title: Sulfur Dioxide Capture by Heterogeneous Oxidation on Hydroxylated Manganese Dioxide.
abstract: Here we demonstrate that sulfur dioxide (SO2) is efficiently captured via heterogeneous oxidation into sulfate on the surface of hydroxylated manganese dioxide (MnO2). Lab-scale activity tests in a fluidized bed reactor showed that the removal efficiency for a simulated flue gas containing 5000 mg·Nm(-3) SO2 could reach nearly 100% with a GHSV (gas hourly space velocity) of 10000 h(-1). The mechanism was investigated using a combination of experimental characterizations and theoretical calculations. It was found that formation of surface bound sulfate proceeds via association of SO2 with terminal hydroxyls. Both H2O and O2 are essential for the generation of reactive terminal hydroxyls, and the indirect role of O2 in heterogeneous SO2 oxidation at low temperature was also revealed. We propose that the high reactivity of terminal hydroxyls is attributed to the proper surface configuration of MnO2 to adsorb water with degenerate energies for associative and dissociative states, and maintain rapid proton dynamics. Viability analyses suggest that the desulfurization method that is based on such a direct oxidation reaction at the gas/solid interface represents a promising approach for SO2 capture.
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University , Shanghai 200240, China.|Identity Environmental Technology (Shanghai) Co., Ltd., Shanghai 200241, China.
authors.forename: Haodong
authors.initials: H
authors.lastname: Wu
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University , Shanghai 200240, China.|Identity Environmental Technology (Shanghai) Co., Ltd., Shanghai 200241, China.
authors.forename: Weimin
authors.initials: W
authors.lastname: Cai
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University , Shanghai 200240, China.
authors.forename: Mingce
authors.initials: M
authors.lastname: Long
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University , Shanghai 200240, China.|Identity Environmental Technology (Shanghai) Co., Ltd., Shanghai 200241, China.
authors.forename: Hairui
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University , Shanghai 200240, China.
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Wang
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University , Shanghai 200240, China.|Identity Environmental Technology (Shanghai) Co., Ltd., Shanghai 200241, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University , Shanghai 200240, China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Hu
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University , Shanghai 200240, China.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Yu
mesh_terms: D010084:Oxidation-Reduction; D013458:Sulfur Dioxide; D014867:Water
chemical_list: D014867:Water; D013458:Sulfur Dioxide