Use of peroxymonosulfate in wet scrubbing process for efficient odor control

•PMS was firstly utilized as an oxidant for odor removal in wet scrubbing process.•The removal of CH3SH(G) (∼80 ppm/v) maintained high levels of >95%.•PMS reacted with not only CH3S− but also CH3SH(aq).•The stability of PMS was well maintained by adding Na2SiO3 even at high pH.•Three mol of PMS would be necessary to oxidize one mol of CH3SH.

Peroxymonosulfate (PMS) was utilized as an oxidant for methyl mercaptan odor (CH3SH(G), ∼80 ppm/v) removal in wet scrubbing process, and the proposed reaction mechanism was investigated in detail. Under alkaline condition (pH ∼ 12) with PMS, the removal of CH3SH(G) maintained high levels of >95%. The reaction was so quick that no methyl mercaptan ion (CH3S−) in aqueous solution was detected before the depletion of PMS. PMS not only reacted with CH3S−, which was dissociated from the dissolved CH3SH(aq) in alkaline solution, but also directly oxidized the dissolved CH3SH(aq). It was found that 3 mol of PMS would be necessary to oxidize 1 mol of CH3SH. The major product of the oxidation of CH3SH was methanesulfonic acid (CH3SO3−). Additionally, the stability of PMS, by adding sodium silicate (Na2SiO3), was very well maintained even under strong alkaline conditions (less than 5% decomposition). In conclusion, PMS was extremely suitable for CH3SH(G) removal in wet scrubbing process with the existence of Na2SiO3, especially under alkaline condition (pH ∼ 12).