DOI QR코드

DOI QR Code

금속이온에 의한 조류 응결에 관한 연구

Studies on the Flocculation of Algae with Metal Ions

  • 박영재 (호서대학교 생명공학전공) ;
  • 이상수 (배재대학교 생명공학과) ;
  • 조혜륜 (한국원자력연구원 원자력화학연구부)
  • Park, Yeong Jae (Department of Biotechnology, Hoseo University) ;
  • Lee, Sang Soo (Department of Life Science and Technology, Pai Chai University) ;
  • Cho, Hye Ryun (Nuclear Chemistry Research Division, Korea Atomic Energy Research Institute)
  • 투고 : 2015.07.07
  • 심사 : 2015.08.24
  • 발행 : 2015.08.31

초록

본 연구에서는 시아노박테리아 배양액을 대상으로 여러 종류의 금속이온의 첨가에 의한 응집 및 응결 효과를 흡광도 또는 제타포텐셜 측정을 통하여 조사하였다. 흡광도 측정으로부터 얻은 시아노박테리아의 응결효율은 $Al^{3+}$>$La^{3+}$>$Ho^{3+}$>$Fe^{2+}$>$Ca^{2+}$ 순으로 높았으며, 특히 동일한 전하량을 갖는 +3가 금속이온의 경우, 응결 시 수반되는 금속 제거율을 측정한 결과, $Al^{3+}$>$La^{3+}$>$Ho^{3+}$ 순으로 응결효율과 상응하는 결과를 얻었다. 시아노박테리아의 제타포텐셜은 음의 값을 나타냈으며, 그 농도가 증가할수록 제타포텐셜 값도 증가하였다. 또한, 시아노박테리아 용액의 pH를 증가시킬 때 pH < 5.5 이하에서는 빠르게 제타포텐셜 값이 감소하였으나, $5.5{\leq}pH{\leq}10$ 범위에서는 거의 일정한 제타포텐셜 값($-46{\pm}1mV$)을 보였다. 일정한 시아노박테리아의 농도($A_{730}=0.25$)에서 금속이온의 농도에 따른 제타포텐셜 증가 효과는 $Al^{3+}$>$Ho^{3+}$>$La^{3+}{\gg}Mg^{2+}{\geq}Ca^{2+}{\gg}K^+$ 순으로 나타났다. 일정한 금속이온 농도에서 시아노박테리아의 농도에 따른 제타포텐셜 변화를 측정한 결과, $K^+$, $Mg^{2+}$$Ca^{2+}$이온의 경우 시아노박테리아의 농도가 증가하더라도 제타포텐셜의 변화가 미미하였다. 반면에, +3가 이온 중 $Ho^{3+}$$La^{3+}$이온의 경우에 시아노박테리아의 농도가 증가할수록 제타포텐셜 값이 감소하였으며, 감소율 면에서 $Ho^{3+}$이온이 $La^{3+}$이온보다는 작게 얻어졌다. 이와는 달리, $Al^{3+}$이온의 경우에는 시아노박테리아의 농도가 증가함에 따라 제타포텐셜 값이 증가하다가 감소하였다. $Al^{3+}$이온은 가수분해 중합체 생성의 영향으로 제타포텐셜 측정만으로는 응집 내지 응결 효과를 해석하기가 어려웠다.

Studies on the flocculation of algae using various metal ions were carried out by measurements of optical density(OD) and zeta potential. Cyanobacteria were used as algaes. Flocculation efficiencies of cyanobacteria by an addition of metal ions were determined from OD values, and the effect of metal ions was greater in the order of $Al^{3+}$>$La^{3+}$>$Ho^{3+}$>$Fe^{2+}$>$Ca^{2+}$. Especially for trivalent metal ions, percentages of metal removed from cyanobacteria solutions on flocculation were measured, showing the same order as in flocculation efficiencies. Zeta potentials of cyanobacteria alone were measured with increasing the concentration, found to be all negative voltages, and were increased with increasing the concentration. The effect of pH on zeta potential of cyanobacteria solution was investigated. Below pH 5.5, the zeta potentials were steeply decreased with increasing pH, whereas in the range of $5.5{\leq}pH{\leq}10$ they were almost constant ($-46{\pm}1mV$) even with increasing pH. At a constant concentration of cyanobacteria ($A_{730}=0.25$), an increase in concentration of metal ions caused an increase in zeta potential of cyanobacteria solution, showing that the effect was greater in the order of $Al^{3+}$>$Ho^{3+}$>$La^{3+}{\gg}Mg^{2+}{\geq}Ca^{2+}{\gg}K^+$. At a constant metal concentration, zeta potentials were measured with increasing cyanobacteria concentration, showing that zeta potentials for $K^+$, $Mg^{2+}$ and $Ca^{2+}$ ions were negligibly changed, whereas those of $Ho^{3+}$ and $La^{3+}$ ions were decreased. Moreover, the effect of $Ho^{3+}$ ion on decreasing zeta potential was smaller than that of $La^{3+}$ ion. $Al^{3+}$ ions showed quite a different behavior that with increasing cyanobacteria concentration the zeta potentials increased and decreased thereafter. Hydrolysis of $Al^{3+}$ ions caused a difficulty to investigate coagulation or flocculation of cyanobacteria by measurement of zeta potential.

키워드

참고문헌

  1. Grima, E. M., Belarbi, E. H., Fernandez, F. G. A., Medina, A. R. and Chisti, Y., "Recovery of microalgal biomass and metabolites: process options and economics," Biotechnol. Adv., 20, 491-515(2003). https://doi.org/10.1016/S0734-9750(02)00050-2
  2. Wyatt, N. B., Gloe, L. M., Brady, P. V., Hewson, J. C., Grillet, A. M., Hankins, M. G., Pohl, P. I., "Critical conditions for ferric chloride-induced flocculation of fresh water algae," Biotechnol. Bioeng., 109(2), 493-501(2012). https://doi.org/10.1002/bit.23319
  3. Wu, Z., Zhu, Y., Huang, W., Zhang, C., Li, T., Zhang, Y. and Li, A., "Evaluation of flocculation induced pH increase for harvesting microalgae and reuse of flocculated medium," Bioresour. Technol., 110, 496-502(2012). https://doi.org/10.1016/j.biortech.2012.01.101
  4. Liu, J., Tao, Y., Wu, J., Zhu, Y., Gao, B., Tang, Y., Li, A., Zhang, C. and Zhang, Y., "Effective flocculation of target microalgae with self-flocculating microalgae induced by pH decrease," Bioresour. Technol., 167, 367-375(2014). https://doi.org/10.1016/j.biortech.2014.06.036
  5. Wan, C., Alam, M. A., Zhao, X. Q., Zhang, X. Y., Guo, S. L., Ho, S. H., Chang, J. S. and Bai, F. W., "Current progress and future prospect of microalgal biomass harvest using various flocculation technologies," Bioresour. Technol., 184, 251-257(2015). https://doi.org/10.1016/j.biortech.2014.11.081
  6. Uduman, N., Qi, Y., Danquah, M. K., Forde, G. M. and Hoadley, A., "Dewatering of microalgal cultures: A major bottleneck to algae-based fuels," Renew. Sustain. Energ., 2: 012701(2010). https://doi.org/10.1063/1.3294480
  7. Ives, K. J., "The significance of surface electric charge on algae in water purification," J. Biochem. Microbiol. Technol. Eng., 1(1), 37-47(1959). https://doi.org/10.1002/jbmte.390010105
  8. Kwon, D. Y., Jung, C. K., Park, K. B., Lee, C. G. and Lee, J. W., "Flocculation Characteristics of Microalgae Using Chemical Flocculants," Korean Soc. Biotechnol. Bioeng. J., 26, 143-150(2011).
  9. Kwon, D. Y., Jung, C. K., Lee, C. G. and Lee, J. W., "Flocculation Characteristics of Microalgae Through Combined Flocculants," Korean Soc. Biotechnol. Bioeng. J., 26, 443-452(2011).
  10. Son, S. M., Jutidamrongphan, W. and Park, K. Y., "Addition of Coagulants for Phosphorus Removal from Combined Sewer Overflows (CSOs)," J. Korean Soc. Water and Waste., 26, 295-302(2012). https://doi.org/10.11001/jksww.2012.26.2.295
  11. Susana, G. F., Maria. C. I. and Humberto, J. S., "Effect of a cyanobacterial community on calcium carbonate precipitation in Puente del Inca," Acta Bot. Croat., 61(1), 1-9(2002).
  12. Rita, K. H., Simon, A. P. and Bruce, J., "The impact of differing cell and algogenic organic matter (AOM) characteristics on the coagulation and flotation of algae," Water Res., 44, 3617-3624(2010). https://doi.org/10.1016/j.watres.2010.04.016
  13. Lee, D. Y., Chung, S. J., Park, S. S. and Jung, B. O., "Flocculation Effect of Chitosan by Z-potential," J. Chitin. Chitosan, 19, 138-142(2014).
  14. Ko, S. H., Paik, S. Y. R. and Ryu, J. N., "Comparison of Physicochemical Properties of Calcium Carbonate Nano-and Micro-Powders," Food Eng. Prog., 16, 134-138(2012).
  15. Rippka R. and Cohen-Baziere G., "The cyanobacteriales: a legitimate order based on the type of strain Cyanobacterium stanieri?," Ann Microbiol. (Paris). 134B(1), 21-36(1983).
  16. Golueke, C. G. and Oswald, W. J., "Harvesting and Processing Sewage-Grown Planktonic Algae," J. Water Pollut. Contr., 37, 471-498(1965).
  17. Arthur, E. M and Robert, M. S., "Critical Stability Constants; Vol. 3 : Other Organic Ligands," 2nd ed., Plenum Press, New York, pp. 3-59(1989).
  18. Robert, M. S. and Arthur, E. M, "Critical Stability Constants ; Vol. 4 : Inorganic Complexes," 2nd ed., Plenum Press, New York and London, pp. 1-12(1981).