scholarly journals Evaluating the buffering and acid-resistant properties of eggshell–titanium dioxide composite against erosive acids

2019 ◽  
Vol 17 (1) ◽  
pp. 228080001880991 ◽  
Author(s):  
Stanley Chibuzor Onwubu ◽  
Phumlane Selby Mdluli ◽  
Shenuka Singh
Keyword(s):  
Titanium Dioxide ◽  
Citric Acid ◽  
Acid Resistance ◽  
Test Results ◽  
X Ray Diffraction ◽  
Acid Attack ◽  
X Ray ◽  
Ph Values ◽  
Transmission Electron ◽  
Average Slope

Objective: This paper reports on the buffering and acid-resistant properties of a modified eggshell–titanium composite against citric acid attack. Materials and Methods: Eggshell–titanium EB-TiO2 was prepared by ball-milling eggshell powder and titanium dioxide. Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Transmission Electron Microscopy (TEM) were used to characterize EB-TiO2. The buffering property against citric acid at pH values of 2, 4, and 5 was measured using a pH meter. Five brands of toothpaste (Colgate, Colgate Sensitive, Aquafresh, Oralwise, and Sensodyne) were used to assess the acid-resistant properties of EB-TiO2. Enamel models were simulated by dissolving each brand of toothpaste with eggshell (control) and EB-TiO2. The samples were exposed to citric acid of pH 2. The average slope (kPa/s) was measured using a pressure sensor. An analysis of variance was used to analyze the kPa/s values (α =.05). Results: The FTIR and XRD analyses suggest the surface modification of EB-TiO2. The TEM image revealed spherical-shaped particles in EB-TiO2. The pH test results showed that the buffering properties of eggshell and EB-TiO2 were comparable. Significant differences were observed in the acid resistance properties of the samples exposed to citric acids ( P < .05). The Colgate toothpaste infused with eggshell powder had the highest mean kPa/s values, whereas Sensodyne infused with EB-TiO2 had the lowest kPa/s values. Conclusion: The salient features of this study indicate that modification of eggshell with titanium dioxide does not affect its carbonate buffering properties. Connecting the kPa/s values to acid-resistant properties, EB-TiO2 effectively reduces erosive attacks when added to toothpaste.

Crystalline phase transformation of colloidal cadmium sulfide nanocrystals

2017 ◽  
Vol 31 (06) ◽  
pp. 1750037
Author(s):  
M. Ghali ◽  
A. M. Eissa ◽  
M. M. Mosaad
Keyword(s):  
Phase Transformation ◽  
Optical Absorption ◽  
Crystalline Phase ◽  
Growth Conditions ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
X Ray ◽  
Ph Values ◽  
Transmission Electron

In this paper, we give a microscopic view concerning influence of the growth conditions on the physical properties of nanocrystals (NCs) thin films made of CdS, prepared using chemical bath deposition CBD technique. We show a crystalline phase transformation of CdS NCs from hexagonal wurtzite (W) structure to cubic zincblende (ZB) when the growth conditions change, particularly the solution pH values. This effect was confirmed using X-ray diffraction (XRD), transmission electron microscopy (TEM), optical absorption and photoluminescence (PL) measurements. The optical absorption spectra allow calculation of the bandgap value, [Formula: see text], where significant increase [Formula: see text]200 meV in the CdS bandgap when transforming from Hexagonal to Cubic phase was found.

scholarly journals Core-shell Fe3O4@zeolite NaA as an Adsorbent for Cu2+

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5047
Author(s):  
Jun Cao ◽  
Peng Wang ◽  
Jie Shen ◽  
Qi Sun
Keyword(s):  
Adsorption Capacity ◽  
Adsorption Process ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
Transmission Electron ◽  
Monolayer Adsorption ◽  
Zeolite Naa ◽  
Infrared Spectrometer

Here, using Fe3O4@SiO2 as a precursor, a novel core-shell structure magnetic Cu2+ adsorbent (Fe3O4@zeolite NaA) was successfully prepared. Several methods, namely X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), Transmission electron microscope (TEM), Brunauer Emmett Teller (BET) and vibrating sample magnetometry (VSM) were used to characterize the adsorbent. A batch experiment was conducted to study the Cu2+ adsorption capacity of Fe3O4@zeolite NaA at different pH values, contact time, initial Cu2+ concentration and adsorbent does. It is found that the saturated adsorption capacity of Fe3O4@zeolite NaA on Cu2+ is 86.54 mg/g. The adsorption isotherm analysis shows that the adsorption process of Fe3O4@zeolite NaA to Cu2+ is more consistent with the Langmuir model, suggesting that it is a monolayer adsorption. Adsorption kinetics study found that the adsorption process of Fe3O4@zeolite NaA to Cu2+ follows the pseudo-second kinetics model, which means that the combination of Fe3O4@zeolite NaA and Cu2+ is the chemical chelating reaction. Thermodynamic analysis shows that the adsorption process of Fe3O4@zeolite NaA to Cu2+ is endothermic, with increasing entropy and spontaneous in nature. The above results show that Fe3O4@zeolite NaA is a promising Cu2+ adsorbent.

scholarly journals Application of Titanium Dioxide-Graphene Composite Material for Photocatalytic Degradation of Alkylphenols

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Chanbasha Basheer
Keyword(s):  
Electron Microscopy ◽  
Titanium Dioxide ◽  
Photocatalytic Efficiency ◽  
Ionization Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Graphene Composite ◽  
Flame Ionization ◽  
Transmission Electron ◽  
Wastewater Samples

Titanium dioxide-graphene (TiO2-G) composite was used for the photodegradation of alkylphenols in wastewater samples. The TiO2-G composites were prepared via sonochemical and calcination methods. The synthesized composite was characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), and fluorescence spectroscopy. The photocatalytic efficiency was evaluated by studying the degradation profiles of alkylphenols using gas chromatography-flame ionization detector (GC-FID). It was found that the synthesized TiO2-G composites exhibit enhanced photocatalytic efficiencies as compared to pristine TiO2. The presence of graphene not only provides a large surface area support for the TiO2photocatalyst, but also stabilizes charge separation by trapping electrons transferred from TiO2, thereby hindering charge transfer and enhancing its photocatalytic efficiency.

Aqueous Ferrofluid of Citric Acid Coated Magnetite Particles

2003 ◽  
Vol 789 ◽  
Author(s):  
A. Goodarzi ◽  
Y. Sahoo ◽  
M. T. Swihart ◽  
P. N. Prasad
Keyword(s):  
Citric Acid ◽  
Photoelectron Spectroscopy ◽  
Quantum Interference ◽  
Fluorescent Dyes ◽  
Aqueous Suspension ◽  
Medical Diagnostics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Magnetite Particles

ABSTRACTMagnetic nanoparticles have found application in medical diagnostics such as magnetic resonance imaging and therapies such as cancer treatment. In these applications, it is imperative to have a biocompatible solvent such as water at optimum pH for possible bio-ingestion. In the present work, a synthetic methodology has been developed to get a well-dispersed and homogeneous aqueous suspension of Fe3O4 nanoparticles in the size range of 8–10 nm. The surface functionalization of the particles is provided by citric acid. The particles have been characterized using transmission electron microscopy, magnetization measurements with a superconducting quantum interference device, FTIR spectroscopy (for surfactant binding sites), thermogravimetric studies (for strength of surfactant binding), and x-ray photoelectron spectroscopy and x-ray diffraction (for composition and phase information). The carboxylate functionality on the surface provides an avenue for further surface modification with fluorescent dyes, hormone linkers etc for possible cell-binding, bioimaging, tracking, and targeting.

scholarly journals Oxalic Acid-Assisted Hydrothermal Synthesis and Luminescent of Hexagonal NaYF4:Ln3+ (Ln = Sm, Eu, Yb/Er) Micro/Nanoplates

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Feng Tao ◽  
Zhishun Shen ◽  
Zhijun Wang ◽  
Da Shu ◽  
Qi Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Oxalic Acid ◽  
Molar Ratio ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Display Systems

Hexagonal NaYF4:Ln3+ micro/nanoplates were successfully synthesized via a hydrothermal method using oxalic acid as a shape modifier. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) have been used to study the morphologies and crystal structure of the products. The effects of the pH values and the molar ratio of oxalic acid to NaOH on the crystal growth have been investigated in detail. The time-dependent experiments have been conducted to investigate the morphology evolution process, and based on the results, a possible growth mechanism was proposed. The photoluminescence properties of 5 mol% Eu3+ and 3 mol% Sm3+ doped NaYF4 and 20 mol% Yb3+/2 mol% Er3+ codoped NaYF4 micro/nanoplates were investigated. The experimental results showed that NaYF4:Ln3+ micro/nanoplates have excellent luminescence and can be potential application in the field of light display systems, lasers, and optoelectronic devices.

Research on the Microstructure and Mechanical Properties of Spray-Deposited 8009 Heat Resistant Aluminum Alloy

2014 ◽  
Vol 543-547 ◽  
pp. 3733-3736
Author(s):  
Rong Hua Zhang ◽  
Biao Wu ◽  
Xiao Ping Zheng
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Tensile Tests ◽  
Test Results ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Resistant ◽  
Microstructure And Mechanical Properties ◽  
Transmission Electron

In this study, 8009 heat resistant aluminum alloy was synthesized by the spray atomization and deposition technique. The microstructure and mechanical properties of the alloy were studied using transmission electron microscopy, X-ray diffraction, and tensile tests. The secondary phases in the microstructure of the spray-deposited alloy were examined. The tensile test results indicate that the spray-deposited 8009 alloy both at room and elevated temperature displays superior tensile strength due to the presence of the thermally stable Al12(Fe,V)3Si particles.

Antimony-Doped SnO2 Nanoparticles with Controlled Doping Level via Nonaqueous Sol-Gel Procedure

2013 ◽  
Vol 745-746 ◽  
pp. 685-689
Author(s):  
Jun Yan Wu ◽  
Fei Chen ◽  
Qiang Shen ◽  
Lian Meng Zhang
Keyword(s):  
Citric Acid ◽  
Photoelectron Spectroscopy ◽  
Doping Level ◽  
Sol Gel ◽  
Processing Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Adsorption Desorption ◽  
Controlled Doping

Antimony-doped tin oxide (ATO) nanoparticles with controlled doping level were prepared by a nonaqueous solution route, using alcohol as the solvent, citric acid as an agent, tin (IV) tetrachloride as tin source and antimony (III) chlorideas as antimony sources. As-synthesized samples were characterized by Thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), transmission electron micrographs (TEM), N2 adsorption-desorption isotherms, and X-ray photoelectron spectroscopy (XPS). The results showed that the content of citric acid was the most important processing parameter which was largely governing the reaction course and the complete incorporation of Sb. When the citric acid to metal mol ratio was 2, the particles were the highly crystallized ATO nanoparticles of about 20nm and the Sb atoms were indeed incorporated into the SnO2 crystal structure (cassiterite SnO2).

EFFECT OF pH ON ZnS NANOCRYSTALLINE THIN FILM EMBEDDED IN A POLYVINYL ALCOHOL MATRIX

2010 ◽  
Vol 24 (29) ◽  
pp. 5663-5673 ◽  
Author(s):  
J. P. BORAH ◽  
J. BARMAN ◽  
K. C. SARMA
Keyword(s):  
Electron Microscopy ◽  
Polyvinyl Alcohol ◽  
Ph Value ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
Nanocrystalline Thin Film ◽  
Transmission Electron ◽  
Uv Visible ◽  
Compositional Characterization

Polyvinyl alcohol (PVA) has been used as a matrix to synthesize ZnS / PVA nanocomposite film on glass substrate by chemical method. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Scanning electron microscopy (SEM) has been used for structural, morphological and compositional characterization. Optical properties have been studied by UV-Visible spectrophotometry and photoluminescence (PL) spectroscopy. Changing pH value from 4.8 to 0.8 decreases the particle size and correspondingly increases the band gap. The PL emission intensity also increases by decreasing the pH values.

Optical and photocatalytic properties of photoactive paper with polycrystalline TiO2 nanopigment for optimal product design

TAPPI Journal ◽  
2012 ◽  
Vol 11 (5) ◽  
pp. 33-38 ◽  
Author(s):  
SEONGHYUK KO ◽  
PAUL D. FLEMING ◽  
MARGARET JOYCE ◽  
PNINA ARI-GUR
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gas Chromatography ◽  
Titanium Dioxide ◽  
Optical Properties ◽  
Photocatalytic Activity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Optimal Product Design

We investigated the effect of the crystalline phases of titanium dioxide nanopigment to optimize the optical properties and photocatalytic activity for synthesizing a photoactive paper. Six different ratios of anatase to rutile were prepared. Phase change and particle size were characterized using X-ray diffraction and transmission electron microscopy. Optical properties including opacity and brightness were tested. Photocatalytic activity was evaluated by measuring toluene decomposition, using gas chromatography. A specific ratio between two different crystallites of titanium dioxide showed relatively better optical and photoactive properties. The optimal anatase-to-rutile ratio was found to be 0.52:0.48.

Effects of Acidic Amino Acids on Hydroxyapatite Morphology

2007 ◽  
Vol 336-338 ◽  
pp. 2096-2099 ◽  
Author(s):  
Wei Min Gao ◽  
Cheng Xiang Ruan ◽  
Yun Fa Chen
Keyword(s):  
Amino Acids ◽  
Aspartic Acid ◽  
Crystal Surface ◽  
Hydroxyapatite Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
Acidic Amino Acids ◽  
Transmission Electron ◽  
The Difference

Hydroxyapatite nanoparticles were synthesized in the presence of two kinds of acidic amino acids in order to investigate the effects of acidic amino acids on the morphology of hydroxyapatite obtained by homogeneous precipitation and hydrothermal treating. The results of X-ray diffraction analysis and microphotographs of transmission electron microscope showed that the morphology of hydroxyapatite nanoparticles changed significantly only with aspartic acid. Hydroxyapatite synthesized with aspartic acid showed smooth flake-like morphology at pH= 11 and flake-like morphology with stripes at pH= 8. However, hydroxyapatite synthesized in the present of glutamic acid showed rod-like morphology at both pH values. Variation in the morphology of nanoparticles could be consistent with the difference in the affinity of amino acids binding at the hydroxyapatite crystal surface. The adsorption process was revealed by computer simulation of molecular mechanics using energy minimizing method.

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