Exploration on the Source of So42- in Condensable Particulate Matter

Condensable particulate matter (CPM) attracts wide attention as an emerging pollutant that pollutes the environment and affects human health. CPM consists of organic and inorganic components, of which the SO42−, as the anion with the largest proportion of the inorganic component of CPM, is still unclear as to its source. In this paper, two schemes based on simulated flue gas (SFG) and real flue gas (RFG) experimental systems separately were adopted to explore the potential sources of SO42− in CPM. The SFG experiment was performed by configuring the SFG containing determined concentrations of various S-containing substances. Also, the interference of SO2 on CPM measurement caused by dissolution and the effect of nitrogen purging were revealed. In the RFG experiment, some S-containing substances were extra added to the combustion system individually, and the source of SO42− was judged through observing the change of SO42− detected in CPM. It was found through experiment that SO42− in CPM was mainly from SO3/H2SO4 in flue gases, and the contribution of varied sulfates was little. The positive error factor caused by the dissolution of SO2 increases with the increasing SO2 concentration and cannot be eliminated by nitrogen purging.