Thermodynamics and the Separation Factor of Dy/U Couple on Ga and Ga–Al Electrodes in Fused LiCl–KCl Eutectic

The dependence of the distribution ratio of the metal on the concentration of hydrochloric of nitric acid was examined for Fe, Co, Ni and Cu extraction with 0.05M solution of dibenzylsulfoxide in toluene. Iron is extracted considerably more than the other metals, and is better extracted from hydrochloric acid than from nitric acid. The separation factor αFe/M (for 8M-HCl) is of the order of 104; this is not sufficient for a separation of trace quantities of iron from Co, Ni and Cu, but even at lower concentrations of HCl (e.g., 5M) the values is high enough for extraction chromatographic separation. The composition of the iron solvate extracted from HCl or LiCl medium was determined to be HFeCl4.2 B (B = dibenzyl sulfoxide).

Download Full-text

Extraction of rare earth metals from trichloroacetate solutions in the presence of linear polyoxonium compounds

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19911585 ◽

1991 ◽

Vol 56 (8) ◽

pp. 1585-1592 ◽

Cited By ~ 2

Author(s):

Petr Vaňura

Keyword(s):

Rare Earth ◽

Nonionic Surfactant ◽

Separation Factor ◽

Rare Earth Metals ◽

Extraction Constants ◽

Distribution Constants ◽

Factor Α

Extraction of rare earth metals from lithium trichloroacetate solutions ( 1.20-2.88 mol l-1) with solutions of the commercial nonionic surfactant Slovafol 909 (p-nonylphenylnonaethylene glycol) in chloroform and dichloromethane was investigated. The extraction constants as well as the Slovafol 909 distribution constants were determined in the water-dichloromethane and water-chloroform systems. The lanthanide distribution ratios decrease with their atomic numbers first rather rapidly (approximately to Sm): the separation factor αSmLa = 1.54 and 1.87 in dichloromethane and in chloroform, respectively; for lanthanides with higher atomic numbers the drop is less pronounced (αLuLa = 2.42 and 2.85 in the two solvents, respectively).

Download Full-text

Enhancing Pervaporation Membrane Selectivity by Incorporating Star Macromolecules Modified with Ionic Liquid for Intensification of Lactic Acid Dehydration

Polymers ◽

10.3390/polym13111811 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1811

Author(s):

Valeriia Rostovtseva ◽

Alexandra Pulyalina ◽

Roman Dubovenko ◽

Ilya Faykov ◽

Kseniya Subbotina ◽

...

Keyword(s):

Ionic Liquid ◽

Lactic Acid ◽

Polymer Matrix ◽

Separation Factor ◽

Membrane Structure ◽

High Performance ◽

Separation Efficiency ◽

Pharmaceutical Chemical ◽

Permeate Flux ◽

Membrane Components

Modification of polymer matrix by hybrid fillers is a promising way to produce membranes with excellent separation efficiency due to variations in membrane structure. High-performance membranes for the pervaporation dehydration were produced by modifying poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) to facilitate lactic acid purification. Ionic liquid (IL), heteroarm star macromolecules (HSM), and their combination (IL:HSM) were employed as additives to the polymer matrix. The composition and structure of hybrid membranes were characterized by X-ray diffraction and FTIR spectroscopy. Scanning electron microscopy was used to investigate the membranes surface and cross-section morphology. It was established that the inclusion of modifiers in the polymer matrix leads to the change of membrane structure. The influence of IL:HSM was also studied via sorption experiments and pervaporation of water‒lactic acid mixtures. Lactic acid is an essential compound in many industries, including food, pharmaceutical, chemical, while the recovering and purifying account for approximately 50% of its production cost. It was found that the membranes selectively remove water from the feed. Quantum mechanical calculations determine the favorable interactions between various membrane components and the liquid mixture. With IL:HSM addition, the separation factor and performance in lactic acid dehydration were improved compared with pure polymer membrane. The best performance was found for (HSM: IL)-PPO/UPM composite membrane, where the permeate flux and the separation factor of about 0.06 kg m−2 h−1 and 749, respectively, were obtained. The research results demonstrated that ionic liquids in combination with star macromolecules for membrane modification could be a promising approach for membrane design.

Download Full-text

Study of separation factor and product extraction ratio in hydrogen isotope separation with displacement chromatography

Fusion Engineering and Design ◽

10.1016/j.fusengdes.2021.112246 ◽

2021 ◽

Vol 165 ◽

pp. 112246

Author(s):

Yuting Liu ◽

Wenqing Wu ◽

Guanghui Zhang ◽

Manquan Fang ◽

Wenyong Jing ◽

...

Keyword(s):

Separation Factor ◽

Hydrogen Isotope ◽

Isotope Separation ◽

Extraction Ratio ◽

Displacement Chromatography

Download Full-text

Separation of Methane from Shuttle Tanker Vents Gases by Adsorption on a Polyurethane/Zeolite Membrane

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.733.42 ◽

2017 ◽

Vol 733 ◽

pp. 42-46

Author(s):

Habiba Shehu ◽

Edidiong Okon ◽

Edward Gobina

Keyword(s):

Carbon Dioxide ◽

Physical Properties ◽

Crude Oil ◽

Deep Water ◽

Separation Factor ◽

Gas Permeation ◽

Zeolite Membrane ◽

Alumina Support ◽

Molar Flux

Shuttle tankers are becoming more widely used in deep water installations as a means of transporting crude oil to storage plants and refineries. The emissions of hydrocarbon vapours arise mainly during loading and offloading operations. Experiments have been carried out on the use of polyurethane/zeolite membrane on an alumina support for the separation of methane from carbon dioxide and oxygen. The physical properties of the membrane were investigated by FTIR. Single gas permeation tests with methane, propane, oxygen and carbon dioxide at a temperature of 293 K and pressure ranging from 0.1 to 1.0 x 10-5 Pa were carried out. The molar flux of the gases through the membrane was in the range of 3 x 10-2 to 1 x 10-1 molm-2s-1. The highest separation factor of CH4/CO2 and CH4/O2 and CH4/C3H8 was determined to be 1.7, 1.7 and 1.6 respectively.

Download Full-text

Metal–organic frameworks (MOFs) as highly efficient agents for boron removal and boron isotope separation

RSC Advances ◽

10.1039/c6ra26588j ◽

2017 ◽

Vol 7 (26) ◽

pp. 16022-16026 ◽

Cited By ~ 6

Author(s):

Jiafei Lyu ◽

Hongxu Liu ◽

Jingshuang Zhang ◽

Zhouliangzi Zeng ◽

Peng Bai ◽

...

Keyword(s):

Separation Factor ◽

Isotope Separation ◽

Metal Organic Frameworks ◽

Boron Isotope ◽

Boron Removal ◽

Boron Uptake ◽

Highly Efficient ◽

Metal Organic ◽

High Boron

A variety of MOFs were observed with ZIF-8, to our knowledge, showing the highest boron uptake and MIL-101(Cr) with an unprecedentedly high boron isotope separation factor.

Download Full-text

Separation of Dimethylformamide/H2O Mixtures Using Pervaporation-Distillation Hybrid Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.233-235.866 ◽

2011 ◽

Vol 233-235 ◽

pp. 866-869 ◽

Cited By ~ 1

Author(s):

Guang Lu Han ◽

Qi Zhang ◽

Jing Zhong ◽

Hui Shao ◽

Huan Ru Zhang

Keyword(s):

Aqueous Solution ◽

Separation Factor ◽

Aspen Plus ◽

Composite Membranes ◽

Hybrid Process ◽

Hybrid Processes ◽

Operation Temperature ◽

The Cost

Three kinds of commercial PVA composite membranes with different crosslinking degrees (PVA-1, PVA-2 and PVA-3) were used to separate DMF/H2O mixtures. Their pervaporation performance was investigated at different operation temperatures. The results showed that PVA-1 was the most suitable one for separating DMF/H2O mixtures. When operation temperature was 60°C and downstream pressure was lower than 6kPa, flux reached to 0.59 kg·m-2·h-1 and separation factor was 33 for PVA-1 membranes. Aspen Plus® was applied to simulate the normal distillation for retentate from pervaporation unit. Comparing with the two-effect distillation, the cost of concentrating DMF could be reduced 16.2% to 19.2% for DMF aqueous solution with different composition by hybrid processes. The cost would be the lowest for a hybrid process that concentrated the feed into 50wt% by pervaporation firstly, then concentrated retentate to 99.6wt% by two-effect distillation

Download Full-text

Untersuchung von Calciumisotopieeffekten bei heterogenen Austauschgleichgewichten / Investigation of Isotopic Effects of Calcium in Heterogeneous Exchange Equilibria

Zeitschrift für Naturforschung B ◽

10.1515/znb-1972-0204 ◽

1972 ◽

Vol 27 (2) ◽

pp. 126-133 ◽

Cited By ~ 33

Author(s):

Klaus Gustav Heumann ◽

Karl Heinrich Lieser

Keyword(s):

Separation Factor ◽

Calcium Concentration ◽

Isotopic Fractionation ◽

Ion Source ◽

Isotopic Effect ◽

Mass Unit ◽

Calcium Isotopes ◽

Heterogeneous Exchange ◽

Loaded Column ◽

Isotopic Effects

The following heterogeneous exchange equilibria have been examined for isotopic effects: CaCO3/Ca(aq.)2⊕. Ca-GBHA/Ca(aq.)2⊕ and Ca(Dowex 50)2⊕/Ca(aq.)2⊕ (GBHA = glyoxal-bis (2-hydroxyanil)). The isotopic ratios 44Ca/40Ca and 48Ca/40Ca were determined by means of a mass spectrometer with a thermal ion source. In the system CaCO3/Ca(aq.)2⊕, the elementary separation factor was found to be less than 1‰ or 0,5‰ per mass unit, respectively.For the exchange in the system Ca-GBHA/Ca(aq.)2⊕ in the concentration range from 0.011 to 0.84 M an elementary separation factor less than 1‰ per mass unit was found; from a three-stage experiment at a calcium concentration of 1.23 M it was concluded that the elementary isotopic effect is less than 0.4‰ per mass unit. Therefore no isotopic fractionation is to be expected for precipitation of inorganic or organic calcium salts.An enrichment of the heavier calcium isotopes in the solution was found in the case of the exchange in a Dowex 50-X12 loaded column. The isotopic effect depends on the concentration of the hydrochloric acid used as the eluent.

Download Full-text

Dehydration of water/pyridine mixtures by pervaporation using cellulose acetate/ polyacrylonitrile blend membrane

Water Science & Technology ◽

10.2166/wst.2011.337 ◽

2011 ◽

Vol 63 (8) ◽

pp. 1695-1700 ◽

Cited By ~ 3

Author(s):

J. H. Lv ◽

G. M. Xiao

Keyword(s):

Cellulose Acetate ◽

Separation Factor ◽

Experimental Results ◽

Separation Performance ◽

Permeation Flux ◽

Feed Concentration ◽

Blend Membrane ◽

Pyridine Solution ◽

Operation Temperature

Cellulose acetate/ polyacrylonitrile (CA/PAN) membranes were prepared and used to separate pyridine / water mixtures by pervaporation. The membranes were characterized through SEM. The effects of feed concentration, operation temperature and downstream pressure on the separation performance were evaluated. Experimental results indicated the increase of operation temperature could raise the permeation flux and the separation factor, while increasing feed concentration and downstream pressure would raise the separation factor and decrease the permeation flux. Under the conditions that pyridine solution was 99 wt.%, operation temperature was 323 K and downstream pressure was 20 mmHg, the CA/PAN blend membrane showed its best separation performance that the permeation flux was 56 · g · m−2 h−1 and the separation factor was 182.

Download Full-text

Ein Wasserstoffisotopieeffekt im CuSO4 * 5H2O

Zeitschrift für Naturforschung A ◽

10.1515/zna-1969-1007 ◽

1969 ◽

Vol 24 (10) ◽

pp. 1502-1511

Author(s):

Karl Heinzinger

Keyword(s):

Water Vapor ◽

Aqueous Solutions ◽

Separation Factor ◽

Room Temperature ◽

Copper Ion ◽

Hydrogen Isotopes ◽

Bulk Water ◽

Water Molecules ◽

Hydration Water ◽

Sulfate Solutions

Abstract There are two kinds of water in CuSO4·5H2O differing by their binding in the crystal. The oxygen of four water molecules is bonded to the copper ion, that of the fifth molecule is hydrogen bonded. It is shown that the D/H ratios of these two kinds of water differ by 5.7%, the light isotope being enriched in the water molecules coordinated with the copper ion. The results show that there is no exchange of the hydrogen isotopes during the time needed for dehydration at room temperature which takes several days. The assumption has been confirmed that the water coordinated with the copper ion leaves the crystal first on dehydration at temperatures below 50 °C. Additional measurements of the separation factor for the hydrogen isotopes between water vapor and copper sulfate solutions allow conclusions on the fractionation of the hydrogen isotopes between bulk water and hydration water in aqueous solutions.

Download Full-text