Study On Mechanism Of SO₂ Oxidation By Pyrolusite Slurry Combined With Thiobacillus Ferrooxidans And Manganese Bacteria

Catalysis oxidation of SO₂ by low concentration pyrolusite slurry is a new methods for desulphurization from waste gas.But with the reaction time increased, the desulphurization efficiency will be depressed notably.A new way by adding bacteria to renew iron and manganese ion's activities, to realize the catalyzer's rebirth, and to keep a higher desulphurization efficiency has been proposed. This paper studies the reaction mechanism of SO2 by pyrolusite slurry, pyrolusite slurry combined with Thiobacillus ferrooxidans and Manganese bacteria to promote it used in industry.For the desulphurization system of pyrolusite, it shows that redox is dominating and the lixiviating rate of manganese is more than 85% at the first period (about 40 minutes before), but after 40 minutes catalysis stands on the leading position and the ratio of [SO₄²-] and [Mn²++Fe²+] is about 169.As the ratio of [Mn²+] and [Fe²+] is about 38, the effect of iron ion can be neglected and the synergetic effect between iron and manganese ion is unconspicuous. And the solid components of pyrolusite are proved that they have catalytic actions.For the desulphurization system of pyrolusite combined with Thiobacillus ferrooxidans, It shows that effect of the microorganism is not only from the iron ions inside the culture base but also from themselves, that Thiobacillus ferrooxidans can transform Fe²+ to Fe³+. It also indicates that the production of SO₄²- is enhanced in pace with the increase of the concentration of pyrolusite slurry,the amount of T.f,the percent of O₂,the flow of gas by investigation oftechnologic conditions. Inlet concentration of SO2 exists a maximum value for the production of SO42".For the desulphurization system of pyrolusite combined with Manganese bacteria, it shows that the microorganism has no effect if concerned with desulphurization efficiency. But through contrasting experiment, it proves that the function of microorganism is unassailable from the lixiviating manganese ion. It is obvious that Manganese bacteria can transform Mn2+ to some solid-state substances.The mechanism of the united effect of Thiobacillus ferrooxidans and Manganese bacteria is complicated and needs further researchJn this experiment the synergetic effect between the two bacillus is ambiguous.