Electrical and Structural Properties of HDPE/MWCNT/PE-g-MAH Nanocomposites Prepared Using Solution Mixing and Hot Compaction Two-Step Approach

2021 ◽  
Vol 17 ◽  
Author(s):  
Mahmoud Al-Hussein ◽  
Ali Jaffal ◽  
Rund Abu-Zuryak
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Morphological Characterization ◽  
X Ray Diffraction ◽  
Positive Role ◽  
Agent Based ◽  
Multi Wall Carbon Nanotubes ◽  
Hot Compaction ◽  
Compatibilizer Agent

Background: MWCNTs tend to form agglomerates in nonpolar polymers due to their small size and high surface area. A promising approach to facilitate their dispersion within the polymeric matrix is based on employing a compatibilizer agent. Objective: The current study aimed to investigate the effect of a compatibilizer agent based on maleic anhydride grafted HDPE (PE-g-MAH) on the electrical and morphology properties of high density polyethylene/multi wall carbon nanotubes nanocomposites (HDPE/MWCNT/PE-g-MAH) prepared by solution mixing and hot compaction two-step approach. Methods: A two-step approach based on solvent mixing and hot compaction was used to prepare nanocomposites of HDPE/MWCNT/PE-g-MAH with different MWCNTs and PE-g-MAH contents. The electrical, morphology and HDPE crystalline structure properties of the nanocomposites were characterized by impedance spectroscopy, high resolution field emmision scanning electron microscopy and X-ray diffraction, respectively. Results: The results confirm the positive role of the PE-g-MAH compatibilizer in enhancing the dispersion of the MWCNTs and in turn the formation of more conductive pathways at low MWCNTs content in the nanocomposites. Adding 2 wt% of the compatibilizer to the nanocomposite of 1 wt% MWCNTs increases the electrical conductivity more than three orders of magnitude. Increasing the MWCNTs concentration more than 1 wt% leads to a limited enhancement in conductivity of the nanocomposite prepared using 2 wt% of PE-g-MAH compatibilizer. Meanwhile, the morphological characterization revealed that the limited increase in conductivity of nanocomposites with only 1 wt% compatibilizer is related to a substantial increase in the HDPE crystallinity (from 14.8 to 43.9%) induced by the enhanced nucleating effect of the dispersed MWCNTs. The excess HDPE crystalline regions suppress the formation of effective MWCNTs conducting pathways due to their confinement into smaller inter-crystallite regions in the nanocomposite. Conclusion: Therefore, a balanced role of the compatibilizer between dispersion of the MWCNTs and the nucleation of more HDPE crystallites has to be achieved by carefully selecting the compatibilizer type and concentration.

scholarly journals Synthesis of Wollastonite Powders by Combustion Method: Role of Amount of Fuel

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Imarally V. de S. R. Nascimento ◽  
Willams T. Barbosa ◽  
Raúl G. Carrodeguas ◽  
Marcus V. L. Fook ◽  
Miguel A. Rodríguez
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Combustion Process ◽  
Calcium Nitrate ◽  
Combustion Method ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Solution Combustion

The objective of this work has been the synthesis of wollastonite by solution combustion method. The novelty of this work has been obtaining the crystalline phase without the need of thermal treatments after the synthesis. For this purpose, urea was used as fuel. Calcium nitrate was selected as a source of calcium and colloidal silica served as a source of silicon. The effect of the amount of fuel on the combustion process was investigated. Temperature of the combustion reaction was followed by digital pyrometry. The obtained products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and specific surface area. The results showed that the combustion synthesis provides nanostructured powders characterized by a high surface area. When excess of urea was used, wollastonite-2M was obtained with a submicronic structure.

scholarly journals Single and Dual Metal Oxides as Promising Supports for Carbon Monoxide Removal from an Actual Syngas: The Crucial Role of Support on the Selectivity of the Au–Cu System

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 852 ◽  
Author(s):  
Bernay Cifuentes ◽  
Felipe Bustamante ◽  
Martha Cobo
Keyword(s):  
Metal Oxides ◽  
High Surface ◽  
High Surface Area ◽  
Carbon Deposits ◽  
Promising Strategy ◽  
Cu Catalysts ◽  
Dual Metal ◽  
Effect Of The Support ◽  
Lower Capacity

A catalytic screening was performed to determine the effect of the support on the performance of an Au–Cu based system for the removal of CO from an actual syngas. First, a syngas was obtained from reforming of ethanol. Then, the reformer outlet was connected to a second reactor, where Au–Cu catalysts supported on several single and dual metal oxides (i.e., CeO2, SiO2, ZrO2, Al2O3, La2O3, Fe2O3, CeO2-SiO2, CeO2-ZrO2, and CeO2-Al2O3) were evaluated. AuCu/CeO2 was the most active catalyst due to an elevated oxygen mobility over the surface, promoting CO2 formation from adsorption of C–O* and OH− intermediates on Au0 and CuO species. However, its lower capacity to release the surface oxygen contributes to the generation of stable carbon deposits, which lead to its rapid deactivation. On the other hand, AuCu/CeO2-SiO2 was more stable due to its high surface area and lower formation of formate and carbonate intermediates, mitigating carbon deposits. Therefore, use of dual supports could be a promising strategy to overcome the low stability of AuCu/CeO2. The results of this research are a contribution to integrated production and purification of H2 in a compact system.

scholarly journals Attached β-cyclodextrin/γ-(2,3-epoxypropoxy) propyl trimethoxysilane to graphene oxide and its application in copper removal

2017 ◽  
Vol 75 (10) ◽  
pp. 2403-2411 ◽  
Author(s):  
Zongxue Yu ◽  
Qi Chen ◽  
Liang Lv ◽  
Yang Pan ◽  
Guangyong Zeng ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
High Surface ◽  
High Surface Area ◽  
Esterification Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cavity Structure ◽  
Optimum Ph ◽  
Exchange Adsorption ◽  
Langmuir Isotherm Model

The environmental applications of graphene oxide and β-cyclodextrin (β-CD) have attracted great attention since their first discovery. Novel nanocomposites were successfully prepared by using an esterification reaction between β-cyclodextrin/γ-(2,3-epoxypropoxy) propyl trimethoxysilane grafted graphene oxide (β-CD/GPTMS/GO). The β-CD/GPTMS/GO nanocomposites were used to remove the Cu2+ from aqueous solutions. The characteristics of β-CD/GPTMS/GO were detected by scanning electron microscopy (SEM), Fourier transform infrared, X-ray diffraction (XRD), thermogravimetric analysis (TG) and energy dispersive X-ray (EDX). The dispersibility of graphene oxide was excellent due to the addition of β-CD. The adsorption isotherms data obtained at the optimum pH 7 were fitted by Langmuir isotherm model. The excellent adsorption properties of β-CD/GPTMS/GO for Cu2+ ions could be attributed to the apolar cavity structure of β-CD, the high surface area and abundant functional groups on the surface of GO. The adsorption patterns of β-CD/GPTMS/GO were electrostatic attraction, formation of host-guest inclusion complexes and the ion exchange adsorption. The efficient adsorption of β-CD/GPTMS/GO for Cu2+ ions suggested that these novel nanocomposites may be ideal candidates for removing other cation pollutants from waste water.

Biological weathering in soil: the role of symbiotic root-associated fungi biosensing minerals and directing photosynthate-energy into grain-scale mineral weathering

2008 ◽  
Vol 72 (1) ◽  
pp. 85-89 ◽  
Author(s):  
J. R. Leake ◽  
A. L. Duran ◽  
K. E. Hardy ◽  
I. Johnson ◽  
D. J. Beerling ◽  
...  
Keyword(s):  
Carbon Allocation ◽  
High Surface ◽  
Turgor Pressure ◽  
High Surface Area ◽  
Volume Ratio ◽  
Mineral Weathering ◽  
Mycorrhizal Associations ◽  
P Content ◽  
Biological Weathering

AbstractBiological weathering is a function of biotic energy expenditure. Growth and metabolism of organisms generates acids and chelators, selectively absorbs nutrient ions, and applies turgor pressure and other physical forces which, in concert, chemically and physically alter minerals. In unsaturated soil environments, plant roots normally form symbiotic mycorrhizal associations with fungi. The plants provide photosynthate-carbohydrate-energy to the fungi in return for nutrients absorbed from the soil and released from minerals. In ectomycorrhiza, one of the two major types of mycorrhiza of trees, roots are sheathed in fungus, and 15—30% of the net photosynthate of the plants passes through these fungi into the soil and virtually all of the water and nutrients taken up by the plants are supplied through the fungi. Here we show that ectomycorrhizal fungi actively forage for minerals and act as biosensors that discriminate between different grain sizes (53—90 μm, 500—1000 μm) and different minerals (apatite, biotite, quartz) to favour grains with a high surface-area to volume ratio and minerals with the highest P content. Growth and carbon allocation of the fungi is preferentially directed to intensively interact with these selected minerals to maximize resource foraging.

Synthesis and Photocatalytic Properties of the Bi2MoO6 and Bi2WO6 Photocatalysts

2018 ◽  
Vol 768 ◽  
pp. 218-223
Author(s):  
Juan Xia ◽  
Lin Zhang ◽  
Qi Wang
Keyword(s):  
Light Absorption ◽  
Hydrothermal Reaction ◽  
Organic Dyes ◽  
High Surface ◽  
Diffuse Reflectance Spectrum ◽  
High Surface Area ◽  
Photocatalytic Properties ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
One Pot

Two different Bi-based semiconductor photocatalysts Bi2MoO6 and Bi2WO6 were synthesized by a simple one-pot hydrothermal reaction at 453 K for 10 h. The properties of the photocatalysts, including structures, morphology, light-absorption band and photoluminescence, etc were characterized by X-ray diffraction, scanning electron microscopy, UV-Vis diffuse reflectance spectrum and fluorescence spectrum. Further, their photocatalytic properties were compared by the degradation of two different organic dyes: Rhodamine B and methylene blue. It is important to note that the Bi2WO6 nanoplate structure exhibited better photocatalytic activity than the Bi2MoO6 nanowires aggregates due to its high surface area, higher light absorption and lower recombination of electron-hole pairs.

scholarly journals The Role of Surface Hydroxylation, Lattice Vacancies and Bond Covalency in the Electrochemical Oxidation of Water (OER) on Ni-Depleted Iridium Oxide Catalysts

2020 ◽  
Vol 234 (5) ◽  
pp. 787-812 ◽  
Author(s):  
Hong Nhan Nong ◽  
Hoang Phi Tran ◽  
Camillo Spöri ◽  
Malte Klingenhof ◽  
Lorenz Frevel ◽  
...  
Keyword(s):  
Metal Oxide ◽  
High Surface ◽  
High Surface Area ◽  
Oxide Shell ◽  
Mixed Metal Oxide ◽  
Support Materials ◽  
Oxide Support ◽  
Rich Alloy ◽  
Surface Hydroxylation

AbstractThe usage of iridium as an oxygen-evolution-reaction (OER) electrocatalyst requires very high atom efficiencies paired with high activity and stability. Our efforts during the past 6 years in the Priority Program 1613 funded by the Deutsche Forschungsgemeinschaft (DFG) were focused to mitigate the molecular origin of kinetic overpotentials of Ir-based OER catalysts and to design new materials to achieve that Ir-based catalysts are more atom and energy efficient, as well as stable. Approaches involved are: (1) use of bimetallic mixed metal oxide materials where Ir is combined with cheaper transition metals as starting materials, (2) use of dealloying concepts of nanometer sized core-shell particle with a thin noble metal oxide shell combined with a hollow or cheap transition metal-rich alloy core, and (3) use of corrosion-resistant high-surface-area oxide support materials. In this mini review, we have highlighted selected advances in our understanding of Ir–Ni bimetallic oxide electrocatalysts for the OER in acidic environments.

scholarly journals Promoting Li/MgO Catalyst with Molybdenum Oxide for Oxidative Conversion of n-Hexane

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 354 ◽  
Author(s):  
Cassia Boyadjian ◽  
Leon Lefferts
Keyword(s):  
Raman Spectroscopy ◽  
High Surface ◽  
High Surface Area ◽  
Deep Oxidation ◽  
Oxidative Conversion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Anionic Species ◽  
Dehydrogenation Reactions ◽  
Lithium Molybdate

In this work, molybdena-promoted Li/MgO is studied as a catalyst for the oxidative conversion of n-hexane. The structure of the catalysts is investigated with X-ray Diffraction (XRD) and Raman spectroscopy. The MoO3/Li/MgO catalyst contains three types of molybdena-containing species, the presence of which depend on molybdena loading. At low Mo/Li ratios (i) isolated dispersed [MoO4]2− anionic species are observed. At high Mo/Li ratios, the formation of crystalline lithium molybdate phases such as (ii) monomeric Li2MoO4 and tentatively (iii) polymeric Li2Mo4O13 are concluded. The presence of these lithium molybdates diminishes the formation of Li2CO3 in the catalyst. Subsequently, the catalyst maintains high surface area and stability with time-on-stream during oxidative conversion. Molybdena loading as low as 0.5 wt % is sufficient to induce these improvements, maintaining the non-redox characteristics of the catalyst, whereas higher loadings enhance deep oxidation and oxidative dehydrogenation reactions. Promoting a Li/MgO catalyst with 0.5 wt % MoO3 is thus efficient for selective conversion of n-hexane to alkenes, giving alkene yield up to 24% as well as good stability.

Synthesis and Characterization of Nanocrystalline Hydroxyapatite Powder

2015 ◽  
Vol 1087 ◽  
pp. 142-146 ◽  
Author(s):  
Rosli Asmawi ◽  
Mohd Halim Irwan Ibrahim ◽  
Azriszul Mohd Amin ◽  
Najwa Mustapha ◽  
Iis Sopyan
Keyword(s):  
Particle Size ◽  
Calcium Phosphate ◽  
High Surface ◽  
High Surface Area ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Heating Process ◽  
X Ray Diffraction ◽  
Nanocrystalline Hydroxyapatite

Nanocrystalline hydroxyapatite (HA) powder was synthesized by a simple heating process involving simple chemical reaction. The characterization of the produced powder showed that the powder is nanosize with particle in the range of 30-70 mm in diameter and almost evenly spherical in shape. The powder also has a high surface area of 43.16 m2/g. Field Emission Scanning Electron Microscopy (FESEM) observation showed the crystallite and particle size become bigger with an increment of calcination temperature, indicating increasing of crystallinity.. FESEM observation showed the particle size become bigger with an increment of calcinations temperature. It is in agreement with the crystallite size analysis, obtained by Scherer’s formula and particle size analysis, measured by nanoSizer. X-ray Diffraction (XRD) and Fourier Transform Infra Red Spectroscopy (FTIR) analyses exhibited the same result, where HA phase was clearly observed at at various temperatures up to 600 ̊C. However, at temperature more than 600 ̊C, Tri calcium phosphate (TCP) phase appeared suppressing the HA phase, producing biphasic calcium phosphate.

Graphene-based Nanomaterials for Fabrication of ‘Pesticide’ Electrochemical Sensors

2020 ◽  
Vol 3 (1) ◽  
pp. 26-40
Author(s):  
Manorama Singh ◽  
Smita R. Bhardiya ◽  
Fooleswar Verma ◽  
Vijai K. Rai ◽  
Ankita Rai
Keyword(s):  
Electrochemical Sensors ◽  
Hybrid Composites ◽  
High Surface ◽  
High Surface Area ◽  
High Sensitivity ◽  
Sensor Technology ◽  
Hybrid Functional ◽  
Suitable Material ◽  
Functional Composites

At present, graphene is one of the most up-to-date materials and it can be applied for various energy conversion devices and sensor technology. In this review article, our main focus is to summarize the role of graphene and its modified surface leading to develop hybrid nanomaterials and its applications in fabrication of pesticide sensor. Graphene based materials demonstrate exclusive electrochemical and optical properties as well as compatibility to absorb a variety of bio-molecules through π-π stacking interaction and/or electrostatics interaction, which make them ideal material to be employed in sensor application. The role of graphene is very crucial in preparing different unique and desirable hybrid functional composites along with nanoparticles, redox mediators, conducting polymers etc. to improve the performance of the sensors. Therefore, they can be easily used as a suitable material applying in fabrication of electrochemical sensors/ biosensors for the detection of organophosphorous and carbamate pesticides. A number of most recent reported works were discussed in which graphene-based hybrid composites show high sensitivity, good catalytic activity, selectivity towards the determination of pesticide either enzymatically or nonenzymatically. The properties of graphene (exceptional charge transport, thermal, optical, mechanical, high surface area, large pore volume and size, an opened ordered structure) play an important role in pesticide detection.

scholarly journals Amorphous Mo5O14-Type/Carbon Nanocomposite with Enhanced Electrochemical Capability for Lithium-Ion Batteries

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 8 ◽  
Author(s):  
Ahmed M. Hashem ◽  
Ashraf E. Abdel-Ghany ◽  
Rasha S. El-Tawil ◽  
Sylvio Indris ◽  
Helmut Ehrenberg ◽  
...  
Keyword(s):  
Oxygen Deficiency ◽  
High Surface ◽  
High Surface Area ◽  
Lithium Ion ◽  
Carbon Matrix ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Thermal Gravimetry ◽  
Type C ◽  
Carbon Nanocomposite

An amorphous MomO3m−1/carbon nanocomposite (m ≈ 5) is fabricated from a citrate–gel precursor heated at moderate temperature (500 °C) in inert (argon) atmosphere. The as-prepared Mo5O14-type/C material is compared to α-MoO3 synthesized from the same precursor in air. The morphology and microstructure of the as-prepared samples are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman scattering (RS) spectroscopy. Thermal gravimetry and elemental analysis indicate the presence of 25.8 ± 0.2% of carbon in the composite. The SEM images show that Mo5O14 is immersed inside a honeycomb-like carbon matrix providing high surface area. The RS spectrum of Mo5O14/C demonstrates an oxygen deficiency in the molybdenum oxide and the presence of a partially graphitized carbon. Outstanding improvement in electrochemical performance is obtained for the Mo5O14 encapsulated by carbon in comparison with the carbon-free MoO3.

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