Effect Of Inorganic Electrolytes Research Articles

Effect of electrolytes in aqueous solutions on oxygen transfer in gas–liquid bubble columns

The effects of inorganic electrolytes (NaCl, MgCl2, CaCl2) in aqueous solutions on oxygen transfer in a bubble column were studied. Electrolyte concentrations (c) below and above the critical concentrations for bubble coalescence (ctc), and six superficial gas velocities (vsg), were evaluated. The volumetric mass transfer (kLa) and the mass transfer (kL) coefficients were experimentally determined. It was found that the concentration of electrolytes reduced the kL, but the interfacial area (a) increased enough to result in a net increase of kLa. Using as independent variable a normalizing variable (cr=c/ctc), and maintaining fixed vsg, similar values of kLa were observed regardless the kind of electrolyte; the same happened for kL. This suggests that cr quantifies the structural effects that these solutes exert on mass transfer. Also, once cr=1 was reached, no significant variations were found in kLa and kL for constant vsg. It is concluded that the gradual inhibition of bubble coalescence (cr<1) governs the significant changes in hydrodynamics and mass transfer via the reduction of bubble size and the consequent increment of a and gas holdup (ɛg). Finally, regarding the effects of vsg on mass transfer, transition behaviors between those expected for isolated bubbles and bubble swarms were observed.

The study of quenching efficiency of three-phase foams formed in flotation of phosphate rock

The effect of inorganic electrolytes on the foaming and stabilizing activity of three-phase foams formed in flotation of phosphate rock was determined. It was shown that the effect of inorganic salts on the above properties of the foams depends on both the concentration of the salts and their nature.

Effect of inorganic electrolytes on the formation and the stability of water-in-oil (W/O) emulsions

The phase inversion temperature (PIT) is an inherent property of many water/nonionic surfactant/oil systems. It tends to form O/W emulsions when the PIT is high and vice versa. In the present paper, formation of W/O emulsions was studied in aqueous/polyoxyethylene 4 lauryl ether/paraffinic oil systems by simply homogenizing. Polyoxyethylene 4 lauryl ether is a common hydrophilic surfactant and is normally used to produce O/W emulsions. Inorganic electrolyte species and their concentrations were appropriately chosen to reduce the PIT for the formation of W/O emulsions. Furthermore, the effects of surfactant concentration and oil/water phase volume ratio on the PIT were investigated by measuring the conductivity variation. Stability of W/O emulsions was studied as a function of inorganic electrolyte concentration and storage time by bottle test, microscope observation, and viscosity measurement, which shows that the sedimentation and coalescence lead to the destabilization of W/O emulsions.

Effect of inorganic electrolytes and nonionogenic surfactants on the stability of soap stock emulsion

Modes in which the fat component of the soap stock emulsion is extracted under heating and introduction of various nonionogenic surfactants and electrolytes were studied. The compression isotherms of the soap stock and its mixtures with OP-7 and NaCl were examined by the Langmuir method, with 2D pressure recorded. Recommendations were developed for separation of the soap stock emulsion for recovery of the fat component from wastes produced in manufacture of vegetable oils.

Effect of inorganic electrolytes and aliphatic alcohols on the foaming capacity of sodium salts of carboxylic acids

Foaming and stabilizing capacities of sodium salts of carboxylic acids (lauric, myristic, palmitic) in the presence of aliphatic alcohols (hexanol, butanol) and inorganic electrolytes was studied.

Effect of surfactant micelles on the kinetics of oxidation of D‐fructose by cerium(IV) in sulfuric acid medium

AbstractKinetics of the oxidation of D‐fructose by cerium(IV) has been investigated both in the absence and presence of surfactants (cetyltrimethylammonium bromide, CTAB, and sodium dodecyl sulfate, SDS) in sulfuric acid medium. The reaction exhibits first‐order kinetics each in [cerium(IV)] and [D‐fructose] and inverse first order in [H2SO4]. The Arrhenius equation is found to be valid for the reaction between 30–50°C. A detailed mechanism with the associated reaction kinetics is presented and discussed. While SDS has no effect, CTAB increases the reaction rate with the same kinetic behavior in its presence. The catalytic role of CTAB micelles is discussed in terms of the pseudophase model proposed by Menger and Portnoy. The association constant Ks that equals to 286 mol−1 dm3 is found for the association of cerium(IV) with the positive head group of CTAB micelles. The effect of inorganic electrolytes (Na2SO4, NaNO3, NaCl) has also been studied and discussed. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 38: 18–25, 2006

Effects of inorganic electrolytes on zeta potentials of ceramic microfiltration membranes

The characterization of surface electrical properties of membrane materials is critical for understanding and predicting filtration performances of membranes. In this paper, electrical properties of alumina-based ceramic microfiltration membrane were studied. Zeta potential of the membranes itself is determined using electro-osmosis measurements in the presence of various electrolytes, including NaCl, NH 4Cl, CaCl 2, FeCl 2, AlCl 3, Na 2SO 4, Na 2S, Na 3PO 4, FeSO 4 and Al 2(SO 4) 3, which are commonly encountered in inorganic salt industry. The zeta potential is obtained over a wide range of pH values (2–12) at ionic strengths of 0.01 M. The zeta potential decreases with increase of ionic strength in the NaCl solution and isoelectric point (IEP) shows little dependence on the ionic strength indicating the absence of a specific adsorption of Cl − and Na + ions. The shifting of the IEP of the membrane to a higher pH value in FeCl 2, CaCl 2 and AlCl 3 solutions shows specific adsorption of the cations, and specific adsorption of the S 2−, S O 4 2 − , P O 4 3 − ions shifts the IEP to a lower pH value. The zeta potential in FeSO 4 and Al 2(SO 4) 3 solutions were very low, indicating a decrease of charge density on the membrane surface due to the complex co-adsorption of the cations and the anions on the membrane surface.

Surface-chemical study of an aqueous mixture of α-sulfolauric acid salts with cationics

The physicochemical properties of an aqueous mixture of α-sulfolauric acid (H 2LS) and its various salts, including sodium α-sulfolaurate (NaHLS), triethanolammonium α-sulfolaurate (TeAHLS) with a cationic surfactant, decyltrimethylammonium bromide (DeTAB), have been investigated. The surface activities of H 2LS and its salts were enhanced greatly in the mixed systems; e.g. for a 1:1 mixed solution, the cmc and γ cmc can be reduced from 1.4 × 10 −2 mol dm −3 and 45 mN m −1 to 5 × 10 −4 mol dm −3 and 24 mN m −1 respectively. The effect of inorganic electrolytes (NaBr and HBr) on the surface activity and the molecular interactions between the two surfactants in the mixed adsorption layer and micelles have been studied systematically. It was found that the phase separation concentrations (PSCs) of the mixed surfactant solutions are greater than the cmcs. For 1:1 NaHLS-DeTAB solution, PCS/cmc=3.2. It is also revealed that, unlike the common anionic-cationic mixture, e.g. C 10H 21SO 4Na-DeTAB, the mixed micellar solution is thermodynamically stable up to 3 × cmc.

Effect of inorganic electrolytes on the stability of allophane in aqueous solutions of anionic xanthan polysaccharide

The polymeric (a) weak-stabilization (PWST), (b) floccelation (PFL), and (c) stabilization (PST) of ailophane with the anionic xanthan (GX) polysaccharide (He and Horikawa 1996a, b: Soil Sci. Plant Nutr., 42, 603-612, 637-644) were investigated further with respect to the effect of 1-1, 2-1, and 1-2 electrolytes (MA). At pH 4.5, the PST was (i) high in 0.1 mM NaCl, MgCl2, ZnCl2, and PbCl2 solutions, whereas (ii) considerably low in 100 mM NaCl, 0.1 mM Na2SO4 and NaH2PO4 solutions, respectively. At pH 6.5 (i.e.p.), the flocculated ailophane showed (i) a very low PWST in 0.01 mM NaCl, MgCl2, and Na2SO4 solutions, and also (ii) a low PST in 0.01 mM MA except for NaH2PO4. In 0.01 mM PbCl2 and NaH2PO4 solutions, ailophane was well dispersed, respectively, and marked PFL and PST were observed with further addition of xanthan. The changes and decrease of PWST and PST were discussed in relation to the iocculation of ailophane due to the (a) effect of MA on the diffuse double layer of the particles, (b) specific adsorption of phosphate and lead ions on the surface, and (c) weakening of the repulsive force between anionic GX chains by MA.

Electrokinetic studies of monodisperse hematite particles: effects of inorganic electrolytes and amino acids

In order to examine the possibilities of using monodisperse (hydrous) oxide particles as model colloids, this paper studies the effect of simple inorganic electrolytes (1-1, 2-1 and 3-1) and of five different amino acids (alanine, glycine, lysine, threonine and glutamic acid) on the electrophoretic mobility μ e of monodisperse hematite ( α- Fe 2 O 3) particles. Maxima were found in the mobility-electrolyte concentration curves, unexpected for presumably indifferent electrolytes. Since no anion or cation adsorption seems to be present, the possible occurrence of high surface conductances is assumed to explain the results. Concerning the interactions of the amino acids with hematite particles, our data indicate that pH appears to be a determinant factor in the way such interactions occur. Measurements of the adsorption of amino acids glycine, lysine and glutamic acid onto hematite demonstrate that glycine adsorbs to a much lower extent than lysine or glutamic acid. The effect of pH on adsorption is very significant, a maximum in adsorption being found at a pH close to the isoelectric point of each amino acid. These results show that electrostatic interactions alone cannot explain completely the adsorption process: other effects, probably involving acid-base interactions must also be considered. In any case, our data show a reasonable agreement between electrophoretic mobility and adsorption experiments.

Einfluß anorganischer Elektrolyte auf anionischkationische Adsorptionsschichten/ Effect of Inorganic Electrolytes on Anionic-cationic Adsorption Films

The effect of inorganic electrolytes (NaCl, NaBr, NaI) on the simultaneous adsorption od decylpyridinium and octylsulfonate ions on the free surface of their aqueous solutions was studied. Surface excesses of each component were determined by using the Gibbs adsorption equation to the results of surface tension measurements. It was found that the presence of NaI in the solution has the greatest effect both on the adsorption of particular components and on the composition of anionic-cationic films adsorbed from equimolar solutions. This is related to high specific adsorbability of I - ions. The effect of NaCl or NaBr is much smaller, and the differences in the action of those electrolytes are observed only at higher concentrations.

The Effect of Inorganic Electrolytes on the Mixed Micelles Formation of Anioniccationic Surfactants

The Effect of Inorganic Electrolytes on the Mixed Micelles Formation of Anioniccationic Surfactants

Effects of inorganic electrolytes and of pH on micelle formation of amphoteric-anionic mixed surfactant systems

The effect of inorganic electrolytes on micelle formation of mixed amphoteric-anionic surfactant systems has been studied for various surface tensions, pH values, and relative viscosities. These systems are N α, N α-dimethyl- N ϵ-lauroyl lysine (DMLL)-sodium dodecyl sulfate (SDS), which include different inorganic electrolytes (NaCl, NaOH, or HCl). The critical micelle concentration (CMC) values of the surfactant, except that of DMLL, decrease with increasing concentration of NaCl. The ratio of decrease of CMC {[CMC 0 (CMC of salt-free system) — CMC s (CMC of added NaCl system)]/CMC 0} increases with increasing mole fraction of SDS in the mixed surfactant systems including NaCl. The pH value at every molar ratio decreases with increasing NaCl. The ratio of decrease of pH values { [a s , (activity of H + in added NaCl system) − a 0, (activity of H + in salt-free system) ] a s } for mixed surfactant systems is greater than that for each single surfactant system, and increases with increasing mole fraction of SDS in the mixed surfactant system including NaCl. The CMC values and relative viscosities increase monotonically with increasing mole fraction of DMLL in the mixed surfactant systems including NaOH. The CMC values of mixed surfactant systems including HCl are much smaller than those of systems including NaCl. Inorganic electrolytes appear to affect the magnitude of the hydrophilic-hydrophilic interaction between DMLL and SDS molecules in mixed micelles.

Effects of inorganic electrolytes upon emulsion polymerisation reactions. I. Effects upon kinetics of styrene emulsion homopolymerisation and of styrene‐acrylic acid emulsion copolymerisation

AbstractResults are given for the effects of two added inorganic electrolytes, potassium chloride and calcium chloride, upon the kinetics of the emulsion homopolymerisation of styrene and of the emulsion copolymerisation of styrene with a minor amount of acrylic acid, using sodium dodecylbenzenesulphonate as surfactant and potassium persulphate as initiator. Three reaction systems were investigated. Two were for the emulsion homopolymerisation of styrene, one reaction system using a relatively high level of surfactant and the other a relatively low level of surfactant. The third reaction system was for the emulsion copolymerisation of styrene and acrylic acid using an intermediate level of surfactant. The results show that the effects of added electrolytes can be varied and complex: they depend upon several factors such as the nature and amount of the added electrolyte, the level of surfactant, and the presence or absence of the acidic comonomer.

Effect of inorganic electrolytes on dissolution behavior of mixed anionic‐amphoteric surfactant systems

AbstractThe effects of some inorganic electrolytes on the dissolution behavior of anionic‐amphoteric mixed surfactant systems have been studied in terms of dissolution temperature of a hydrated solid surfactant; these systems are sodium dodecyl sulfate (SDS) ‐ Nα,Nα‐dimethyl‐Nɛ‐lauroyl lysine (DMLL), including different inorganic electrolytes (NaCl, NaSCN, or CaCl2). The dissolution temperatures of mixed surfactant systems are lower than those of pure surfactant solutions and become less than 0 C at a certain mole fraction of surfactants. As the concentration of NaCl increases, the dissolution temperatures of systems at a DMLL mole fraction lower than 0.4 increase, while those of systems at a ratio higher than 0.9 remain almost the same. With increasing concentration of NaSCN, the dissolution temperatures of systems at a DMLL mole fraction lower than 0.4 increase, while those of systems at a ratio higher than 0.9 decrease. For CaCl2 systems, there exists a maximum in the dissolution temperature at a certain composition, because addition compound formation between anionic and zwitterionic surfactants occurs due to the presence of calcium ions.

Thiols as Reducing Agents. 1. Polymerization of Acrylonitrile Initiated by the Peroxydisulfate-Thiomalic Acid Redox System

Abstract The aqueous polymerization of acrylonitrile (AN) initiated by the potassium persulfate-thiomalic acid (TMA) redox system has been studied at 35 ± 0.1°C in a nitrogen atmosphere. The rate of polymerization is governed by the expression, Rp = K[AN] [S2O8 2-]x[TMA]0.40, where x = 0.60 for lower monomer concentration md 0.75 for higher monomer concentration. The overall activation energy was found to be 7.3 kcal/mol in the investigated range of temperature. The deviations from normal kinetics are discussed, and a tentative mechanism of initiation is given. The effects of inorganic electrolytes on polymerization were also investigated.

Thermodynamics of binding of methyl orange and its homologs by poly(vinylpyrrolidone): The effect of inorganic electrolytes

AbstractThe extent of binding of methyl orange, ethyl orange, propyl orange, and butyl orange by poly(vinylpyrrolidone) has been measured in aqueous solutions of inorganic electrolytes such as NaCl, LiCl, NaSCN, and NaClO4 by an equilibrium dialysis method. The effect of the salts on the first binding constants and the thermodynamic functions which are accompanied by the dye—polymer association process was investigated relative to the corresponding values in the absence of such salts. It was found that in aqueous solutions of NaCl and LiCl the enthalpy change accompanying the binding is small and the largest contribution to the free energy of binding is from the positive entropy gain. For NaSCN and NaClO4, the values of ΔF° and ΔH° were both large and negative and the value of ΔS° was small and negative. Thus, the favorable free energy for the complex formation was due entirely to the negative enthalpy term. These characteristics of the thermodynamic quantities are discussed in terms of changes in structural properties of water in the vicinity of the binding entities and conformational changes of the polymer to which the dye is bound due to the added foreign electrolytes.

Effect of Inorganic Electrolytes on the Cloud Point of Polyoxyethylene Dodecyl Ether

Abstract The cloud points of polyoxyethylene dodecyl ether in the presence of different types of inorganic electrolytes have been determined. The cloud points can be expressed by the empirical equation: (C.P.)s⁄(C.P.)0=1+A\sqrtCs+BCs where (C.P.)0 and are the cloud Points with and without an electrolyte, respectively, Cs is the electrolyte concentration, and A and B are constants.

An improved microprocedure for the determination of heparin.

The microelectrophoresis method described by Jaques et al. (Can. J. Physiol. Pharmacol. 46, 351–360 (1968)) for identification and quantitation of microquantities of heparin was improved by using the differential effects of inorganic electrolytes on the solubility of quaternary ammonium – mucopolysaccharide complex. Samples were applied to agarose gel coated microscope slides for electrophoresis. The slides were then immersed in 0.1% cetylpyridinium chloride (CPC) in M NaCl at 35 °C with constant agitation for 5 h, washed thoroughly with 0.1% CPC, then stained with toluidine blue. As a result of this treatment, only heparin in concentrations of 0.25–2.0 μg produced optically dense spots on the slides for measurement. Heparin was identified by the combined information from electrophoretic migration, salt fractionation, and metachromatic activity.

The Viscosity of Aqueous Sodium Dodecyl Sulfate Solution and the Effect of Inorganic Electrolytes on It

The viscosity of aqueous sodium dodecyl sulfate solution and the effect of inorganic electrolytess were investigated. Linearity between the logarithm of the viscosity and concentration of sodium dodecyl sulfate until 25%, was observed. The viscosity of aqueous sodium dodecyl sulfate lowered when small amount of inorganic electrolytes were added, but increased when large amount of them were added. The viscosity was also affected by ionic valence of anion of inorganic electrolyte.