Development of a four-zone carousel process packed with metal ion-imprinted polymer for continuous separation of copper ions from manganese ions,cobalt ions,and the constituent metal ions of the buffer solution used as eluent

A three-zone carousel process, in which Cu(II)-imprinted polymer (Cu-MIP) and a buffer solution were employed as adsorbent and eluent respectively, has been developed previously for continuous separation of Cu²⁺ (product) from Mn²⁺ and Co²⁺ (impurities). Although this process was reported to be successful in the aforementioned separation task, the way of using a buffer solution as eluent made it inevitable that the product stream included the buffer-related metal ions (i.e., the constituent metal ions of the buffer solution) as well as copper ions. For a more perfect recovery of copper ions, it would be necessary to improve the previous carousel process such that it can remove the buffer-related metal ions from copper ions while maintaining the previous function of separating copper ions from the other 2 impure heavy-metal ions. This improvement was made in this study by proposing a four-zone carousel process based on the following strategy: (1) the addition of one more zone for performing the two-step re-equilibration tasks and (2) the use of water as the eluent of the washing step in the separation zone. The operating conditions of such a proposed process were determined on the basis of the data from a series of single-column experiments. Under the determined operating conditions, 3 runs of carousel experiments were carried out. The results of these experiments revealed that the feed-loading time was a key parameter affecting the performance of the proposed process. Consequently, the continuous separation of copper ions from both the impure heavy-metal ions and the buffer-related metal ions could be achieved with a purity of 91.9% and a yield of 92.8% by using the proposed carousel process based on a properly chosen feed-loading time.     

Coordination numbers of hydrated divalent transition metal ions investigated with IRPD spectroscopy

Hydration of the divalent transition metal ions, Mn, Fe, Co, Ni, Cu, and Zn, with 5-8 water molecules attached was investigated using infrared photodissociation spectroscopy and photodissociation kinetics. At 215 K, spectral intensities in both the bonded-OH and free-OH stretch regions indicate that the average coordination number (CN) of Mn(2+), Fe(2+), Co(2+), and Ni(2+) is ~6, and these CN values are greater than those of Cu(2+) and Zn(2+). Ni has the highest CN, with no evidence for any population of structures with a water molecule in a second solvation shell for the hexa-hydrate at temperatures up to 331 K. Mn(2+), Fe(2+), and Co(2+) have similar CN at low temperature, but spectra of Mn(2+)(H(2)O)(6) indicate a second population of structures with a water molecule in a second solvent shell, i.e., a CN < 6, that increases in abundance at higher temperature (305 K). The propensity for these ions to undergo charge separation reactions at small cluster size roughly correlates with the ordering of the hydrolysis constants of these ions in aqueous solution and is consistent with the ordering of average CN values established from the infrared spectra of these ions.     

Application of xylenol orange to the separation of metal ions on amberlyst A-26 macroreticular anion-exchange resin

The possibility of using a sulphonated aromatic organic complexing agent-Xylenol Orange-for separation of metal ions on the macroreticular anion-exchanger Amberlyst A-26 has been investigated. The dependence of retention on pH was determined by the batch method for Al(3+), Cr(3+), Mn(3+), Fe(3+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Ga(3+), Rh(3+) Cd(2+), In(3+), Ir(3+), and Pb(2+). The selectivity differences make possible the separation of some of these metal ions. The following mixtures, of practical importance, have been separated: Al(3+)-In(3+), Ga(3+)-In(3+) Zn(2+)-In(3+), Cu(2+)-Mn(2+), in various ratios. The method has been applied to analysis of Ga-In alloy.     

Ultrasensitive CE for heavy metal ions using the variations in the chemical structures formed from new octadentate fluorescent probes and cationic polymers

Novel fluorescent probes have been developed for the ultratrace detection of heavy metal ions by capillary electrophoresis using laser-induced fluorescence detection. Based on a molecular design, the probes are composed of an octadentate chelating moiety, a macrocyclic DOTA (tetraazacyclododecanetetraacetic acid) and an acyclic DTPA (diethylenetriaminepentaacetic acid) frame, a spacer and a fluorophore (fluorescein). These were chosen on the basis of their ability to form kinetically inert and highly emissive complexes, and to prevent a quenching effect even with heavy and paramagnetic metal ions. Addition of a cationic polymer, polybrene, in the separation buffer provided high resolution and simultaneous detection of Ca(2+), Mg(2+), Cu(2+), Zn(2+), Ni(2+), Co(2+), Mn(2+), Cd(2+) and Pb(2+). The direct fluorescence detection of these metal ions with high sensitivity at lower ppt levels, typically 2-7 × 10(-11) M (potentially sub-ppt), was successfully achieved. While separation of anionic compounds using a counter cation ("Ion Association (IA)" mode) is typically controlled by the ion association equilibrium constants, K(ass), it was found that differences in the mobilities, μ(ep(IAC)), of the ion association complexes formed between the probe complexes and counter cations are the driving forces for separation in this new method. This suggests that each of the polybrene-probe complexes has different chemical structures among metal ions, which were able to be determined by CD spectra in this investigation. This novel separation mode was termed the "Ion Association Complex (IAC)" mode, distinct from the IA mode.     

Capillary isotachophoretic determinations of metal ions by use of complexation equilibria in acetone-water medium

The determination of metal ions by capillary isotachophoresis and the complexation equilibria between metal ions and polyaminopolycarboxylic acids has been investigated. A seven-component mixture of metal ions can be separated in 45% v/v acetone-water medium when EDTA or DCTA is used as the terminating ion. Linear calibration graphs are obtained for a standard mixture of Mn(+), Cu(2+), Zn(2+), Cd(2+), Pb(2+) and Fe(3+) in the range 0.5-5.0 nmole, with relative standard deviations of 1.0% or better. The effective mobilities of the Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes increase in parallel with the stability constants, except for the Cu(II) complexes. It is concluded that the abnormal behaviour of the Cu(II) complexes may be attributed to a difference in steric configuration.     

High-voltage contactless conductivity detection of metal ions in capillary electrophoresis

The detection of alkali, alkaline earth and heavy metal ions with a high-voltage capacitively coupled contactless conductivity detector (HV-C(4)D) was investigated. Eight alkali, alkaline earth metal ions and ammonium could be separated in less than 4 min with detection limits in the order of 5 x 10(-8) M. The heavy metals Mn2+, Pb2+, Cd2+ Fe2+, Zn2+, Co2+, Cu2+ and Ni2+ could also be successfully resolved with a 10 mM 2-(N-morpholino)ethanesulfonic acid/DL-histidine (MES/His)-buffer. Zn2+, Co2+, Cu2+ and Ni2+ showed an indirect response. The detection limits for the heavy metals were determined to range from about 1 to 5 microM.     

Adsorption of some bivalent heavy metal ions from aqueous solutions by manganese nodule leached residues

The leached residue, generated after selective extraction of Cu, Ni, and Co in sulfur dioxide-ammonia leaching of manganese nodules, was characterized and batch isothermal adsorption experiments were conducted at ambient temperature to evaluate the effectiveness of the water-washed leached residue for removal of different bivalent metal ions from aqueous synthetic solutions. The effects of pH, initial metal ion concentrations, amount of adsorbent, interfering ions, and heat treatment were also investigated. The uptake of metal ions increased with increasing pH. Under identical conditions the adsorption capacity increased in the order Cd(2+)相似文献   

Solid phase extraction and determination of metal ions in aqueous samples using Quercetin modified Amberlite XAD-16 chelating polymer as metal extractant

A new chelating polymer has been developed using Amberlite XAD-16 anchored with Quercetin. The modified polymer was characterised by Fourier Transform Infra Red (FTIR) spectroscopy, thermogravimetric analysis, surface area analysis and elemental analysis. The Quercetin anchored polymer showed superior binding affinity for Cr(III), Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) with greater than 95% adsorption under optimum conditions. The optimum pH conditions for the quantitative sorption of metal ions were studied. The developed method showed superior extraction qualities with high metal loading capacities of 387, 313, 195, 473, 210 and 320 µmol g^?1 for Cu(II), Co(II), Cr(III), Fe(III), Mn(II) and Ni(II), respectively. The rate of metal ion uptake i.e. kinetics studies performed under optimum levels, showed t _1/2 for Co(II), Cu(II), Cr(III), Fe(III), Mn(II) and Ni(II) is 20, 15, 25, 10, 30 and 15 min, respectively. Desorption of metal ions was effective with 10 mL of 2 M HCl prior to analysis using flame atomic absorption spectrophotometer. The chelating polymer was highly ion selective in nature even in the presence of interferent ions, with a high preconcentrating ability for the metal ions of interest. The developed chelating polymer was tested on its utility with synthetic and real samples like river, tap water samples and also with multivitamin tablets. It showed relative standard deviation (R.S.D.) values of/less than 3.0% reflecting on the accuracy and reproducibility of data using the newly developed chelating polymer.     

Investigations on the effect of aqueous acetone medium on separation of metal ions on Chelex 100 ion-exchanger

The use of glycine as a complexing agent in acetone-water medium for the separation of metal ions with Chelex 100 chelating resin has been investigated. The affinity of metal ions for Chelex 100 in the presence of glycine in acetone-water and aqueous medium was determined as a function of acidity and it was established that the presence of acetone is an essential factor in production of differentiation in the selectivity and for consequent separation of a number of mixtures of metal ions [Cu(II)Co(II); Cu(II)Al(III)Pb(II); Cu(II)Ni(II)Co(II); Cu(II)Ni(II)Pb(II)]. The mechanism of the effect of acetone is discussed.     

Investigation on C2-ceramide complexes with transition metal ions using electrospray ionization tandem mass spectrometry

Electrospray ionization-tandem mass spectrometry (ESI-MS/MS) is applied for the investigation of C(2)-ceramide complexes with transition metal ions. Ceramide plays an important role in the regulation of various signaling pathways leading to proliferation, differentiation or apoptotic cell death. The formation and fragmentation of doubly charged cluster ions as well as singly charged cluster ions of C(2)-ceramide with transition metal ions (Mn(2+), Fe(2+), Co(2+) and Ni(2+)) are studied by ESI-MS/MS in the positive mode. Tube lens offset voltage and concentrations of C(2)-ceramide and transition metals are optimized to determine the best conditions for generating doubly charged cluster ions. The fragmentation pathways of metal ion complexes with C(2)-ceramide and the compositions of these complexes are determined by collision induced dissociation (CID). All transition metal ions (Mn(2+), Fe(2+), Co(2+) and Ni(2+) except Cu(2+)) shows similar complexation with C(2) ceramide. The unique complexation behavior of copper(II) is responsible for the different geometry of the complexes and relatively lower affinity of ceramide to copper(II) than those to other transition metals.     

Solid-phase extraction for the decontamination of alkali metal, alkaline Earth metal, and ammonium salts from heavy metal ions

Salicylaldoxime-immobilized silica gel was characterized and used as a potential sorbent for heavy metal ions, viz. Cu(II), Ni(II), Co(II), and Zn(II). The experimental conditions were optimized both in batch and column processes to achieve the maximum efficiency. Kinetic and thermodynamic parameters as well as isotherm constants were evaluated to test the feasibility of the process. The role of various metal ions and different anions were tested in order to monitor the process in case of real samples. The alkali metal, alkaline earth metal, and ammonium salts do not have any effect on the said process. This differential behavior can be effectively used for the decontamination of alkali metal, alkaline earth metal, and ammonium salts from Cu(II), Ni(II), Co(II), and Zn(II) ions via solid phase extraction following AAS measurement. The purification of the salts was confirmed by voltammetric experiment.     

Determination of heavy metal ions by microchip capillary electrophoresis coupled with contactless conductivity detection

An integrated detection circuitry based on a lock-in amplifier was designed for contactless conductivity determination of heavy metals. Combined with a simple-structure electrophoresis microchip, the detection system is successfully utilized for the separation and determination of various heavy metals. The influences of the running buffer and detection conditions on the response of the detector have been investigated. Six millimole 2-morpholinoethanesulfonic acid + histidine were selected as buffer for its stable baseline and high sensitivity. The best signals were recorded with a frequency of 38 kHz and 20 V(pp). The results showed that Mn(2+), Cd(2+), Co(2+), and Cu(2+) can be successfully separated and detected within 100 s by our system. The detection limits for five heavy metals (Mn(2+), Pb(2+), Cd(2+), Co(2+), and Cu(2+)) were determined to range from about 0.7 to 5.4 μM. This microchip system performs a crucial step toward the realization of a simple, inexpensive, and portable analytical device for metal analysis.     

Separation of cephalosporins on thin silica gel layers impregnated with transition metal ions and by reversed-phase TLC

Cephalosporin antibiotics were separated on thin layer plates impregnated with transition metal ions, Mn(2+), Fe(2+), Co(2+), Ni(2+) and Cu(2+), using different concentrations. Various solvent systems were developed for the study and were used for separation of these analytes. Impregnation was observed to have an effect on hR(F) values, removed tailing of analytes and improved the resolution. The results have been discussed for each metal ion and compared, and the best conditions of separation have been identified. Activation time of thin layer plates impregnated with 0.1% FeSO(4) was found to affect both hR(F) values and resolution of cephalosporins. New solvent systems are reported for both normal phase and reversed-phase TLC.     

Microchip separations of transition metal ions via LED absorbance detection of their PAR complexes

Micellar electrokinetic chromatography was utilized in the electrophoretic separation of seven transition metal ions, colorimetrically complexed by 4-(2-pyridylazo)resorcinol (PAR) on a glass capillary electrophoresis microchip. Detection of the PAR metal chelates was demonstrated using a green light emitting diode (540 nm) and a miniature photomultiplier tube. Parameters investigated included the effect of buffer type, pH and surfactant concentration (sodium dodecyl sulfate, SDS) on the separation efficiency. The optimally determined background electrolyte contained 10 mM ammonium phosphate buffer (pH 7.5), 1 mM PAR to prevent kinetic lability problems and 75 mM SDS for enhanced resolution. The separation of seven transition metal ions, Co2+, V3+, Ni2+, Cu2+, Fe2+, Mn2+ and Cd2+, was achievable in under 65 s, with the resolution of each metal ion in excess of 1.60. Detection limits obtained ranged from 400 ppb for Ni2+ to 1.2 ppm for Mn2+.     

Spectrophotometric and conductometric study of complexation of salophen and some transition metal ions in nonaqueous polar solvents

The complexation reaction between Cu(2+), Co(2+) and Ni(2+) metal cations with N,N'-bis(salicylidene)-1,2-phenylenediamine (salophen), in three nonaqueous polar solvents such as: acetonitrile (AN), dimethyl sulfoxide (DMSO), methanol (MeOH) and two binary mixtures of AN:DMSO and AN:MeOH at 25 degrees C were studied by spectrophotometric and conductometric methods. All investigated metal ions form 1:1 ML complex which their stability constants were determined and increase as Irving-Williams stability order of Co(2+)相似文献   

Study of metal ion labeling of the conformational and charge states of lysozyme by ion mobility mass spectrometry

The efficiency of Zn(2+), Cu(2+), Ni(2+), Co(2+), Fe(2+) or Mn(2+) labeling of the conformational and charge states of lysozyme was studied in H(2)O solvent at pH 2.5-6.8. Labeling of lysozyme was conducted with 50 M, 100 M and 500 M excess of the metal ion, resulting in the number of metal ions attached to lysozyme increasing two-fold over this range. At pH 6.2-6.8, Zn(2+), Cu(2+), Ni(2+), Co(2+) and Mn(2+) labeled the highly folded 7+ conformer and the 8+ and 9+ partially unfolded conformers of lysozyme with the same number of metal ion tags, with only Fe(2+) exhibiting no labeling. Lysozyme conserved its charge after metal ion labeling which shows at each charge state the divalent metal ion is replacing two protons. As the pH is lowered to 4.7-5.0 and 2.5-2.9, the labeling of lysozyme by Zn(2+), Cu(2+), Ni(2+), Co(2+) or Mn(2+) decreased in efficiency due to increased competition from protons for the aspartate and glutamate binding sites. The metal ions preferentially labeled the highly folded 7+ and partially unfolded 8+ conformers, but labeling decreased as the charge of lysozyme increased. In contrast to the other metal ions, Fe(2+) exhibited labeling of lysozyme only at the lowest pH of 2.8. At higher pH, the oxidation of Fe(2+) and formation of hydroxy-bridged complexes probably make the Fe(2+) unreactive towards lysozyme.     

Sorption and permeation behaviour of metal thiocyanate complexes on cellulose acetate polymers

Various metal thiocyanate complexes in aqueous solution were sorbed on solid cellulose acetate polymers. The sorption selectivity increased in the order Zn(2+) > Fe(3+) > Cu(2+) > Co(2+) > Ni(2+). The sorption behaviour followed a Langmuir-type adsorption isotherm, and the maximum adsorption capacity was 6.1 x 10(-5) mole of complex per g of polymer under optimum conditions. The zinc species sorbed appear to be NH(4)Zn(H(2)O)(SCN)(3) or (NH(4))(2)Zn(SCN)(4) according to analysis of the sorption equilibrium. The ion-association species formed by the complex zinc anion and the ammonium ion was supposed to be sorbed (or "extracted") onto the polymer matrix. As an application of sorption of metal complexes, a new hyperfiltration process was proposed for selective separation of metal ions. Thus, a mixture of metal thiocyanate complexes was hyperfiltered through cellulose acetate membranes. Permeation of certain metal complexes was preferred, and the selectivity was found to be similar to the sorption selectivity. These findings lead to a generalized idea that hyperfiltration separation of ionic species, particularly anionic metal complexes, can be attained by using polymer membranes which selectively adsorb or extract such ionic species as ion-association complexes onto the polymer matrix.     

Metal Complexes of Pharmacophore-Containing Pectin with d -Elements Ions (Cu 2+ , Co 2+ , and Mn 2+ )

Spectral methods have been used to study the complexation of apple pectin modified with organic pharmacophores (nicotinic, salicylic, 5-aminosalicylic, or anthranilic acid) with Cu2+, Co2+, and Mn2+ ions in an aqueous solution. The composition and stability series of the metal complexes, corresponding to the empirical Irving–Williams series, have been established. The standard thermodynamic parameters (ΔH°, ΔG°, and ΔS°) of the complexation process have been calculated. It has been shown by means of 13C NMR and IR spectroscopy that the interaction of pharmacophore-containing pectins with d-metal ions (Cu2+, Co2+, Mn2+) occurs via the carbonyl and hydroxyl groups of the modified polymer matrices. The viscosity and thermal properties of the metal complexes have been determined.     

Capillary electrophoresis as a nanoreactor of separation capability: on-capillary reaction catalyzed by transition metal ions

The catalytic oxidation of 1,2-dihydroxy-benzene-3,6-disulfonate (tiron) by metal ions has been studied for detection of the metal ions in capillary electrophoresis (CE). Although Co(2+) shows the strongest catalytic capability, some other metal ions also catalyze this reaction. If metal ions encounter a H(2)O(2 )zone after electrophoretic separation in the running buffer containing tiron, tiron is catalytically oxidized while the metal ion passes through the H(2)O(2) zone. Anionic tiron radicals produced by the reaction are finally measured by the detector; in this scheme, the capillary acts as a nano- or microreactor as well as a microseparator. The effective capillary length can be controlled by changing the interval between metal ion and H(2)O(2) injections. This scheme has been successfully applied to the detection of Co(2+), Cu(2+), Mn(2+), and VO(2+). The detectability is discussed from several viewpoints, such as the intrinsic catalyst ability of metal ions, the kinetics of the catalytic reaction, and reaction times determined by the mobility of the zone of the metal ion. Some strange behaviors, which cannot be predicted by batch experiments, are also reported.     

Catalysis of hydrolysis and aminolysis of non-classical beta-lactam antibiotics by metal ions and metal chelates.

The Zn(2+)-tris (hydroxymethyl)aminomethane (Tris) system has a great catalytic effect on the hydrolysis and aminolysis of some beta-lactam antibiotics. In order to ascertain the mechanism of this catalysis we have analysed the effects of the beta-lactam antibiotic structure. First we studied the kinetics of the decomposition of imipenem, SCH 29482, aztreonam and nocardicin A in aqueous solution of Tris at 35.0 degrees C, 0.5 mol.dm-3 ionic strength and in the presence of metal ions (Zn2+, Cd2+, Co2+, Cu2+, Ni2+ and Mn2+). From these studies, we conclude that Tris and metal ions (in separate solutions) exert a great catalytic effect on the hydrolysis of imipenem and SCH 29482. We suggest that in metal ion solutions a 1:1 complex is formed between the metal ion and beta-lactam antibiotic, which is attacked by hydroxide ions. Studies of the degradation of the antibiotics studied in solutions of Tris and metal ions together indicate that the systems Cd(2+)-Tris and Zn(2+)-Tris have a great catalytic effect on the hydrolysis and aminolysis of imipenem and SCH 29482. We suggest that this catalysis takes place via a ternary complex in which the metal ion plays a double role by (a) placing the antibiotic and the Tris in the right position for the reaction and (b) lowering the pKa of the hydroxide group of Tris, which is coordinated with the metal ion, generating a strong nucleophile.