Investigation of a Ni-Modified MCM-41 Catalyst for the Reduction of Oxygenates and Carbon Deposits during the Co-Pyrolysis of Cellulose and Polypropylene

Abstract

Catalytic fast co-pyrolysis of biomass and plastic is an effective method to achieve high-quality bio-oil production. In this work, (Ni)-MCM-41 catalysts with different Ni loadings were prepared and characterized in detail by using a variety of advanced analytical techniques, and the effects on the catalytic performance were analyzed by micropyrolysis with gas chromatography mass spectrometry (Py-GC/MS) and thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) methods. The results showed that an appropriate amount of Ni addition can effectively modulate the physicochemical properties of MCM-41. For a Ni loading of 25.1 wt % (Cat-C), the catalyst showed an optimal catalytic performance, a decrease in the proportion of oxygenated compounds in the product from 35.6 (MCM-41) to 13.4%, and an increase in the relative total amount of olefins plus aromatics from 62.2 (MCM-41) to 84.6%. The excellent catalytic performance of Cat-C can be ascribed to a balancing of its proper physical structural properties, appropriate acidity, strong metal–carrier interaction, high metal dispersion, and excellent compatibility balance between active and acidic sites.

Highly ordered pure and indium-incorporated MCM-41 mesoporous adsorbents: synthesis, characterization and evaluation for dye removal

“…That is, at high indium content, a portion of the indium will be exposed and accumulate at the openings of the pores or unevenly dispersed on the MCM-41 surface. This causes partially blocking of the meso-channels and less adsorption of nitrogen gas so that both the pore volume and the specific surface area decrease with increasing the indium content [49]. On the other hand, if the metal content is not so high, as in IM0.05 sample, the probability for metal ions to accumulate on the surface is low, alternately the metal ions can only incorporate deep within the silica framework, so the decline of V p might not happen and might be increased due to the increased indium-oxygen bond [48].…”

Effect of CTAB Ratio to the Characters of Mesoporous Silica Prepared from Rice Husk Ash in the Pyrolysis of a–cellulose

“…Overall, pyrolysis over MS catalyst was shown to produce higher level of oxygenated compounds. This is likely due to the high surface area and porous structure provided by MS that leads to the increase of diffusion limits, which improves the interactions between reactants and active sites, thus, facilitating macromolecular reaction involving large volumes of molecules [21,22]. In addition to furan, ketones and alcohol are also obtained in a higher number in the catalyzed pyrolysis.…”

Enhancing the Synergistic Effect of Cellulose and Polypropylene for Petrochemical Production during Catalytic Fast Pyrolysis by Mesoporous Gallium-MFI Zeolites

“…To enhance petrochemical production and reduce solid residue formation, researchers have tried cofeeding lignocellulosic biomass with hydrogen-rich plastic wastes during CFP. − Different synergistic effects have been reported when varying plastics (e.g., polyethylene (PE) and polypropylene (PP)) and lignocellulosic biomass (e.g., cellulose, hemicellulose, and lignin) are cofed in CFP. , The most significant synergy is observed for cofeeding PE and cellulose in CFP with ZSM-5 zeolites, where the carbon yield of valuable aromatic hydrocarbons can be considerably increased from ∼30–35 C% for CFP of individual cellulose and PE to ∼50% for the cofeed CFP of their mixtures. Meanwhile, the formation of solid residues can be substantially decreased during cofeed CFP of PE and cellulose mixtures. ,, However, insignificant synergistic effects are generally observed during cofeeding PP and cellulose in CFP with ZSM-5 zeolites, although PP has the same elemental composition as PE. ,, …”

“…In contrast, because of the methyl side chains in PP molecules, PP produces mainly branched olefins (e.g., 2,4-dimethyl-1-heptene and 4-methyl-2-undecene) during thermal cracking. , During CFP of PE and cellulose mixtures with ZSM-5 zeolites, PE-derived linear olefins can easily diffuse into the zeolite pores and then react with cellulose-derived furans through the Diels–Alder mechanism to form aromatic hydrocarbons. , Therefore, cofeeding PE and cellulose in CFP can significantly enhance aromatic production, compared to CFP of the two components individually. However, it has been suggested that, because of the steric hindrance effect of side chains, PP-derived branched olefins are more difficult to diffuse into the pores of ZSM-5 and react with cellulose-derived furans, thus resulting in the insignificant synergy for aromatic production during the cofeed CFP of PP and cellulose. ,,, …”

“…However, it has been suggested that, because of the steric hindrance effect of side chains, PP-derived branched olefins are more difficult to diffuse into the pores of ZSM-5 and react with cellulosederived furans, thus resulting in the insignificant synergy for aromatic production during the cofeed CFP of PP and cellulose. 19,28,30,32 To alleviate the steric hindrance effect of branched olefins, zeolites that have larger pore sizes than ZSM-5 zeolite (e.g., beta and Y zeolites) have been tested as the catalyst for cofeed CFP of PP and cellulose. 25,26,32 However, the results indicate that, while these zeolites facilitate the diffusion and reaction of PP-derived branched olefins with cellulose-derived furans, their large pore sizes are not favorable for aromatic production.…”