Presence Of Europium Research Articles

Efficient photocatalysis of Zn1-2xEuxDyxO nanoparticles towards the degradation of hazardous Rhodamine B dye

Industrial waste is the principal source of highly toxic organic and heavy metals. Treating such effluence is highly required to provide a clean ecosystem for living organisms. Photocatalysis is one of the most efficient, economical, and time-efficient ways for the removal of industrial wastes. In the current search, we propose to prepare a series of Zn1-2xEuxDyxO samples (x = 0.00–0.05), using the simple sol-gel auto-combustion route. The XRD results indicated a hexagonal structure for all samples. The presence of europium and dysprosium elements and their successful doping into the ZnO were proved by XRD and EDX analyses. The mean crystallite size and the values of band gap energy were altered by the Eu and Dy doping. The photocatalytic action of Zn1-2xEuxDyxO samples was assessed for Rhodamine B degradation. The experiments indicated a degradation with an efficiency of 99.1%, 95.1%, and 97.4% for Zn0.98Eu0.01Dy0.01O, Zn0.94Eu0.03Dy0.03O, and Zn0.90Eu0.051Dy0.05O samples, respectively within 90 min. The Zn0.98Eu0.01Dy0.01O sample exhibited the maximum photocatalytic efficiency with an excellent rate constant (r = 0.054 min−1) among all samples. The obtained findings demonstrated that the Eu and Dy co-doping at a specific concentration is a useful way to reach an effective photocatalytic activity of ZnO nanoparticles.

Efficient Removal of Polyvalent Metal Ions (Eu(III) and Th(IV)) from Aqueous Solutions by Polyurea-Crosslinked Alginate Aerogels.

The removal of polyvalent metal ions Eu(III) and Th(IV) from aqueous solutions using polyurea-crosslinked calcium alginate (X-alginate) aerogels has been investigated by batch-type experiments under ambient conditions and pH 3. The material presents relatively high sorption capacity for Eu(III) (550 g kg−1) and Th(IV) (211 g kg−1). The lower sorption capacity for Th(IV) compared to Eu(III) is attributed to the net charge of the dominant species in solution under the given experimental conditions, which is Eu3+ for Eu(III), and Th(OH)22+ and Th(OH)3+ for Th(IV). Generally, the sorption is an endothermic and entropy-driven process, and it follows the Langmuir isotherm model. According to the FTIR spectra, sorption occurs via formation of inner-sphere complexes between the surface functional groups and the f-metal cationic species. The presence of europium and thorium in the adsorbent material was confirmed and quantified with EDS analysis. To the best of our knowledge, this is the first report of an aerogel material used as an adsorbent for Eu(III). Compared to other materials used for the sorption of the specific ions, which are mostly carbon-based, X-alginate aerogels show by far the highest sorption capacity. Regarding Th(IV) uptake, X-alginate aerogels show the highest capacity per volume (27.9 g L−1) among the aerogels reported in the literature. Both Eu(III) and Th(IV) could be recovered from the beads by 65% and 70%, respectively. Furthermore, Th(VI) could also be quantitatively removed from wastewater, while Eu(III) could be removed by 20%. The above, along with their stability in aqueous environments, make X-alginate aerogels attractive candidates for water treatment and metal recovery applications.

Cover Feature: Bell–like [Ga5] clusters in Sr3Li5Ga5: synthesis, crystal structure and bonding analysis. (Z. Anorg. Allg. Chem. 18/2021)

This cover picture shows the unique bell-like [Ga5] cluster and its corresponding ELI-D maxima, in front of a drawing of an old school bell. First observed in the related compound Eu3Li5Ga5 these clusters are the first and only known galliumclusters to be nonconvex, which makes an investigation of the intra cluster bonding of particular interest. Initially hindered by the presence of europium, an application of the electron localizability approach (ELI-D) became possible with Sr3Li5Ga5 due to the absence of f electrons. The resulting insights into the bonding situation are described in great detail in our article 202100147.

A novel gas assay for ultra-small amounts of molecular oxygen based on the chemiluminescence of divalent europium

We have developed a novel assay O2-gas that allows selective determination of ultra-small amounts of molecular oxygen in gases, up to 0.18 ppm, which is one of the most sensitive assay reported so far. The assay operates with the registration of very bright chemiluminescence (CL) arising at the oxidation of diisobutylaluminum hydride iBu2AlH with oxygen in the presence of europium(II,III) compounds in the [Eu2+/3+-iBu2AlH-THF-O2] systems, where Eu2+/3+ = EuCl3·6H2O, Eu(fod)3, and EuBr2; Bu = C4H9. These systems showed the optimal spectral-brightness characteristics of CL for oxygen analysis, that have been established as a result of testing the effect of the nature of the ligand at the europium cation, organoaluminum compound, solvent, temperature, and other factors. The three systems have been successfully tested in the verification measurements of the oxygen concentration in artificial standard oxygen-argon mixtures. The CL response time to the introduction of O2 does not exceed 6 sec. The dependence of CL on oxygen concentration remains linear in the range from 44.68 to 0.18 ppm.

VIS-VUV spectroscopy of K5GdLi2F10:Tb, Eu and temperature activated energy transfer from terbium to europium

K5GdLi2F10 compound doped with Tb3+ and Eu3+ was synthetized. The excited states of these lanthanide ions were analyzed up to VUV range at 125,000 cm−1 (80 nm). Strong coupling between terbium and europium was found. The energy transfer processes from terbium to europium mainly depend on fast migration. The lifetime of 5D4 multiplet in the presence of europium is shorter by about 30% in comparison to singly doped terbium compounds. The character of the decay curve of the 5D4 multiplet is mono-exponential. Non-exponential character was discovered in the case of 5D1 europium multiplet in the presence of terbium. The nature of this quenching was determined to be dipole-dipole interaction with critical distance 9.96 Å. The energy transfer is temperature dependent.

Precursor technology for the production of white and color phosphors based on Al2O3:Ln (Ln=Eu3+, Tb3+ or Eu3+/Tb3+)

Al1-xLnx(OH)(HCOO)2 (Ln ​= ​Eu3+, Tb3+ or Eu3+/Tb3+) precursors were synthesized and used as starting reagents for the preparation of white and color luminescent materials. The X-ray powder diffraction data, Infrared, Raman spectra and thermal analysis of precursors are discussed in detail. Vibrational spectroscopy corroborates the X-ray diffraction results, Al1-xLnx(OH)(HCOO)2 crystallize in the monoclinic system. Thermolysis of Al1-xLnx(OH)(HCOO)2 precursors in helium atmosphere and in air at temperatures below 700°С allows one to obtain poorly crystallized Al2O3:Ln samples. The temperature required for the synthesis of γ-(Al1-xLnx)2O3 solid solutions is equal to 900°С. Complete characterization of the products of thermolysis of precursors was performed using X-ray powder diffraction, 27Al MAS NMR, optical absorption and luminescence. The presence of europium and terbium ions in the aluminum oxide leads to the stability of the γ-phase, i.e. inhibits the formation of α-Al2O3. The europium and terbium codoped Al2O3 prepared by thermolysis of precursors in helium atmosphere and in air exhibits luminescence close to white light under UV excitation. The optimal concentration of dopants, Eu3+ and Tb3+ ions, in the γ-Al2O3 hosts with white-blue emission makes it possible to improve the CIE color coordinates and obtain white luminescence.

Cover Feature: Tuneable Emission of Polyhedral Oligomeric Silsesquioxane Based Nanostructures that Self‐Assemble in the Presence of Europium(III) Ions: Reversible trans‐to‐cis Isomerization (ChemPlusChem 3/2020)

Cover Feature: Tuneable Emission of Polyhedral Oligomeric Silsesquioxane Based Nanostructures that Self‐Assemble in the Presence of Europium(III) Ions: Reversible <i>trans</i>‐to‐<i>cis</i> Isomerization (ChemPlusChem 3/2020)

Spectroscopic study of acetohydroxamic acid (AHA) hydrolysis in the presence of europium. Implications in the extraction system studies for lanthanide and actinide separation

Different implications of AHA hydrolysis affecting the extraction systems for actinide and lanthanide separation.

Interactions between europium and terbium ions and products of starch thermal decomposition: Spectroscopic and quantum chemical study

Addition of lanthanide ions to carbon nanoparticles produced from biological polymers such as starch may significantly improve luminescent characteristics of such nanoparticles. We have synthesized carbon nanoparticles from starch in the presence of europium and terbium ions and studied their dimensions and optical properties. We also did a quantum chemical calculation of possible compounds formed in a solution obtained after hydrothermal treatment of starch in the presence of europium and terbium ions. After 3 h of alkaline hydrolysis of starch at a temperature of 160 °C in the autoclave in the presence of Tb3+ and Eu3+ ions, we observed the formation of nanoparticles with varying size that have luminescent properties different from those of initial substances. Quantum chemical calculations of potential products show that a Eu complex with starch residues (1:5 ratio) is the most thermodynamically possible, and the Eu complex with levoglucosan is the least possible. The probability of europium and terbuim complexation with potential hydrocarbon ligands increases with the appearance of additional bonds that impart stability to the compounds. Of the compounds studied, the most effective donors are complexes with starch units, with the donor properties weakening as the number of links increases.

Optical and Morphological Characterization of Sonochemically Assisted Europium Doped Copper (I) Oxide Nanostructures

In the age where application of nanotechnology in our society has proven to be eminent, different routes of synthesizing nanoparticles have emerged. In this study nanoparticles of cuprous oxide (Cu2O) doped with different amounts of europium was prepared by using solution precursor route approach with the aid of ultrasonic sound. Copper sulphate and europium (III) nitrate pentahydrate was used as source for copper ions and europium ions respectively. X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR) were used to elucidate the cubic crystal structure and organic impurities present on Cu2Onanoparticles. UV-Vis spectroscopy was used to determine the absorption spectrum of the nanoparticles in the wavelength range of 400nm to 700nm. The bandgap of the undoped and doped Cu2O were found to fall between 2.1eV - 2.3eV. Scanning Electron Microscopy (SEM) coupled with energy dispersive x-ray was used to observe the dendritic and rodlike morphology and the presence of europium in the synthesized Cu2O nanoparticles. The observed effect on the absorbance of Cu2O upon adding Eu and a facile way of synthesizing Cu2O nanoparticles could bring a positive impact on the production of functional devices for optoelectronic and energy applications.

Europium(III) Catalysis for Reduction of Thionine Dye by Selenous Acid in Aqueous Sulfuric Acid Solutions: A Kinetic and Mechanistic Approach

ABSTRACTThe catalytic effect of europium(III) on the reduction of thionine dye (Th) by selenous acid has been studied by spectrophotometry in aqueous sulfuric acid solutions at a constant ionic strength of 3.0 mol dm−3 and at different temperatures (283–313 K). A first‐order dependence with respect to both [Th] and [EuIII] was obtained, whereas the orders with respect to [SeIV] and [H+] were less than unity. Variation of ionic strength and dielectric constant of the reaction media did not affect the reaction rates. Probable mechanistic schemes for thionine reductions in both the absence and presence of europium(III) catalyst were proposed. The rate laws associated with the reaction mechanisms were derived, and the reaction constants were calculated. The activation parameters of the rate constants of the slow steps of both uncatalyzed and catalyzed reactions along with thermodynamic quantities of the equilibrium constants are computed and discussed.

Physical basis of persistent luminescence: The case of europium doped Ca1−xSrxS

The physical basis of persistent luminescence in terms of the color of emission as well as the useful afterglow time is discussed for a commercial red-emitting Ca1−xSrxS:Eu phosphor. The discussion is based on the results of excitation/emission spectra and critical analysis of thermoluminescence (TL) data. The work focuses on: (i) the well known tuning of emission in Ca1−xSrxS:Eu phosphor (ii) control of intrinsic trapping parameters that decides the lifetime (τ) of charge in traps relevant to the phenomenon of persistent luminescence. XRD data is used to characterize the commercial phosphor. The emission spectra (λex = 275 nm) reveals the prominent well known broad emission (FWHM = 0.20 eV) at 1.92 eV/647 nm of Eu2+ along with weak transitions at 1.63 eV/761 nm, 1.75 eV/710 nm, 2.13 eV/581 nm and 2.56 eV/485 nm indicating presence of europium in Eu3+ state. Rigorous analysis of TL shows that non-first order TL peaks having τ300≈mins to hours are key to persistent luminescence in Ca1−xSrxS:Eu.

Electrochemical behavior of europium perovskites (Ca0.6Eu0.4MnO3) in alkaline aqueous media

In this paper, the electrochemical behavior of europium perovskites (Ca0.6Eu0.4MnO3) prepared by a gel combustion method followed by a thermal treatment performed at 1073 and 1473 K is compared with the pristine oxide CaMnO3 (T = 1073 K) obtained by the same method. The experiments were performed in alkaline aqueous media via open-circuit potential, cyclic voltammetry, chronopotentiometry, and impedance spectroscopy. The data show that the electrode roughness is inversely proportional to the oxide particle size. The chronopotentiometric curves show also that the presence of europium is advantageous due to the increase of the electrode roughness for the oxides formed at the same temperature (1073 K) or by increasing the charge per unit area for the oxide formed at 1473 K. The impedance spectra, which were obtained in the capacitive behavior domain, reflect the porous morphology of the electrode surfaces according to the theory developed by Levie. This feature is particularly evident for the electrodes with an average particle diameter of 90 and 60 nm, corresponding respectively to the oxides CaMnO3 and Ca0.6Eu0.4MnO3, both formed at 1073 K.

Different supramolecular architectures in self-assembled praseodymium(III) and europium(III) complexes with rare coordination pattern of salicylaldimine ligand

The metal-promoted one-step reaction of 5-methylsalicylaldehyde with 1,3-phenylenediamine in the presence of europium(III) or praseodymium(III) ions produces salicylaldimine complexes containing the N,N′-bis(5-methylsalicylidene)-1,3-phenylenediamine ligand (C22H20N2O2=H2L) as a result of the [2+1] Schiff base condensation. The compounds were characterized by spectroscopic data (ESI-MS, IR, 1H NMR, UV–Vis, luminescence), magnetic measurements, thermogravimetric analysis and X-ray crystallography. The crystal structures of the complexes reveal two different supramolecular architectures: a finite dimer in {[Eu2(μ-C22H20N2O2)2(C22H20N2O2)2(NO3)6]·2CH3CN} complex with a nine-coordinate distorted tricapped trigonal antiprism geometry and an infinite two-dimensional polymer in {[Pr2(μ-C22H20N2O2)4(NO3)6]∞·4CH3CN} complex with ten-coordinate distorted bicapped dodecahedron geometry. The rare cooordinated pattern of salicylaldimine is observed in these complexes in which the potentially tetradentate N2O2 Schiff base acts as undeprotonated monodentate and/or bridging ligands that use exclusively the oxygens as donor atoms with the nitrogen atoms not being involved in coordination.

Effects of Eu:Ag codoping on structural, magnetic and mechanical properties of lead tellurite glass ceramics

Structural, magnetic and mechanical properties of lead tellurite glass ceramics doped with variable amounts of Eu2O3 (0–10mol%) and codoped with fixed amounts of Ag2O (0.50mol%) or Ag metallic nanoparticles, AgNPs, (0.33mol%) have been studied. The investigation of the samples was performed by X-ray diffraction (XRD), EPR spectroscopy, magnetic susceptibility and elastic modulus measurements. XRD investigation shows that the studied samples were glass ceramics. XRD data were used to determine the nature and the quantitative ratio of the crystalline phases present in the samples. EPR spectroscopy was used to obtain information on the presence of europium and silver paramagnetic centers (Eu2+, Ag0, and Ag2+). No EPR signals assignable to these paramagnetic centers were registered. Magnetic susceptibility data show that the magnetic behavior of the studied glass ceramics is due to the europium ions present in the host matrix as Eu3+ and Eu2+ ions that show a very important clustering tendency. The fact that the paramagnetic Eu2+ ions are involved in aggregates explains why these ions were not detected by EPR in spite of the fact that Eu2+ ions are present in appreciable amounts. The level of the europium doping and the nature of the silver codopants (Ag2O or AgNPs) influence the structural, magnetic and mechanical behavior of the samples. In general, the structural effect of the codoping with Ag2O (that provides Ag+ ions capable to enter the host matrix) is more important than that of the AgNPs.

Photocatalytic activity of Eu3+-doped ZnO nanorods synthesized via microwave assisted technique

The doped ZnO nanorods as a photocatalyst with different Eu contents were prepared by microwave assisted method and they were characterized by means of X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), UV-Vis spectroscopy, surface area Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The average crystallite size and band gap energy of Eu-doped ZnO were varied with the Eu content. The XRD pattern of Eu-doped ZnO indicated hexagonal crystal structure with an average crystallite size of 25 nm. The presence of europium with trivalent state and its doping successfully into the crystal lattice of ZnO matrix were confirmed by XPS technique. The photocatalytic activity of Eu-doped ZnO nanorods was evaluated for methyl orange degradation. The photocatalytic experiments showed ∼91% degradation of methyl orange over 0.2 mol.% Eu doped ZnO sample within 3 h under UV light (365 nm).

Determination of amlodipine using terbium‐sensitized luminescence in the presence of europium(III) as a co‐luminescence reagent

A sensitive time-resolved luminescence method for the determination of amlodipine (AM) in methanol and in aqueous solution is described. The method is based on the luminescence sensitization of terbium (Tb(3+) ) by formation of a ternary complex with AM in the presence of tri-n-octylphosphine oxide (TOPO) as co-ligand, dodecylbenzenesulfate as surfactant and europium ion as a co-luminescence reagent. The signal for Tb-AM-TOPO is monitored at λex = 242 nm and λem = 550 nm. Optimum conditions for the formation of the complex in aqueous system were 0.015 m Tris (hydroxylmethyl) amino methane buffer, pH 9.0, TOPO (1.0 × 10(-4) m), Eu(3+) (2.0 × 10(-7) m), dodecylbenzenesulfate (0.14%) and 6.0 × 10(-5) m of Tb(3+) , which allows the determination of 10-50 ppb of AM with a limit of detection of 1.2 ppb. The relative standard deviations of the method range between 0.1 and 0.2% indicated excellent reproducibility of the method. The proposed method was successfully applied for the assay of AM in pharmaceutical formulations and in plasma samples. Average recoveries of 98.5 ± 0.2% and 95.2 ± 0.2% were obtained for AM in tablet and plasma samples respectively.

Beetroot-pigment-derived colorimetric sensor for detection of calcium dipicolinate in bacterial spores.

In this proof-of-concept study, we describe the use of the main red beet pigment betanin for the quantification of calcium dipicolinate in bacterial spores, including Bacillus anthracis. In the presence of europium(III) ions, betanin is converted to a water-soluble, non-luminescent orange 1∶1 complex with a stability constant of 1.4×105 L mol–1. The addition of calcium dipicolinate, largely found in bacterial spores, changes the color of the aqueous solution of [Eu(Bn)+] from orange to magenta. The limit of detection (LOD) of calcium dipicolinate is around 2.0×10–6 mol L–1 and the LOD determined for both spores, B. cereus and B. anthracis, is (1.1±0.3)×106 spores mL–1. This simple, green, fast and low cost colorimetric assay was selective for calcium dipicolinate when compared to several analogous compounds. The importance of this work relies on the potential use of betalains, raw natural pigments, as colorimetric sensors for biological applications.

Thin Films of Europium (III) Doped-TiO&lt;sub&gt;2&lt;/sub&gt; Prepared by Electrophoretic Deposition from Nanoparticulate Sols

Colloidal sol-gel is a common method used for the preparation of stable and homogeneous sols and thin films. The nanoparticulate sols can be easily deposited by EPD, which is a versatile technique for producing denser and thicker coatings than those produced by other techniques like dipping. A complete characterization of the sols, such as colloidal stability and electrophoretic mobility, which can be determined through zeta potential measurements, as well as the influence of deflocculants in the surface properties, is needed before using electrophoretic deposition. In this work, we have prepared sols of TiO2with an alkoxide:water molar ratio of 50:1 and Eu (III) doped-TiO2(2 mole % Eu (III)) using as precursors titanium (IV) isopropoxide and europium (III) acetate hydrate, respectively. The stability of the particulate sols was studied in terms of conductivity, zeta potential and viscosity evolution. Anatase stable sols, after peptization and without the use of any additive, were deposited on stainless steel substrates by electrophoretic deposition under both constant current and constant voltage conditions. Using different intensities and deposition times we have obtained thin films with different features (thicknesses and morphology) and different optical properties. The presence of europium (III) increases particle size, viscosity and peptization time and decreases the band gap of TiO2.

Chemiluminescence Determination of Balofloxacin Based on Europium (III)-Sensitized KBrO3-Na2S2O4Reaction in Micellar Medium

A novel chemiluminescence (CL) flow injection method for the determination of balofloxacin is described. The method is based on the weak CL signal arising from the reaction of <TEX>$KBrO_3$</TEX> with <TEX>$Na_2S_2O_4$</TEX> in acidic medium being significantly enhanced by balofloxacin in the presence of europium (III) ion and sodium dodecyl benzene sulfonate (SDBS). The experimental conditions that affected CL intensity were carefully optimized and the CL reaction mechanism was briefly discussed. Under the optimum conditions, the relative CL intensity was proportional to the concentration of balofloxacin in the range of <TEX>$7.0{\times}10^{-11}$</TEX> to <TEX>$3.0{\times}10^{-7}g\;mL^{-1}$</TEX>. The detection limit was <TEX>$2.7{\times}10^{-11}g\;mL^{-1}$</TEX> and the relative standard deviation was 2.1% for <TEX>$7.0{\times}10^{-10}g\;mL^{-1}$</TEX> balofloxacin (n = 13). The proposed method was successfully applied to the determination of balofloxacin in pharmaceutical formulations and biological fluids.