Separation of Metals from Sulfated Deep-Sea Ferromanganese Nodules with Organic Precipitating Reagents and Adsorptive Bubble Techniques

Abstract

Organic precipitating reagents and adsorptive bubble techniques were used to separate copper, cobalt, nickel, and manganese from the leach liquors of sulfated deep-sea ferromanganese nodules. Recoveries of the four elements were examined as a function of pH and the quantity of the organic precipitating reagent added. Three reagents were studied: 8-hydroxyquinoline, ammonium 1-pyrrolidine-dithio-carbamate, and dithizone.     

Organic Chemistry of Macromolecules

Abstract

Polymers as reagents in organic synthesis may offer certain advantages over low molecular weight reagents. Examples given include cyclization reactions, Dieckmann reactions, acylation and alkylation of active methylene esters, intrapolymeric reactions, hydrogenation of cyclic olefins, and hydrolysis of esters. The influence of cooperative effects and hydrophobicity on the self-acceleration and allosteric effects on some of these reactions is discussed.     

Xanthan Precipitation from Solutions and Fermentation Broths

Abstract

Precipitation of xanthan from solutions and fermentation broths is studied. The effects of different precipitating agents, initial xanthan concentrations, and salt additions on xanthan solutions are examined. The effect of sodium and calcium chloride concentrations added to isopropanol (IPA) is studied for xanthan solutions. Xanthan precipitation from fermentation broths has been carried out, and the effect of salt addition to IPA is considered.     

Assembly of a water-insoluble strontium metal–organic framework with luminescent properties

A new strontium metal–organic framework, [Sr₂(BTEC)(H₂O)₄]?2H₂O (1) (H₄BTEC = benzene-1,2,4,5-tetracarboxylic acid), has been successfully synthesized by mixing the starting reagents. The single-crystal structure analysis showed that compound 1 displayed three-dimensional structures containing inorganic motifs with two-dimensional layers pillar-connected through organic linkers and forming water-coordinated neutral framework. Further studies revealed that compound 1 was insoluble in water and that it emitted strong luminescence at approximately 437 nm after dehydration.     

Facilitated Transport of Gold through a Membrane via Complexation to Thiourea-Based Reagents

Abstract

The facilitated transport of Au(III) from hydrochloric acid solutions through double solid supported liquid membranes (SSLMs) is reported. The organic phase consisted of a chloroform solution of thiourea-based extraction reagents, dodecyl-thiourea (DTH) or nonylthiourea (NTH), physically absorbed onto microporous polypropylene films, Celgard 2500 or Celgard 2400 (Celanese Plastic Inc.). A cell composed of three compartments, including a reservoir of organic solution, with double SSLM was used in this study. Aqueous solutions of thiourea, KSCN, or Na₂S₂O₃ were used for removing Au(III) from the membrane phase. The permeability coefficient, P, of the SSLM was determined from the slope of Iog[Au]/[Au]_o or log A/A_o vs time plot. The influences of the stirring rate in aqueous feed and organic solutions, of the stripping reagents and their concentration, of the carrier concentration, and of the concentration of HCl in the aqueous feed on the permeability coefficient were determined. A model describing the transport mechanism consisting of diffusion through a feed aqueous diffusion layer, a fast interfacial chemical reaction, and diffusion through the membranes is reported. The study also demonstrates the suitability of the liquid membrane technique to use reagents with low solubility in organic solutions for the permeation of Au³⁺ without problem of solid-phase formation.

     

Anwendung von Erdalkalidodecylsulfaten zur Reinigung von mit polycyclischen aromatischen Kohlenwasserstoffen (PAK) kontaminiertem Bodenmaterial in geschlossenen Tensid‐ und Wasserkreisläufen

Sodium dodecylsulfate solutions contaminated with polycyclic aromatic hydrocarbons (PAH), e.g. pyrene, were purified by addition of calcium or barium salt solution and precipitation of the corresponding calcium or barium dodecylsulfate. The precipitates were cleaned up using several organic solvents. Regeneration of sodium dodecylsulfate from the calcium dodecylsulfate precipitate was possible by solving the substance in an ethanol/water mixture (1:1) and precipitation of calcium hydroxide using sodium hydroxide as a precipitating agent. It was shown, that the calcium dodecylsulfate can be used directly as a tenside in a hot water solution or in an ethanol/water mixture. An extraction procedure could be developed, to remove the PAH contaminations quantitatively from the tenside solutions and concentrate them to small quantities by distillation of the organic solvents. It was demonstrated, that closed cycles of reagents in low need of energy are possible. The procedure was tested at a perylene contaminated kaolin sample.     

Nuclear magnetic resonance spectral analysis of polymer-supported reagents and catalysts

High resolution and cross-polarisation/magic angle spinning nuclear magnetic resonance spectroscopy of crosslinked polystyrene and of reagents and catalysts supported on crosslinked polystyrene and silica gel are reviewed. The materials studied include ionexchange resins, resins in solid phase peptide synthesis, organic synthetic reagents, phase transfer catalysts, transition metal catalysts, and liquid chromatography column packings. ¹³C and ³¹P n.m.r. spectra have been used to identify structures and to study macromolecule and micromolecule dynamics. New spectra of crosslinked polystyrenes and supported reagents are reported. Procedure to obtain qualitative and quantitative spectra are recommended.     

Removal of Zinc Ions from Aqueous Chloride Solutions by Solvent Extraction Using Alamine 308

Abstract

A study has been undertaken to develop a solvent extraction system for zinc with Alamine 308 in aqueous chloride medium. The parameters investigated included reagent concentration, acid concentration, pH, aqueous to organic phase ratio, and rate of extraction and stripping. The study shows that zinc can be extracted rapidly and efficiently from aqueous chloride solutions. A number of aqueous stripping reagents removed more than 90% of the zinc from the organic phase with only one equilibration.     

The Synthesis and Decomposition of Novel Organophosphorus Complexants

Abstract

Aqueous soluble organic diphosphonic acids have been synthesized as aids in the extraction/recovery of metal values from nuclear waste, ground water, or hydrometallurgical processes. The reagents form aqueous soluble complexes at very low pH values (< 1). After use, these compounds do not represent an additional waste management problem as they are readily decomposed to innocuous materials (phosphoric acid and carbon dioxide) by warming and/or by the action of a mild oxidizing agent.     

Optimization of NOM Removal during Water Treatment

Abstract

The aim of this paper is to describe the removal efficiency of individual fractions of natural organic matter (NOM) and the aluminum transformation during treatment of two types of surface water with an increased concentration of NOM of various origins. The coagulation conditions (dose of destabilization reagent and reaction pH value) were optimized for the best NOM and aluminum removal. The results show that the NOM removal efficiency depends on the NOM character, using destabilizing reagents and reaction conditions. The optimized doses of destabilization reagents influence especially the removal of hydrophilic charged (CHA) and very hydrophobic acids (VHA) fractions during treatment of both types of raw water. In contrast to this, the removal of hydrophilic neutral (NEU) fraction is very low (? _NEU =0.13–0.22). The optimal destabilization reagent dosage is characterized by the lowest content of the total reactive aluminum concentration and relatively low concentration of dissolved organic aluminum.     

A convenient synthesis of novel 1,3-phenylene bridged bis-heterocyclic compounds

Reactions of bis-hydrazonoyl bromide 1 with each of phenyl-5-arylidene-2-thioxo-thiazol-4-one, triazinethiones and 4,6-dimethyl-2,6-dioxocyclohexane-1-thiocarboxanilide as sulfur dipolarophilic reagents led to the formation of the hitherto unreported 1,3-phenylene bis-heterocycles 4, 8 and 10, respectively. The structures of the isolated products were established on the basis of their elemental and spectral analyses. The mechanism and the site selectivity in the studied reactions are discussed.     

Control of the Anisotropic Structure of Cellulose Hydrate Films by Variations of Coagulation Variables

Abstract

The evolution of the structures, that developed in cellulose hydrate films from a rayon after coagulation in the precipitating bath from organic solvent, water and sulfuric acid in presence of inorganic salt has been investigated. The specific features of structure formation at coagulation and cellulose hydrate film extension have been found. It was shown that there is a high diversity of supermolecular structures, whose morphology depends on the precipitation conditions and preliminary orientation. The films structure characteristics correspond to its strength properties. An increase in salt concentration resulted in a films with a more homogeneous, tensile strength structures and small sizes of spherulites. The films of high resistance is formed, in a precipitation bath of organic solvent, because of the realization of the liquid crystalline phase in the coagulation process.     

Synergism and Aggregation in Multi-Extractant Solvent Extraction Systems

ABSTRACT

Several combinations of lipophilic extractants have been studied with the objective of investigating the synergistic behavior of metal ion extraction and its relation to reverse micelle formation. Combinations of acidic and neutral extracting reagents that have displayed synergic behavior in other studies were tested. While most of these either showed limited synergy or no correlation with water uptake under the conditions used here, two of the systems showed extraction synergy. These two extraction systems: 2-bromodecanoic acid with 2,2?:6?,2?-terpyridine; and tributyl phosphine oxide with 2-thenoyltrifluoroacetone were modeled based on two different theoretical approaches: microemulsion-assisted extraction; or the formation of mixed complexes in the organic phase. Comparisons between the two models showed that in the case of bromodecanoic acid and terpyridine the approach of mixed complexes provided a somewhat better fit while the second system was not modeled well with either approach. Further work on the species present in the organic phase is needed to determine the role, if any, of aggregates in synergistic solvent extraction systems.     

POLY-(DIPHENYLPHOSPHINYLMETHYL)ARENES - NEW ORGANOPHOSPHORUS EXTRACTANTS OF TRANS-PLUTONIUM ELEMENTS

ABSTRACT

The extraction properties of poly-(diphenylphosphinylmethyl) arenes in which the fragments of different methyl substituted aromatic compounds serve as hard bridges connecting the P=0 functional groups was studied. The extraction of trivalent transplutonium elements and rare earth elements, uranium (VI), plutonium (IV) by chloroform solutions of these reagents as function of HNO₃, and ligands concentration was investigated. The selectivity of reagents was found to depend only on mutual arrangement of P=0 groups in the bridge regardless of their number. Conformational analysis of the reagents described have been used to establish their structure and cause of their selectivity with respect to one or another element.     

STUDY OF KINETIC FACTORS AFFECTING THE EFFICIENCY OF SEPARATION OF TRANSPLUTONIUM AND RARE-EARTH ELEMENTS DURING THE EXTRACTION BY DI-(2-ETHYLHEXYL)PHOSPHORIC ACID

ABSTRACT

The kinetics of the extraction of transplutonium and rare-earth elements with HDEHP from solutions of different complex-forming reagents has been studied. The possibility of the Improvement of intragroup separation of these elements with the use of dynamic factors has been demonstrated     

Quantitative Analysis of Mixtures of Metal Ions by the Ring-Oven Method: Uranium-Thorium-Zirconium-Titanium and Thorium-Cerium-Zirconium-Titanium

Abstract

Successful schemes for the separation of the constituents in the mixtures U-Th-Zr-Ti and Ce-Th-Zr-Ti have been worked out, using the ring-oven method. The constituents are first separated in the form of thin rings. The rings are then developed with selective organic reagents. For the determinations, the intensities of these rings are then compared visually with standard rings, similarly prepared with known amounts. The time required for complete separation and determination of the constituents is about 60–70 min, excluding the time required for the preparation of the standard scales. Separations are possible down to the following concentrations. Ce, 2.1 μg; Th, 3.5 μg; Ti, 0.36 μg; U, 1.8 μg; Zr, 2.7 μg.     

Synthesis of nanocrystalline sinteractive 3Y-TZP powder in presence of ammonium sulphate and poly ethylene glycol

Abstract

Nanocrystalline 3 mol.-% yttria doped tetragonal zirconia polycrstal was synthesised by coprecipitation method. Presence of ammonium sulphate (inorganic) and polyethylene glycol (organic) in optimised quantity in the precipitating bath facilitated formation of an easily filterable precipitate. Calcination of this precursor at 800°C yielded soft agglomerated nanocrystalline powder (～22 nm). Compaction behaviour of the calcined powder as well as pore size distribution of the compact mass indicated formation of soft agglomerate. Owing to its high sinteractivity, this powder could be sintered to ～95% of its theoretical density (%TD) at temperature as low as 1150°C. At 1200°C, the powder compact densified to >98%TD.     

The effect of additives on hydrodesulfurization of dibenzothiophene over bulk molybdenum sulfide: Increased catalytic activity in the presence of phenol

The effect of various additive organic reagents on the activation of MoS₃ as molybdenum sulfide catalyst precursor during hydrodesulfurization reaction of dibenzothiophene was studied. It was found that the presence of phenol or 1-naphthol greatly promoted the activity of the catalyst, while tetralin, 9,10-dihydrophenanthrene, ethylbenzene, and pyridine reagents were found to be detrimental for the activity of the catalyst.     

Acid‐Base and Organic‐Water Distribution Equilibria for Symmetrically‐Substituted P,P′‐Dialkyl Alkylenebisphosphonic Acids

Abstract

P,P′‐dialkyl alkylenebisphosphonic acids are powerful metal extraction reagents. The acid dissociation constants for a homologous series of aqueous‐insoluble P,P′‐di‐3‐(trimethylsilyl)‐propyl and aqueous‐soluble P,P′‐diethyl methylene‐, ethylene‐ and propylene‐ bisphosphonic acids were determined in a 70∶30 w/w methanol‐water solvent by potentiometric titration and ³¹P NMR spectrometry. The values obtained for the diethyl‐substituted acids were compared with those determined in water and used to assess the effect of the medium on the aqueous acid dissociation constants of the lipophilic series of P,P′‐di‐3‐(trimethylsilyl)propyl alkylenebisphosphonic acids. The dependence of the organic/aqueous distribution equilibrium on the aqueous acid concentration was also investigated using electrospray ionization mass spectrometry. The acid dissociation and organic/aqueous distribution properties of the substituted alkylenebisphosphonic acids are discussed in terms of their influence on metal ion extraction.     

Analysis of solar and artificial UVA irradiations on the photo-Fenton treatment of phenolic effluent and oilfield produced water

Abstract

In general, the oil industry has been searching for ways to alleviate the abundant disposal of oilfield produced water, which contains dissolved hard-removal and highly toxic organic compounds. Advanced oxidative processes (AOPs) have revealed to be effective in the degradation of organic compounds, because they generate hydroxyl radicals with high oxidizing potential which are capable of degrading these compounds. The present study has demonstrated the degradation efficiency of effluents containing organic compounds although the photo-Fenton process using a tubular photochemical reactor under different energy sources. This reactor allowed the use and evaluation of two ultraviolet irradiation sources, the sun and black light lamps, besides other relevant variables to the process, such as reagents concentration and the irradiated area, using a model effluent containing phenol. A sample of oilfield produced water was photochemically degraded through the optimum experimental conditions found for the phenol degradation. Solar irradiation was more efficient than lamplight, and it corresponds an important factor for the reduction of operating costs of this process. The solar reaction system applied to the oilfield produced water showed a removal of organic components up to 76%.