Organic Phase In Order Research Articles

Liquid phase extraction of azo dyes by novel calixarenes bearing phthalonitrile and diiminoisoindoline groups

ABSTRACTThis paper presents a study on the removal of azo dyes [Methyl Orange (MO) and Trapaeolin 000 (TP)] from aqueous solution using new phthalonitrile and isoindoline substituted calix[n]arene derivatives into the organic phase in order to explore the potential use of these calixarenes as low-cost efficient extractants for removal of these azo dyes from wastewater. The effect of NaCl concentration, contact time, and pH on the extraction of these azo dyes was also investigated for all calixarene derivatives. The stoichiometric ratio between the calixarene derivatives (5 and 6) and selected azo dyes (MO and TP) was estimated through job’s plot.

Clean and Efficient Synthesis of Furfural From Xylose by Microwave-Assisted Biphasic System using Bio-Based Heterogeneous Acid Catalysts

As an attempt to replacing petroleum-based chemicals with bio-based ones, synthesis of furfural from biomass-derived xylose attracts much attention in recent days. Conventionally, furfural from xylose has been produced via the utilization of highly corrosive, toxic, and environmentally unfriendly mineral acids such as sulfuric acid or hydrochloric acid. In this study, microwaveassisted biphasic reaction process in the presence of novel bio-based heterogeneous acid catalysts was developed for the eco-benign and effective synthesis of furfural from xylose. The microwave was irradiated for reaction acceleration and a biphasic system consisting of H2O : MIBK (1 : 2) was designed for continuous extraction of furfural into the organic phase in order to reduce the undesired side products formed by decomposition/condensation/oligomerization in the acidic aqueous phase. Moreover, sulfonated amorphous carbonaceous materials were prepared from wood powder, the most abundant lignocellulosic biomass. The prepared catalysts were characterized by FT-IR, XPS, BET, elemental analysis and they were used as bio-based heterogeneous acid catalysts for the dehydration of xylose into furfural more effectively. For further optimization, the effect of temperature, reaction time, water/organic solvent ratio, and substrate/catalyst ratio on the xylose conversion and furfural yield were investigated and 100% conversion of xylose and 74% yield of furfural was achieved within 5 h at 180 ℃. The bio-based heterogeneous acid catalysts could be used three times without any significant loss of activity. This greener protocol provides highly selective conversion of xylose to furfural as well as facile isolation of product and bio-based heterogeneous acid catalysts can alternate the environmentally-burdened mineral acids.

Modelling of Nitric and Nitrous Acid Chemistry for Solvent Extraction Purposes

Nitric acid plays an integral role in the reprocessing of irradiated fuel. It is well known that nitric acid degrades; its often yellow hue signifies the presence of decomposition products. The decomposition of nitric acid is accelerated by temperature and radiolysis; therefore it is an important consideration in the reprocessing of nuclear fuels.Thermal and radiolytic reactions of nitric acid result in the formation of redox active nitrogen species, of which nitrous acid is of particular concern, largely due to its redox reactions with plutonium and neptunium. Such reactions are important to understand as plutonium and neptunium can exist in a number of oxidation states; the oxidation state has a direct effect on the species extractability. The effect of nitrous acid is exacerbated as it catalyzes its own production and its reactions with actinides are typically autocatalytic; thus even micromolar quantities can have a large effect. A full understanding of solvent extraction requires us to understand actinide valence states which in turn require us to understand what nitrogen species are present and their concentrations.As a first step in the overall objective of enhancing process models, the kinetic data for nitric acid decomposition reactions has been investigated in order to produce an initial dynamic model of decomposition under aqueous conditions. The identification of a set of kinetic reactions suitable for modelling has been the primary focus of this work. A model of nitric acid thermal decomposition will help develop a better understanding of nitric acid decomposition chemistry and enable better prediction of the oxidation states of species in solution. It is intended to later extend the model to include radiolytic reactions and then further to incorporate an organic phase in order to have a model which covers all decomposition routes for nitric acid within a nuclear fuel reprocessing scheme. The model will be used as a sub model for process models relating to nuclear fuel reprocessing to allow the nitric acid decomposition to be included and the effect of this on operations to be predicted. This is particularly relevant for models of maloperations where different fault scenarios can be investigated and the results of these predicted, as for example unusually high acidity could increase the yields of redox active species significantly altering actinide oxidation states.

Synthesis and dispersion of colloidal silver nanoparticles on microcellular polyHIPE support

Highly open-cell polyHIPE solid foam was prepared by polymerization of continuous organic phase of a high internal phase emulsion (HIPE) containing styrene (St), acrylonitrile (AN), divinelybenzene (DVB), and Span 80 as emulsifier. The cross-linked SAN copolymer foam was reinforced by adding 1 and 3wt% organoclay, i.e. Cloisite30B (C30B), into its emulsion organic phase in order to improve the compression properties of the resulting foam. Scanning electron micrographs indicated a typical highly open-cell structure of the neat and reinforced copolymer foams. The introduction of 1wt% C30B inside the emulsion foam significantly decreased the weighted-average cell diameter from 62 to 16.1μm, and the mean intercellular pore size from 17.9 to 4.2μm. On the other hand, the above organoclay level considerably improved the crush strength of the foam by about 271%. The surface of the foams was then coated by colloidal silver nanoparticles (SNPs) previously generated by a reduction of silver ions (Ag+) using sodium borohydride (NaBH4) as the reducing agent and polyvinyl alcohol (PVA) as the stabilizing agent. The colloidal SNPs were characterized by ultraviolet–visible (UV) spectroscopy, dynamic laser light scattering, and X-ray diffraction (XRD) techniques. The effect of PVA molecular weight, reduction temperature, and foam organoclay level on the mean size and dispersion state of SNPs dispersed on polyHIPE support has been investigated. The results showed that the SNPs prepared using low-molecular PVA at higher reduction temperature dispersed well on the support surface. A more uniform SNP dispersion as singlet was observed for the copolymer foam reinforced by organoclay.

Gold deposition on Fe3O4/(co)Poly(N‐octadecyl methacrylate) hybrid particles to obtain nanocomposites With ternary intrinsic features

AbstractHere, nanocomposite particles with three domains including magnetite nanoparticles, poly(N‐octadecyl methacrylate) (PODMA) or poly(N‐octadecyl methacrylate‐co‐1‐vinylimidazole) (P(ODMA‐co‐VIMZ)), and gold nanoparticles were prepared. Fe3O4 nanoparticles with narrow particle size distribution were prepared through a synthetic route in an organic phase in order to achieve good control of the size and size distribution and prevent their aggregation during their preparation. These magnetite nanoparticles, ∼ 5 nm in size, were then encapsulated and well‐dispersed in PODMA and P(ODMA‐co‐VIMZ) matrices via a miniemulsion polymerization process to obtain the corresponding nanocomposite particles. The results revealed that Fe3O4 nanoparticles were encapsulated and did not migrate towards the monomer/water interface during polymerization. The resulting latex was used as a precursor for the adsorption of Au3+ ions on the surface of the polymeric particles and subsequent reduction to produce Fe3O4/P(ODMA‐co‐VIMZ)/Au nanocomposite particles. The morphology of the particles from each step was fully characterized by TEM and AFM, and the results of DLS analysis showed their size and size distribution. Measurement of magnetic properties illustrated the superparamagnetic characteristic of the products and it was observed that the encapsulation process and deposition of gold had no effect on the magnetic properties of the resulting particles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Kinetic and thermodynamic study of the transfer of anionic polyamidoamine dendrimers across two immiscible liquids

The kinetics and thermodynamics for the phase transfer of carboxyl-terminated polyamidoamine (PAMAM) dendrimers across the water/dichloroethane interface were analyzed by cyclic voltammetry and electrochemical impedance spectroscopy. A three phase junction was employed by inserting a cylindrical gold electrode through the liquid–liquid interface. The reversible redox species decamethylferrocene (DMFc) was used in the organic phase in order to promote dendrimer transfer. It was found that the electrochemical behaviour of DMFc at the gold/dichloroethane interface depends on the generation and concentration of the dendrimer species in the aqueous phase. In addition, it was observed that the electrochemically driven transfer of these macromolecules corresponds to a quasi-reversible process. The data obtained from thermodynamic studies indicate that dendrimers are transferred between the two phases under study by an entropy controlled process.

Gibberellic acid extraction from aqueous solutions and fermentation broths by using emulsion liquid membranes

The extraction of gibberellic acid (GA 3), a powerful vegetal growth promoter widely used in agriculture, has been studied using emulsion liquid membrane (ELM) technology. The system used in this study consisted of a water-in-oil emulsion made of KCl aqueous solution and n-heptane stabilised by the surfactant SPAN 80. Aliquat 336, a commonly used carrier, was added to organic phase in order to increase both mass transfer and selectivity. This emulsion was dispersed on either prepared aqueous solutions of GA 3 or fermentation broths. The fermentation was performed using the fungi Gibberella fujikuroi in fed-batch modality, achieving GA 3 concentrations around 0.65 g L −1. Selection experiments pointed out that the most important variables in the extraction process were surfactant concentration (SPAN 80), carrier concentration (Aliquat 336), and time extraction. An optimisation experimental protocol was carried out using prepared GA 3 solutions, achieving the maximum extraction (88%) under the following conditions: Aliquat 336 4.3% (v/v); SPAN 80 4.4% (v/v); extraction time 20 s. When the optimisation of these variables was carried out using fermentation broth the optimum conditions found were Aliquat 336 7.4% (v/v); SPAN 80 11.2% (v/v) and extraction time 62 s. Under these conditions, the extraction yield was 68% and the concentration increase was 2.2-fold. These results suggest that GA 3 extraction using ELM is perfectly possible and its application in other configurations and scales, such as pilot scale column configuration should be considered.

Evaluation of the performance of calix[8]arene derivatives as liquid phase extraction material for the removal of azo dyes

This paper presents a study on the removal of azo dyes (Reactive Black 5, Trapaeolin 000, Methyl Orange and Direct Violet 51) with calix[ n]arene derivatives from aqueous solution into the organic phase in order to explore the potential use of calixarenes as low-cost efficient extractants for wastewater dye removal. The carboxylic acid derivative of calix[8]arene shows highest affinity towards the azo dyes. The influence of NaCl (present in the solution) on extraction process was also studied. The extent of the dye removal increased with the addition of NaCl. The proposed extraction mechanism involves several kinds of interactions: electrostatic repulsion between carboxylic acid groups of calix[8]arenes and sulfonate groups of azo dyes, hydrogen bonding and formation of an inclusion complex due to three dimensional cavity type calix[ n]arene molecules through host–guest interactions.

Mechanical Characterization of Hydroxyapatite-Based, Organic-Inorganic Composites

Hydroxyapatite-based materials have been used for dental and biomedical applications. Newly developed synthesis techniques give cause to a broad field in the study of these materials and industry demands products with better properties day by day. The purpose of the present work was to evaluate the mechanical properties of hydroxyapatite-based (HAp-based), organic-inorganic composites. HAp-based, organic-inorganic composites were obtained by modified gel casting process and organic molecules in a gelatin solution. HAp samples of different sizes and shapes were obtained with controlled micro and macro porosity and then were immersed into several gelatin solutions with different concentrations. X-ray powder Diffraction (XRD), Infra Red (IR) Spectroscopy and Scanning Electron Microscopy (SEM) techniques were used to analyze samples before and after gel casting process in order to assure that chemical and physical properties remains the same after this process. IR Spectroscopy and SEM techniques were used to characterize samples after the introduction of organic phase in order to analyze the final morphology of samples. Mechanical characterization was made in compression mode to samples without and with different concentrations of organic phase in order to establish the optimum conditions in which the highest compressive strength and Young’s modulus is reached.

Synthesis and morphological characterization of PMMA/polyaniline nanofiber composites

Poly (methyl methacrylate) (PMMA)/Polyaniline nanofibers composite films were prepared by solution casting. Doped polyaniline self-assembled nanofibers (PANFs) were synthesized by interfacial polymerization performed in an aqueous HCl/dichloromethane biphasic system in the presence of ammonium peroxydisulfate as oxidant agent. Sodium dodecyl sulfate (SDS) was added to the organic phase in order to verify possible modification the morphology the nanostrucutures when compared with previous reports. Treatment in an ultrasonic bath of PANFs on butanone resulted in a green dispersion (up to 250mg/dL). Dispersed PANFs were then combined with PMMA/butanone solution. Additional sonication and posterior film cast from solution procedures resulted in slight green PMMA/PANFs 0.15–0.30% (wt/wt) composite films. Film composites were characterized by UV–Vis spectroscopy and Scanning Electron Microscopy (SEM). PANFs powder was investigated by (SEM).An investigation by viscosity method on molecular structure of neat PMMA exposed to ultrasonic irradiation up to 2h showed small change (<5%) in the viscosity-average molar mass, Mv (≈100kg/mol). It suggests that mechanical degradation by cavitation does not occur on PMMA under those conditions. Thus, ultrasonic bath treatment is a simple, accessible method for mitigating solubility problems of PANI doped with inorganic acids and improving quality of low concentration PMMA/PANI composites. Application of these composites relies on the radiolytic stabilization effects of PANI on PMMA matrix.

ジ２エチルヘキシルジチオリン酸による硫酸溶液からのインジウム（ＩＩＩ）の抽出

The extraction of Indium (III) from sulfuric acid solutions by di-2-ethylhexyl di-thiophosphoric acid (DEHDTPA, SH) diluted in kerosene was investigated under various aqueous conditions. The distribution ratio decreases monotonically with increasing aqueous acidities. In addition, the extraction with increasing of indium concentration was studied under definite sulfuric acid concentration. It was found that indium is extracted as a 1: 3=metal: reagent complex.Infrared and high resolution nuclear magnetic resonance spectra were also studied for the extracted organic phase in order to elucidate the extraction mechanism. As the results, the following equation is given for the extraction of Indium (III) by DEHDTPA In3+ (a) +3 (SH) (o) ⇔InS3 (o) +3H (a) where S is the anion (C8H17O) 2 PS2-.Furthermore, extraction of zinc (II), cadmium (II), iron (III) and gallium (III) by DEHDTPA were carried out under various sulfuric acid concentrations. The separation factors can be accurately estmated on the basis of distribution ratios. It is apparent from the separation factors that separations of indium from zinc, iron and gallium are feasible, but that from cadmium is difficult.

Some solvents and supporting electrolytes studied for electrochemical measurement at liquid/liquid interface

AbstractSolvents used as the organic phase of electrochemical measurement at liquid‐liquid interfaces, including phenyl isothiocyanate, o‐dichlorobenzene, benzyl cyanide, propiophenone, methyl cyclohexanone, cyclohexanone, and methyl amyl ketone, have been studied. Mixing solvents of different polarities in different ratios gives a number of new solvent systems that are suitable for showing a useful “potential window,” including the mixed‐solvent systems with nitrobenzene plus phenyl isothiocyanate, nitrobenzene plus o‐dichlorobenzene, nitrobenzene plus ketones, and the mixed solvent without nitrobenzene, such as phenyl isothiocyanate plus benzyl cyanide, phenyl isothiocyanate plus benzonitrile, o‐dichlobenzene plus benzyl cyanide, and chlorobenzene plus benzonitrile. Supporting electrolytes such as cetylpyridinium tetraphenylborate, ethyl violet tetraphenylborate, and triheptyl dodecylammonium tetraphenylborate are also introduced as the organic phase in order to extend the potential range in the negative direction.

Spectrophotometric determination of low levels of anionic surfactants in water by solvent extraction in a flow injection system

An approach to automation, in routine control, for the determination of anionic surfactants in river water and treatment plant water in the concentration range 0.04–3.5 µg ml–1 using a continuous solvent extraction process with flow injection analysis, is described. The method is based on an ion-pair extraction reaction with Methylene Blue in chloroform. The separation of both phases is accomplished by means of a membrane phase separator and detection is based on injection of the coloured organic phase into a chloroform stream which passes to the detector. Methanol was added to the organic phase in order to enhance the extraction process and to ensure efficient extraction of the various anionic surfactants. A number of anionic species and non-ionic surfactants have been tested as possible interferents. The results obtained for samples of river water show good agreement with those obtained with the Methylene Blue batch method.

オクチルフェニルリン酸による硫酸溶液からのガリウム (III), インジウム (III) およびアルミニウム (III) の抽出・分離

Extractions of gallium(III), indium(III) and aluminium(III) from sulfuric acid solutions by octylphenyl phosphoric acid (OPAP) diluted in benzene were investigated under various aqueous conditions. Infrared spectra and high resolution nuclear magnetic resonance spectra were also studied for extracted organic phase in order to elucidate the extraction mechanism.Extraction of these metals decrease with an increase in aqueous acid concentrations. The order of extraction efficiency by OPAP is In(III)>Ga(III)>A1(III). Separation factors for indium/gallium, indium/aluminium and gallium/aluminium systems are calculated to 6x102, 1x104 and 30 respectively at 0.1 mol dm-3 sulfuric acid concentration in case of 2.5% OPAP, It is apparent from the separation factors that the separation of indium from gallium, indium from aluminium and gallium from aluminium are feasible.From IR spectra, it is proved that the extraction mechanism by OPAP is similar to that by di-2-ethylhexyl phosphoric acid (DEHPA). It is suggested from NMR spectra that the introduction of phenyl groups is effective for extractions of gallium and indium from sulfuric acid solutions.The recovery of gallium and indium from sulfuric acid solutions by OPAP has been carried out for mixed solutions containing gallium, indium and aluminium with results of a good agreement between the expected and experimental data.

Measurement of acidity constants of benzothiadiazines by solvent extraction with use of a membrane phase-separator

For extraction studies a “filter-probe” porous Teflon membrane phase-separator is used in conjunction with a spectrophotometer fitted with a small-volume flow-cell and a peristaltic pump to measure absorbance of the organic phase as a function of aqueous phase pH. Acidity constants of monoprotic (HA) and diprotic (H 2A) acid benzothiadiazines have been measured with the apparatus. Accurate p K a, values for these compounds are difficult to measure by other techniques. Mixtures of n-octanol and chloroform in various proportions can be used as the organic phase in order to adjust the distribution coefficient of the neutral species to give optimum precision and accuracy in measurement of the p K a values.