Separation Factor Of CO Research Articles

Selective Separation of Cobalt Ions from Some Fission Products Using Synthesized Inorganic Sorbent

In this work, the separation of Co(II) ions from some fission products using zirconium molybdo silicate (ZrMoSi) sorbent was studied. ZrMoSi sorbent was prepared by the co-precipitation method and characterized using different analytical tools such as FT-IR, SEM, XRF, XRD, TGA, and DTA. ZrMoSi sorbent was found to have the molecular formula ZrO2.MoO3(0.1).SiO2(10.2).4.3 H2O. The sorption behavior of Co(II) involves the effect of shaking time, pH, initial Co(II) concentrations, desorption, and recycling. The sorption data is dependent on pH and ZrMoSi has high separation factors for Co(II) from Cs(I) and Sr(II). Reaction kinetics follow the pseudo-2nd-order model with an equilibrium time of 60 min and sorption isotherms are more applicable to a Langmuir isotherm. Desorption of Co(II) from the loaded sorbent was studied using different eluents and the best eluant is HCl (93.39%). The recycling results of Co(II) from aqueous solutions are excellent and revealed that ZrMoSi sorbent can be used as a promising sorbent to remove Co(II) from liquid waste.

Synthesis of Co(OH)2/poly(MMA-St-APEG) mixed matrix membranes by in-situ microemulsion polymerization for pervaporation separation of benzene/cyclohexane mixture

Aiming to construct mixed matrix membranes (MMMs) with high performance for separating benzene/cyclohexane hydrocarbons, small-sized Co(OH)2 nanoparticles (less than 10 nm of size) were first prepared in reverse microemulsion micelles by using allyloxypolyethyleneglycol(APEG) as a surfactant and methyl methacrylate-styrene (MMA-St) mixture as an oil phase. Next, Co(OH)2/Poly(MMA-St-APEG) MMMs were fabricated via in-situ microemulsion polymerization. Scanning electron microscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy were employed to explore the morphology and structure of Co(OH)2 nanoparticles and their resulting MMMs. Results showed that the protection of micelles during polymerization caused Co(OH)2 nanoparticles to have good distribution in the polymeric matrix. The well-distributed Co(OH)2 nanoparticles in MMMs could interact with benzene molecules by π-π combination, which enhanced the separation performance of MMMs for benzene in the swelling and pervaporation experiments. The activation energy required for benzene to pass through MMMs, including well-distributed Co(OH)2 nanoparticles, was significantly less than that for cyclohexane. Introducing more well-distributed Co(OH)2 nanoparticles further improved the benzene separation performance of MMMs. However, the improvement on the benzene separation performance was weakened when serious agglomeration of nanomaterials occurred in MMMs. The best membrane flux and separation factor of Co(OH)2/poly(MMA-St-APEG) MMMs were approximately 800 g·m−2·h−1 and 12.5, respectively.

Metal Doping Silicates as Inorganic Ion Exchange Materials for Environmental Remediation

Environmental remediation of hazardous metals like Cd(II), and Co(II) ions is very necessary due to their toxicity at trace and accumulation levels in the biosystem. In this study, the sorption of Co(II), and Cd(II) ions from aqueous solutions onto titano-silicate (TiSi) ion exchange material and in-situ dopping composites cobalt titano-silicate (Co-TiSi) and cadmium titano-silicate (Cd-TiSi) was achieved. TiSi and in-situ dopping composites were obtained by precipitation technique and characterized using different analytical tools such as FT-IR, XRD, TGA&DTA, and XRF. Results obtained from this study showed that the capacity for Co(II), and Cd(II) ions revealed that Co-TiSi and Cd-TiSi is a higher capacity than those obtained for TiSi by 1.81, and 1.41 times value, respectively. The distribution coefficients for Co-TiSi as a function of HNO3 have high separation factors for Co(II) at different HNO3 concentrations. Langmuir isotherm model is the most representative for discussing the sorption process with a maximum sorption capacity of 16.02, and 10.96 mg/g for Co(II), and Cd(II) ions, respectively. Co-TiSi is suitable for the column technique for the recovery of studied cations. The investigation proved that a Co-TiSi exchanger is suitable for the uptake of the studied ions from liquid solutions and could be considered as potential material for the refining of effluent polluted with these ions.

Fatty acid methyl esters from catfish oil as a potential diluent for separation of Co(II) and Li(I) from spent lithium-ion batteries by solvent extraction

ABSTRACT Fatty acid methyl esters (FAME) derived from catfish oil, were investigated for its potentiality as friendly substitute for commercial petroleum-based organic diluents to extract Co(II) over Li(I) from the simulated leaching solution using tris-2-ethylhexylamine (TEHA). The results showed that TEHA-in-FAME diluent exhibited higher extraction efficiency of Co(II) and higher separation factor of Co(II) and Li(I) compared to the commercial diluents including kerosene, toluene, and hexane. About 97% of Co (II) from the simulated leaching solution containing Li(I) were obtained in counter-current extraction and stripping experiments by TEHA-in-FAME using dilute HCl solutions. The extraction capacity of the regenerated TEHA-in-FAME was almost unchanged after five recycling stages of extraction and stripping processes, indicating that FAME was an effective diluent for replacement of the commercial diluents.

Separation of cobalt and lithium from spent lithium-ion battery leach liquors by ionic liquid extraction using Cyphos IL-101

The eventual fading and scrapping of lithium (Li)-ion batteries will result in the formation of a huge urban mine of spent batteries. Hydrometallurgy and further extraction/separation are effective ways in which to recover the valuable metal ions from such batteries. Herein, extraction and recovery of spent lithium cobalt oxide (LiCoO2) battery leach liquors using Cyphos IL-101 is proposed. Based on the optimization of extraction conditions, continuous circulating extraction, and thermodynamic analysis, Cyphos IL-101 effectively extracted cobalt (Co) ions with excellent stability and high extraction capacity (35.25 g/L). The separation factor of Co and Li (βCo/Li) was 102.11 in 0.5 M HCl at 60 °C under the optimal operation condition. Moreover, an increase in temperature increased Co extraction in the spent Li-ion battery leach liquors. The extractants before and after use were characterized using ultraviolet-visible (UV–Vis) absorption spectra, Fourier transform infrared (FTIR) spectra, and nuclear magnetic resonance (NMR) spectra. The extraction mechanism of cobalt ions by Cyphos IL-101 was suggested as that cobalt transferred to the organic phase from the aqueous phase in the form of [CoCl4]2−. 90.5% of Co and 86.2% of Li were recovered by precipitation after extraction separation in the forms of cobalt oxalate and lithium carbonate with the purity 87.4% and 74.2%. This suggested method might provide a promising strategy for recycling spent lithium cobalt oxide batteries.

Separation behavior of nickel and cobalt in a LiCl-KCl-NiCl2 molten salt by electrorefining process

Among metal waste generated during the dismantling of a nuclear power plant, the steam generator, which is the main component of nickel alloy contaminated by Co-60, is classified as large-scale waste. Therefore, for the decontamination of cobalt in a contaminated nickel alloy, the separation behavior of nickel and cobalt in a LiCl-KCl molten salt containing NiCl2 was investigated at 550 °C. Cyclic voltammetry (CV) measurements were recorded for determining the electrochemical properties of Ni and Co in molten salt. As CoCl2 was added into the salt, the reduction peak of cobalt was observed. However, the oxidation peak of cobalt could not be observed owing to the dissolution of the cobalt resulting from the chemical reaction with NiCl2. The highest separation factor of Co to Ni was calculated to be 1394 when the Ni2+/Co2+ ratio was 4, which indicated that Ni and Co can be separated. Therefore, the possibility of its application in the radioactive waste of Ni alloys from a steam generator via electrorefining using molten salt technology was confirmed.

Determination of distribution ratios of Zr(IV), Co(II), Sb(V) and Nb(V) using polyaniline in acid solutions

In this work, we report the distribution ratios of Zr(IV), Co(II), Sb(V) and Nb(V) using polyaniline in HCl, HF, oxalic acid and HF + HCl solutions. Distribution ratios were determined by batch method using radiotracer technique. Further, the separation factors and the %-uptake of metal ions were calculated and compared. Among the media studied, separation factors for Co(II), Sb(V) and Nb(V) with respect to Zr(IV) were the highest in 1 M HCl and the values are 52, 108 and 404 respectively. The results of this study can be utilized for designing an ion-exchange process for the decontamination of zircaloy pressure tubes used in the Pressurized Heavy Water Reactors.

Solvent Extraction of Co, Ni and Mn from NCM Sulfate Leaching Solution of Li(NCM)O2 Secondary Battery Scraps

AbstractAs a part of the study on recycling Li(NCM)O2lithium-ion battery scraps, solvent extraction experiments were performed using different extraction agents such as PC88A, Cyanex272 and D2EHPA to separate Co, Ni and Mn from the leaching solution. When the ratio of Mn to Ni was about 0.4 in the leaching solution, the separation factor for Co and Mn was found to be less than 10 so that the separation of Co and Ni was insufficient. When solvent extraction was done using the solution with the lower Mn/Ni ratio of 0.05 where Mn was removed by potassium permanganate and chlorine dioxide, more than 99% of Mn could be extracted through five courses of extraction using 30vol% D2EHPA while the extraction rates of Co and Ni were around 17% and 11%, respectively. In the case that Mn was removed from the solution, the extraction rate of Co was higher than 99% whereas less than 7% Ni was extracted using Cyanex272 suggesting that Co and Ni elements were effectively separated.

Selective separation of cobalt and nickel by flat sheet supported liquid membrane using Alamine 300 as carrier

Cobalt and nickel are among the most important nonferrous metals. The using of flat sheet supported liquid membranes (FSSLMs) to remove metals from wastewaters has been used actively by the scientific and industrial communities. In this study, the selective separation of cobalt from thiocyanate solutions containing cobalt and nickel by FSSLM was examined using tri-n-octylamine (Alamine 300) as carrier. The FSSLM was consisted of extractant, flat sheet support and organic solvent. The various parameters were studied to determine the optimum extraction and striping conditions of cobalt and nickel. These parameters were stirring speeds of phases, NH4SCN concentration, pH, diluent type, extractant concentration, stripping reagent concentration and modifier concentration. Concentration of cobalt and nickel were determined by Shimadzu AA-6701GF spectrophotometer. In the optimum conditions, selective separation of cobalt was achieved with an efficiency of 98.4% within 8h, for equimolar feed mixtures, 400mg/L Co+400mg/L Ni, and the separation factor of Co(II) over Ni(II) was 234.4. In addition, for nonequimolar feed mixtures, 500mg/L Co+1000mg/L Ni, Ni in excess, selective separation of cobalt was 99.9%, and the separation factor of Co was 506 in the same time.

Co3(HCOO)6 Microporous Metal–Organic Framework Membrane for Separation of CO2/CH4 Mixtures

Continuous metal-organic framework-type Co(3)(HCOO)(6) intergrown films with a one-dimensional zigzag channel system and pore aperture of 5.5 Å are prepared by secondary growth on preseeded macroporous glass-frit disks and silicon wafers. The adsorption behavior of CO(2) or CH(4) single gases on the Co(3)(HCOO)(6) membrane is investigated by in situ IR spectroscopy. It is shown that the isosteric heats of adsorption for CO(2) (17.7 kJ mol(-1)) and CH(4) (14.4 kJ mol(-1)) do not vary with increasing amount of adsorbed gases. The higher value of isosteric heat for CO(2) is an indication of the stronger interaction between the CO(2) and the Co(3)(HCOO)(6) membrane. The Co(3)(HCOO)(6) membrane is studied by binary gas permeation of CO(2) and CH(4) at different temperatures (0, 25, and 60 °C). The membrane has CO(2)/CH(4) selectivity with a separation factor higher than 10, which is due to the unique structure and molecular sieving effect. Upon increasing the temperature from 0 to 60 °C, the preferred permeance of CO(2) over CH(4) is increased from 1.70×10(-6) to 2.09×10(-6) mol m(-2) s(-1) Pa(-1), while the separation factor for CO(2)/CH(4) shows a corresponding decrease from 15.95 to 10.37. The effective pore size of the Co(3)(HCOO)(6) material combined with the pore shape do not allow the two molecules to pass simultaneously, and once the CO(2) molecules are diffused in the micropores, the CH(4) is blocked. The supported Co(3)(HCOO)(6) membrane retains high mechanical stability after a number of thermal cycles.

Cobalt and Nickel Recovery from Sulfate Media Containing Calcium, Manganese, and Magnesium with a Mixture of CYANEX 301 and a Trialkylamine

Data are presented on the solvent extraction of nickel and cobalt from sulfate solutions imitating the composition of partially neutralized liquors from the leaching of oxidized nickel ores using mixtures of 0.4 M CYANEX 301 (HR) with 0.4–0.5 M C7–C9 fraction of a trialkyl amine (R′3N) as the extractant. Nickel and cobalt are efficiently extracted in the pH range 6.2–6.5 and separated from Mn, Mg, and Ca in the extraction step. The separation factors for Co and Ni are high (102–103). Due to the formation of the stable adduct [R′3NH]+[R]− between the extractant components, nickel and cobalt can be stoichiometrically stripped with H2SO4 (1.0–2.0 M), allowing the production of concentrated solutions (> 100 g/L of total Co and Ni). The nickel strip liquors contain only a small amount of free acid (pH 1.5–2.0) after purification from cobalt, so they can be further processed using traditional technologies. A proposed flowsheet for nickel and cobalt recovery from such leach liquors has the advantages of ease of production of concentrated nickel and cobalt strip liquors in sulfate media and the stability of the extractant and strip liquor to oxidation by air or oxygen compared to other variants of CYANEX 301 applications.

Synergistic separation of Co(II)/Li(I) for the recycling of LIB industry wastes by supported liquid membrane using Cyanex 272 and DR-8R

The separation of Co(II) and Li(I) from simulated solution of lithium ion battery (LIB) industry wastes has been studied by a supported liquid membrane (SLM) process. The synergistic effect of mixture of the extractants Cyanex 272 and DP-8R on the permeation rate and separation factor of Co(II) and Li(I) from dilute aqueous sulfate media using a supported liquid membrane (SLM) technique has been examined. A microporous hydrophobic PVDF film was used as the solid support for the liquid membrane. The extractants Cyanex 272 and DP-8R and mixture of those were used as mobile carriers. The effects of different parameter such as stirring speed, pH of the feed solution, extractant concentration in the membrane phase, Co(II)/Li(I) concentration in the feed solution, and H 2SO 4 strip acid concentration, on Co(II) flux ( J Co(II)) and Li(I) flux ( J Li(I)) have been studied and compared. For all of the systems studied, Co/Li are optimally separated in the acidic pH region of 5.0−6.0. The best separation factor of 497 was achieved at pH 5.00 using a mixture of Cyanex 272 and DP-8R at a concentration of 750 mol/m 3 in the membrane phase, a strip acid concentration of 100 mol/m 3, and a stirring speed of 350 rpm. The separation factors for all three systems under the respective optimum experimental conditions have been calculated and compared. Qualitatively, they follow the order: mixed-extractant system > Cyanex 272 > DP-8R. This sequence may be quantitatively expressed as: mixed-extractant system ≈ 3 × Cyanex 272 ≈ 15 × DP-8R.

Preparation and characterization of carbon molecular sieve membranes for gas separation—the effect of incorporated multi-wall carbon nanotubes

A new class of multi-wall carbon nanotubes (MWCNTs)/carbon nanocomposite thin films was successfully prepared by incorporating (MWCNTs) into polyimide (PI) precursor solution. The carbon films were obtained in only one coating step by spin-coating technique on a macroporous alumina substrate and were pyrolyzed at 773 K. The structure and single gas permeation properties of PI-based carbon membranes incorporated with or without MWCNTs were investigated. From the FE-SEM images, the pure carbon membranes have a thin dense permselective layer with few closed pores while the permselective layer of the MWCNTs/carbon nanocomposite thin films are porous due to the structure of nanotubes. The MWCNTs/carbon nanocomposite thin films exhibited that the ideal carbon dioxide flux was 866.6 Barrer (1 Barrer = 1×10 −10 cm 3 (STP) cm cm −2 s −1 cm Hg −1) and the separation factor of CO 2/N 2 was 4.1 at room temperature and 1 atm, which was 2–4 times of magnitude higher than that of pure carbon membrane prepared by the same procedures and conditions.

Carbon dioxide separation from hydrogen and nitrogen: Facilitated transport in arginine salt–chitosan membranes

CO 2-selective membranes that obtain high CO 2 permeabilities accompanied with high CO 2/H 2 and CO 2/N 2 separation factors at industrial temperatures and pressures are applicable to fuel cell operations and flue gas purification. This paper describes the separation of carbon dioxide from a mixed gas stream of hydrogen and nitrogen by a chitosan membrane containing 40 wt% sodium arginate. Continuous membrane separations were done for a feed gas with 10% carbon dioxide, feed gas total pressures of 152 and 507 pa (1.5 and 5 atm), and temperatures ranging from 20 to 150 °C. The addition of arginine salts increases the number of amino groups for facilitated transport of CO 2 and increases the water levels in the arginine salt–chitosan membranes compared to swollen chitosan membranes at the same humidification conditions. At 152 pa (1.5 atm) feed pressure and 110 °C, there are maxima in the carbon dioxide permeabilities (1500 barrers), and the separation factors for CO 2/N 2 (852) and CO 2/H 2 (144). At higher pressure (507 pa (5 atm)), there were no maxima in the carbon dioxide permeabilities or separation factors, and there was less bound water in the membrane.

Equilibrium and kinetic analysis of CO 2–N 2 adsorption separation by concentration pulse chromatography

CO 2 and N 2 adsorption kinetics and equilibrium behaviours have been studied with silicalite, NaY and 13X by using concentration pulse chromatography for the separation of these gases in the present study. Adsorption Henry's Law constants, the heat of adsorption values, micropore diffusion coefficients and corresponding activation energies are determined experimentally and the three different mass transfer mechanisms are discussed. From the equilibrium data, the corresponding separation factors are obtained for the adsorption separation processes. The heat of adsorption values as well as the Henry's Law adsorption equilibrium constants of CO 2 are much higher than those of N 2 for all the adsorbents studied. 13X, NaY and silicalite all have good separation factors for CO 2/N 2 system based on equilibrium processes. The order of the equilibrium separation factors is 13X (Ceca) > 13X (Zeochem) > NaY (UOP) ≫ silicalite (UOP). Equilibrium selectivity favours CO 2 over N 2. Micropore diffusion resistance is the definite dominant mass transfer mechanism for CO 2 with silicalite and NaY.

Separation of Co(II) and Li(I) by supported liquid membrane using Cyanex 272 as mobile carrier

The permeation rate of Co(II) and Li(I) from a dilute aqueous sulfate media using supported liquid membrane (SLM) technique has been studied. The microporous hydrophobic PVDF film was used as the solid support for the liquid membrane and Cyanex 272 was used as mobile carrier. The liquid–liquid extraction of Co(II) and Li(I) using Cyanex 272 in sulfate media was studied and compared with supported liquid membrane results. Effect of different parameters such as speed of rotation, pH in feed solution, Cyanex 272 concentration in membrane phase, Co(II) and Li(I) concentration in feed solution and strip acid concentration on Co(II) flux J Co(II) and Li(I) flux J Li(I) has been studied. The Co(II) flux increased with increasing of pH from 4.00 to 6.00 and then decreased with further increase of pH up to 6.75. The Co(II) flux J Co(II) was also increased with increase of Cyanex 272 concentration in membrane phase up to 750 mol/m 3 then decreased. The flux for Li(I) was remained constant. The separation factors for Co(II) and Li(I) were calculated at different experimental condition and were reported. At suitable optimum condition of pH 6.00, Cyanex 272 concentration in membrane phase of 750 mol/m 3, strip acid concentration of 25 mol/m 3 and stirring speed of 5.83 Hz (350 rpm), the flux for Co(II) J Co(II) was 82.20 × 10 −6 mol/m 2 s and the flux for Li(I) J Li(I) was 0.918 × 10 −6 mol/m 2 s.

Novel preparation of NaA/carbon nanocomposite thin films with high permeance for CO 2/CH 4 separation

Novel NaA/carbon nanocomposite thin films were successfully prepared on a porous α-Al 2O 3 substrate by incorporating nanosized NaA zeolite into novolak-type phenolic resin. The prepared films were characterized by XRD, SEM and single gas permeation tests. The NaA zeolite/carbon nanocomposite thin films exhibited that the ideal separation factor of CO 2/CH 4 was 28.4 and the carbon dioxide flux was 3.39 × 10 −7 mol/(Pa m 2 s) at room temperature and under a pressure difference of 100 kPa, which was two orders of magnitude higher than that of pure carbon membrane prepared at the same procedures and conditions as those of composite films. From the SEM images, the films were continuous and highly intergrown. Compared with carbon membranes, the thickness of nanocomposite films was drastically decreased, which was helpful to reduce the diffusion resistance and increase the flux of gas permeance.

A combinatorial dynamic Monte Carlo approach to finding a suitable zeolite membrane structure for CO 2/N 2 separation

Dynamic Monte Carlo (DMC) simulations have been performed to estimate the perm-selectivity of binary mixtures (CO 2/N 2) in zeolite-like porous membranes. Various hypothesized porous structures, including a previously reported zeolite structure, were used to calculate the separation factor and permeability of CO 2/N 2. The rate coefficient for hopping between the adsorption sites used in the DMC calculation was estimated based on an empirical atomic force field. The membranes that have the structure of both a seven-membered ring (7MR) (0.34 nm) pore diameter and larger size of adsorption site with high dimensionality in pore architecture were shown to have a high separation factor for CO 2. This simulation technique is proposed as a new methodology to search for the optimal structure of porous membranes for a specific given separation system. The advantage of this strategy of simulation is the reasonable calculation time compared with conventional techniques such as non-equilibrium molecular dynamics.

NaA zeolite/carbon nanocomposite thin films with high permeance for CO 2/N 2 separation

Novel NaA zeolite/carbon nanocomposite thin films were successfully prepared on a porous α-Al 2O 3 substrate by dip-coating method. The prepared films were characterized by XRD, SEM and single gas permeation tests. NaA zeolite/carbon nanocomposite thin films exhibited the ideal separation factor of CO 2/N 2 of 6.04 with the carbon dioxide permeance of 3.39 × 10 −7 mol Pa −1 m −2 s −1 at room temperature and 100 kPa, which was two orders of magnitude higher than that of pure carbon membrane reported by previous literature. The observed adsorption isotherms indicated that the incorporation of zeolite NaA crystal improved the CO 2 adsorption ability of carbon materials, and decreased its N 2 adsorption ability. The ideal permselectivity of CO 2/N 2 of carbon/NaA composite films was 6.04, higher than the ideal adsorption selectivity, probably because the small molecule of CO 2 diffused faster than N 2. From the SEM images, the thickness of nanocomposite films was 1–2 μm, which was helpful to decrease the resistance and increase the flux of gas permeance.

Gas permeation and separation properties of sulfonated polyimide membranes

Permeability and selectivity of pure gas H 2, CO 2, O 2, N 2 and CH 4 as well as a mixture of CO 2/N 2 for sulfonated homopolyimides prepared from 1,4,5,8-naphthalene tetracarboxylic dianhydride (NTDA) and 2,2-bis[4-(4-aminophenoxy)phenyl] hexafluoro propane disulfonic acid (BAPHFDS) were measured and compared to those of the non-sulfonated homopolyimide having the same polymer backbone. The polyimide in a proton form (NTDA–BAPHFDS(H)) displayed higher selectivity of H 2 over CH 4 without loss of H 2 permeability. Strong intermolecular interaction induced by sulfonic acid groups decreased diffusivity of the larger molecules. The CO 2/N 2 (19/81) mixed gas permeation was investigated as a function of humidity. With increasing relative humidity from 0% RH to 90% RH, the CO 2 permeability for NTDA–BAPHFDS(H) polyimide increased by more than one order of magnitude, and the selectivity of CO 2/N 2 also increased twice or more. On the other hand, the gas permeability for the non-sulfonated polyimide slightly decreased with increasing humidity. NTDA–BAPHFDS(H) polyimide displayed a CO 2 permeability of 290×10 −10 cm 3 (STP) cm/(cm 2 s cmHg) and a separation factor of CO 2/N 2 of 51 at 96% RH, 50 °C and total pressure of 1 atm.