活性炭对VOCs的吸附研究进展

A Review on VOCs Adsorption by Activated Carbon

挥发性有机化合物(VOCs)是大气主要污染物之一,包括烃类化合物和芳香族化合物,如乙二醇和苯等。VOCs不仅导致温室效应,破坏臭氧层,而且当其浓度偏高时,会引起人体不适,严重时危及生命,因此如何有效地处理VOCs成为学术界和工业界的研究热点。目前,处理VOCs的技术众多,包括催化氧化等破坏性回收技术和吸附等可恢复性技术。相比于在回收过程中不可避免会产生有毒副产物的破坏性回收技术,吸附技术具有VOCs回收效率高、操作简单、能量消耗低等优点,因而被广泛应用。吸附技术的核心是吸附剂。活性炭因具有较高的比表面积、良好的孔道结构以及易于表面官能团改性等优点,被认为是一种具有潜力的VOCs吸附材料。但目前未经改性的活性炭通常比表面积小、表面官能团含量少、对VOCs的吸附能力和选择性较差且疏水能力差,极大地影响了其在潮湿环境中的应用。鉴于此,本文在介绍活性炭对VOCs吸附和脱附原理的基础上,从活性炭的物理结构和表面化学性质两个角度出发,重点介绍不同改性方法(物理改性、化学改性等)改性后的活性炭对VOCs吸附能力和选择性的影响,并对吸附饱和后活性炭的再生方法进行总结。本文旨在系统总结活性炭对VOCs的吸附、解吸和再生机理,以及活性炭改性技术的最新进展,为制备比表面积大、表面官能团丰富的工业化活性炭提供参考。

Volatile organic compounds(VOCs)such as hydrocarbon compounds and aromatic compounds have been recognized as one of the major environmental pollutants.Owing to their toxic and carcinogenic nature,most VOCs harm the environment with ozone sphere damage and threaten human health and lead to irreversible damage after high-concentration exposure.Therefore,industries and research communities face great challenges to effectively remove VOCs by developing practical environment remediation tools and technologies.Several technologies have been investigated,including destructive recovery technologies and recoverable technologies.Compared to other destructive recovery technologies,adsorption is established as one of the most promising strategies for VOCs abatement thanks to its characteristics of cost-effectiveness,simplicity,and low energy consumption.The core of the adsorption technology is the adsorbent.Activated carbon(AC)is considered an excellent adsorbent due to its developed pore structure,high surface area,and a high degree of surface reactivity.However,the structural and surface chemical properties of AC can be quite complicated,which have important effects on the adsorption capacity,selectivity and application in the humid environments.Therefore,the adsorption and desorption mechanism of AC for VOCs is introduced in this work,concerning the effect of diffe-rent modification methods(physical modification,chemical modification,etc.)on the adsorption capacity and selectivity AC,the regeneration methods of AC after adsorption saturation are summarized carefully.This overview provides a comprehensive understanding of VOCs adsorption,desorption,and regeneration mechanisms and up-to-date progress of modification technologies for AC.