부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.bej.2005.11.005 Byline: Maria Estela A. Giro (a), Oswaldo Garcia (b), Marcelo Zaiat (a) Keywords: Biological oxidation; Bioreactors; Acidithiobacillus ferrooxidans; Ferrous sulfate; Immobilization; Hydrogen sulfide Abstract: The biooxidation of ferrous ion into ferric ion by Acidithiobacillus ferrooxidans can be potentially used for the removal of H.sub.2S from industrial gases. In this work, Fe.sup.3+ ions were obtained through the oxidation of Fe.sup.2+ using the LR strain of At. ferrooxidans immobilized in PVC stands in a pilot-scale bioreactor, while H.sub.2S was removed in an absorption tower equipped with Rasching rings. At. ferrooxidans LR strain cells were immobilized by inoculating the bacterium in a Fe.sup.2+-mineral medium and percolating it through the support. After complete Fe.sup.2+ oxidation, which took around 90h, the reactor was washed several times with sulfuric acid (pH 1.7) before a new cycle was started. Four additional cycles using fresh Fe.sup.2+ mineral medium were then run. During these colonization cycles, the time required for complete iron oxidation decreased, dropping to about 60h in the last cycle. The batch experiments in the H.sub.2S gas removal trials resulted in a gas removal rate of about 98-99% under the operational conditions employed. In the continuous experiments with the bioreactor coupled to the gas absorption column, a gas removal efficiency of almost 100% was reached after 500min. Precipitate containing mainly sulfur formed during the experimental trial was identified by EDX. Author Affiliation: (a) Department of Hydraulics and Sanitation, Sao Carlos School of Engineering, USP Av. Trabalhador Sao-Carlense, 400, 13566-590 Sao Carlos, SP, Brazil (b) Department of Biochemistry and Chemical Technology, Institute of Chemistry, UNESP Araraquara Campus, R. Prof. Francisco Degni s/n, 14800-810 Araraquara, CP 355, SP, Brazil Article History: Received 19 October 2004; Revised 1 September 2005; Accepted 11 November 2005