Use sulfur(IV) stabilizing agent in parallel plate wet denuder for sampling sulfur dioxide in the ambient air

  • 何 翊筠

Student thesis: Doctoral Thesis

Abstract

Formaldehyde is used as an antioxidant to stabilize the sulfite solution in this study In this stabilization process sulfite reacts with formaldehyde solution to form hydroxymethanesulfonate (HMS) which is a relatively stable adduct A parallel plate wet denuder (PPWD) was designed and developed in this study in order to improve the present standard sampling method for acidic gases When SO2 gas flow rates were 2 L/min 5 L/min and 10 L/min the gas absorption efficiencies were 97 4% 96 8% and 95 7% respectively The loss of the absorption efficiency is due to the channeling effect through the partially dried surfaces In the presence of high concentration O3 as oxidant of the sulfur (IV) HMS still has high resistance to O3 When sulfuric acid vapor is added for the experiment the average collection efficiency of SO2 gas is 96 1% which means that in the presence of sulfuric acid vapor it will not affect the collection efficiency of SO2 gas and the average collection efficiency of sulfuric acid gas is 70 1% The low collection efficiency for sulfuric acid vapor may be caused by the low pH value of the absorption liquid The results of outdoor sampling showed that the average collection efficiency was 95 4% which remained above 95% This result is consistent with the results of the laboratory research indicating that this sampling method is suitable for outdoor use
Date of Award2020
Original languageEnglish
SupervisorYee-Lin Wu (Supervisor)

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