The effect of synthesis solution pH on the physicochemical properties of Co substituted MCM-41

Pure silica mesoporous molecular sieve (MMS) solid has been synthesized at 100°C by hydrothermal process. The effect of synthesis duration from 2 to 10 days has been investigated on the physicochemical properties of mesoporous molecular sieve. Samples were characterized by low angle XRD, N2adsorption-desorption and HRTEM analysis. XRD patterns of the as-synthesized samples showed four well-defined diffraction peaks corresponding to 100, 110, 200 and 210 planes. These peaks are the fingerprint characteristics of MCM-41 mesoporous material. The high intensity diffraction peaks were observed in 8-days sample that define the high ordering of the pores and long range order. N2adsorption-desorption results showed that all samples possessed a type IV isotherm having hysteresis loop of typeH1which is an identification of mesoporous material. Calcined samples exhibited high surface area i.e., 984-1036 m2g-1, pore volume i.e., 1.00-1.13 cm3g-1and average pore diameter i.e., 3.04-3.30 nm. A hexagonal pore structure was found in the synthesized materials by HRTEM analysis, which confirms that the synthesized materials are MCM-41. HRTEM analysis showed the effect of synthesis duration on the materials and found that 8-days sample exhibited highly ordered hexagonal pore structure like honeycomb structure. All the samples were calcined at 550°C to remove the template and to study the changes in the mesoporous framework. The results showed that the mesoporous structure remained intact after calcination at 550°C, indicating that the mesoporous materials exhibit high thermal stability.

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Synthesis and physicochemical properties of Zr-MCM-41 mesoporous molecular sieves and Pt/H3PW12O40/Zr-MCM-41 catalysts

Journal of Solid State Chemistry ◽

10.1016/j.jssc.2007.08.023 ◽

2007 ◽

Vol 180 (10) ◽

pp. 2958-2972 ◽

Cited By ~ 43

Author(s):

L.F. Chen ◽

J.A. Wang ◽

L.E. Noreña ◽

J. Aguilar ◽

J. Navarrete ◽

...

Keyword(s):

Physicochemical Properties ◽

Molecular Sieves ◽

Mesoporous Molecular Sieves ◽

Mcm 41

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Physicochemical Properties of Diethanolamine-Functionalized Si-MCM-41

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.625.11 ◽

2014 ◽

Vol 625 ◽

pp. 11-14

Author(s):

Sohail Ahmed ◽

Anita Ramli ◽

Suzana Yusup

Keyword(s):

Physicochemical Properties ◽

Structural Integrity ◽

Ftir Spectra ◽

Impregnation Method ◽

Hrtem Micrographs ◽

Diffraction Peaks ◽

Pore Arrangement ◽

Mcm 41

Si-MCM-41 was functionalized with 10-50wt% loading of Diethanolamine (DEA) using impregnation method and characterized for their physicochemical properties using XRD, FTIR and HRTEM. Results show that the intensity of the diffraction peaks attributed to the finger-prints of Si-MCM-41 decreases with increased loading of DEA. The peaks assign to (110), (200), and (210) planes start to disappear at DEA loading as low as 10wt%. FTIR spectra of DEA-Si-MCM-41 show presence of –N-H and –C-H peaks which confirms the functionalization of Si-MCM-41 with DEA. HRTEM micrographs of all samples clearly show the uniform hexagonal pore arrangement which proved the structural integrity of Si-MCM-41 even after functionalization with 50wt%.

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COMPARATIVE STUDY OF THE PHYSICOCHEMICAL PROPERTIES AND PHOTOCATALYTIC ACTIVITY OF MODIFIED MCM-41 SYNTHESIZED BY DIRECT (ONE-STEP) INCORPORATION AND IMPREGNATION

Química Nova ◽

10.5935/0100-4042.20160057 ◽

2016 ◽

Author(s):

Verónica R. Elías ◽

Ema V. Sabre ◽

Sandra G. Casuscelli ◽

Griselda A. Eimer

Keyword(s):

Photocatalytic Activity ◽

Comparative Study ◽

Physicochemical Properties ◽

One Step ◽

Mcm 41

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Influence of Ethanol Concentration and Template Ion Exchange Agent on Template Recycling in Mobil Crystalline Material 41 (MCM-41) Synthesis

ASEAN Journal of Chemical Engineering ◽

10.22146/ajche.50691 ◽

2020 ◽

Vol 19 (2) ◽

pp. 130

Author(s):

Jia Yen Lai ◽

Lock Hei Ngu ◽

Farouq Twaiq

Keyword(s):

Ion Exchange ◽

Ethanol Concentration ◽

Nitrogen Adsorption ◽

Crystalline Material ◽

Hexadecyltrimethylammonium Bromide ◽

Water Mixture ◽

Extract Solution ◽

Exchange Agent ◽

Synthesis Solution ◽

Mcm 41

Recycling of surfactant template for several subsequent MCM-41 synthesis is necessary to reduce substantial synthesis solution disposal. In MCM-41 synthesis, ethanol concentration and template ion exchange agent are two significant factors that affect the silicate polymerization, solvating effect on micelles formation, and MCM-41 mesostructure formation. In view of that, this study investigates recycling of surfactant template ions in extract solution in Mobil Crystalline Material 41 (MCM-41) synthesis. Effect of the ethanol concentrations in the solution gel and the types of ion exchange agents on the yield of MCM-41 material and its surface morphology were studied. Hexadecyltrimethylammonium bromide was used as template for MCM-41 synthesis using tetraethylorthosilicate (TEOS) as silica reagent with ethanol-water mixture as solvent at different ethanol concentrations. Template ions of synthesis gel was exchanged with an ion exchange agent (i.e., 1-butyl-3-methylimidazolium chloride or ammonium nitrate) before it is extracted using synthesis solution. After extraction, the extracting solution was added with TEOS, used for second synthesis cycle and the process continued in an extraction. The template ions in the extract solution were further recycled up to eight synthesis cycles. Yield of calcined materials significantly influenced by ethanol solvent concentrations and however did not vary with various ion exchange agents. Nitrogen adsorption isotherms showed that the calcined materials exhibit MCM-41 characteristics with surface areas ranging from 600 – 1000 m2/g. It is possible to recycle and reuse the surfactant template for several subsequent times of preparing MCM-41 if the ethanol concentration in the solution gel controlled continuously.

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Systematic Investigation of the Synergistic and Antagonistic Effects on the Removal of Pyrene and Copper onto Mesoporous Silica from Aqueous Solutions

Materials ◽

10.3390/ma12030546 ◽

2019 ◽

Vol 12 (3) ◽

pp. 546 ◽

Cited By ~ 1

Author(s):

Haiyan Li ◽

Mengyun Zhai ◽

Hongrui Chen ◽

Chaohong Tan ◽

Xiaoran Zhang ◽

...

Keyword(s):

Heavy Metals ◽

Ionic Strength ◽

Mesoporous Silica ◽

Pore Size ◽

Average Pore Size ◽

Adsorption Behavior ◽

Ph Effects ◽

Solution Ph ◽

Antagonistic Effects ◽

Mcm 41

Polycyclic aromatic hydrocarbons (PAHs) and heavy metals have attracted greater attention due to their single or complex risks. It is urgent to find useful methods to remove these two pollutants together. In this study, SBA15 and MCM-41 were selected and used for the simultaneous removal of pyrene and copper from aqueous solution. Batch experiments were conducted systematically by investigating the adsorption behavior and effects including kinetics, isotherms, ionic strength and pH effects. Experimental results showed that the Langmuir and pseudo-second-order model fitted the adsorption behavior better. The solution pH values and ionic strength affected the adsorption behavior greatly. Furthermore, the synergistic or antagonistic effects could be observed on the adsorption of pyrene and copper onto MCM-41 and SBA15, respectively. The synergistic and antagonistic effects of pyrene and copper onto mesoporous silica may be attributed to the size of pyrene–copper complex and the average pore size of adsorbents. With the higher pore size, the complex would be adsorbed onto the inner surface of MCM-41 which showed synergistic effect on the adsorption of pyrene and copper. This study shows new guidelines and insight into the study of adsorption behavior of PAHs and heavy metals from aquatic environments.

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