Research progress on the recovery of VOCs by absorption using green solvents

Volatile organic compounds (VOCs) are serious air pollutants, with their main sources being automobile exhaust emissions and production processes such as chemical, petroleum refining industries, causing greater harm to human health and the environment. The absorption is an effective method for treating VOCs, and has mature process conditions and low technical cost. Compared with organic solvents, green solvents have great advantages in reducing environmental pollution, protecting human health, and promoting the development of green industry, when used for VOCs recovery. Ionic liquids (ILs), deep eutectic solvents (DESs) and aqueous solvent are the three most important green solvent systems, among which ILs and DESs are more popular in the study of effect and mechanism, while aqueous solutions are widely used. This study primarily reviews the research progress of absorption technologies for benzene series, chlorinated VOCs, volatile alcohols, and polar VOCs using three types of green solvents. It further summarizes the absorption mechanisms of these solvents: ILs and DESs rely on weak molecular interactions and π—π interactions, while aqueous solvents enhance VOCs absorption by incorporating surfactants to achieve interfacial solubilization effects. Finally, the application prospects and future development trends of green solvents are discussed.