MCM-41

About: MCM-41 is a research topic. Over the lifetime, 2355 publications have been published within this topic receiving 91416 citations.

One-pot synthesis of Aluminum-containing ordered mesoporous silica MCM-41 using coal fly ash for phosphate adsorption

Abstract: The present study offers an economic one-pot synthesis of Al-containing ordered mesoporous silica MCM-41 from the coal fly ash. The samples were characterized by small-angle XRD, N2 adsorption, TEM, mapping, 27Al MAS NMR, EDX, and NH3-TPD. The effects of pH values to the final mesostructures have also been investigated. The results show that the material prepared at the pH value of 10 displays the largest pore volume of 0.98 cm3/g, the highest BET surface area of 1020 m2/g, and the lowest Si/Al molar ratio of 2. Using this material as adsorbent for phosphates, the adsorption capacity reaches 64.2 mg/g at 298 K, which is much higher than that of large pore mesoporous silica SBA-15 (53.5 mg/g), diatomite (62.7 mg/g), and MCM-41 (31.1 mg/g). In addition, the thermodynamics and kinetics for the phosphate adsorption were also investigated. Our present study shows an economic way to treat phosphates using the industrial solid waste of coal fly ash.

The influence of supported Ni catalysts on the product gas distribution and H2 yield during cellulose pyrolysis

Abstract: Two groups of Ni catalysts, supported on γ-Al 2 O 3 and MCM-41, respectively, were prepared by incipient wetness impregnation and tested for their influence on the pyrolytic decomposition of cellulose. A thermogravimetric analyser coupled with a mass spectrometer (TG–MS) was used to examine the influence of catalyst loading, support material, and the presence of additional water vapour on H 2 selectivity. Normalization of the raw MS data enabled semi-quantitative analysis of the product gas distribution, which facilitated reliable comparison between different experimental conditions. Catalysts were characterized by BET, XRD, SEM/EDX and TEM. MCM-41 supported Ni significantly elevated the yield of H 2 and total gaseous product, both under Ar and with the injection of additional water vapour when compared with the γ-Al 2 O 3 support. 15 wt.%Ni/γ-Al 2 O 3 and 5 wt.%Ni/MCM-41 were identified as the most active catalysts from the two groups with regards to H 2 selectivity and yield.

Alkylguanidine-catalyzed heterogeneous transesterification of soybean oil

Abstract: Transesterification of soybean oil with methanol has been carried out in the presence of heterogenized alkylguanidines as catalysts. The alkylguanidines were anchored to modified polystyrene or siliceous MCM-41, encapsulated in the supercages of zeolite Y, or entrapped in SiO 2 sol-gel matrices. The catalytic activity of these catalysts was compared with that of their homogeneous counterparts, showing that the yields of methyl esters obtained in the homogeneous phase can be obtained with the guanidines anchored to the supports after longer reaction times. The catalysts prepared by immobilization of alkylguanidines in microporous systems showed diffusion restrictions for the vegetable oil as well as the low stability of the inorganic framework.