scholarly journals THE INFLUENCE OF Si/Al MOLE RATIO OF PRECURSOR SOLUTION ON THE STRUCTURAL PROPERTIES OF MCM-41 FROM FLY ASH

2010 ◽  
Vol 3 (2) ◽  
pp. 126-134
Author(s):  
Sutarno Sutarno ◽  
Yateman Arryanto ◽  
Stefani Wigati
Keyword(s):  
Fly Ash ◽  
Structural Properties ◽  
Sodium Silicate ◽  
Precursor Solution ◽  
Ammonium Hydroxide ◽  
Pore Wall ◽  
Nitrogen Adsorption ◽  
Average Pore ◽  
Xrd Pattern ◽  
Mcm 41

The synthesis of MCM-41 from fly ash was done hydrothermally at 100°C for 72 hours using supernatant of fly ash solution, sodium silicate, tetramethylammonium hydroxide (TMAOH) and cetyltrimethyl-ammonium hydroxide (CTMAOH) surfactants. The effect of Si/Al mole ratio of precursor solution on the structural properties of MCM-41 was studied by variation of the volume composition of supernatant and sodium silicate. The surfactant was removed by calcination at 550°C for 5 hours with heating rate 2°C/minute. The as-synthesized products were characterized by X-ray diffraction, infrared spectroscopy, and nitrogen adsorption methods. The XRD pattern proved that the samples were MCM-41 and the higher the Si/Al mole ratio of precursor solution resulted MCM-41 with higher crystallinity. Calcination was able to remove the CTMAOH surfactant. It was identified by the disappearance of the peak at 3000-2850 cm-1, which is characteristic for CTMAOH. The XRD pattern of calcined MCM-41 showed the decrease of dspacing  and the increase of crystallinity. MCM-41 synthesized with Si/Al mole ratio of precursor solution=44.5 showed the highest crystallinity and has specific surface area=694.5 m2/g, average pore diameter=35Å and pore wall thickness=13.6Å.   Keywords: fly ash, Si/Al mole ratio, MCM-41, crystallinity

scholarly journals Synthesis, Characterization and Textural Analysis of Functionalized Mesoporous Silica Using Sodium Silicate as Precursor and Silicone Surfactant as Template

2014 ◽  
Vol 11 (2) ◽  
pp. 419-428
Author(s):  
Baghdad Science Journal
Keyword(s):  
Mesoporous Silica ◽  
Sodium Silicate ◽  
Nitrogen Adsorption ◽  
Average Diameter ◽  
Functionalized Silica ◽  
Average Pore ◽  
Force Microscopy ◽  
Functionalized Mesoporous Silica ◽  
One Step ◽  
Adsorption Desorption

Three mesoporous silica with different functional group were prepared by one-step synthesis based on the simultaneous hydrolysis and condensation of sodium silicate with organo - silane in the presence of template surfactant polydimethylsiloxane - polyethyleneoxide (PDMS - PEO). The prepared materials were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), atomic force microscopy (AFM) and nitrogen adsorption/desorption experiments. The results indicate that the preparation of methyl and phenyl functionalized silica were successful and the mass of methyl and phenyl groups bonded to the silica structure are 15, 38 mmol per gram silica. The average diameter of the silica particles are 103.51, 167.25 , and 86.41 nm while the average pore diameter are 6.7, 16.4, and 2.7 nm for unfunctionalized, methyl, and phenyl functionalized silica respectively.

Synthesis and Characterization of the Y/MCM-41 Composite Molecular Sieves

2011 ◽  
Vol 480-481 ◽  
pp. 159-164 ◽  
Author(s):  
Li Qin Wang ◽  
Xiang Ni Yang ◽  
Yang Han ◽  
Ning Yu ◽  
Xiu Li Zhao
Keyword(s):  
Pore Size ◽  
Molecular Sieves ◽  
Average Pore Size ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Decomposition Temperature ◽  
Average Pore ◽  
Y Zeolites ◽  
Ft Ir ◽  
Mcm 41

The Y/MCM-41 composite molecular sieves were synthesized in the method of hydrothermal crystallization with cetyltrimethylammonium bromide (CTMABr) as the template agent. The as-prepared composite molecular sieves were characterized by the means of X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), the thermogravimetric and differential thermal analysis (TG-DTA) and the nitrogen adsorption test. The experimental results were shown as follows: the Y/MCM-41 composite molecular sieves kept properties of Y-zeolites and MCM-41 molecular sieves. In the XRD and FT-IR spectra, it can be found both characteristic peaks of Y-zeolites and MCM-41 molecular sieves. The pore size distribution plot indicated that the Y/MCM-41composite molecular sieves had micro-mesoporous structure, and the average pore size were about 1.5 nm and 15 nm. The decomposition temperature of the template agent was at 320 °C, and the calcined temperature of Y-zeolites was at about 560 °C. There showed an endothermic process constantly in the DTA curve, and there was little mass loss in the TG curve, indicating the obtained Y/MCM-41 composite molecular sieves had higher thermal stability.

Utilization of Modified Coal Fly Ash (CFA) as a Catalyst for Production of Biodiesel from Coconut Oil: Part 1 - Characteristics of the Catalyst

2020 ◽  
Vol 981 ◽  
pp. 190-195
Author(s):  
Arif Hidayat ◽  
Achmad Chafidz ◽  
Bachrun Sutrisno
Keyword(s):  
Fly Ash ◽  
Surface Area ◽  
Coal Fly Ash ◽  
Coconut Oil ◽  
Biodiesel Production ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Xrd Pattern ◽  
X Ray ◽  
Ft Ir

The current research studied about the utilization of modified coal fly ash (CFA) as catalyst for biodiesel production from coconut oil. Coal Fly ash (CFA) is a solid waste that is abundantly available in the coal-based power plant. Coal Fly Ash is a type of material that has high content of oxide minerals, e.g. silicates and silicate alumina. With proper physical/chemical treatment, the coal fly ash can be converted into a heterogeneous catalyst. In this work, the coal fly ash was modified with HCl and Ca(NO3)2·4H2O and used as catalyst for biodiesel production from coconut oil. This paper will focus only on the characteristics of the prepared modified CFA-based catalyst. The modified CFA-based catalyst was characterized for its crystallinity using X-Ray Diffraction (XRD), determined its surface area and pore size distribution using Surface Area Analyzer, and its functional groups by Fourier Transform – Infra Red (FT-IR). The specific surface area of the catalyst (modified CFA) decreased from 28.08 m2/g to 17.54 m2/g after impregnation process of calcium oxide in the raw coal fly ash. This decrease was also accompanied by a decrease in the average pore network from 32.59 Å to 20.31 Å. Additionally, based on the XRD pattern shown, the raw CFA is composed of mostly quartz (SiO2) and mullite (3Al2O3.2SiO2) minerals, and a small portion of hematite.

A neutron scattering investigation of the structural properties of glassforming m-toluidine confined in MCM-41

2000 ◽  
Vol 10 (PR7) ◽  
pp. Pr7-95-Pr7-98 ◽  
Author(s):  
D. Morineau ◽  
F. Casas ◽  
C. Alba-Simionesco ◽  
A. Grosman ◽  
M.-C. Bellissent-Funel ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Structural Properties ◽  
Mcm 41

The Effect of Dry Mix Sodium Hydroxide onto Workability and Compressive Strength of Geopolymer Paste

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
A. Z. Mohd Ali ◽  
◽  
N. A. Jalaluddin ◽  
N. Zulkiflee ◽  
◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Alkaline Solution ◽  
High Emission ◽  
New Material ◽  
Curing Regime ◽  
Solid Form ◽  
Geopolymer Paste

The production of ordinary Portland cement (OPC) consumes considerable amount of natural resources, energy and at the same time contribute in high emission of CO2 to the atmosphere. A new material replacing cement as binder called geopolymer is alkali-activated concrete which are made from fly ash, sodium silicate and sodium hydroxide (NaOH). The alkaline solution mixed with fly ash producing alternative binder to OPC binder in concrete named geopolymer paste. In the process, NaOH was fully dissolved in water and cooled to room temperature. This study aims to eliminate this process by using NaOH in solid form together with fly ash before sodium silicate liquid and water poured into the mixture. The amount of NaOH solids were based on 10M concentration. The workability test is in accordance to ASTM C230. Fifty cubic mm of the geopolymer paste were prepared which consists of fly ash to alkaline solution ratio of 1: 0.5 and the curing regime of 80℃ for 24 hours with 100% humidity were implemented. From laboratory test, the workability of dry method geopolymer paste were decreased. The compressive strength of the dry mix of NaOH showed 55% and the workability has dropped to 58.4%, it showed strength reduction compared to the wet mix method.

Adsorption of safranine T from aqueous medium by nano mesoporous MCM-41: adsorption equilibrium, kinetics, and thermodynamics

2020 ◽  
Vol 10 ◽  
Author(s):  
Xiao-Dong Li ◽  
Qing-Zhou Zhai
Keyword(s):  
Electron Microscopy ◽  
Ph Value ◽  
Particle Diameter ◽  
Spherical Particles ◽  
Practical Significance ◽  
Average Particle ◽  
Average Pore ◽  
Kinetics And Thermodynamics ◽  
Safranine T ◽  
Mcm 41

Introduction: In industrial production, a small amount of saffron T emissions will cause increase of water color and increase of chemical oxygen consumption, so study of the decolorization of saffron T wastewater has an important practical significance. Methods: MCM (Mobil Composition of Matter)-41 molecular sieve was synthesized by hydrothermal method. Power Xray diffraction and scanning electron microscopy were used to characterize the sample. Safranine T dye was adsorbed from water by the MCM-41 prepared. Kinetics and thermodynamics of the adsorption were studied. Results: The MCM-41 sample presented spherical particles and regular. The BET (Brunner-Emmett-Teller) specific surface area of the sample determined by 77 K low temperature nitrogen adsorption-desorption isotherm was 932 m2 /g. Its average particle diameter was 110 nm. TEM (transmission electron microscopy) results showed that the sample structure presented a honeycomb pore structure and the average pore diameter was 3.0 nm. The results showed that when room temperature was 20 ± 1 ℃, adsorbate safranine T: adsorbent MCM-41 = 20 : 1，the optimum pH value of adsorption was 4.0 and contact time was 20 min, the adsorption rate reached 98.29% and the adsorption capacity was 19.66 mg/g. The entropy change and enthalpy change of the adsorption system are respectively ΔS0 = 157.5 J/(mol·K); ΔH0 = 21.544 kJ/mol. When temperature was 277.15, 293.15, 303.15 K，the free energy change was respectively △G1 0 = -22.107 kJ/mol, △G2 0 = -24.627 kJ/mol, △G3 0 = -26.202 kJ/mol. Conclusion: The adsorption of safranine T by MCM-41 belongs to a pseudo-second-order adsorption. This adsorption accords with the Freundlich equation and belongs to a heterogeneous adsorption. The adsorption is an endothermic reaction of entropy increase, being spontaneous.

scholarly journals Coal Fly Ash Derived Silica Nanomaterial for MMMs—Application in CO2/CH4 Separation

Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 78
Author(s):  
Marius Gheorghe Miricioiu ◽  
Violeta-Carolina Niculescu ◽  
Constantin Filote ◽  
Maria Simona Raboaca ◽  
Gheorghe Nechifor
Keyword(s):  
Fly Ash ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Coal Fly Ash ◽  
High Surface ◽  
Industrial Applications ◽  
Mixed Matrix Membranes ◽  
Co2 Removal ◽  
Mcm 41

In order to obtained high selective membrane for industrial applications (such as natural gas purification), mixed matrix membranes (MMMs) were developed based on polysulfone as matrix and MCM-41-type silica material (obtained from coal fly ash) as filler. As a consequence, various quantities of filler were used to determine the membranes efficiency on CO2/CH4 separation. The coal fly ash derived silica nanomaterial and the membranes were characterized in terms of thermal stability, homogeneity, and pore size distribution. There were observed similar properties of the obtained nanomaterial with a typical MCM-41 (obtained from commercial silicates), such as high surface area and pore size distribution. The permeability tests highlighted that the synthesized membranes can be applicable for CO2 removal from CH4, due to unnoticeable differences between real and ideal selectivity. Additionally, the membranes showed high resistance to CO2 plasticization, due to permeability decrease even at high feed pressure, up to 16 bar.

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