 5-Hydroxy-1,3,6-trimethyluracil in Aqueous Solutions

Russian Journal of General Chemistry - 5-Hydroxy-1,3,6-trimethyluracil has been studied using 1H, 13C, and 15N NMR as well as UV spectroscopy. The constants and thermodynamic characteristics of its...     

Properties of Triglycine Sulfate Crystals Grown from Aqueous Solutions

A dielectric study of triglycine sulfate crystals was carried out and the phase transition temperatures were determined for samples grown at temperatures below 0°C. The influence exerted by a single-crystal silicon substrate treated by various methods on the shape of triglycine sulfate crystals was examined.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 1, 2005, pp. 45–51.Original Russian Text Copyright © 2005 by Stekhanova, Yatsenko, Milovidova, Sidorkin, Rogazinskaya.     

A New Gibbs Energy Model for Obtaining Thermophysical Properties of Aqueous Electrolyte Solutions

In this paper, a new Gibbs energy model is proposed to study the thermophysical properties of aqueous electrolyte solutions at various temperatures. The proposed model assumes that the electrolytes completely dissociate in solution. The model also has two temperature-independent adjustable parameters that were regressed using experimental values of the mean ionic activity coefficients (MIAC) for 87 electrolyte solutions at 298.15 K. Results from the proposed model for the MIAC were compared with those obtained from the E-Wilson, E-NRTL, Pitzer and the E-UNIQUAC models, and the adjustable model parameters were used directly to predict the osmotic coefficients at this temperature. The results showed that the proposed model can accurately correlate the MIAC and predict the osmotic coefficients of the aqueous electrolyte solutions better on the average than the other models studied in this work at 298.15 K. Also, the proposed model was examined to study the osmotic coefficient and vapor pressure for a number of aqueous electrolyte solutions at high temperatures. It should be stated that in order to calculate the osmotic coefficients for the electrolyte solutions, the regressed values of parameters obtained for the vapor pressure at high temperatures were used directly. The results obtained for the osmotic coefficients and vapor pressures of electrolyte solutions indicate that good agreement is attained between the experimental data and the results of the proposed model. In order to unequivocally compare the results, the same experimental data and same minimization procedure were used for all of the studied models.     

Electron Transport Properties of Ions in Aqueous Solutions of Sodium Selenite

Ion diffusion kinetics has been studied using the data of conductivity measurements for aqueous solutions of sodium selenite with different concentrations and at different temperatures. Molecular and ionic self-diffusion coefficients have been determined for infinitely dilute solutions in the temperature range 288 K-313 K. The limiting values of ion mobility and changes in the energies of translation of water molecules from ions’ hydration shell have been found. At elevated temperatures, ΔE _tr ⁰ increases for both ions in direct proportion to the crystallographic radius of the latter. Ion hydration numbers at 298 K have been calculated. The results of this study are interpreted in the light of Samoilov’s theory on positive and negative hydration of ions.Original Russian Text Copyright © 2004 by L. T. Vlaev and S. D. Genieva__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 870–876, September–October, 2004.     

Modifying Electrode Properties of Carbon-Fiber Materials by Electrolysis in Aqueous Solutions

The possibility of applying electrolysis in aqueous solution for the modification of electrode properties of carbon-fiber materials (CFM) is examined. It is shown that the cathodic and anodic polarization of CFM in solutions of acids and alkalis alters the state of the surface of fibers that constitute CFM, which is manifested in a change of the CFM electrode potential. The possibility of changing the CFM electroconductivity by an electrode treatment is demonstrated. This makes it possible to design electrodes with electroconductivity that varies over the electrode's thickness. The latter is of importance for both developing non-isoelectroconducting three-dimensional electrodes with a rigid matrix and comprehending operation principles of carbon-fiber electrodes. The obtained experimental data conform to the calculated dependences, specifically, profiles of electroconductivity and polarization over the electrode thickness are similar.     

Rheological and Adhesion Properties of Aqueous Solutions of Corn Dextrin

Rheological and adhesion properties of aqueous solutions of corn dextrin at widely varied concentrations, obtained at different mixing temperatures, were studied.     

Investigations of the Properties of l-Histidine in Aqueous NaCl Solutions at Different Temperatures

Density and viscosity experimental data for l-histidine in NaCl aqueous solutions were obtained at different salt and different amino acid concentrations in the range of temperatures between 293.15 and 323.15 K. The results have been correlated and analyzed in order to evaluate the influence of electrolyte concentration and temperature on the volumetric and viscometric properties of the solutions. The apparent molar volumes and the transfer volumes of l-histidine in aqueous NaCl solutions at different salt and amino acid molalities over entire temperature range were calculated from experimental density data. The viscosity experimental data have been analyzed with Jones–Dole equation and the Falkenhagen (A) and the Jones–Dole coefficient (B) have been calculated in order to evaluate the interactions occurring in the systems. The B viscosity coefficients were found to be positive for all conditions, showing a kosmotropic effect of solutes, indicating an alignment of zwitterions with ions/water dipoles. A comparison of standard partial molar volumes for some amino acids in water and NaCl aqueous solutions shows that they increase with molecular mass and complexity of the lateral side chain of the amino acid.     

Equilibrium and Transport Properties of Sodium n-Octyl Sulfonate Aqueous Solutions

Measurements of osmotic coefficients, mutual diffusion coefficients, and conductivity were performed on the binary system sodium n-octyl sulfonate (C₈SO₃Na)–water at 25°C both below and above the micellar composition range. The osmotic coefficient data were obtained through vapor-pressure osmometry, while the Taylor dispersion method was used to measure diffusion coefficients. The mass equilibrium model was applied to this self-aggregating system, taking into account the deviation of the activity coefficients from the Debye–Hückel limiting law by using the Guggenheim corrective terms for mixed electrolyte solutions. The expressions derived from the model fit the experimental osmotic and diffusion coefficient data well, when the same values of aggregation number, fraction of condensed counterions, and equilibrium constant are used. Osmotic coefficients were also used to determine the thermodynamic factor required to compute the solute mobility from diffusion data. Conductivity data were used to test two theoretical models, namely, the Onsager–Fuoss and the Mean Spherical Approximation theories. Both models have been found to yield unsatisfactory fits to our experimental data and some arbitrary terms had to be applied to the theoretical expressions to obtain good agreement between experiment and theory.     

Dielectric Properties and Structure of Aqueous Decaoxyethylene p-Isononylphenyl Ether Solutions

The static permittivity _s of aqueous decaoxyethylene p-isononylphenyl ether (NOP-10 grade) solutions is measured at surfactant concentrations of 1.14 and 4.97 wt % within 275–351 K temperature range; at concentrations of 9.96, 20, and 30 wt %, within 275–313 K range. Data on _s are analyzed, using the models of dilute disperse systems of oil–water type containing spherical particles, oblate and prolate spheroids. At 30, 20, and 9.96 wt % NOP-10 content, fragments of hexagonal mesophase are still retained in the isotropic phase near the interface, where there is a certain orientation of micelles acquiring the shape of prolate spheroids instead of cylindrical micelles. Upon heating up to 313 K, micelles are disoriented and their shape changes in prolate spheroid spherical micelle oblate spheroid sequence. With a further rise in water content, the fragments of lamellar mesophase appear in the isotropic phase at 4.97 and 1.14 wt % NOP-10 near the melting points of these solutions. They can exist with equal probability as the regions where either spherical micelles are located in the nodes of cubic lattice or oblate spheroidal micelles are distributed at random. As the temperature approaches the cloud point of dilute solutions, the randomly oriented oblate spheriodal micelles tend to acquire the disc-like shape.