scholarly journals REVERSE MICROEMULSION OF IGEPAL Co-720 SYSTEM AS MICROREACTOR FOR CdS SYNTHESIS

2016 ◽  
Vol 10 (2) ◽  
pp. 157
Author(s):  
Fitria Rahmawati ◽  
Indah Rizki Fitriani ◽  
Abu Masykur
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Particle Diameter ◽  
Weight Ratio ◽  
Average Diameter ◽  
Reverse Microemulsion ◽  
X Ray Diffraction ◽  
Regular Form ◽  
Gap Energy ◽  
Hydrophilic Lipophilic Balance

<p>A Research on CdS synthesis in reverse microemulsion of Igepal CO-720 system has been conducted at various weight ratio of water to surfactant. Igepal CO-720 naturally forms  oil  in  water  (o/w)  emulsion  type  due  to  its  high  HLB  (Hydrophilic -Lipophilic Balance)  value.  Therefore,  in  this  research  the  Igepal  CO-720  system  was  inversed  into water  in  oil  (w/o)  system  before  it  was  used  as  microreactor  for  CdS  synthesis.  As comparison,  a  system  of  AOT  (Aerosol  OT;  sodium  bis (2-ethylhexyl)  sulfosuccinate) which  is  naturally  w/o  system  was  also  used  as  microreactor  for  CdS  synthesis.  The prepared  CdS  was  analyzed  by  X-ray  diffraction  for  crystal  identification,  scanning electron microscope for morphological analysis, UV-Vis for absorption edge determination and  photoelectrochemical  testing  for  photoactivity.  The  results  show that the  Igepal  CO -720  system can  be  inverted  into  w/o  system  and  can  be  used  as  microreactor  for  CdS synthesis. The prepared CdS is in nanosize with the average diameter of 2.517  ±  0.014 nm and  the  average  gap  energy  of  3.805  ±  0.178  eV.  The  prepared  CdS  in  Igepal  CO-720 system has less regular form in comparison with morphology of the prepared CdS in AOT system. As the ω  values decreases the particle diameter decreases, the gap energy increases and the %  IPCE increases. It indicates that high surfactant concentration allows small size micelles  formation  and  produced  smaller  CdS  particle  that  has  high  surface  area  and therefore  provide  higher  photocatalytic  activity  which  was  indicated  by  high  value  of  its % IPCE.</p>

scholarly journals REVERSE MICROEMULSION OF IGEPAL Co-720 SYSTEM AS MICROREACTOR FOR CdS SYNTHESIS

2016 ◽  
Vol 10 (2) ◽  
pp. 157
Author(s):  
Fitria Rahmawati ◽  
Indah Rizki Fitriani ◽  
Abu Masykur
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Particle Diameter ◽  
Weight Ratio ◽  
Average Diameter ◽  
Reverse Microemulsion ◽  
X Ray Diffraction ◽  
Regular Form ◽  
Gap Energy ◽  
Hydrophilic Lipophilic Balance

<p>A Research on CdS synthesis in reverse microemulsion of Igepal CO-720 system has been conducted at various weight ratio of water to surfactant. Igepal CO-720 naturally forms  oil  in  water  (o/w)  emulsion  type  due  to  its  high  HLB  (Hydrophilic -Lipophilic Balance)  value.  Therefore,  in  this  research  the  Igepal  CO-720  system  was  inversed  into water  in  oil  (w/o)  system  before  it  was  used  as  microreactor  for  CdS  synthesis.  As comparison,  a  system  of  AOT  (Aerosol  OT;  sodium  bis (2-ethylhexyl)  sulfosuccinate) which  is  naturally  w/o  system  was  also  used  as  microreactor  for  CdS  synthesis.  The prepared  CdS  was  analyzed  by  X-ray  diffraction  for  crystal  identification,  scanning electron microscope for morphological analysis, UV-Vis for absorption edge determination and  photoelectrochemical  testing  for  photoactivity.  The  results  show that the  Igepal  CO -720  system can  be  inverted  into  w/o  system  and  can  be  used  as  microreactor  for  CdS synthesis. The prepared CdS is in nanosize with the average diameter of 2.517  ±  0.014 nm and  the  average  gap  energy  of  3.805  ±  0.178  eV.  The  prepared  CdS  in  Igepal  CO-720 system has less regular form in comparison with morphology of the prepared CdS in AOT system. As the ω  values decreases the particle diameter decreases, the gap energy increases and the %  IPCE increases. It indicates that high surfactant concentration allows small size micelles  formation  and  produced  smaller  CdS  particle  that  has  high  surface  area  and therefore  provide  higher  photocatalytic  activity  which  was  indicated  by  high  value  of  its % IPCE.</p>

scholarly journals Porous Graphene Composite Polymer Fibres

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 76
Author(s):  
Jubair Ahmed ◽  
Tanveer A. Tabish ◽  
Shaowei Zhang ◽  
Mohan Edirisinghe
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Single Layer ◽  
Average Diameter ◽  
High Rate ◽  
Single Layer Graphene ◽  
X Ray Diffraction ◽  
Porous Graphene ◽  
The Many ◽  
First Time

Since the isolation of graphene, there have been boundless pursuits to exploit the many superior properties that this material possesses; nearing the two-decade mark, progress has been made, but more is yet to be done for it to be truly exploited at a commercial scale. Porous graphene (PG) has recently been explored as a promising membrane material for polymer composite fibres. However, controlling the incorporation of high surface area PG into polymer fibres remain largely unexplored. Additionally, most polymer-graphene composites suffer from low production rates and yields. In this paper, graphene-loaded microfibres, which can be produced at a very high rate and yield have been formed with a carrier polymer, polycaprolactone. For the first time, PG has been incorporated into polymer matrices produced by a high-output manufacturing process and analysed via multiple techniques; scanning electron microscopy (SEM), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Raman spectra showed that single layer graphene structures were achieved, evidence for which was also backed up by the other techniques. Fibres with an average diameter ranging from 3–8 μm were produced with 3–5 wt% PG. Here, we show how PG can be easily processed into polymeric fibres, allowing for widespread use in electrical and ultrafiltration systems

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.

Surface Hardness Modify and Improve Wear Properties of EP\ NanoZrO2

2021 ◽  
Vol 19 (2) ◽  
pp. 77-82
Author(s):  
Fadhil K. Farhan ◽  
Aws Abbas Hussein ◽  
Ali Q. Tuama
Keyword(s):  
Wear Resistance ◽  
High Surface ◽  
Ceramic Powder ◽  
High Surface Area ◽  
Surface Hardness ◽  
Weight Ratio ◽  
Hardness Test ◽  
Wear Properties ◽  
Mechanical Mixing ◽  
Dioxide Powder

The liquid and mechanical mixing method was used in addition to ultrasound technology to prepare samples according to standard conditions. The percentage of cementing with ceramic powder was adopted from 1% to 4% as a weight ratio, and by using mixing drivers, nanocomposites were prepared depending on the theoretical density of the components. The velvet density was measured using Archimedes' method, and the results showed a successive improvement and increase in density with the weight ratio of addition. The results of the particulate hardness test showed a significant improvement in the results of the prepared nanostructures compared to the base sample (pure epoxy). With regard to the properties of wear resistance (wear modulus) using the screw-on-disk method, the cemented samples showed a higher wear resistance compared to the base sample. The results were interpreted based on the values of density and hardness in addition to the properties possessed by the ceramic powder of high surface area and average granular size of 32 nanometers through scanning electron microscopy. In this work, nanostructures based on (a polymer) supported with nanoscale zirconium dioxide powder were developed.

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 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.

scholarly journals Measurement of density and wetness in snow using time-domain reflectometry

1998 ◽  
Vol 26 ◽  
pp. 69-72 ◽  
Author(s):  
Martin Schneebeli ◽  
Cécile Coléou ◽  
François Touvier ◽  
Bernard Lesaffre
Keyword(s):  
Time Domain ◽  
High Surface ◽  
High Surface Area ◽  
Weight Ratio ◽  
Time Domain Reflectometry ◽  
Soil Physics ◽  
Snow Density ◽  
Intense Solar Radiation ◽  
Air Pockets

Time-domain reflectometry (TDR) is widely used in soil physics to determine water content. Existing equipment and methods ran be adapted to measurements of snow wetness. The main advantages compared to other methods are flexibility in constructing sensors, minimal influence on snow cover during measurements and sensors can be multiplexed. We developed sensors suitable for continuous and non-continuous measurements of snow wetness and density, measured the apparent permittivity in different snow densities and snow types, and compared the measurements to existing mixing formulas for mixtures of snow and air. In dry snow, density was measured from 110 to 470 kg m−3. The residual error is 14 kg m −3 and the 95% confidence interval of our model is 3 kg m−3. To measure snow density and wetness continuously suitable sensors have been constructed. Their small size and high surface area to weight ratio minimizes their movement in the snowpack, except when they are exposed to intense solar radiation. Results show that changes in dry-snow density of less than 5 kgm−3 can be detected. Infiltration of even small amounts of water clearly shows up in the permittivity. At the surface of the snowpack, problems occur due to the formation of air pockets around the sensors during long-term measurements.

scholarly journals An openwork like structures of polylactide – manufacturing and properties

2018 ◽  
Vol 44 ◽  
pp. 00165 ◽  
Author(s):  
Karolina Sobczyk ◽  
Karol Leluk
Keyword(s):  
Lactic Acid ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Weight Ratio ◽  
Electrospinning Process ◽  
Poly Lactic Acid ◽  
Process Conditions ◽  
Fiber Morphology

Poly(lactic acid) electrospinning tests were carried out under various process conditions. Openwork structures with a high surface area to weight ratio have been obtained. Changing the parameters of the PLA electrospinning process resulted in products with different fiber morphology.

scholarly journals Measurement of density and wetness in snow using time-domain reflectometry

1998 ◽  
Vol 26 ◽  
pp. 69-72 ◽  
Author(s):  
Martin Schneebeli ◽  
Cécile Coléou ◽  
François Touvier ◽  
Bernard Lesaffre
Keyword(s):  
Time Domain ◽  
High Surface ◽  
High Surface Area ◽  
Weight Ratio ◽  
Time Domain Reflectometry ◽  
Soil Physics ◽  
Snow Density ◽  
Intense Solar Radiation ◽  
Air Pockets

Time-domain reflectometry (TDR) is widely used in soil physics to determine water content. Existing equipment and methods ran be adapted to measurements of snow wetness. The main advantages compared to other methods are flexibility in constructing sensors, minimal influence on snow cover during measurements and sensors can be multiplexed. We developed sensors suitable for continuous and non-continuous measurements of snow wetness and density, measured the apparent permittivity in different snow densities and snow types, and compared the measurements to existing mixing formulas for mixtures of snow and air. In dry snow, density was measured from 110 to 470 kg m−3. The residual error is 14 kg m −3 and the 95% confidence interval of our model is 3 kg m−3. To measure snow density and wetness continuously suitable sensors have been constructed. Their small size and high surface area to weight ratio minimizes their movement in the snowpack, except when they are exposed to intense solar radiation. Results show that changes in dry-snow density of less than 5 kgm−3 can be detected. Infiltration of even small amounts of water clearly shows up in the permittivity. At the surface of the snowpack, problems occur due to the formation of air pockets around the sensors during long-term measurements.

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