Determined Distribution Coefficients Research Articles

Mechanism of astatine and bismuth sorption on extraction chromatography resins from nitric acid media

Systematic study of astatine (At) sorption on extraction chromatography resins from nitric acid media has been performed at Texas A&M University. This work covers commercially available resins such as LN, TK400, SR, TRU, and UTEVA. Acquiring an understanding of At behavior in up to 4 M HNO3 solutions is a key step to develop a rapid and reliable system for At separation and purification. The determined distribution coefficients are greater than 20 for all the resins studied, reaching 400 for TRU and UTEVA resins. The sorption uptake decreases in the order: TRU ≳ UTEVA > TK400 ≳ SR > LN. For each resin a thermodynamic model has been developed to suggest a possible mechanism of At sorption and corresponding sorption constants have been estimated. Literature data along with new results on bismuth (Bi) sorption by studied resins in nitric acid media have been reviewed and a mathematical model to describe its behavior has been suggested. A ratio of corresponding fit functions of At and Bi assigned to the same resin and acidity has been used to estimate separation factors of these elements. Only the TRU resin is not suitable for efficient At isolation from Bi, while the other four resins demonstrate promising results.

Insights into the liquid extraction mechanism of actual high-strength phenolic wastewater by hydrophobic deep eutectic solvents

Liquid-liquid extraction using recently developed hydrophobic deep eutectic solvents (HDESs) shows great potential for the removal of phenol from wastewater. But most of the research limited themselves by being focused on the wastewater with phenol concentration lower than 1000 mg·L−1 and most importantly, the extraction mechanism is still lacking in deep understanding. We pilot to remove phenol from actual industrial wastewater containing ultra-high-concentration phenol (∼54,000 mg·L−1) using HDESs, and also carried out a systematic investigation on their extraction mechanism. Eight HDESs composed of dl-menthol (hydrogen bond acceptor, HBA) and various fatty acids (hydrogen bond donor, HBD) were synthesized and the effects of various important conditions, such as HBA/HBD molar ratio, HDES/wastewater mass ratio, and initial concentration of phenol in wastewater, on their extraction efficiencies were evaluated. The experimental results showed that all the prepared HDESs possess excellent extraction capacity for phenol with the best one being obtained from dl-menthol/nonanoic acid (C9) based HDES (molar ratio 2:1) within 5 min at room temperature (97 %). Successive extraction was performed to minimize the amount of solvents used for economic consideration. Regeneration and reuse of HDESs after phenol extraction was achieved by activated carbon recovery. The extraction mechanism was investigated experimentally by Fourier transform infrared (FTIR) and 1H nuclear magnetic resonance (NMR) characterization, together with the predicted activity coefficients of phenol in solvents by COSMO-RS model and experimentally determined distribution coefficient (D) between HDES and aqueous phase. The hydrogen bond formed between HDES and phenol during extraction was experimentally identified. Moreover, quantum computation by DFT method was applied to model the extraction process, and the extraction mechanism was investigated more in-depth by theoretical computation. The results of DFT calculation provided good agreement with the experimental data and a new six-membered ring-like structure formed during the extraction process between HDES and phenol molecule was suggested for the first time to the best of our knowledge. We hope this work will provide guidance on the study of liquid extraction process/mechanism using HDESs and promote their practical application in the future.

Time-Dependent Behavior of Waste Lithium-Ion Batteries in Secondary Copper Smelting

As the electrification sector expands rapidly, the demand for metals used in batteries is increasing significantly. New approaches for lithium-ion battery (LIB) recycling have to be investigated and new technologies developed in order to secure the future supply of battery metals (i.e., lithium, cobalt, nickel). In this work, the possibility of integrating LIB recycling with secondary copper smelting was further investigated. The time-dependent behavior of battery metals (Li, Co, Ni, Mn) in simulated secondary copper smelting conditions was investigated for the first time. In the study, copper alloy was used as a medium for collecting valuable metals and the distribution coefficients of these metals between copper alloy and slag were used for evaluating the recycling efficiencies. The determined distribution coefficients follow the order Ni >> Co >> Mn > Li throughout the time range investigated. In our study, the evolution of phases and their chemical composition were investigated in laboratory-scale experiments under reducing conditions of oxygen partial pressure p(O2) = 10−10 atm, at 1300 °C. The results showed that already after 1 h holding time, the major elements were in equilibrium. However, based on the microstructural observations and trace elements distributions, the required full equilibration time for the system was determined to be 16 h.

A newly proposed isotherm model to predict Cs exchange with crystalline silicotitanate in tank waste simulants

ABSTRACT The Zheng Anthony Miller (ZAM) computer model, a multicomponent ion exchange model used to predict the exchange of Group I metals onto crystalline silicotitanate (CST), has historically been used to predict Cs distribution coefficients from Hanford and Savannah River Site (SRS) tank waste simulants. Comparison of experimentally determined Cs distribution coefficients from tank waste simulants with ZAM isotherm model predictions indicate overprediction of Cs and K distribution coefficients for simple and complex simulants with the engineered form of CST. Additionally, recent changes in chemical composition/manufacturing of IONSIV TM R9140-B have resulted in increased Cs capacity from high-salt, highly alkaline solutions. This work served to assess different isotherm models and refine equilibrium parameters to develop a model that can be applied to Hanford and SRS tank waste Cs removal efforts. Toward this goal, the Campbell Westesen Peterson (CWP) model was developed. This model utilized the experimentally determined Cs capacity, and simplified ZAM equilibria expressions to include only the binary substitution of Cs+ or K+ on the Na+ sites. Equilibrium constants for these equations were refined using experimentally determined distribution coefficients. Overall, the CWP model significantly improved our ability to predict both Cs and K loading capacity from complex matrices.

Determining distribution coefficients for low cost adsorbents

AbstractAs with other construction materials, coal fly ash contains trace metals that can leach into the natural environment. As part of a broader effort to encourage appropriate coal combustion product use in infrastructure applications (e.g., road construction, stabilization, and structural fill), this study evaluated traditional and low‐cost adsorbent alternatives for their capacity to attenuate trace metals. Batch sorption tests were used as a preliminary screen for a wide variety of low cost (e.g., steel byproducts, rubber dust, and compost) and innovative materials (e.g., kudzu, biofilm, and pond weed) as well as conventional materials (activated carbon, alumina, and zeolites). The removal rates were demonstrated in this study by observing the calculated distribution coefficient (Kd) which were determined using a program called MATLAB. Limestone and steel byproducts were found to be particularly effective with large Kd values of 15,740, 1,520, and 540 L kg−1 for cadmium, chromium, and selenium and, for ladle refractory and mill scale, Kd values of 3,910, 670, and 1,760 L kg−1 were observed. Among the three metals tested for this study, it was observed that most low cost and innovative materials removed cadmium quite efficiently; however, the removal of selenium and chromium depended on the substrate and prevailing pH. In general, these results suggest that alternative materials may have relevance in niche applications where leaching is a concern that can be addressed through enhanced attenuation capacity via blending or layering of adsorbents.

Estimating the Equilibrium Distribution of Perfluoroalkyl Acids and 4 of Their Alternatives in Mammals.

Perfluoroalkyl acids (PFAAs) mostly exist as ionic compounds that are of major concern because of their accumulative behavior. The discussion about their risk is ongoing considering the increasing production of structurally similar alternatives. We conducted model calculations based on equilibrium distribution coefficients that allow studying the distribution of PFAAs and their alternatives in various mammalian organs through comparison to empirical measurements in humans and rats. The calculations rely on experimentally determined distribution coefficients of a series of PFAAs and 4 of their alternatives to physiological matrices such as structural proteins, storage lipids, membrane lipids, albumin, and fatty acid binding protein (FABP). The relative sorption capacities in each organ were calculated from the combination of distribution coefficients and physiological data. The calculated distribution of PFAAs and alternatives within the organs showed that albumin and membrane lipids and, to a lesser extent, structural proteins have the highest relative sorption capacities for the compounds. Sorption to FABP is only relevant in the distribution of short-chain PFAAs. Storage lipids play a minor role in the distribution of all studied compounds. Our calculated distribution of PFAAs was evaluated by comparison to reported PFAA concentrations in various organs. Environ Toxicol Chem 2021;40:910-920. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Band-selective excitation NMR spectroscopy and quantitative time-domain analysis using Complete Reduction to Amplitude-Frequency Table (CRAFT) to determine distribution coefficients during drug development.

A sensitive quantitative 1 H NMR method for determining distribution or partition coefficients has been developed that is applicable to early drug discovery. After partitioning and equilibration, aliquots from each layer are analyzed using band-selective excitation 1 H NMR spectroscopy in regions that are free of 1-octanol and water solvent signals. Signals are quantitated directly using CRAFT software, and their amplitudes are adjusted to correct for nonuniformity within the excitation band. Using this approach, the distribution coefficients for 20 drugs present at low concentrations were determined giving values that were in excellent agreement with literature values.

Application of an algal growth inhibition assay to determine distribution coefficients of benzalkonium ions between kaolinite and water

Benzalkonium compounds are widely used and found in environmental samples. Due to their amphiphilic nature, it is important to know sorption coefficients to account their bioavailability. However, currently available models describing their partitioning were developed using low molecular weight homologues and it cannot be ascertained whether they are applicable to their higher molecular weight homologues. Reasons for the scarcity of data on highly sorptive compounds include the lack of reliable quantification techniques for analyzing these chemicals at environmentally relevant levels. This study, therefore, reports on an algal growth inhibition assay-based method for the determination of kaolinite/water distribution coefficients for benzalkonium compounds at their environmentally relevant concentration range. Sorption to clay was computed using the difference between median effective concentration determined in a culture with kaolinite and that derived from a culture grown in standard medium. A kinetic model was used to account for uptake into algal cells and to calculate free concentrations. Due to the sensitivity of the algal species, Pseudokirchneriella subcapitata, it was possible to determine distribution coefficients below micromole per liter concentrations. The computed distribution coefficients showed a linear increase with number of carbon atoms in the alkyl chain up to 14. The proposed bioassay-based method should be applicable to determine distribution coefficients for highly hydrophobic chemicals and ionic liquids at a concentration range lower than typical analytical limits.

Experimental Investigation and Thermodynamic Modeling of the Distributions of Ag and Au Between Slag, Matte, and Metal in the Cu–Fe–O–S–Si System

To assist in improving the recoveries of gold and silver in both primary production and metals’ recycling, the distributions of Ag and Au between slag, matte, and metal in the Cu–Fe–O–S–Si system have been investigated using an integrated experimental and thermodynamic modeling approach. The experimental technique involved high-temperature equilibration at selected temperatures and gas atmospheres, and rapid quenching followed up by measurement of phase compositions using microanalysis techniques. Electron probe X-ray microanalysis was used to measure the major element concentrations in the condensed phases. The laser ablation inductively coupled plasma mass spectrum technique was used to measure the concentrations of Ag and Au in slag. The experimentally determined distribution coefficient of Ag between matte and slag decreases with the increasing matte grade below approximately 70% Cu, but then increases with the increasing matte grade between 70 and 80% Cu. The experimentally determined distribution coefficient of Au between matte and slag decrease from log L = − 2.8 for approximately 63% Cu to approximately log L = − 3.8 at 76% Cu. Thermodynamic model parameters describing Ag and Au distributions have been derived following consideration of available data on slag/matte, slag/metal, and slag/matte/metal systems.

Characterization of sorption properties of high-density polyethylene using the poly-parameter linearfree-energy relationships

High-density polyethylene (HDPE) is a known sorbent for non-ionic organic compounds in technical applications. Nevertheless, there is little information available describing sorption to industrial HDPE for a broad range of compounds. With a better understanding of the sorption properties of synthetic polymers, environmental risk assessment would achieve a higher degree of accuracy, especially for microplastic interactions with organic substances. Therefore, a robust methodology for the determination of sorbent properties for non-ionic organic compounds by HDPE is relevant for the understanding of molecular interactions for both technical use and environmental risk assessment.In this work, sorption properties of HDPE material used for water pipes were characterized using a poly-parameter linear free-energy relationship (ppLFER) approach. Sorption batch experiments with selected probe sorbates were carried out in a three-phase system (air/HDPE/water) covering an aqueous concentration range of at least three orders of magnitude. Sorption in the concentration range below 10−2 of the aqueous solubility was found to be non-linear and the Freundlich model was used to account for this non-linearity. Multiple regression analysis (MRA) using the determined distribution coefficients and literature-tabulated sorbate descriptors was performed to obtain the ppLFER phase descriptors for HDPE. Sorption properties of HDPE were then derived from the ppLFER model and statistical analysis of its robustness was conducted. The derived ppLFER model described sorption more accurately than commonly used single-parameter predictions, based i.e., on log Ko/w. The ppLFER predicted distribution data with an error 0.5 log units smaller than the spLFERs. The ppLFER was used for a priori prediction of sorption by the characterized sorbent material. The prediction was then compared to experimental data from literature and this work and demonstrated the strength of the ppLFER, based on the training set over several orders of magnitude.

Effect of Solvent Cation Alkyl-Chain Length on the Separation of Butylbenzene from n-Tetradecane Using Hexafluorophosphate-Based Ionic Liquids at (313.15 and 333.15) K and 101.3 kPa

The extraction of butylbenzene from n-tetradecane using three ionic solvents ([bmim][PF6], [hmim][PF6], and [omim][PF6]) was studied at two temperatures (313.15 and 333.15 K) and under atmospheric pressure (101.3 kPa). Experimentally determined distribution coefficients (K) and solvent selectivities (S) were plotted against the mole fraction of butylbenzene in the solvent phase; improved results were obtained compared to the conventional solvent, sulfolane. The distribution coefficient and selectivity both increased with increasing alkyl chain length of the 1-alkyl-3-methylimidazolium moiety of the solvent cation. The universal quasichemical model was satisfactorily applied for correlating the experimental liquid–liquid equilibrium data of all three systems. Furthermore, comparison with literature results revealed that the distribution coefficients decreased with increasing paraffin carbon number.

Electromigration experiments for studying transport parameters and sorption of cesium and strontium on intact crystalline rock

This study aims to determine upscaling factors for the radionuclides' distribution coefficients (Kd) on crushed rocks to intact rock for the safety analysis of radionuclide migration from spent nuclear fuel in bedrock towards biosphere. Here we report the distribution coefficients for intact rock determined by electromigration sorption experiments and compare the results with those from recently performed batch sorption experiments. In total 34 rock samples, representing three typical rock types from Olkiluoto Finland, were studied in order to determine distribution coefficients, effective diffusion coefficients and porosities using the electromigration sorption experiments, formation factor experiments and porosity measurement. The parameters determined represent the three main parameters of geosphere used in the safety assessment of spent nuclear fuel disposal. The distribution coefficients of cesium and strontium on intact rock varied between (0.12–26.2) × 10−3 m3/kg and (1.4–13.3) × 10−3 m3/kg, respectively, whereas recent results for crushed rock varied between (2–57) × 10−3 m3/kg and (17–40) × 10−3 m3/kg, respectively. This implies that crushing increases the distribution coefficient significantly and upscaling factors from 3 to 33 were determined for scaling the distribution coefficients of crushed rock to ones of intact rock. The determined distribution coefficients of cesium and strontium for intact rock can be directly applied in the safety assessment whereas the upscaling factors can be used to convert distribution coefficients determined for crushed rock into ones for intact rock. Based on the results for porosities and effective diffusion coefficients it was concluded that they do not seem to correlate with sorption parameters. However, an alteration state, heterogeneity and mineral content seem to be important factors affecting the distribution coefficients and upscaling factors.

Formation by silicate–fluoride + phosphate melt immiscibility of REE-rich globular segregations within aplite dikes

Aplite dikes intruding the Proterozoic 1.42(± 3) Ga Longs Peak-St. Vrain Silver Plume-type peraluminous granite near Jamestown, Colorado, contain F, P, and rare earth element (REE)-rich globular segregations, with 40–46% REE, 3.7–4.8 wt% P2O5, and 5–8 wt% F. A combination of textural features and geochemical data suggest that the aplite and REE-rich globular segregations co-existed as two co-genetic liquids prior to their crystallization, and we propose that they are formed by silicate–fluoride + phosphate (+ S + CO2) melt immiscibility following ascent, cooling, and decompression of what was initially a single homogeneous magma that intruded the granite. The REE distribution coefficients between the silica-rich aplites and REE-rich segregations are in good agreement with experimentally determined distribution coefficients for immiscible silicate–fluoride + phosphate melts. Although monazite-(Ce) and uraninite U–Th–Pb microprobe ages for the segregations yield 1.420(± 25) and 1.442(± 8) Ga, respectively, thus suggesting a co-genetic relationship with their host granite, eNd1.42Ga values for the granites and related granitic pegmatites range from − 3.3 to − 4.7 (average − 3.9), and differ from the values for both the aplites and REE-rich segregations, which range from − 1.0 to − 2.2 (average − 1.6). Furthermore, the granites and pegmatites have (La/Yb)N 100 and absence of an Eu anomaly in both the aplites and segregations. These data are consistent with the aplite dikes and the REE-rich segregations they contain being co-genetic, but derived from a source different from that of the granite. The higher eNd1.42Ga values for the aplites and REE-rich segregations suggest that the magma from which they separated had a more mafic and deeper, dryer and hotter source in the lower crust or upper mantle compared to the quartzo-feldspathic upper crustal source proposed for the Longs Peak-St. Vrain granite.

Sorption of Rare-earth Elements and Ac on DN resin with HCl, HClO4, CH3COOH, CCl3COOH

ABSTRACTThe distribution of some rare-earth elements (REE) on DN resin (TODGA loaded resin by Triskem international) was determined from different concentrations of two inorganic (HCl, HClO4) and two organic acids (CH3COOH, CCl3COOH). The separation of Ac from REE is researched, as well as some separation possibilities of the elements within the REE. The determined distribution coefficients allows the prediction of the elution profiles of the researched elements. Using the obtained results in this work further applications can be considered.

Investigation of Extraction of 4-Oxopentanoic Acid by N,N-Dioctyloctan-1-amine in Six Different Diluents: Equilibrium Study

The present equilibrium study deals with the reactive extraction of 4-oxopentanoic acid [levulinic acid] from an aqueous solution by N,N-dioctyloctan-1-amine [tri-n-octylamine (TOA)] at a constant concentration of 0.573 kmol·m–3 in a wide range of diluents such as [n-decane, decane-1-ol, n-decane + decane-1-ol (1:1 v/v), toluene, 4-methylpentan-2-one (MIBK), and dichloromethane (DCM)] at isothermal conditions ((298 ± 1) K). The physical extraction of levulinic acid with pure diluents is also carried out. The effect of acid concentration (0.10 mol·kg–1 to 0.75 mol·kg–1) and type of diluent on the recovery of levulinic acid from aqueous solution are determined. Mathematical modeling based on mass action law is used to estimate overall equilibrium constants (KE), stoichiometry of reaction, and individual equilibrium constants (K11 and K21) for 1:1 and 2:1 complexes between acid and TOA. Further, the experimentally determined distribution coefficients (KD) are correlated predicted ones by the linear solvation...

English

A simple method has been developed for the preconcentration of Mercury(II) [Hg(II)] based on the adsorption of its histidine functionalized multi-walled carbon nanotubes (MWCNTs-His) complex. The stability of a chemically MWCNTs-His were determined especially in concentrated hydrochloric acid which was then used as a recycling and pre-concentration reagent for further uses of MWCNTs-His. The application of this MWCNTs-His for adsorption of a series of metal ions was performed by using different controlling factors such as the pH of metal ion solution and the equilibration shaking time by the static technique. Hg(II) was found to exhibit the highest affinity towards extraction by these MWCNTs-His phases. The pronounced selectivity was also confirmed from the determined distribution coefficient (Kd) of all the metal ions, showing the highest value reported for Hg(II) to occur by MWCNTs-His. The potential applications of MWCNTs-His for selective extraction of Hg(II) to occur from aqueous solution were successfully accomplished as well as pre-concentration of low concentration of Hg(II) (40 pg ml-1) from natural tap water and milk sample with a pre-concentration factor of 200 for Hg(II) off-line analysis by cold vapor atomic absorption analysis. The pre-concentration factor attainable for quantitative recovery (>96%) of Hg(II) was 100 for a 1000 ml sample volume. Key words: Pre-concentration, Mercury(II), histidine functionalized multi-walled carbon nanotubes (MWCNTs-His).

Determination and preconcentration of Mercury(II) from natural water and milk sample by Modified nano polyacrylonitrile fiber

A simple method was developed for the preconcentration of Mercury(II) based on the adsorption of its Modified nano polyacrylonitrile fiber (PANF) complex. PANF was prepared by addition of acrylic fibers to ethanolamine (EA) with different concentration solutions. The stability of a chemically Modified nano polyacrylonitrile fiber were determined especially in concentrated hydrochloric acid which was then used as a recycling and preconcentration reagent for further uses of Modified nano polyacrylonitrile fiber. The application of this Modified nano polyacrylonitrile fiber for adsorption of a series of metal ions was performed by using different controlling factors such as the pH of metal ion solution and the equilibration shaking time by the static technique. Hg(II) was found to exhibit the highest affinity towards extraction by these Modified nano polyacrylonitrile fiber phases. The pronounced selectivity was also confirmed from the determined distribution coefficient (Kd) of all the metal ions, showing the highest value reported for Mercury(II) to occur by PANF. The potential applications of Modified nano polyacrylonitrile fiber for selective extraction of Mercury(II) to occur from aqueous solution were successfully accomplished as well as pre-concentration of low concentration of Hg(II) (40 pg ml-1) from natural tap water and milk sample with a pre-concentration factor of 200 for Hg(II) off-line analysis by cold vapor atomic absorption analysis. The preconcentration factor attainable for quantitative recovery (>96%) of Hg(II) was 100 for a 1000 mL sample volume. Key words: Preconcentration, Mercury(II), Modified nano polyacrylonitrile fiber.

Extraction of mercury (II) from sample water by Schiff base-chitosan grafted multi-walled carbon nanotubes

A functionalized Schiff base-chitosan-grafted multi-walled carbon nanotubes (S-CS-MWCNTs) material has been studied on pre-concentration and determination of trace mercury. In this process, the effects of solution pH solution, elution conditions on pre-concentration of trace mercury were studied and the effect of interfering ions was also investigated. A novel S-CS-MWCNTs solid-phase extraction adsorbent was synthesized by covalently grafting a Schiff base-chitosan (S-CS) onto the surfaces of oxidized MWCNTs. The stability of chemically modified S-CS-MWCNTs especially in concentrated hydrochloric acid was then used as a recycling and pre-concentration reagent for further uses of S-CS-MWCNTs. The application of S-CS-MWCNTs for sorption of a series of metal ions was performed by using different controlling factors such as the pH of metal ion solution and the equilibration shaking time by the static technique. Hg(II) was found to exhibit the highest affinity towards extraction by these S-CS-MWCNTs phases. The pronounced selectivity was also confirmed from the determined distribution coefficient or dissociation constant (Kd) of all the metal ions, showing the highest value reported for Hg(II) to occur by S-CS-MWCNTs. The potential applications of S-CS-MWCNTs for selective extraction of Hg(II) to occur from aqueous solution were successfully accomplished as well as pre-concentration of low concentration of Hg(II) (60 pg ml-1) from natural tap water with a pre-concentration factor of 100 for Hg(II) off-line analysis by cold vapor atomic absorption analysis. Key words: Pre-concentration, Hg(II), Schiff base-chitosan-grafted multiwalled carbon nanotubes (S-CS-MWCNTs).

Preconcentration of Ni(II) from sample water by modified poly (ethylene terephthalate)-grafted-acrylic acid/acryl amide fiber

Modified poly (ethylene terephthalate)-grafted-acrylic acid/acryl amide fiber was prepared by adding acrylic fibers to methanolamine (PET-AA/AAm) with different concentration solutions. The stability of a chemically modified PET-AA/AAm fiber especially in concentrated hydrochloric acid which was then used as a recycling and Preconcentration reagent for further uses of modified PET-AA/AAm fiber. The application of this modified PET-AA/AAm fiber for sorption of a series of metal ions was performed by using different controlling factors such as the pH of metal ion solution and the equilibration shaking time by the static technique. Ni(II) was found to exhibit the highest affinity towards extraction by these modified PET-AA/AAm fiber phases. The pronounced selectivity was also confirmed from the determined distribution coefficient (Kd) of all the metal ions, showing the highest value reported for Ni(II) to occur by modified PET-AA/AAm fiber. The potential applications of modified PET-AA/AAm fiber for selective extraction of Ni(II) to occur from aqueous solution were successfully accomplished as well as Preconcentration of low concentration of Ni(II) (60 pg ml-1) from natural tap water with a Preconcentration factor of 100 for Ni(II) off-line analysis by flame atomic absorption analysis. Key words: Preconcentration, Ni(II), modified poly (ethylene terephthalate)-grafted-acrylic acid/acryl amide fiber (PET-AA/AAm).

Preconcentration of Zn(II) from Sample Water by Phenyl-iminodiacetic Acid Grafted Multiwalled Carbon Nanotubes

: phenyl-iminodiacetic acid grafted multiwalled carbon nanotubes were prepared by grafted phenyl-iminodiacetic acid groups onto multi-walled carbon nanotubes via a diazotation reaction. The stability of chemically phenyl-iminodiacetic acid grafted multiwalled carbon nanotubes in concentrated hydrochloric acid which was then used as a recycling and pre-concentration reagent for further uses of phenyl-iminodiacetic acid grafted multiwalled carbon nanotubes. The application of this phenyl-iminodiacetic acid grafted multiwalled carbon nanotubes for sorption of a series of metal ions was performed by using different controlling factors such as the pH of metal ion solution and the equilibration shaking time by the static technique. Zn(II) was found to exhibit the highest affinity towards extraction by these phenyl-iminodiacetic acid grafted multiwalled carbon nanotubes phases. The pronounced selectivity was also confirmed from the determined distribution coefficient ( K d ) of all the metal ions, showing the highest value reported for Zn(II) to occur by phenyl-iminodiacetic acid grafted multiwalled carbon nanotubes. The potential applications of phenyl-iminodiacetic acid grafted multiwalled carbon nanotubes for selective extraction of Zn(II) to occur from aqueous solution were successfully accomplished as well as pre- concentration of low concentration of Zn(II) (60 pg ml -1 ) from natural tap water with a pre-concentration factor of 100 for Zn(II) off-line analysis by flame atomic absorption analysis.