Synthesis of layered double hydroxides from eggshells

Ca-Al and Ca-Fe layered double hydroxides (LDHs) were successfully synthesized from chicken eggshells by an ultrasonic wave assistant method. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) techniques. XRD and TEM analyses showed that the 4Ca-Al LDHs were of high purity but other samples were not. The present study provides a simple, efficient and environmental friendly method to obtain LDHs from biowaste eggshells, in which additional alkaline solution is not required for synthesis. Moreover, eggshells provide all the requisite bivalent metal ions, which are needed to form layered double hydroxides.     

Microwave-assisted hydrothermal synthesis and characterizations of PrF3 hollow nanoparticles

PrF₃ hollow nanoparticles were synthesized by the microwave-assisted heating hydrothermal treatment of the corresponding colloidal rare earth fluorides precipitates. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The TEM imaging showed that the PrF₃ nanoparticles prepared in this way had hollow sphere-like morphology with the mean particle size of about 31 nm. XRD showed that the PrF₃ hollow nanoparticles had high purity and high crystallinity.     

Synthesis and in vitro investigation of sol-gel derived bioglass-58S nanopowders

The aim of this research is the synthesis of bioglass-58S nanopowders by sol-gel method. Also, the effect of aging time of parent sols on the morphology, structure and particle size was investigated. Bioglass-58S powders were analyzed by X-ray diffraction patterns (XRD), Fourier transform infrared spectroscopy (FTIR), zetasizer instrument, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD results showed that the powder is amorphous and glassy. According to FTIR spectroscopy, silicate bonds were formed in all powders. Zetasizer curves proved that the particle sizes of the powders and agglomerates have increased with aging time. The SEM images confirmed these results, too. Additionally, the TEM observations revealed that the increase of aging time caused the growth of grains with the size between 50?C200 nm. The in vitro biological behavior of bioglass-58S powders were investigated by immersing the bioglass discs (made from the powders) in the simulated body fluid (SBF). The XRD patterns and SEM images confirmed the formation of the hydroxyapatite (HA) phase.     

Preparation and characterization of nanoboron by cryo-milling

Cryo-milling of coarse micron grade elemental boron powder was investigated for possible generation of nanosized boron powder. Process parameters were optimized for the least contamination and least particle size. The as-milled powders were characterized by scanning and transmission electron microscopy (SEM/TEM) and x-ray diffraction (XRD) for powder morphology, average particle size, and phase analysis. The particle size and surface area were also estimated using dynamic laser scattering (DLS) and BET techniques to correlate with the performance of the material. Thermo-gravimetric and differential thermal analysis (TG-DTA) studies were performed to ascertain mass change and energy release in unmilled and milled powder. The average particle size of boron powder after 9 h of cryo-milling was<100 nm. The cryo-milled powder was made air-stable and dispersible in JP10 fuel by coating it with ligand through the mechanical milling method. The TOPO (tri-n-octyl phosphine oxide) coated nano boron powder exhibited dispersion stability for a week.     

A novel route for synthesis of nanocrystalline hydroxyapatite from eggshell waste

The eggshell waste has been value engineered to a nanocrystalline hydroxyapatite (HA) by microwave processing. To highlight the advantages of eggshell as calcium precursor in the synthesis of HA (OHA), synthetic calcium hydroxide was also used to form HA (SHA) following similar procedure and were compared with a commercially available pure HA (CHA). All the HAs were characterized by X-ray powder diffraction (XRD) method, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and specific surface area measurements. Nanocrystalline nature of OHA is revealed through characteristic broad peaks in XRD patterns, platelets of length 33−50 nm and width 8–14 nm in TEM micrograph and size calculations from specific surface area measurements. FT-IR spectra showed characteristic bands of HA and additionally peaks of carbonate ions. The cell parameter calculations suggest the formation of carbonated HA of B-type. The OHA exhibits superior sinterability in terms of hardness and density than both SHA and CHA may be due to larger surface area of its spherulite structure. The in vitro dissolution study shows longer stability in phosphate buffer and cell culture test using osteoblast cells establishes biocompatibility of OHA.     

From eggshells biowaste to hydroxyapatite biomaterial

In the present study a biowaste, in the form of chicken eggshells, is used for producing a biomaterial – hydroxyapatite by a conventional chemical precipitation method. Hydroxyapatite is a major component of human hard tissues, such as bones and teeth, which makes it a paradigmatic bioactive material. The first step in the synthesis of hydroxyapatite from eggshells is the transformation of their main component calcium carbonate into calcium oxide at 1000   °C. Afterwards, calcium oxide is hydrated in order to produce calcium hydroxide. Hydroxyapatite is then synthesized by the addition of the phosphoric acid. The phase composition of the eggshells is examined by the powder X‐ray diffraction. The surface morphology of the sintered product is determined by the scanning electron microscope equipped with the energy dispersive spectrometer. Powder X‐ray diffraction and scanning electron microscope analyses confirmed hydroxyapatite as the main phase of the final product. The reuse of chicken eggshells reduces the amount of biowaste, as well as the need for the biowaste management. This investigation shows that the eggshells can be a useful raw material for the synthesis of valuable biomaterials.     

Evaluation and characterization of nanostructure hydroxyapatite powder prepared by simple sol-gel method

Many attempts have been focused on preparing of synthetic hydroxyapatite (HA), which closely resembles bone apatite and exhibits excellent osteoconductivity. Low temperature formation and fusion of the apatite crystals have been the main contributions of the sol-gel process in comparison with conventional methods for HA powder synthesis. This paper describes the synthesis of nano-HA particles via a sol-gel method. Nanocrystalline powder of hydroxyapatite (HA) was prepared using Ca(NO₃)₂·4H₂O and P₂O₅ by a simple sol-gel approach. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used for characterization and evaluation of the phase composition, morphology and particle size of products. The presence of amorphous and crystalline phases in the as-dried gel precursor was confirmed by the evaluating technique. Single phase of HA was also identified in the heat treated powder by XRD patterns. SEM and TEM evaluations showed that the obtained powder after heat treatment at 600 °C was agglomerated and composed of nanocrystalline (25-28 nm) HA particles. Increasing the sintering temperature and time could cause decomposition of HA into β-tricalcium phosphate and calcium oxide. The prepared nanocrystalline HA is able to improve the contact reaction and the stability at the artificial/natural bone interface for medical applications.     

Synthesis and characterization of nanocrystalline MgAl2O4 spinel via sucrose process

Nanocrystalline MgAl₂O₄ spinel powder was synthesized using metal nitrates and a polymer matrix precursor composed of sucrose and polyvinyl alcohol (PVA). The precursor and the calcined powders were characterized by simultaneous thermal analysis (STA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). According to XRD results, the inceptive formation temperature of spinel via this technique was between 600 and 700 °C. The calcined powder at 800 °C for 2 h has faced shaped morphology and its crystallite size is in the range of 8-12 nm. Further studies also showed that the amount of polymeric matrix to metal ions has significant influence on the crystallite size of synthesized magnesium aluminate spinel powder.     

Determination of size distributions in nanosized powders by TEM,XRD, and SAXS

Crystallite size distributions and particle size distributions were determined by transmissions electron microscopy (TEM), X-ray powder diffraction (XRD), and small-angle X-ray scattering (SAXS) for three commercially available TiO₂ powders (P25, UV100, and TiO2_5?nm) and one SSEC produced powder (SSEC78). The theoretical Guinier model was fitted to the experimental obtained XRD data and compared to analytical expressions. Modeling of the XRD spectra showed a difference between the analytical size dependent expressions and the theoretical Guinier model. Primary particle size distributions were extracted from SAXS measurements by the hard sphere model including an interparticle interference factor. The sizes obtained from SAXS were smaller than the sizes obtained from the XRD experiments; however, a good agreement was obtained between the two techniques. Electron microscopy confirmed the primary particle sizes and the shapes obtained by XRD and SAXS. The SSEC78 powder and the commercially available powders showed different morphologies, but SSEC78, UV100, and TiO2_5?nm all consisted of both primary particles as well as a secondary structure comprised of nanosized primary particles agglomeration into larger clusters. P25 showed the largest primary particle size, but did not show a secondary structure.     

Preparation and characteristics of nanosized carbonated apatite by urea addition with coprecipitation method

Nanosized carbonated apatites (CAp) were prepared by coprecipitation method with urea addition at pH 8 and pH 12 with 12 hours aging, which resulted in needle-like and rod-like structures, respectively. From examining the XRD patterns, it was determined that the as-prepared powders contained no crystalline phase other than CAp. However, the powder prepared at pH 8 partially transforms to β-tricalcium phosphate (β-TCP) after heat treatment at 900 °C. Under heat treatment, powder prepared at pH 12 is more stable than powder prepared at pH 8. In addition, the as-prepared powders at pH 8 with 12 hours aging yield needle-like calcium deficient apatite (CDA) with substitution of CO₃^2? for PO₄^3? in low content. Their particle size is about 20 nm in width and 200–300 nm in length. The as-prepared powders at pH 12 for 12 hours aging result in rod-like nanostructures about 50 nm in diameter and 300 nm in length with 8.2 wt.% CO₃^2?, which is similar to human bone composition. Various characteristic analyses of CAp have been employed including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and transmission electron microscopy (TEM).     

Preparation of nanostructured NiFe2O4 catalysts by combustion reaction

Nanosize nickel ferrite powders (NiFe₂O₄) have been prepared by combustion reaction using nitrates and urea as fuel. The resulting powders were characterized by X-ray diffraction (XRD), nitrogen physical adsorption (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and catalytic activity. The results showed nanosize nickel ferrite powders with high specific surface area (55.21 m²/g). The powders showed extensive XRD line broadening and the crystallite size calculated from the XRD line broadening was 18.0 nm. The nickel ferrite powder presented significant activity as catalyst for the water gas shift reaction, over the temperature range of 250–450 °C.     

Preparation and characterization of nanometer-scale powders ceria by electrochemical deposition method

Ceria (CeO₂) nanoparticles of 10-30 nm in average particle size have been synthesized via electrochemical deposition method in cerium(III) chloride solution with an undivided cell as electrochemical cell and ethanol-acetylacetone as additives. X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transformation infrared spectroscopy (FT-IR) and thermal analysis (TG-DTA) are introduced to characterize the samples. The results indicate that the as-prepared powders after being treated at 650 °C are nanocrystalline with the cubic fluorite structure and the sphericity in shape. It is revealed that the size of ceria nanoparticles can be decreased effectively by adding the ethanol-acetylacetone solution. In addition, the possible formed mechanism of CeO₂ nanometer-scale powder. The role of additive is also investigated in this paper.     

Silver nanorods using HEC as a template by γ-irradiation technique and absorption dose that changed their nanosize and morphology

Silver (Ag) nanorods with average diameters of 20 nm and lengths up to 250 nm were successfully prepared in large scale using hydroxyethyl cellulose (HEC) as a template reducing silver nitrate by γ-irradiation. When we changed the irradiation time to get a different absorption dose at the same dose rate, we can find that the silver nanorods have been transferred into a larger size and another morphology. The particle size and morphology can be changed by choosing different absorption doses under the same dose rate. The products were characterized by transmission electron microscopy (TEM), electron diffraction (ED) analysis, field-emission scanning electron microscopy (FESEM), X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).     

Preparation and characterization of nano-hydroxyapatite powder using sol-gel technique

Hydroxyapatite (HA) nano powders (20–60 nm) were synthesized using a sol-gel route with calcium nitrate and phosphoric acid as calcium and phosphorus precursors, respectively. Double distilled water was used as a diluting media for HA sol preparation and ammonia was used to adjust the pH. After aging, the HA gel was dried at 65°C and calcined to different temperatures ranging from 200–800°C. The dried and calcined powders were characterized for phase composition using X-ray diffractometry, elemental dispersive X-ray and Fourier transform infra-red spectroscopy. The particle size and morphology were studied using transmission electron microscopy. Calcination revealed HA nano powders of increased particle size and crystallinity with increase in temperature. For all calcinations temperatures, the particle size distribution analysis of HA powders showed skewed distribution plot. At temperature of 700°C and above, formation of CaO was noticed which was attributed to phosphorous volatilization. This study showed that high purity HA with varying degrees of crystallinity could be obtained using this simple technique.     

The role of albumen (egg white) in controlled particle size and electrical conductivity behavior of zinc oxide nanoparticles

The size controlled zinc oxide nanoparticle is synthesized in the isothermal evaporation method with albumen (egg white). This method is simple and cost effective for synthesis of ZnO nano powder. The egg white foam was assisted to increase the reaction rate and produce the zinc oxide nano powder. This method helps to attain the particle size in the range 13-28 nm. The results from X-ray diffraction patterns and TEM micrograph confirmed the formation of nano crystalline phase with particle size ranges from 13 nm to 28 nm. The samples were further analyzed by using Fourier transform Infrared spectroscopy (FT-IR), photoluminescence spectrum (PL), thermogravimetric analysis (TGA) and Resistivity measurement. The less time consumption in isothermal evaporation process was one of the significant roles for large scale zinc oxide nano powder production.     

The role of albumen (egg white) in controlled particle size and electrical conductivity behavior of zinc oxide nanoparticles

The size controlled zinc oxide nanoparticle is synthesized in the isothermal evaporation method with albumen (egg white). This method is simple and cost effective for synthesis of ZnO nano powder. The egg white foam was assisted to increase the reaction rate and produce the zinc oxide nano powder. This method helps to attain the particle size in the range 13–28 nm. The results from X-ray diffraction patterns and TEM micrograph confirmed the formation of nano crystalline phase with particle size ranges from 13 nm to 28 nm. The samples were further analyzed by using Fourier transform Infrared spectroscopy (FT-IR), photoluminescence spectrum (PL), thermogravimetric analysis (TGA) and Resistivity measurement. The less time consumption in isothermal evaporation process was one of the significant roles for large scale zinc oxide nano powder production.     

镍纳米粉的阳极弧等离子体制备与粒度研究

采用阳极弧放电等离子体方法成功制备了高纯镍纳米粉体并对其粒度进行表征.采用X射线衍射(XRD)测试样品的物相和结构,并用Scherrer公式计算晶粒粒度;采用透射电子显微镜(TEM)分析样品的形貌、结构和粒度分布;采用表面吸附仪测定样品的N2吸附-脱附等温线,并由BET理论模型计算出样品的比表面积和颗粒粒度.实验结果表明:本法所制备的镍纳米的晶体结构与相应的块体材料基本相同,为fcc结构的晶态,呈规则的球形链状分布,比表面积为14.23m2/g,粒径范围分布在(20～70) nm,平均粒径为47 nm,三种方法测得的结果基本一致.     

Synthesis and characterization of hydroxyapatite, fluoride-substituted hydroxyapatite and fluorapatite

Powders of hydroxyapatite (HA), partially fluoride-substituted hydroxyapatite (fHA), and fluorapatite (FA) were synthesized in house using optimum methods to achieve relatively pure powders. These powders were assessed by the commonly used bulk techniques of X-ray diffraction (XRD), Fourier transform infra-red (FTIR) and FT-Raman spectroscopies, inductively coupled plasma atomic emission spectroscopy (ICP-AES), and F-selective electrode. In addition, the current study has employed transmission electron microscopy (TEM), involving morphological observation, electron diffraction and energy-dispersive X-ray spectrometry (EDX), as an effective analytical technique to evaluate the powders at a microscopic level. The HA and fHA particles were elongated platelets about 20×60 nm in size, while FA particles were over twice this size. Calcination of the HA and fHA powders at 1000 °C for 1 h resulted in increased grain size and crystallinity. The calcined fHA material appeared to possess a crystal structure intermediate between HA and FA, as evidenced by the (3 0 0) peak shift in XRD, as well as by the position of the hydroxyl bands in the FTIR spectra. This result was consistent with electron diffraction of individual particles. Small levels of impurities in some of the powders were identified by EDX and electron diffraction, and the carbonate content was detected by FTIR. The use of TEM in conjunction with the bulk techniques has allowed a more thorough assessment of the apatites, and has enabled the constituents in these closely related apatite powders to be identified.     

Characterization of nano-crystalline ZrO2 synthesized via reactive plasma processing

Nano-crystalline ZrO₂ powder has been synthesized via reactive plasma processing. The synthesized ZrO₂ powders were characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM) and FTIR spectroscopy. The synthesized powder consists of a mixture of tetragonal and monoclinic phases of zirconia. Average crystallite size calculated from the XRD pattern shows that particles with crystallite size 20 nm or less than 20 nm are in tetragonal phase, whereas particles greater than 20 nm are in the monoclinic phase. TEM results show that particles have spherical morphology with maximum percentage of particles distributed in a narrow size from about 15 nm to 30 nm.     

A Green Chemical Synthesis and Characterization of Mn3O4 nanoparticles

Mn₃O₄ nanoparticles were synthesized via an ionic liquid (IL) assisted process at room temperature, which is rather difficult to achieve by other techniques. The synthesized product was characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetry (TG), and vibrating sample magnetometry (VSM). The prepared material showed a high purity, while crystallite size and particle size agree well with each other, 17±2 and 19±3?nm, respectively, revealing nearly single crystalline character of nanoparticles. The product contains 4?wt% of adsorbed water and ionic liquid. This method provides a facile, one-step, and low-cost route for the synthesis of nanostructures of metal oxides. In addition, [BMIM]BF₄ could be collected and reused for subsequent reactions.