Separation of gallium and indium from ores matrix by sorption on Amberlite XAD-2 coated with PAN

A chelating sorbent obtained by adsorption of 1-(2-pyridylazo)-2-naphthol (PAN) on Amberlite XAD-2 was used for the preconcentration of Ga and In. The analytical characteristics of the chelating sorbent were investigated and optimun sorption conditions for these metals under dynamic conditions were established. A peristaltic pump is used to adjust the flow rate of the solution. Elements are collected from the column by using a mixture adjusted to a pH range of 4–7 and 6–12 by ammonia or ammonium chloride for Ga and In, respectively. The procedure developed was applied to the analysis of different ores. Received: 10 July 2000 / Revised: 21 September 2000 / Accepted: 23 September 2000     

Preparation and analytical characterization of a chelating resin coated with 1-(2-pyridylazo)-2-naphthol

A chelating sorbent was obtained by deposition of 1-(2-pyridylazo)-2-naphthol on Amberlite XAD-4. The analytical characteristics of the sorbent were established and optimum sorption conditions for Cu, Zn, Fe, Cd, Ni, and Pb under static and dynamic conditions were determined. The sorbent was applied to analysis of river water. After group separation of traces of metals on the sorbent and subsequent elution with hydrochloric add, the metals were determined in the effluent by atomic-absorption spectrophotometry.     

Efficiency and application of poly(acryldinitrophenylamidrazone-dinitroacrylphenylhydrazine) chelating fiber for pre-concentrating and separating trace Au(III), Ru(III), In(III), Bi(III), Zr(IV), V(V), Ga(III) and Ti(IV) from solution samples

Poly(acryldinitrophenylamidrazone-dinitroacrylphenylhydrazine) chelating fiber was synthesized from polyacrylonitrile fiber and used for enrichment and separation for traces of Au(III), Ru(III), In(III), Bi(III), Zr(IV), V(V), Ga(III) and Ti(IV) ions from solution samples. The acidity, rate, re-use, capacity and interference on the adsorption of ions on the chelating fiber as well as the conditions of desorption of these ions from the chelating fiber were investigated by means of inductively coupled plasma optical emission spectrometry. The results show that 10-100 ngml(-1) of Au(III), Ru(III), In(III), Bi(III), Zr(IV), V(V), Ga(III) and Ti(IV) ions can be quantitatively enriched by the chelating fiber at a 2 mlmin(-1) of flow rate in the range pH 4-5, and desorbed quantitatively with 20 ml of 5 M HCl for In(III), Bi(III), Zr(IV), V(V), Ga(III), Ti(IV) and 20 ml of 4 M HCl+2% CS(NH(2))(2) solution for Au(III), Ru(III) (with recovery>95%). 50- to 500- fold excesses of Fe(III), Al(III), Mg(II), Mn(II), Ca(II), Cu(II), Ni(II) ions cause little interference in the concentration and determination of analyzed ions. When the fiber was reused for 8 times, the recoveries of the above ions enriched by the fiber were still over 87%. The relative standard deviations (RSDs) for the enrichment and determination of 10 ngml(-1) Au, Ru, In, Bi, Ga and 1 ngml(-1) Zr, V, Ti were lower than 3.0%. The results obtained for these ions in real solution samples by this method were basically in agreement with the given values with average errors of less than 6.3%. FT-IR spectra show that existence of NNCNHNH, OCNHNH and NO(2) functional groups are verified in chelating fiber, and Au(III) or Ru(III) is mainly combined with nitrogen (or oxygen) of the groups to form a chelate complex.     

Novel surface molecularly imprinted material modified multi-walled carbon nanotubes as solid-phase extraction sorbent for selective extraction gallium ion from fly ash

A new gallium (Ga(III)) ion-imprinted multi-walled carbon nanotubes (CNTs) composite sorbent was synthesized by a surface imprinting technique. The Ga(III) ion-imprinted/multi-walled carbon nanotubes (Ga(III)-imprinted/CNTs) sorbent was characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), nitrogen adsorption experiment, static adsorption experiment, and solid-phase extraction (SPE) experiment. The effects of sample volume, sample pH, washing and elution conditions on the extraction of Ga(III) ion from real sample were studied in detail. The imprinted sorbent offered a fast kinetics for the adsorption of Ga(III). The maximum static adsorption capacity of the imprinted sorbent towards was 58.8 μmol g⁻¹. The largest selectivity coefficient for Ga(III) in the presence of Al(III) was over 57.3. Compared with non-imprinted sorbent, the imprinted sorbent showed good imprinting effect for Ga(III) ion, the imprinting factor (α) was 2.6, the selectivity factor (β) was 2.4 and 2.9 for Al(III) and Zn(II), respectively. The developed imprinted SPE method was applied successfully to the detection of trace Ga(III) ion in fly ash samples with satisfactory results.     

荧光试剂SPAEC的合成及分析化学特性研究

合成了新荧光试剂2-(5'-磺基-2'-苯酚-1'-偶氮)-5-乙氨基-4-甲酚(SPAEC)。用等色点光度法测得试剂的离解常数为pK1=3.42, pK2=5.46, pK3=7.99。考察了SPAEC与金属离子的螯合显色和荧光反应; 建立了测定镓、铝的反应条件, 在PH3.8-5.4或PH4.0-5.5的乙酸缓冲介质中均形成:1型具荧光活性的有色螯合物, 可相应测定15-150ppb镓及1.5-30ppb铝, 试用于半导体及合金分析。研究了Kalman滤波荧光光度法, 实现了镓与铝的同时测定, 所适应的浓度比例范围为40:1(0)-1(0):14。     

Synthesis and analytical characterization of a chelating resin loaded with dithizone

A chelating sorbent loaded with dithizone was obtained by chemical reaction with styrene-DVB (5%) copolymer as matrix. The analytical characteristics of the sorbent were established and optimum sorption conditions for Ag, Cu, Cd, Pb, Ni, Co and Zn under static and dynamic conditions determined. The sorbent was applied to determination of copper and lead in river water and of silver in electrolytic copper. After separation of traces of metals on the sorbent and desorption with hydrochloric acid, the metals were determined in the effluent by atomic-absorption spectrophotometry.     

Determination of antimony(III,V) in natural waters by separation and preconcentration on a thionalide loaded resin followed by neutron activation analysis

A chelating sorbent obtained by immobilization of thionalide on the macroporous resin Bio Beads SM-7 was used for speciation of antimony(III) and (V) in natural waters. Antimony(III) was separated from Sb(V) by sorption on a column with the sorbent at pH 5. Antimony(V) in the effluent was reduced to Sb(III) and preconcentrated by sorption on the sorbent from 0.5M HCl solution. Both the separated species were determined directly on the sorbent by neutron activation analysis.     

New alpha-amino phenylalanine tetrazole ligand for immobilized metal affinity chromatography of proteins

A new chelating compound has been developed for use in the immobilized metal affinity chromatographic (IMAC) separation of proteins. The bidentate ligand, alpha-amino phenylalanine tetrazole, 4, was synthesized via a five-step synthesis from N-fluorenylmethoxycarbonyl phenylalanine and then immobilized onto silica through the epoxide coupling procedure. The binding behavior of the resulting IMAC sorbent, following chelation with Zn2+ to a density of 183 micromol Zn2+ ions/g silica, was characterized by the retention of proteins in the pH range of 5.0-8.0, and by the adsorption behavior of lysozyme with frontal chromatography at pH 6.0 and 8.0. The prepared column showed the separation ability to four test proteins and the retention time of these proteins increased with an increase in pH. From the derived isotherms, the adsorption capacity, qm, for the binding of lysozyme to immobilized Zn2+-alpha-amino phenylalanine tetrazole-silica was found to be 1.21 micromol/g at pH 6.0 and 1.20 micromol/g sorbent at pH 8.0, respectively, whilst the dissociation constants KD at these pH values were 5.22x10(-6) and 3.49x10(-6) M, respectively, indicating that the lysozyme was retained more stable under alkaline conditions, although the binding capacity in terms of micromole protein per gram sorbent remained essentially unchanged.     

Properties and Application of a Chelating Sorbent Prepared by Modification of LiChroprep-NH<Subscript>2</Subscript> with Calcon

A new chelating sorbent for metal ions was prepared by modification of chemically modified silica – LiChroprep-NH₂ with Calcon. The molecular mechanism of binding this reagent to the surface of the applied carrier is presented. The properties of this sorbent were compared to analogous sorbents with a plain silica carrier and chemically modified silicas – LiChroprep-RP containing Calcon. The advantages of the new sorbent compared to the silica and LiChroprep-RP chelating sorbents are demonstrated. The sorbent obtained was applied as stationary phase in solid-phase extraction (SPE) for separations of some chosen mixtures of metal ions and for additional purification of aqueous solutions of salts of alkali metals from trace amounts of heavy metals. The multiple use of the sorbent based on LiChroprep-NH₂ in sorption-desorption processes of metal ions without deterioration of its sorption capacity is demonstrated.     

New ligand, N-(2-pyridylmethyl)aminoacetate, for use in the immobilised metal ion affinity chromatographic separation of proteins.

A new chelating compound has been developed for use in the immobilised metal ion affinity chromatographic separation of proteins. The tridentate ligand, sodium N-(2-pyridylmethyl)aminoacetate (carbpyr), 1, was prepared via a one-step synthesis from 2-picolylamine, 3 and then immobilised onto Sepharose CL-4B through the epoxide coupling procedure. The binding behaviour of the resulting IMAC sorbent, following chelation with Cu2+ ions to a density of 152 micromol Cu2+ ions/g gel was characterised by frontal analysis experiments using horse heart myoglobin (HMYO) at pH 7.0 and pH 9.0. From the derived isotherms, the adsorption capacity, q(m), for the binding of HMYO to immobilised Cu2+-N-(2-pyridylmethyl)aminoacetate (im-Cu2+-carbpyr)-Sepharose CL-4B at these pH values was found to be 1.92 and 1.91 micromol/g sorbent, respectively, whilst the dissociation constants K(D) were 0.0092 x 10(-6) M and 0.0062 x 10(-6) M at pH 7.0 and pH 9.0, respectively, indicating that the HMYO-im-Cu2+-N-(2-pyridylmethyl)aminoacetate complex was more stable under alkaline conditions, although the binding capacity in terms of micromol protein/g gel remained essentially unchanged. The selectivity features of the im-Cu2+-carbpyr-Sepharose CL-4B sorbent were further characterised in terms of the binding properties with several human serum proteins at pH 5.0, pH 7.0 and pH 9.0.     

Synthesis and Applications of Poly(Acrylphenylamidrazone-Phenyl-Hydrazide-Acylphenylhydrazine) Chelating Fiber for Preconcentration and Separation of Trae In(III), Zr(IV), Tl(I), V(V), Ga(III) and Ti(IV) from Solution Samples

 An ICP-OES method using a new poly (acrylphenylamidrazone-phenylhydrazide-acylphenylhydrazine) chelating fiber to preconcentrate and separate trace In(III), Zr(IV), Tl(I), V(V), Ga(III) and Ti(IV) ions from solution samples has been established. The new chelating fiber was synthesized using polyacrylonitrile fiber as a starting material and the structure of the chelating fiber was determined by FT infrared spectrometry. The acidity, adsorption rate, re-use, capacity and interference on the adsorption of ions on the chelating fiber as well as the conditions of desorption of these ions from the chelating fiber were investigated by means of inductively coupled plasma optical emission spectrometry (ICP-OES). The results show that the relative standard deviations for the determination of 10 ng/ml In, Tl, Ga and 1 ng/ml Zr, V, Ti were lower than 2.5%. The results obtained for these ions in real solution samples by this method were basically in agreement with the given values with average errors of less than 4%. Received November 29, 2000. Revision May 22, 2001.     

A new bis(3-hydroxy-4-pyridinone)-IDA derivative as a potential therapeutic chelating agent. Synthesis, metal-complexation and biological assays

A new bis(3-hydroxy-4-pyridinone) derivative of iminodiacetic acid, imino-bis(acetyl(1-(3'-aminopropyl)-3-hydroxy-2-methyl-4-pyridinone)), IDAPr(3,4-HP)(2), has been prepared and studied in its interaction with a set of hard metal ions. This tetradentate ligand presents a much higher chelating efficiency for trivalent hard metal ions (Fe, Ga, Al) than the monodentate derivative Deferriprone, namely at the diluted conditions prevailing in physiological conditions and at low clinical doses. A similar behaviour was also observed for the complexation with Zn(II) but at a significantly lower extent. This compound presents a moderate hydrophilic character at physiological pH (logD=-1.72). In vivo assays showed much more rapid clearance of (67)Ga from most tissues of metal-loaded mice than the drug Deferriprone and the radioactivity excretion occurs mostly through the kidneys. Therefore, results from in vitro and in vivo studies indicated good perspectives for this compound to be a potential decorporating agent for hard metal ions in overload situations without depletion of essential metal ions such as zinc.     

Efficiency of a new poly(acrylamidrazone-hydrazide lacmoid) chelating fibre for preconcentrating and separating traces of chromium, gallium, indium and titanium from solutions

A new poly(acrylamidrazone-hydrazide lacmoid) chelating fibre has been synthesized from polyacrylonitrile fibre and used for the preconcentration and separation of traces of Cr(III), Ga(III), In(III) and Ti(IV) from solutions with satisfactory results. These ions can quantitatively be enriched by the chelating fibre at a flowrate of 6 ml/min at pH 6, and quantitatively desorbed with 10 ml of eluent at a rate of 4 ml/min. The chelating fibre reused ten times can still quantitatively concentrate traces of the above ions; twenty to two hundred-fold excesses of coexistent ions caused only little interference. With concentrations of 10 ng/ml Cr(III) and Ti(IV), and 50 ng/ml Ga(III) and In(III), the RSD was in the range of 1.4–4.6%. The contents determined in real samples were generally in agreement with the results obtained by HG-AAS; the recoveries of added standards were >96%.     

Evaluation of sorption and desorption characteristics of cadmium, lead and zinc on Amberlite IRC-718 iminodiacetate chelating ion exchanger

A chelating type ion exchange resin (Amberlite IRC-718), containing iminodiacetate groups as active sites, has been characterized regarding the sorption and subsequent elution of Cd, Zn and Pb, aiming to metal preconcentration from solution samples of different origins. The methodology developed is based on off-line operation employing mini columns made of the sorbent. The eluted metals were determined by flame atomic absorption spectrometry. The effect of column conditioning, influent pH and flow rate during the sorption step, and the nature of the acid medium employed for desorption of the retained metals were investigated. Working (breakthrough) and total capacities were measured under dynamic operating conditions and the results compared with those obtained with Chelex-100, a resin extensively employed for analytical preconcentration. Structural information on the complexation of metals by the chelating groups was obtained by Fourier Transform infrared spectrometry. The analytical response of the Amberlite sorbent was assessed for the analysis of water samples and digestates of marine sediments.     

Synthesis and efficiency of a spherical macroporous epoxy-melamine chelating resin for preconcentrating trace elements from solutions

A new spherical macroporous epoxy-melamine chelating resin was synthesized simply and rapidly and used for the preconcentrating and separation of trace of Ga(III), In(III),Bi(III), Sn(IV)and Ti(IV) ions from sample solutions. The ions analyzed can be quantitatively enriched by the resin at a flow-rate of 2ml/min at pH4,and quantitatively desorbed with 10ml of 2mol/L HCl+0.2gCS(NH₂)₂ at a flow-rate of 1ml/min with recoveries of over 97%,The chelating resin can be reused 7times without obvious loss of efficiency.     

Verbrückende und terminale Koordination von Ga–Ga-Bindungen durch die Chelatliganden Imidotetraphenyldiphosphinat bzw. -dithiodiphosphinat

Bridging and Terminal Coordination of Ga–Ga Bonds by the Chelating Ligands Imidotetraphenyldiphosphinate and -dithiodiphosphinate Tetrakis[bis(trimethylsilyl)methyl]digallane(4) ( 1 ) reacted with imidotetraphenyldiphosphinic acid to yield two products, which were separated by recrystallization: The first one, bis[bis(trimethylsilyl)methyl]-imidotetraphenyldiphosphinato-O,O′-gallium ( 2 ), resulted from the cleavage of the Ga–Ga bond and contained a dialkylgallium unit, which was coordinated by a chelating imidodiphosphinato ligand. The digallium compound 1,2-bis[bis(trimethylsilyl)methyl]-bis(μ-tetraphenyldiphosphinato-O,O′)digallium ( 3 ) was formed as the second product by a substituent exchange reaction and the release of bis(trimethylsilyl)methane. Its Ga–Ga bond (245.7 pm) was bridged by two imidodiphosphinato ligands. In contrast, the reaction of digallane(4) 1 with the sulfur derivative imidotetraphenyldithiodiphosphinic acid afforded a complicated mixture of unknown products. A compound analogous to 3 containing two imidodithiodiphosphinato ligands ( 5 ) was, however, obtained in a moderate yield by the precipitation of lithium acetate, when we treated dialkyldi(μ-acetato)digallium ( 4 ) with lithium imidotetraphenyldithiodiphosphinate. Remarkably, the chelating ligands did not adopt a bridging position across the Ga–Ga bond (249.9 pm) similar to 3 , but each one was terminally coordinated to one Ga atom.     

Synthesis, characterisation and evaluation of polydithiocarbamate resin supported on macroreticular styrene-divinylbenzene copolymer for the removal of trace and heavy metal ions

A new chelating resin was synthesised by the modification of styrene-divinylbenzene (2%) copolymer and incorporation of dithiocarbamate groups. The polydithiocarbamate resin was characterised by elemental analysis, thermal studies and IR studies. The analytical characteristics of the sorbent were established and optimum sorption conditions for Cu, Ni, Pb, Fe, As and Mn determined. The total sorption capacity of the resin was 37 mg g⁻¹ for Ni(II), 35 mg g⁻¹ for Cu(II), 29 mg g⁻¹ for Fe(III) and 23 mg g⁻¹ for Pb(II). The optimum pH for the removal of metal ions was 3-5 for Ni(II), 5 for Cu(II), 4 for Fe(III) and 4-5 for Pb(II). High sorption capacity was observed when compared with other conventional chelating polymers. The sorption kinetics was fairly rapid, as apparent from the loading half time t_1/2 values, indicating a better accessibility of the chelating sites.     

A solid molecular basket sorbent for CO2 capture from gas streams with low CO2 concentration under ambient conditions

In this paper, a solid molecular basket sorbent, 50 wt% PEI/SBA-15, was studied for CO(2) capture from gas streams with low CO(2) concentration under ambient conditions. The sorbent was able to effectively and selectively capture CO(2) from a gas stream containing 1% CO(2) at 75 °C, with a breakthrough and saturation capacity of 63.1 and 66.7 mg g(-1), respectively, and a selectivity of 14 for CO(2)/CO and 185 for CO(2)/Ar. The sorption performance of the sorbent was influenced greatly by the operating temperature. The CO(2)-TPD study showed that the sorbent could be regenerated under mild conditions (50-110 °C) and was stable in the cyclic operations for at least 20 cycles. Furthermore, the possibility for CO(2) capture from air using the PEI/SBA-15 sorbent was studied by FTIR and proved by TPD. A capacity of 22.5 mg g(-1) was attained at 75 °C via a TPD method using a simulated air with 400 ppmv CO(2) in N(2).     

Calcon-modified silica gel sorbent. Application to preconcentration or elimination of trace metals

Silica gel impregnated with a mixture of Aliquat 336 and Calcon was used as chelating sorbent for preconcentration of metals from dilute aqueous solutions and their separation as well as for additional purification of analytical grade sodium and potassium salts from other metals. The relative capacities of sorbent towards 33 metal ions were determined in the pH range 1-9 as well as the concentrations of hydrochloric and perchloric acid eluting the retained metals. It was found that Calcon was not eluted from sorbent with 5M perchloric and 10M hydrochloric acids. The rate of sorption for Mg, Ca, Cu, Zn, Al, Cr(III) and Fe(III) was also studied and it was found that relatively high flow-rates (up to 5 ml/min) can be used for solutions passed through the column. The sorbent was used for preconcentration of traces of some metals from aqueous solutions before their determination by AAS, for separation of metal ion mixtures by column extraction chromatography and for additional purification of potassium chloride solutions used as supporting electrolyte in determination of some heavy metals by anodic stripping voltammetry.     

Simultaneous preconcentration of uranium(VI) and thorium(IV) from aqueous solutions using a chelating calix[4]arene anchored chloromethylated polystyrene solid phase

A new chelating polymeric sorbent is developed using Merrifield chloromethylated resin anchored with calix[4]arene-o-vanillinsemicarbazone for simultaneous separation and solid phase extractive preconcentration of U(VI) and Th(IV). The “upper-rim” functionalized calix[4]arene-o-vanillinsemicarbazone was covalently linked to Merrifield resin and characterized by FT-IR and elemental analysis. The synthesized chelating polymeric sorbent shows superior binding affinity towards U(VI) and Th(IV) under selective pH conditions. Various physico-chemical parameters that influence the quantitative extraction of metal ions were optimized. The optimum pH range and flow rates for U(VI) and Th(IV) were 6.0-7.0 and 1.0-4.0 ml min⁻¹ and 3.5-4.5 and 1.5-4.0 ml min⁻¹, respectively. The total sorption capacity found for U(VI) and Th(IV) was 48734 and 41175 μg g⁻¹, respectively. Interference studies carried out in the presence of diverse ions and electrolyte species showed quantitative analyte recovery (98-98.5%) with lower limits of detection, 6.14 and 4.29 μg l⁻¹ and high preconcentration factors, 143 and 153 for U(VI) and Th(IV), respectively. The uptake and stripping of these metal ions on the resin were fast, indicating a better accessibility of the metal ions towards the chelating sites. The analytical applicability of the synthesized polymeric sorbent was tested with some synthetic mixtures for the separation of U(VI) and Th(IV) from each other and also from La(III), Cu(II) and Pb(II) by varying the pH and sequential acidic elution. The validity of the proposed method was checked by analyzing these metal ions in natural water samples, monazite sand and standard geological materials.