Sorption Of Strontium Ions Research Articles

Sorption of Strontium Ions on Potassium-Titanate Nanotubes Doped with Magnesium

Sorption of Strontium Ions on Potassium-Titanate Nanotubes Doped with Magnesium

Sorption of Strontium Ions on Barium Silicates from Solutions of Complex Salt Composition

The comparative analysis of sorption properties of nanostructured barium silicates obtained in multicomponent systems BaCl2 · 2H2O–КОН–SiO2–H2O and BaCl2 · 2H2O–КОН–SiO2–AlCl3–H2O has been performed to extend previous data; the data on the composition and morphology of the systems have been presented. Their properties toward sorption of Sr2+ ions from solutions of complex ionic composition have been studied. It has been found that synthetic barium silicates and alumosilicates have high sorption and kinetic characteristics under static sorption conditions. The maximal degree of Sr2+ ions recovery from solutions of complex composition (>99%) was achieved for barium silicate BaSiO3 · 2.3H2O. The samples of barium alumosilicate BaAl2Si2O8 · 2.6H2O have the same sorption characteristics within measurement error. It has been shown that the studied sorbents, allowing for their kinetic properties, may be recommended for the deep purification of solutions of complex ionic composition, seawater including, from strontium ions under static conditions.

Sorption of Strontium Ions on Potassium-Titanate Nanoparticles of Various Morphology Obtained under Hydrothermal Conditions

The results of the study of the interaction of an aqueous solution of strontium nitrate with potas-sium-titanate nanoparticles of different morphology obtained by the hydrothermal method are reported. Comparative analysis showed the advantage of nanotubes as sorbents over nanolayers and nanowires. As can be seen from the experiment conducted with nanotubes containing aluminum, an amount of strontium sorbed from the solution rises with increasing temperature: at 50°C the absorption by the tubular matrix was ≈ 0.76 × 10−3 mol g−1, and at 80°C that was ≈ 2.02 × 10−3 mol g−1. Nanotube samples doped with magnesium had the best sorption characteristics: After 5 h of keeping in a solution at 80°С, the content of strontium in them was ≈3.65 × 10−3 mol g−1. The results show the promise of using potassium titanate nanoparticles to extract strontium from aqueous solutions.

Simultaneous Adsorption and Incorporation of Sr2+ at the Barite (001)–Water Interface

Ionically bonded minerals are ubiquitous and play a determinative role in controlling the mobility of toxic metals in natural environments. However, little is known about the mechanism of ion uptake by these mineral surfaces. Here, the sorption of strontium ions (Sr2+) to the barite (001)–water interface was studied using a combination of synchrotron X-ray scattering and three types of computational simulations (density functional theory, classical molecular dynamics (CMD), and CMD-metadynamics). In situ resonant anomalous X-ray reflectivity (RAXR) revealed that Sr2+ adsorbed on the barite surface as inner-sphere surface complexes and was incorporated within the outermost barite atomic layers. Density functional theory combined with CMD simulations confirmed the thermodynamic stability of these species, demonstrating almost equal magnitudes in the free energy of sorption between these species. Metadynamics simulations showed a more detailed feature in the free energy landscape for metal adsorption where a...

Biosorption of strontium ions from aqueous solution using modified eggshell materials

Abstract Green composites emphasize renewable starting materials for better economy using biomass materials. Therefore, low-cost composite biosorbent was prepared by modification of eggshell material using heteropoly acid for removal of strontium ions from aqueous solution. The resulted composite was characterized and evaluated for the sorption process using the batch technique. Low concentration of strontium ions was used to evaluate the sorption sensitivity of the prepared composite. The obtained experimental results illustrated that the modification process of eggshell material enhanced the percent uptake from 49.9 to 95.7%. From kinetic studies, the sorption of strontium ions follows the pseudo-second-order kinetic model. The isotherm studies indicated that Langmuir is more applicable than Freundlich isotherm. Moreover, Dubinin–Radushkevich isotherm was studied. Thermodynamic studies revealed that the sorption process is spontaneous and has endothermic nature. Strontium ions can be desorbed from the modified eggshell using HNO3, desorption percent was found to be 96.4%; the results revealed the reusability of the modified eggshell for further sorption.

Sorption of strontium ions from solutions onto calcium and magnesium phosphates

A comparative study of the uptake of Sr ions from aqueous solutions with calcium and magnesium phosphates of various chemical compositions was made. Calcium and magnesium phosphates in the concentration range 10–5000 mg L−1 absorb up to 280 mg g−1 Sr, with the ability of magnesium phosphates to take up Sr ions exceeding that of calcium phosphates by an order of magnitude. The degree of decontamination of solutions from 90Sr with the magnesium-containing samples exceeds 80%, and the distribution coefficient is (4.7–5.4) × 103 cm3 g−1.

Sorption of strontium ions from aqueous solutions by oxidized multiwall carbon nanotubes

Multiwall carbon nanotubes (MWCNTs) oxidized by nitric acid solution were used to investigate the adsorption behavior of strontium from aqueous solutions similar to the nuclear waste media. The physical properties of both as produced and oxidized MWCNTs were studied by Boehm’s titration method and nitrogen adsorption/desorption. The results showed that the surface properties of MWCNTs such as specific surface area, functional groups and the total number of acid sites were improved after oxidation. Furthermore, the effect of solution conditions such as initial concentration of strontium(II), pH, ionic strength, MWCNT concentration and contact time were studied at room temperature. The results of this study showed that the adsorption of strontium(II) was significantly influenced by the pH value and the solution ionic strength. According to the Langmuir model, the maximum adsorption capacities of strontium(II) onto the as produced and oxidized MWCNTs were obtained as 1.62 and 6.62 mg g−1, respectively. The contact time to reach equilibrium was 100 min. The good adsorption of strontium(II) on oxidized MWCNTs at the lower ionic strength, the relatively high pH and the short equilibrium time indicate that the oxidized MWCNTs have great potential applications in the field of the environmental protection.

Isotherm of Strontium Sorption on Clay

Sorption of strontium(II) with soil components from model solutions was studied. Limiting sorption of strontium ions, their landing site area, and Langmuir constants were determined.

A study of the sorption of strontium ions on α-FeOOH

The sorption of strontium ions on the solid liquid interface of the α-FeOOH-0.1M-NaNO3 system was studied over a wide concentration region of strontium ions and a constant concentration of sorbent so that crel = csorbent/csorbate was 101-104. The ΔG value of the sorption varies with crel and pH; it is as low as -32 kJ mol-1 at crel = 10 000 and pH 11 and increases to -18 kJ mol-1 at crel = 10 and pH 7.5. None of the conventional sorption equations can be applied to the studied system over the entire concentration region, but an equation of a different form is suggested for the description of this system.

Sorption of radiactive strontium on binary systems of some alkaline earth sulfates

Equilibrium and metastable solid solutions of binary mixtures of BaSO4−CaSO4 and SrSO4−CaSO4, and sorbents based on mixtures of compounds in the systems BaSO4−MgSO4 and SrSO4−MgSO4 were prepared by special heat treatments. The sorption properties of such systems were studied in relation to their structural characteristics. A positive effect of the dynamic reconstruction of the lattice on the sorption of strontium ions was found in all cases. Good sorption properties were found for the systems BaSO4−CaSO4 and BaSO4−MgSO4 An effort was made to explain the mechanism of sorption on such systems, using several independent methods.