Investigation of the Reaction between Single Na₂CO₃ Droplet and SO₂ Gas in an Electrodynamic Balance

Abstract

Desulfurization reactions of a levitated single Na₂CO₃ droplet under high humidity were followed by electrodynamic balances (EDB) coupled with a Raman spectroscopy. The changes in weight and chemical composition of the single droplet were measured by DC levitation voltage applied to EDB and Raman spectra, respectively. The reaction product between SO₂ and aqueous solution droplet of Na₂CO₃ depended on exposure time of SO₂ gas in EDB chamber. The Raman spectra show that the product was nearly all Na₂SO₃ for short exposure time, but for long exposure time, the addition of SO₂ to Na₂SO₃ led to NaHSO₃ (or NaS₂O₅) as final product. And the produced NaHSO₃ (or NaS₂O₅) particle turned back to Na₂SO₃ through the emission of SO₂ gas under high humidity in the absence of SO₂. Gravimetric analysis based on the DC levitation voltage also indicated that a series of above reactions occurs under desulfurization reaction using the desulfurizing reagents containing Na. It has been demonstrated that EDB was a powerful tool for the kinetic studies of fine droplet such as desulfurization.