Incorporation of Nano-Zinc Oxide in Lamellar Zirconium Phosphate: Synthesis and Characterization

In order to provide ultraviolet barrier, antifungal and antibacterial properties, nano-zinc oxide (ZnO) was added to lamellar zirconium phosphate (ZrP). The phosphate was synthesized via reaction of zirconium oxychloride octahydrate and phosphoric acid following its chemical modification with Jeffamine and nano-ZnO. Diffractometric, morphological, thermal, structural and relaxometric evaluations were conducted. Fourier transform infrared spectroscopy (FTIR) revealed increase of the area between 4000 - 3000 cm-1 due to the formation of ionic specie PO? +NH3-[C-(H)(CH3)-CH2-O-(C-(H)(CH3)-CH2-O)8-(CH2-CH2-O-CH3)] and nano-ZnO particles. Wide-angle X-ray diffraction indicated that intercalation of Jeffamine was successful. Thermogravimetry confirmed that nano-ZnO particle forced the expulsion of Jeffamine outside ZrP galleries. Scanning electron microscopy evidenced the Jeffamine intercalation and sample heterogeneity. Hydrogen molecular relaxation indicated the increase of molecular rigidity owing to the formation of ionic specie and the addition of nano-ZnO particles. It was postulated that a multifunctional and miscellaneous material constituted by as prepared ZrP, some delaminated ZrP platelets and nano-ZnO particles was achieved. The material has potential for usage as filler in polymeric composites.

Confocal Laser Scanning Microscope Evaluation of Early Bacterial Colonization on Zirconium Oxide and Titanium Surfaces:An in vivo Study

To investigate the bacterial colonization on zirconium oxide and titanium surfaces in vivo quantitatively using a confocal laser scanning microscope （CLSM）. Ten samples of zirconium oxide ceramic and commercially pure titanium were fabricated and polished using silicon carbide abrasive paper. One sample from each group was evaluated topographic pattern under a scanning electron microscope. One sample from each group was to evaluate roughness using a profilometer. Eight volunteers were selected. The samples were cemented at the buccal surfaces of upper first molars. All samples were removed after 48 hours, immersed in SYTO-9 and propidium iodide fluorescent to stain for adherent bacteria and obseIved with CLSM. Fewer bacteria were observed in zirconia group than titanium group. However, there was no statistical difference between two groups. The experimental results demonstrate that zirconium oxide may be considered as a promising material for dental implant abutments.

Effect of RF power on the properties of transparent conducting zirconium-doped zinc oxide films prepared by RF magnetron sputtering

Transparent and conducting zirconium-doped zinc oxide films with high transparency and relatively low resistivity have been successfully prepared by radio frequency （RF） msgnetron sputtering at room temperature, The RF power is varied from 75 to 150 W. At first the crystallinity and conductivity of the film are improved and then both of them show deterioration with the increase of the RF power, The lowest resistivity achieved is 2.07 × 10^-3Ωcm at an RF power of 100W with a Hall mobility of 16cm^2V^-1s^-1 and a carrier concentration of 1.95 × 10^20 cm^-3. The films obtained are polycryetalline with a hexagonal structure and a preferred orientation along the c-axis, All the films have a high transmittance of approximately 92% in the visible range. The optical band gap is about 3.33 eV for the films deposited at different RF powers.

Properties of oxide coating on the surface of ZrH_(1.8) prepared by microarc oxidation with different positive voltages

Zirconia coatings as hydrogen permeation barriers were formed on disktype ZrHj.s substrate speci mens in phosphate solution system by microarc oxidation technique. Influence of positive voltage on hydrogen per meation barriers on the surface of zirconium hydride was investigated as the main factor. The thickness of total oxide layer increased from 42.5 to 55.0 ~tm the increase of positive voltage increasing from 325 up to 425 V. The permeation reduction factor （PRF） was observed under different voltages, which increased with the increasing positive voltages. The phase structure of oxide layer was monoclinic Zr02 and tetragonal ZrO1.88. No reduction reaction occured in the process of hydrogen escaping, and it indicates that hydrogen permeation through oxide layer is restricted.

Interfacial reaction between zirconium alloy and graphite mold/yttrium oxide ceramic mold

Zirconium alloys are active in the molten state and tend to react with the mold during casting. The casting technology of zirconium is not yet well established; especially in selecting the mold materials, which are diffi cult to determine. In the present work, the interfacial reactions between zirconium casting and casting mold were studied. The zirconium alloy was melted in a vacuum arc skull furnace and then cast into the graphite mold and ceramic mold, respectively. The zirconium casting samples were characterized using SEM, EDS and XRD with an emphasis on the chemical diffusion of elements. A reaction layer was observed at the casting surface. Chemical analysis shows that chemical elements C, O and Y from the mold are diffused into the molten zirconium, and new phases, such as ZrC, Zr3O, YO1.335 and Y6ZrO11, are formed at the surface. In addition, an end product of zirconium valve cast in a yttria mold has a compact structure and good surface quality.

Synthesis of mesoporous cerium-zirconium mixed oxides by hydrothermal templating method

Mesoporous cerium-zirconium mixed oxides were prepared by hydrothermal method using cetyl trimethyl ammonium bromide (CTAB) as template. The effects of amount of template, pH value of solution and hydrothermal temperature on mesostructure of samples were systematically investigated. The final products were characterized by XRD, TEM, FT-IR, and BET. The results indicate that all the cerium-zirconium mixed oxides present a meso-structure. At molar ratio of n(CTAB)/n((Ce)+(Zr))= 0.15, pH value of 9, and hydrothermal temperature of 120 ℃, the samples obtained possess a specific surface area of 207.9 m2/g with pore diameter of 3.70 nm and pore volume of 0.19 cm3/g.

Preparation of VPO Catalysts and Effect of Zirconium Promoter on the Selective Oxidation of Pentane

This study focuses on the effects of reducing solvents used in the preparation of vanadyl pyrophosphate （VPO）, and ZrO2 and （ZrO）2P2O7 promoters on the structure and catalytic performance of VPO catalysts. The VPO catalysts were prepared by the following steps： 1） Formation of vanadium phosphate by the reaction of V2O5 and H3PO4, 2） Synthesis of VPO precursor through the reduction of vanadium phosphate by reducing solvents, and 3） Activation of the precursor. For Zr promoted VPO, Zr was added to the precursor before activation. The P/V atomic ratios of different VPO catalysts, which were prepared by using different reducing solvents, were different. The precursor prepared by using isobutanol or isobutanol-benzyl alcohol contained VO（H2PO4）2 and VOHPO4·0.5H2O. The precursor prepared by using hexanol also contained VO（H2PO4）2 and VOHPO4·0.5H2O crystal phases, but the amount of VOHPO4·0.5H2O was much less than that of VO（H2PO4）2. After activation, all the VPO catalysts, prepared by using different reducing solvents, contained only the （VO）2P2O7 crystal phase. The VPO prepared by using isobutanol-petroleum ether as reducing solvent was the most active, while the VPO prepared by using hexanol had the lowest activity. Nevertheless, their total selectivity to phthalic and maleic anhydrides was almost the same. Both ZrO2 and （ZrO）2P2O7 promoters increased the activity and selectivity of VPO, but ZrO2 promoter increased the activity of VPO more drastically than （ZrO）2P2O7 promoter.

Self-assembling Synthesis of Vanadium Oxide Nanotubes and Simple Determination of the Content of V(IV)

High-yielding low-cost vanadium oxide nanotubes were prepared by the hydrothermal self-assembling process from vanadium pentoxide and organic molecules as structure-directing templates.Moreover,a new method was discovered for determining the content of V (IV) in vanadium oxide nanotubes by thermogravimetric analysis (TGA).This method is simple,precise and feasible and can be extended to determine the content of low oxidation state in the other transition metal oxide nanomaterials.

Experimental and Theoretical Study of Hydrogen Atom Abstraction from Ethylene by Stoichiometric Zirconium Oxide Clusters

有乙烯(C2H4 ) 的 cationic 锆氧化物簇(ZrxOy+) 的反应被使用结合的一个 time-of-flight 团分光计调查激光 ablation/supersonic 扩大簇来源。一些氢包含产品(ZrO2 )xH+(x = 14 ) 在反应以后被观察。功能的理论计算显示的密度除了普通的氧转移反应隧道，氢抽象隧道能也发生在(ZrO2 ) x++C2H4，它支持观察到(ZrO2 )xH+ 可能由于(ZrO2 ) x++C2H4 (ZrO2 ) xH++C2H3。不同反应隧道的率常数被 Rice-Ramsberger-Kassel-Marcus 理论也计算。

OXIDATIVE COUPLING OF METHANE OVER Na_2CO_3 DOPED ZIRCONIUM DIORIDE

Na_2CO_3/ZrO_2 catalyst shows a high activity of oxidative coupling of methane. It possesses stronger electron donor ability than that of ZrO_2 catalyst. The activation of methane is supposed to relate to the O_2^- or O_2^(2-) and O^- species.

Hydrothermal Synthesis and Characterization of a Novel Zirconium Oxide and Its Application as an Ion Exchanger

A novel hydrothermal zirconium oxide (ZrO2) ion exchange material was successfully synthesized by hydrothermal technique. The material has been characterized using different tools such as thermal analysis (DTA-TGA), FT-IR and X-ray diffraction studies. The results show that the prepared ZrO2 is pure and with a unique shape and it belongs to the hexagonal system. Chemical resistively of the material for various media such as, water, acids and bases have been assessed. The capacity of ZrO2 ion exchanger for Na+, Cu2+, Ni2+ and Zn2+ ions at natural pH has been determined. The effect of heating treatment for ZrO2 on ion exchange capacity was studied. The sorption/ion exchange behaviour of Cu2+, Ni2+ and Zn2+ ions towards ZrO2 in dif-ferent pH media has been investigated. The distribution coefficients and separation factors were determined. Finally, Freundlich isotherms for Cu2+, Zn2+ and Ni2+ ions on hydrothermal ZrO2 ion exchanger were inves-tigated and the Freundlich isotherm constants were conduced.

Energy-Exergy Analysis and Carbon (IV) Oxide Emission of an Aluminium Extrusion Plant in Nigeria

Energy security, cost of production and environmental constraints have necessitated the need for proper energy utilisation in the manufacturing industries. This work analysed energy and production data from an aluminium extrusion plant in Lagos, Nigeria for energy efficiency, exergy efficiency (or process?efficiency), energy cost per unit of production, CO2 emission and pollution?rate?index. The input-output energy analysis method was used to estimate the?embodied energy intensity. The pollution rate, energetic and exergetic efficiencies were estimated from the exergy analysis. The CO2 emission was estimated?from IPCC guideline on greenhouse inventories and the energy cost of unit?produce was estimated from energy cost accounting method. The five-year average thermal and electrical utilisation ratio was 45/55, which deviated from the 70:30 of the global best practices. The embodied energy intensity for the five years’ ranges between 2.31 - 162.3 GJ/t which is in excess of the recommended?range of (2.9 - 3.2 GJ/t). The mean energy efficiency for the five year was 79.4% and the mean exergetic efficiency was 57.8% indicating that production was well?managed (>50%) with energy wastages very high in boiler energy conversion. The total energy used was 16 MJ and CO2 emitted is 1.01 × 1011 g during the study period. The average pollution rate index for the plant was 0.8695 indicating that the plant is negatively impacting the environment due to technological limitation of the energy conversion process employed in the manufacturing plant. The study reveals a distortion of the recommended best practice in energy balance ratio which accounted for the high average cost of production (N 4418.3/t);process efficiency was generally low thereby negatively affecting industrial output for the company.

Effect of Zirconium Oxide Nano-Fillers Addition on the Flexural Strength, Fracture Toughness, and Hardness of Heat-Polymerized Acrylic Resin

Purpose: The mechanical strength of polymethyl methacrylate (PMMA) remains far from ideal for maintaining the longevity of denture. The purpose of this study was to evaluate the effect of Zirconium oxide (ZrO2) nanofillers powder with different concentration (1.5%, 3%, 5% and 7%) on the flexural strength, fracture toughness, and hardness of heat-polymerized acrylic resin. Materials and methods: Zirconium oxide powders with different concentrations (1.5%, 3%, 5% and 7%) were incorporated into heat-cure acrylic resin (PMMA) and processed with optimal condition (2.5:1 Powder/monomer ratio, conventional packing method and water bath curing for 2 hours at 95。C) to fabricate test specimens of PMMA of dimensions (50 × 30 × 30 mm) for the flexural strength, fracture toughness, and (50 × 30 × 30 mm) were fabricated for measuring hardness. PMMA without additives was prepared as a test control. Three types of mechanical tests;flexural strength, fracture toughness and hardness were carried out on the samples. The recorded values of flexural strength in (MPa), fracture toughness in (MPa.m1/2), and hardness (VHN) were collected, tabulated and statistically analyzed. One way analysis of variance (ANOVA) and Tukey’s tests were used for testing the significance between the means of tested groups which are statistically significant when the P value ≤ 0.05. Results: Addition of Zirconium oxide nanofillers to PMMA significantly increased the flexural strength, fracture toughness and hardness. Conclusion: These results indicate that Zirconium oxide nanofillers added to PMMA has a potential as a reliable denture base material with increased flexural strength, fracture toughness, and hardness. According to the results of the present study, the best mechanical properties were achieved by adding 7%wt ZrO2 concentration.

A New Biosensor for Glucose Based on Screen Printed Carbon Electrodes Modified with Tin (IV)-Oxide

Tin (IV) oxide was used as a bulk mediator in carbon paste and carbon ink screen-printed electrodes to improve the better performance of the carbon electrodes for the detection of hydrogen peroxide in comparison with unmodified electrodes. A new glucose biosensor developed from modified carbon paste electrode and coated with glucose oxidase entrapped in Nafion was investigated with a flow injection system. The biosensor could be operated under physiological conditions (pH 7.5, 0.1 M phosphate buffer), with an operating potential of ?200 mV (vs. Ag/AgCl), a flow rate of the carrier of 0.2 mL/min. and an injection volume of 100 μL. The amperometric response of the biosensor showed good linearity up to 200 mg/L with a detection limit (3σ) of 6.8 mg/L. The relative standard deviation for the repeatability of measurements for 100 mg/L glucose was 2.9% (n = 10 measurements) and the corresponding reproducibility was 12% (n = 5 sensors). The effect of all investigated interferences (uric acid, paracetamol, xanthine, hypoxanthine and ascorbic acid) was not fatal and could be eliminated by the use of the standard addition method. The new biosensor was successfully applied to the determination of glucose in human blood plasma.

Nickel sulfate solution fluoride separation with hydrous zirconium oxide

Fluoride is an impurity in nickel sulfate production,which is required for electric vehicle batteries.Hydrous zirconium oxide(HZO)was evaluated for removing fl uoride from nickel sulfate solution.Maximum fluoride removal occurred at pH value 4 and optimal pH value is 4–5,considering Zr solubility.Fluoride availability decreases with pH due to hydrogen fluoride and zirconium fluoride aqueous species.Fluoride removal is initially rapid,with 50 wt.%removal in 7 min,followed by slow removal up to 68 wt.%after 72 h and follows second order rate kinetics.Fluoride removal was dominated by an ion exchange mechanism and resulting Zr–F bonds were observed using Fourier-transform infrared spectroscopy.The presence of nickel sulfate decreased loading capacity compared to a salt-free solution.HZO maintained adsorption capacity through five cycles of loading and regeneration.

Reduction Band Gap Energy of TiO₂Assembled with Graphene Oxide Nanosheets

This research work aims to reduce the band gap of thin layers of titanium oxide by the incorporation of graphene oxide sheets. Thin layers of the TiO2-GO composites were prepared on a glass substrate by the spin-coating technique from GO and an aqueous solution of TiO2. A significant decrease in optical band gap was observed at the TiO2-GO compound compared to that of pure TiO2. Samples as prepared were characterized using XRD, SEM and UV-visible spectra. XRD analysis revealed the amorphous nature of the deposited layers. Scanning electron microscope reveals the dispersion of graphene nanofiles among titanium oxide nanoparticles distributed at the surface with an almost uniform size distribution. The band gap has been calculated and is around 2 eV after incorporation of Graphene oxide. The chemical bond C-Ti between the titanium oxide and graphene sheets is at the origin of this reduction.

Microstructure Study on Oxidation of Zirconium Diboride

The oxidation behaviors of fused zirconium diboride and chemosynthetic zirconium diboride as well as morphology and composition of their oxidation products were researched by FESEM-EDS and XRD.The two kinds of zirconium diboride were heated at 700℃,900℃,1100℃and 1300℃for 3 h in air,respectively.The results show that Zr02 and B203(Ⅰ)are generated from the chemosynthetic zirconium diboride oxidized at 700℃for 3 h or the fused zirconium diboride oxidized at 800℃for 24 h;B203(Ⅰ)dissolves into water and then H3B03 crystallizes.

The Oxidative Decarboxylation of Nitrilotriacetic Acid (NTA)——A Study of the Reaction of NTA with Cerium(Ⅳ) in HCIO_4

The reaction between Ce (IV ) and NTA was investigated titrimetrically and spectrophotometrically. Two equivalents of Ce( IV ) are reduced per mole of NTA almost instantaneously at room temperature. With increasing reaction time an ultimate of about 7 equivalents of Ce( IV) is consumed per mole of NTA at room temperature. Carbon dioxide, formaldehyde and dimethylamine are the major and readily detectable products of oxidation of NTA by Ce( IV ). The rates of the reaction in HClO4 were measured spectrophotometricaUy using the stopped flow technique. The effects of both acidity of the medium and added salts support and extend preliminary results.

Oxidative Rearrangement via Oxycerication with Ce(IV) Salt

A mild and reliable procedure for the preparation of alpha-arylpropanoic acids from arylpropanone by Ce(IV) salt oxidative rearrangement is discribed.