Keizo Ogino

Adsorption of phenol on surface-modified carbon black from its aqueous solution

Abstract The adsorption equilibria of phenol on the surface-modified and surface-unmodified electric carbon black in aqueous solutions have been studied. The carbon black used as an adsorbent was Electric Conductive carbon black (Lion Aquezo Co.). In order to clarify the relationship between the surface-chemical structure and the adsorption character of adsorbents, this carbon black was treated with nitric acid, hydrogen peroxide, dried air, or hydrogen gas. The adsorption characteristics were in good agreement with a Freundlich-type isotherm. The modification of the surfaces of the carbon black caused changes in the amounts of phenol adsorbed by them: H 2 treated > Unmodified > Dried air at 300°C > Dried air at 350°C > H 2 O 2 > 1N HNO 3 > 4N HNO 3 > 13.2N HNO 3 The adsorbed amount is closely related to the nature of the surface oxides on the modified carbon black.

Adsorption characteristics of organic compounds dissolved in water on surface-improved activated carbon fibres

Abstract The adsorption characteristics of low-molecular-weight organic compounds dissolved in water on hydrogenated activated carbon fibre (ACF) have been measured in terms of the amount adsorbed, the heat of immersion, and the heat of adsorption. The adsorption isotherms of the organics were found to conform to the Freundlich equation. The amounts of adsorbed polar compounds were increased by using ACF treated with hydrogen gas, which suggests that ACF has a relatively high hydrophobicity. The average electrostatic field strength increased as the number of functional groups on the ACF surface increased. The heats of adsorption decreased with increasing average electrostatic field strength. It was found that removing the polar functional groups attracting water molecules on the ACF surface resulted in an increase in the degree of adsorption of the low-molecular-weight organics from aqueous solution.

Solubilization of synthetic perfumes by nonionic surfactants

Abstract The solubilization of synthetic perfumes (eugenol, linalool, benzyl acetate, α-Ionone, α-hexylcinnamaldehyde, and d -limonene) by hexadecyl polyoxyethylene ethers (C 16 POE n , n = 10, 20, 30, and 40) has been studied in terms of cloud point, maximum additive concentration, solubilizing capacities, distribution coefficient, and micellar size. The greater the hydrophilic properties of synthetic perfumes, the more the cloud points of C 16 POE 10 solution are decreased. The maximum additive concentration and solubilizing power are increased with decreasing polyoxyethylene chain length, except for eugenol and linalool. The distribution coefficients of eugenol, linalool, and benzyl acetate between micelle and bulk phase are increased as the number of ethylene oxides in C 16 POE n decreases. The diameters of micelles containing solubilized synthetic perfumes are increased with increasing concentration of synthetic perfumes dissolved. Furthermore, for C 16 POE 10 solution, the diameters of micelles solubilizing eugenol and linalool are increased substantially in the vicinity of each maximum additive concentration.

Solution properties of mixed surfactant system. VI: The effect of oxyethylene groups in nonionic surfactant on surface tension of anionic-nonionic surfactant systems

The effect of oxyethylene groups in a nonionic surfactant on the surface tension of anionic-nonionic systems is described; these systems are sodium 3,6,9-trioxaicosanoate (ECL)-alkyl polyoxyethylene ethers (POEn, n = 10, 20, 30, and 40). The surface tension of each mixed surfactant solution decreases with increasing mole fraction of anionic surfactant. However, these surface tension vs mole fraction curves are shifted from specific curves to monotonous curve with increasing polyoxyethylene chain length in nonionic surfactant. Moreover, in the case of the mixed systems including a nonionic surfactant which has shorter polyoxyethylene chain length, the surface tension vs total concentration curve shows only one breakpoint. In the case of systems including the nonionic surfactant which has longer polyoxyethylene chain length, that curve shows two breakpoints in the vicinity of the CMC for ECL alone and that for POEn alone. This may be attributed to the fact that the mixed micelle is formed more easily by a nonionic surfactant including shorter polyoxyethylene chain length than by one having long. Then, in the mixed surfactant systems, there are two kinds of micelles coexisting (one rich in nonionic surfactant and the other rich in nonionic one).

New amphoteric surfactants derived from lysine. I. Preparation and properties of Nε-acyllysine derivatives-acyllysine derivatives

New amphoteric surfactants were prepared from Nε-acyllysine which was obtained by the thermal dehydration of a higher fatty acid salt of lysine and was not soluble in water. Nα,Nα-dimethyl-Nε-acyllysine was prepared by the catalytic reductive condensation of Nε-acyllysine ester with formaldehyde in good yield. Nα,Nα,Nα-trimethyl-Nε-acyllysine was obtained from the reaction of Nα,Nα-dimethyl-Nε-acyllysine ester with methyl iodide. Confirmation of the structure of these derivatives was obtained by spectrometric and spectroscopic analyses.The solubility of Nε-acyllysine was improved significantly by the introduction of Nα-methyl groups. Physicochemical and surface active properties of the derivatives were investigated in terms of isoelectric points, dissolution temperatures, surface tensions, critical micelle concentrations (cmc), foaming properties and wetting powers. Nα,Nα,Nα-trimethyl-Nε-acyllysine had lower dissolution temperatures than Nα,Nα-dimethyl-Nε-acyllysine. The latter showed lower surface tensions than the former at cmc. Nα,Nα-dimethyl-Nε-lauroyllysine was best in wetting power and foaming property.

Solution properties of mixed surfactant system (II): Electric properties of anionic-nonionic surfactants in aqueous solutions

Electric properties of mixed anionic-nonionic surfactant systems in aqueous solutions above the CMC have been studied in terms of pNa values, electrical conductivities, and dielectric constants; these systems are sodium 3, 6, 9-trioxaicosanoate (ECL) — alkyl polyoxyethylene ethers (CmPOE; m=12, 14, 16, and 18). The degree of ionic dissociation of mixed micelle increases with increasing the number of carbon atoms of the alkyl group in the nonionic surfactant. The electrical conductivity increases with increasing the alkyl chain length in the nonionic surfactant, in spite of the increase of the activation energy for conduction. The size of mixed micelles also increases with increasing alkyl chain length. This may be attributed to the fact that the mixed micelle is formed more easily by a nonionic surfactant including long alkyl chains than for one having shorter alkyl chains.

Interfacial action of natural surfactants in oil/water systems

This paper concerns the tendency of a few natural surfactants at the oil/water interface to induce spontaneous emulsification. N-paraffin (n-dodecane), liquid triglycerides (oleic safflower oil and corn oil), and liquid fatty acids (oleic acid and linoleic acid) were used as the oil phase and distilled water was used as the water phase. Natural surfactants such as cholesterol, lecithin, and oleic acid were applied to the systems as the oil-soluble additives. Lecithin was the most strongly effective in reducing the interfacial tension of the oil/water systems, and cholesterol was effective at the second strength. The oil/water interface of the systems containing the oil-soluble additives changed in various ways as observed by microscopy and the unaided eye. The most remarkable change was found in the system of glycerides containing cholesterol in contact with water, in which crystals of cholesterol were formed at the interface. 13 references.

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

Abstract 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 Nα,Nα-dimethyl-Nϵ-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 {[CMC0 (CMC of salt-free system) — CMCs (CMC of added NaCl system)]/CMC0} 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.

Dielectric constants and electrical conductivities of sodium dodecyl sulfate in aqueous solutions

Abstract Dielectric properties of sodium dodecyl sulfate in aqueous solution have been studied. The dielectric constant and ac electrical conductivity were measured in the frequency range 30 Hz to 6 MHz. At lower frequencies, with increasing concentrations of sodium dodecyl sulfate, dielectric properties were greatly affected by polarization on the surfaces of the electrode, the so-called space charge polarization. ac electrical conductivities were dependent on the concentration of sodium dodecyl sulfate at all frequencies. The activation energies of de electrical conduction were much larger in the molecular state than in the aggregation state. The radius of a spherical particle with an electric double layer could be calculated through the measurement of dielectric constant and de electrical conductivity.

Solubilization of azo oil dyes by sodium dodecyl sulfate

Abstract The solubilizations of some azo oil dyes by sodium dodecyl sulfate (SDS) have been studied in terms of the solubility and heat of solution against n -dodecane, the amount of solubilization, the solubilizing power, the dielectric constant, the electrical conductivity, and the surface tension. The order of hydrophobic characters of 5 dyes was determined from the solubility and heat of solution against n -dodecane. The amount of solubilization and solubilizing power increased with increasing hydrophobic characters of these dyes, except for 1-phenylazo-4-naphthylamine (4-NH 2 ). As regards the CMC, the smaller the hydrophobic characters of these dyes, the greater the reduction in CMC compared with that of SDS alone, except for 4-NH 2 . The oil dyes whose solubilization was large exhibited a large dielectric constant and a small electrical conductivity. In the case of oil dyes except for 4-NH 2 , the value of surface tension decreased with increasing amounts of dissolved oil dye until the limits of solubilization. The solubilization behavior was dependent on the kinds and the replacement positions of polar groups of oil dyes.