Removal of Toxic Elements from Copper Electrolyte by Solvent Extraction

Abstract

Extractants and processes used and proposed for recovery of arsenic, antimony and bismuth from copper electrolytes are presented and discussed. The use of the following extractants is duscussed: tributyl phosphate, partial esters of phosphoric acid (mono(2-ehtylhexyl)phosphoric acid, bis(2-ethylhexyl)phosphoric acid and mono(isooctadecyl) phosphoric acid, - DS 5834), esters of alkylphosphonic acids, trialkylphosphine oxide, CYANEX® 923 extractant, hydroxamic acids, LIX 1104, alcohols (2-ethyIhexanol and others), hydrophobic diols and alkylpolyphenols. The chemistry and processes are presented and discussed.     

Mechanism of synergistic extraction of rhenium(VII) by primary amines and neutral phosphorus esters

It has been found in the present study that Re(VII) can be quantitatively separated from Mo(VI) in alkaline solutions by synergistic extraction with primary amine and neutral phosphorus esters. The mechanism of synergistic extraction was studied. Results of extraction with combinations of different donor and acceptor solvents indicated that during extraction hydrogen bonds were formed between perrhenic acid and active hydrogen atoms of primary amines as well as between the acid and active phosphoryl oxygen of neutral phosphorus esters. The composition of the synergistic extraction adduct was studied and its structure was also proposed. This newly found extraction system is important to the extraction and separation of Re(VII) and also to the studies of mechanism of synergistic extraction.     

Extraction Separation of Scandium，Iron and Lutetium with Isopropyl Phosphonic Acid Mono（1－hexyl－4－ethyl）OctylEster

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Analysis of pesticide residues by chemical derivatization. V. Multiresidue analysis of eight phenoxyalkanoic acid herbicides in natural waters

A multiresidue method is presented for the gas-liquid chromatographic determination of phenoxyalkanoic acid herbicides in natural waters. Extraction efficiencies of different organic solvents are considered in developing a solvent extraction scheme for these herbicides from water. Reactions for derivatizing these compounds by using pentafluorobenzyl bromide, boron trichloride-2-chloroethanol, and dicyclohexylcarbodiimide-2-chloroethanol were studied in order to obtain extracts with low blanks to provide the lowest detection limits. Advantages and disadvantages of the 3 methods are discussed. Retention times are twice as long for the pentafluorobenzyl (PFB) esters as for the 2-chloroethyl (2-Cl) esters under the same conditions, although electron capture sensitivity to the former was greater. The PFB esters are easier to form, but the 2-Cl reaction is more specific for these herbicides. Solutions from the boron trichloride reaction gave the cleanest blanks.     

Modification of official method for analysis of carotenes and xanthophylls in dried plant materials and mixed feeds

The official method (43.018-43.023) for extraction and separation of carotenes and xanthophylls in dried plant materials and mixed feeds is modified. These pigments are extracted from samples lacking xanthophyll esters by stirring 2 hr, followed by 1-hr cold saponification. The official method recommends 16-hr static extraction preceding the cold saponification. For samples containing xanthophyll esters, we preceded the 20-min hot saponification step by 2 hr stirring. This extra step increased the yield of mono- and dihydroxy pigments, especially from marigold meal. For separation, Merck silica gel 60 plus Hyflo Supercel is substituted for silica gel G in adsorbent I, resulting in 30-min separation. Also, at least 4 separations can be performed using the same adsorbent, and the column is more easily cleaned between separations. Results of the modified method were comparable to those of the official method.     

Synergistic extraction of cerium from sulfuric acid medium using mixture of 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester and Di-（2-ethyl hexyl） phosphoric acid as extractant

Synergistic extraction of cerium(IV) from sulfuric acid medium using mixture of 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester(HEH/EHP, HL) and Di-(2-ethyl hexyl) phosphoric acid (HDEHP, HA) as extractant was investigated. The results indicated that the maximum synergistic enhancement coefficients were obtained at the mole fraction of HEH/EHP=0.6, and cerium(IV) was extracted into organic phase in the form of Ce(SO4)0.5HL2A2. A cation exchange mechanism was proposed for the synergistic extraction of Ce(IV). The equilibrium constants and thermodynamic functions such as △G, △H, and △S were determined in the extraction of Ce(IV) from sulfuric medium using mixture of HEH/EHP and HDEHP.     

Solvent extraction characteristics of thiosubstituted organophosphinic acid extractants

Organophosphorus reagents are well known in solvent extraction. Commercial operations for the separation of cobalt from nickel have been successfully carried out using organophosphoric, -phosphonic, and -phosphinic acid extractants. Two new reagents in this class are the mono and dithio analogs of the commercial dialkylphosphinic acid, Cyanex 272. The replacement of oxygen by sulfur in these reagents enables extraction to be carried out at much lower pH.Characterization of Cyanex 272, Cyanex 302 (bis-(2,4,4-trimethylpentyl)-thiophosphinic acid), and Cyanex 301 (bis-(2,4,4-trimethylpentyl)-dithiophosphinic acid) has been undertaken. A comparison of the solvent extraction behavior of metallurgically important first-row transition metal ions from acidic sulfate solution by these reagents is reported. Distribution coefficients shift to lower pH with increasing sulfur substitution and decreasing pK_a of the extractant, the greatest effect being observed for nickel. Stoichiometry of the extraction reactions, and the nature of the metal complexes formed have been determined using slope analysis techniques and spectroscopic measurements.     

Focused antithrombotic therapy: novel anti-platelet salicylates with reduced ulcerogenic potential and higher first-pass detoxification than aspirin in rats

The use of aspirin as an anti-platelet drug is limited by its propensity to induce gastric injury and by its adverse effect on vascular prostacyclin formation. Two phenolic non-steroidal anti-inflammatory drugs (salicylic acid and diflunisal) were modified by esterification with a series of O-acyl moieties. The short-term ulcerogenic in vitro and in vivo anti-platelet properties, pharmacodynamic profiles, and extent of hepatic extraction of these phenolic esters were compared with aspirin (acetylsalicylic acid). The more lipophilic esters (longer carbon chain length in O-acyl group) show significantly less gastrotoxicity in stressed rats than does aspirin after a single oral dose. The in vitro and in vivo anti-platelet studies show that these phenolic esters inhibited (1) arachidonate-triggered human platelet aggregation and (2) thrombin-stimulated rat serum thromboxane A2 production by platelets in the clotting process almost as effectively as aspirin. The hepatic extractions of these O-acyl derivatives are significantly higher than those of aspirin. The pharmacodynamic studies show that these O-acyl derivatives of salicylic acid and diflunisal probably bind to, or combine with, the same site on the platelet cyclooxygenase as aspirin. Replacing the O-acetyl group with longer chain O-acyl moiety in this series of phenolic esters markedly reduced the potential of these agents to induce short-term gastric injury but did not lessen their activity as inhibitors of platelet aggregation. These non-acetyl salicylates may therefore represent a novel class of anti-platelet drugs with less ulcerogenic potential.     

Structure and properties of levextrel resins

Styrene/divinylbenzene based copolymers having a macroporous structure and containing phosphoric acid esters are taken as an example to describe characteristics of the Levextrel resins. They bridge the gap between ion exchange and solvent extraction methods. Up to now, they have mainly been tested for metal refining.     

Extraction and separation of In(III), Ga(III) and Zn(II) from sulfate solution using extraction resin

The separation of In(III), Ga(III) and Zn(II) from sulfate solution has been studied using an extraction resin containing 2-ethylhexyl phosphoric acid mono(2-ethylhexyl) ester (P507 extraction resin). The effect of pH on the extraction of each metal was determined. Extraction isotherms were then constructed at selected pH. Results show that In(III) is first extracted from aqueous solutions at pH 2.0 using this resin while Ga(III) and Zn(II) are co-extracted at pH 3.0. Their separation can be carried out using HCl of different concentrations as eluants. The saturation adsorption capabilities of indium(III) and gallium(III) were evaluated as 47.2 and 31.0 mg/g or 0.41 and 0.44 mmol/g, respectively. The molar ratio of metal ion: P507 reagent on resin was about 1:3. Loaded resins can be regenerated, and the metals can be recovered selectively. Two fixed-bed columns arranged in-series were successfully used for the separation and recovery of these three metal ions from a multi-component solution.     

TiSiW12O40/TiO2催化剂研究新进展

介绍了固载杂多酸盐TiSiW12O40/TiO2在催化合成乙酸系列酯，丙酸系列酯，丁酸系列酯，氯乙酸系列酯，苯甲酸系列酯，对羟基苯甲酸系列酯，肉桂酸系列酯，葡萄糖系列酯及其缩醛，缩酮中的研究进展，实验表明：TiSiW12O40/TiO2对合成以上各类酯及其缩醛，缩酮均具有良好的催化活性，不仅反应时间短，收率较高，而且可较好地回收循环使用，无废酸排放，工艺流程简单，可降低生产成本。     

Extraction kinetics and kinetic separation of La(III), Gd(III), Ho(III) and Lu(III) from chloride medium by HEHEHP

According to the tetrad-effect, 14 elements of lanthanides can be divided into four groups. In our previous study, a new approach was proposed for the kinetic separation of four rare earth ions La(III), Gd(III), Ho(III) and Lu(III) coming from four groups. In that study, four rare-earth ions were kinetically separated from their coexisting mixed aqueous solutions, by performing liquid-column elution using the aqueous solution containing four lanthanide rare-earth ions as the stationary phase and the dispersed organic oil droplets containing HEHEHP (2-ethyl hexyl phosphonic acid mono 2-ethyl hexyl ester) extractant as the mobile phase. The study of extraction kinetics is very important for understanding the kinetic separation of rare earth ions, which was carried out in this paper. The extraction kinetics of La(III), Gd(III), Ho(III) and Lu(III) by HEHEHP diluted in heptane were investigated using single drop method. The different parameters affecting the extraction rate such as column length, specific interfacial area, rare earth ion concentration, extractant concentration, hydrogen ion concentration and temperature were separately studied and the rate equations are deduced. It is first order with respect to rare earth ion and HEHEHP concentrations, and negative first order with respect to hydrogen ion concentrations. The rate constants at 293.15 K are 10^−6.23, 10^−5.73, 10^−5.58 and 10^−5.43, respectively. The experimental results demonstrate that the extraction rate of La(III), Gd(III), Ho(III) or Lu(III) is diffusion-controlled, and the extraction reaction takes place at the interface rather than in the bulk phase. The extraction model was proposed. Besides, the kinetic separation of rare earth ions by HEHEHP oil drops was discussed.     

Reduction by inhibitors of mono(ADP-ribosyl)transferase of chemotaxis in human neutrophil leucocytes by inhibition of the assembly of filamentous actin

1. Chemotaxis of human neutrophils is mediated by numerous agents [e.g. N-formyl-methionyl-leucyl-phenylalanine (FMLP) and platelet activating factor (PAF)] whose receptors are coupled to phospholipase C. However, the subsequent transduction pathway mediating cell movement remains obscure. We now propose involvement of mono(ADP-ribosyl)transferase activity in receptor-dependent chemotaxis. 2. Human neutrophils were isolated from whole blood and measurements were made of FMLP or PAF-dependent actin polymerization and chemotaxis. The activity of cell surface Arg-specific mono(ADP-ribosyl)transferase was also measured. Each of these activities was inhibited by vitamin K3 and similar IC50 values obtained (4.67 +/- 1.46 microM, 2.0 +/- 0.1 microM and 4.7 +/- 0.1 microM respectively). 3. There were similar close correlations between inhibition of (a) enzyme activity and (b) actin polymerization or chemotaxis by other known inhibitors of mono(ADP-ribosyl)transferase, namely vitamin K1, novobiocin, nicotinamide and the efficient pseudosubstrate, diethylamino(benzylidineamino)guanidine (DEA-BAG). 4. Intracellular Ca2+ was measured by laser scanning confocal microscopy with two fluorescent dyes (Fluo-3 and Fura-Red). Exposure of human neutrophils to FMLP or PAF was followed by transient increases in intracellular Ca2+ concentration, but the inhibitors of mono(ADP-ribosyl)transferase listed above had no effect on the magnitude of the response. 5. A panel of selective inhibitors of protein kinase C, tyrosine kinase, protein kinases A and G or phosphatases 1 and 2A showed no consistent inhibition of FMLP-dependent polymerization of actin. 6. We conclude that eukaryotic Arg-specific mono(ADP-ribosyl)transferase activity may be implicated in the transduction pathway mediating chemotaxis of human neutrophils, with involvement in the assembly of actin-containing cytoskeletal microfilaments.     

Studies on the recovery of uranium from phosphoric acid medium using synergistic mixture of (2-Ethyl hexyl) Phosphonic acid,mono (2-ethyl hexyl) ester (PC88A) and Tri-n-butyl phosphate (TBP)

This paper describes the extraction of uranium from aqueous phosphoric acid medium using (2-Ethyl hexyl) Phosphonic acid, mono (2-ethyl hexyl) ester (PC88A) and tri-n-butyl phosphate (TBP) individually as well as their synergistic mixture in different diluents. The various experimental parameters are investigated to optimize optimise the suitable extraction conditions. Results indicate that a synergistic mixture of 0.90 M PC88A + 0.15 M TBP in xylene, can be used for the extraction of uranium from low phosphoric acid medium. Back extraction studies reveals that among all the common strippants used, 0.50 M solution of (NH₄)₂CO₃ was most suitable. The synergistic mixture of 0.90 M PC88A + 0.15 M TBP as extractant system and 0.5 M (NH₄)₂CO₃ as strippant is used to recover uranium from a conditioned wet process phosphoric acid and from actual radioanalytical waste generated during uranium analysis by modified Davies–Gray method. The recovery is found to be around 80% from conditioned WPA whereas better than 90% from modified Davies–Gray waste.     

Mouse T cell membrane proteins Rt6-1 and Rt6-2 are arginine/protein mono(ADPribosyl)transferases and share secondary structure motifs with ADP-ribosylating bacterial toxins

Mono ADP-ribosylation is a posttranslational protein modification that has been implicated in the regulation of key biological functions in bacteria as well as in animals. Recently, the first cDNAs for eucaryotic mono(ADPribosyl)transferases were cloned and found to exhibit significant sequence similarity only to one other known protein, the T cell differentiation antigen Rt6. In this paper we describe secondary structure analyses of Rt6 and related proteins and show conserved structure motifs and amino acid residues consistent with a common ancestry of these eucaryotic proteins and bacterial ADP-ribosyltransferases. Moreover, we have expressed soluble mouse Rt6-1 and Rt6-2 gene products in which C-terminal tags (FLAG-His6) replace the native glycosylphosphatidylinositol anchor signal sequences. Purified recombinant Rt6-2, but not Rt6-1, shows NAD+ glycohydrolase activity, which is inhibited by the arginine analogue agmatine. Immunoprecipitation of recombinant Rt6-1 and Rt6-2 with anti-FLAG M2 antibody followed by incubation with [32P]NAD+ leads to rapid and covalent incorporation of radioactivity into the light chain of the M2 antibody. The bound label is resistant to treatment with HgCl2 but sensitive to NH2OH, characteristic of arginine-linked ADP-ribosylation. These results demonstrate that Rt6-1 and RT6-2 possess the enzymatic activities typical for NAD+-dependent arginine/protein mono(ADPribosyl)transferases (EC 2.4.2.31). They are the first such enzymes to be molecularly characterized in the immune system.     

Mathematical Modelling of the Liquid-Liquid Extraction Separation of Rare Earths

Abstract

An empirical mathematical model has been developed for the simulation of an integrated solvent extraction circuit consisting of an extractor, scrubber and a stripper. This model is designed to simulate the separation of any lanthanide from a mixed lanthanide feed. The Kremser equation is used to calculate the separation occurring in each section of the circuit. The inputs required for the simulation are the feed composition, separation factors, equilibrium data of the key element under a wide range of conditions, the number of stages and flow rates of the aqueous and organic streams in the circuit. This model has been validated with the experimental data for the separation of Nd from a mixed lanthanide chloride feed with 2-ethylhexyl phosphonic acid mono 2-ethyl-hexyl ester (EHPNA) as an extractant.     

Synthesis and characterization by 1H and 13C nuclear magnetic resonance spectroscopy of 17 alpha-cyano, 17 alpha-aminomethyl, and 17 alpha-alkylamidomethyl derivatives of 5 alpha-dihydrotestosterone and testosterone

17 alpha-Aminomethyl, 17 alpha-acetamidomethyl, and 17 alpha-hemiglutaramidomethyl derivatives of dihydrotestosterone and testosterone have been prepared by hydrocyanation of 3,3'-(ethylenedioxy)-5 alpha-androstan-17-one and 3,3'-ethylenedioxyandrost-5-en-17-one, reduction of the corresponding acetylated 17 alpha-cyanohydrins with lithium aluminium hydride, and acylation of the resulting 17 alpha-aminomethyl derivatives with either acetic anhydride or the mono acid chloride of glutaric acid mono methyl ester. Saponification of the 17 alpha-hemiglutaramidomethyl methyl esters gave the corresponding hemiglutaramido derivatives, while acid hydrolysis of the 3-ethylene ketal group of 17 alpha-acetamidomethyl and 17 alpha-hemiglutaramidomethyl derivatives regenerated the 3-oxo and 3-oxo-4-ene functions. The 17 alpha-configuration of 17-substituted steroids was determined by 1H and 13C NMR and confirmed by comparing with NMR data for 17 alpha- and 17 beta-cyano-17-hydroxyandrost-4-en-3-one, 17 beta-cyano-3,3'-(ethylenedioxy)androst-5-en-17-ol, 17 alpha-alkynyl, and 17 alpha-hexanoic derivatives of dihydrotestosterone and testosterone, of known 17-configurations. Several ambiguous assignments of 13C NMR signals of 17 alpha-substituted steroids and unsubstituted 17 beta-hydroxy or 17-oxo precursors have been resolved using steroid analogs deuterated at positions C5-7, or C16 for androstane derivatives, and at positions C6-7, or C7 for androstene derivatives. 17 alpha-Aminomethyl and 17 alpha-alkylamidomethyl derivatives of dihydrotestosterone and testosterone are useful intermediates for the access to potential ligands of androgen-binding proteins necessary for affinity chromatography purification or affinity-labeling experiments.     

单层LB膜诱导化学沉积银膜的研究

以硬脂酸单层LB膜为基底 ,利用膜亲水端基的诱导作用 ,通过化学沉积法制备了金属银膜。扫描电镜(SEM)观察到银膜表面由直径 2 0 0nm左右的银粒子构成 ,透射电镜 (TEM)分析表明银膜为面心立方结构 ,并对单层LB膜上化学沉积银的机理进行了探讨     

Solvent extraction of nickel and cobalt by mixtures of carboxylic acids and non-chelating oximes

The effect of non-chelating oximes on the solvent extraction of nickel(II) and cobalt(II) by solutions of carboxylic acids (H₂A₂) in xylene has been studied. Synergistic enhancements of extraction were found with aldoximes, but not with ketoximes. The synergistic effects are larger for nickel than for cobalt, with the result that the selectivities of the carboxylic acids for nickel over cobalt are considerably enhanced in the presence of aldoximes. The influence of the molecular structure of the oxime and carboxylic acid components upon the synergistic effects is rationalized in terms of the prevailing stereochemical and electronic effects. The extracted complexes were shown to be octahedral in structure, with the compositions NiA₂(oxime)₄ and CoA₂(oxime)₄.The mixed reagent systems may prove useful for the selective extraction of nickel in the presence of cobalt.     

Extraction of noble metals with macrocyclic compounds III: Extraction with calyxarenes

The third and final part of a review on the extraction of noble metals by macrocyclic compounds, which is devoted to extraction with O-, S-, and N-containing calyxarenes with a generalization of References from 1978 to 2008, is presented. it is noted that no systematic investigations on the extraction of noble metals with calixarenes has been performed until now. most works are qualitative and do not consider the regularities of the influence of the compositions of aqueous and organic phases and the properties of the extractant on the degree of metal extraction. the studied solutions are unlike production ones in regards to composition, and the chemical state of extracted ions in aqueous solutions is not always taken into account. it is emphasized that there is only fragmentary information on reextraction in the literature. the problem of the selectivity of extraction of noble metals with calixarene esters is discussed.