Photolysis of low concentration H2S under UV/VUV irradiation emitted from microwave discharge electrodeless lamps

The photolysis of simulating low concentration of hydrogen sulfide malodorous gas was studied under UV irradiation emitted by self-made microwave discharge electrodeless lamps (i.e. microwave UV electrodeless mercury lamp (185/253.7 nm) and iodine lamp (178.3/180.1/183/184.4/187.6/206.2 nm)). Experiments results showed that the removal efficiency (ηH2SηH2S) of hydrogen sulfide was decreased with increasing initial H2S concentration and increased slightly with gas residence time; H2S removal efficiency was decreased dramatically with enlarged pipe diameter. Under the experimental conditions with pipe diameter of 36 mm, gas flow rate of 0.42 standard l s−1, ηH2SηH2S was 52% with initial H2S concentration of 19.5 mg m−3 by microwave mercury lamp, the absolute removal amount (ARA) was 4.30 μg s−1, and energy yield (EY) was 77.3 mg kW h−1; ηH2SηH2S was 56% with initial H2S concentration of 18.9 mg m−3 by microwave iodine lamp, the ARA was 4.48 μg s−1, and the EY was 80.5 mg kW h−1. The main photolysis product was confirmed to be SO42- with IC.