High Distribution Coefficient Research Articles

Fast Search of Dangerous Lines in Power Flow Transferring in Power System

A method for fast search of dangerous lines in power flow transferring was put forward. Search the equal-phase parallel lines of the overload line by graph theory and voltage phasor angle. Search the shortest path between the end nodes of the overload line which went through the equal-phase parallel lines. The lines on the paths belonged to the power flow transferring line set, where the lines with high active power flow distribution coefficient were dangerous lines in power flow transferring. The method is more targeted in the search for power flow transferring path. It will not leave out dangerous lines for only looking for the shortest line between the two nodes of the overload line, and it wil not select the redundant lines for searching the K shortest paths between the two nodes of the overload line. This method is simple and accurate with little calculation. The method is verified by simulation analysis based on IEEE 39 and IEEE 118 bus system.

Separation of Penicillin G from Fermentation Broth Using N,N-Dioctyloctan-1-amine Extractant in Different Diluents

The extraction of penicillin G was investigated using N,N-Dioctyloctan-1-amine (TOA) with different diluents having distinct functional groups. Nine diluents were used in the study, namely, octan-1-ol, nonan-1-ol, isoamyl alcohol, ethyl ethanoate, propyl ethanoate, methyl iso butyl ketone(MIBK), octan-2-one, octane, and decane. The measurements were performed at a temperature of 298.2 K. The experimental results of batch extractions were used to calculate distribution coefficients (KD), loading factors (Z), and extraction efficiency (E). The highest distribution coefficient (KD = 5.79) was obtained with isoamyl alcohol, and its extraction efficiency was 85.27%. Further, the highest loading factor was reached to a value of 0.130 at 0.374 mol.kg−1 amine concentration. Overloading was not observed at any amine concentration. Solvatochromic model (Linear solvation Energy Relationship (LSER)) for data which obtained from alcohols experiments gives the good results as near as same to experimental results. Suitability of data between experiments and model predictions have been tested with root main square deviation (RMSD) with 0.99.

Sorption properties of nanostructured potassium aluminosilicate

The ability of synthetic nanostructured potassium aluminosilicate (PAS) KAlSi3O8·1.5H2O with the specific surface area of 105 ± 5 m2 g−1 to take up cesium ions was studied. The maximal sorption capacity of PAS in sorption of Cs+ ions from cesium carbonate solutions containing no other salts is ∼3.7 mmol g−1. In Cs+ sorption from solutions containing no other salts, the sorption capacity is the lowest at pH 1; it increases with pH, reaching a maximum at pH 10.8. The effect of salt background (various concentrations and ratios of KCl and NaCl) on the sorption properties of PAS was examined. The sorption capacity decreases to the greatest extent (to 0.25 mmol g−1) in solutions containing the K+ and Na+ ions simultaneously at concentrations of 68 and 517 mM, respectively. The dependence of the cesium sorption on the concentration of nitrates (NaNO3, KNO3, NH4NO3) and the kinetics of the cesium sorption from aqueous NaNO3 solution were studied with the 137Cs tracer. The highest distribution coefficients (up to 12000 mL g−1) are observed in 137Cs sorption from NaNO3 solutions. The degree of the 137Cs sorption reaches a maximum (92 ± 4%) in sorption from 0.01 M NaNO3 solutions at the sorption time of 4 h.

Anion exchange cycle of catalyst in liquid–liquid phase-transfer catalysis reaction: Novel autocatalysis

Abstract Novel autocatalytic process under liquid–liquid phase-transfer catalysis (LL-PTC) condition was found, which was induced by the anion exchange of catalyst. Induction period existed in Horner–Wadsworth–Emmons reaction under LL-PTC conditions and was not caused by the equilibrium of reactants or the saturation of the intermediate. Introduction of the more hydrophilic anion to PTC system could increase the initial reaction rate and decrease the induction time, especially for diethyl phosphate anion (another product of the bond-forming reaction, PO−). Furthermore, the generation of ion-pair (PTC+PO−) in the biphasic system was certified by extraction experiments. PTC+PO− showed a higher catalytic activity (more than 2-fold) and a higher distribution coefficient from the interfacial region to the organic phase (2.7-fold) than the initial catalyst. Accordingly, the interfacial mechanism including the instinct catalytic cycle and the autocatalytic cycle was proposed, which were induced by the initial catalyst and PTC+PO−, respectively. Subsequently the dependence of instinct catalytic activity and autocatalytic activity on reaction parameters was compared.

Carbamoylalkylphosphonates for Dramatic Enhancement of Uranium Extraction from Phosphates Ores

We describe here the full synthesis of a novel family of bifunctional ligands and present a complete study of their extraction properties in regards to an aqueous phosphoric acid solution containing uranium. We developed a high yielding synthesis of amido phosphonate ligands and focused our investigation on the effect of steric hindrance on the methylene bridge between the two functions. These new bifunctional ligands were found to extract selectively hexavalent uranium U(VI) with high distribution coefficient (D) and selectivity towards iron Fe (III) in 5 M phosphoric acid solution. From a structure-activity approach a specific ligand called DEHCNPB has been put forward in regard to the outstanding results obtained for the selective extraction, and quantitative recovery of uranium compared to the URPHOS reference system.

Liquid–Liquid Equilibria for the Systems: Heptane + Benzene + Solvent (Propylene carbonate, N,N-Dimethylformamide, or Mixtures) at Temperatures from (303.2 to 323.2) K

The extraction of benzene from heptane by the solvents such as N,N-dimethylformamide (DMF), propylene carbonate, and complex solvent (DMF + propylene carbonate) were researched. The liquid–liquid equilibrium (LLE) data were experimentally obtained for the ternary systems heptane + benzene + DMF and heptane + benzene + propylene carbonate at 313.2 K and atmospheric pressure and for the quaternary systems heptane + benzene + DMF + propylene carbonate at (303.2, 313.2, and 323.2) K and atmospheric pressure. The nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) models were used to correlate the LLE data satisfactorily, and the selectivity and distribution coefficients of benzene were calculated. Due to its high selectivity and suitable distribution coefficient, DMF + propylene carbonate can be used as a potential extracting solvent to separate benzene from heptane.

Polyethylenimine-Assisted Extraction of α-Tocopherol from Tocopherol Homologues and CO2-Triggered Fast Recovery of the Extractant

The separation of natural homologues provides a great challenge due to high similarities of their structures and properties. In this work, the use of the polymeric extractant polyethylenimine (PEI) for the separation of α-tocopherol from the tocopherol homologues was investigated. Various PEI–cosolvent solutions were used to extract tocopherols from their hexane solutions. The effects of PEI molecular weight, cosolvent type, and PEI–cosolvent composition were systematically studied. High distribution and selectivity coefficients of tocopherols were obtained with PEI–acrylonitrile (ACN) as the extractant. A clear advantage of PEI extractant is its stimuli-responsive property triggered by CO2. PEI–extracted tocopherols could be replaced and released from PEI chains with CO2 bubbling, with PEI–CO2 precipitated out from the extract phase, which greatly facilitates the back extraction of tocopherols and the recovery of PEI for reuse. With CO2 bubbling, it took only three back extractions to recover over 90% tocopherols, compared with 12 in theory without CO2 treatment. Precipitated PEI–CO2 could be redissolved in cosolvent for reuse by N2 bubbling and heating. The distribution coefficients decreased by approximately 10% after being recycled three times.

Distribution of dopant metals between PbTiO3 crystals and PbO-B2O3 flux

Single crystals of lead titanate PbTiO3 doped with silicon, calcium, chromium, manganese, cobalt, nickel, copper, zinc, and cadmium were grown. The compositions and crystallographic parameters of the crystals were studied. The lowest distribution coefficients of dopants between PbTiO3 crystals and flux were observed with Mn +2 and Co +2 and the highest, with Ca +2 . Doping with niobium leads to the formation of solid solutions with the pyrochlore structure A2B2O7 and even higher distribution coefficient. A correlation was found between dopant concentrations and crystal cell parameters.

Fate of atrazine in a soil under different agronomic management practices

Agricultural management affects the movement of atrazine in soil and leaching to groundwater. The objective of this study was to determine atrazine adsorption in a soil after 20 years of atrazine application under agronomic management practices differing in tillage practice (conventional and zero tillage), residue management (with and without residue retention) and crop rotation (wheat-maize rotation and maize monoculture). Atrazine sorption was determined using batch and column experiments. In the batch experiment, the highest distribution coefficient Kd (1.1 L kg−1) at 0–10 cm soil depth was observed under zero tillage, crop rotation and residue retention (conservation agriculture). The key factor in adsorption was soil organic matter content and type. This was confirmed in the column experiment, in which the highest Kd values were observed in treatments with residue retention, under either zero or conventional tillage (0.81 and 0.68 L kg−1, respectively). Under zero tillage, the fact that there was no soil movement helped to increase the Kd. The increased soil organic matter content with conservation agriculture may be more important than preferential flow due to higher pore connectivity in the same system. The soil's capacity to adsorb 2-hydroxyatrazine (HA), an important atrazine metabolite, was more important than its capacity to adsorb atrazine, and was similar under all four management practices (Kd ranged from 30 to 40 L kg−1). The HA adsorption was attributed to the type and amount of clay in the soil, which is unaffected by agronomic management. Soils under conservation agriculture had higher atrazine retention potential than soils under conventional tillage, the system that predominates in the study area.

Effect of the cation and anion of the ionic liquid on desulfurization of model fuels

Ionic liquids (ILs) are known as a new solvents with high extraction capacity for aromatic sulfur and aromatic compounds from gasoline and diesel in comparison to the conventional solvents. In this work the desulfurization ability of 21 ionic liquids in the extraction of sulfur organic compounds from hydrocarbons, which were used as a model of gasoline and diesel oils by solvent extraction, has been developed. With this aim, ternary liquid–liquid phase equilibrium data (LLE) has been obtained for mixtures of {IL+model fuel (thiophene, benzothiophene, dibenzothiophene, toluene, tetralin)+heptane} at T=298.15K and ambient pressure. The ILs studied: pyridinium-, pyrrolidinium-, morpholinium-, imidazolium-, piperidinium-, phosphonium-, and ammonium-based with different anions as dicyanoamide, [DCA], tetracyanoborate, [TCB], tricyanomethanide, [TCM], bis{(trifluoromethyl)sulfonyl}imide, [NTf2], trifluorotris(perfluoroethyl)-phosphate, [FAP], trifluoroacetate, [TFA], and trifluoromethanesulfonate, [CF3SO3]. The suitability of ILs used as solvents for extractive desulfurization has been evaluated in terms of solute distribution coefficient and selectivity. Few of proposed ILs, as 1-butyl-4-methylpyridinium dicyanamide, [bmPY][DCA], 1-butyl-1-methylpyrrolidinium dicyanamide, [bmPYR][[DCA], and N-butyl-N-methylmorpholinium tricyanomethanide, [bmMOR][TCM] show high selectivities (>200) and high distribution coefficients (>1.2) for extraction of sulfur compounds. The experimental results obtained in this work are evaluated in view of the results reported in literature [1,2]. It is shown that the ionic liquids investigated in this work are able to extract sulfur in preference to toluene and tetralin. Moreover, the distribution coefficients for [bmPYR][TCM], [bmIM][TCM] and [bmPYR][TCB] ILs are the best for the extraction of thiophene, the [bmPY][DCA], [bmPYR][TCB], [bmPYR][TCM] and [bmIM][TCM] ILs have the best distribution coefficients for benzothiophene; the [bmPY][DCA], [bmPYR][TCM] and [P6,6,6,14][TCM] ILs have the best distribution coefficients for dibenzothiophene.

Pentacyanoferrate(II) complexes with N-containing derivatives of chitosan and polyallylamine: Synthesis and cesium uptake properties

Here we report on synthesis of new organic–inorganic materials based on products of interaction between sodium aminoprusside and polymer ligands (chitosan (CS), N-2-(2-pyridyl)ethylchitosan (2-PC), N-2-(4-pyridyl)ethylchitosan (4-PC), N-(4-methyl-5-imidazolyl)methylchitosan (IC), N-(2-cyanoethyl)chitosan (CC), polyallylamine (PA), N-(2-pyridyl)methyl-polyallylamine (PMPA), N-2-(2-pyridyl)ethyl-polyallylamine (PEPA), N-(4-methyl-5-imidazolyl)methyl-polyallylamine (IPA) and poly(2-vinylpyridine) (PVP)). The composition of the obtained materials was characterized using the element analysis and X-ray diffraction; the Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis data were used to propose the structure of the formed complexes. It was established that ion and ligand exchange were the main reactions, through which sodium aminoprusside interacts with water-soluble polymer salts. Reactivity in complex formation reaction of unmodified polymers changes in a row: PA>CS>PVP. Modification of chitosan with 2-(4-pyridyl)ethyl and 2-cyanoethyl moieties enhances reactivity of chitosan to the level of PA, while introduction of 2-(2-pyridyl) and (4-methyl-5-imidazolyl)methyl moieties, on the contrary, decreases reactivity of chitosan to that of PVP. At the same time, functionalization of PA with 2-pyridylalkyl groups decreases its reactivity in reaction with aminoprusside ion. Thus, reactivity of all studied polymeric matrices changes in the row: PA≈4-PC≈CC>CS>2-PC≈IPA≈IC>PMPA>PVP>PEPA. The distribution coefficients with respect to cesium ions have been determined for the synthesized complexes in cobalt(II) form. It has been shown that the complex of chitosan with pentacyanoferrate(II) has higher distribution coefficient with respect to Cs+ ions, as compared to its N-derivatives and synthetic polymers. Organic–inorganic materials obtained in the matrix of synthetic polymers have shown higher tendency to peptization and, therefore, lower sorption capacities and distribution coefficients.

Preparation and Properties of Novel Nano-Cu-Vermiculite Composite for Iodineion Extraction in the Phosphoric Acid

Nano-Cu-vermiculite composite with high distribution coefficients and adsorption capacity towards iodine ion in phosphoric acid systemwere prepared. This material was prepared by loading organic and copper salts with an ion exchange method on vermiculite substrate. Adsorption kinetic and role of phosphoric acid was discussed. Adsorption kinetic experiments indicated that more than 90% of the iodine was absorbed by the composite within the first 30 min and the adsorption kinetic fitted the pseudo-second-order model well. Phosphoric acid has little effect on the extraction, which provides a theoretical basis for the extraction of iodine in the wet-process phosphoric acid. Various characterization methods including SEM, and TG/DTA were utilized for the evaluation of nano-Cu-vermiculite composite. The interlayer spacing increased after CTAB and copper were inserted in vermiculite, and the size of sphere nanocopper in the range of 50-100 nm distribute on the surface and in the interlayer. Therefore the nano-Cu-vermiculite adsorbent has a promising application in iodine extraction from the wet-process phosphoric acid.

Selective removal of cesium from aqueous solutions with nickel (II) hexacyanoferrate (III) functionalized agricultural residue–walnut shell

A novel nickel (II) hexacyanoferrate (III) functionalized agricultural residue-walnut shell (NiIIHCFIII-WS) was developed to selectively remove cesium ion (Cs+) from aqueous solutions. This paper showed the first integral study on Cs+ removal behavior and waste reduction analysis by using biomass adsorption material. The results indicated that the removal process was rapid and reached saturation within 2h. As a special characteristic of NiIIHCFIII-WS, acidic condition was preferred for Cs+ removal, which was useful for extending the application scope of the prepared biomass material in treating acidic radioactive liquid waste. The newly developed NiIIHCFIII-WS could selectively remove Cs+ though the coexisting ions (Na+ and K+ in this study) exhibited negative effects. In addition, approximately 99.8% (in volume) of the liquid waste was reduced by using NiIIHCFIII-WS and furthermore 91.9% (in volume) of the spent biomass material (Cs-NiIIHCFIII-WS) was reduced after incineration (at 500°C for 2h). Due to its relatively high distribution coefficient and significant volume reduction, NiIIHCFIII-WS is expected to be a promising material for Cs+ removal in practice.

English

COSMO-RS method was used in screening 2106 ionic liquids as alternate solvents to volatile n-dodecane used in PUREX. The distribution coefficients of uranylnitrate in ionic liquids/aqueous nitric acid biphasic system and the solubility of the ionic liquids in water were determined using COSMO-RS. Seventeen ionic liquids based on tetrafluoroborate BF4, were the most hydrophobic than others screened with hexamethylguanidiumtetrafluoroborate having the highest distribution coefficient. Their distribution coefficients were higher than that of the convention n-dodecane used for separation of uranium and plutonium from spent nuclear fuel but having more hydrophilicity than n-dodecane. This shows that ionic liquids can be used as alternate solvents in PUREX. Key words: Ionic liquids, spent nuclear fuel (SNF), conductor-like screening model (COSMO-RS), Plutonium uranium extraction (PUREX), COSMOtherm, n-dodecane, n-tributylphosphate (TBP).

Novel Technique for Purification of Fertilizer Phosphoric Acid with Simultaneous Uranium Extraction

A process codenamed PHOSPURIN is described for the purification of Fert Phosphoric acid with simultaneous extraction of Uranium compounds from acid. This includes maintaining the acid stream at different redox potentials for the necessary extraction of all the metals & rare earths using Solvent Extraction technique. Details are also provided on the extraction behavior of various cations and rare earths from fert acid media employing redeveloped Phosphate reagent (codenamed KROPHOS-18) in kerosene system.The effects of various parameters, such as the concentration of acid, metal ion and extractant, nature of the diluents etc., on the extraction of various cations have been investigated. Based on the extraction data, most of the cations like Fe (II) & (III), Al, Mg, Ca, Mn, Na, K, heavy metals like Arsenic / Cadmium, rare earths including Uranium etc., are all being extracted with high to very high separation factors from all molar fertilizer phosphoric acids.The practical utility of the extractant & the process has been demonstrated by tests on commercial fert phosphoric acid. It has been conclusively found that KROPHOS-18 has good properties, such as high distribution coefficient, good stability, acceptable kinetics, good phase separation etc.

Extraction and determination of parabens in water samples using an aqueous two-phase system of ionic liquid and salts with beta-cyclodextrin as the modifier coupled with high performance liquid chromatography

In this study, two methods have been applied to the extraction of parabens from aqueous solution these are ionic liquid based aqueous two-phase extraction (IL-ATPS) and ionic liquid based aqueous two-phase extraction in the presence of β-cyclodextrin (β-CD) as the modifier (IL-βCD-ATPS). The IL-βCD-ATPS method consists of 1-butyl-3-methylimidazolium chloride, [C4mim][Cl] and β-CD. It is a new, green and simple extraction technique coupled with reversed-phase high performance liquid chromatography (RP-HPLC) that was applied to optimize conditions for the phase separation of parabens in water samples. The IL-βCD-ATPS method shows higher losses for water content compared to the IL-ATPS method resulting in a higher preconcentration factor and a higher distribution coefficient. A lower limit of detection of parabens in water samples was demonstrated by the IL-βCD-ATPS method. To conclude, the IL-βCD-ATPS method is superior to the IL-ATPS method for the determination of parabens in water samples. It is an economically viable approach when using β-CD because it improves the performance of the ATPS method dramatically. In addition, this chemical is cheap and non-toxic to the environment.

Cloud Point Extraction of Parabens Using Non-Ionic Surfactant with Cylodextrin Functionalized Ionic Liquid as a Modifier

A cloud point extraction (CPE) process using non-ionic surfactant (DC193C) to extract selected paraben compounds from water samples was investigated using reversed phase high performance liquid chromatography (RP-HPLC). The CPE process with the presence of β-cyclodextrin (βCD) functionalized ionic liquid as a modifier (CPE-DC193C-βCD-IL) is a new extraction technique that has been applied on the optimization of parameters, i.e., pH, βCD-IL concentration and phase volume ratio. This CPE-DC193C-βCD-IL method is facilitated at 30 °C, showing great losses of water content in the surfactant-rich phase, resulting in a high pre-concentration factor and high distribution coefficient. The developed method CPE-DC193C-βCD-IL did show enhanced properties compared to the CPE method without the modifier (CPE-DC193C). The developed method of CPE-DC193C-βCD-IL gives an excellent performance on the detection of parabens from water samples with the limit of detection falling in the range of 0.013–0.038 μg mL−1. Finally, the inclusion complex formation, hydrogen bonding, and π–π interaction between the βCD-IL, benzyl paraben (ArP), and DC 193C were proven using 1H NMR and 2D NOESY spectroscopy.

Pentacyanoferrate(II) complexes with chitosan

New organic–inorganic materials based on products of interaction between sodium aminoprusside and polymer ligand (chitosan) have been synthesized. The composition of the obtained materials was characterized using the element analysis and X‐ray diffraction; the Fourier transform infrared (FT‐IR) spectroscopy and Thermogravimetric analysis data were used to propose the structure of the formed complexes. It was established that ion and ligand exchange were the main reactions at interaction of sodium aminoprusside with water‐soluble chitosan salts. The comparative estimation of the sorption capacity with respect to cesium ions was performed for the synthesized complexes. It has been shown that the complex of chitosan with pentacyanoferrate(II) in the form of cobalt(II) salt has higher distribution coefficient with respect to Cs+ ions, as compared to cobalt aminoprusside. The maximum sorption capacity value for Cs+ was evaluated from the sorption isotherm and found to be equal to 0.3 mmol/g. POLYM. ENG. SCI., 54:2392–2397, 2014. © 2013 Society of Plastics Engineers

Adsorption Behaviors of Platinum Group Metals in Simulated High Level Liquid Waste Using Macroporous (MOTDGA-TOA)/SiO2-P Silica-based Absorbent

As fundamental research for separation of platinum group metals (PGMs) from high level liquid waste (HLLW) by macroporous silica-based adsorbent, (MOTDGA-TOA)/SiO2-P adsorbent was prepared by impregnation of N,N′-dimethyl-N,N′-di-n-octyl-thiodiglycolamide (MOTDGA) and Tri-n-octylamine (TOA) into silica/polymer composite support (SiO2-P). The adsorption behavior of Ru(III), Rh(III), and Pd(II) in simulated HLLW onto the adsorbent were investigated by the batch method to obtain their corresponding equilibrium and kinetic data. The adsorbent showed strong adsorption for Pd(II) and the adsorption reached equilibrium within 2 hr. High distribution coefficient (Kd) values for Pd(II) were obtained in 0.1–1 M HNO3 concentration. In addition, the use of both MOTDGA and TOA improved adsorption of Ru(III) and Rh(III) better than individual use of them. Especially, the Kd value for Ru(III) towards (MOTDGA-TOA)/SiO2-P adsorbent was three times larger than that in the adsorption using only with MOTDGA or TOA as extractant. The adsorptions of Ru(III), Rh(III), and Pd(II) followed the Langmuir adsorption model, and were found to be controlled by the chemisorption mechanism.

Removal of lindane from wastewater using liquid-liquid extraction process

Abstract Pesticide pollution is a serious problem being faced. Harmful levels of pesticides are found in the water which is used for daily purposes. In the event of such a scenario, this paper presents a working solution for bringing down the Pesticide levels in the water to safe levels by using the method of liquid-liquid extraction. The experimental liquid-liquid equilibrium data on pesticide-water-solvent ternary mixtures at a temperature of 288.15 K are presented here. The pesticide used here is a chlorinated hydrocarbon called lindane found in the water (underground, land), beverages and foods. The solvents used are Petro-ether-Chloroform (1:1), Ethylene di chloride and n-hexane. The equilibrium generation diagram, triangular diagram, tie lines and bimodal curves as well as the distribution coefficient have been determined and reported. The petro-ether-chloroform was found to be the right solvent for the separation of lindane from wastewater because of high selectivity (25.36) and distribution coefficient (4). The extraction process is simulated into ‘C’ language