The catalytic pyrolysis of biomass is a sustainable approach for biofuel production, contributing to replacing fossil resources with renewable resources . The ZSM-5 zeolite remains an attractive catalyst in the catalytic pyrolysis of biomass, and how to reduce the product diffusion resistance and regulate the surface acidity of ZSM-5 should be explored more deeply. Herein, a hierarchical gallium-modified ZSM-5@SBA-15 catalyst is fabricated through coating a mesoporous layered SBA-15 shell on a hollow ZSM-5 core with gallium modified on the surface, which is effective for increasing hydrocarbon production during the catalytic pyrolysis of biomass process. The synergistic effect of hollowness, mesoporosity, and activity in the hierarchical gallium-modified ZSM-5@SBA-15 catalysts is found to affect the yield and quality of bio-oil. Accordingly, the hierarchical gallium-modified ZSM-5@SBA-15 catalyst with 11 wt% Ga loading exhibits a superior deoxygenation ability, and the relative content of hydrocarbons in bio-oil reach to 49.76 area% which is much higher than that of ZSM-5 (35.30 area%). Furthermore, a possible catalytic pyrolysis mechanism of biomass was also proposed to clarify the potential application of hierarchical gallium-modified ZSM-5@SBA-15 catalysts.
Hydrophobic zeolites have been considered as one of the most promising adsorbents for capturing volatile organic compounds (VOCs). In this contribution, hierarchically structured ZSM-5/SBA-15 composites with different morphologies including platelet, hexagonal prism, long-hexagonal prism, and long-rod were prepared. All materials were characterized using XRD, SEM, and TEM-EDX, which confirmed that the high dispersion of two zeolites within the composites. Due to the presence of intracrystalline mesopores that could shorten the diffusion pathway of toluene, the composites resulted in increased effective diffusion and higher adsorption capacity. The composites also possess higher hydrophobicity, leading to much better toluene adsorption performance under humid conditions. The water contact angle of ZSM-5 could be increased from 15.6° to 44.9° by forming well dispersed zeolite composites. The 29 Si MAS NMR results confirmed that the composites possess higher amount of Q 4 groups (75.3%–80.1%), which is the intrinsic reason for higher hydrophobicity. Notably, ZSM-5/SBA-15-hexagonal prism resulted in the best adsorption performance and cycling stability when compared with pure ZSM-5, the breakthrough time was increased from 20.8 to 49.4 min under dry conditions and from 5.9 to 27.3 min in the presence of 50% relative humidity. This work represents an important scheme for making hydrophobic zeolite-based VOCs adsorbents with also improved toluene diffusion properties due to the unique hierarchical porous structure.
危险品化学品经营许可证（带存储）