Study On Removal Of Hydrogen Sulfide From Acidic Industrial Gas By Biotechnology

Along with the strength of environmental protection regulation and the day by day requiring strictness of environmental protection ,the development research of biodesulfurization technique has become the issue solved forwardly in environmental protection field. The indirect oxidation of Thiobacillus ferrooxidans was used in this thesis.Through the technology of immobilization,cell dencity and productivity were increased.The closed cycle desulfurizing unit mainly composed of fix-bed bioreactor and gas absorption tower was constructed.We studied the bacteria,reactor and absorption tower.Thiobacillus ferrooxidans conserved in our laboratory was mutagenized by ultraviolet radiation and microwave.Compared with the bacteria without being mutagenized,the oxidation ability of the bacteria breeded increased of 81%;During the shake culture,ferrous iron was oxidized into ferric iron by Thiobacillus ferrooxidans and a series of hydrolysis reaction of ferric iron took place.Finally ferric precipitation is formed.By X-ray diffraction spectra we proved the precipitaton was jarosite.We discussed the forming mechanism and the infulunce of the concentration of Fe2+ and pH on the amount of precipitation;The fixed-bed bioreactor with effective volume 3L and bed voidage 0.333 was constructed. We examined the We preliminarily researched the absorption process of cells during the immobilization.examined the influence of aeration rate,pH and the concentration of Fe3+ in the culture medium on the fixed bed bioreactor.For the first time we discussed the influence of jarosite on the process and effect of immobilization;The gas absorber was designed and built up. We studied the removal of H2S in acidic industrial gas and studied the effects of liquid gas ratio and concentration of absorbent on the abatement efficiency of H2S.The result showed when the liquid gas ratio was more than 0.5,the abatement efficiency of H2S exceeded 99%.When the concentration of Fe3+ in the absorption liquid was less than 6.1g/L,the abatement efficiency of H2S was augmented with the increase of concentration of Fe3+.The continuous increase of concentration of Fe3+ in the absorption had no influence on the abatement efficiency of H2S essentially.The consecutive operation, of the whole technological process was carried through and the abatement efficiency of H2S was more than 99%.The result showed this technological process could be operated continuously for a long time.