Solvent extraction studies of Sm(III) from nitrate medium and separation factors of rare earth elements with mixtures of sec‐octylphenoxyacetic acid and 1,10‐phenthroline

BACKGROUND: Liquid–liquid extraction is widely used for the separation of rare earths, among which synergistic extraction has attracted more and more attention. Numerous types of synergistic extraction systems have been applied to rare earths with high extraction efficiency and selectivities. In the present study, mixtures of sec‐octylphenoxyacetic acid (CA12, H₂A₂) and 1,10‐phenanthroline (phen, B) have been used for the extraction of rare earths from nitrate medium. The stoichiometry of samarium(III) extraction has been studied using the methods of slope analysis and constant molar ratio. The possibility of using synergistic extraction effects to separate rare earths has also been studied. RESULTS: Mixtures of CA12 and phen display synergistic effects in the extraction of rare earth elements giving maximum enhancement coefficients of 5.5 (La); 13.7 (Nd); 15.9 (Sm); 24.5 (Tb); 45.4 (Yb) and 12.3 (Y). Samarium(III) is extracted as SmHA₄B₃ with mixtures of CA12 and phen instead of SmHA₄ when extracted with CA12 alone. The calculated logarithm of the equilibrium constant is 6.0 and the thermodynamic functions, ΔH, ΔG, and ΔS, have been calculated as 4.3 kJ mol^?1, ? 33.7 kJ mol^?1 and 129.7 J mol^?1 K^?1, respectively. CONCLUSION: Mixtures of CA12 and phen exhibit synergistic effects on rare earth elements. Graphical and numerical methods have been successfully used to determine their stoichiometries. The different synergistic effects may provide the possibility of separating yttrium from heavy lanthanoids at an appropriate ratio of CA12 and phen. Copyright © 2010 Society of Chemical Industry     

Simultaneous extraction and purification of myricetin from Chamaecyparis obtusa by multi‐phase extraction with ionic liquid‐modified mesoporous MCM‐41

BACKGROUND: Multi‐phase extraction is a novel method for the simultaneous extraction and separation of myricetin from Chamaecyparis obtusa . In this research, an amino ionic liquid‐modified MCM‐41 was used as the sorbent and the sample was packed with it into a cartridge. A fixed volume of solvent was then use to extract the target compound with several repetitions and to remove the myricetin to the sorbent. The washing and elution of solvent were investigated. RESULTS: FT‐IR and element contents tests confirmed that the ionic liquid groups were successfully immobilized on MCM‐41. 0.184 mg myricetin was extracted with five repetitions of 1.0 mL methanol. Then 2.0 mL n‐hexane and water were removed all the interference and 1.0 mL methanol was purified 0.1 mg myricetin from 0.2 g ionic liquid‐modified MCM‐41. CONCLUSION: Base on a comparison with traditional extraction methods, the low deviation error (3.16%), small amount of solvent required, highly selective separation and stability of the proposed method justify continuing its development. Copyright © 2011 Society of Chemical Industry     

Measurements of horizontal three‐phase solid‐liquid‐gas slug flow: Influence of hydrate‐like particles on hydrodynamics

Gas hydrate formation is a main flow assurance concern in oil and gas production. Understanding the effects of the introduction of solid particles in the slug flow is essential to improve the efficiency and safety of multiphase production. The purpose of the present work is the experimental characterization of solid‐liquid‐gas slug flow with the presence of dispersed hydrate‐like particles. Experimental tests were carried out with inert polyethylene particles of 0.5‐mm diameter with density similar to gas hydrates (938 kg/m³). The test section comprised a 26‐mm ID, 9‐m length horizontal duct of transparent Plexiglas. High Speed Imaging and resistivity sensors was used to analyze the slug flow unit cell behavior due to the introduction of the solid particles and to measure the unit cell translational velocity, the slug flow frequency, the bubble and slug lengths, and the phase fractions. Two distinct concentrations of solid particles were tested (6 and 8 g/dm³). © 2018 American Institute of Chemical Engineers AIChE J, 64: 2864–2880, 2018     

Cloud point and solvent extraction study of uranium(VI) by 8‐hydroxyquinoline

BACKGROUND: Cloud point extraction (CPE) is an attractive alternative to solvent extraction. However, comparisons between both techniques are lacking. In this paper, the extraction of uranium(VI) using 8‐hydroxyquinoline (HQ) as chelating agent was studied by CPE using Triton X‐114 as non‐ionic surfactant and by solvent extraction using CHCl₃ as diluent. RESULTS: Using CPE, a quantitative extraction was observed for pH higher than 4.5 with a HQ/U ratio of 10. Using solvent extraction an increase in the HQ/U ratio up to 50 is necessary to obtain a near quantitative extraction. Both extraction systems were then compared with respect to the nature of extracted species, and the extraction constants determined using log‐log analysis of the extraction data. In the solvent extraction system, the extracted species were identified as UO₂Q₂ and the corresponding extraction constant was found to be log k_ex = ? 3.6 ± 0.2 on the molar scale. Considering that UO₂Q₂ is also the extracted species in CPE, a slightly higher extraction constant, i.e. log k_ex = ? 2.5 ± 0.3, was found. CONCLUSION: Such a small difference in favour of the CPE system may arise from the combination of various phenomena, including effects of temperature and effects of ‘extractant environment’. However, a change in the nature of the extracted species, namely from UO₂Q₂ in the solvent extraction system to the formation of adducts, i.e. UO₂Q₂(HQ) and UO₂Q₂(HQ)₂ in the CPE system, due to higher HQ concentration in the surfactant‐rich phase compared with chloroform, cannot be precluded, but requires confirmation. Copyright © 2012 Society of Chemical Industry     

Chemical conversion and liquid–liquid extraction of 5‐hydroxymethylfurfural from fructose by slug flow microreactor

A dehydration of fructose in the water/methyl isobuthyl ketone (MIBK) biphasic system can yield 5‐hydroxymethylfurfural (HMF) to be successfully extracted into the organic MIBK phase. The HMF production and yield in MIBK phase was discussed by using a simplified model taking into consideration of the slug flow. The extraction resistance of HMF across the interface between water and MIBK depended on the line velocity and the flow rate ratio. It was likely that the velocity field generated in the slug flow contributed to an increase in the mass transfer of HMF. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2135–2143, 2016     

Synthesis of n‐butyl phenyl ether by tri‐liquid‐phase catalysis using poly(ethylene glycol)‐600 as a catalyst – analysis of factors affecting the reaction in a batch reactor

As the second part of a series of studies on the synthesis of n‐butyl phenyl ether (ROPh) by tri‐liquid‐phase catalysis, this work examines the factors affecting the reaction between n‐butyl bromide (RBr, organic substrate) and sodium phenolate (NaOPh, aqueous nucleophile) with poly(ethylene glycol)‐600 (PEG‐600) as a phase‐transfer catalyst. The reaction is performed in a batch reactor at 45–85 °C for 2 h while the agitation speed is fixed at 1000 rpm. Experimental results indicate that the individual mole fractions of NaOPh and PEG‐600 slightly affect the reaction, while the total amount of these components exerts significant influence. When the mole fraction of PEG‐600 is 0.5, the reaction rate and the conversion of RBr are the highest. No byproducts are formed in the course of the reaction. The system using a non‐polar organic solvent might obtain a higher conversion compared with a weakly polar one owing to a higher concentration of PEG‐600 in the third liquid phase. Furthermore, adding NaOH facilitates the reaction to obtain a higher reaction rate than adding other kinds of salt because the addition of a base results in the formation of a third liquid phase. The catalytic ability of PEG with average molecular weight of 600 gmol^?1 is far higher than that with average molecular weight of 200, 400 and 1000 because PEG‐600 possesses an appropriate chain length which can tightly associate with Na⁺ to form the complex of PEG‐600‐Na⁺OPh^? for reacting with RBr. In addition, this nucleophilic substitution reaction is found to be pseudo‐first‐order with respect to RBr. © 2001 Society of Chemical Industry     

Impact of polyethylene glycol as additive on the formation and extraction behavior of ionic‐liquid based aqueous two‐phase system

Developing a novel Ionic‐liquid (IL) based aqueous two‐phase system (ATPS) with polyethylene glycol (PEG) as adjuvant for the separation of biomolecules is studied. This original work involves addition of various concentration of PEG (2000, 4000, and 6000 gr/mol) to 1‐butyl‐3‐methylimidazolium acetate+ potassium hydrogen phosphate ATPS to investigate their subsequent effect on phase diagrams and partitioning coefficient of α‐amylase. In another innovative aspect of this work, response surface methodology (RSM) based on three‐variable central composite design was employed to understand the effect of phase forming components on extraction studies of α‐amylase. The addition of small amount of PEG improved the partitioning coefficient of biomolecule. The effective excluded volume theory was applied to correlate the salting‐out ability. As a result, it can be stated that the proposed system can effectively be used in separation and purification studies instead of task specific ILs. © 2015 American Institute of Chemical Engineers AIChE J, 62: 264–274, 2016     

Homogeneous liquid–liquid extraction using perfluorooctanesulfonic acid and calcium and its application to the separation and recovery of vitamin B12

A new phase separation phenomenon was observed in which the perfluorooctanesulfonate ion (PFOS⁻) and calcium ion form an ion‐pair associator and the sedimented liquid phase occurs from the homogeneous aqueous solution. This phenomenon was observed in the neutral pH region at room temperature (25 °C). The optimum concentration conditions for the reagents were [PFOS⁻]_T = 7 × 10⁻³ mol dm^‐3 and [Ca²⁺]_T = 1.1 mol dm^‐3. When these findings were applied to the homogeneous liquid–liquid extraction of vitamin B₁₂, the extraction percentage (E) was 83% and the concentration ratio (ie V_a/V_s, where V_a is the volume of the aqueous phase and V_s is the volume of the sedimented liquid phase) was a maximum of 149. The recovery of vitamin B₁₂ was achieved by adding the propanol–acetone (20 : 80 v/v%) mixed solvent to the sedimented liquid phase; the vitamin B₁₂ precipitated and was filtered. Both the PFOS⁻ and Ca²⁺ were removed by dissolution in the mixed solvent. The recovery percentage of vitamin B₁₂ was 78%. © 1999 Society of Chemical Industry     

Solvent extraction separation of titanium(IV), vanadium(V) and iron(III) from simulated waste chloride liquors of titanium minerals processing industry by the trialkylphosphine oxide Cyanex 923

The solvent extraction of magnesium(II), aluminium(III), titanium(IV), vanadium(V), chromium(III), manganese(II) and iron(III) from hydrochloric acid solutions has been investigated using the trialkylphosphine oxide Cyanex 923 (TRPO) in kerosene as extractant. The results demonstrate that titanium(IV), vanadium(V) and iron(III) are extracted into kerosene as TiOCl₂·2TRPO, VO₂Cl·TRPO and HFeCl₄·2TRPO, respectively. On the other hand magnesium(II), aluminium(III), chromium(III) and manganese(II) are not extracted with TRPO from hydrochloric acid solutions (1.0–4.0 mol dm^?3) under the experimental conditions. IR spectral studies of the extracted complexes were further used to clarify the nature of the extracted complexes. The effect of the diluent on the extraction of titanium(IV), vanadium(V) and iron(III) has been studied and correlated with the dielectric constant. The loading capacity of the TRPO system has been evaluated and the potential for the separation and recovery of titanium(IV), vanadium(V) and iron(III) from simulated waste chloride liquors of the titanium minerals processing industry has been assessed. Copyright © 2004 Society of Chemical Industry     

Hydrodynamic considerations on optimal design of a three‐phase airlift bioreactor with high solids loading

The hydrodynamic study of a three‐phase airlift (TPAL) bioreactor with an enlarged gas–liquid dual separator was carried out. Different lengths and diameters of the draft tube were tested to show how the design of the separator zone affects the hydrodynamic performance of the TPAL reactor. Ca‐alginate beads with entrapped yeast biomass at different loadings (0, 7, 14 and 21% v/v) were used in order to mimic the solid phase of conventional high cell density systems, such as those with cells immobilized on carriers or flocculating cells. Important information on multiphase flow and distribution of gas and solid phases in the internal‐loop airlift reactor (ALR) with high solids loading was obtained, which can be used for suggesting optimal hydrodynamic conditions in a TPAL bioreactor with high solids loading. It is finally suggested that the ALR with a dual separator and a downcomer to riser cross‐sectional area ratio (A_D/A_R) ranging from 1.2 to 2.0 can be successfully applied to batch/continuous high cell density systems, where the uniform distribution of solid phase, its efficient separation of particles from the liquid phase, and an improved residence time of air bubbles inside the reactor are desirable. Copyright © 2003 Society of Chemical Industry     

Insoluble porous conjugated polymer films via phase separation and photo‐crosslinking for the trace detection of 2,4‐dinitrotoluene

A novel conjugated polymer film with microscale/submicroscale porous morphology fabricated from crosslinked poly(fluorene‐co‐carbazole) (PFC1) was developed for the detection of 2,4‐dinitrotoluene (DNT). The fluorescent conjugated polymer PFC1 with pendant photo‐crosslinkable coumarin groups was synthesized by Suzuki coupling polymerization. Taking advantage of the phase separation of PFC1/polystyrene (PS) blends in the film and the solvent‐resistant network, porous structured films were prepared by removal of PS. Films with porous morphologies exhibited marked responsive sensitivity to trace DNT vapor due to the unique porous structure favoring the diffusion of and association with DNT molecules. The formation of a crosslinked network by dimerization of the coumarin moieties may be beneficial for isolating the polymeric backbones, thus to some extent preventing chain aggregation. This facile fabrication method enabled the crosslinked porous films to be efficient fluorescence chemosensors towards the detection of trace amounts of DNT vapor.© 2012 Society of Chemical Industry     

Effect of diluents on the crystallization behavior of poly(4‐methyl‐1‐pentene) and membrane morphology via thermally induced phase separation

The effect of diluents on polymer crystallization and membrane morphology via thermally induced phase separation(TIPS) were studied by changing the composition of the mixed‐diluents systematically, in the system of poly(4‐methyl‐1‐pentene) (TPX)/dibutyl‐phthalate (DBP)/di‐n‐octyl‐phthalate (D‐n‐OP) with TPX concentration of 30 wt %. The TPX crystallization was observed with differential scanning calorimetry (DSC) and wide angle X‐ray diffraction (WAXD). The membranes were characterized with scanning electron microscopy (SEM), porosity, and pore size measurement. As the content of D‐n‐OP increased in mixed‐diluents, the solubility with TPX increased, inducing the phase separation changing from liquid–liquid phase separation into solid–liquid phase separation, which changed the membrane morphology and structure. When the ratios of DBP to D‐n‐OP were 10 : 0, 7 : 3; 5 : 5, and 3 : 7, membranes were formed with cellular structure and well connected pores, while the ratio was 0 : 10, discernable spherulities were found with not well‐formed pore structure. The effect of composition of the mixed‐diluents on membrane morphology was more remarkable in TPX/dioctyl‐sebacate (DOS)/dimethyl‐phthalate (DMP) system, since good cellular structure was formed when the ratios of DOS to DMP were 10 : 0, 7 : 3, while spherulites were observed when 5 : 5. Dual endotherm peaks behavior on DSC melting curves emerged for all the samples in this study, which was attributed to the special polymer crystallization behavior, primary crystallization, and secondary crystallization occurred when quenching the samples. As the content of D‐n‐OP increased, the secondary crystallization enhanced which induced the first endotherm peak on DSC melting curves moving to a lower temperature and the broadening of the overall melting peak, as well as the increasing of the overall crystallinity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Structure control of asymmetric poly(vinyl butyral)‐TiO2 composite membrane prepared by nonsolvent induced phase separation

Poly(vinyl butyral) (PVB)‐TiO₂ composite hollow fiber membranes were prepared via nonsolvent induced phase separation (NIPS). The membrane had a skin layer on both the outer and inner surface at the initial stage after membrane preparation. However, the outer surface became porous with the passage of time, as the polymer in the membrane's outer surface was decomposed by the photocatalysis of TiO₂. The initial water permeability increased with the increase of TiO₂ content. Furthermore, for all the membranes, as time elapsed the water permeabilities increased and became constant after about 15 days, which was in accordance with the alteration on the membrane's outer surface. Despite decomposition of the polymer on the outer surface, particle rejection hardly changed because the inner surface kept the original structure. Thus, addition of TiO₂ to the membrane is a useful way to improve water permeability while maintaining particle rejection. The clear asymmetric structure with both porous structure at the outer surface and skin layer at the inner surface was achieved by the addition of TiO₂. Therefore, the addition of TiO₂ is a new method for achieving the high porosity at the outer surface of the hollow fiber membrane. In addition, tensile strength and elasticity kept constant over time and were higher than those of original PVB membranes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Selective solid‐phase extraction of naphazoline using imprinted polymers as matrix prepared by precipitation polymerization

The molecularly imprinted polymers (MIP) for drug naphazoline (NAZ) have been synthesized by precipitation polymerization. The effect of the dispersive solvents dichloromethane (DCM), acetonitrile (ACN), and Methanol (MeOH) on particle size and morphology of MIP (P1, P2, and P3) was investigated by scanning electron microscopy (SEM). The selectivity of P1, compared with nonimprinted polymer (NIP), C₈ and C₁₈ were evaluated via static adsorption using UV spectrophotometer. The result showed that the bond amount of P1 for NAZ was significantly higher than other sorbents. The P1 were applied as a solid‐phase extraction (SPE) stationary phase to extract the NAZ from nasal drops and recoveries of more than 89% (relative standard deviations, RSD <5%) were obtained by high performance liquid chromatograph (HPLC) analyses. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Dehydrogenation of 11α‐hydroxy‐16α, 17‐epoxyprogesterone by encapsulated Arthrobacter simplex cells in an aqueous/organic solvent two‐liquid‐phase system

BACKGROUND: Arthrobacter simplex cells immobilised in sodium cellulose sulfate/poly‐dimethyl‐diallyl‐ammonium chloride microcapsules were used for the microbial dehydrogenation of 11α‐hydroxy‐16α,17‐epoxyprogesterone to 11α‐hydroxy‐16α,17α‐epoxypregn‐1,4‐diene‐3,20‐dione in an aqueous/organic solvent two‐liquid‐phase system, which is a key reaction in the production of glucocorticoid pharmaceuticals. The aim of the study was to establish a suitable aqueous/organic solvent two‐liquid‐phase system for performing semi‐continuous production in an airlift loop reactor by encapsulated A. simplex cells with the addition of suitable surfactants to achieve a higher yield of the product. RESULTS: n‐Hexane was selected as the most suitable organic solvent. In optimised Tween‐80 emulsion feed mode the conversion in the airlift loop reactor was as high as 97.54% when the time of reaction was 2 h, and the reaction time was greatly shortened. In semi‐continuous production the cultivation with immobilised cells was carried out for five batches in total. The conversion in each batch was above 95% and the enzymatic activity still remained quite high after five batches of biotransformation. CONCLUSION: The results showed that performing the conversion by this method shortened the reaction time and increased the productivity, thus demonstrating the great potential of the method for the dehydrogenation of 11α‐hydroxy‐16α,17‐epoxyprogesterone. Copyright © 2008 Society of Chemical Industry     

Formation of bulk titanium boride (TiB) nano‐ceramic with Fe–Mo addition by electric‐field‐activated‐sintering

The present work is focused on optimization of Fe–Mo content, which is essential for transient liquid phase formation and densification, during in‐situ reaction sintering of nanostructured titanium boride (TiB) in the bulk form. The principle objective is to develop a systematic understanding of how the Fe–Mo additions affect the densification, microstructure, and hardness of the TiB nano‐ceramic. Various TiB ceramic compositions, with varying Fe–Mo content and retaining a high‐volume fraction of TiB in the final microstructure, were made by the electric‐field‐activated‐sintering (EFAS) technique. An increase in Fe–Mo content is found to decrease the beginning point of densification temperature/time during the consolidation process through transient liquid phase formation. It is shown that at the optimum level of Fe–Mo, which is around 1.5 wt%, the density and hardness reach maximum levels with a least amount of spatial segregation of Fe within the ceramic. Interestingly, it has been found that Mo is uniformly incorporated within the orthorhombic lattice of the boride, while Fe is largely segregated to β‐Ti phase. At the optimal Fe–Mo content (1.5 wt%), a relative density of 99.7% and a Vickers hardness of 2050 ± 40 kg/mm² were achieved. From microstructural and X‐ray diffraction analyses, it is found that a high proportion of TiB (>99 vol%), with a least amount of metallic ductile phase, is formed in this composition.     

Shape memory property and underlying mechanism by the phase separation control of poly(ϵ‐caprolactone)/poly(ether‐b‐amide)

In this work, a poly(?‐caprolactone)/poly(ether‐b‐amide) blend with weight ratio 35/65 was prepared by solution mixing and compression molding. A simple and sensible method to control the phase separation structure was introduced by adjusting the temperature and time for the process of phase separation. Samples with obviously different morphology were obtained and the microstructure was studied by phase contrast optical microscopy, SEM and DSC. The shape memory properties were measured using dynamic mechanical analysis. The results show that the shape memory performance of the blend is closely related to the phase morphology, and the blend with co‐continuous structure has a better shape memory property. A model is put forward to illustrate schematically the microstructural evolution during the shape memory process. © 2018 Society of Chemical Industry     

Structure and drug release of superabsorbent sponge prepared by polyelectrolyte complexation and freezing‐induced phase separation

Superabsorbent sponge with uniform porous structure was prepared by polyelectrolyte complex (PEC) of polyacrylic acid (PAA) with inorganic polymers, high polymer state polyaluminum chloride (HPSPAC), in combination with freezing‐induced phase separation (FIPS). The above superabsorbent sponge was prepared under mild conditions, without strong heat, oxidation, or corrosion, which is an ideal superabsorbent material for drug embedding. Structure analysis and swelling kinetics of the superabsorbent sponge as well as kinetics of the release of the model drug, 4‐acetaminophen (AMP), from the sponge were investigated. In addition, effects of the crosslinker HPSPAC, the pH of the solution, and the concentration of NaCl solution on the structure and the swelling property of the sponge and sustained‐release kinetics were explored. Further, the relationship between the structure of the superabsorbent sponge and its swelling property as well as sustained drug‐release characteristics was investigated. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012