Adsorption of SO₂ and Its Transformation to SO₄^2- on the Surface of Fly Ashes and Coal Soot

Abstract

Air containing SO₂ gas of about 1, 10 and 100 ppm under various humidities was contacted with fly ashes of oil and coal combustion, and smoke particles emitted from a coal stove.
The amount of SOX adsorbed on the oil combustion fly ash is in agreement with those obtained by Tartalleri et al. and Liberti et al. On the other hand, Haury et al. gave much higher adsorption probably because they tested fly ashes of high heavy metal content. Our analysis also revealed that high SO₂ sticking coefficient given by Judeikis et al. is due to their false assumption in their derivation of SO₂ adsorption on the particles.
It is also found that the rate of production of SO₄^2- on the surface of atmospheric fly ash and soot particles at relative humidities below 80% is too low to be significant in air chemistry.