title: Efficient absorption of SO2with low-partial pressures by environmentally benign functional deep eutectic solvents.
abstract: Sulfur dioxide (SO2) emitted from the burning of fossil fuels is one of the main air contaminants. In this work, we found that environmentally benign solvents, deep eutectic solvents (DESs) could be designed with a function to absorb low-partial pressure SO2from simulated flue gas. Two kinds of biodegradable functional DESs based on betaine (Bet) and l-carnitine (L-car) as hydrogen bond accepters (HBA) and ethylene glycol (EG) as a hydrogen bond donor (HBD) were prepared with mole ratios of HBA to HBD from 1:3 to 1:5, and they were investigated to absorb SO2with different partial pressures at various temperatures. The results showed that the two DESs could absorb low-partial pressure SO2efficiently. SO2absorption capacities of the DESs with HBA/HBD mole ratio of 1:3 were 0.332mol SO2/mol HBA for Bet+EG DES and 0.820mol SO2/mol HBA for L-car+EG DES at 40°C with a SO2partial pressure of 0.02atm. In addition, the regeneration experiments demonstrated that the absorption capacities of DESs did not change after five absorption and desorption cycles. Furthermore, the absorption mechanism of SO2by DESs was studied by FT-IR,1H NMR and13C NMR spectra. It was found that there are strong acid-base interactions between SO2and -COO-on HBA.
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
authors.forename: Shuhang
authors.initials: S
authors.lastname: Ren
authors.affiliation: Department of Chemistry, Taiyuan Normal University, Taiyuan, 030031, China.
authors.forename: Yucui
authors.initials: Y
authors.lastname: Hou
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, 100029, China. Electronic address: wzwu@mail.buct.edu.cn.
authors.forename: Weize
authors.initials: W
authors.lastname: Wu
keywords: Absorption; Deep eutectic solvent; Functionalization; Mechanism; SO(2)