DOCSLIB.ORG

Silver Decorated Ceo2 Nanoparticles for Rapid Photocatalytic Degradation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Silver Decorated Ceo2 Nanoparticles for Rapid Photocatalytic Degradation www.nature.com/scientificreports OPEN Silver decorated CeO2 nanoparticles for rapid photocatalytic degradation of textile rose bengal dye G. Murugadoss1*, D. Dinesh Kumar1, M. Rajesh Kumar2*, N. Venkatesh3 & P. Sakthivel3 High quality silver (Ag) decorated CeO2 nanoparticles were prepared by a facile one-step chemical method. The samples were characterized by X-ray difraction (XRD), scanning electron microscopy (SEM), High resolution transmission electron microscopy (HR-TEM), fourier transform infrared spectrometer (FT-IR), electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), UV–Visible absorption (UV–Vis), photoluminescence (PL) and thermogravimetric analysis. The decoration of Ag on CeO2 surface was confrmed by XRD, EPR and HR-TEM analysis. Harmful textile pollutant Rose Bengal dye was degraded under sunlight using the novel Ag decorated CeO2 catalyst. It was found that great enhancement of the degradation efciency for Ag/CeO2 compared to pure CeO2, it can be ascribed mainly due to decrease in its band gap and charge carrier recombination rate. The Ag/CeO2 sample exhibited an efcient photocatalytic characteristic for degrading RB under visible light irradiation with a high degradation rate of 96% after 3 h. With the help of various characterizations, a possible degradation mechanism has been proposed which shows the efect of generation of oxygen vacancies owing to the decoration of Ag on the CeO2 surface. Metal oxide nanoparticles have been considered in more consideration due its attractive applications including energy conversion, storage, solar fuel, photocatalytic and medical. Particularly, these metal oxides have been successfully used for wastewater management and water splitting. Tey have additionally been used for a wide scope of chemical redox reactions, for example, the mineralization of natural contaminations in wastewater 1,2. Te preparation of semiconductor metal oxide nanoparticles with diferent shapes and sizes has been of interest 3,4 for application in cutting edge oxidation procedures . Various transition metal oxides such as TiO2, NiO, CuO, ZnO and BiVO4 have been have been widely examined as photocatalysts for photocatalytic hydrogen produc- tion and color removal from the textile wastewater5–10. Apart from the transition metal oxides, rare earth oxides have been paid more attention due to its interesting electronic, optical and catalytic properties. As one of the most signifcant earth oxides, ceria (CeO2) has fascinated in more consideration for its promising application in photocatalytic dye degradation, solid oxide fuel cells, electrochemical sensor, ultraviolet flter, supercapacitor, 11,12 solar cells and optical materials . CeO2 is a n-type semiconductor metal oxide, it has a few properties like 13–17 TiO2, for example, chemical inactivity, cheap, photo stability and non-toxicity . For the past one decade, color removal of organic textile dyes using suitable catalyst is an emerging target for wastewater management 18–20. Besides, rose bengal (RB) dyes are widely used in textile, plastic, printing and cosmetic industries. But RB dyes are highly soluble in water, which commonly pollutes water and highly toxic to the living organisms21,22. Terefore, it is highly essential the removal of toxic dye from water. Photocatalyst is one of a most common cost-efective method for decompose textile-dyes from water using efcient nanocatalyst. To improve creation of active species in CeO2, various modifcations were made. Among the modifcations, incorporation or decoration of metal ions like silver (Ag) is an attractive method which enhanced the optical and catalytic properties of metal oxides. Such enhancement of photocatalytic behavior was obtained because of several factors such as tuning size, improved surface to volume ratio, morphology, band gap and various types 23 24 of defects . Dawoud et al. observed that Ag doped ZrO2 nanoparticles are efectively degraded the RB dye in visible light irradiation because of the surface area, band gap and porosity. Similar degradation efect has been 1Centre for Nanoscience and Nanotechnology, Sathyabama Institute of Science and Technology, Chennai, Tamil Nadu 600119, India. 2Institute of Natural Science and Mathematics, Ural Federal University, Yekaterinburg 620002, Russia. 3Department of Nanoscience and Technology, Bharathiar University, Coimbatore, Tamil Nadu 641046, India. *email: [email protected]; [email protected] Scientifc Reports | (2021) 11:1080 | https://doi.org/10.1038/s41598-020-79993-6 1 Vol.:(0123456789) www.nature.com/scientificreports/ observed by Ziashahbi et al.25 using Ag decorated ZnO hybrid nanostructures against methylene blue under visible light. In this study, pure and Ag decorated CeO2 nanoparticles have been synthesized and characterized using experimental techniques. Crystallography, microstructure, optical and magnetic properties of the nanoparticles were systematically analysed. Photocatalytic behaviour of the pure CeO 2 and Ag decorated CeO 2 nanoparticles were evaluated by photodegradation of RB dye under visible-light irradiation. Materials and methods Synthesis of pure CeO2 and Ag decorated CeO2 nanoparticles. All chemicals were used without further purifcation with analytical grade reagent. To synthesis of Ag doped CeO2 nanoparticles, 4.3 g (0.2 M) of Ce (NO3)3·6H2O in 50 mL of deionized water and 50 ml of 0.5 g polyvinylpyrrolidone (PVP; MW:40,000) were mixed under stirring at 80 °C. Ten, 1 M of sodium hydroxide (NaOH) was added drop by drop into the above solution. Afer 1 h, 0.2 M of 1.7 g Ag(NO3) in 50 mL deionized water was added into the above solution. Subse- quently, that the white color solution was transformed into dark brown color solution indicates the decoration of Ag on the surface CeO2 nanoparticles. Afer 2 h stirring, the obtained brown color colloidal was purifed by washing with deionized water and acetone with several times to remove impurities. Te resultant powder sam- ples were dried in an oven at 120 °C for 4 h. Following the same procedure, pure CeO 2 nanoparticles was synthe- sized without adding the silver nitrate. Te growth mechanism of Ag decorated CeO 2 is demonstrated in Fig. 1a. Characterization. Structural information of the pure and doped CeO 2 was studied by powder X-ray difrac- tion (XRD) pattern using Rigaku miniFlex IIC difractometer with Cu Kα radiation (λ = 1.54060 Å). Morphol- ogy of the powder samples and microstructural information were performed using scanning electron micros- copy (SEM, TESCAN, VEGASEM) and HR‒TEM (JEOL 3010) microscopy. Functional groups of molecules presented in the surface of the samples were investigated by FT-IR using an AVATOR 360 spectrometer. Chemi- cal state of the compounds studied using X-ray photoelectron spectroscopy with an Omicron Nanotechnology Te chemical state in the nanocomposites was investigated by X-ray photoelectron spectrometer (XPS) using an ESCA + Omicron XPS system with a Mg-Kα source and photon energy of 1486.7 eV. Free radical informa- tion of the samples was studied by Electron paramagnetic spectroscopy (EPR) using Bruker EMX Plus Electron spectrometer. Optical properties of the samples were investigated using Varian Carry 5000 scan UV–Vis double beam spectrometer. Termal stability and phase transition of the sample was evaluated by thermogravimetric and diferential thermal analysis (TG–DTA) using DST Q600 20 thermometer with heating rate of 10°/min. Photocatalytic study. Photodegradation of rose bengal dye was studied using pure CeO2 and Ag deco- rated CeO2 nanoparticles in aqueous medium under sun light. For the photocatalytic reaction, 20 mg of pho- tocatalyst was dispersed into 50 mL rose bengal dye solution, the concentration of dye was used as 0.2 g/L. Te resultant solution was stirred in dark place for 1 h before the light irradiation. Ten the solution was irradiated for 3 h under sun light. To evaluate degradation performance, the irradiated solution takes out in certain time interval and it was centrifuged at 4000 rpm for 20 min. Finally, the degradation efciency of the reacted solution was determined using UV–Vis absorption spectroscopy. Te degradation study was performed under 1180 watts per square meter light intensity. Te light intensity was measured using the fux meter. Results and discussion Structural properties of CeO2 and Ag-CeO2 nanoparticles. Te XRD patterns of pure and Ag deco- rated CeO2 nanoparticles are shown in Fig. 1b. Te pure nanoparticles show well–defned cubic structure of CeO2 (Fig. 1b) with the characteristic plane of (1 1 1) orientation. Te obtained result is well matched with standard JCPDS data (fle no. 34-0394). In the case of Ag incorporated CeO2 nanoparticles, crystalline Ag peaks are obtained along CeO2 peaks with the primary characteristic of Ag (1 1 1) plane. Te attained Ag peaks are well matched with cubic structure of Ag (JCPDS fle no. 87-0717). Moreover, there is no obvious peak shifs observed in CeO2 pattern by addition of Ag which reveals that Ag is presented on surface rather occupied in the interstitial or vacancy sites of CeO 2. Te estimated average crystallite size of pure CeO 2 nanoparticle is 8.1 ± 1 nm and the size decreased to 6.5 ± 1 nm for the Ag incorporated CeO 2 nanoparticles. Te decrease in crystallite size is clearly evident from the peak broadening as shown in Fig. 1b. Besides the size of Ag crystallites found to be ~ 7.9 nm. Te obtained predominant Ag peaks are revealed that equally distributed on the CeO2 surface. Moreover, it can be noticed that the calculated lattice parameter (~ 5.414 Å) of as-synthesized CeO2 nanoparticle is slightly higher than that of bulk CeO2 (~ 5.411 Å). For Ag incorporated samples, a higher value of CeO2 lattice parameter (~ 5.553 Å) is obtained which may be due to higher surface defects and decreasing crystallite size. Microstructural analysis of pure and Ag incorporated CeO2 nanoparticles. Microstructural characteristics of pure and Ag decorated CeO2 nanoparticles are examined using SEM technique with diferent magnifcations and the results are presented in Fig. 2a–d. It can be clearly seen that the obtained particle sizes are obviously in nanoscale range with agglomeration.
Load more

Recommended publications
  • Promotion Effects and Mechanism of Alkali Metals and Alkaline Earth
    Subscriber access provided by RES CENTER OF ECO ENVIR SCI Article Promotion Effects and Mechanism of Alkali Metals and Alkaline Earth Metals on Cobalt#Cerium Composite Oxide Catalysts for N2O Decomposition Li Xue, Hong He, Chang Liu, Changbin Zhang, and Bo Zhang Environ. Sci. Technol., 2009, 43 (3), 890-895 • DOI: 10.1021/es801867y • Publication Date (Web): 05 January 2009 Downloaded from http://pubs.acs.org on January 31, 2009 More About This Article Additional resources and features associated with this article are available within the HTML version: • Supporting Information • Access to high resolution figures • Links to articles and content related to this article • Copyright permission to reproduce figures and/or text from this article Environmental Science & Technology is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Environ. Sci. Technol. 2009, 43, 890–895 Promotion Effects and Mechanism such as Fe-ZSM-5 are more active in the selective catalytic reduction (SCR) of N2O by hydrocarbons than in the - ° of Alkali Metals and Alkaline Earth decomposition of N2O in a temperature range of 300 400 C (3). In recent years, it has been found that various mixed Metals on Cobalt-Cerium oxide catalysts, such as calcined hydrotalcite and spinel oxide, showed relatively high activities. Composite Oxide Catalysts for N2O One of the most active oxide catalysts is a mixed oxide containing cobalt spinel. Calcined hydrotalcites containing Decomposition cobalt, such as Co-Al-HT (9-12) and Co-Rh-Al-HT (9, 11), have been reported to be very efficient for the decomposition 2+ LI XUE, HONG HE,* CHANG LIU, of N2O.
    [Show full text]
  • Indium, Caesium Or Cerium Compounds for Treatment of Cerebral Disorders
    Europaisches Patentamt 298 644 J European Patent Office Oy Publication number: 0 A3 Office europeen des brevets EUROPEAN PATENT APPLICATION © Application number: 88305895.0 © intci.s A61K 31/20, A61K 31/28, A61K 33/24 @ Date of filing: 29.06.88 © Priority: 07.07.87 GB 8715914 © Applicant: EFAMOL HOLDINGS PLC Efamol House Woodbridge Meadows © Date of publication of application: Guildford Surrey GU1 1BA(GB) 11.01.89 Bulletin 89/02 @ Inventor: Horrobin, David Frederick © Designated Contracting States: c/o Efamol House Woodbridge Meadows AT BE CH DE ES FR GB GR IT LI LU NL SE Guildford Surrey GU1 1BA(GB) Inventor: Corrigan, Frank ® Date of deferred publication of the search report: c/o Argyll & Bute Hospital 14.11.90 Bulletin 90/46 Lochgilphead, Argyll PA3T 8ED Scotland(GB) © Representative: Caro, William Egerton et al J. MILLER & CO. Lincoln House 296-302 High Holborn London WC1V 7 JH(GB) © Indium, caesium or cerium compounds for treatment of cerebral disorders. © A method of treatment of schizophrenia or other chronic cerebral disorder in which cerebral atrophy is shown, is characterised in that one or more as- similable or pharmaceutically acceptable indium caesium or cerium compounds is associated with a pharmaceutically acceptable diluent or carrier. CO < CD 00 O> Xerox Copy Centre PARTIAL EUROPEAN SEARCH REPORT Application number European Patent J which under Rule 45 of the European Patent Convention Office shall be considered, for the purposes of subsequent EP 88 30 5895 proceedings, as the European search report DOCUMENTS CONSIDERED TO BE RELEVANT Citation of document with indication, where appropriate, Relevant CLASSIFICATION OF THE ategory of relevant passages to claim APPLICATION (Int.
    [Show full text]
  • Atomic Weights of the Elements 1995
    Atomic Weights of the Elements 1995 Cite as: Journal of Physical and Chemical Reference Data 26, 1239 (1997); https:// doi.org/10.1063/1.556001 Submitted: 02 May 1997 . Published Online: 15 October 2009 T. B. Coplen ARTICLES YOU MAY BE INTERESTED IN Atomic Weights of the Elements 1999 Journal of Physical and Chemical Reference Data 30, 701 (2001); https:// doi.org/10.1063/1.1395055 Journal of Physical and Chemical Reference Data 26, 1239 (1997); https://doi.org/10.1063/1.556001 26, 1239 © 1997 American Institute of Physics and American Chemical Society. Atomic Weights of the Elements 1995a) T. B. Coplen U. S. Geological Survey, Reston, Virginia 20192 Received May 2, 1997; revised manuscript received June 13, 1997 The biennial review of atomic weight, Ar~E!, determinations and other cognate data has resulted in changes for the standard atomic weight of 21 elements. The five most significant changes are: boron from 10.81160.005 to 10.81160.007; carbon from 12.01160.001 to 12.010760.0008; arsenic from 74.9215960.00002 to 74.9216060.00002; cerium from 140.11560.004 to 140.11660.001; and platinum 195.0860.03 to 195.07860.002. An annotation for potassium has been changed in the Table of Standard Atomic Weights. To eliminate possible confusion in the reporting of relative lithium isotope-ratio data, the Commission recommends that such data be ex- pressed using 7Li/6Li ratios and that reporting using 6Li/7Li ratios be discontinued. Be- cause relative isotope-ratio data for sulfur are commonly being expressed on noncorre- sponding scales, the Commission recommends that such isotopic data be expressed relative to VCDT ~Vienna Can˜on Diablo Troilite! on a scale such that 34S/32S of IAEA- S-1 silver sulfide is 0.9997 times that of VCDT.
    [Show full text]
  • Uptake of Nanoparticles of Cerium Oxide and Yttrium Oxide by Acanthamoeba Castellanii (Protozoa) and Daphnia Magna (Crustacea) James R
    Virginia Journal of Science Volume 62, 1 & 2 Spring 2011 Uptake of Nanoparticles of Cerium Oxide and Yttrium Oxide by Acanthamoeba castellanii (Protozoa) and Daphnia magna (Crustacea) James R. Palmieri1, Geneva Gehring, Catherine Minichino, and Shaadi F. Elswaifi Department of Microbiology, Infectious, and Emerging Diseases, Edward Via College of Osteopathic Medicine, 2265 Kraft Drive, Blacksburg, Virginia, USA 24060 ABSTRACT Currently, nanoparticles are synthesized and used at an unprecedented rate for industrial, medical, and research applications. The use of cerium oxide nanoparticles (CeONP) and yttrium oxide nanoparticles (YtONP) results in their spread as contaminants into the environment. Once in the environment, CeONP and YtONP can be taken up by organisms in the food chain where they may pose a public health risk. In this study we determine whether Acanthamoeba castellanii and Daphnia magna uptake CeONP or YtONP from their environment and thereby play a role in the transmission of the nanoparticles. Using electron microscopy, organisms exposed to the nanoparticles were examined. Our results indicate that the nanoparticles are associated with cell and organelle membranes. These findings have implications for the health risks associated with environmental contamination by CeONP and YtONP. INTRODUCTION In this study we determine whether protists and crustaceans play a role in the transfer of cerium oxide nanoparticles (CeONP) and yttrium oxide nanoparticles (YtONP) from the environment to other organisms within the aquatic food chain. Acanthamoeba castellanii, a common protist, and Daphnia magna, a planktonic crustacean, are important components in many aquatic ecosystems. Because acanthamoebae, such as A. castellanni, are aggressive feeders they consume inorganic and organic compounds from their environment, thereby serving as a link by transferring normally unavailable inorganic components to the food chain (Weekers et al.
    [Show full text]
  • Corrosion Protection Mechanisms of Rare-Earth Compounds Based on Cerium and Praseodymium (WP-1618) Objective
    Corrosion Protection Mechanisms of Rare-Earth Compounds Based on Cerium and Praseodymium (WP-1618) Objective Hexavalent chromium containing coatings are widely used to protect U.S. military weapons systems from corrosion, yet present acute health and environmental hazards. This project focused on determining corrosion protection mechanisms for coatings that utilize rare-earth (RE) compounds instead of hexavalent chromium. Understanding the mechanisms by which RE compounds inhibit corrosion would reduce the risk of implementing environmentally friendly coating systems as chromate replacements. Technical Approach Two specific coating systems were examined; cerium-based conversion coatings (CeCCs) and epoxy polyamide primers containing praseodymium-based inhibitors. Prior to the start of the project, both coating systems had demonstrated corrosion protection that could meet current U.S. military requirements for aircraft. The approach taken in this project assumed that RE compounds are not inherently protective. Instead, the appropriate phase of a RE compound has to be incorporated into the proper type of coating to provide corrosion protection in specific environments. As part of the project, mechanistic models for corrosion protection were devised by fully characterizing the phases that were present in as-deposited coatings, the transport processes that occurred during corrosive attack, and the species that formed to passivate the substrates. Results Discovery of sub-surface crevices in substrates with CeCCs led to a significant change
    [Show full text]
  • Interactions of Lanthanides and Liquid Alkali Metals for “Liquid-Like” Lanthanide Transport in U-Zr Fuel
    Interactions of Lanthanides and Liquid Alkali Metals for “Liquid-Like” Lanthanide Transport in U-Zr Fuel THESIS Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University By Jeremy Payton Isler Graduate Program in Nuclear Engineering The Ohio State University 2017 Master's Examination Committee: Dr. Jinsuo Zhang, Advisor Dr. Marat Khafizov, Co-Advisor Copyrighted by Jeremy Payton Isler 2017 Abstract One of the major limitations in achieving increased burnup in metallic U-Zr nuclear fuel is Fuel-Cladding Chemical Interaction (FCCI). The migration of the fission product lanthanides from within the fuel to the peripheral is one of the major contributors to FCCI. A “liquid-like” transport mechanism proposes the lanthanide transport is aided by liquid cesium and liquid sodium in the pores of the fuel and at the fuel peripheral. The purpose of this thesis was to provide additional experimental evidence towards this proposed mechanism. This thesis investigated the interaction between the lanthanides and cesium and sodium, with a focus on the solubility of the lanthanides in these liquid alkali metals. First, a prediction of the solubility was calculated using the Miedema model. This prediction was then compared to the inversion crucible solubility experiment performed in this thesis. The solubility experiment studied the temperature and liquid-composition dependence of the lanthanides in liquid sodium, cesium and sodium-cesium mixtures. In addition, the solubility in mixtures shows the various alkali metals concentration effect on the solubility. With the results of differential scanning calorimetry (DSC) experiments, updated phase diagrams for sodium-neodymium and cesium-neodymium were obtained from the experimental data in this thesis.
    [Show full text]
  • Roles of Lanthanum and Cerium in Grain Refinement of Steels During
    metals Review Roles of Lanthanum and Cerium in Grain Refinement of Steels during Solidification Yunping Ji 1,2, Ming-Xing Zhang 3 and Huiping Ren 1,2,* 1 School of Material and Metallurgy, Inner Mongolia University of Science and Technology, Baotou 014010, China; [email protected] 2 School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China 3 School of Mechanical and Mining Engineering, The University of Queensland, Brisbane, QLD 4072, Australia; [email protected] * Correspondence: [email protected]; Tel.: +86-472-595-2289; Fax: +86-472-595-4368 Received: 15 October 2018; Accepted: 25 October 2018; Published: 30 October 2018 Abstract: Refinement of as-cast structures is one of the most effective approaches to improve mechanical properties, formability, and surface quality of steel castings and ingots. In the past few decades, addition of rare earths (REs), lanthanum and cerium in particular, has been considered as a practical and effective method to refine the as-cast steels. However, previous reports contained inconsistent, sometime even contradictory, results. This review summaries the major published results on investigation of the roles of lanthanum or/and cerium in various steels, provides reviews on the similarity and difference of previous studies, and clarifies the inconsistent results. The proposed mechanisms of grain refinement by the addition of lanthanum or/and cerium are also reviewed. It is concluded that the grain refinement of steels by RE additions is attributed to either heterogeneous nucleation on the in-situ formed RE inclusions, a solute effect, or the combined effect of both. The models/theories for evaluation of heterogeneous nucleation potency and for solute effect on grain refinement of cast metals are also briefly summarized.
    [Show full text]
  • Three Related Topics on the Periodic Tables of Elements
    Three related topics on the periodic tables of elements Yoshiteru Maeno*, Kouichi Hagino, and Takehiko Ishiguro Department oｆ physics, Kyoto University, Kyoto 606-8502, Japan * [email protected] (The Foundations of Chemistry: received 30 May 2020; accepted 31 July 2020) Abstaract: A large variety of periodic tables of the chemical elements have been proposed. It was Mendeleev who proposed a periodic table based on the extensive periodic law and predicted a number of unknown elements at that time. The periodic table currently used worldwide is of a long form pioneered by Werner in 1905. As the first topic, we describe the work of Pfeiffer (1920), who refined Werner’s work and rearranged the rare-earth elements in a separate table below the main table for convenience. Today’s widely used periodic table essentially inherits Pfeiffer’s arrangements. Although long-form tables more precisely represent electron orbitals around a nucleus, they lose some of the features of Mendeleev’s short-form table to express similarities of chemical properties of elements when forming compounds. As the second topic, we compare various three-dimensional helical periodic tables that resolve some of the shortcomings of the long-form periodic tables in this respect. In particular, we explain how the 3D periodic table “Elementouch” (Maeno 2001), which combines the s- and p-blocks into one tube, can recover features of Mendeleev’s periodic law. Finally we introduce a topic on the recently proposed nuclear periodic table based on the proton magic numbers (Hagino and Maeno 2020). Here, the nuclear shell structure leads to a new arrangement of the elements with the proton magic-number nuclei treated like noble-gas atoms.
    [Show full text]
  • Direct Comparison of Covalency in Thorium(IV)- and Cerium(IV)-Imido Complexes † § † § † ‡ § † Thibault Cheisson, , Kyle D
    Communication Cite This: J. Am. Chem. Soc. XXXX, XXX, XXX−XXX pubs.acs.org/JACS Multiple Bonding in Lanthanides and Actinides: Direct Comparison of Covalency in Thorium(IV)- and Cerium(IV)-Imido Complexes † § † § † ‡ § † Thibault Cheisson, , Kyle D. Kersey, , Nolwenn Mahieu, , , Alex McSkimming, † † † Michael R. Gau, Patrick J. Carroll, and Eric J. Schelter*, † P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States ‡ Departement́ de Chimie, ENS Paris-Saclay, UniversitéParis-Saclay, 94235 Cachan, France *S Supporting Information generate the anilide complex [Th(NHArF)(TriNOx)] (3)by ABSTRACT: A series of thorium(IV)-imido complexes fl F protonolysis with 3,5-bis(tri uoromethyl)aniline (Ar NH2, was synthesized and characterized. Extensive experimental Scheme 1). and computational comparisons with the isostructural cerium(IV)-imido complexes revealed a notably more Scheme 1. Syntheses of the new Th(IV)-Imido Complexes covalent bonding arrangement for the CeN bond compared with the more ionic ThNbond.The thorium-imido moieties were observed to be 3 orders of magnitude more basic than their cerium congeners. More generally, these results provide unique experimental evidence for the larger covalent character of 4f05d0 Ce(IV) multiple bonds compared to its 5f06d0 Th(IV) actinide congener. hemical bonding in lanthanide and actinide compounds C pushes our understanding and description of metal− ligand interactions. Fundamental understanding of these metal−ligand bonds redefines comprehension of the elements, even 150 years after the disclosure of the periodic trends, and contributes to new applications in reactivity.1 This knowledge from https://pubs.acs.org/doi/10.1021/jacs.9b04061.
    [Show full text]
  • USE of CERIUM OXIDE (Ceo2)
    Global NEST Journal, Vol 17, No 3, pp 536-543, 2015 Copyright© 2015 Global NEST Printed in Greece. All rights reserved USE OF CERIUM OXIDE (CeO2) NANOPARTICLES FOR THE ADSORPTION OF DISSOLVED CADMIUM (II), LEAD (II) AND CHROMIUM (VI) AT TWO DIFFERENT pHs IN SINGLE AND MULTI-COMPONENT SYSTEMS CONTRERAS A.R.1 1Department of Chemical Engineering, Escola d’Enginyeria CASALS E.2 Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain PUNTES V.2,3 2Institut Català de Nanotecnologia KOMILIS D.1 Campus de la Universitat Autònoma de Barcelona SÁNCHEZ A.1,*, 08193 Bellaterra, Spain FONT X.1 3Institut Català de Recerca i Estudis Avançats Passeig Lluís Companys, 23, 08010 Barcelona, Spain Received: 16/05/2015 Accepted: 17/05/2015 *to whom all correspondence should be addressed: Available online: 24/08/2015 e-mail: [email protected] ABSTRACT Cerium oxide (CeO2) nanoparticles (NPs) were used for the removal of cadmium (II), lead (II) and chromium (VI) ions in single aqueous solutions and in solutions with mixtures of the three metals. The adsorption studies were carried out at pH 5 and 7 using a systematic factorial experimental design that considered the metal concentration from 1 mg l-1 to 10 mg l-1 and NP concentration from 0.064 g l-1 to 0.640 g l-1. The highest adsorption capacity was obtained in the removal of lead (II) (128.1 mg g-1), followed by cadmium (II) (93.4 mg g-1) and finally chromium (VI) (34.4 mg g-1). Data were fitted to a polynomial function obtaining the best reduced models.
    [Show full text]
  • Periodic Table 1 Periodic Table
    Periodic table 1 Periodic table This article is about the table used in chemistry. For other uses, see Periodic table (disambiguation). The periodic table is a tabular arrangement of the chemical elements, organized on the basis of their atomic numbers (numbers of protons in the nucleus), electron configurations , and recurring chemical properties. Elements are presented in order of increasing atomic number, which is typically listed with the chemical symbol in each box. The standard form of the table consists of a grid of elements laid out in 18 columns and 7 Standard 18-column form of the periodic table. For the color legend, see section Layout, rows, with a double row of elements under the larger table. below that. The table can also be deconstructed into four rectangular blocks: the s-block to the left, the p-block to the right, the d-block in the middle, and the f-block below that. The rows of the table are called periods; the columns are called groups, with some of these having names such as halogens or noble gases. Since, by definition, a periodic table incorporates recurring trends, any such table can be used to derive relationships between the properties of the elements and predict the properties of new, yet to be discovered or synthesized, elements. As a result, a periodic table—whether in the standard form or some other variant—provides a useful framework for analyzing chemical behavior, and such tables are widely used in chemistry and other sciences. Although precursors exist, Dmitri Mendeleev is generally credited with the publication, in 1869, of the first widely recognized periodic table.
    [Show full text]
  • Separation of Radioactive Elements from Rare Earth Element-Bearing Minerals
    metals Review Separation of Radioactive Elements from Rare Earth Element-Bearing Minerals Adrián Carrillo García 1, Mohammad Latifi 1,2, Ahmadreza Amini 1 and Jamal Chaouki 1,* 1 Process Development Advanced Research Lab (PEARL), Chemical Engineering Department, Ecole Polytechnique de Montreal, C.P. 6079, Succ. Centre-ville, Montreal, QC H3C 3A7, Canada; [email protected] (A.C.G.); mohammad.latifi@polymtl.ca (M.L.); [email protected] (A.A.) 2 NeoCtech Corp., Montreal, QC H3G 2N7, Canada * Correspondence: [email protected] Received: 8 October 2020; Accepted: 13 November 2020; Published: 17 November 2020 Abstract: Rare earth elements (REE), originally found in various low-grade deposits in the form of different minerals, are associated with gangues that have similar physicochemical properties. However, the production of REE is attractive due to their numerous applications in advanced materials and new technologies. The presence of the radioactive elements, thorium and uranium, in the REE deposits, is a production challenge. Their separation is crucial to gaining a product with minimum radioactivity in the downstream processes, and to mitigate the environmental and safety issues. In the present study, different techniques for separation of the radioactive elements from REE are reviewed, including leaching, precipitation, solvent extraction, and ion chromatography. In addition, the waste management of the separated radioactive elements is discussed with a particular conclusion that such a waste stream can be
    [Show full text]