Adsorption materials for volatile organic compounds (VOCs) and the key factors for VOCs adsorption process: A review

Abstract

Volatile organic compounds are harmful to the environment and human health. Adsorption technology has been used to VOCs abatement for over 30 years and has proven to be an effective technology. This work provides a critical review of the recent research developments of VOCs adsorption materials and the key factors controlling the VOCs adsorption process. The average specific surface area, pore volume and VOCs adsorption capacity of different adsorption materials are metal organic frameworks (MOFs) > activated carbons (ACs) > hypercrosslinked polymeric resin (HPR) > zeolites. The mechanism of VOCs adsorption in adsorbent mainly includes electrostatic attraction, interaction between polar VOCs and hydrophilic sites, interaction between non-polar VOCs and hydrophobic sites, and partition in non-carbonized portion. With the specific surface area, pore volume, and surface chemical functional groups increase and the pore size decreases, the adsorption capacity increases. The volume of narrow micropores (size < 0.7 nm) controls the adsorption of VOCs. In addition, methods of activation and surface modification for improving the adsorption capacity of VOCs are discussed. The development of targeted modified adsorption materials and new adsorption materials and reduction of production costs of adsorption materials are especially important in future research.