Experimental and Simulation Studies on the Capture of Chlorinated Volatile Organic Compounds by Ionic Liquids

The hydrophilic ionic liquid (IL) [EMIM][BF4] was adopted to absorb two chlorinated volatile organic compounds (CVOCs), named 1,2-dichloroethane and 1,1,2-trichloroethane. First, [EMIM][BF4] was screened out as the optimal absorbent from 69 IL candidates by the COSMO-RS model. Then, CVOC absorption experiments were conducted using [EMIM][BF4] and [EMIM][TF2N]. [EMIM][BF4] shows the highest absorption rate for both 1,2-dichloroethane (95.81%) and 1,1,2-trichloroethane (84.91%). Quantum chemical calculations show that both strong intermolecular electrostatic interaction and van der Waals interaction promote the absorption of CVOCs by [EMIM][BF4]. Subsequently, industrial-scale CVOC capture processes, simulation and optimization, were carried out with [EMIM][BF4] and TEG as absorbents, to attain the goal of reducing the concentration of CVOCs in the gas stream to 500 ppm (in mole fraction). The result shows that [EMIM][BF4] has a higher processing capacity and a lower heat duty under optimal operating conditions.