scholarly journals Separation and Recovery of Gold(III), Palladium(II) and Platinum(IV) by Solvent Extraction Using a New β-Diketone Derivative from Acidic Solutions

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4436
Author(s):  
Elzbieta Radzyminska-Lenarcik ◽  
Ilona Pyszka ◽  
Artur Kosciuszko
Keyword(s):  
Solvent Extraction ◽  
Aqueous Phase ◽  
Acidic Medium ◽  
Methylene Chloride ◽  
Separation Efficiency ◽  
Ammonium Thiocyanate ◽  
Mineral Acid ◽  
Chloride System ◽  
Hcl Concentration ◽  
The Impact

This study indicates that a new amine derivative of β-diketone (EDAB-acac) can be successfully used in an acidic medium (HCl) to separate a mixture containing Au(III), Pd(II), and Pt(IV) ions using solvent extraction. The study was conducted in single and ternary model solutions. The impact of acid concentration and the type of solvent (toluene, chloroform, methylene chloride, 2-ethylhexanol) on separation efficiency was discussed. It has been shown that increasing the HCl concentration in the aqueous phase does not favor extraction. In contrast, solvents with high donor numbers (methylene chloride, 2-ethylhexanol) increase both the extraction percentage of Pd and Au as well as the separation coefficients of Pd in relation to Au and Pt. The palladium(II) and gold(III) (which form 4-coordinated planar [MCl4]2− complexes) are extracted most efficiently, Pd(II) (87–93%) and Au(III) (56–62%). The stripping of Au(III), Pd(II), and Pt(IV) ions from the EDAB-acac-methylene chloride phase was also investigated using 0.5 M ammonia aq., mineral acid (5 M HCl, 5 M HNO3), 0.1 M thiourea in HCl and 0.5 M ammonium thiocyanate. A 3-step stripping process was proposed for the recovery of Pd(II), Au(III), and Pt(IV) from the Pd-Au-Pt mixture in the EDAB-acac-methylene chloride system. In the first stage, the aqueous phase is treated with 5 M HNO3 (Pt separation), followed by the application of 0.5 M ammonia (Pd separation) and, finally, 0.1 M thiourea in HCl (Au separation). The solvent extraction with EDAB-acac in acidic medium (HCl) can be used for separation of Pd(II) and Au(III) ions from e-waste leach solutions.

Comparison of Sorption and Extraction Methods for Recovery of Trace Organics from Water

1983 ◽  
Vol 15 (6-7) ◽  
pp. 149-159 ◽  
Author(s):  
V C Blok ◽  
G P Slater ◽  
E M Giblin
Keyword(s):  
Solvent Extraction ◽  
Methylene Chloride ◽  
Extraction Methods ◽  
Liquid Extraction ◽  
Standard Mixture ◽  
Liquid Liquid Extraction ◽  
Trace Organics ◽  
Tenax Gc

Several commercially available adsorbents were compared with solvent extraction methods for their utility in recovering trace organics from water. The adsorbents examined included Amberlite XAD-2, XAD-4 and XAD-8, Ambersorb XE340 and XE348 and Tenax-GC. All were found to produce high artifact levels, even after extensive clean-up, making them unsuitable for the analysis of trace organics in water. Quantitatively, Likens-Nickerson or continuous liquid-liquid extraction with méthylene chloride gave better recoveries than the adsorbents. Qualitatively, extractive methods were preferred as they yielded much lower levels of impurities than the adsorbents. These methods of recovering trace organics were evaluated using a standard mixture of compounds added to the water at a level of 55 µg/l. Likens-Nickerson extraction gave comparable recoveries of this mixture at 55 µg/l and 11 µg/l.

The Impact of the Aqueous Phase Chemistry of HNO4 on Gas Phase Tropospheric Chemistry

2001 ◽  
Vol 32 ◽  
pp. 269-270
Author(s):  
J.E. WILLIAMS ◽  
F.J. DENTENER ◽  
A.R. van den BERG
Keyword(s):  
Gas Phase ◽  
Aqueous Phase ◽  
Tropospheric Chemistry ◽  
Phase Chemistry ◽  
The Impact

scholarly journals Impact of Nanoparticle Consolidation on Charge Separation Efficiency in Anatase TiO2 Films

2021 ◽  
Vol 9 ◽  
Author(s):  
Karin Rettenmaier ◽  
Thomas Berger
Keyword(s):  
Thermal Annealing ◽  
Charge Separation ◽  
Separation Efficiency ◽  
Internal Surface ◽  
Processing Temperature ◽  
Cyclic Voltammograms ◽  
Internal Surface Area ◽  
Deep Traps ◽  
Charge Separation Efficiency ◽  
The Impact

Mesoporous films and electrodes were prepared from aqueous slurries of isolated anatase TiO2 nanoparticles. The resulting layers were annealed in air at temperatures 100°C ≤ T ≤ 450°C upon preservation of internal surface area, crystallite size and particle size. The impact of processing temperature on charge separation efficiency in nanoparticle electrodes was tracked via photocurrent measurements in the presence of methanol as a hole acceptor. Thermal annealing leads to an increase of the saturated photocurrent and thus of the charge separation efficiency at positive potentials. Furthermore, a shift of capacitive peaks in the cyclic voltammograms of the nanoparticle electrodes points to the modification of the energy of deep traps. Population of these traps triggers recombination possibly due to the action of local electrostatic fields attracting photogenerated holes. Consequently, photocurrents saturate at potentials, at which deep traps are mostly depopulated. Charge separation efficiency was furthermore investigated for nanoparticle films and was tracked via the decomposition of hydrogen peroxide. Our observations evidence an increase of charge separation efficiency upon thermal annealing. The effect of particle consolidation, which we associate with minute atomic rearrangements at particle/particle contacts, is attributed to the energetic modification of deep traps and corresponding modifications of charge transport and recombination, respectively.

scholarly journals Aspergillus piperis A/5 from plum-distilling waste compost produces a complex of antifungal metabolites active against the phytopathogen Pythium aphanidermatum

2016 ◽  
Vol 68 (2) ◽  
pp. 279-289 ◽  
Author(s):  
Jelena Jovicic-Petrovic ◽  
Sanja Jeremic ◽  
Ivan Vuckovic ◽  
Sandra Vojnovic ◽  
Aleksandra Bulajic ◽  
...  
Keyword(s):  
Citric Acid ◽  
Solvent Extraction ◽  
Antifungal Activity ◽  
Aqueous Phase ◽  
Plant Pathogens ◽  
Complex Mixture ◽  
Pythium Aphanidermatum ◽  
Disease Suppression ◽  
Antifungal Metabolites ◽  
Culture Extract

Adding compost to soil can result in plant disease suppression through the mechanisms of antagonistic action of compost microflora against plant pathogens. The aim of the study was to select effective antagonists of Pythium aphanidermatum from compost, to assess the effect of its extracellular metabolites on the plant pathogen, and to characterize antifungal metabolites. The fungal isolate selected by a confrontation test was identified as Aspergillus piperis A/5 on the basis of morphological features and the internal transcribed spacer (ITS) region, ?-tubulin and calmodulin partial sequences. Liquid chromatography-mass spectroscopy (LC-MS) analysis showed that gluconic and citric acid were the most abundant in the organic culture extract. However, the main antifungal activity was contained in the aqueous phase remaining after the organic solvent extraction. The presence of considerable amounts of proteins in both the crude culture extract as well as the aqueous phase remaining after solvent extraction was confirmed by SDS-PAGE. Isolated Aspergillus piperis A/5 exhibits strong antifungal activity against the phytopathogen Pythium aphanidermatum. It secretes a complex mixture of metabolites consisting of small molecules, including gluconic acid, citric acid and itaconic acid derivatives, but the most potent antifungal activity was associated with proteins resistant to heat and organic solvents. Our findings about the activity and characterization of antagonistic strain metabolites contribute to the understanding of the mechanism of interaction of antifungal metabolites as well as fungal-fungal interaction. The obtained results provide a basis for further application development in agriculture and food processing.

scholarly journals Modeling the Separation of Microorganisms in Bioprocesses by Flotation

2018 ◽  
Author(s):  
Stefan Schmideder ◽  
Christoph Kirse ◽  
Julia Hofinger ◽  
Sascha Rollié ◽  
Heiko Briesen
Keyword(s):  
Fluid Dynamics ◽  
Separation Efficiency ◽  
Algebraic Model ◽  
Balance Model ◽  
Separation Processes ◽  
Dissolved Air Flotation ◽  
Computational Fluid Dynamics Cfd ◽  
Cell Size Distributions ◽  
Fermentation Broths ◽  
The Impact

Bioprocesses for the production of renewable energies and materials lack efficient separation processes for the utilized microorganisms such as algae and yeasts. Dissolved air flotation (DAF) and microflotation are promising approaches to overcome this problem. The efficiency of these processes depends on the ability of microorganisms to aggregate with microbubbles in the flotation tank. In this study, different new or adapted aggregation models for microbubbles and microorganisms are compared and investigated for their range of suitability to predict the separation efficiency of microorganisms from fermentation broths. The complexity of the heteroaggregation models range from an algebraic model to a 2D population balance model (PBM) including the formation of clusters containing several bubbles and microorganisms. The effect of bubble and cell size distributions on the flotation efficiency is considered by applying PBMs, as well. To determine the impact of the model assumptions, the modeling approaches are compared and classified for their range of applicability. Evaluating computational fluid dynamics (CFD) of a DAF system shows the heterogeneity of the fluid dynamics in the flotation tank. Since analysis of the streamlines of the tank show negligible backmixing, the proposed aggregation models are coupled to the CFD data by applying a Lagrangian approach.

Catalytic conversion of biomass derivatives to lactic acid with increased selectivity in an aqueous tin(ii) chloride/choline chloride system

2018 ◽  
Vol 20 (17) ◽  
pp. 4112-4119 ◽  
Author(s):  
Asep Bayu ◽  
Akihiro Yoshida ◽  
Surachai Karnjanakom ◽  
Katsuki Kusakabe ◽  
Xiaogang Hao ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Lactic Acid ◽  
Aqueous Phase ◽  
Choline Chloride ◽  
Reaction System ◽  
Catalytic Conversion ◽  
Phase Reaction ◽  
Chloride System ◽  
System P

The catalytic activity and selectivity of SnCl2 for the conversion of biomass derivatives into LacA in the aqueous phase reaction system was found to be increased by the addition of choline chloride.

LTCC 3D FLOW FOCALIZATION DEVICE FOR LIQUID-LIQUID PARTIAL SOLVENT EXTRACTION

2016 ◽  
Vol 2016 (CICMT) ◽  
pp. 000111-000117
Author(s):  
Houari Cobas Gomez ◽  
Jéssica Gonçalves da Silva ◽  
Jocasta Mileski Machado ◽  
Bianca Oliveira Agio ◽  
Francisco Jorge Soares de Oliveira ◽  
...  
Keyword(s):  
Solvent Extraction ◽  
Aqueous Phase ◽  
Microfluidic Device ◽  
Flow Rate ◽  
Extraction Efficiency ◽  
Channel Length ◽  
Main Channel ◽  
Process Variables ◽  
3D Flow ◽  
Acetone Concentration

Abstract The present work shows a ceramics microfluidic device for partial solvent extraction scheme. The technology used for device fabrication was Low Temperature Cofired Ceramics (LTCC) which allows us for complex and chemical resistant 3D microfluidic devices. The proposed system aims to partially extract the solvent present in a mixture containing aqueous and organic phases. This scheme uses a 3D flow focalization in order to improve the solvent diffusion into the external aqueous phase. The device is composed by three different parts, the input channels distribution, the main channel and the output channels distribution. The designed input channels distribution ensures a centered 3D focalized solvent stream along the main channel. The focalized solvent mixes with the surrounding water thanks to diffusion. Projected output channels take the central fluid out separately from the surrounding. Thus the device has two different outputs, one for the focalized fluid and another one for the waste fluid, which is the aqueous phase plus solvent. For a device concept proof, acetone and water were used as organic and aqueous phases, respectively. COMSOL Multiphysics was used for device microfluidics and chemical transport simulation. The extraction efficiency was the variable used as indicator for device performance validation. The flow rate ratio between phases, total flow rate, main channel length and focalized stream channel output hydraulic diameter (ODH) were used as process variables for simulation purposes. A factorial experimental planning was used in order to analyze the extraction efficiency taking into account process variables effects. From simulation results it was determined main channel length and ODH as the variables with stronger effect on extraction efficiency. Obtained simulated efficiencies were as high as 80.6%. Considering previous results observations a microfluidic device was fabricated with a main channel length of 21,4 mm and ODH of 214,63 μm. Gas chromatography was used to measured acetone concentration in outputs samples and from here the extraction efficiency. Experimental results were in agreement with simulation, returning extraction efficiencies in the order of 80.8% ± 2.2%.

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