Elaboration of Impregnated Composite for Sorption of Europium and Neodymium Ions from Aqueous Solutions (original) (raw)
Polymers
The escalating demand for rare earth metals (REM) in situations of limited availability has spurred scientists to seek alternative sources of REM, such as industrial waste solutions. This paper investigates the potential for improving the sorption activity of readily available and inexpensive ion exchangers, specifically the interpolymer systems “Lewatit CNP LF and AV-17-8”, towards europium and scandium ions, in comparison to the unactivated ion exchangers. The sorption properties of the improved sorbents (interpolymer systems) were evaluated using conductometry, gravimetry, and atomic emission analysis. The results demonstrate that the “Lewatit CNP LF:AV-17-8” (5:1) interpolymer system exhibits a 25% increase in europium ion sorption compared to the raw Lewatit CNP LF (6:0), and a 57% increase in europium ion sorption compared to the raw AV-17-8 (0:6) ion exchanger after 48 h of the sorption process. In contrast, the “Lewatit CNP LF:AV-17-8” (2:4) interpolymer system exhibits a 31...
Journal of Radioanalytical and Nuclear Chemistry, 1997
Extraction chromatographic supports (XAD-7) impregnated with binary mixtures of cobalt dicar and one of the two phosphororganic extractants (dibutyl-N,N-diethylcarbamoyhnethyl phosphonate, DBDECMP, or octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide, (CMt~) were prepared using methanofic solutions of the extractants and subsequent evaporation of methanol at room temperature. The molar ratios (x) in isomolar series of the two extractants were 0, 0.25, 0.5, 0.75, and 1. The sorbents were used for investigating Eu capture from 0.I and 1M HNO 3 solutions under static s-9 s conditions (24 hours shaking, 2 cm 3 aqueous phase with 0.2 g orbent, Eu initial concentrations 3.10 ,0.0001, 0.001, 0.01 and 0.1M). The orbents containing mixtures of extractants corresponding to the interpolale.A value x = 0.45 (phosphororg./dicarb.) exhibited the highest values of the distribution ratios of Eu. A synergic effect of three orders of magnitude for low concentrations of Eu was observed. A tentative determination is given of the nature and the equilibrium constants of the chemical reactions assumed.
Journal of Environmental Chemical Engineering, 2018
New titanium phosphates were synthesized and tested as potential sorbents of europium from aqueous solutions. The experiments were undertaken in the concentration region 50-2000 mg. L-1 at pH 5 without and with background electrolyte. The uptake data were determined by γ-spectroscopy with 152 Eu as tracer and fitted by the Langmuir, Freundlich and Temkin models. The new materials showed high sorption capacities (up to 259.6 mg. g-1) as derived from the Langmuir equation. Investigation of the sorption kinetics took place at 293, 303, 313 and 323 K. It was demonstrated that Eu-sorption proceeds very fast and described by pseudo-second-order kinetics while the rate constant and activation energy were calculated. Infrared and Raman spectroscopy, scanning electron microscopy and X-ray diffraction were applied for the sorbents characterization. Leaching tests were performed to assess the environmental compatibility of the loaded sorbent as well as desorption tests. The obtained data indicated that the interaction of the synthesized titanium phosphates with the Eusolutions is a complex phenomenon based on ion exchange and formation of inner-sphere complexes.
Magnesium-cadmium hydroxyapatite [(Mg-Cd)HAP] and novel multi-wall carbon nanotubes Mg-Cd hydroxyapatite (CNTs/(Mg-Cd)HAP) composites were synthesized by a co-precipitation method. The synthesized sorbents were characterized using BET surface area measurements, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). They have possessed specifi c surface area of 34.85 and 60.41 m 2 g-1 for (Mg-Cd)HAP and CNTs/(Mg-Cd)HAP, respectively. Furthermore, the synthesized sorbents were applied in removal of Eu(III) ions from aqueous solutions. Sorption performance of the synthesized sorbents towards Eu(III) ions was studied under different sorption parameters such as equilibration time, sample mass, solution pH and ionic strength. Sorption of europium reached equilibrium within 6 h at pH 2.5. The maximum sorption capacity (Q max) was 137.31 and 151.47 mg g-1 for sorption of Eu(III) onto (Mg-Cd)HAP and CNTs/(Mg-Cd) HAP, respectively. Kinetically, the sorption process followed the pseudo-second-order model and both fi lm and pore diffusions participated in ruling the diffusion of Eu(III) ions. Equilibrium sorption data of Eu(III) were analyzed using Freundlich and Langmuir isotherm models. The thermodynamic parameters (ΔG°, ΔH°, and ΔS°) for sorption of Eu(III) onto the synthesized sorbents were determined and the reaction is found to be feasible, spontaneous and endothermic process.
A new sorbent for europium nitrate extraction: phosphonic acid grafted on polystyrene resin
Journal of Radioanalytical and Nuclear Chemistry, 2011
A new chelating polymeric sorbent has been developed using polystyrene resin grafted with phosphonic acid. After characterization by FTIR and elementary analysis, the new resin has been investigated in liquid-solid extraction of europium(III). The results indicated that phosphonic resin could adsorb Eu(III) ion effectively from aqueous solution. The adsorption was strongly dependent on pH of the medium with enhanced adsorption as the pH value of 6.5. The influence of other analytical parameters including contact time, amount of resin, metal ion concentration, and ionic strength were investigated. The maximum uptake capacity of Eu(III) ions was 122.6 mg/g grafted resin at ambient temperature, at an initial pH value of 6.50. The overall adsorption process was best described by pseudo first-order kinetic. When Freundlich and Langmuir isotherms were tested, the latter had a better fit with the experimental data. Furthermore, Eu(III) could be eluted by using 1.0 mol/L H 2 SO 4 solution and the grafted resin could be regenerated and reused.
Russian Journal of Applied Chemistry, 2018
Magnesium-cadmium hydroxyapatite [(Mg-Cd)HAP] and novel multi-wall carbon nanotubes Mg-Cd hydroxyapatite (CNTs/(Mg-Cd)HAP) composites were synthesized by a co-precipitation method. The synthesized sorbents were characterized using BET surface area measurements, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). They have possessed specifi c surface area of 34.85 and 60.41 m 2 g-1 for (Mg-Cd)HAP and CNTs/(Mg-Cd)HAP, respectively. Furthermore, the synthesized sorbents were applied in removal of Eu(III) ions from aqueous solutions. Sorption performance of the synthesized sorbents towards Eu(III) ions was studied under different sorption parameters such as equilibration time, sample mass, solution pH and ionic strength. Sorption of europium reached equilibrium within 6 h at pH 2.5. The maximum sorption capacity (Q max) was 137.31 and 151.47 mg g-1 for sorption of Eu(III) onto (Mg-Cd)HAP and CNTs/(Mg-Cd) HAP, respectively. Kinetically, the sorption process followed the pseudo-second-order model and both fi lm and pore diffusions participated in ruling the diffusion of Eu(III) ions. Equilibrium sorption data of Eu(III) were analyzed using Freundlich and Langmuir isotherm models. The thermodynamic parameters (ΔG°, ΔH°, and ΔS°) for sorption of Eu(III) onto the synthesized sorbents were determined and the reaction is found to be feasible, spontaneous and endothermic process.
Materials
The research is aimed at checking the impact of a remote interaction phenomenon on growth of sorption properties of ion-exchange resins during sorption of europium ions. Industrial ion exchangers Amberlite IR120 and AB-17-8 were selected as objects for the study. Investigation was undertaken using the following physico-chemical methods of analysis: conductometry, pH-metry, colorimetry, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and atomic emission spectroscopy. Remote interaction of the initial ion exchangers in the interpolymer system leads to their transition into highly ionized state due to formation of optimal conformation. Found that high ionization areas of Amberlite IR120 and AB-17-8 are the molar ratios Amberlite IR120:AB-17-8 = 4:2 and 1:5. The remote interaction effect provides significant increase of the following sorption properties: sorption degree, polymer chain binding degree, effective dynamic exchange capacity. A strong increas...
Europium removal with a mineral mixtre
Journal of Radioanalytical and Nuclear Chemistry, 1992
Natural mixture containing mostly minerals of iron, sillicon, magnesium, aluminium and calcium was exploited for the decontamination study of europium radionuclides from aqueous radioactive waste solutions. The physicochemical conditions, such as shaking and equilibration time, nature of hydrogen ions, pH, temperature, concentrations of adsorbate and adsorbent were experimentally determined. This study showed quantitative adsorption beyond pH 7 and under optimized conditions, up to 33 g of the adsorbate can be rapidly removed from radioactive effluents using only 1 kg of the mineral mixture (MM). Desorption study of the solidified radioactive waste product reveals no significant loss (< 0.01% month), indicating MM as an effective material for removal of radioactive europium and storing it in solid form over a long period of time.
Sorption of europium on TiO2 and cement at high Ph in the presence of organic ligands
Journal of Radioanalytical and Nuclear Chemistry, 2006
Organic substances present in radioactive waste lower the sorption of metal ions at the high pH in cement matrices and, hence, enhance their possible migration. The aim of this study was to develop a method to compare organic substances or their degradation products with respect to what extent they affect metal sorption. Batch sorption studies were performed with cement or TiO 2 as solid phase and Eu(III) as a model element for trivalent lanthanides and actinides at pH 12.5 (representative of a cement waste matrix during the first approximately 100,000 years). Different kinds of ligands were studied in a broad concentration range, e.g., organic acids, cement additives, cleaning agents and degradation products from ion-exchange resin.