Screening Identification And Application In Flue Gas Desulfurization Of Acidithiobacillus Ferrooxidans

An Acidithiobacillus ferrooxidans (A.f) with high ferrous ion oxidation rate was isolated. The culture medium and the conditions were studied. The flue gas desulfurization conditions were studied. The mechanism of the microbiology desulfurization technology was discussed.Strain N16 was isolated from the soil collected from chemical plant, which can oxidize 62.3% ferrous ion. Based on its morphologic and cultural characteristics and the sequence of 16S rDNA, the strain was determined as A.f.The main components of the medium were optimized one by one. The optimum medium were consist of:(NH4)2SO41 g/L, MgSO4·7H2O 0.5 g/L, K2HPO40.5g/L, KCl0.1g/L, Ca(NO3)20.01 g/L, FeSO4·7H2O 60 g/LBy the software SAS, the culture condition optimization was designed with Box-Behnken way. And the results were analyzed with the response surface analysis(RSA). The optimum culture condition was:pH 1.8, temperature 28℃, inoculum volume 15%, a 250 mL flask containing 30 mL medium. Under the optimum condition, the oxidation rate of ferrous ion reached at 99.8%.A laboratory desulfurization experiment was carried out in the 5L fermentor. The factors which effected on the desulfurization rate were studied. The optimum condition was:SO2 concentration in entry gas 2500mg/m3, gas velocity 180L/h, temperature 28℃, Fe3+ concentration 0.8g/L, pH 2.0. By this condition, the desulfurization rate reached at 98.7%.The mechanism of the microbiology desulfurization technology was discussed. In this system, the synergy act with A.f and Fe3+. They absorbed and oxidized SO2.