摘要:

A liquid phosphine oxide has been developed with a phosphoryl concentration of 2.3M, twice the maximum that can be reached in TOPO solvents at 50°C. Distribution coefficients are increased by 2mwhere m relates to mols phosphoryl in the extracting complex. The value of m is 1.6 for phenol, 1.0 for acetic acid and 0.9 for ethanol. Kinetics are unchanged. Costs of extracting phenol with the new extractant and with isopropyl ether are compared. Extraction coefficient and separation factor for ethanol are compared with other potential extractants.

ISSN:0736-6299    

DOI:10.1080/07366298808917932

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Environmental considerations dictated the necessity of reducing the phenol content of a waste water to less than 1 PPM. Tests were conducted in a 2 inch diameter column and the test column was optimized with respect to plate spacing and volumetric efficiency. The production unit, scaled up from the test unit, was 5 ft. in diameter. Waste water levels of 0.1 to 0.2 ppm phenol in the raffinate were obtained for feed flows ranging from 150 to 350 gpm and phenol contents in the feed from 400 to 1100 ppm. The empirical scaleup procedure was verified.

ISSN:0736-6299    

DOI:10.1080/07366298808917933

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Extraction of Np with di-isodecyl phosphoric acid (DIDPA) from HN03 solution containing H2O2>was studied from the aspect of the extraction mechanism and the enhancement of the extraction rate. Neptunium initially in the pentavalent oxidation state can be extracted into DIDPA even without any redox agents, but the extraction rate is rather slow. In the present work, H2O2was found to accelerate the extraction. The rate was almost proportional to the 1/2-power of H2O2concentration. Dependence of the extraction rate on HN03 concentration was also examined.

ISSN:0736-6299    

DOI:10.1080/07366298808917934

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Distribution equilibria of Np and Pu in various valence states and stripping of Np(V) were studied in a system involving 0.20 M n-octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide + 1.2 M tributyl phosphate in dodecane as a solvent. Np(V) is weakly extractable at <2 M nitric acid but more effectively extractable at >3 M nitric acid, due to the disproportionation of Np(V) to Np(IV) and Np(VI). Addition of nitrous acid to solutions containing Np(V) increases the over-all extractabllity of Np, due to its partial oxidation to Np(VI). This is also the case In the presence of oxalic acid, both at room temperature and at 40°C. Both Np(IV) and Np(VI) are highly extractable, but the reduction of Np(V,VI) to Np(IV) is slow even with a reductant as strong as sodium formaldehyde sulfoxylate. Pu(IV) is highly extractable and its reduction to Pu(III) with sulfoxylate Is incomplete in the two-phase system if the aqueous phase contains >0.5 M nitric acid. Extracted Np(VI) can be stripped by reduction to Np(V). The stripping rate is, however, slow with nitrous acid as the reductant at low nitric acid concentration. The reduction of Np(VI) by hydrogen peroxide is fast, but is followed by further reduction to Np(IV). Sulfurous acid reduces Np(VI) rapidly and, if no iron is present, only to Np(V), but Fe(II) induces further reduction to Np(IV).

ISSN:0736-6299    

DOI:10.1080/07366298808917935

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Synergistic extraction has been demonstrated for nickel(II) with 5,8-diethyldodecan-6-oxime-7-ol (DEHO), the active component of LIX63 and a range of carboxylic acids including aliphatic and aromatic derivatives. The synergism was shown to depend on the nature of the carboxylic acid with a linear dependance between the pKaof the acid and the synergistic coefficient as defined by the difference in pH50between that obtained by the mixture of extractants and that of DEHO along.

ISSN:0736-6299    

DOI:10.1080/07366298808917936

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

By spectrophotometry experiments, the aquation of tris (benzoylacetonato )iron (III ), [Fe (bza)3], in aqueous acid perchlorate solutions is found to be controlled by the dissociation of the last ligand from the [Fe (bza ) ]2+species and accelerated by hydrogen ions. However, two controlling processes are found in the back-extraction of this complex in carbon tetrachloride into similar aqueous solutions. When the acid concentration is high, a rapid process takes place in the early stage and slow one follows thereafter but when the acid concentration is low, the former is not clearly observed and only the latter is found. This is explained in terms that the rapid process corresponds to the dissociation of two ligand anions among three in the [Fe (bza )3] species in the aqueous phase while the slow process corresponds to the dissociation of the last ligand from the [Fe (bza ) ]2+species after a transient equilibrium is established among the rest of complexes in the system. From these, it is concluded that the higher acid concentration in the washing solution is favorable in order to shorten the time for the back-extraction because it enhances the rate of aquation of the complexes and also increases the total amount of the charged complexes in the aqueous phase.

ISSN:0736-6299    

DOI:10.1080/07366298808917937

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Lanthanide(lII) chelates with 1,1,1 -trif luoro-5,5-dimethyl-2,4-hexanedione form adducts with benzilic acid, an a-hydroxycar-boxylic acid, in chloroform. The order of. the adduct formation constants in magnitude is: Lam> Eum> Ybmalthough it is known that the stability constant of lanthanide(III) complexes with α-hydroxycarboxylic acids in aqueous solutions increases with increasing atomic number.

ISSN:0736-6299    

DOI:10.1080/07366298808917938

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The properties and analytical applications of a new type of selective sorbents - fibrous materials filled with completing ion excnahgers - POLYORGS XI-N and Polyarsenazo-n - were considered. This type of sorbents consist of porous hydrophilic fibres containing fine-grained polymeric sorbents (fillers). The sorptive and kinetic properties of these materials were measured. These sorbents are sufficiently selective and exhibit high sorptive capacity and fast kinetics. The sorbent POLYORGS XI-N has been used for preconcentration of noble metals from natural and industrial materials. The analytical determination were performed by atomic absorption spectrometry of a suspension of the filler in N,N-dimethylformamide. The sorbent Polyarsenazo-n was used for preconcentration of uranium and rare earths prior to their determination in waters.

ISSN:0736-6299    

DOI:10.1080/07366298808917939

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Cation exchange equilibrium distribution coefficients are presented for the chloride complex forming elements Hg(II), Bi(III), In, Cd, Pb(II), Fe(III), Ga, Zn, Cu(II) and Te{IV) with a macroporous (macroreticular) cation exchange resin in nitric acid of concentrations ranging from 0.20 to 5.00 M.Known distribution coefficients (from the literature) for similar concentrations of hydrochloric acid are included for comparative purposes and the influence of chloride complex formation is discussed. Separations which are possible by using both HC1 and HNO3as eluting agents are demonstrated by two elution curves separating the mixtures Hg(II)-Bi(III)-Zn-Pb(II); and Tl(III)-Bi(III)-Cu(II)-Fe(III).

ISSN:0736-6299    

DOI:10.1080/07366298808917940

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The removal of cadmium ions by anion exchange from 55-65 w% H3PO4at 90°C in the presence of small amounts of halides was investigated. Iodide appears to be the most effective additive. Cd distribution coefficients, K = [CD]/[Cd] (w/w), of a few thousand were obtained at equilibrium concentrations of a few hundred ppm iodide in the solution. The stability constants of CdIi. complexes in 55-65 w% H3PO4are much higher than in diluted aqueous solutions and the negatively charged CdIi. complexes have a high affinity for the amine groups of the resin. Stability constants Bi. of CdIi. complexes in concentrated phosphoric acid were determined by using differential pulse polarography. A tentativedescription of the complexation and ion-exchange equilibria assuming adsorption of only one negatively charged Cd species(CdI3−) or CdI42−) is presented. The removal of I-from the phosphoric acid solution exchange was also investigated. Iodide distribution coefficients of about 300 w/w were obtained for a weekly basic resin at an iodide loading of 0.22 mol/kg dry resin.

ISSN:0736-6299    

DOI:10.1080/07366298808917941

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor