Efficient SO₂ Removal and Highly Synergistic H₂O₂ Production Based on a Novel Dual-Function Photoelectrocatalytic System

Abstract

The direct conversion of SO2 to SO3 is rather difficult for flue gas desulfurization due to its inert dynamic with high reaction activation energy, and the absorption by wet limestone-gypsum also needs the forced oxidation of O2 to oxidize sulfite to sulfate, which is necessary for additional aeration. Here, we propose a method to remove SO2 with highly synergistic H2O2 production based on a novel dual-function photoelectrocatalytic (PEC) system in which the jointed spontaneous reaction of desulfurization and H2O2 production was integrated instead of nonspontaneous reaction of O2 to H2O2. SO2 was absorbed by alkali liquor then oxidized quickly into SO4 2– by a nanorod α-Fe2O3 photoanode, which possessed high alkali corrosion resistance and electron transport properties. H2O2 was produced simultaneously in the cathode chamber on a gas diffusion electrode and was remarkably boosted by the conversion reaction of SO3 2– to SO4 2– in the anode chamber in which the released chemical energy was effectively used to increase H2O2. The photocurrent density increased by 40% up to 1.2 mA·cm–2, and the H2O2 evolution rate achieved 58.8 μmol·L–1·h–1·cm–2 with the synergistic treatment of SO2, which is about five times than that without SO2. This proposed PEC cell system offers a cost-effective and environmental-benign approach for dual purpose of flue gas desulfurization and simultaneous high-valued H2O2 production.

A Review of Photoelectrocatalytic Reactors for Water and Wastewater Treatment

“…Although this review is based on aqueous PEC water treatment, PEC gaseous/air treatment has also been investigated [100]. A brief example is the two-compartment design of Mei et al [101] tested with an AM 1.5 (100 mWcm −2 ) source for the oxidation of sulphur dioxide (SO2) to sulphate (SO 4…”

“…Although this review is based on aqueous PEC water treatment, PEC gaseous/air treatment has also been investigated [100]. A brief example is the two-compartment design of Mei et al [101] tested with an AM 1.5 (100 mWcm −2 ) source for the oxidation of sulphur dioxide (SO 2 ) to sulphate (SO −2 4 ) which requires a strong alkaline electrolyte (NaOH was used as the anolyte in this study, pH = 13.65), with a nanorod-like hematite photoanode, which is reported to have high durability and corrosion resistance in alkali environments [102]. The counter electrode was a gas diffusion electrode to produce H 2 O 2 , the catholyte was 0.1 M Na 2 SO 4 in H 2 SO 4 (pH = 3) and the electrolytes were separated by a bipolar membrane.…”

Preparation of TiO2/porous glass-H with the coupling of photocatalysis oxidation–adsorption system in the initial position and its desulfurization performance on model fuel

“…This phenomenon can be explained by the photocatalytic adsorption desulfurization mechanism, where organosulfur compounds are rstly photocatalytically oxidized to sulfoxides or sulfones through photocatalytic active components, which are then selectively adsorbed on the photocatalytic oxidation-adsorption bifunctional material due to the high polarity of the sulfoxides or sulfones produced. [43][44][45] TiO 2 /porous glass-H showed a much higher photocatalytic oxidation-adsorption desulfurization efficiency than TiO 2 /porous glass in a specic period. This is mainly because of the larger surface area and narrower band gap width of TiO 2 /porous glass-H, resulting in a higher UV absorption capacity.…”

Dynamic Simulation of Integrated Cleaner Production Strategies towards High Quality Development in a Heavily Air-Polluted City in China

“…Optimal technology selection. Currently, the most used desulfurization and denitrification processes are the limestone-gypsum method and selective non-catalytic reduction (SNCR) denitrification technology [51,52], which account for more than 95% of the pollutant removal technologies employed in Tangshan City. However, owing to the problems of single processes and secondary pollution, advanced technologies should be adopted and selected to improve pollutant removal efficiency.…”