毛白杨木材/MOF-5复合材料的制备及甲苯吸附性能研究

Study on Preparation and Toluene Adsorption Performance of Populus tomentosa Wood/MOF-5 Composite Material

优化MOF-5的合成工艺,确定金属中心与有机配体的最佳配比,并基于最佳配比通过真空浸渍和水热作用在毛白杨木材孔隙内部原位合成MOF-5,制备毛白杨木材/MOF-5复合材料,并对毛白杨木材/MOF-5复合材料的微观形貌、结合机理、孔隙结构和甲苯吸附性能进行表征。结果表明,当金属中心与有机配体物质的量比为1∶3时,合成的MOF-5晶体粒径较小,BET比表面积为268.729 m^(2)/g,孔容为0.136 cm^(3)/g,且具备典型的MOF-5晶体X射线特征峰。在毛白杨木材孔隙内部原位合成的MOF-5的平均负载量为22.6%;红外光谱的分析结果显示MOF-5与毛白杨木材通过氢键和静电相互作用相结合。扫描电镜、压汞法和氮气吸/脱附测试的孔隙结构表明,MOF-5填充了毛白杨木材中的部分大孔和介孔,增加了微孔的比表面积和孔容。常温常压下毛白杨木材/MOF-5复合材料对甲苯的最大吸附量为16.07 cm^(3)/g,展现了较好的甲苯吸/脱附性能。毛白杨木材/MOF-5复合材料在气体吸附与分离领域展现了较好的应用潜力,这为速生木材作为吸附材料的功能化应用提供了参考。

The optimal ratio of the metal centers to the organic ligands was determined by optimizing the synthesis process of MOF-5.Based on the optimal ratio,Populus tomentosa wood/MOF-5 composite material was prepared by in situ synthesis of MOF-5 in the pore of Populus tomentosa by vacuum impregnation and hydrothermal synthesis.The morphology,binding mechanism,pore structure,and toluene adsorption property of the adsorbent material were characterized.The results showed that when the molar ratio of metal center to organic ligand was 1∶3,the synthesized MOF-5 crystals had a small particle size.The BET specific surface area was 268.729 m^(2)/g,the pore volume was 0.136 cm^(3)/g.MOF-5 crystals presented peak characteristics in the typical X-ray exam.The average loading value of MOF-5 synthesized in situ inside the pore of Populus tomentosa was 22.6%.The infrared spectroscopy test showed that MOF-5 was combined with Populus tomentosa through hydrogen bonding and electrostatic interactions.The pore structure tested by scanning electron microscopy,mercury intrusion porosimetry,and nitrogen adsorption and desorption showed that MOF-5 filled some of the macropores and mesopores in the Populus tomentosa,while increasing the specific surface area and pore volume of micropore.The maximum adsorption capacity of toluene was 16.07 cm^(3)/g at normal temperature and pressure,and Populus tomentosa wood/MOF-5 composite material showed good toluene adsorption and desorption performance.Populus tomentosa wood/MOF-5 composite material demonstrated a good potential in gas adsorption and separation,which is a reference for promoting fast-growing wood as adsorbent material.