Decomposition Of Zinc Acetate Research Articles

Growth of Vertical ZnO Nanorods from Patterned Films via Decomposition of Zinc Acetate by Focused Ion Beam: Implication for UV Detection

Growth of Vertical ZnO Nanorods from Patterned Films via Decomposition of Zinc Acetate by Focused Ion Beam: Implication for UV Detection

Growing nearly vertically aligned ZnO nanorod arrays on porous α-Al2O3 membranes to enhance the separation of MTBE from aqueous solution

The separation of methyl tertiary butyl ether (MTBE) from aqueous solution by pervaporation-based membrane technology has attracted much attention recently. The present work proposed a novel strategy to enhance the MTBE/water separation performance of porous α-Al2O3 membranes. ZnO seeds were planted on the surface of α-Al2O3 membranes by the deposition and decomposition of zinc acetate, followed by growing ZnO nanorod arrays (ZNA) on the seeded α-Al2O3 membranes by hydrothermal reaction in the mixed hydrated zinc nitrate (HZN) and hexamethylenetetramine (HMTA) solution. Finally, the membranes were hydrophobized by grafting fluoroalkylsilane (FAS) onto their surface. The results show that the MTBE/water separation factor has been dramatically promoted from 7.7 for the α-Al2O3 membranes to 55.7 for the ZNA-covered α-Al2O3 membranes. The promotion may be attributed to the nearly vertically aligned ZnO nanorod arrays, which provide much surface area to load more fluorocarbon groups that are amiable to MTBE molecules and supply a superhydrophobic surface. The MTBE in the permeate mixture has been concentrated to as high as 72.9 wt%, in striking contrast to 4.6 wt% in the feed solution. The obtained membranes are highly stable upon long-term operation.

Preparation and characterization of zinc oxide nanoparticles

Zinc oxide nanoparticles are important inorganic particles which receive great interest over the past few years because of the wide nanotechnology application in various fields of material physics and chemistry. The physicochemical properties of resulting ZnO nanoparticles can be controlled by the synthesis route, method of preparation and parameters related to condition processing. In this study, ZnO nanoparticles were successfully synthesized by three different methods namely polyol method, solvothermal method and co-precipitation method. X-ray diffraction (XRD) patterns show that the all resulting ZnO nanoparticles materials which were synthesized by all the three different methods are pure phase with good crystalinity and completely matched the hexagonal-wurzite structure. The presence of a broad and sharp absorption band at around 440 cm-1 in the FTIR spectrum further confirmed the existence of ZnO phase. In polyol method, ZnO nanoparticles were successfully synthesized under hydrothermal condition. Zinc acetate (ZnAc) was dissolved and heated in three different glycol solutions, namely ethylene glycol (EG), diethylene glycol (DEG) and trietyleneglycol (TEG). The effect of different glycol solutions and calcination on the formation of ZnO nanoparticles was investigated. Single-modal narrow particle size distribution of ZnO nanoparticles with average particles size of 2 ± 1 nm, 12 ± 1nm and 13 ± 1 nm were obtained when EG, DEG and TEG were used in the synthesis, respectively. The broadness of the size distribution of the ZnO nanoparticles can be given as EG > DEG >TEG. The specific surface areas of all the resulting materials however show very similar values ranging from 12.2 to 13.5 m2g-1. The low-temperature solvothermal process was employed as the second method to synthesize ZnO nanoparticles. The initial concentration of zinc acetate was controlled and this process is based on the decomposition of zinc acetate and sodium hydroxide (NaOH) in a mixture solution of ethanol and EG. The effect of different zinc acetate concentration and the effect of organic solvent mixtures solution between ethanol and EG can be shown by a single modal narrow particle size distribution with the average size below 25 ± 1 nm. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analysis revealed that less macroscopic agglomeration of ZnO nanoparticles, indicating that the effect of low temperature process in the mixtures solution also contributed to the higher specific surface area of about 40 m2g- 1. Further effect of high calcinations temperature on the physicochemical properties of the resulting ZnO nanoparticles shows more crystalline and pure phase. However, the increasing particles size resulted in the decreasing of specific surface area due to the compact agglomeration of ZnO particles. Lastly, an intermediate zinc oxalate phase was synthesized by oxalate coprecipitation from nearly saturated solution of zinc acetate and 2-propanol of oxalic acid solution. Highly crystallized and pure phase ZnO nanoparticles were successfully synthesized by thermal treatment at 400 to 600 oC for 4 hours. Single-modal narrow particle size distribution of ZnO nanoparticles with the average particles size of 3± 1 nm , 28 ± 1 nm and 25 ± 1 nm are obtained at 400, 500 and 600 oC, respectively. FESEM and TEM also revealed the different surface structure and morphology of ZnO nanoparticles obtained at calcination temperatures. A huge reduction of specific surface area of ZnO nanoparticles from 22.9 m2g-1 to 2.6 m2g-1 was observed when the calcination temperature is increased from 400 to 600 oC. This study verified, a good crystallinity, high purity, small particle size and large specific surface area of ZnO nanoparticles can be obtained using all the methods. The effect of preparation parameters in each method gives the most influence to physichochemical properties of the resulting material.

Vibrational Order, Structural Properties, and Optical Gap of ZnO Nanostructures Sintered through Thermal Decomposition

The sintering of different ZnO nanostructures by the thermal decomposition of zinc acetate is reported. Morphological changes from nanorods to nanoparticles are exhibited with the increase of the decomposition temperature from 300 to 500°C. The material showed a loss in the crystalline order with the increase in the temperature, which is correlated to the loss of oxygen due to the low heating rate used. Nanoparticles have a greater vibrational freedom than nanorods which is demonstrated in the rise of the main Raman mode (high) during the transformation. The energy band gap of the nanostructured material is lower than the ZnO bulk material and decreases with the rise in the temperature.

Antibacterial Activities of Nano Magnetite ZnO Produced in Aerobic and Anaerobic Condition by Pseudomonas stutzeri

Background: Zincite (ZnO) nanoparticles are usually prepared by decomposition of zinc acetate, hot injection and heating-up method. Microbial nanoparticle production has been developed recently, since they are clean, nontoxic and cheap. Bacteria are known as environmentally friendly nanoparticle factories using cheap, renewable carbon sources. Nanometer-sized nanoparticles are talented for different applications. For example, semiconductor nanoparticles such as Sphalerite (ZnS) are used as fluorescence probes for labeling of biological tissues. These days, magnetic nanoparticles are applied routinely in magnetic resonance imaging (MRI) as contrast-enhancement agents. Also, nano ZnO is useful in petrochemical industries. Objectives: The aim of this study was to produce nanoparticles such as ZnO, ZnS, and Zn by using biofilm of a resistant bacterium (i.e. Pseudomonas stutzeri) on a piece of pure zinc. Materials and Methods: P. stutzeri strain CS-2 was isolated from enriched soil containing methyl tertiary butyl ether (MTBE). Since the bacterium has many metal resistance genes, it was a good candidate for producing nanoparticles. A piece of pure zinc metal, sized 3.1cm was put on a solid medium (nutrient agar). The biofilm was isolated and analyzed by X-Ray diffractometer (XRD). The optimum environmental condition for producing nanoparticles was investigated. Moreover, antibacterial activity as well as magnetic property of the produced nanoparticles was studied. Finally, PCR reaction for specific PST gene was done. Results: Analysis by XRD showed 78.1% ZnO (sized 24 nm), 2.5% Zn (sized 44.88 nm) and 4.8% ZnS (sized 12 nm) produced by P. stutzeri. The nanoparticles showed anti-bacterial activity against some of the Gram positive and negative bacteria. In addition, the nanoparticles showed magnetic properties. The best condition for nano zinc production was at pH 7, in the light and at 37 °C. CzcC gene with 399Kb was detected from the isolated P. stutzeri. Conclusions: Although previous studies have shown that P. stutzeri is able to produce silver nanoparticles in silver salt solution, but in this study, for the first time ZnO, ZnS, and Zn nanoparticles were detected on a biofilm of zinc metal. Isolation of these nanoparticles by this method is very cost effective, non-toxic, clean and compatible to Eco (green chemistry).

Production of nano zinc, zinc sulphide and nanocomplex of magnetite zinc oxide by Brevundimonas diminuta and Pseudomonas stutzeri

ZnO (Zincite) nanoparticle has many industrial applications and is mostly produced by chemical reactions, usually prepared by decomposition of zinc acetate or hot-injection and heating-up method. Synthesis of semi-conductor nanoparticles such as ZnS (Sphalerite) by ultrasonic was previously reported. In this work, high-zinc tolerant bacteria were isolated and used for nano zinc production. Among all isolated microorganisms, a gram negative bacterium which was identified as Brevundimonas diminuta could construct nano magnetite zinc oxide on bacterial surface with 22 nm in size and nano zinc with 48.29 nm in size. A piece of zinc metal was immersed in medium containing of pure culture of B. diminuta. Subsequently, a yellow-white biofilm was formed which was collected from the surface of zinc. It was dried at room temperature. The isolated biofilm was analysed by X-ray diffractometer. Interestingly, the yield of these particles was higher in the light, with pH 7 at 23°C. To the best of the authors knowledge, this is the first report about the production of nano zinc metal and nano zinc oxide that are stable and have anti-bacterial activities with magnetite property. Also ZnS (sized 12 nm) produced by Pseudomonas stutzeri, was studied by photoluminescence and fluorescent microscope.

Enhancement in field emission characteristics of multifunctional ZnO/C hybrid nanostructures

Multifunctional hybrid nanostructures have recently drawn immense attention due to their interesting physical and chemical properties and also due to their potential for applications in novel electronic devices. Herein, we report the luminescence and enhancement of field emission (FE) properties of multifunctional ZnO/C hybrid nanostructures prepared by the decomposition of zinc acetate and dextrose inside the nanopores of anodic aluminium oxide templates, which are fabricated by controlled electrochemical anodization of pure aluminium. Microscopic investigations show that the average pore diameter of the as prepared templates is ∼50 nm and ZnO/C hybrid nanostructures are formed around the inner pore walls. The template, containing the ZnO/C hybrids, exhibits visible light emission in blue wavelength region along with luminescence in the ultra-violet region. Investigations on the field emission property of the hybrid ZnO/C nanostructures reveals, that they are better and more efficient field emission material compared to one dimensional ZnO nanostructures.

A Theoretical Investigation of the Thermal Decomposition of Zinc Acetate and Zn-Oxo Complex Based on the Pyrolysis Characteristics of the Zinc-Containing Spent Catalyst

Zinc acetate and Zn-oxo complex of Zn4O(CH3COO)6 containing in the spent catalyst of vinyl synthesis were investigated by means of the first principles of density functional (DFT) methods. The geometries, energies, charge populations and local electron density distributions of the two compounds and their formate analogues were analyzed. Based on the pyrolysis characteristics of the spent catalyst, the thermodynamic properties of ΔG, ΔH and ΔS for possible decomposition reactions of zinc acetate and Zn4O(CH3COO)6 were calculated as functions of temperature. The results provide a theoretical evidence that Zn4O(CH3COO)6 is more stable than zinc acetate due to the regular Zn4O and ZnO4 tetrahedral coordination between Zn atoms and two kinds of O atoms. The preparation of Zn4O(CH3COO)6 via the hydrolysis of zinc acetate is thermodynamically feasible. Zn4O(CH3COO)6 is further decomposed into ZnO via a decarboxylation reaction rather than a hydrolysis reaction.

Enhanced sunlight photocatalytic performance of Sn-doped ZnO for Methylene Blue degradation

In the present study, nano-structured ZnO and Sn-doped ZnO photocatalysts with high sunlight photocatalytic activity were successfully synthesized through the decomposition of zinc acetate and glucose by microwave heating. The prepared ZnO and Sn-doped ZnO photocatalyst were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence spectrum (PL), UV–vis absorption spectrum (UV–vis), N 2 adsorption and UV–vis diffuse reflectance spectra (DRS). The results showed that the doping greatly changed the microstructure, morphology and optical properties of ZnO, which may contribute to the enhancement of photocatalytic activity. The sunlight photocatalytic activity of the prepared pure ZnO and Sn-doped ZnO photocatalyst was investigated by the degradation of Methylene Blue (MB) solution under sunlight irradiation. Compared with pure ZnO, 13% higher decolorization rate and 29–52% higher mineralization efficiency were obtained by the Sn-doped ZnO. The results indicated that Sn-doped ZnO had a higher photocatalytic activity and Sn dopant greatly increased the photocatalytic activity of ZnO.

Synthesis and Structure of Polyethylene-Matrix Composites Containing Zinc Oxide Nanoparticles

Nanocomposites of high-pressure polyethylene and zinc oxide nanoparticles are synthesized through thermal decomposition of zinc acetate. The phase composition of the nanocomposites is determined by x-ray diffraction (XRD), and the average size of ZnO nanoparticles is evaluated by transmission electron microscopy. The average size of the nanoparticles varies from 1 to 10 nm, depending on the ZnO content of the material. Both XRD and EXAFS results indicate that the zinc oxide nanoparticles have the wurtzite structure.

General Route to Vertical ZnO Nanowire Arrays Using Textured ZnO Seeds

A method for growing vertical ZnO nanowire arrays on arbitrary substrates using either gas-phase or solution-phase approaches is presented. A approximately 10 nm-thick layer of textured ZnO nanocrystals with their c axes normal to the substrate is formed by the decomposition of zinc acetate at 200-350 degrees C to provide nucleation sites for vertical nanowire growth. The nanorod arrays made in solution have a rod diameter, length, density, and orientation desirable for use in ordered nanorod-polymer solar cells.

γ-irradiation effects on kinetics and mechanism of the thermal decomposition of zinc acetate

The kinetics of the thermal decomposition of un-irradiated (pristine) and pre-γ-irradiated dehydrated zinc acetate was studied in the temperature range (553–573 K) and in air using both isothermal and dynamic thermogravimetric techniques. The data were analyzed using various solid state reaction models. The integral method using the Coats–Redfern equation was applied in the dynamic data analysis. The results showed that the kinetics of isothermal decomposition of dehydrated zinc acetate was governed by a phase-boundary controlled reaction (R 2) while in non-isothermal (dynamic) decomposition the kinetic was controlled by a nucleation process. The activation energies of the main decomposition process for un-irradiated and pre-γ-irradiated samples were calculated and the results of the isothermal and dynamic integral methods were compared and discussed. The changes in texture and crystal structure of the investigated zinc acetate by γ-irradiation were studied using electron microscopy and X-ray diffraction techniques.