摘要:

This paper deals with identification and study of chemical reactions and interfacial phenomena in liquid-liquid extraction such as: 1) condensed interfacial film formation, 2) supersaturation processes in layers adjacent to the interface and 3) other irreversible interfacial processes. Methods of interfacial phenomena study as well as theoretical models of phase and interfacial reactions are discussed. Main results on inorganic substances extraction kinetics and metal extraction catalysis are included.

ISSN:0736-6299    

DOI:10.1080/07366298408918442

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The extraction behavior of Am(III) from nitric acid by octy1(phenyl)-N,N-diisobutylcarbamoyl methyphosphine oxides, OØD[IB]CMPO, in the presence of tributylphosphate, TBP, has been studied using diethylbenzene, decalin, and normal aliphatic hydrocarbon diluents. Relative to ØD[IB]CMPO alone, mixtures of TBP and OØD[IB]CMPO show a slight enhancement in the extraction of Am(III) from nitric acid solution above 2Mand a moderate decrease in extraction for lower acid concentrations. The net effect of TBP addition to OØD[IB]CMPO (as well as other selected carbamoyl methylphosphoryl extractants) is a relative insensitivity of the distribution ratio of Am(III) to HNO3concentration in the range of 0.5Mto 6Mand facilitated stripping of Am(III) with dilute acid. Since a continuous variation study of Am(III) extraction using mixtures of ØOD[IB]CMPO and TBP at a fixed total concentration revealed no evidence of a mixed complex, the TBP appears to be behaving primarily as a phase modifier

ISSN:0736-6299    

DOI:10.1080/07366298408918443

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The extraction of gallium(III) from hydrochloric acid solutions has been investigated using organophosphorous compounds (Tributylphosphate, trioctylphosphine oxide and di-(2-ethylhexyl)-phosphoric acid) and high-molecular weight amines (Trioctylamine and trioctylmethylammonium chloride). The equilibrium expressions are proposed on the basis of the distribution data.

ISSN:0736-6299    

DOI:10.1080/07366298408918444

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Solvent extraction of cobalt(Il) and nickel(II) in aqueous 1 mol dm−3NaCl solutions with benzoyltrifluoro-acetone(Hbfa) in carbon tetrachloride has been measured in the absence and presence of tetrabutylammonium(tba+). In the absence of tba+, M(bfa)2species is extracted and the extraction of cobalt(II) is better in the higher Hbfa concentration range but in the presence, M(bfa)3−tba+type ion-pair is extracted and the extraction of nickel-(II) is always better. This is explained in terms that although the bis-nickel(II) complex is more stable, it is much more strongly hydrated than the bis-cobalt(II) complex and consequently its extraction is hindered but in the tris-complexes such a large difference of the hydration may not occur and the more stable nickel(II) complex is extracted better.

ISSN:0736-6299    

DOI:10.1080/07366298408918445

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Theoretical comparison of the equilibria and kinetics of solvent extraction (SX) and emulsion liquid membrane extraction (MX) was performed using the distribution ratios at the outer inner boundaries of liquid membrane. Enhancement factors, pertraction factor (p) and multiplication factor (N), were proposed to express efficiency of the MX technique. The extraction of cesium, strontium, cobalt(II), uranium (VI), cerium(III) and technetium(VII) was investigated from this point of view. The most perspective systems are those with chelating agents (e.g. di-2-ethylhexyl-phosporic acid and 8-hydroquinoline), especially at low concentrations (substioichiometric amounts), with which high enhancement factors can be achieved. The results with the ion-exchange systems (bis(1,2-dicarbollyl)-cobalt(III) and quaternary ammonium salts) may be interpreted as indicating some surface barriers which prevent the transport of ions.

ISSN:0736-6299    

DOI:10.1080/07366298408918446

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Hydrous manganese dioxide in a cryptomelane-type showed an excellent ion-exchange selectivity for K+, Rb+and Ba2+ions having the effective ionic radii of about 1.4 Å. Log-log plots of distribution coefficients for alkali and alkaline earth metal ions vs. [HNO3] yielded a straight line with a slope of −1 and −2, respectively, indicating the “ideal” ion-exchange mechanism. The stoichiometry of ion-exchange reactions was also established for the uptake of macro-amounts of alkali metal ions in nitrate media.

ISSN:0736-6299    

DOI:10.1080/07366298408918447

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The H+/Li+ion-exchange in α-titanium phosphate at 25° C was studied and the exchange isotherm obtained. The process occurs with partial decomposition of the exchanger through hydrolysis. X-ray diffraction patterns of the conversion solids heated at 310°C, suggest the existence of two crystalline phases differing from the initial one, TiHLi (PO4)2(d=6.8 Å)and Ti(LiPO4)2(d=7.6 Å). Distribution curves of the solid phases with the characteristic shape of two consecutive chemical reactions were found. The existence of a half-exchanged phase in the Li-conversion allows the behaviour of this material to be considered to follow the same pattern as the behaviour in the H+/M+ion exchange (M=Na,K)

ISSN:0736-6299    

DOI:10.1080/07366298408918448

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The H+/Na+ion-exhange in α-titanium phosphate at 5 and 25°C was studied. Exchange isotherms and titration and hydrolysis curves were obtained. The evolution of the exchanger was followed by X-ray diffraction. The substitution occurs via a half-exchanged crystalline phase. Distribution curves of solid phases with the characteristic shape of two consecutive chemical reactions were obtained. The temperature influence on the α-TiP behaviour was explained from the thermodynamic values of both ion-exchange processes.

ISSN:0736-6299    

DOI:10.1080/07366298408918449

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0736-6299    

DOI:10.1080/07366298408918450

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor