Papers by Keyword: MCM-41

Abstract: This study aims to evaluate the adsorption performance of an amine-functionalized MCM–41 mesoporous silica nanoparticles system (MCM–41–NH₂) as an adsorbent for the removal of different pharmaceutical pollutants from aqueous solutions. The modification of MCM-41 was achieved through post-synthesis treatment in the presence du 3-Aminopropyltriethoxysilane (APTES). Surface and structural characteristics of MCM-41 and MCM–41–NH₂ were examined using N₂ adsorption–desorption analysis, X-ray diffraction, Fourier transform infrared spectroscopy, and point of zero charge analysis. In addition, thermal stability was investigated by thermogravimetric analysis. The kinetics study shows that adsorption on MCM–41–NH₂ follows pseudo-second-order rate expression. Isotherm study showed that the experimental data fitted well with the Langmuir equation. Moreover, the maximum adsorption capacities of MCM–41–NH2 were: (129.8, 272.0, 233.2 and 318.6) mg/g for Diclofenac, Ibuprofen, Oxacillin and Trihydrated Amoxicillin respectively). The adsorption is controlled by the surface charges of the adsorbent and the adsorbate. Compared with other adsorbents, MCM–41–NH₂ was more effective for the different pharmaceutical removal.

Abstract: Ultrasound waves with 48 KHz of frequency were applied for the synthesis of MCM-41 using rice husk as the silica source. The effect of sonication time (30, 60, 90, 120, 150, 180, and 210 min) on the crystallinity of calcined MCM-41 was investigated. Characterization using XRD and FTIR indicated that the ordered structure of MCM-41 could be synthesized by ultrasonic wave. Sonication time at 150 min was found to be the optimum condition. The nitrogen adsorption-desorption isotherms informed that the mesoporous material produced at the optimum condition has 794.73 m²·g^-1of surface area, 3.02 nm of BJH pore diameter, 1.17 nm of wall thickness, and 0.68 ml·g^-1 of pore volume. While based on the TEM image, the material has hexagonal or a honey-comb structure.

Abstract: The CO₂ adsorption technology using solid adsorbent shas been considered as a promising approach to reduce CO₂ emissions. Therefore, research has been developed to obtain efficient and economically viable adsorbents. The mesoporous materials of the MCM-41 type are among the candidates for effective adsorbents as a result of easy synthesis and structure which favors the flow of gas. The aim of this study was to improve the synthesis of MCM-41 using mixtures of cationic surfactants and apply in CO₂ capture. The cationic surfactants used weretetradecyltrimetylammonium bromide (TTMABr - C₁₇H₃₈NBr) and cetyltrimethylammonium bromide (C₁₉H₄₂NBr) and their mixture in a ratio of 1:1. The CO₂ adsorption was investigated using the gravimetric method at 298K and pressure varying up to 40 bar. The resulting materials, C₁₇, C₁₉ and C₁₇C₁₉, were characterized by XRD, FTIR, TG and SEM. The results revealed significant differences in the structure of the materials and amount of of CO₂ adsorbed.

Abstract: In order to improve the efficiency of TiO₂, material with large surface area such as mesoporous silica is usually used as a support. In this study, the TiO₂ was dispersed on mesoporous silica, MCM-41 by an impregnation method, meanwhile the bulk TiO₂ was prepared by sol gel method. The X-ray diffraction (XRD) patterns showed that the intensities of diffraction peaks for MCM-41 decreased with the increase of the TiO₂ loading, suggesting that the higher loading amount of TiO₂ might lead to less ordered structure of MCM-41. The successful addition of TiO₂ on MCM-41 was also confirmed from the fluorescence spectra, which the emission intensities of TiO₂ and MCM-41 increased and decreased, respectively, with the increase of TiO₂ loading on the MCM-41. The activities were compared between the bulk and dispersed TiO₂ for photocatalytic oxidation of hexanol. Both bulk and dispersed TiO₂ on MCM-41 showed good photocatalytic activity, while the MCM-41 did not show photocatalytic activity. Since the efficiency of photocatalyst can be defined by its respective turnover number (TON), the comparison between bulk and dispersed TiO₂ on MCM-41 was made based on their TON values. It was revealed that the dispersed TiO₂ on the MCM-41 with 5 wt% of TiO₂ loading was the most efficient photocatalyst among all the samples.

Abstract: SAPO-34 molecular sieve was successfully synthesized using calcined-MCM-41 as silica source and morpholine as a template. The influence of MCM-41 content on the synthesis was investigated. The result shows that pure SAPO-34 could be obtained in a wide range of the n (SiO₂)/n (Al₂O₃) ratio in the starting gel. Moreover, increase the n (SiO₂)/n (Al₂O₃) ratio has a negative effect on crystallinity while high silicon incorporates into the framework of SAPO-34. Keywords: MCM-41, SAPO-34, Silicon source,

Abstract: The main objective was to synthesize in the laboratory and characterize the molecular sieve MCM-41. This study has a strong experimental character. The hydrothermal synthesis was performed at 100 ° C for a period of 7 days. The resulting materials were characterized by XRD, EDX, Adsorption Capacity and the Foster Swelling test. Through XRD verified the formation of mesoporous structure. Different organic solvents, namely gasoline, diesel and kerosene were used. The Foster Swelling Test results indicated that the affinity of molecular sieve MCM-41 occurred in the treated clay tested in all organic solvents (gasoline, diesel, kerosene), without and with agitation.

Abstract: In the present work, the adsorption of heavy metal ions using amine-functionalized MCM-41 was investigated. Amine-functionalized MCM-41 was synthesized by incorporation of tertiary amine functional group namely 3-[2-(2-aminoethylamino) ethylamino] propyltrimethoxysilane (AEPTMS) into MCM-41 through co-condensation method. The resultant adsorbents were characterized using elemental analysis, FTIR, and N₂ adsorption-desorption. Amine-functionalized MCM-41 showed higher Cu²⁺ adsorption capacity of 4.52 mg/L compared to 0.94 mg/L for MCM-41 .

Abstract: The Mg-Al mixed oxides were deposited on the MCM-41 via the coprecipitation followed by thermal decomposition and characterized by many techniques. In the transesterification of glycerol (GL) with dimethyl carbonate (DMC), the resulting supported catalysts exhibited much higher catalytic performance than the pure Mg-Al mixed oxides, which was ascribed to the increased basicity. Under the optimal reaction conditions, the obtained data showed that at DMC/glycerol molar ratio of 3:1, catalyst loading of 0.3 g and reaction temperature of 373 K, the glycerol conversion and glycerol carbonate yield from the process was 98.7 % and 92.5%, respectively.

Abstract: In this paper, meso-porous MCM-41 was synthesized at room temperature using cationic surfactant cetyltrimethylammonium bromide (CTAB) as the template agent. Then MCM-41/unsatura-ted polyester resin (UPR) materials were prepared by in-situ polymerization with the meso-porous MCM-41. MCM-41/UPR in-situ composites were prepared by roller milling and molding processes. Effects of meso-porous MCM-41 on rheological properties and wear resistance of the MCM-41/UPR composites have been investigated. It is shown that MCM-41 has a diameter in range of 4-5 nm and the pores are highly ordered. MCM-41 can improve the rheological properties and wear resistance of the composites. When MCM-41 content is 2%, the mass abrasion loss is decreased by 37.4%.

Abstract: A mesoporous molecular sieve MCM-41 dimensional hexagonal arrangement has a diameter of 2-10 nm, thermal stability, high pore volume and high surface area. In the synthesis of MCM-41 is used as the CTMABr directing agent and tetraethyl orthosilicate (TEOS) as silica source. Several studies have been developed using the residue of bagasse sugar cane, due to the high percentage of silica in its composition, making it a promising source for materials synthesis, favoring the use of this product impactful to the environment. This paper aims at the synthesis and characterization of MCM-41 with molar composition: 1.0 CTMABr: 4.0 SiO₂: 1 Na₂O: 200 H₂O using waste. The materials were characterized by the techniques of X-ray Diffraction (XRD), chemical analysis by X-ray spectrometry, energy dispersive (EDX) spectroscopy and in the infrared (IR). ). By XRD and IR verified the formation of mesoporous molecular sieve MCM-41. The XRD of the as-synthesized samples MCM-41 displayed the characteristic (1 0 0) reflection of typical MCM-41, with EDX was observed high silica content in the residue of bagasse sugar cane.