Highly efficient capture of odorous sulfur-based VOCs by ionic liquids.

This study proposes the capture of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) from waste gas using an ionic liquid (IL), namely, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TfN]), and examines the process from a molecular level to the laboratory scale, which is then scaled up to the industrial level. The binding energy and weak interactions between DMS/DMDS and the anion/cation in [EMIM][TfN] were investigated using quantum chemistry calculations to identify the capture mechanism at the molecular scale. A thermodynamic model (UNIFAC-Lei) was established by the vapor-liquid equilibrium data of the [EMIM][TfN] + DMS/DMDS systems measured at the laboratory scale. The equilibrium and continuous absorption experiments were performed, and the results demonstrated that [EMIM][TfN] exhibits a highly efficient capture performance at atmospheric conditions, particularly, absorption capacities (AC) for DMS and DMDS are 189.72 and 212.94 mg g, respectively, and partial coefficients (PC) as more reasonable evaluation metrics for those are 0.509 × 10 and 6.977 × 10 mol kg Pa, respectively, at the 100 % breakthrough. Finally, a mathematical model of the strict equilibrium stage was established for process simulations, and the absorption process was conceptually designed at the industrial scale, which could provide a decision-making basis for chemical engineers and designers.