Cyanex 471X Research Articles

Investigation of the iridium adsorption process with functionalized magnetic nanoparticles using triisobutylphosphine sulfide extractors

In this research work, the adsorption process of iridium using magnetic nanoparticles functionalized with Cyanex 471X has been investigated. In this regard, parameters affecting the adsorption process such as pH, initial concentration of iridium ions, contact time and adsorbent dosage were assessed. According to the results, pH 6, adsorbent dosage 1.2 g/L, initial concentration of iridium of 10 mg/L, and contact time of 10 min were selected as optimal conditions for iridium adsorption by this synthesized magnetic nanosorbent. The kinetics of the adsorption process was studied, and it was found that the adsorption reaction follows the pseudo-second-order kinetic model with the correlation coefficient of 0.9960. Also, experimental studies indicated that the Langmuir adsorption isotherm model best matches the experimental data (R2 = 0.9961). The maximum adsorption capacity of the nanosorbent for iridium adsorption was estimated to be 35.34 mg/g by the Langmuir isotherm. With the thermodynamic analysis of the adsorption process, it was found that this process is endothermic and spontaneous. In addition, in the investigation of iridium adsorption and desorption, HCl/HNO3 solution with a concentration of 1.5 M was selected as suitable eluent.

Styrene divinyl benzene beads (SM-2) functionalized with triisobutylphosphine sulfide for selective uptake of palladium(II) from nitric acid medium

Resins impregnated with organic extractants regarded as effective adsorbent materials due to their ability for selective sorption. These resins consist of a polymeric material that is infused with accessible organic extractants. Furthermore, these resins merge the unique properties and the distinctive characteristics of both liquid-liquid extraction and solid-liquid sorption processes. In this work, the impregnation of Styrene divinyl benzene beads (SM-2 beads) with triisobutylphosphine sulfide (TIBPS = CYANEX 471X) was prepared. A SM-2 bead functionalized with CYANEX 471X (SM-2-TIBPS beads) was characterized using scanning electron microscope (SEM) and Fourier-transform infrared spectroscopy (FT-IR) techniques and investigated for recovery and separation of palladium ions from a 3 M nitric acid solution. Various parameters were studied, as shaking time effect, nitric acid concentration, SM-2-TIBPS beads weight, Pd(II) concentration and temperature. The Pd(II)/SM-2-TIBPS sorption system has an endothermic nature and was fitted with a Langmuir isotherm model with a 0.9860 regression factor. The kinetics modeling was fitted with PSO and IPD models with regression factors of 0.9889 and 0.9959, respectively. The maximum monolayer sorption capacity of SM-2-TIBPS was found to be 17.47 ± 0.9 mg/g. The sorption of Pd(II) from different media at 3 M takes the following sequence: HNO3 > HCl > H2SO4. Desorption of about 76.38 ± 2.4% was achieved with (1 M + 1 M) of thiourea + HCl after one desorption stage. Effect of other interfering ions, as Pt(II), Pb(II), Eu(III), Cu(II), Mo(VI), Co(III), Zr(IV), Fe(III), Cd(II), and Ce(III), indicates high separation factors between Pd(II) and other investigated metal ions, which ranged from 9.4 to 35.

Gamma radiation synthesis of hydroxyethyl cellulose/acrylic acid/CYANEX 471X hydrogel for silver ions capture from acidic nitrate medium

The current novelty in this study is to recover silver ion with selective extractant such as cyanex 471X (triisobutylphosphine sulfide) through a clean and green method with high efficiency. Herein, a sustainable hydrogel (HEC/AAc/CX3) was fabricated from triisobutylphosphine sulfide, hydroxyethyl cellulose (HEC), and acrylic acid (AAc) using gamma irradiation polymerization and implanted for the sorption of silver Ag (I) ions from a nitrate acidic medium. Different techniques were employed for characterization of HEC/AAc/CX3 hydrogel such as FT-IR, SEM, XRD, and EDX, before and after the sorption process of Ag(I) ions. Gel content and swelling kinetics ratio of hydrogels at different irradiation doses (10, 20, 30, 40, and 50 kGy) were studied. The Fickian diffusion model results indicate that HEC/AAc/CX3 hydrogel is non-Fickian diffusion, which confirmed that the diffusion and relaxation rates are compatible and were selected for further sorption of Ag(I). The irradiated HEC/AAc/CX3 hydrogels, which contain 0.1 g of cyanex 471X, were employed for batch sorption of 100 mg/L Ag(I) from an acidic solution, and the suggested conditions were pH = 1, time = 60, and v/m = 0.05 L/g, which gives a sorption percentage of 75%. The values of thermodynamic parameters ΔH, ΔG, and ΔS were evaluated as—62.80 kJ/mol, 5 kJ/mol, and -227 J/mol, which indicate that the sorption system was exothermic and nonspontaneous in nature. The maximum adsorption capacity of irradiated HEC/AAc/CX3 for Ag(I) was found to be 12 mg. g−1 at 298 K. Furthermore, the maximum desorption percent of Ag ions from HEC/AAc/CX3 was found to be 70% and achieved with 0.5 M NH4SCN after one desorption cycle. The prepared hydrogel proved its selectivity towards silver ions with facile desorption steps and reusability cycles.Graphical

Analytical Performance of Electromembranes as a Tool for Nanoconcentrations of Silver in Waters.

Electromembranes increase the efficiency of metal transport in liquid-phase microextraction systems by applying an electric potential, which accelerates the transport. Nevertheless, to get high extraction percentages in short extraction times it is necessary to take into account a great variety of factors, and multivariate optimization techniques are the best alternative to determine the most influential variables and to optimize the extraction process. In this work, a fractional factorial design was applied to determine the most influential variables in the extraction of silver by electromembranes. Thus, the effect of tri-isobutylphosphine sulphide (Cyanex 471x) concentration in the organic solution, sodium thiosulphate concentration in the acceptor solution, nitrate concentration in the sample solution, extraction time, stirring rate and electric potential on the enrichment factor were studied. Once the most important variables were selected, a small composite design (Draper-Lin) was used to obtain their optimal values to maximize the enrichment factor. Under these conditions, an experimental enrichment factor of 49.91 ± 3.95 was achieved after 22 min. Finally, the effect of saline matrix on the enrichment factor was tested and the optimized system was successfully applied to analyse silver concentrations at ultratrace levels, within the range of 7-29 ng·L-1 in different real seawater samples.

Extraction of Palladium from Nitrate Medium by Emulsion Liquid Membrane Containing CYANEX 471X as Carrier

ABSTRACTExtraction of Pd(II) from nitric acid solution with CYANEX 471X in chloroform was carried out using liquid–liquid extraction and emulsion liquid membrane (ELM) techniques. Extraction equilibrium was postulated using the slope analysis method. KSCN solution efficiently stripped Pd(II). In the ELM investigations, the effects of the different parameters affecting the membrane stability were studied. The prepared membrane was found to be selective for Pd(II) extraction in the presence of some interfering ions and its permeation reached 98%. The kinetics of Pd(II) permeation through the prepared membrane indicated that the rate of permeation depends on the carrier, Pd(II), and nitric acid concentration.

HIGHLY EFFICIENT FACILITATED MEMBRANE TRANSPORT OF PALLADIUM(II) IONS FROM HYDROCHLORIC ACID SOLUTIONS THROUGH PLASTICIZER MEMBRANES WITH CYANEX 471X

In this work the efficient recovery of palladium(II) ions from hydrochloric acid solutions by transport through polymer inclusion membranes (PIMs) was studied. The membrane consisted of cellulose triacetate (CTA) as the polymeric support, o-nitrophenyl octyl ether (ONPOE) as the plasticizer and Cyanex 471X (triisobutylphosphine sulphide) as the ion carrier. The effect of various parameters on the transport kinetics and the recovery factor of palladium(II) was studied, including concentration of Cyanex 471X in the membrane, hydrochloric acid concentration in the source phase and potassium thiocyanate (KSCN) concentration in the receiving phase.

Extraction and separation studies on Pt(IV), Ir(III) and Rh(III) using sulphur containing extractant

The present work reports distribution of platinum(IV), iridium(III) and rhodium(III) from HCl, H2SO4 and HNO3 (0.1–6molL−1) media using Cyanex 471X diluted with toluene. Detailed studies have been conducted to evaluate the effect of different variables influencing the extraction such as equilibration time, temperature, diluent and concentration of extractant. An assessment of the loading capacity, regeneration power and stability of extractant has been made. The extraction behaviour of associated metals namely gold, silver, iron, nickel, cobalt, chromium and copper has been investigated and the conditions for their binary separations involving platinum metals have been optimised. The stoichiometric composition of the extracting platinum and iridium species have been identified. Based on the extraction data separation schemes have been designed to recover platinum, iridium and rhodium from synthetic mixture and real sample.

Separation of Silver(I) and Copper(II) from Aqueous Solutions by Transport through Polymer Inclusion Membranes with Cyanex 471X

In this work the selective transport of silver(I) and copper(II) ions from aqueous nitrate(V) solutions by transport through polymer inclusion membrane (PIM) has been studied. The membrane consisted of cellulose triacatate (CTA) as the polymeric support, o-nitrophenyl pentyl ether (ONPPE) as the plasticizer and Cyanex 471X (triisobutylphosphine sulphide) as the ion carrier. Ag(I) ions were effectively removed from the source phase by transport through PIM into 0.01 M Na2S2O3 as the receiving phase. The influence of membrane composition on the transport of silver(I) ions has been evaluated.

A new contamination-free method for the determination of traces of anthropogenic silver in freshwaters

The use of different products containing silver in anthropic activities has caused the increase of silver concentrations in many water courses. To establish their toxic effects, both precise and accurate analytical methods are needed to quantify silver at very low concentrations. Although different methods may be found in the literature, in practice, most chemists or other environmentalists use solvent extraction methodology in a Clean Lab, which is tedious and with high risk of sample contamination during manipulation. In this work, the applicability of a liquid membrane-based method was studied as an alternative for the analysis of silver in freshwaters using triisobutylphosphine sulphide, TIBPS (Cyanex 471X©), as a carrier. Transport conditions were studied and optimised; including pH and co-ion (nitrate) concentration in sample, the influence of anionic species present in freshwaters, and concentrations of carrier and stripping reagent. Under optimum conditions an extraction efficiency of 59.5% was achieved after a 4-hours operation time. Since both extraction and back-extraction processes are carried out simultaneously and without sample manipulation, this system offers a clean alternative (avoiding contamination) for determination of traces and ultra-traces of silver in freshwaters. The system was successfully applied to the preconcentration of silver, in tap and freshwater samples, before their quantification by flame atomic absorption spectroscopy (FAAS) at a ppb-level or by inductively coupled plasma-mass spectrometry (ICP-MS) at the ppt-level.

Mercury determination in sediments by CVAAS after on line preconcentration by solid phase extraction with a sol-gel sorbent containing CYANEX 471X®

The development of a preconcentration method for the measurement of trace levels of mercury in digested sediments is described. Solid phase extraction (SPE) was used for the preconcentration of mercury coupled on-line by means of a flow injection (FI) system followed by cold vapour atomic absorption spectrometry (CVAAS) detection. The SPE was carried out through a column packed with a sorbent material containing triisobutylphosphine sulfide (CYANEX 471X®) as mercury extractant and prepared by the sol-gel process. The effects of FI variables (argon, eluent, and reductant flow rates, loading and elution times) as well as the eluent concentration on the analytical performance of the method were evaluated. The proposed method was validated under the optimum conditions. The calibration graph was linear from 0.05 µg L−1 to 3.0 µg L−1 of Hg. The detection limit (DL), based on three times the standard deviation of the blank measurement criterion, was 24 ng L−1. The repeatability was 1.5% and 1.8% RSD (n = 10) at concentrations of 0.5 and 1 µg L−1 of Hg, respectively. Method enrichment factors of 16 with a productivity of 30 samples h−1 or 32 with a productivity of 17 samples h−1 were achieved under selected conditions. Certified reference materials, inductively coupled plasma mass spectroscopy (ICP-MS) and cold vapour atomic fluorescence spectrometry (CVAFS), were used to evaluate the accuracy of the proposed method.

Extraction of palladium from nitrate solution by CYANEX 471X

In this work, the extraction of Pd(II) with triisobutylphosphine sulfide (CYANEX 471X) in kerosene from nitric acid medium has been studied. The effects of different parameters affecting the extraction of the investigated metal ion such as nitric acid, extractant, metal ion concentration and temperature were separately investigated. The stoichiometry of the extracted metal species was found to be Pd(NO 3) 2.CYANEX 471X. The stripping of the extracted metal species was carried out using stabilized thiosulfate solution. The results indicate the possibility of separation of palladium from some interfering ions namely; Co(II), Fe(III), Cu(II), Cd(II) and Zn(II). Extraction of Pd(II) from hydrochloric and sulfuric acid media was also carried out. Thereafter, the method developed was applied for the recovery and separation of Pd and other metal ions from a synthetic solution similar in composition to that expected from the leaching of spent automotive catalyst in hydrochloric acid.

Analytical approaches for Hg determination in wastewater samples by means of total reflection X-ray fluorescence spectrometry

At present, there is a considerable interest in Hg monitoring in wastewater samples due to its widespread occurrence and the high toxicity of most of its compounds. Hg determination in water samples by means of total reflection X-ray fluorescence spectrometry (TXRF) entails some difficulties due to the high vapor pressure and low boiling point of this element that produce evaporation and loss of Hg from the surface of the reflector during the drying process, commonly used for sample preparation in TXRF analysis. The main goal of the present research was to develop a fast and simple chemical strategy to avoid Hg volatilization during the analysis of wastewater samples by TXRF spectrometry. Three different analytical procedures were tested for this purpose: (i) increasing the viscosity of the wastewater sample by adding a non-ionic surfactant (Triton ® X-114), (ii) Hg immobilization on the quartz reflectors using the extractant tri-isobutylphosphine (Cyanex 471X) and (iii) formation of a stable and non-volatile Hg complex into the wastewater sample. The best analytical strategy was found to be the formation of a Hg complex with thiourea (pH = 10) before the deposition of 10 μL of sample on the reflector for following TXRF analysis. Analytical figures of merit such as linearity, limits of detection, accuracy and precision were carefully evaluated. Finally, the developed methodology was applied for the determination of Hg in different types of wastewater samples (industrial effluents, municipal effluents from conventional systems and municipal effluents from constructed wetlands).

Mercury(II) removal using polymer inclusion membranes containing Cyanex 471X

AbstractBACKGROUND: Regulatory controls to limit mercury emissions in waters have impacted on the development of membrane extraction‐based methodologies for its separation. The specific advantages (effective carrier immobilization, easy preparation, versatility, and good mechanical properties) of polymer inclusion membranes (PIMs) make them suitable for this purpose. In this work a novel procedure using PIMs for mercury separation with a commercial available extractant (Cyanex 471X) is described and evaluated through the determination of the efficiency parameters (permeability, selectivity, stability) and membrane characterization.RESULTS: Using a membrane composed of 30% cellulose triacetate (CTA), 60% 2‐nitrophenyl octyl ether (NPOE), and 10% w/w Cyanex 471X a 0.1 mmol dm−3 Hg(II) solution prepared in 0.01 mol dm−3 HCl was transported to a 0.05 mol dm−3 NaCl solution at pH 12.3 with permeability values in the feed and strip phases of 0.25 and 0.15 cm min−1, respectively. A diffusive Fickian‐type mechanism was inferred from the results. High separation factors ranging between 2 and 5900, less than 11% of competing metal ions transported, active transport of the metal ion and a successful reuse of the PIM were achieved.CONCLUSION: Optimized PIMs using Cyanex 471X represent an interesting alternative for Hg(II) removal from waters showing high efficiency factors and easy implementation. Copyright © 2009 Society of Chemical Industry

The separation of cadmium from zinc with a synergistic mixture of nonylsalicylic acid and triisobutylphosphine sulphide

Metal pH 50 and ΔpH 50 values were determined and compared for a number of organic systems to select a synergistic system for the separation of Cd from Zn. The largest ΔpH 50(Zn–Cd) value was obtained with HRJ-4277 (nonylsalicylic acid)/Cyanex 471X (triisobutyl phosphine sulphide or TIBPS) system and reached 1.53 pH units, indicating excellent separation of Cd from Zn with this system. Shellsol 2046 was chosen as the diluent of the system due to its larger ΔpH 50(Zn–Cd) and excellent phase separation compared with other diluents. Distribution isotherms and subsequent McCabe–Thiele diagrams indicate that 99% Cd could be extracted in two stages at pH 3.80 and A / O ratio of 1.5 : 1. The extraction kinetics and stripping kinetics of Cd and Zn were very fast with > 97% metal transferred within 30 s. In a three-stage batch continuous extraction test, > 99% Cd and 0.4% Zn were extracted. The loaded organic solution contained 3.87 g/L Cd and only 12 ppm Zn. In a two-stage batch continuous scrubbing test, all the co-extracted Zn was removed with the scrubbed organic containing < 1 ppm Zn. Nearly 99% of cadmium was stripped in two batch contacts with 20 g/L sulphuric acid. Excellent separation of Cd and Zn can be achieved in three stages of extraction, two stages of scrubbing and two stage of stripping with this synergistic SX system.

Three-phase contactor with distributed U-shaped bundles of hollow-fibers for pertraction

Pertraction of dimethylcyclopropanecarboxylic acid (DMCCA) and phenol in a new hollow-fiber (HF) contactor of three liquid phases with distributed U-shaped bundles of microporous HF was studied. Trioctylamine (TOA), Hostarex A327 and Cyanex 471X have been used as carriers. The performance of this contactor is similar to other HF contactors. Its advantage is that both bundles of fibers can elongate without deformation of fibers and maldistribution of fibers in the bundles. Pulsation of the membrane phase increases the transport rate by 35–61% and it reaches a plateau value at the pulsation velocity of about 1.1 mm s −1. With increasing velocity of the feed in the fiber lumen the value of the overall mass-transfer coefficient increases, but soon a steady value is approached at the velocity of about 5.5 cm s −1. The diffusion resistances in a series model do not describe the pertraction of DMCCA well. The suggested new diffusion-reaction model, considering the resistance based on the kinetics of the stripping reaction, fits experimental data well. Not only the rate of the acid–carrier complex decomposition, but also that of the DMCCA dimer decomposition have to be considered. The estimated values of the apparent reaction rate constant were for the membrane with TOA 1.91×10 −6 m s −1 and for pure n-alkanes 5.78×10 −6 m s −1. The kinetic resistance on the stripping interface represents 20–60% of the overall mass-transfer resistance and its value is comparable to the diffusion resistance of the both walls.

Pertraction of silver with octylphenylsulfide as carrier in a hollow fiber contactor

The co-transport of silver from nitric acid solutions across a bulk liquid membrane (BLM) in a HF contactor and across a layered BLM with a new carrier octylphenylmethane-sulfide (MF18) have been studied. The transport rate of silver through a BLM containing the MF18 in the HF contactor is much lower comparing with the carrier Cyanex 471X what is connected with a lower value of the distribution coefficient of Ag for MF18. With increasing concentration of the carrier MF18 in the BLM the transport rate of Ag increases what is quite different for Cyanex where the flux do not change with the carrier concentration. This is connected with faster kinetics of the Ag- MF18 complex decomposition.

Transport of mercury(II) ion through a supported liquid membrane containing a triisobutylphosphine sulfide (Cyanex 471X) as a mobile carrier

AbstractCarrier‐facilitated transport of mercury(II) against its concentration gradient from aqueous 0.1 mol dm−3 hydrochloric acid solution across a flat‐sheet supported liquid membrane (SLM) containing triisobutylphosphine sulfide (Cyanex 471X) as the mobile carrier in kerosene as diluent has been investigated. Dilute sodium thiocyanate solution (0.11 mol dm−3) was the most efficient stripping agent among several aqueous reagents tested. Various parameters such as stirring rate, concentration of HCl in the feed solution, concentration of NaSCN in the strippant, concentration of Cyanex 471X in the membrane, and contact time were investigated. Under optimum conditions the transport of Hg(II) across the liquid membrane is about 100% after 6 h. The carrier, Cyanex 471X, selectively and efficiently transported Hg(II) ions in the presence of other associated metal ions. The method has been demonstrated to recover selectively mercury from waste samples and mercurochrome solution.© 2002 Society of Chemical Industry

Extraction behaviour of gold(III) from bromide media using some neutral organophosphine extractants

Organophosphine compounds form strong complexes with Au I I I . This behaviour has been studied as a function of different variables, such as hydrobromic acid concentration, reagent concentration and effect of temperature with Cyanex-921, 923, 925 and 471X in toluene from bromide media. The extraction is observed with Cyanex-921, 923 and 925 in toluene from 4.0 to 6.0 M HBr media, while with Cyanex-471X in toluene from 1.0 to 4.0 M HBr media. The extraction reaction with Cyanex 471X is endothermic, while that with Cyanex-921, 923 and 925 is exothermic in nature. The extraction phenomenon seems to depend upon the donor atom present in the extractant. The methods developed are successfully applied for analysis of gold in real samples.

Comparative study of the determination of platinum by extraction with Cyanex 923 and Cyanex 471X from bromide media

AbstractThe extraction equilibrium study of Pt(IV) was carried out with Cyanex 923 and Cyanex 471X in toluene from hydrobromic acid media to investigate their extraction capacity, since they have different donor atoms, ‘O’ and ‘S’. Their distribution equilibria were studied as a function of extractant concentration, diluents, hydrobromic acid concentration and the effect of temperature on extraction. Pt(IV) was quantitatively extracted with 0.1 mol dm−3 Cyanex 923 in toluene from 5.0–8.0 mol dm−3 HBr media and was stripped with 4.0 mol dm−3 perchloric acid. However it was also quantitatively extracted with 0.1 mol dm−3 Cyanex 471X (with 0.1 mol dm−3SnCl2) in toluene from 6.0–8.0 mol dm−3 HBr media and was stripped with 1.0 mol dm−3 stabilized sodium thiosulfate solution at pH 9.0. The slope analysis method indicated metal complex species of 1:1 for Pt(IV) with Cyanex 923 and Cyanex 471X in toluene from HBr media. These methods were successfully applied to the analysis of platinum in real samples.© 2001 Society of Chemical Industry

Cyanex 471X as extractant for the recovery of Hg(II) from industrial wastes

The extraction of Hg(II) from hydrochloric acid solutions has been investigated using Cyanex 471X in xylene as an extractant. The results demonstrate that Hg(II) is extracted into xylene as HgCl 2·4L (L represents the extractant). The effect of the nature of the diluent on the extraction of Hg(II) with Cyanex 471X has been studied and correlated with the dielectric constant. The loading capacity of the extractant was also determined. IR spectral studies of the extracted complex were used to further clarify the nature of the extracted complex. The potential of the extractant for decontaminating mercury from the brine sludge of a Chlor-Alkali plant has been assessed.