Study On Removal Sulfur Dioxide Of Thiobacillus Ferrooxidans

The SO₂removal going through with microbiological method was experimentallystudied in the article, carrying out with analysis and study on bacteria culture,identification and growth characteristics study of Thiobacillus ferrooxidans （T.f.）, andon effect of heavy metal ions to the growth activity of bacteria and operating conditionsof SO₂removal with bio-trickling filter of activated carbon filler.The bacteria for experiment, screening out from the sludge and soil, wereconfirmed as T.f after several separation and purification and biological identification.The growth cycle of bacteria was about32hours, reaching the logarithmic growth phasearound20hours, oxidation rate of Fe²⁺was relatively high. The Fe²⁺can be oxidized tothe minimum size by T.f around28hours. During the growth of bacteria, the pH valueincreased gradually and then decreased, reaching the maximum value of2.46around16hours, and finally stabilized at1.8to1.9. During the growth of bacteria, the value ofFe³⁺/Fe²⁺enhanced with the increase of Fe3+and the pH value increased gradually withtime, the result was consistent with the Nernst equation. The jarosite precipitationgenerated during the growth of bacteria had no obvious effect on the growth of bacteria,and the hungry T.f can adsorb on the jarosite precipitation growing with some elementsof precipitation to supply needed ions.Simple analysis on the effect of heavy metal ions to the activity of T.f was made inthe experiment, main results indicated that during the shortdated growth, the biomassand Fe²⁺ion oxidation rate could be facilitated by the concentration of Mn²⁺between0.4mg/L².0mg/L, and restrained the concentration of by Cu²⁺、Pb²⁺、Hg²⁺between0.4mg/L².0mg/L、0.2mg/L¹.0mg/、0.01mg/L⁰.05mg/L. The effect of Hg²⁺washighest. Filler biofilm forming of bio-trickling filter shall be done with the combination ofbiofilm forming in and out of the filter. When the temperature was25-30℃，the inletmass concentration of SO₂was less than1740mg/m³, spray volume of0.9L/h，residencetime of gas about80s and concentration of Fe²⁺≥2.6g/L，the removal efficiency can beabout90%.