Kazuo Kondo

Role of surfactants in the behavior of emulsion liquid membranes. Development of new surfactants

Abstract Surfactants play an important role in the emulsion liquid membrane (henceforth ELM) process. However, only two commercial surfactants have been used so far, Span 80 and polyamine. Relatively little attention has been spent in searching for other suitable surfactants. In order to develop new surfactants for the ELM process, in this study a series of derivatives of glutamic acid dialkyl esters and dialkyl-type quaternary ammonium salts were synthesized. Copper extraction by ELM was carried out in a stirred cell using these surfactants. It was found that glutamic acid dioleyl ester was a more suitable surfactant for the ELM process than Span 80 and polyamine as regards break-up, swelling and demulsification of the W/O emulsion, and enrichment of copper.

Effect of new surfactants on zinc extraction with liquid surfactant membranes

Abstract Using newly synthesized surfactants, extraction of zinc ion with liquid surfactant membranes (LSMs) containing 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester ( PC-88A) as a carrier was carried out in a stirred cell. The adsorption properties of surfactants were clarified and the effects of new surfactants on zinc extraction by LSMs were studied. New surfactants having two oleyl chains form stable emulsions in an even lower concentration range than the commercial surfactants. The extraction rate of zinc by LSMs was explained by an interfacial reaction model between the carrier and zinc ion taking into account the adsorption of a surfactant at the interface. Additionally, it is found that the new cationic surfactants appeared to accelerate the extraction rate due to an electrostatic interaction with the carrier.

EXTRACTION MECHANISM OF PALLADIUM WITH DIDODECYLMONOTHIOPHOSPHORIC ACID IN HEPTANE DILUENT

ABSTRACT Kinetic study of the extraction of palladium(D) with didodecylmonothiophosphoric acid in n-heptane diluent was carried out using a stirred transfer cell to clarify the extraction mechanism. The effect of surfactants on the kinetics of palladium extraction was also investigated, to elucidate the role of surfactants used in liquid surfactant membranes. Moreover, the interfacial tension between the organic and aqueous phases was measured to elucidate the adsorption equilibrium of the surfactants. It was found that the interfacial activity of each surfactant is higher than that of the extractant. In the kinetic study of palladium extraction, the experimental results of the extraction rate was analyzed by the interfacial reaction model, taking into account of the adsorption of the surfactant and extractant. The rate-determining step of palladium extraction was the complex formation between four chloro-palladium complexes and the extractant at the interface, and the extraction rate constants of each pa...

Extraction of Copper With Liquid Surfactant Membranes

Abstract Studies of the extraction of copper with liquid surfactant membranes containing a mobile carrier were conducted in a stirred transfer cell. It was found that: (1) the resistance of the diffusion step in liquid surfactant membranes is negligible compared with that of the diffusion step accompanied with chelating complex formation in the outer aqueous solution, (2) the initial rate of copper extraction varied inversely as the 0.5 power of hydrogen-ion concentration in the low-pH range, but in the high-pH range was not affected by hydrogen-ion concentration, (3) the initial rate of copper extraction was proportional to the concentration of benzoylacetone, which is the mobile carrier in the membranes, in the low-pH range, but the rate was scarcely affected by benzoylacetone concentration in the high pH and benzoylacetone concentration ranges. These results are consistent with a model of liquid surfactant membranes which is presented.

Equilibrium of solvent extraction of lanthanide ions with didodecylphosphoric acid

ABSTRACT Measurement of the extraction equilibrium of europium by didodecylphosphoric acid dissolved in toluene diluent vas carried out at 303 K. From vapor-phase osmometry, it was found that the extractant (HR) is apt to diaerize in toluene diluent. It vas clarified that the lanthanide ion (Ln3+) is extracted according to the following equation. The extraction equilibrium constant of the metal vas obtained. The extraction equilibria of three lanthanide ions, that is, samarium, europium and gadolinium by the extractant from mixed solution of the metals were also measured. The extraction equilibrium constants of respective metals were obtained. The separation factor between samarium and europium vas found to be improved compared vith the extractions by 2-ethyIhexylphosphonic acid mono-2-ethylhexyl ester and di (2-ethylheiyl)phosphoric acid.

KINETICS OF COPPER EXTRACTION WITH KELEX 100 USING A HOLLOW FIBER MEMBRANE EXTRACTOR

Abstract ABSTRACT The kinetics of copper extraction with Kelex 100 and stripping of copper chelate complex with sulfuric acid were examined in a tubular extractor consisting of a hollow fiber, along with the measurements of the distribution equilibria of Kelex 100 and cupric ion. The experimental results of the extraction and the stripping were analyzed by a diffusion model with interfacial reaction of which the rate determining step is the interfacial reaction between the adsorbed Kelex 100 (HR) and the adsorbed complex (CuR+).

SOLVENT EXTRACTION OF ZINC FROM CHLORIDE MEDIA WITH SECONDARY LONG-CHAIN ALKYLAMINE

ABSTRACT In the solvent extraction of zinc from chloride media with a secondary long-chain alkylamine, Amberlite LA-2, aggregations of ammonium chloride salt of alkylamine and zinc-complex with alkylamine and distribution equilibrium of zinc were investigated at 30 C using n-hexane as a diluent. The ammonium chloride salt of alkylamine exists as monomeric, dimeric, trimeric and tetrameric species (BHCl, (BHCl)2, (BHCl)3 and (BHCl)4, respectively). The zinc-complex exists as monomeric and dimeric species ((BH)2ZnCl4 and ((BH)2ZnCl4)2, respectively). Zinc is extracted according to the extraction reaction in the lower loading region of zinc to alkylamine and according to the extraction reaction in the higher loading region.

KINETICS OF EXTRACTION AND STRIPPING OF COPPER WITH ANTI 2-HYDROXY-5-NONYLBENZ0PHENONE OXIME

ABSTRACT Kinetic studies of extraction of copper with anti 2-hydroxy-5-nonylbenzophenone oxime and stripping of copper were carried out in a stirred transfer cell, along with studies of extraction equilibrium of copper with the extractant and adsorption equilibria of the extractant and the copper chelate complex between the organic and aqueous solutions at 303 K. The extraction and stripping rates were analyzed by an inter-facial reaction model between the adsorbed extractant and the adsorbed 1:1 copper chelate complex accompanied with the mass transfer rates of the species. Furthermore, the extraction rate was simulated by using the equilibrium and reaction rate constants obtained from the analysis.

CHANGE OF SIZE DISTRIBUTION OF POLYMER DROPLETS WITH TIME IN STYRENE SUSPENSION POLYMERIZATION UNDER ULTRASONIC IRRADIATION

Suspension polymerization of styrene under ultrasonic irradiation was carried out and the change of size distribution of polymer droplets with the lapse of polymerization was measured. A stable cohesion effect of ultrasonics in the low conversion region of the monomer made the size of polymer droplets larger than those under no irradiation. However, the stable cohesion effect of ultrasonics in the high conversion region of the monomer was held even under the condition in which a caking effect takes place under no irradiation, and it made a stable operation of suspension polymerization possible.

Protein Extraction by Reversed Micelles Using New Surfactants

ABSTRACT A surfactant plays a key role in the protein extraction by reversed micelles. In this study, extraction of some proteins by new reversed micelle was carried out using dioleyl phosphoric acid (abbreviated DOLPA) instead of conventional surfactant AOT. Large protein more than 50000 of molecular weight, which is difficult to dissolve into AOT reversed micelle, could be easily extracted by DOLPA reversed micelle. Denaturation of the proteins was depressed by using DOLPA reversed micelle because of the poor solubility of the DOLPA to the aqueous solution. Further, hybrid reversed micelle of DOLPA and AOT was investigated. It is found that extracted ratio of a - chymotrypsin was increased by use of the hybrid reversed micelle.