Sorption behaviour of lanthanum(III), neodymium(III), terbium(III), thorium(IV) and uranium(VI) on Amberlite XAD-4 resin functionalized with bicine ligands

The complexing properties (capacity, pH effect, breakthrough curve) of a chelating resin, containing bicine ligands, were investigated for La(III), Nd(III), Tb(III), Th(IV) and U(VI). Trace amounts of these metal ions were quantitatively retained on the resin and recovered by eluting with 1 M hydrochloric acid. The capacity of the resin for La(III), Nd(III), Tb(III), Th(IV) and U(VI) was found to be 0.35, 0.40, 0.42, 0.25 and 0.38 mmol g(-1), respectively. Separation of U(VI) and Th(IV) from Ni(II), Zn(II), Co(II) and Cu(II) in a synthetic solution was carried out.     

Comparative study on lanthanum(III) sorption onto Lewatit TP 207 and Lewatit TP 260

Batch experiments are carried out for the sorption of La(III) onto commercial macroporous resins containing iminodiacetic (Lewatit TP 207) and aminomethylphosphonic acid groups (Lewatit TP 260). The operating variables studied are initial La(III) concentration, pH, temperature and contact time. Since the extraction kinetics were fast, with a mixture of 0.1 g of resin and 5 mL of lanthanum ions 0.5 × 10^?3 mol L^?1 solution, extraction equilibrium was reached within 30 min of mixing. The optimum pH values level for quantitative sorption were between 1.5 and 4.6 with Lewatit 207 and about 5.2 with Lewatit TP 260. The sorption capacities of Lewatit TP 207 and Lewatit TP 260 resins are 114.7 and 106.7 mg g^?1, respectively. Adsorption equilibrium data were calculated for Langmuir and Freundlich isotherms. It was found that the sorption of La(III) on Lewatit TP 207 was better suited to the Langmuir adsorption model while Freundlich adsorption model fitted better sorption on Lewatit TP 260. Thermodynamics data leads to endothermic and spontaneous process. ΔG° decreases with increasing temperature indicating that sorption process of La(III) on both Lewatit TP 207 and Lewatit TP 260 was more favored at high temperature.     

Solid-phase extractive preconcentration and separation of lanthanum(III) and cerium(III) using a polymer-supported chelating calix [4] arene resin

In the present paper, solid-phase extractive preconcentration and separation of lanthanum(III) and cerium(III) using calix[4]arene-o-vanillinsemicarbazone immobilized on a polymeric matrix, a Merrifield peptide resin, is proposed. The diamino derivative of calix[4]arene was first diazotized and coupled with o-vanillinsemicarbazone to obtain a new “upper-rim” functionalized calix[4]arene-o-vanillinsemicarbazone. It was then covalently linked to the Merrifield peptide resin and characterized by FT-IR and elemental analysis. Quantitative studies were carried out by spectrophotometry and ICP-AES with a relative standard deviation of 1.7%. Various physicochemical parameters like pH, concentration of eluting agents, flow rate, total sorption capacity, metal-ligand stoichiometry, exchange kinetics, preconcentration factor, distribution coefficient, breakthrough capacity, resin stability, and effect of electrolytes and associated metal ions have been studied. The uptake and stripping of these metal ions on the resin was fast, indicating a better accessibility of La(III) and Ce(III) towards the chelating sites. Detection limits corresponded to three times the standard deviation of the blank (3σ_B) and amounted to 3.05 and 6.86 μg/L, along with preconcentration factors of 153 and 133 for La(III) and Ce(III), respectively. The robustness of the procedure is demonstrated by the recoveries obtained (>97.5%) for La(III) and Ce(III) in the presence of several cations and anions. The proposed method was satisfactorily applied to the separation of La(III) and Ce(III) from each other and also from U(VI) and Th(IV) by sequential acidic elution and varying pH. The validity of the method was tested by analyzing these metal ions in monazite sand and standard geological materials. The text was submitted by the authors in English.     

Sorption of La(III) and Ce(III) by oxidized carbon nanotubes

The ion-exchange sorption of La(III) and Ce(III) from nitrate solutions using oxidized carbon nanotubes with a solubility of 4.2 g/L is studied at metal concentration С = 5–160 mg/L, рН 2.5–6.0, ratio S: L = 0.002–0.06, and room temperature. At С = 35 mg/L, the equilibrium capacity is shown to grow dramatically with рН rising from 3.0 to 4.0–4.5 and reaching 840 mg/g in La and 950 mg/g in Се when S: L < 0.006 and рН > 4.0–4.5. The introduction of ionic salts is found to reduce the capacity (at рН > 4 and concentrations of 0.01 М and 0.1 М NaCl, the Се capacity is reduced to ~500 and ~200 mg/g). It is concluded that the sorption equilibrium is better described by the Langmuir equation, while the process kinetics, by pseudo-first and pseudo-second order equations.     

Extraction of Nd(III), Tb(III) and Lu(III) with picrolonic acid in methylisobutylketone

The extraction of Nd(III), Tb(III) and Lu(III) as representatives of lanthanide(III) ions with picrolonic acid (HPA) in methylisobutylketone (MIBK) has been studied from pH 1-2 buffer solutions. The composition of the organic species formed in the organic phase after extraction has been determined by slope analysis to be M(PA)₃ [M = Nd(III), Tb(III) and Lu(III)]. The equilibrium constant values, log k _ex This revised version was published online in July 2006 with corrections to the Cover Date.     

Sorption of Lanthanum(III) by Natural Mordenite-containing Tuff

The equilibrium in the mordenite-containing tuff-lanthanum(III) solution system was studied within a wide metal concentration range (1-2000 g ml^-1). Kinetic parameters of La(III) sorption were determined.     

Construction of a Highly Selective and Sensitive La(III) Sensor Based on N‐(2‐Pyridyl)‐N′‐(4‐methoxyphenyl)‐thiourea for Nano Level Monitoring of La(III) Ions

N‐(2‐Pyridyl)‐N′‐(4‐methoxyphenyl)‐thiourea (PMPT) was found to be a suitable neutral ion carrier for the construction of a highly selective and sensitive La(III) membrane sensor. Poly(vinyl chloride) (PVC) based membranes of PMPT with potassium tetrakis (p‐chlorophenyl) borate (KTpClPB) as an anionic excluder and oleic acid (OA), dibutyl phthalate (DBP), benzyl acetate (BA) and o‐nitrophenyloctyl ether (NPOE) as plasticizing solvent mediators were constructed and investigated as La(III) membrane sensors. A membrane composed of PMPT‐PVC‐KTpClPB‐BA with the ratio 8.0 : 35.0 : 3.0 : 54.0 works well over a very wide concentration range (4.0×10^?8 to 1.0×10^?1 M) with a Nernstian slope of 19.6±0.2 mV per decade of activity between pH values of 4.0 and 9.0. The detection limit of the sensor was calculated to be 2.0×10^?8 M (ca. 3.0 ppb). The sensor displays very good discrimination toward La(III) ions with regard to most common metal ions and lanthanide ions. The proposed sensor shows a short response time for whole concentration range (ca. 12 s). For evaluation of the analytical applicability of the La(III) sensor, it was successfully used as an indicator electrode for the titration of La(III) ions with EDTA. It was also applied to the determination of fluoride content of two mouth wash preparation samples and monitoring of La(III) ions in some binary and ternary mixtures.     

Removal of La(III) by amino-phosphonic acid functionalized polystyrene microspheres prepared via electron beam irradiation

A new aminophosphonic acid chelating resin was successfully prepared via electron beam irradiation grafting combined with chemical modification and used for the efficient removal of La(III). Firstly, glycidyl methacrylate (GMA) was grafted to polystyrene microspheres (PS) via electron beam co-radiation to obtain PS-PGMA microspheres, then followed by the amination with diethylenetriamine (DETA) to formed PS-PGMA-DETA (PGD) microspheres through nucleophilic substitution between amino and epoxy group, and finally PS-PGMA-DETA-PA (PGDP) microspheres was obtained by phosphorylation with phosphorous acid (PA). The obtained chelating resin absorbent was characterized by Fourier-transform infrared (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), which demonstrated that the millimetric aminophosphonic acid chelating resin were successfully prepared with well-defined morphology and enhanced thermal stability. The X-ray photoelectron spectroscopy (XPS) characterization results confirmed a possible adsorption mechanism, which is mainly based on the chelation and coordination of N and O in PDGP with La(III) in the solution. A series of parameters were taken into account in the adsorption experiment, such as absorbed dose, GMA concentration, dosage of PGDP, pH, contact time, temperature, and the initial concentrations of La(III). The maximum adsorption capacity obtained from the research can be achieved 288.69 mg/g at 298.15 K, pH = 6. The kinetic sorption for for La(III) fitted the type 1 pseudo-second-order (R² = 0.9981), which revealed that the La(III) are chemisorbed on the surface of the PGDP. It was concluded that the La(III) adsorption conformed to the Freundlich equation, indicating a multilayer adsorption process. Thermodynamic data indicated that the La(III) uptake process was a spontaneous and endothermic. In addition, this research provided a new irradiation grafting method for rare earth ions removal.     

Potentiometric determination of neodymium (III) ions using tin (IV) antimonotungstate and zirconium (IV) antimonotungstate as electro-active materials

Neodymium (III)-selective electrodes have been prepared by using tin (IV) antimonotungstate (SnSbW) and zirconium (IV) antimonotungstate (ZrSbW) as electro-active materials and epoxy resin as a binding material. In the case of SnSbW, best performance is exhibited by a membrane having the composition: tin (IV) antimonotungstate (50%) and epoxy resin (50%). It shows excellent response in the concentration range of 10^–4?M to 10^–1?M Nd (III) ion with a super-Nernstian slope of 40.0?mV/decade. It has a fast response time of 20 seconds and can be used for at least six months without any considerable divergence in potential. In the case of ZrSbW, best performance is exhibited by a membrane having the composition: zirconium (IV) antimonotungstate (40%) and epoxy resin (60%). It shows excellent response in the concentration range of 10^–5?M to 10^–1?M Nd (III) ion with a near-Nernstian slope of 25.0?mV/decade. It has a fast response time of 10 seconds and can be used for at least six months without any considerable divergence in potential. Effect of internal solution has been studied and the electrode was successfully used in partially non-aqueous medium, too. Selectivity coefficients have been determined by FIM method, with respect to alkali, alkaline earth, some transition and rare earth metal ions. ZrSbW electrode can be used in the pH range of 2.9–9.9 and SnSbW shows pH range 3.0–9.0. Both the electrodes have been used as indicator electrodes in the potentiometric titration of Nd (III) ions against EDTA.     

Separation and preconcentration of gallium(III), indium(III), and thallium(III) using new hydrazone-modified resin.

Ga(III), In(III) and Tl(III) ions in the presence of different sulfate salts have been successfully separated using 1-(3,4-dihydroxybenzaldehyde)-2-acetylpyridiniumchloride hydrazone (DAPCH) loaded on Duolite C20 in batch and column modes. The obtained modified resin as well as the metal complexes was characterized by elemental analysis and infrared spectra. The extraction isotherms were determined at different pH values. Ga(III) and In(III) are sorbed from aqueous solution at pH 2.5 - 3.0 while Tl(III) is sorbed at 2.0. The stripping of the adsorbed ions can be carried out using different concentrations of HCl as eluent. The saturation sorption capacities of Ga(III), In(III) and Tl(III) were 0.82, 0.96 and 0.44 mmol g(-1), where the preconcentration factors are 150, 150 and 100, respectively. The metal(III):Duolite C20-DAPCH ratio was 1:2 for Tl(III) and 1:1 for In(III) and Ga(III). The loaded resin can be regenerated for at least 50 cycles. The utility of the modified resin was tested in aqueous samples and the results show an RSD value of < 5% reflecting their accuracy and reproducibility.     

Sorption and desorption of Eu(III) on alumina

Summary Effects of ionic strength and of fulvic acid on the sorption of Eu(III) on alumina were investigated by using a batch technique. The experiments were carried out at T=25±1 °C, pH 4-6 and in the presence of 1M NaCl. The results indicate that sorption isotherms of Eu(III) are linear at low pH values. The sorption-desorption of Eu(III) on alumina at pH 4.4 is reversible, but a sorption-desorption hysteresis is found at pH 5.0. Fulvic acid has an obvious positive effect on the sorption of Eu(III) on alumina at low pH values. The migration of Eu(III) in alumina was studied by using column experiments and ^152+154Eu(III) radiotracer at pH 3.8. For column experiments, Eu(III) sorbed on alumina can be desorbed completely from the solid surface at low pH values. The findings are relevant to the evaluation of lanthanide and actinide ions in the environment.     

Amberlite XAD-4 functionalized with m-phenylendiamine: Synthesis, characterization and applications as extractant for preconcentration and determination of rhodium (III) in water samples by Inductive Couple Plasma Atomic Emission Spectroscopy (ICP-AES)

A new chelating resin is prepared by coupling Amberlite XAD-4 with metaphenylendiamine through an azo spacer, characterized (elemental analysis, IR and thermogravimetric analysis (TGA)) and studied for preconcentration Rh (III) using Inductive Couple Plasma Atomic Emission Spectroscopy (ICP-AES) for rhodium monitoring. The optimum pH value for sorption of the metal ion was 6.5 (recovery 100%). The sorption capacity was found 0.256 mmol g^− 1 of resin for Rh (III). The method has a detection limit and limit of quantification of 0.05 and 0.08 μg mL^− 1 at pH 6.5, respectively. The chelating resin can be reused for 10 cycles of sorption-desorption without any significant change in sorption capacity. A recovery of 100% was obtained for the metal ion with 1.5 M HCl as eluting agent. The equilibrium adsorption data of Rh (III) on modified resin were analyzed by Langmuir and Freundlich models. Adsorption data were modeled using the pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetics equations. Isotherms have also been used to obtain the thermodynamic parameters such as free energy, enthalpy and entropy of adsorption. The positive value of the enthalpy change (2.48 kJ/mol) indicates that the adsorption is an endothermic process. The method was applied for rhodium ions determination from tap water sample.     

Chromatographic separation of In(III) from Cd(II) in aqueous solutions using commercial resin (Dowex 50W-X8)

This work assesses the potential of an adsorptive material, Dowex 50w-x8, for the separation of indium ions from cadmium ions in aqueous media. The adsorption behavior of Dowex 50 w-x8 for indium and cadmium ions was investigated. The effect of pH, initial concentration of metal ions, the weight of resins, and contact time on the sorption of each of the metal ions were determined. It was found that the adsorption percentage of the indium ions was more than 99% at pH 4.0. The result shows that In (III) was most strongly extracted, while Cd(II) was slightly extracted at this pH value. The recovery of In(III) and Cd(II) ions is around 98% using hydrochloric acid as the best eluent.      

Amberlite XAD-7 impregnated with Xylenol Orange: a chelating collector for preconcentration of Cd(II), Co(II), Cu(II), Ni(II), Zn(II) and Fe(III) ions prior to their determination by flame AAS

A new chelating resin, Xylenol Orange coated Amberlite XAD-7, was prepared and used for preconcentration of Cd(II), Co(II), Cu(II), Fe(III), Ni(II) and Zn(II) prior to their determination by flame atomic absorption spectrophotometry. The optimum pH values for quantitative sorption of Cd(II), Co(II), Cu(II), Fe(III), Ni(II) and Zn(II) are 4.5-5.0, 4.5, 4.0-5.0, 4.0, 5.0 and 5.0-7.0, respectively, and their desorptions by 2 mol L(-1) HCl are instantaneous. The sorption capacity of the resin has been found to be 2.0, 2.6, 1.6, 1.6, 2.6 and 1.8 mg g(-1) of resin for Cd, Co, Cu, Fe, Ni and Zn, respectively. The tolerance limits of electrolytes, NaCl, NaF, NaI, NaNO3, Na2SO4 and of cations, Mg2+ and Ca2+ in the sorption of the six metal ions are reported. The preconcentration factor was between 50 and 200. The t1/2 values for sorption are found to be 5.3, 2.9, 3.2, 3.3, 2.5 and 2.6 min for the six metals, respectively. The recoveries are between 96.0 and 100.0% for the different metals at preconcentration limits between 10 to 40 ng mL(-1). The preconcentration method has been applied to determine the six metal ions in river water samples after destroying the organic matter (if present in very large amount) with concentrated nitric acid (RSD < or = 8%, except for Cd for which it is upto 12.6%) and cobalt content of vitamin tablets with RSD of approximately 3.0%.     

Analytical application of poly[dibenzo-18-crown-6] for column chromatographic separation of Nd(III) from Ce(III), U(VI) and other elements

This research is dedicated to the study of analytical application of poly[dibenzo-18-crown-6] for separation of Nd(III) from possible lanthanides, actinides and other metal ions. A simple and efficient column chromatographic method has been developed using poly [dibenzo-18-crown-6] as stationary phase and hippuric acid as a counter ion. The capacity of crown polymer for Nd(III) was found to be 0.55 ± 0.01 mmol/g. Nd(III) was quantitatively separated from Ce(III), U(VI) and other elements in binary as well as multicomponent mixtures. Separation yields were good and reproducible (±2 %). This method has important application for separation of Nd(III) from Ce(III) rapidly and selectively.     

Synthesis and Application of Co‐Poly(2‐hydroxyethyl methacrylate‐ethylene dimethacrylate) Coupled with Alizarin Yellow for Preconcentration and Determination of Lead in Water Samples by Flame Atomic Absorption Spectrometry

Poly(2‐hydroxyethyl methacrylate‐ethylene dimethacrylate) (PHEMA‐EDMA) beads were produced by free radical co‐polymerization of 2‐hydroxyethyl methacrylate (HEMA) and ethylene dimethacrylate (EDMA). Then, metal complexing ligand alizarin yellow was covalently attached onto PHEMA‐EDMA beads. The resulting resin has been characterized by FT‐IR and studied for the preconcentration and determination of trace Pb(II) ion from solution samples. The optimum pH value for sorption of the metal ion was 5. The sorption capacity of functionalized resin is 100 mg.g^‐1. The chelating resin can be reused for 20 cycles of sorption‐desorption without any significant change in sorption capacity. A recovery of 96% was obtained for the metal ion with 0.1 M nitric acid as eluting agent. The equilibrium adsorption data of Pb(II) on modified resin were analyzed by Langmuir and Freundlich models. Based on equilibrium adsorption data the Langmuir and Freundlich constants were determined 2.571 and 418.7 at pH 5 and 25 °C. The method was applied for lead ions determination from well water sample.     

A chelating resin containing 1-(2-thiazolylazo)-2-naphthol as the functional group; synthesis and sorption behavior for trace metal ions

A new polystyrene-divinylbenzene resin containing 1-(2-thiazolylazo)-2-naphthol (TAN) functional group was synthesized and its sorption behavior for 19 metal ions including Zr(IV), Hf(IV) and U(VI) was investigated by batch and column experiments. The chelating resin showed a high sorption affinity for Zr(IV) and Hf(IV) at pH 2. Some parameters affecting the sorption of the metal ions are detailed. The breakthrough and overall capacities were measured under optimized conditions. The overall capacities of Zr(IV) and Hf(IV) that were higher than those of the other metal ions were 0.92 and 0.87 mmol/g, respectively. The elution order of metal ions at pH 4 was evaluated as: Zr(IV)>Hf(IV)>Th(IV)>V(V)>Nb(V)>Cu(II)>U(VI)>Ta(V)>Mo(VI)>Cr(III)>Sn(IV)>W(VI). Quantitative recovery of most metal ions except Zr(IV) was achieved using 2 M HNO₃. Desorption and recovery of Zr(IV) was successfully performed with 2 M HClO₄ and 2 M HCl.     

Sorption of praseodymium(III) ions from aqueous solutions by a natural clinoptilolite-containing tuff

The equilibrium and kinetics of sorption of praseodymium(III) ions from sulfate solutions by a natural clinoptilolite-containing tuff are studied. It is shown that praseodymium is completely extracted from dilute solutions (<0.002 M). The kinetic parameters of the sorption process are determined.     

Mutual separation of Co(II), Fe(III), Eu(III) and Tb(III) on HTTA-loaded polyurethane foam

The selectivity of the 2-thenoyltrifluoroacetone (HTTA) loaded polyurethane (PUR) foam as adsorbent was studied. The influence of various anions on the adsorption indicated that permanganate, oxalate, EDTA, and citrate formed strong complexes with the metal ions and masked completely, while phosphate, thiosulphate, cyanide, ascorbate, tartrate and fluoride hindered the sorption of Fe(III). The sorption of Co(II) is also prohibited in presence of anions like cyanide, ascorbate and tartrate. The sorption of Eu(III) and Tb(III) is greatly affected in the presence of phosphate and fluoride. A group separation of different metals has been proposed on the basis of selectivity of the foam.     

Preparation and properties of a new chelating resin containing 1-nitroso-2-naphthol as the functional group

A macroreticular polystyrene-based chelating ion-exchanger containing 1-nitroso-2-naphthol as the functional group has been synthesized. The exchange-capacity of the resin for a number of metal ions such as copper(II), iron(III), cobalt(II), nickel(II), palladium(II) and uranium(VI) as a function of pH has been determined. The sorption and elution characteristics for palladium(II) and uranium(VI) have been thoroughly examined with a view to utilizing the resin for separation and concentration of uranium and palladium. Uranium(VI) has been separated from a mixture of ten other metal ions by sorption on the chelating resin and selective elution with 0.5M sodium carbonate. Palladium(II) has been separated from various metal ions by selective sorption on the resin in 1M hydrochloric acid medium.