DOCSLIB.ORG

Quantum-Chemical Modeling of the Chemistry Process

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Quantum-Chemical Modeling of the Chemistry Process Chemistry, Technology and Application of Substances Vol. 3, No. 1, 2020 M. A. Sozanskyi, V. E. Stadnik, P. Yo. Shapoval, O. P. Kurylo, R. R. Guminilovych Lviv Polytechnic National University, Department of Physical, Analytical and General Chemistry [email protected] QUANTUM-CHEMICAL MODELING OF THE CHEMISTRY PROCESS OF THE ZINC SULFIDE AND ZINC SELENIDE FILMS SYNTHESIS https://doi.org/ The quantum-chemical modeling of the synthesis process chemistry of ZnS and ZnSe in aqueos solutions was carried out.For modeling the simulation of ZnS synthesis was made through the formation of Zn(II) complex forms with the trisodium citrate, sodium hydroxide and the pair of ammonium hydroxide with hydrazine hydrate. For the synthesis of ZnSe was used only sodium hydroxide.It was established that this process passes through several intermediate stages with the transitional reactive complexes formation. On the basis of obtained data, the energy stages diagrams are constructed and the comparison of ZnS and ZnSe synthesis processes with various complexing agents is presented.The ZnS and ZnSe filmswere obtained by chemical synthesis method from an aqueous solution of zinc salt, complexing and chalcogenizing agents. X-ray phase analysis confirmed the formation of desired compounds, as well as the formation of ZnO in the case of ammonium hydroxide – hydrazine hydrate usage at the synthesis of ZnS films. Key words: zinc sulfide, zinc selenide, thin films, quantum-chemical modeling, semiempirical methods, semiconductors. Introduction which occur between the liquid and solid phases Semi-empirical method of quantum chemistry (newly formed the reaction product and substrate) at is one of the modeling reactions methods between a short distance from the latter. molecules and substances by quantum-chemical cal- For the some metals ions (Me = Pb2+, Cu2+, culations [1–3]. In Refs. [4–6], the theoretical basis Cd2+, Hg2+), the formation of complexes with 2+ of metal sulfides films formation from aqueous thiourea of [Me((NH2)2CS)4] type was established solution were described. Among the main factors [4, 7]. From the reference data [4], the value of the affecting the course of the reaction, the following stability constant of such zinc complex is very small can be distinguished: (often absent in reference books),which does not 1. Concentration of initial reagents of the apply to the mentioned above metals. So it is logical solution from which depositionismade and the phy- to assume the formation of intermediate complexes sical parameters of the process (temperature, syn- of [Ln∙∙∙Zn∙∙∙(NH2)2CS] type, where zinc is coor- thesis duration, etc.); dinated on the one hand by ligands of the comp- 2. Nature of complexing and chalcogenizing lexing agent, and on the other by thiourea. The reagents that surround the metal ion and generate decomposition process of such intermediate comp- chalcogen ions during the synthesis, respectively; lexes, as a rule, involves the formation of molecular 3. Nature of the substrate surface on which the forms, and then monomolecular layers of zinc films are formed. chalcogenide. To reduce the formation of by-pro- It was noted [4] that during the synthesis ducts, it is necessary to create conditions in which process, the formation of transitional molecular the supply of zinc- and chalcogen-containing agents reactive complexes (TMRC), associates, cluster and will be the same. It is also worth noting that some colloidal forms were possible in the working solution complexing agents perform only one function – the due to cooperation and fluctuation phenomena, formation of a complex with metal. In this case, it is 1414 Quantum-chemical modeling of the chemistry process of the zinc sulfide and zinc selenide films synthesis necessary to add an additional pH regulator to ensure Results and discussion the stability and reactivity of the complex. Other The results of quantum chemical modeling of complexing agents are able tofulfill two functions at the ZnS and ZnSe films synthesis chemistry in the same time – to coordinate the metal ion and aqueous solutions with various complexing agents by create the required hydrogen index of the solution. semi-empirical methods are presented in table 1. The geometry of starting zinc complexes are illustratedin Aim of the work Fig. 1–3. The aims of the present study are the follo- Quantum-chemicalmodelingof ZnS synthesis wing: 1. Implementationofquantum-chemical mode- chemistry with Na3C6H5O7. ling of the ZnS and ZnSe synthesis processes Initially, when mixing solutions of zinc salt – withtheuseof PM7 method in MOPAC 2012 and trisodium citrate, a soluble [Zn(C6H5O7)] software package. This could be made on the basis of complex is formed (Fig. 1), where citrate ion plays the hypothesis about the possibility of formation of the role of a ligand. transient reactive complexes, associates, clusters, As can be seen from the conducted quantum- structures of colloidal nature, which are structural chemical modeling(table. 1, no. 1, stages 1–3) that units during the synthesis of zinc chalcogenide films after adding thiourea and a small amount of pH due to the effects of co-operation and fluctuation in regulator to the solution, the 3– the working solution. 2. Comparison of the obtained [(NH2)2CS∙∙∙Zn(OH)2(C6H5O7)] TMRC is formed results of ZnS and ZnSe simulations with the in the early stages of deposition. In the TMRC the investigated properties of respective films. 3. Feasi- Zn atom is coordinated with the S atom (Fig. 4). This bility and efficiency evaluation of the synthesis in process is accompanied by a slight endoeffect, that observed systems. is, energy absorption. Next, starting from stage 3 to stage 6, the Materials and research methods formed complex undergoes rearrangement of two Modeling and calculations of the system hydrogen atoms of (NH2)2CS with two hydroxyl energy change (ΔE) for the synthesis stages of zinc groups and detaching of two water molecules. As a 3– sulfide and zinc selenide were carried out by the result, [(N2H2СS∙∙∙Zn(C6H5O7)] TMRC is formed. semi-empirical method PM7 [8] with the use of The result of these stages is a decrease in total MOPAC 2012 software package [9] and the energy of the system. Winmostar graphical interface [10]. At the last stage, which is the most energy- The synthesis of ZnS films was carried out intensive, the newly formed intermediate complex from a working solution prepared by mixing aqueous decomposed with the formation of zinc sulfide, solutions of zinc chloride (ZnCl2), complexing agent, citrate ion and cyanamide (stages 6–7). thiourea ((NH ) CS) and, if necessary, the pH regu- 2 2 During deposition process, the citrate ion lator. Solutions of trisodium citrate (Na C H O ), 3 6 5 7 (C H O 3–) does not change its structure and sodium hydroxide (NaOH), and a pair of ammonium 6 5 7 performs only a ligand role. hydroxide (NH4OH) with hydrazine hydrate (N2H4·H2O) were used as complexing agents. The Quantum-chemicalmodelingof ZnS synthesis exact synthesis parameters of ZnS films are given in chemistry with NaOH. ref. [11]. In the case of mixing of a zinc salt solution The synthesis of ZnSe films was carried out with an excess of sodium hydroxide solution, which from a working solution prepared by mixing aqueous is a complexing agent and pH regulator at the same solutions of zinc chloride (ZnCl2), sodium hydroxide time, a soluble complex of tetratrahydroxozincate and elemental selenium (Se) dissolved therein with 2– ([Zn(OH)4] ) is formed (Fig. 2). the presence of hydrazine hydrate. The exact synthe- As can be seen from the performed modeling sis parameters of ZnS films are given in ref. [12, 13]. The X-ray diffraction patterns of deposited (table 1, no. 2, stages 1–2) that TMRC 2– ZnS and ZnSe films samples were performedwith the [(NH2)2CS∙∙∙Zn(OH)4] is formed at the beginning use of DRON-3.0 diffractometer (Cu Kα–radiation). of the deposition, after the addition of thiourea in the The primary treatment of films diffractogram for the working solution (Fig. 5). InthisTMRC, the zinc identification of phases was carried outby using atom is coordinated with the sulfur atom of the Powder Cell program [14]. thiourea, with a slight increase in system energy. 15 M. A. Sozanskyi, V. E. Stadnik, P. Yo. Shapoval, O. P. Kurylo, R. R. Guminilovych Table 1 Modeled stages of ZnS and ZnSe films synthesis and energy stages diagrams Complexing No. Film Energy stages diagrams Modeled stages agent -3000 Stages 1→3: ZnS (Na3C6H5O7) – – -3050 [Zn(C6H5O7)] + 2OH + (NH2)2CS → 3– → [(NH2)2CS∙∙∙Zn(OH)2(C6H5O7)] ; -3100 Stages 3→6: 3– 1. ZnS Na3C6H5O7 E, kJ/mol -3150 [(NH2)2CS∙∙∙Zn(OH)2(C6H5O7)] → 3– → [(N2H2СS∙∙∙∙∙Zn(C6H5O7)] + 2H2O ; -3200 Stages 6→7: 3– -3250 [(N2H2СS∙∙∙Zn(C6H5O7)] → ZnS↓ + 1 2 3 4 5 6 7 3– + C6H5O7 + CH2N2 . Stage number Stages 1→2: 2– -1550 [Zn(OH)4] + (NH2)2CS → 2– ZnS (NaOH) → [(NH2)2CS∙∙∙Zn(OH)4] ; -1600 Stages2→5: -1650 2– [(NH2)2CS∙∙∙Zn(OH)4] → 2– -1700 → [(N2H2СS∙∙ Zn(OH)2] + 2H2O ; 2. ZnS NaOH E, kJ/mol -1750 Stages5→6: [(N H СS∙∙ Zn(OH) ]2– → -1800 2 2 2 2– [S∙∙∙Zn(OH)2] + CH2N2 ; -1850 1 2 3 4 5 6 7 Stages 6→7: Stage number 2– – [S∙∙∙Zn(OH)2] → ZnS↓ + 2OH . Stages 1→2: -350 2+ – [Zn(NH3)4] + 2OH → Zn(OH)2 + ZnS (NH4OH + N2H4H2O) -400 4NH3↑; -450 Stages 2→3: Zn(OH)2 + (NH2)2CS → NH4OH + -500 3. ZnS E, kJ/mol → [(NH2)2CS∙∙∙Zn(OH)2] ; N2H4·H2O -550 Stages 3→7: -600 [(NH2)2CS∙∙∙Zn(OH)2] → -650 → ZnS↓ + CH2N2 + 2H2O ; 1 2 3 4 5 6 7 Stage number By-process: Zn(OH)2→ZnO+ H2O . -2300 ZnSe (NaOH) -2400 Stages 1→2: 2- 2- 4– [Zn(OH)4] + Se → [Se∙∙∙Zn(OH)4] ; -2500 4.
Load more

Recommended publications
  • Sodium Hydroxide
    Sodium hydroxide From Wikipedia, the free encyclopedia • Learn more about citing Wikipedia • Jump to: navigation, search Sodium hydroxide IUPAC name Sodium hydroxide Other names Lye, Caustic Soda Identifiers CAS number 1310-73-2 Properties Molecular NaOH formula Molar mass 39.9971 g/mol Appearance White solid Density 2.1 g/cm³, solid Melting point 318°C (591 K) Boiling point 1390°C (1663 K) Solubility in 111 g/100 ml water (20°C) Basicity (pKb) -2.43 Hazards MSDS External MSDS NFPA 704 0 3 1 Flash point Non-flammable. Related Compounds Related bases Ammonia, lime. Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references Sodium hydroxide (NaOH), also known as lye, caustic soda and sodium hydrate, is a caustic metallic base. Caustic soda forms a strong alkaline solution when dissolved in a solvent such as water. It is used in many industries, mostly as a strong chemical base in the manufacture of pulp and paper, textiles, drinking water, soaps and detergents and as a drain cleaner. Worldwide production in 1998 was around 45 million tonnes. Sodium hydroxide is the most used base in chemical laboratories. Pure sodium hydroxide is a white solid; available in pellets, flakes, granules and as a 50% saturated solution. It is deliquescent and readily absorbs carbon dioxide from the air, so it should be stored in an airtight container. It is very soluble in water with liberation of heat. It also dissolves in ethanol and methanol, though it exhibits lower solubility in these solvents than potassium hydroxide.
    [Show full text]
  • Structural Diversity of Anodic Zinc Oxide Controlled by the Type Of
    Reviews ChemElectroChem doi.org/10.1002/celc.202100216 Zinc Anodizing: Structural Diversity of Anodic Zinc Oxide Controlled by the Type of Electrolyte Katja Engelkemeier,*[a, c] Aijia Sun,[a, c] Dietrich Voswinkel,[b, c] Olexandr Grydin,[b, c] Mirko Schaper,[b, c] and Wolfgang Bremser[a, b] ChemElectroChem 2021, 8, 1–15 1 © 2021 The Authors. ChemElectroChem published by Wiley-VCH GmbH These are not the final page numbers! �� Wiley VCH Dienstag, 18.05.2021 2199 / 204431 [S. 1/15] 1 Reviews ChemElectroChem doi.org/10.1002/celc.202100216 Anodic zinc oxide (AZO) layers are attracting interdisciplinary The article gives an overview of the different possibilities of research interest. Chemists, physicists and materials scientists anodic treatment, whereby the voltage and the current type are are increasingly devoting attention to fundamental and the main distinguishing criteria. Presented is the electrolytic application-related research on these layers. Research work oxidation (anodizing) and the electrolytic plasma oxidation focuses on the application as semiconductor, corrosion protec- (EPO). The electrolytic etching is also a process of anodic tor, adhesion promoter, abrasion protector, or antibacterial treatment. However, it does not produce AZO layers, but rather surfaces. The structure and crystallinity essentially determine a degradation of the zinc layer. The review article shows the the properties of the AZO coatings. The type and concentration parameters used so far (electrolyte, current type, current of the electrolyte, the applied current density or voltage as well density, voltage) and points out the influence on the formation as the duration time enable layer structures of structural variety. of AZO structures in dependency to the used electrolyte.
    [Show full text]
  • Zinc Oxide and Zinc Hydroxide Formation Via Aqueous Precipitation: Effect of the Preparation Route and Lysozyme Addition
    Materials Chemistry and Physics 167 (2015) 77e87 Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys Zinc oxide and zinc hydroxide formation via aqueous precipitation: Effect of the preparation route and lysozyme addition * Ayben Top , Hayrullah Çetinkaya _ _ Department of Chemical Engineering, Izmir Institute of Technology, Urla-Izmir, 35430, Turkey highlights graphical abstract Aqueous precipitation products of Zn(NO3)2 and NaOH were prepared. Synthesis route and lysozyme addi- tion affected morphology of the products. ε-Zn(OH)2, b-Zn(OH)2, and ZnO crys- tal structures were observed. Lysozyme-ZnO/Zn(OH)2 composites with ~5e20% lysozyme content were obtained. article info abstract Article history: Aqueous precipitation products of Zn(NO3)2 and NaOH obtained by changing the method of combining Received 13 February 2015 the reactants and by using lysozyme as an additive were investigated. In the case of single addition Received in revised form method, octahedral ε-Zn(OH)2 and plate-like b-Zn(OH)2 structures formed in the absence and in the 20 August 2015 presence of lysozyme, respectively. Calcination of these Zn(OH) samples at 700 C yielded porous ZnO Accepted 10 October 2015 2 structures by conserving the template crystals. When zinc source was added dropwise into NaOH so- Available online 24 October 2015 lution, predominantly clover-like ZnO crystals were obtained independent of lysozyme addition. Mixed spherical and elongated ZnO morphology was observed when NaOH was added dropwise into Zn(NO ) Keywords: 3 2 Oxides solution containing lysozyme. Lysozyme contents of the precipitation products were estimated as in the e fi Composite materials range of ~5 20% and FTIR indicated no signi cant conformational change of lysozyme in the composite.
    [Show full text]
  • Chemical Deposition of Zinc Hydroxosulfide Thin Films from Zinc (II) - Ammonia-Thiourea Solutions B
    Chemical Deposition of Zinc Hydroxosulfide thin Films from Zinc (II) - Ammonia-Thiourea Solutions B. Mokili, M. Froment, D. Lincot To cite this version: B. Mokili, M. Froment, D. Lincot. Chemical Deposition of Zinc Hydroxosulfide thin Films from Zinc (II) - Ammonia-Thiourea Solutions. J. Phys. IV, 1995, 05 (C3), pp.C3-261-C3-266. 10.1051/jp4:1995324. jpa-00253690 HAL Id: jpa-00253690 https://hal.archives-ouvertes.fr/jpa-00253690 Submitted on 1 Jan 1995 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. JOURNAL DE PHYSIQUE lV Colloque C3, supplCment au Journal de Physique 111, Volume 5, avril 1995 Chemical Deposition of Zinc Hydroxosulfide thin Films from Zinc (11) - Ammonia-Thiourea Solutions B. Mokili, M. Froment* and D. ~incot(1) Laboratoire d'Electrochimie et de Chimie Analytique, Unite' Associke au CNRS, Ecole Nationale Supe'rieure de Chimie de Paris, I I rue Pierre et Marie Curie, 75231 Paris cedex 05, France * UPR 15 du CNRS "Physiquedes Liquides et Electrochimie", Universite' Pierre et Marie Curie, 75252 Paris cedex 05, France Abstract The growth of ZnS films from ammonia solutions using thiourea as a sulfur precursor has been investigated.
    [Show full text]
  • LESSON 11 THEME: Equilibriums in Solutions of Coordination Complexes
    LESSON 11 THEME: Equilibriums in solutions of coordination complexes. Heterogeneous equilibriums and processes. Research work: «Reception of complexes. Medicobiological value: the coordination complexes carry out various biological functions. So, for vital activity of a human organism the unique value has a coordination complex of iron ions with protein - haemoglobin exercising transport of oxygen from lung to tissues. In life of plants the important role is played chlorophyll - complex of magnesium, due to which the plants transmute carbone dioxide and water into composite organic matters (amylum, saccharum, etc.). The ion Cu2+is the component of several important enzymes - participants of a biological oxidizing. The coordination complexes of a cobalt considerably raise intensity of protein metabolism, regulate composition of a blood. Metalenzymes is the coordination complexes with high specificity of ions of metals, among them, except for mentioned above, is more often than others there are ions of zinc, molybden, manganese. In the whole cations almost of all metals are in alive organisms as coordination complexes. Pollution by transition metals and their compounds: mercury, lead, cadmium, chromium, nickel - can result into a poisoning. The toxicity of such compounds in many cases is explained to that these ions supersede ions of biogenic metals (Fe, Zn, Cu, W) from coordination complexes with a bioorganic ligand (for example, porphyrin). The stability of coordination complexes, formed at it, usually is higher, they collect in an organism, therefore the normal vital activity of an organism is broken and the toxicosis begins. The coordination complexes will be used in medical practice. Various metals (macroelements) introduce to the organism as coordination complexes.
    [Show full text]
  • Complex Ions and Amphoterism
    Chemistry 112: Reactions Involving Complex Ions Page 27 COMPLEX IONS AND AMPHOTERISM his experiment involves the separation and identification of ions using Ttwo important reaction types: (i) the formation of complex ions and (ii) the amphoteric behavior of some metal hydroxides. You have already encoun- tered complex ion formation in the analysis of the silver group ions and in the experiment on metal sulfides, but more needs to be said about this topic as an introduction to this experiment. THE FORMATION OF COMPLEX IONS Although we usually write cation formulas in solution as if they were simple ions, such as Al3+, these ions are actually bound to a number of water mol- ecules arranged around the central ion (see figure below). The water molecules in this case are examples of a much larger class of molecules and ions called ligands that form coordinate covalent bonds with a central metal cation. That is, the bond is of the form L: → Mn+, where L has donated δ+ an otherwise unused lone pair of electrons H As noted in the experiment on the to the electron accepting metal ion. In the 3+ δ+ H O Al silver group ions, a ligand is a Lewis water molecule, there are two lone pairs of •• base (a donor of one or more pairs of electrons on the O atom, and either of these δ− electrons), and the metal ion in the may form a coordinate covalent bond with a complex ion is a Lewis acid (an elec- metal cation. Ligands are often small, polar tron pair acceptor).
    [Show full text]
  • Complex Ions and Amphoterism
    Chemistry 112: Reactions Involving Complex Ions Page 27 COMPLEX IONS AND AMPHOTERISM his experiment involves the separation and identification of ions using Ttwo important reaction types: (i) the formation of complex ions and (ii) the amphoteric behavior of some metal hydroxides. You have already encoun- tered complex ion formation in the analysis of the silver group ions and in the experiment on metal sulfides, but more needs to be said about this topic as an introduction to this experiment. THE FORMATION OF COMPLEX IONS Although we usually write cation formulas in solution as if they were simple ions, such as Al3+, these ions are actually bound to a number of water mol- ecules arranged around the central ion (see figure below). The water molecules in this case are examples of a much larger class of molecules and ions called ligands that form coordinate covalent bonds with a central metal cation. That is, the bond is of the form L: → Mn+, where L has donated δ+ an otherwise unused lone pair of electrons H As noted in the experiment on the to the electron accepting metal ion. In the 3+ δ+ H O Al silver group ions, a ligand is a Lewis water molecule, there are two lone pairs of •• base (a donor of one or more pairs of electrons on the O atom, and either of these δ− electrons), and the metal ion in the may form a coordinate covalent bond with a complex ion is a Lewis acid (an elec- metal cation. Ligands are often small, polar tron pair acceptor).
    [Show full text]
  • Intercalations and Characterization of Zinc/Aluminium Layered Double Hydroxide-Cinnamic Acid
    Available online at BCREC website: https://bcrec.id Bulletin of Chemical Reaction Engineering & Catalysis, 14 (1) 2019, 165-172 Research Article Intercalations and Characterization of Zinc/Aluminium Layered Double Hydroxide-Cinnamic Acid Nurain Adam1,2, Sheikh Ahmad Izaddin Sheikh Mohd Ghazali2*, Nur Nadia Dzulkifli2, Cik Rohaida Che Hak3, Siti Halimah Sarijo1 1Faculty of Applied Sciences, Universiti Teknologi MARA, 40450, Shah Alam, Malaysia 2Faculty of Applied Sciences, Universiti Teknologi MARA, Pekan Parit Tinggi, 72000, Kuala Pilah, Negeri Sembilan, Malaysia 3Material Technology Group, Industrial Technology Division, Malaysian Nuclear Agency, Kajang, Malaysia Received: 1st October 2018; Revised: 8th December 2018; Accepted: 12nd December 2018; Available online: 25th January 2019; Published regularly: April 2019 Abstract Cinnamic acid (CA) is known to lose its definite function by forming into radicals that able to penetrate into the skin and lead to health issues. Incorporating CA into zinc/aluminum-layered double hydroxides (Zn/Al-LDH) able to reduce photodegradation and eliminate close contact between skin and CA. Co-precipitation or direct method used by using zinc nitrate hexahydrate and aluminium nitrate nonahydrate as starting precursors with addition of various concentration of CA. The pH were kept constant at 7±0.5. Fourier Transform Infrared-Attenuated Total Reflectance (FTIR-ATR) shows the presence of nanocomposites peak 3381 cm–1 for OH group, 1641 cm–1 for C=O group, 1543 cm–1 for C=C group and 1206 cm–1 for C–O group and disappearance of N–O peak at 1352 cm–1 indi- cates that cinnamic acid were intercalated in between the layered structures. Powder X-Ray Diffraction (PXRD) analysis for Zn/Al-LDH show the basal spacing of 9.0 Ǻ indicates the presence of nitrate and increases to 18.0 Ǻ in basal spacing in 0.4M Zn/Al-LDH-CA.
    [Show full text]
  • Selective Recovery of Chromium, Copper, Nickel, and Zinc from an Acid Solution Using an Environmentally Friendly Process
    Selective recovery of chromium, copper, nickel, and zinc from an acid solution using an environmentally friendly process Manuela D. Machado & Eduardo V. Soares & Helena M. V. M. Soares Abstract solution at pH 10, selective recovery of zinc (82.7% as Purpose Real electroplating effluents contain multiple zinc hydroxide) and chromium (95.4% as a solution of metals. An important point related with the feasibility of cromate) was achieved. the bioremediation process is linked with the strategy to Conclusion The approach, used in the present work, recover selectively metals. In this work, a multimetal allowed a selective and efficient recovery of chromium, solution, obtained after microwave acid digestion of the copper, nickel, and zinc from an acid solution using a ashes resulted from the incineration of Saccharomyces combined electrochemical and chemical process. The cerevisiae contaminated biomass, was used to recover strategy proposed can be used for the selective recovery selectively chromium, copper, nickel, and zinc. of metals present in an acid digestion solution, which Results The acid solution contained 3.8, 0.4, 2.8, and resulted from the incineration of ashes of biomass used in 0.2 g/L of chromium(III), copper, nickel, and zinc, the treatment of heavy metals rich industrial effluents. respectively. The strategy developed consisted of recov- ering copper (97.6%), as a metal, by electrolyzing the Keywords Chemical precipitation . Electrolysis . Heavy solution at a controlled potential. Then, the simultaneous metals . Recycling . Selective recovery. Chemical speciation alkalinization of the solution (pH 14), addition of H2O2, and heating of the solution led to a complete oxidation of chromium and nickel recovery (87.9% as a precipitate of 1 Introduction nickel hydroxide).
    [Show full text]
  • Xanthan Gum Capped Zno Microstars As a Promising Dietary Zinc Supplementation
    foods Article Xanthan Gum Capped ZnO Microstars as a Promising Dietary Zinc Supplementation Alireza Ebrahiminezhad 1,2, Fatemeh Moeeni 2, Seyedeh-Masoumeh Taghizadeh 2, Mostafa Seifan 3, Christine Bautista 3, Donya Novin 3, Younes Ghasemi 2,* and Aydin Berenjian 3,* 1 Department of Medical Nanotechnology, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz 71348, Iran; [email protected] 2 Department of Pharmaceutical Biotechnology, School of Pharmacy and Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz 71348, Iran; [email protected] (F.M.); [email protected] (S.-M.T.) 3 School of Engineering, Faculty of Sciences and Engineering, University of Waikato, Hamilton 3216, New Zealand; [email protected] (M.S.); [email protected] (C.B.); [email protected] (D.N.) * Correspondence: [email protected] (Y.G.); [email protected] (A.B.) Received: 7 February 2019; Accepted: 26 February 2019; Published: 2 March 2019 Abstract: Zinc is one of the essential trace elements, and plays an important role in human health. Severe zinc deficiency can negatively affect organs such as the epidermal, immune, central nervous, gastrointestinal, skeletal, and reproductive systems. In this study, we offered a novel biocompatible xanthan gum capped zinc oxide (ZnO) microstar as a potential dietary zinc supplementation for food fortification. Xanthan gum (XG) is a commercially important extracellular polysaccharide that is widely used in diverse fields such as the food, cosmetic, and pharmaceutical industries, due to its nontoxic and biocompatible properties. In this work, for the first time, we reported a green procedure for the synthesis of ZnO microstars using XG, as the stabilizing agent, without using any synthetic or toxic reagent.
    [Show full text]
  • A Critical Review of Synthesis Parameters Affecting the Properties
    Applied Water Science (2021) 11:48 https://doi.org/10.1007/s13201-021-01370-z REVIEW ARTICLE A critical review of synthesis parameters afecting the properties of zinc oxide nanoparticle and its application in wastewater treatment E. Y. Shaba1 · J. O. Jacob1 · J. O. Tijani1 · M. A. T. Suleiman1 Received: 5 October 2020 / Accepted: 18 January 2021 / Published online: 13 February 2021 © The Author(s) 2021 Abstract In this era, nanotechnology is gaining enormous popularity due to its ability to reduce metals, metalloids and metal oxides into their nanosize, which essentially alter their physical, chemical, and optical properties. Zinc oxide nanoparticle is one of the most important semiconductor metal oxides with diverse applications in the feld of material science. However, several factors, such as pH of the reaction mixture, calcination temperature, reaction time, stirring speed, nature of capping agents, and concentration of metal precursors, greatly afect the properties of the zinc oxide nanoparticles and their applications. This review focuses on the infuence of the synthesis parameters on the morphology, mineralogical phase, textural proper- ties, microstructures, and size of the zinc oxide nanoparticles. In addition, the review also examined the application of zinc oxides as nanoadsorbent for the removal of heavy metals from wastewater. Keywords Zinc oxide · Synthesis parameters · Nanoadsorbent · Heavy metals Introduction 2019). In each phase, zinc oxide nanoparticles (ZnONPs) are a semiconductor material with a direct wide bandgap of Zinc oxide nanoparticles constitute one of the important ∼ 3.3 eV (Senol et al. 2020). It has advantages such as sta- metal oxides materials that have been widely applied in bilization on substrate especially the zincblende form with materials science due to its unique physical, chemical, and a cubic lattice structure (Parihar et al.
    [Show full text]
  • Preparatory Problems
    Preparatory Problems 43rd International Chemistry Olympiad Editor: Saim Özkar Department of Chemistry, Middle East Technical University Tel +90 312 210 3203, Fax +90 312 210 3200 e-mail [email protected] January 2011 Ankara 2 Preparatory Problems Problem Authors O. Yavuz Ataman Sezer Aygün Metin Balcı Özdemir Doğan Jale Hacaloğlu Hüseyin İşçi Ahmet M. Önal Salih Özçubukçu İlker Özkan Saim Özkar Cihangir Tanyeli Department of Chemistry, Middle East Technical University, 06531 Ankara, Turkey. 3 Preparatory Problems Preface We have provided this set of problems with the intention of making the preparation for the 43rd International Chemistry Olympiad easier for both students and mentors. We restricted ourselves to the inclusion of only a few topics that are not usually covered in secondary schools. There are six such advanced topics in theoretical part that we expect the participants to be familiar with. These fields are listed explicitly and their application is demonstrated in the problems. In our experience each of these topics can be introduced to well-prepared students in 2-3 hours. Solutions will be sent to the head mentor of each country by e-mail on 1st of February 2011. We welcome any comments, corrections or questions about the problems via e-mail to [email protected]. Preparatory Problems with Solutions will be on the web in July 2011. We have enjoyed preparing the problems and we hope that you will also enjoy solving them. We look forward to seeing you in Ankara. Acknowledgement I thank all the authors for their time, dedication, and effort. All the authors are Professors in various fields of chemistry at Middle East Technical University.
    [Show full text]