憎水性ZIFs对糠醛和5-羟甲基糠醛的吸附分离性能

Adsorption Separation Performance of Hydrophobic ZIFs for Furfural and 5-Hydroxymethylfurfural

糠醛(furfural)和5-羟甲基糠醛(HMF)是重要的生物质平台化合物。针对低浓度生物质平台化合物的吸附分离,研究了典型沸石咪唑酯骨架(ZIFs)材料结构与糠醛和5-羟甲基糠醛吸附分离性能的关系。选择两种孔径不同但孔容接近的憎水ZIFs材料(6元环ZIF-8和8元环MAF-6)用于吸附分离糠醛和5-羟甲基糠醛,分别研究了静态吸附、吸附动力学、竞争吸附、动态穿透性能。实验结果表明:对于糠醛吸附量,ZIF-8(0.48g/g)和MAF-6(0.52g/g)接近;对于5-羟甲基糠醛吸附量,ZIF-8(0.39g/g)和MAF-6(0.40g/g)接近。对于吸附动力学,MAF-6对糠醛和5-羟甲基糠醛吸附在20min达到平衡,而ZIF-8在6h以上才能达到平衡。进一步的动态穿透结果显示:与ZIF-8相比,MAF-6对糠醛的动态吸附快速达到平衡;MAF-6对5-羟甲基糠醛动态吸附容量远大于ZIF-8.最后研究了ZIF-8和MAF-6对双组分糠醛/5-羟甲基糠醛的吸附分离性能,结果显示,ZIF-8分离糠醛/5-羟甲基糠醛受动力学控制;而MAF-6分离糖醛/5-羟甲基糖醛是由热力学控制。

Furfural and 5-hydroxymethylfurfural (HMF) are important biomass platform compounds. We Studied the relationship between the structure of typical zeolitic imidazolate framework (ZIFs) and the adsorption separation properties of furfural and 5-hydroxymethylfurfural for the adsorption separation of low concentration biomass platform compounds. Two kinds of hydrophobic ZIFs were selected, ZIF-8 with six-memberedring and MAF-6 with eight-membered, which have different pore diameters and closed pore volume. The performance of static adsorption, adsorption kinetics, competitive adsorption and dynamic breakthrough were studied. The experimental results show that the adsorption amount of furfural on ZIF-8 (0.48 g/g) was close to that on MAF-6 (0.52 g/g);and the adsorption amount of 5-hydroxymethylfurfural on ZIF-8 (0.39 g/g) was also close to that on MAF-6 (0.40 g/g). For adsorption kinetic, the equilibrium time of furfural and 5-hydroxyfurfural on MAF-6 was 20 min, while that on ZIF-8 was more than 6 h. Further dynamic breakthrough results show that the dynamic adsorption of furfural onto MAF-6 quickly reached equilibrium compared with ZIF-8;the dynamic adsorption capacity of 5-hydroxyfurfural on MAF-6 was much higher than that of ZIF-8. Finally, the adsorption separation performance of two-component furfural/5-hydroxymethylfurfural on ZIF-8 and MAF-6 was studied. The results show that the separation of furfural/5-hy-droxymethylfurfural on ZIF-8 was based on kinetics, and that of MAF-6 was based on thermodynamics.