HWAHAK KONGHAK, Vol.32, No.2, 179-186, April, 1994
미생물 탈황공정에 의한 해성점토의 개량
Improvement of a Marine Clay by a Microbial Desulfurization Process
초록
해성점토로부터 세라믹 재료생산에 적합한 점토를 얻기 위하여, 황 산화 박테리아인 Thiobacillus ferrooxidans를 해성점토중의 pyrite(FeS2) 제거에 사용하였다. 이러한 미생물 탈황에 의해 pyrite가 다량 함유되어 있는 해성 점토로부터 양질의 점토를 얻을 수 있었다. 점토의 탈황속도와 제거율에 대한 여러 공정변수들의 영향을 조사하였다. 속도는 좀 느렸지만 T.ferrooxidans의 접종 없이도 점토내의 자생균에 의해서도 75%정도의 pyrite를 제거 할 수 있었다. T.ferrooxidans의 성장을 위해 필요한 영양분의 상당 부분을 점토에 함유되어 있는 염들로부터 얻을 수 있음을 알 수 있었다. 배양액의 pH와 산화된 pyrite양과의 관계는 pH=A-K log[FeS2]로 표현되었다. 비교적 낮은 값으로부터 70%(w/v)까지 이르는 점토 slurry 농도에서 7-12일 동안에 80-90%의 pyrite 를 제거할 수 있었다. T.ferrooxidans에 의한 pyrite산화속도는 slurry농도에 따라 506-1,714mg -FeS2/L.day의 값을 보였고, pyrite의 농도에 대해 1차식(ΥC=8.424SC)으로 표현될 수 있었다. 해성점토를 개량하기 위한 다단 생물반응기를 사용하는 연속 미생물 탈활공정을 제안하였다.
To make a clay suitable for the production of ceramics, from a marine clay, a sulfur-oxidizing bacterium Thiobacillus ferrooxidans was used for the removal of pyrite(2.4wt
% FeS2) from the marine clay. Influences of several process variables including microorganisms involved, slurry concentration, and medium composition were evaluated in terms of the rate of pyrite removal. Although the reaction rate was slow, a significant amount of pyrite in the clay could be also removed only by the inherent microorganisms in the clay without inoculation of T. ferrooxidans. A good fraction of the nutrients requirement was supplied from the clay itself. When a pyrite-adapted T. ferrooxidans was used, about 80-90% of the pyrite was removed in 7-12 days for slurry densities up to 70 w/v%. The relationship between the amount of oxidized pyrite per volume and pH could be expressed as pH=A-K log[FeS2]. The rate of pyrite oxidation ranged from 506 to 1,714 mg-FeS2/L-day depending upon slurry concentration. A process concept for continuous microbial desulfurization of clay was proposed in the present study.
% FeS2) from the marine clay. Influences of several process variables including microorganisms involved, slurry concentration, and medium composition were evaluated in terms of the rate of pyrite removal. Although the reaction rate was slow, a significant amount of pyrite in the clay could be also removed only by the inherent microorganisms in the clay without inoculation of T. ferrooxidans. A good fraction of the nutrients requirement was supplied from the clay itself. When a pyrite-adapted T. ferrooxidans was used, about 80-90% of the pyrite was removed in 7-12 days for slurry densities up to 70 w/v%. The relationship between the amount of oxidized pyrite per volume and pH could be expressed as pH=A-K log[FeS2]. The rate of pyrite oxidation ranged from 506 to 1,714 mg-FeS2/L-day depending upon slurry concentration. A process concept for continuous microbial desulfurization of clay was proposed in the present study.
- Groudev SN, Groudev VI, Biotechnol. Bioeng., 16, 91 (1985)
- Torma AE, Adv. Biochem. Eng., 6, 1 (1977)
- Beyer M, Ebner HG, Klein J, Appl. Microbiol. Biotechnol., 24, 342 (1986)
- Ryu HW, Yoo HJ, Chang YK, Kim SD, Proc. 3rd Asian Conference on Fluidized Bed and Three-Phase Reactors (Chun, H.S. and Kim, S.D., eds.), 628-642, KyongJu, Korea (1992)
- Ryu HW, Chang YK, Kim SD, Korean Inst. Energy Eng., 1, 135 (1992)
- Ryu HW, "Microbial Desulfurization of Coal and Development of a High Performance Bubble Column Bioreactor," Ph.D. Thesis, Korea Advanced Institute of Science and Technology, Taejon, Korea (1993)
- Ryu HW, Chang YK, Kim SD, Fuel Process. Technol., in press, 36 (1993)
- Ryu HW, Chang YK, Kim SD, HWAHAK KONGHAK, 31(3), 325 (1993)
- Kargi F, Robinson JM, Biotechnol. Bioeng., 24, 2115 (1982)
- Kargi F, Robinson JM, Biotechnol. Bioeng., 27, 41 (1985)
- Larsson L, Olsson G, Holst O, Kalsson HT, Appl. Environ. Microbiol., 56, 697 (1990)
- Andrews GF, Darroch M, Hansson T, Biotechnol. Bioeng., 32, 813 (1988)
- Andrews GF, Maczuga J, Biotechnol. Bioeng., 12, 337 (1982)
- Detz CM, Barvinchak G, Min. Congr. J., 65, 75 (1979)
- Klein J, Beyer M, Afferden MV, Hodek W, Seewald FH, Wolff H, Fischer E, Juntgen H, "Biotechnology," vol. 6, (Rehm, H.J. and Reed, G. eds.) VCH, Weinheim, FRG, pp. 497-567 (1988)
- Uhl W, Hone HJ, Beyer M, Klein J, Biotechnol. Bioeng., 34, 1341 (1989)
- Monticello DJ, Finnerty WR, Annu. Rev. Microbiol., 39, 371 (1985)
- Cho KS, Zhang L, Hirai M, Shoda M, J. Ferment. Technol., 71, 44 (1991)
- Cho KS, Hirai M, Shoda M, J. Ferment. Technol., 71, 384 (1991)
- Imaizumi T, Biotechnol. Bioeng., 16, 363 (1985)
- Silverman MP, Lundgren DG, J. Bacteriol., 77, 642 (1959)
- ASTM, "Standard Method for Forms of Sulfur in Coal," ASTM Annual Book, D2492, 05, American Society for Testing and Materials, Philadelphia, 350 (1985)
- Furman NH, "Standard Methods of Chemical Analysis," Vol. 1, 6th ed., 553-555, Robert E. Krieger Publishing Co., Huntington, New York (1962)
- Chandra D, Mishira AK, "Bioprocessing and Biotreatment of Coal," (ed. by Donald L. Wise), 631-652, Marcel Dekker Inc., New York and Basel (1990)
- Lacey DT, Biotechnol. Bioeng., 24, 29 (1970)
- Hoffman MR, Faust BC, Panda FA, Koo HH, Tsuchiya HM, Appl. Environ. Microbiol., 42, 259 (1981)
- Personal Communication with Prof. Tadahiro Mori, Environmental Biotechnology Laboratory, Shimane University, Japan