介孔硅基分子筛吸附去除挥发性有机化合物的研究进展

Review on Study of Mesoporous Silicon-based Molecular Sieve in the Field of VOCs Adsorption

挥发性有机化合物(VOCs)的排放对生态环境和人体健康产生严重危害。作为VOCs处理的常用方法之一,吸附法因具有成本低、效率高且可回收和再利用等特点而受到广泛关注。介孔硅基分子筛具有高度有序的孔道结构、较大的比表面积和孔容以及孔道表面易于修饰等特点,十分适合作为VOCs的吸附材料,近年来引起研究者们的广泛关注。介孔分子筛中作为VOCs吸附剂的主要为M41S、SBA和HMS等硅基材料,研究表明,介孔硅基分子筛的吸附性能不仅与材料的孔道结构有关,还受分子筛的宏观形貌特征等因素的影响。对介孔分子筛进行引入微孔的结构改进,合成微-介复合结构材料,既能够提升吸附过程的扩散作用,又解决了分子筛孔结构单一的问题,能够达到提升材料吸附性能的同时增强其水热稳定性的目的。此外,就同一种分子筛的宏观形貌而言,其孔道结构越长,越有利于VOCs分子的扩散与吸附。然而,实际工业活动中的VOCs气体中往往会携带水分,由于纯介孔硅分子筛具有亲水性的特点,制约了其广泛应用。因此,近年来除探究介孔硅基分子筛的结构和形貌对VOCs吸附能力的影响外,研究者们主要对分子筛表面环境进行深入研究,通过接枝法和共缩合法等改性方式提升分子筛在潮湿条件下的吸附性能,并取得了长足的进展。本文归纳了近年来介孔硅基分子筛吸附脱除VOCs的研究成果与进展,分别对分子筛结构、形貌和表面环境等影响吸附性能的因素进行介绍,总结了吸附VOCs能力较强的介孔分子筛的特性,指出了吸附VOCs过程的局限性,重点讨论了疏水改性对分子筛吸附能力的提升,并对未来的研究工作进行了展望。

Volatile organic compounds(VOCs)emissions generate severe hazards to the natural environment and human health.As one of the common methods for VOCs treatment,adsorption has drawn extensive concern with its preponderance of low cost,high efficiency,recyclability and reusability.Meanwhile,mesoporous molecular sieves are considered as good candidates for adsorption material due to their distinguished characteristics of highly ordered pore structure,large specific surface area and pore volume as well as ease of functionalization,which has triggered the recent interest of researchers.Some studies show that as common VOCs adsorbents,M41S,SBA,HMS and other silicon-based materials have excellent adsorption properties.The adsorption performance of mesoporous silicon-based molecular sieves is not only related to the pore structure of materials,but also affected by the macroscopic morphology characteristics of molecular sieves and other factors.For example,the structure improvement of mesoporous molecular sieve by introducing micropores to synthesize micro-mesoporous composite structural materials can not only improve the diffusion effect of adsorption process,but also solve the problem of single structure of molecular sieve pores,which can improve the adsorption performance of materials and enhance their hydrothermal stability.In addition,in terms of the macroscopic morphology of the same molecular sieve,the longer the pore structure is,the more conducive it is to the diffusion and adsorption of VOCs molecules.On the other hand,water vapor is often contained in VOCs gases in practical industrial activities.Due to its hydrophilic properties,mesoporous silicon molecular sieves have limited in industrial applications.Therefore,in recent years,in addition to researching on the relationship between mesoporous silica molecular sieve absorption ability of VOCs and the structure and morphology of them,the researchers conduct the thorough research on the main environment on the surface of molecular sieves.By the method of grafting and co-condensation and other modified way of molecular sieve,researchers managed to enhance their adsorption performance in wet conditions.In this paper,recent accomplishments and advances of the adsorption studies on meso-porous molecular sieve used for VOCs removal have been summarized in detail.In the meantime,the influence factors of molecular sieve structure,morphology and surface environment on adsorption performance are introduced,the characteristics of mesoporous molecular sieve with excellent adsorption VOCs capability are summarized,the limitations of adsorption VOCs process are pointed out.Moreover,improvement of adsorption capacity by hydrophobic modification was discussed and the future research work is prospected.