Thorium Ions Research Articles

Removal of thorium (IV) ions from aqueous solution by a novel nanoporous ZnO: Isotherms, kinetic and thermodynamic studies

The adsorption of thorium (IV) from aqueous solutions onto a novel nanoporous ZnO particles prepared by microwave assisted combustion was studied using batch methods under different experimental conditions. The effect of contact time, solution pH, initial concentration and temperature on adsorption process was studied. The ability of this material to remove Th (IV) from aqueous solution was characterises by Langmuir, Freunlinch and Temkin adsorption isotherms. The adsorption percent and distribution coefficient for nanoporous ZnO powders in optimum conditions were 97% ± 1.02; 8080 L kg−1for Th (IV), respectively. Based on the Langmuir model, the maximum adsorption capacity of nanoporous ZnO for Th (IV) was found to be 1500 g kg−1. Thermodynamic parameters were determined and discussed. The results indicated that nanoporous ZnO was suitable as sorbent material for recovery and adsorption of Th (IV) ions from aqueous solutions. The radioactive Th (VI) in surface water, sea water and waste waters from technologies producing nuclear fuels, mining (uranium and thorium) and laboratories working with radioactive materials (uranium and thorium) can be removed with this nanoporous ZnO.

Removal of thorium from water using modified magnetite nanoparticles capped with rosin amidoxime

The present study describes synthesis and characterization of diacrylamidoxime triaethylenetetralevopimaramide (DPAO) and its use in surface modification of Fe3O4 magnetic nanoparticles to obtain DPAO-based magnetic nanoparticles (DPAO-MNPs). The prepared composite was characterized by FTIR, 1HNMR, XRD, DLS, TEM, SEM and EDX. Vibrating sample magnetometer is used to determine the magnetic properties of DPAO-MNPs. Results of analyses indicate that the surface of Fe3O4 was successfully capped with DPAO. The adsorption features of the prepared composite towards thorium ions were investigated in a batch system. Kinetic study of Th(IV) adsorption on DPAO-MNPs indicate the adsorption equilibrium achieved within 150 min and is pH dependent. The adsorption results were described mathematically using Langmuir and Freundlich sorption models. The composite showed a maximum Th(IV) loading capacity of 666 mg/g at 25 °C and pH 4. The thermodynamic results indicated that the adsorption process was thermodynamically favorable, spontaneous and endothermic nature. The obtained results suggest that DPAO-MNPs composite may be considered as a potential fast, effective and simple adsorbent for sorption thorium(IV) from water.

Synthesis of ethylamine-bridged β-cyclodextrins and adsorption properties of thorium

A specialized ethylamine-bridged β-cyclodextrins (EB β-CD) was synthetized. EB β-CD’s adsorption properties of thorium ions were performed. Experimental results show that the adsorption of thorium using the EB β-CD can achieve equilibrium within 60 min at room temperature under the condition of pH 4, the adsorbance is 10.49 mg g−1. The results of SEM and BET nitrogen adsorption show that, EB β-CD is typical mesoporous material. According to pseudo-second-order kinetics, the adsorption of Th(IV) indicating the influence of textural properties of EB β-CD on the rate of adsorption. The thermodynamic parameters obtained showed that the adsorption process is exothermic, spontaneous process.

Biosorption characteristics of uranium(VI) and thorium(IV) ions from aqueous solution using CaCl2-modified Giant Kelp biomass

The CaCl2-modified Giant Kelp biomass (Ca-GK) showed a higher adsorption capacity for U(VI) and Th(IV) ions than the unmodified biomass. FTIR analysis indicates that carboxylic (as main adsorption sites), hydroxyl, sulfonate, and amino groups are responsible for U(VI) and Th(IV) adsorption. The kinetic analysis indicates that the rate-limiting step is the chemical sorption process. The maximum mono-layer adsorption capacities of Ca-GK in mono-component systems were 156 and 135 mg g−1 for U(VI) and Th(IV) ions, respectively. In bi-component systems, the adsorption capacities for both U(VI) and Th(IV) were reduced significantly, and the Ca-GK showed a slight adsorption preference for U(VI) over Th(IV).

Synthesis and Spectroscopic Characterization of Zr(IV) and Th(IV) With Chelating Containing ONNO Donor Quadridentate Schiff Bases Complexes

New metal complexes of novel Schiff bases derived from the reaction of zirconium (IV) and thorium (IV) ions with N,N′-disalicylidene-l,2-phenylenediamine (H2dsp), N,N′-disalicylidene-3,4-diaminotoluene (H2dst), 4-nitro-N,N-disalicylidene-1,2-phenylenediamine (H2ndsp) were prepared and characterized based on elemental analyses, IR and 1H NMR spectroscopy, molar conductance, and thermal analyses. The complexes are formed in 1:1 [Metal]:[Ligand] ratio. The molar conductance measurements proved that all these complexes are non-electrolytes. The IR spectra of the ligands and their complexes are used to identify the type of bonding. The thermogravimetric analysis of the complexes shows metal oxide remaining as the final product.

Multisectional linear ion trap and novel loading method for optical spectroscopy of electron and nuclear transitions.

There is a growing need for the development of atomic and nuclear frequency standards because of the important contribution of methods for precision time and frequency measurements to the development of fundamental science, technology, and the economy. It is also conditioned by their potential use in optical clocks and quantum logic applications. It is especially important to develop a universal method that could allow one to use ions of most elements effectively (including ones that are not easily evaporated) proposed for the above-mentioned applications. A linear quadrupole ion trap for the optical spectroscopy of electron and nuclear transitions has been developed and evaluated experimentally. An ion source construction is based on an ultra-high vacuum evaporator in which a metal sample is subjected to an electron beam of energy up to 1 keV, resulting in the appearance of gaseous atoms and ions of various charge state. The linear ion trap consists of five successive quadrupole sections including an entrance quadrupole section, quadrupole mass filter, quadrupole ion guide, ion-trap section, and exit quadrupole section. The same radiofrequency but a different direct current voltage feeds the quadrupole sections. The instrument allows the mass and energy selected trapping of ions from ion beams of various intensities and their localization in the area of laser irradiation. The preliminary results presented show that the proposed instrument and methods allow one to produce effectively up to triply charged thorium ions as well as to trap ions for future spectroscopic study. The instrument is proposed for future use in optical clocks and quantum logic application development.

Synthesis and Characterization of Thorium-doped Nd$lt;inf$gt;2$lt;/inf$gt;Zr$lt;inf$gt;2$lt;/inf$gt;O$lt;inf$gt;7$lt;/inf$gt; Pyrochlore

A2Zr2O7 zirconate pyrochlores are proposed as potential host phases for the immobilization of high level nuclear waste because of their chemical and radiation stabilities. Thorium-doped pyrochlore Nd1.8Th0.2Zr2O7.1 was synthesized at 1200 for 12 ℃ h by citrate polymer precursor method using zirconium nitrate, thorium nitrate, neodymium nitrate and citrate acid as raw materials. The phase compositions of the products were characterized by XRD, SEM, FT-IR and Raman spectrum. The results reveal that neodymium ions are substituted by thorium ions at the A position of A2Zr2O7, which maintain the single pyrochlore structure. The lat- tice parameter decreases for Nd2Zr2O7 pyrochlore with the addition of 20at% Th because the effective ionic ra- dius of Th 4+ is less than that of Nd 3+ . The mean grain sizes of these samples are about 50 nm and the bulk densi- ties are more than 95% of theoretical values. With thorium content increase, the degree of structural disorder in

Separation of thorium ions from wolframite and scandium concentrates using graphene oxide.

The separation of rare metals from the ores and commercially available compounds is an important issue due to the need of their high purity in advanced materials and devices. Important examples of two highly important elements that co-exist in the ores are scandium and thorium. Scandium containing ores and consequently also commercially available scandium compounds often contain traces of thorium which is very difficult to separate. We used graphene oxide for the selective sorption of thorium ions from scandium and thorium mixtures originating from the mined ores as well as from commercially available scandium salts. Our results showed that graphene oxide has an extreme affinity towards thorium ions. After the sorption process the graphene oxide contained over 20 wt% of thorium while the amount of scandium sorbed on GO was very low. This phenomenon of high sorption selectivity of graphene oxide can be applied in industry for the purification of various chemicals containing scandium and for separation of thorium containing mixtures. Alternatively, this methodology can be used for preconcentration of thorium from low-grade ores and its further use in the new generation of nuclear reactors.

Erratum to: Quadrupole Paul Ion Trap in Complex for Optical Spectroscopy of Multiply Charged Thorium Ions for the Development of a Nuclear Frequency Standard

Erratum to: Quadrupole Paul Ion Trap in Complex for Optical Spectroscopy of Multiply Charged Thorium Ions for the Development of a Nuclear Frequency Standard

Kinetic, equilibrium and thermodynamic studies on sorption of uranium and thorium from aqueous solutions by a selective impregnated resin containing carminic acid

In this work, the removal of uranium and thorium ions from aqueous solutions was studied by solid–liquid extraction using an advantageous extractant-impregnated resin (EIR) prepared by loading carminic acid (CA) onto Amberlite XAD-16 resin beads. Batch sorption experiments using CA/XAD-16 beads for the removal of U(VI) and Th(IV) ions were carried out as a function of several parameters, like equilibration time, metal ion concentration, etc. The equilibrium data obtained from the sorption experiments were adjusted to the Langmuir isotherm model and the calculated maximum sorption capacities in terms of monolayer sorption were in agreement with those obtained from the experiments. The experimental data on the sorption behavior of both metal ions onto the EIR beads fitted well in both Bangham and intra-particle diffusion kinetic models, indicating that the intra-particle diffusion is the rate-controlling step. The thermodynamic studies at different temperatures revealed the feasibility and the spontaneous nature of the sorption process for both uranium and thorium ions.

Sequestering of thorium ions from aqueous media on rice husk: Equilibrium, kinetic and thermodynamic studies

Abstract The adsorption behaviour of thorium on rice husk has been studied by optimizing different parameters like nature of electrolyte, amount of adsorbent, equilibration time, metal concentration, and temperature, employing batch method and radiotracer technique. Maximum adsorption was observed at 0.0001 mol L –1 HNO3, using 0.1 g of adsorbent for 4 cm3 of 5.19 · 10 –5 mol L –1 of Th+4 solution in fifteen minutes equilibration time. The adsorption phenomenon was verified by FTIR, SEM and EDX techniques. The adsorption data was well fitted to Freundlich, Langmuir and Dubinin-Radushkevich isotherm equations. The characteristic Freundlich constants i.e. 1/n = 0.528 ± 0.019 and K = 4.88 × 10−4 ± 1.29 · 10 –5 mol g –1 whereas the Langmuir constants Q m = (4.159 ± 0.234) × 10 –6 mol g –1 and K L = (3.627 ± 0.328) × 104 dm3 mol –1 have been computed for the sorption system. The sorption free energy was found to be 11.24 ± 0.211 kJ mol –1 showing chemisorption nature of interaction between thorium and rice husk. The results showed that thorium adsorption on rice husk follows pseudo 2nd order with rate constant = 1.448 g mg –1 min –1. The determined negative values of ΔG indicated spontaneity of the process, whereas the positive values of ΔH and ΔS confirmed endothermic nature and increased randomness during the adsorption process respectively. The removal of Th+4 ions from spiked tap water was checked by employing the optimized experimental parameters which indicated that rice husk is a good adsorbent for thorium ions and may be used for waste management of radionuclides.

Kinetic and isotherm analysis for selective thorium(IV) retrieval from aqueous environment using eco-friendly cellulose composite

Thorium reclamation was studied using nano-iron oxide-impregnated cellulose acetate beads to gain insights into the adsorption mechanism, kinetics and thermodynamics. The designed experiments were thoroughly investigated as a function of solution pH, initial thorium(IV) ion concentration, adsorbent dose and nano-iron oxide loading in the cellulose acetate matrix. The batch adsorption of Th(IV) ions revealed the highly pH dependent (pH range 3.0–9.0) behaviour with maximum sorption at pH 6.0 and equilibrium being achieved within 2 h for maximum concentration of 100 mg/L at 298 K. Rapid adsorption of 50 ± 0.2 % was observed within first 10 min. The kinetics data are best described by the pseudo-first-order kinetic model (R 2 = 0.9996) and intraparticle diffusion model. The equilibrium adsorption process was fitted with the Langmuir, Freundlich, Dubinin–Radushkevich and Temkin models which yield good fit with Langmuir isotherm equation indicating monolayer adsorption process. The calculated thermodynamics parameter reveals spontaneous and exothermic adsorption process. Further, the desorption was Th(IV) ions that was easily achieved using 0.05 N HNO3 which suggests the reusability of the adsorbent for multiple use.

Quadrupole Paul Ion Trap in Complex for Optical Spectroscopy of Multiply Charged Thorium Ions for the Development of a Nuclear Frequency Standard

Results from experimental designs intended for the creation of a laboratory model of a complex for optical spectroscopy of multiply charged thorium ions with a quadrupole Paul ion trap possessing a linear configuration for the development of a nuclear frequency standard are described. Preliminary experimental studies intended for the production of singly, doubly, and triply charged thorium ions from the solid-state compound thorium nitrate (IV) by the method of electron-beam evaporation are also presented. It is shown that, relative to singly charged ions, with the use of this method the fractions of triply and doubly charged thorium ions exceed the analogous values for the method of laser ablation used to produce these ions in laboratories in the United States and Germany. The method of electron-beam evaporation is made the basis of a newly developed complex for optical ultra-high resolution spectroscopy.

Simulation of the hot core mode of arc attachment at a thoriated tungsten cathode by an emitter spot model

Recently, a constricted attachment of an atmospheric pressure low-current argon arc in the centre of the flat end face of a thoriated tungsten cathode was observed and spectroscopically analysed. Its diameter of 0.6 mm and its length of the free standing part of 10 mm are the typical dimensions of electrodes for high-intensity discharge lamps. This paper gives a physical interpretation of the axially symmetric arc spot by a simulation of its properties with a cathodic sheath model which takes into account a reduction in the work function above a critical temperature of the cathode surface by a thorium ion current.At first the optical observation and spectroscopic investigations are recapitulated. Then, an overview is given on the essential elements which are needed to simulate the cathodic arc attachment on a hot electrode. A simulation of a central cathode spot with these elements gives results which are far away from the experimental findings if a constant work function φ is used. Therefore, a temperature-dependent work function φ(T) is introduced. This φ(T) transitions from 4.55 to 3 eV above temperatures of the order of 3000 K. With this emitter spot model a constricted arc attachment is obtained by simulation in the centre of the flat end face of the cathode in accordance with experiment. For currents below iarc,max ≈ 15.5 A, two spot solutions with different cathode falls are found. They form a current–voltage–characteristic consisting of two branches which extend from a turning point at iarc,max to lower currents. For iarc > iarc,max, only a diffuse mode of cathodic arc attachment is obtained. It is shown by a comparison with measured data for iarc = 7.5, 10, 12.5 and 15 A that the solution with the lower cathode fall is observed experimentally.

Synthesis, spectral, X-ray diffraction, antimicrobial studies, and DNA binding properties of binary and ternary complexes of pentadentate N2O3 carbohydrazone ligands

Two pentadentate carbohydrazone ligands, H2L1 and H2L2, were prepared by the reaction of the bifunctional compound carbohydrazide with 2-hydroxy-5-nitrobenzaldehyde and 2-hydroxy-1-naphthaldehyde, respectively. Reactions of the ligands with oxovanadium(IV), cerium(III), thorium(IV), and dioxouranium(VI) ions yielded binary complexes. Reactions of the ligands with the dioxouranium(VI) ion in the presence of secondary ligands (8-hydroxyquinoline, glycine, salicylaldehyde, or benzoylacetone) yielded ternary complexes. The ligands and metal complexes were characterized by different techniques such as elemental and thermal analyses, IR, 1H and 13C NMR, electronic, ESR, mass spectra, and powder XRD as well as magnetic susceptibility and conductivity measurements. The coordinating sites are phenolic oxygen, azomethine nitrogen, and carbonyl oxygen. In complexes, the ligands act as dibasic pentadentate except ternary dioxouranium(VI) complexes, obtained using glycine or benzoylacetone, in which the ligands act as monobasic pentadentate. The XRD patterns for the H2L1 ligand, its binary dioxouranium(VI) complex, and its 8-hydroxyquinoline ternary complex indicate crystalline nature and the grain size was estimated. The H2L1 ligand and its binary complex have triclinic systems while the ternary complex has a monoclinic system with different unit-cell parameters. The ligands and some of their metal complexes showed antimicrobial activity toward some Gram-positive and Gram-negative bacteria, yeast (Candida albicans), and fungus (Aspergillus fumigatus), and MIC values were determined. The DNA binding properties of the oxovanadium(IV) complexes of H2L1 and H2L2 ligands were investigated by electronic absorption spectroscopy and viscosity measurements. The results indicated that these complexes bind to DNA via an intercalation binding mode with an intrinsic binding constant K b of 2.55 × 104 and 3 × 104 M−1, respectively.

Th(IV) ion-imprinted polymer for selective solid-phase extraction of Th(IV) and its analytical applications

A new Th(IV) ion-imprinted polymer (IIP) was synthesized for the separation and recovery of trace Th(IV) ion from river water sample. Th(IV) IIP was prepared by copolymerization of methyl methacrylate (monomer) and ethylene glycol dimethacrylate (cross-linker) in the presence of Th(IV)-thiosemicarbazide-4-vinyl pyridine ternary complex wherein Th(IV) ion is the imprint ion and is used to form the imprinted polymer. Thorium(IV) ion was eluted with 10 mL of 1 M HCl. The polymers have been characterized by surface area measurements, fourier transform infrared spectroscopy, microanalysis and scanning electron microscopy analysis. The adsorption capacity of the imprinted polymer was found to be 0.290 mmol g−1, which is much higher than most of the reported IIPs. The optimum pH for quantitative enrichment is 4.0. The relative selectivity coefficient values of the imprinted polymer for Th(IV)/Pb(II), Th(IV)/Zn(II), Th(IV)/Cu(II), Th(IV)/Ni(II), Th(IV)/Cd(II) and Th(IV)/Co(II) are 37.13, 37.40, 30.34, 35.69, 37.63 and 36.28, respectively. The lowest concentration that could be determined by Arsenazo III spectrophotometric method below which the recovery becomes non-quantitative is 5 μg L−1.

Separation and direct UV detection of complexed lanthanides, thorium and uranyl ions with 2-thenoyltrifluoroacetone by using capillary zone electrophoresis

Separation and detection of lanthanides, thorium and uranyl ions by capillary zone electrophoresis in the presence of 2-thenoyltrifluoroacetone (HTTA) as UV-absorbing complexing agent were investigated. The separation of positively charged complexes is partially improved by using a competing ligand in buffer with HTTA for metal ions. When 2-hydroxyisobutyric acid (HIBA) is used as competing ligand, complete separation of thorium, uranyl and lanthanides ions were observed. Some separation parameters such as pH value, the concentration of carrier electrolyte, applied voltage, the concentration of ligand in buffer and the temperature were also optimized. Under the selected conditions, the complete separation of thorium and uranyl from each other and from lanthanides was accomplished in only 12 min using 1 mmol/L HTTA, 50 mmol/L HIBA, 5 mmol/L NaNO3, 5 % methanol with a pH 5.2 at a capillary temperature of 25 °C. Direct photometric detection at 210 nm using a voltage of 25 kV and an electrokinetic injection (100 mm for 6 s) were used.

Adsorption of thorium (IV) ions from aqueous solution by magnetic chitosan resins modified with triethylene-tetramine

The triethylene-tetramine modified magnetic chitosan sorbents (TETA-MCS) were synthesized for the adsorption of Th(IV) ions from aqueous solution. FTIR analysis indicated that the amine and hydroxyl groups of TETA-MCS were involved in the adsorption process for the formation of O, N–Th(IV) complex. Th(IV) adsorption was pH dependent and the maximum adsorption was observed at pH 4.0. The adsorption kinetic data could be interpreted by pseudo-second-order kinetic model. The equilibrium data were correlated with the Langmuir, Freundlich and Temkin models, and the maximum monolayer adsorption capacity obtained from the Langmuir model was 133.3 mg Th(IV)/g at 25 °C. Thermodynamic parameters revealed the feasibility, spontaneity and endothermic nature of adsorption. The sorbents were successfully regenerated using 0.2 M HNO3−0.1 M EDTA and exhibited good reusability.

Competitive adsorption of uranium(VI) and thorium(IV) ions from aqueous solution using triphosphate-crosslinked magnetic chitosan resins

The triphosphate-crosslinked magnetic chitosan resins (TPP-MCR) with a diameter range of 200–350 nm were synthesized for the adsorption of U(VI) and Th(IV) ions from aqueous solutions. The adsorption experiments were conducted in both mono-component systems with pure actinide solution and bi-component systems with different U/Th mass ratios. The maximum adsorption capacities in mono-component systems determined by Langmuir model were 169.5 and 146.8 mg g−1 for U(VI) and Th(IV), respectively. In bi-component systems, U(VI) and Th(IV) adsorption capacities were reduced significantly, and the combined sorption capacities were substantially lower (almost halved) compared to those obtained by the addition of sorption capacities using mono-component solutions, indicating that U(VI) and Th(IV) compete for the same sorption sites. Adsorption–desorption experiments for five cycles illustrated the feasibility of the repeated use of TPP-MCR for the adsorption of U(VI) and Th(IV) ions.

Adsorptive Removal of Thorium(IV) from Aqueous Solutions Using Synthesized Polyamidoxime Chelating Resin: Equilibrium, Kinetic, and Thermodynamic Studies

In this study, an amidoximated chelating ion exchange resin was prepared by poly-acrylonitrile (PAN) grafted potato starch. The adsorbent characterizations such as specific surface area, pore volume, average pore radius, and Fourier transform infrared (FTIR) spectrum of the resin were measured. The effects of pH, adsorbent dosage, contact time, initial concentration of thorium ion, and temperature on adsorption of thorium ion from aqueous solutions were investigated. Four isotherm models including Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin were applied to analyze the equilibrium isotherm data. The results showed that Langmuir and Temkin models had a good agreement with experimental data. The maximum capacity of the adsorbent using the Langmuir isotherm model was 227.27 mg · g−1. The kinetic models like pseudo-first-order, pseudo-second-order, Elovich, and intraparticle were examined to describe the adsorption process. The kinetics of the adsorption process was found to follow the pseudo-second-order kinetic model. The thermodynamic parameters (ΔG°, ΔH°, ΔS°) were also calculated using equilibrium constant values at various temperatures (25, 35, 45, 55°C) and the positive value for ΔH° showed an endothermic adsorption process. The study suggests that the prepared adsorbent has promising potential for the removal of thorium from wastewaters.