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A comparative evaluation of ten catalysts for biomass pyrolysis was performed using poplar (DN-34) as the feedstock. Five of the catalysts consisted of HZSM-5 with different silica:alumina ratios (SAR, 23, 30, 55, 80 and 280). The other five catalysts were sulfated zirconia (SO4 2− ZrO 2 ), 20% SO4 2− ZrO 2 dispersed on a mesoporous MCM-41 silica support, Al–MSU–S alumnosilicate exhibiting a foam-like mesopore structure, Al–MSU–S aluminosilicate exhibiting wormhole mesopores, and a bauxite waste product known as red mud. Analytical pyrolysis in tandem with GC/MS showed that all of the catalysts except for HZSM-5 resulted in low aromatic chemical production. Highly acidic sulfated zirconia catalysts were not selective to aromatics and produced significant coke and non-condensable gases. Mesoporous MSU–S catalysts exhibiting high pore volume and acidity also gave high gas and coke yields. Among the HZSM-5 catalysts evaluated, those with the lowest SAR provided the highest yields of total aromatics and the lowest levels of undesired coke. [ABSTRACT FROM AUTHOR]

Abstract: Polymeric mesocomposite membranes were prepared via wet phase inversion processes by incorporating surfactant-templated mesoporous silica particles, denoted MSP-1, into polysulfone matrices formed with and without PEG as a molecular porogen. Transmission electron microscopy and N2 adsorption–desorption measurements showed higher surface area (354m2/g), smaller average pore size (53nm), and larger pore volume (2.92cm3/g) with a narrower pore size distribution (26nm width at half-maximum) for surfactant-templated mesoporous silica particles compared to those of precipitated commercially available mesoporous silica, HiSil. The distinct morphological changes induced by PEG and by MSP-1 were redundant from the membrane performance point of view as they translated into similar performance gains that were not additive, pointing to the potential use of mesoporous additive as an alternative porogen. The higher hydrophilicity and unique structural features of MSP-1 resulted in enhanced performance of the prepared membranes compared to MSP-free controls and HiSil-based mesocomposites. Mechanical properties of mesocomposites and neat polysulfone membranes were comparable. Electron microscopy coupled with flux and rejection measurements were used to investigate the influence of polymer content, MSP loading, and the presence of porogen on the structure and separation properties of mesocomposite membranes. Mesocomposite membranes showed increased water flux and dextran rejection. For ultrafiltration membranes the figure of merit, operationally-defined as the product of water flux and rejection of 12kDa dextran, increased by the factor of 2.8 (for membranes cast with a porogen) and 6.3 (in the absence of porogen) upon incorporation of the mesoporous additive at the loading of 10wt%. Enhancement factors were 3.7 and 11.2 for less permeable membranes cast from mixtures with higher (20wt%) polymer content. Fouling tests with humic acid solutions demonstrated that mesocomposite membranes experienced lower flux decline and showed higher rejections. [Copyright &y& Elsevier]

Zeolites with uniform intracrystal mesopores, designated MSU-MFI, were prepared using silane-modified polymers as mesopore-generating agents. X-ray diffraction analysis of this catalyst showed Braggs peaks representative of MFI structure. Catalyst characterization by nitrogen physisorption revealed a mesoporous structure with high surface area, pore size and volume. The MSU-MFI catalysts developed in this study were selective toward aromatic chemical production from poplar pyrolysis vapour. Yields of generalized products and aromatics were comparable to those obtained from conventional microporous ZSM-5 analogs as demonstrated by pyroprobe-gas chromatography/mass spectrometry and thermogravimetric analysis. While ZSM-5 was more selective to smaller C6 aromatics and naphthalenes, MSU-MFI catalysts were more selective to C8 and C9 monoaromatics. The incorporation of gallium(III) ions in MSU-MFI using the incipient wetness method increased aromatic yields by up to 15% over Ga-free catalysts and decreased the coke production by up to 6% (p < 0.05). Due to high yields and low coke formation, Ga-MSU-MFI offers an improved option for making non-oxygenated aromatic chemicals from photosynthetic biomass. [ABSTRACT FROM AUTHOR]