Using vanadyl sulfate to prepare carbon-supported vanadium catalyst for flue gas desulfurization

Abstract

Vanadyl sulfate (VIVOSO4) was used to prepare carbon-supported vanadium catalyst for flue gas desulfurization. The VIVOSO4 impregnated on activated carbon (AC) was easily oxidized into vanadium(V) sulfate phase (possibly V2O3(SO4)2) in air, which exhibited high catalytic activity toward SO2 oxidation, thus significantly enhancing SO2 retention on AC. Furthermore, the vanadium(V) sulfate can be decomposed upon calcination in nitrogen with optimum temperature of 500?C to form vanadium(V) oxide, further improving SO2 retention mainly due to increase in micropore volume suitable for sulfate storage and showing suitability of vanadyl sulfate to prepare traditional V2O5/AC catalyst. To obtain fully oxidized vanadium oxides, preoxidation was carried out on catalyst after calcination. However, due to ablation of carbon support, reduction of vanadium and/or formation of surface oxygen groups, the preoxidation was negative for SO2 retention. Additionally, this paper provided preliminary evidence indicating transformation of vanadium(V) oxide in V2O5/AC into vanadium(V) sulfate during desulfurization. Combined with catalytic role of vanadium(V) sulfate for SO2 oxidation, SO2 removal on V2O5/AC likely followed a mechanism that the vanadium(V) oxide firstly transformed into vanadium(V) sulfate and the latter was then responsible for subsequent SO2 oxidation into H2SO4.