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Pruritus (itch) is a debilitating symptom in liver diseases with cholestasis, which severely affects patients' quality of life. Limited treatment options are available for cholestatic itch, largely due to the incomplete understanding of the underlying molecular mechanisms. Several factors have been proposed as pruritogens for cholestatic itch, such as bile acids, bilirubin, lysophosphatidic acid, and endogenous opioids. Recently, two research groups independently identified Mas-related G protein-coupled receptor X4 (MRGPRX4) as a receptor for bile acids and bilirubin and demonstrated its likely role in cholestatic itch. This discovery not only opens new avenues for understanding the molecular mechanisms in cholestatic itch but provides a promising target for developing novel anti-itch treatments. In this review, we summarize the current theories and knowledge of cholestatic itch, emphasizing MRGPRX4 as a bile acid and bilirubin receptor mediating cholestatic itch in humans. We also discuss some future perspectives in cholestatic itch research.

Two new Schiff base copper(II) complexes, [Cu2L2] (I) and [Cu2L(NCNCN)2]n (II), where L is the dianionic form of N,N'-bis(5-fluorosalicylidene)-1,3-propanediamine (H2L), were synthesized and characterized by elemental analyses, infrared and electronic spectroscopy, and single crystal X-ray determinations (CIF files CCDC. nos. 2000415 (I) and 2000416 (II)). Complex I is a phenolate bridged dinuclear copper(II) compound. Complex II is a phenolate and dicyanoamide bridged polynuclear copper(II) compound. In both complexes, the Cu atoms are in square pyramidal coordination. The Schiff base ligand coordinates to the Cu atoms through the phenolate O and imino N atoms. The Schiff base H2L and the two complexes showed high selectivity and antimicrobial activities against a number of the bacteria and fungi.

Nicotinamide adenine dinucleotide phosphate (NADPH), as a well-known cofactor, is widely used in the most of enzymatic redox reactions, playing an important role in industrial catalysis. However, the absence of a comparable method for efficient NADP+ to NADPH cofactor regeneration radically impairs efficient green chemical synthesis. Alcohol dehydrogenase (ADH) enzymes, allowing the in situ regeneration of the redox cofactor NADPH with high specific activity and easy by-product separation process, are provided with great industrial application potential and research attention. Accordingly, herein a NADP+-specific ADH from Clostridium beijerinckii was selected to be engineered for cofactor recycle, using an automated algorithm named Protein Repair One-stop Shop (PROSS). The mutant CbADH-6M (S24P/G182A/G196A/H222D/S250E/S254R) exhibited a favorable soluble and highly active expression with an activity of 46.3 U/mL, which was 16 times higher than the wild type (2.9 U/mL), and a more stable protein conformation with an enhanced thermal stability: Δ $${T}_{1/2}^{60\mathrm{min}}$$ T 1 / 2 60 min = + 3.6 °C (temperature of 50% inactivation after incubation for 60 min). Furthermore, the activity of CbADH-6M was up-graded to 2401.8 U/mL by high cell density fermentation strategy using recombinant Escherichia coli, demonstrating its industrial potential. Finally, the superb efficiency for NADPH regeneration of the mutant enzyme was testified in the synthesis of some fine chiral aromatic alcohols coupling with another ADH from Lactobacillus kefir (LkADH).

A new copper(II) complex [Cu(L 1 )(NCS)(CH 3 OH)] ( 1 ) and a new zinc(II) complex [ZnCl 2 (HL 2 )]·CH 3 OH ( 2 ), derived from 4-bromo- N' -(pyridin-2-ylmethylene)benzohydrazide (HL 1 ) and 4-methoxy- N' -(pyridin-2-ylmethylene)benzohydrazide (HL 2 ), were prepared and characterized by elemental analysis, IR and UV-Vis spectroscopy and single crystal X-ray diffraction. The hydrazone HL 1 coordinates to the Cu atom in enolate form, while the hydrazone HL 2 coordinates to the Zn atom in carbonyl form. Single crystal structural analyses indicate that the hydrazones coordinate to the metal atoms through the pyridine N, imino N, and enolate/carbonyl O atoms. The Cu atom in complex 1 is in square pyramidal coordination, and the Zn atom in complex 2 is in trigonal-bipyramidal coordination. The inhibitory effects of the complexes on Jack bean urease were studied, which show that the copper complex has strong activity on urease.

A series of five new fluoro-substituted aroylhydrazones were prepared and structurally characterized by elemental analysis, IR, UV-Vis and 1H NMR spectroscopy, as well as single crystal X-ray diffraction. The compounds were evaluated for their antibacterial (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas fluorescence) and antifungal (Candida albicans and Aspergillus niger) activities by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method. The biological assay indicated that the presence of the electron-withdrawing groups in the aroylhydrazones improved their antimicrobial activities.

Powder cohesiveness has a strong correlation with particle adhesion, which is studied using a novel mechanical surface energy tester and a method to measure Bond numbers of the powders. The mechanical surface energy tester measures particle adhesion by detaching particles adhered to a substrate surface. When the substrate is dropped from a set of heights and stopped against a stopper, the particles are subject to a detached force, which in principle is equivalent to the particle adhesion force between the detached particles and the substrate. The detached particles are collected for further particle size analysis. The Bond number of the powders is calculated as a ratio of adhesion to gravity with the particle physical properties measured such as solid density and full-size distribution. In this study, particle adhesion forces for a wide range of sample powders were selected and investigated with powder tabletted substrates (same as the test powders), including Calcium Carbonate, Lactose, Microcrystalline Cellulose, Paracetamol, Ibuprofen and Titanium Dioxide for a wide range of material properties. Influences of substrate materials on the measurements are studied between the powder tabletted substrates and other standardised materials such as mild steel, glass, stainless steel and TIVAR. The study shows that the substrate material has little influence on the measurements of particle adhesion within a maximum variation of about 2.5%. This allows using different substrates for the measurement of Bond numbers. The adhesion forces measured are also compared to those calculated by other established methods, and some correlations have been found.

Nicotinamide adenine dinucleotide phosphate (NADPH), as a well-known cofactor, is widely used in the most of enzymatic redox reactions, playing an important role in industrial catalysis. However, the absence of a comparable method for efficient NADP + to NADPH cofactor regeneration radically impairs efficient green chemical synthesis. Alcohol dehydrogenase (ADH) enzymes, allowing the in situ regeneration of the redox cofactor NADPH with high specific activity and easy by-product separation process, are provided with great industrial application potential and research attention. Accordingly, herein a NADP + specific ADH from Clostridium beijerinckii was selected to be engineered for cofactor recycle, using an automated algorithm named Protein Repair One-stop Shop (PROSS). The mutant CbADH-6M exhibited a favorable soluble and highly active expression with an activity of 46.3 U/mL, which was 16 times higher than the wild type (2.9 U/mL), and a more stable protein conformation with an enhanced thermal stability: Δ = +3.6°C (temperature of 50% inactivation after incubation for 60 min). Furthermore, the activity of CbADH-6M was up-graded to 2401.8 U/mL by high cell density fermentation strategy, demonstrating its industrial potential. Finally, the superb efficiency for NADPH regeneration of the mutant enzyme was testified in the synthesis of some fine chiral aromatic alcohols coupling with anther ADH from Lactobacillus kefir (LkADH). Nicotinamide adenine dinucleotide phosphate (NADPH), as a well-known cofactor, is widely used in the most of enzymatic redox reactions, playing an important role in industrial catalysis. However, the absence of a comparable method for efficient NADP + to NADPH cofactor regeneration radically impairs efficient green chemical synthesis. Alcohol dehydrogenase (ADH) enzymes, allowing the in situ regeneration of the redox cofactor NADPH with high specific activity and easy by-product separation process, are provided with great industrial application potential and research attention. Accordingly, herein a NADP + specific ADH from Clostridium beijerinckii was selected to be engineered for cofactor recycle, using an automated algorithm named Protein Repair One-stop Shop (PROSS). The mutant CbADH-6M exhibited a favorable soluble and highly active expression with an activity of 46.3 U/mL, which was 16 times higher than the wild type (2.9 U/mL), and a more stable protein conformation with an enhanced thermal stability: ΔT60 min 1/2 = +3.6°C (temperature of 50% inactivation after incubation for 60 min). Furthermore, the activity of CbADH-6M was up-graded to 2401.8 U/mL by high cell density fermentation strategy, demonstrating its industrial potential. Finally, the superb efficiency for NADPH regeneration of the mutant enzyme was testified in the synthesis of some fine chiral aromatic alcohols coupling with anther ADH from Lactobacillus kefir (LkADH).

Isobavachalcone (ISO) exhibits good anti-inflammatory activity. We evaluated the renoprotective effects of ISO against diabetic nephropathy (DN). Diabetic rats established by the single injection of streptozotocin (STZ) were orally treated with ISO. The levels of serum creatinine (Scr), blood urea nitrogen (BUN), and 24 hr urinary protein were measured. In this study, ISO effectively ameliorated renal damage by reducing BUN, Scr, and 24 hr urinary protein and also improved kidney pathological appearances. ISO prevented STZ-caused apoptosis in the glomerular tissue in vivo and blocked the high glucose (HG)-induced growth inhibitory effect in human renal glomerular endothelial cells in vitro. Moreover, ISO reduced pro-inflammatory mediator production and blocked the NF-κB pathway in the damaged renal tissues and HG-treated HRGEC cells. Taken together, the results of this study indicate that ISO consumption might have significant beneficial effects on the DN and this action might be correlated with the modulation of the NF-κB pathway. PRACTICAL APPLICATIONS: ISO is an active compound from the dried ripe fruit of Psoralea corylifolia L. seed, which is traditionally served as a food ingredient in Asia. In this investigation, we observed the beneficial effects of ISO on a murine model with DN. Further research revealed that the protective action of ISO might be connected with its weak hypoglycaemic and notable anti-inflammatory effects. Our research data suggest that ISO-enriched food might be a good choice for people suffering from DN.

Ionic liquids have a great potential in capture and separation of carbon dioxide (CO2), and the solubility of CO2 in ionic liquids is one of key data for engineering applications. In this paper, th...

Using p -phenylenediamine (PPD) or p -nitroaniline (PNA) as effective redox additive can largely improve the capacitive performances of supercapacitors when incorporated into KOH solution. And how to vividly differentiate the roles of amine and nitro groups adherent to phenyl ring really is an interesting scientific issue. Herein, with the help of a series of capacitive techniques, it is discerned that the PPD can release two protons and two electrons, while the PNA realizes the gain/loss of one proton and one electron, in particular accompanied with the partial reduction of nitro group. Clearly, introducing PPD or PNA substances into KOH solution can largely improve the specific capacitance as well as the resultant energy densities, but slightly deteriorates the energy efficiency. Besides, the incorporation of PNA leads to higher cycling stability than that of the PPD, which is primarily incurred by the fact that the nitro group adherent to phenyl ring delivers better stability. Furthermore, the potential window of 0–1 V or − 0.5–0.5 V strongly affects the capacitive performances. The present research results are expected to provide us the guidance for the usage of PPD or PNA when incorporated into KOH solution for elevating the supercapacitors' performances.

The adsorbent synthesized from spent Zn-Mn battery was used to purify phosphate from aqueous solution. From the results it could be seen that pH value affected phosphate removal significantly, optimum pH in the purification process was 8.0. The removal rate of phosphate increased when the adsorbent dosage improved. The reaction process was fast and the purification ratio could reach 96.2% for 10 minutes. The adsorption isotherm of phosphate purification fitted Langmuir equation and Freundlich equation. The Q0 value in Langmuir equation was 56.82 mg/g and the n value in Freundlich equation was 3.61. From spent Zn-Mn battery effective adsorbent for phosphate removal could be synthesized.

In this work, magnetic Fe-Cu bimetal oxide modified fly ash was used to remove phosphate from coating wastewater. The influences of pH, dosage amount and adsorption time on the removal of phosphate were investigated. The experimental results showed that pH had a significant effect on the adsorption of phosphate. The removal percentage of phosphate reached a maximum at pH 10. The removal efficiency of phosphate increased with the increase in adsorbent dosage. A kinetic study showed that the phosphate adsorption was well described by a pseudo second order model. The adsorption isotherm of phosphate could be described by the Langmuir model and Freundlich model. The Langmuir maximum capacity Q0 was 12.69 mg/g and the value of n of the Freundlich model was 3.82. The experimental results indicated that magnetic Fe-Cu bimetal oxide modified fly ash was a potential adsorbent for the removal of phosphate from the wastewater.

Many epidemiological studies have evaluated associations of platelet glycoprotein receptor alpha2beta1 integrin (ITGA2) and glycoprotein IIIa (ITGB3) gene polymorphisms with diabetic retinopathy (DR), but the published data are inconclusive. The aim of the present study was to assess the associations by using meta-analysis.A comprehensive electronic search (PubMed, EMBASE, Elsevier Science Direct, CNKI and Wanfang) was carried out until 31 August 2013. Odds ratios (ORs) and its 95% confidence intervals (CIs) were used to assess the strength of the associations.Nine studies including 1678 cases and 1329 controls were included in the meta-analysis. Meta-analysis was performed for ITGA2 gene BgI II polymorphism (7 studies including 758 cases and 570 controls) and ITGB3 gene PlA1/A2 polymorphism (4 studies including 1047 cases and 861 controls). Significant associations were found for BgI II (+ versus -: OR = 1.42, 95% CI = 1.06-1.90, p = 0.02; +/- + +/+ versus -/-: OR = 1.46, 95% CI = 0.99-2.15, p = 0.06; +/+ versus -/- + +/-: OR = 1.90, 95% CI = 1.35-2.67, p = 0.0003) and PlA1/A2 (A2 versus A1: OR = 0.74, 95% CI = 0.52-1.07, p = 0.11; A1A2 + A2A2 versus A1A1: OR = 0.80, 95% CI = 0.64-0.99, p = 0.04; A2A2 versus A1A1 + A1A2: OR = 0.45, 95% CI = 0.27-0.75, p = 0.002) polymorphisms.This meta-analysis demonstrates that DR is associated with ITGA2 BgI II and ITGB3 PlA1/A2 polymorphisms.

Electrostatic charge is generated during powder handling due to particle-particle and particle-wall collisions, rubbing, sliding, and rolling. In case of bipolar charge generation, the electrostatic forces may significantly change the inner forces and increase powder adhesion and cause a serious problem in material handling process. Therefore, the knowledge of distribution of charge across the individual particles is helpful to identify the role of triboelectrification and the effects of various relevant variables especially change in the contact materials, environmental conditions during processing, etc. A novel approach based on inductive sensor has been developed to detect the either polarity of charged particle and to characterise the bipolar charge distribution in the population of particulate material. To achieve this, an amplification unit configured as a pure integrator and signal processing techniques has been used to de-noise and correct the baseline of signal and MATLAB algorithm developed for peak detection. The polarity of charged particles obtained by this method is calibrated with Faraday pail method and the results are promising. Experimental study has been carried out by using two distinct populations of oppositely charged particles (glass beads-PVC, olivine sand, and silica sand). The obtained results indicate that the method is able to detect the distribution of polarities of charged particles.

In this work the adsorption of phosphate using the magnetic Fe-Zn bimetal oxide modified fly ash was studied. The experimental results showed that the effective pH range for the adsorption of phosphate was between 3.0 and 9.0. The removal percentage of phosphate reached maximum at pH 8.0. Kinetic study showed that the phosphate adsorption was well described by pseudo second order model. The removal efficiency of phosphate increased with the increase of adsorbent dosage and the decrease of the initial concentration. The adsorption of phosphate could be described well by Langmuir isotherm, the Langmuir constant Q0 was 24.15mg/g.

The removal of phosphate in digested sludge supernatant by modified coal fly ash was investigated in this study. Modification of the fly ash by the addition of sulfuric acid could significantly enhance its immobilization ability. The experimental results also showed that adsorption of phosphate by the modified fly ash was rapid with the removal percentage of phosphate reaching an equilibrium of 98.62% in less than 5 minutes. The optimum pH for phosphate removal was 9 and the removal percentage increased with increasing adsorbent dosage. The effect of temperature on phosphate removal efficiency was not significant from 20 to 40 degrees C. X-ray diffraction and scanning electron microscope analyses showed that phosphate formed an amorphous precipitate with water-soluble calcium, aluminum, and iron ions in the modified fly ash. Water Environ. Res., 84, 411 (2012).

In this work the fly ash was modified by sulfuric acid for the removal of phosphate. It was found that modification of fly ash could significantly enhance the phosphate immobilization ability of the fly ash. The specific surface area of the fly ash increased from 8.8 to 32.5 m(2)/g after treated with sulfuric acid. The modification of the fly ash also resulted in the mobilization of acid-soluble metal ions due to partial or complete dissolution of the metals under the acidic conditions. Both adsorption and precipitation contributed to the removal of phosphate by the modified fly ash but precipitation was a major mechanism of phosphate removal. The experimental results showed that adsorption of phosphate by the modified fly ash was rapid, the removal percentage of phosphate could reach maximum in 5 min. In the range of 5-9, pH did not significantly affect the removal of phosphate and the removal percentage of phosphate increased with the increase of adsorbent dosage. The adsorption of phosphate by the modified fly ash could be described well by Langmuir isotherm equation, the Langmuir constant Q(0) was 9.15 mg g (1). The XRD patterns and the SEM images of modified fly ash after sorption revealed that CaHPO(4)center dot 2H(2)O was formed in the removal of phosphate. In addition, phosphate also formed precipitate with aluminum and iron. (C) 2010 Elsevier Ltd. All rights reserved.

Crystalline FeOOH and Zn(II) doped FeOOH samples were prepared by a co-precipitation method using ferrous sulphate heptahydrate, Zinc sulphate heptahydrate, ammonia, 3% hydrogen peroxide at 80 degrees C and pH value 3.0. These samples were characterized by XRD and were also chemically analyzed. The XRD patterns of pure FeOOH matched with that of Zn(II) doped FeOOH sample and showed no shift in their d-values, which indicated that Zn2+ ions were adsorbed on the Surface of FeOOH or on the surface of the crystalline lattice, and were not Captured into the fertile lattice. Chemical analysis showed that the molar ratio of Zn(II)/Fe in Zn(II) doped FeOOH sample was only 0.038 when this ratio was 0.5 in an initial reaction Solution. These samples were treated in ammoniacal or sodium hydroxide medium in the presence of ferrous sulphate or cobalt sulphate under hydrothermal conditions. The converted products were analyzed both for ferrous, total iron, cobalt and zinc. Characterization was carried out using instrumental techniques such as SEM, FT-IR, XRD and magnetization characterization. Though the XRD patterns of the converted products Showed presence of only magnetite in the NH3-Fe2+, Co2+-H2O converted medium, the FT-IR spectra and chemical analysis showed an un-reacted FeOOH in the converted product. Even though, the saturation magnetization of this magnetite was higher to 97.489 emu g(-1). Furthermore, higher temperature increased the concentration of Co2+ captured into spinel structure. The conversion were restrained in NH3 concentration of less than 12 g/L and more than 25 g/L. However, increasing of Fe2+/Co2+ ratio in the NH3-Fe2+, Co2+-H2O medium made no distinct difference in the introduction of Co2+ into spinel structure when concentration of Fe2+ was enough. Compared with Zn-free FeOOH, it was difficult for Zn-doped FeOOH to convert to magnetite in the NH3 (NaOH)-Fe2+-H2O medium. Furthermore, alkali species were critical in the above conversion. The content of Zn2+ which was Out of Zn-doped FeOOH solid state and entered into the outer solution was more in the NH3 medium than that of the NaOH medium, but Conversion from Zn-FeOOH into magnetite was easy in the NaOH medium. The explanations of above facts were given in the text. (C) 2008 Elsevier B.V. All rights reserved.

CoFe2O4 magnetic particles were prepared by co-precipitation method in 60 degrees C homogeneous aqueous solution without any subsequent heat treatment. It was found that the mixing procedure and Fe2+/Fe3+ ratio of initial solution were critical in the preparation of CoFe2O4 particles in particle size, magnetization characters, uniformity in particle size and even cation distribution in spinel structure. Two different procedures were used to precipitate CoFe2O4 magnetic particles. Evidenced by XRD, Mossbauer analyses and magnetization determination, particles in comparative uniformity average size were obtained in procedure A, denoted as normal pH regulation procedure, in which NaOH solution was dropped into the mixture solution of iron ions, and with the decreasing in Fe2+/Fe3+ ratio of initial solution, the particle size decreased, which followed the same rule of diversification in saturation magnetization. Uniformity in particle size lowered when procedure B, referred to as reverse pH regulation procedure, where ferrous and cobalt ions were dropped into alkaline solution, was used to precipitate CoFe2O4, In both procedures, with the decreasing in Fe2+/Fe3+ ratio of initial solution, the saturation magnetization decreased, while the magnetic coercivity decreased but increased sharply when Fe2+/Fe3+ ratio of initial solution was 0. (C) 2007 Elsevier B.V. All rights reserved.

Gallium-bearing magnetite particles were synthesized by aerial oxidation of alkaline suspension containing both ferrous and gallium ions. It was found that the mixing procedure and temperature were critical in the preparation of ferrite particles without the formation of α-FeOOH (ferric oxyhydroxide), non-spherical particles and amorphous phase, evidenced by characterization of SEM and XRD. On the other hand, the concentration of Ga3+ entry into the structure of spinel was different with the mixing procedure and temperature. Single phase of spinel gallium-bearing magnetites were precipitated at the temperature from 25 to 90 °C in the C procedure in which the neutralization of Ga was performed firstly, but the concentration of Ga entry into spinel of magnetites decreased with the temperature increasing. While in the procedure D in which neutralization of Fe ions was performed firstly, single phase of spinel gallium-bearing magnetites were precipitated only at the temperature above 65 °C, and the content of gallium precipitated into the magnetites increased with the temperature. Mossbauer analysis and magnetic characteristic were used to investigate the cation distribution of the gallium bearing ferrites with different ratio of Ga3+/Fe2+, which showed small content gallium introduction to have entered the tetrahedral sites preferentially rather than the octahedral sites, and increasing gallium introduction to have located between octahedral and tetrahedral sites.

Clean processing of copper converter slag to reclaim cobalt and copper could be a challenge. An innovative and environmentally sound approach for recovering valuable metals from such a slag has been developed in the present study. Curing the slag with strong sulphuric acid, without re-smelting or roasting as practiced currently in the industry, render it accessible to leaching, and more than 95% of cobalt and up to 90% of copper was extracted together with iron by water leaching, leaving silica behind in a residue. The copper in the leach liquor was recovered by cementation with iron and the dissolved iron crystallized as ferrous sulphate monohydrate. The cobalt in the mother-liquor rich in iron was recovered by either cementation or sulphide precipitation. Operation variables in the new process were also investigated and optimized.

In this work the effect of reaction temperature, sulfuric acid concentration, liquid-to-solid ratio and Fe2+ concentration on sulfuric acid leaching of gallium from phosphorus flue dust was studied. The results showed that gallium extraction increased with the increase of temperature, sulfuric acid concentration and liquid-to-solid ratio. Fe2+ concentration did not significantly affect the recovery of gallium. The acid-soluble gallium could be completely extracted with simulated spent acid containing 20% sulfuric acid and 0 to 50 g/L Fe2+ at temperature of 80 degrees C, and liquid-to-solid ratio of 10:1. The effect of phosphate concentration, reaction temperature and pH on the precipitation of gallium and ferrous iron was also studied in order to determine the optimum conditions for the recovery of gallium from simulated spent acid leach solution. It was found that under optimum precipitation conditions, when all gallium precipitated from the simulated spent acid leach solution containing 31 g/L ferrous iron and 0.1 g/L gallium, the precipitation of iron was less than 2%, the ratio of iron-to-gallium decreased from 3 10:1 in the leach solution to 5:1 in the precipitate. Gallium was therefore concentrated in the precipitate. (C) 2007 Elsevier B.V. All rights reserved.

Colloidal emulsion aphrons (CEAs) can be considered as the micrometer-sized water-in-oil emulsion cores encapsulated by a “soapy shell” consisting of multi-layer surfactant molecules. The emulsion core sizes of CEA dispersion are roughly in 10–100 μm, whereas the sizes of inner phase are in 1–5 μm. CEAs can be used as a microreactor to synthesize fine powder materials. Silver powders with various sizes and shapes were prepared with di-(2-ethylhexyl) phosphoric acid (D2EHPA) as the mobile carrier in membrane phase, ascorbic acid ( V c ) as reducing agent in inner phase and cyclohexane as the membrane of CEAs. The linear silver particles were formed under low mobile carrier concentration in membrane phase or low ascorbic acid concentration in inner phase, whereas the granular silver particles with comparatively small sizes were obtained under the high mobile carrier concentration or high ascorbic acid concentration, and also silver powder of “nano-porous microsphere” was prepared with CEAs by adjusting the D2EHPA concentration in membrane phase, ascorbic acid concentration in inner phase and the molar ratio of silver ion to ascorbic acid ( n A g + / V c ). Compared with emulsion liquid membrane (ELM) method, the silver powder prepared with CEAs was usually in granular form with smaller sizes because of the higher transfer rate, but for that prepared with ELMs was only in linear form. Two kinds of silver powder samples with typical shapes, one is the “nano-porous microsphere” prepared with CEAs and the other is the linear silver powder prepared with ELMs, were characterized by thermogravimetry (TG)–differential thermal analysis (DTA), X-ray powder diffraction analysis and field emission scanning electron microscope (FESEM).

Cobalt ferrite particles were synthesized by aerial oxidation of ferrous and cobalt ions at alkaline condition and room temperature. It was found that mixing procedures of ferrous and cobalt ions and alkaline in initial stage of reaction were critical in mechanisms of the formation of cobalt ferrite and sizes of particles. Smaller particles were precipitated in the procedure in which alkaline solution was dropped into the mixture solution of ferrous and cobalt ions (procedure 1, denoted as normal pH regulation procedure), and with the increase of content of cobalt in the initial solution, the content of Fe(III) in the product decreased which suggested that cobalt ions occupied the location of Fe(III) in the spinel structure, and it is concluded from Mossbauer measurement at room temperature that the transformation from sextet to doublet recorded in the spectrum is typical superparamagnetic (SPM) transition, which depend on increasing of Fe(III) in the Co(II) gelatin with the Co concentration in initial solution. In procedure 2, referred to as reverse pH regulation procedure, where ferrous and cobalt ions were dropped into alkaline solution, with the increase of the ratio of Fe3+/Fe2+ (from 0 to 1) of initial solution, the ratio of Co2+/Fe-(total) in the end product decreased, and the products exhibited strong magnetization that would be in a tight correlation with the ferrite structure, evidenced by XRD analyses. But, the precipitate with the ratio of Fe3+/Fe2+ = 1 of initial solution produced by procedure 1 exhibited no magnetization and brown-red color. The possible mechanisms of the formation of cobalt ferrite in procedure 1 and 2 were given based on analysis of XRD and IR patterns along the reaction time. The cobalt ferrite were produced through green-rust intermediate phase in procedure 1, while were precipitate directly in procedure 2. (c) 2005 Elsevier B.V. All rights reserved.

A new kind of dispersion named as colloidal emulsion aphrons (CEAs) has been prepared and their structure was postulated. They can be considered as the micron-sized water-in-oil (W/O) emulsion-cores encapsulated by a "soapy shell" consisting of multi-layer surfactant molecules. In this work, CEAs were made using span 80 (sorbitan monooleate) as hydrophobic surfactant, NP 10 (nonylphenol ethoxylate) as hydrophilic surfactant and n-heptane as the oil phase. In this dispersion, the emulsion-core sizes are mainly in 10-100 mu m and that of the inner phase droplets are in 1-5 mu m. Some of CEA properties, especially the dispersibility and stability were studied. CEAs disperse more easily in water compared with that of emulsion liquid membranes (ELMs). Some affecting factors, such as deposit time, mixing speed, oil-internal ratio and concentrations of hydrophilic and oil-soluble surfactants on leakages of CEA dispersion were characterized under various conditions by using Co2+ as a tracer ion. In order to gain the high stability and low leakage, suitable surfactant concentrations and oil-inner phase ratio (R-oi) are necessary for CEA preparation. In this study, span 80 and NP 10 were supposed to be in 0.5-2.5% (w/v) and 0.25-0.75% (w/v), respectively and R-oi >= 1. Because of the large interface areas and high dispersibility which CEAs possess, it is hopeful for CEAs to fulfill the requirement of quick extraction without sufficient stirring, such as the treatment of drug overdose or food poisoning. (c) 2005 Elsevier B.V. All rights reserved.

The removal of iron and various heavy-metal ions by their incorporation into stable ferrite-type precipitates at low temperature is a promising alternative to clean up large volumes of polluted effluents. As a first step, the present work investigated the formation of Fe3O4 by oxidation of Fe(OH)(2) suspension at different conditions, including the initial Fe(OH)(2) suspension concentration, pH value, and temperature. The various mechanisms of the formation of Fe3O4 at different conditions were given based on analysis of the curve in terms of disappearance of Fe(II) phase and the formation of Fe3O4 and the end products during the course of air oxidation. The effect of aging was also discussed. (C) 2004 Elsevier B.V. All rights reserved.

In this work, an attempt was made to enhance gas-liquid mass transfer of oxygen with the aid of colloidal gas aphron (CGA) dispersion. The gas-liquid volume mass transfer coefficients (k(L)a) of oxygen in CGA dispersions were measured and related to stirring velocity, type and concentration of surfactants, and temperature. Four surfactants, sodium dodecyl sulfate (SDS), hexadecyltrimethyl ammonium chloride (HTAC), nonylphenol ethoxylate (NP-10), and potassium mono lauryl phosphate (MAPK), were examined in forming CGAs and thereby affecting the mass transfer of oxygen in the dispersions. It was found that effects of surfactants on the oxygen gas-liquid mass transfer were type-dependent. As concentrations rose, the k(L)a of oxygen increased evidently for SDS and an enhancement of k(L)a by a factor of three was observed at the concentration of 2.75 g/L. However the k(L)a decreased for MAPK. Nonylphenol ethoxylate was found to have little effect on k(L)a and HTAC showed mixed behavior. In SDS dispersion, it was found that the mass transfer reached a maximum value at a stirring velocity of 8000 r/min, but further benefit was not observed afterwards. With the increase of temperature, the mass transfer of oxygen was intensified but no much benefit was observed above 308 K. Published by Elsevier B.V.

Colloidal gas aphrons (CGAs) are finding increasing application in water processing, bioseparation, bubble-entrained floc flotation, separation of oil from sand, etc. This article proposes an effective method of encapsulation to stabilize the CGA bubbles with silicic sol solution for their characterization. The stabilized CGA bubbles can keep shapes and sizes for at least 12 h; even the bubbles smaller than 25 mum can also be stabilized and exist for very long times. Effects of concentration and pH of silicic sol solution on CGA stabilization were studied. Tile optimal ranges of concentration and pH of silicic sol solution are 0.15-0.25 mol/dm(3) and 7-10, respectively. The bubble distortion behavior in disturbance and size distribution of CGAs were examined by using the stabilization method and photographic techniques. (C) 2003 Elsevier Science (USA.). All rights reserved.

Leaching of a copper residue, produced by selective oxidative leaching of a nickel matte, in oxygenated sulfuric acid solution in the presence of chloride ions was investigated. The leaching behaviors of copper and nickel in the copper residue were determined. The effects of chloride addition, oxygen flowrate, sulfuric acid concentration, and temperature were studied as leaching variables. Addition of chloride in small amounts into the leach slurry was found to enhance copper leaching from the residue. (C) 2001 Elsevier Science B.V. All rights reserved.

Clean processing of copper converter slags for reclaiming cobalt and copper could be a challenge. An innovative and environmentally benign approach for recovering metal values from such a slag was developed in the present work. Curing the slag with sulfuric acid, without re-smelting or roasting as currently practiced in the industry, made it amenable to leaching, and more than 95% of the cobalt and up to 90% of the copper was extracted, together with iron, by water leaching, leaving silica behind in a residue. Copper in the leach liquor was recovered by cementation with iron, and the dissolved iron crystallized as ferrous sulfate monohydrate. Cobalt in the pregnant solution rich in iron was recovered by either cementation or sulfide precipitation. Chemical and mineralogical characterization of the slag and its products were examined and compared to determine the nature of the changes occurring during curing and leaching. Operating variables were also investigated and optimized.

As pyrrhotite either dilutes nickel concentrates when recovered or causes significant metals loss and potential environmental harassments if discarded, production of separate pyrrhotite concentrate was thought as a reasonable alternative; however, processing it presents a challenge. A new process was studied to upgrade nickeliferous pyrrhotite concentrates using aqueous pressure oxidation under mild conditions, followed by sulfide precipitation and flotation. The effects of operation parameters such as oxygen pressure, temperature, initial acidity, retention time and concentrate composition were investigated. Pyrrhotite was found to be readily converted into iron oxide. The metal values present in the concentrate, principally nickel and copper, were dissolved in part as pyrrhotite was oxidized, then precipitated from the pulp as sulfides and finally recovered by flotation as a much higher grade concentrate with unreacted sulfide minerals and the produced elemental sulfur together. The pyrrhotite reporting to the leach residue as iron oxide was thus rejected in the flotation tailings.

Aqueous pressure oxidation has been developed to a viable technology. It has found extensive commercial applications in mineral industry. Numerous pressure processing plants have been constructed worldwide for production of nickel, cobalt, copper and zinc from ores, concentrates and other metallurgical intermediates or secondary materials and for pretreatment of gold refractory ores. Successful operation of these plants provides hydrometallurgy with experience and confidence for its potential development and applications. This paper is intended to review the development and applications of pressure oxidation technology and the chemistry involved as well.

Solvent sublation (SS) has been investigated for separating gold from dilute chloride solutions using hexadecyltrimethylammonium bromide (HTMAB) both as collector and surfactant. The composition of organic and aqueous phases, and operating conditions such as gas flowrate and aeration time were studied. As a result, 10% 2-octanol in kerosene with 0.05 M Aliquat 336 was chosen as the organic phase. It is shown that gold can be separated quantitatively from a solution with only 10 ppm Au, with enrichment of 20. Comparisons to ion flotation (IF) and solvent extraction (SX) were also made. SS was found to be more effective than IF. SX is a little more effective than SS, but it takes as long as 24 h for phase disengagement, compared to

A greal deal of effort has been directed towards the development of economically and technically feasible processes for the chemical oxidation of iron sulfides. Such processes applied commercially or under active development, including roasting, and sulfate-, nitrate-, chloride- and alkaline-based aqueous oxidation processes, are outlined in this paper.

Oxidized copper ores are exhibiting increasingly their importance as copper resources as worldwide high grade copper sulfide deposits become depleted. Extensive chemical and technological efforts have been made to meet the demand of exploitation of such copper resources. This paper reviews the processes and modifications developed in the last three decades as the results of these efforts in flotation, hydrometallurgy and combined mineral processing and metallurgy processes. The emphasis is put on the refractory oxidized ores, with a special reference to a copper deposit at Tangdan of Dongchuan mine in Yunnan province of China.

A novel process was developed to apply phase transfer catalysis (PTC) to the sulfidization of the refractory oxidized copper ore which is not amenable to the conventional process of treating oxidized copper ore. Sulfur powder was used to sulfide forming agent in the presence of quaternary ammonium compounds as PT catalyst and kerosene as solvent for sulfur. A sample of refractory oxidized copper ore was treated by this process at 80°C for 2.5 h and recovered by flotation into a concentrate with grade of 12.6% Cu and with 81.5% recovery, which otherwise required the temperature of 180°C and reaction time of 4 h to achieve similar results.

Colloidal emulsion aphrons (CEAs) are considered as the micron-sized water-in-oil (W/O) emulsion-cores encapsulated by a "soapy shell" consisting of multi-layer surfactant molecules. In this dispersion, the emulsion-core sizes are mainly in 10-100 microm and that of the inner phase droplets are in 1-5 microm. CEAs not only behave analogously to emulsion liquid membrane (ELM) in extraction with advantages of high concentration ratio, counter-concentration extraction and combination of extraction with backwash together, but also have the large interface areas, easy scatteration and quick extraction which colloidal liquid aphrons (CLAs) possess. CEA extraction overcomes the restriction of partition equilibrium between the water and the oil phase that CLAs have. They have greater extraction capacity than CLAs. In this study, the application of CEAs to drug overdose treatment was studied using salicylic acid as the model drug, paraffin oil as the membrane phase, PEG-30 dipolyhydroxystearate (P135) as the hydrophobic surfactant, nonylphenol ethoxylate-10 (NP10) as the hydrophilic surfactant and NaOH solution as the receptor phase. Also some factors affecting the stability of this dispersion and extraction ratio were investigated. In order to prepare CEAs successfully, the concentrations of NP10 and P135 should be in 1.5-3.0% (w/v) and 0.25-1.0% (w/v), respectively, together with the ratio of the volume of oil phase to the volume of inner aqueous phase of CEAs, R(oi)> or =1:1. For the extraction of salicylic acid, the pH value of the feed phase was supposed to be lower than 2.0 and the suitable NaOH concentration of the receptor phase was higher than 0.02 mol/L. Under this condition, more than 98.7% of salicylic acid was transported into receptor phase in half a minute.

Chemical and mineralogical characterizations of a copper converter slag, and its products obtained by curing with strong sulphuric acid and leaching with hot water, were carried out using ore microscopy, scanning electronic microscopy with energy dispersive spectrometry, wave-length dispersive X-ray fluorescence spectrometry, X-ray diffractometry and chemical phase analysis, which provided necessary information to develop a new process for treating such slag and further understanding of the chemical and mineralogical changes in the process.