The Transformation of Green Rusts on the Surface of Portland Cement Hydration Materials

2022 ◽  
Vol 905 ◽  
pp. 344-349
Author(s):  
Bo Jiang
Keyword(s):  
Iron Oxide ◽  
Portland Cement ◽  
Cement Hydration ◽  
Low Cost ◽  
Iron Modification ◽  
Carrier Materials ◽  
Minor Part ◽  
Green Rusts ◽  
Co Precipitation ◽  
A Minor

Ordinary Portland cement (OPC) is widely used building material, and its hydration products can be recycling as low-cost absorbents. The loading of iron oxide is helpful to further improve their adsorption performance. In view of the fact that green rusts are frequently occurrence intermediate products in the co-precipitation of iron salt and prone to be oxidized into stable iron minerals. This study simulated co-precipitation to carry out iron-modification on hydration OPC. The results demonstrate that as the carrier materials, hydration OPC behaves excellent affinity with green rusts. Under the conditions of high temperature (70 oC) and high alklinity (pH=11), green rusts mainly transformed into feroxydrate, and a minor part are into magnetite. The enrichment and transformation of green rust can be regarded as an efficient approach for immobilization of iron oxide (oxyhydroxide).

Biological activity of gum Arabic-coated ferrous oxide nanoparticles

2021 ◽  
pp. 2150411
Author(s):  
Rania Hasan Huseen ◽  
Ali A. Taha ◽  
Ihab Q. Ali ◽  
Oday Mahmmod Abdulhusein ◽  
Selma M. H. Al-Jawad
Keyword(s):  
Iron Oxide ◽  
Cell Line ◽  
Biological Activities ◽  
Low Cost ◽  
Gum Arabic ◽  
Precipitation Method ◽  
Oxide Nanoparticles ◽  
Electron Microscopic ◽  
Co Precipitation ◽  
Mcf 7

In this study, iron oxide nanoparticles (NPs) had been prepared by co-precipitation method. In order to reduce their toxicity and increase stability, prepared iron oxide was coated with gum Arabic. Gum Arabic is preferred over synthetic materials due to their non-toxicity, low cost and availability. Characterization of coated and non-coated iron oxide NPs had been performed by spectrophotometer, Fourier transfer infra-red spectrophotometer (FTIR), Zeta potential, X-ray diffraction (XRD) and field emission scanning electron microscopic (FE-SEM). The fabricated nanoparticles appeared purity and crystalline nature by XRD, with diameter average of 27.01 nm and 55.12 nm for iron oxide NPs and iron oxide NPs coated with gum Arabic, respectively. On the other hand, four biological activities of coated and non-coated iron oxide had been investigated. High removal of methylene blue pollutant dye (46%) was observed with iron oxide NPs, while removal percentage was 22.6 performed by iron oxide NPs coated with gum Arabic within 72 h. Iron oxide NPs revealed high inhibition zones of 27.5 nm and 30 mm, at 1000 [Formula: see text]g/ml, against S. aureus and E. coli, respectively, while coated iron oxide NPs with gum Arabic revealed low antibacterial activity against both examined bacteria even when used at 1000 [Formula: see text]g/ml. The hemolytic activity of prepared NPs had been determined. The hemolytic percentage was increased whenever concentrations of nanoparticles increased. Lower hemolytic percentages were 69.76 and 50.98 for iron oxide NPs and iron oxide NPs coated with gum Arabic were observed at a concentration of 250 [Formula: see text]g/ml. Finally, cytotoxic activity was estimated against MCF-7 cell line and normal cell line WRL68 by MTT assay. A decrease in MCF-7 viability to 65.1% was observed when 400 [Formula: see text]g/ml of iron oxide NPs was used, while WRL68 viability was 75.03%. Iron oxide NPs coated with gum Arabic revealed significant reduction in MCF-7 and WRL68 viability to 69.90% and 80.05%, respectively, when 400 [Formula: see text]g/ml of nanoparticles was applied.

Development of a Capacitor Probe to Detect Subsurface Deterioration in Concrete

1997 ◽  
Vol 503 ◽  
Author(s):  
B. K. Diefenderfer ◽  
I. L. Al-Qadi ◽  
J. J. Yoho ◽  
S. M. Riad ◽  
A. Loulizi
Keyword(s):  
Dielectric Constant ◽  
Portland Cement ◽  
Electromagnetic Waves ◽  
Low Cost ◽  
Complex Dielectric Constant ◽  
Life Cycle Costs ◽  
Parallel Plates ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Set Up

ABSTRACTPortland cement concrete (PCC) structures deteriorate with age and need to be maintained or replaced. Early detection of deterioration in PCC (e.g., alkali-silica reaction, freeze/thaw damage, or chloride presence) can lead to significant reductions in maintenance costs. However, it is often too late to perform low-cost preventative maintenance by the time deterioration becomes evident. By developing techniques that would enable civil engineers to evaluate PCC structures and detect deterioration at early stages (without causing further damage), optimization of life-cycle costs of the constructed facility and minimization of disturbance to the facility users can be achieved.Nondestructive evaluation (NDE) methods are potentially one of the most useful techniques ever developed for assessing constructed facilities. They are noninvasive and can be performed rapidly. Portland cement concrete can be nondestructively evaluated by electrically characterizing its complex dielectric constant. The real part of the dielectric constant depicts the velocity of electromagnetic waves in PCC. The imaginary part, termed the “loss factor,” describes the conductivity of PCC and the attenuation of electromagnetic waves.Dielectric properties of PCC have been investigated in a laboratory setting using a parallel plate capacitor operating in the frequency range of 0.1 to 40.1MIHz. This capacitor set-up consists of two horizontal-parallel plates with an adjustable separation for insertion of a dielectric specimen (PCC). While useful in research, this approach is not practical for field implementation. A new capacitor probe has been developed which consists of two plates, located within the same horizontal plane, for placement upon the specimen to be tested. Preliminary results show that this technique is feasible and results are promising; further testing and evaluation is currently underway.

THE ROLE OF ANTHROPONYMS IN THE SEMANTIC FIELD OF ARTISTIC WORKS

2019 ◽  
Vol 2019 (29) ◽  
pp. 66-77
Author(s):  
Lidiya Derbenyova
Keyword(s):  
Literary Work ◽  
Main Theme ◽  
Semantic Field ◽  
New Meanings ◽  
Minor Part ◽  
The One ◽  
A Minor ◽  
And Storage ◽  
Horizon Of Expectations

The article explores the role of antropoetonyms in the reader’s “horizon of expectation” formation. As a kind of “text in the text”, antropoetonyms are concentrating a large amount of information on a minor part of the text, reflecting the main theme of the work. As a “text” this class of poetonyms performs a number of functions: transmission and storage of information, generation of new meanings, the function of “cultural memory”, which explains the readers’ “horizon of expectations”. In analyzing the context of the literary work we should consider the function of antropoetonyms in vertical context (the link between artistic and other texts, and the groundwork system of culture), as well as in the context of the horizontal one (times’ connection realized in the communication chain from the word to the text; the author’s intention). In this aspect, the role of antropoetonyms in the structure of the literary text is extremely significant because antropoetonyms convey an associative nature, generating a complex mechanism of allusions. It’s an open fact that they always transmit information about the preceding text and suggest a double decoding. On the one hand, the recipient decodes this information, on the other – accepts this as a sort of hidden, “secret” sense.

EFFECT OF VISCOSITY MODIFIER ADMIXTURE ON PORTLAND CEMENT HYDRATION

2018 ◽  
Author(s):  
Stefan C. Figueiredo ◽  
Oğuzhan Çopuroğlu ◽  
Erik Schlangen
Keyword(s):  
Portland Cement ◽  
Cement Hydration ◽  
Viscosity Modifier ◽  
Portland Cement Hydration

Electrostatic effects on ionization equilibria: An MNDO study of proton and hydrogen transfer reactions of 4-fluorobutylamine

1990 ◽  
Vol 55 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Zdeněk Friedl ◽  
Stanislav Böhm
Keyword(s):  
Hydrogen Transfer ◽  
Substituent Effects ◽  
Radical Cations ◽  
Transfer Reactions ◽  
Protonated Forms ◽  
Minor Part ◽  
Bond Strengths ◽  
Ionization Equilibria ◽  
A Minor ◽  
Gas Phase Basicities

The relative enthalpies of proton transfer δ ΔH0and homolytic bond strengths δDH0(B-H+) were calculated by the MNDO method for the sp and ap conformers of 4-flurobutylamine. The data obtained, along with the experimental gas phase basicities, are compared with the values predicted by the electrostatic theory. It is shown that the substituent polar effects FD on the basicities of amines are predominantly due to interactions in their protonated forms (X-B-H+) and/or radical-cations (X-B+.), those in the neutral species (X-B) playing a minor part. A contribution, which is considerably more significant in the sp conformer than in the ap conformer, arises probably also from substituent effects on the homolytic bond strength DH0(B-H+.

scholarly journals Magnetic iron oxide/clay nanocomposites for adsorption and catalytic oxidation in water treatment applications

2020 ◽  
Vol 18 (1) ◽  
pp. 1148-1166
Author(s):  
Ganjar Fadillah ◽  
Septian Perwira Yudha ◽  
Suresh Sagadevan ◽  
Is Fatimah ◽  
Oki Muraza
Keyword(s):  
Iron Oxide ◽  
Water Treatment ◽  
Photocatalytic Oxidation ◽  
Low Cost ◽  
Synthesis Method ◽  
Chemical Oxidation ◽  
Magnetic Iron Oxide ◽  
Oxidation Processes ◽  
Recent Developments ◽  
Physical And Chemical

AbstractPhysical and chemical methods have been developed for water and wastewater treatments. Adsorption is an attractive method due to its simplicity and low cost, and it has been widely employed in industrial treatment. In advanced schemes, chemical oxidation and photocatalytic oxidation have been recognized as effective methods for wastewater-containing organic compounds. The use of magnetic iron oxide in these methods has received much attention. Magnetic iron oxide nanocomposite adsorbents have been recognized as favorable materials due to their stability, high adsorption capacities, and recoverability, compared to conventional sorbents. Magnetic iron oxide nanocomposites have also been reported to be effective in photocatalytic and chemical oxidation processes. The current review has presented recent developments in techniques using magnetic iron oxide nanocomposites for water treatment applications. The review highlights the synthesis method and compares modifications for adsorbent, photocatalytic oxidation, and chemical oxidation processes. Future prospects for the use of nanocomposites have been presented.

scholarly journals Preparation of Porous Hydroxyapatite Using Cetyl Trimethyl Ammonium Bromide as Surfactant for the Removal of Lead Ions from Aquatic Solutions

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1617
Author(s):  
Silviu-Adrian Predoi ◽  
Carmen Steluta Ciobanu ◽  
Mikael Motelica-Heino ◽  
Mariana Carmen Chifiriuc ◽  
Monica Luminita Badea ◽  
...  
Keyword(s):  
Cetyl Trimethyl Ammonium Bromide ◽  
Morphological Changes ◽  
Low Cost ◽  
Lead Ions ◽  
Ammonium Bromide ◽  
Porous Hydroxyapatite ◽  
X Ray ◽  
Composition And Structure ◽  
Cetyl Trimethyl Ammonium ◽  
Co Precipitation

In the present study, a new low-cost bioceramic nanocomposite based on porous hydroxyapatite (HAp) and cetyl trimethyl ammonium bromide (CTAB) as surfactant was successfully obtained by a simple chemical co-precipitation. The composition and structure of the HAp-CTAB were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) spectrometer, and N2 adsorption/desorption analysis. The capacity of HAp-CTAB nanocomposites to remove the lead ions from aqueous solutions was studied by adsorption batch experiments and proved by Langmuir and Freundlich models. The Pb2+ removal efficiency of HAp-CTAB biocomposite was also confirmed by non-destructive ultrasound studies. The cytotoxicity assays showed that the HAp-CTAB nanocomposites did not induce any significant morphological changes of HeLa cells after 24 h of incubation or other toxic effects. Taken together, our results suggests that the obtained porous HAp-CTAB powder could be used for the decontamination of water polluted with heavy metals, such as Pb2+.

scholarly journals Low-temperature combustion of methane over graphene templated Co3O4 defective-nanoplates

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dian Gong ◽  
Gaofeng Zeng
Keyword(s):  
Low Temperature ◽  
Transition Metal Oxides ◽  
Active Oxygen Species ◽  
Low Cost ◽  
Thermal Reduction ◽  
Low Temperature Combustion ◽  
Solid Catalysts ◽  
Intermittent Feeding ◽  
Co Precipitation ◽  
Catalytic Combustion Of Methane

AbstractTransition metal oxides are the potential catalysts to replace noble-metal based catalyst for the catalytic combustion of methane due to the tolerable reactivity and low cost. However, these catalysts are challenged by the low temperature reactivity. Herein, the surface defective Co3O4 nanoplates are realized through a facile co-precipitation and thermal reduction method with the association of GO. The resultant catalysts (CoGO50) demonstrate a superior low-temperature reactivity for the methane oxidation to CO2 and H2O in comparison with the common Co3O4 catalyst. The reliable stability of CoGO50 catalyst was proved by 80 h testing with intermittent feeding of water vapor. The experimental analysis demonstrates that the presence of a small amount of GO significantly affects the catalysts in surface valence state, active oxygen species and surface oxygen vacancies through reacting with the cobalt oxide as a reductant. Moreover, GO plays as 2D confine template to form smaller and thinner nanoplates. This work provides a facile method to control the surface properties of catalyst not only for Co3O4 based catalysts but also for wider solid catalysts.

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