Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Effect of Metal Salt Coagulant on Membrane Fouling During Coagulation-UF Membrane Process

응집-UF 막 공정의 적용시 금속염 응집제가 막오염에 미치는 영향

  • Jung, Chul-Woo (Ulsan Regional Innovation Agency, Ulsan Industry Promotion Techno Park) ;
  • Shim, Hyun-Sool (Division of Construction Engineering, Pukyong National University) ;
  • Sohn, In-Shik (Division of Construction Engineering, Pukyong National University)
  • 정철우 (울산산업진흥테크노파크 전략산업기획단) ;
  • 심현술 (부경대학교 건설환경공학부) ;
  • 손인식 (부경대학교 건설환경공학부)
  • Received : 2007.05.17
  • Accepted : 2007.07.03
  • Published : 2007.10.31
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Abstract

The objectives of this research are to investigate the mechanism of coagulation affecting UF, find out the effect of metal salt coagulant on membrane fouling. Either rapid mixing + UF or slow mixing + UF process caused much less flux decline. For PACl coagulant, the rate of flux decline was reduced for both hydrophilic and hydrophobic membrane than alum due to higher formation of flocs. In addition, the rate of flux decline for the hydrophobic membrane was significantly greater than for the hydrophilic membrane, regardless of pretreatment conditions. In general, Coagulation pretreatment significantly reduced the fouling of the hydrophilic membrane, but did little decrease the flux reduction of the hydrophobic membrane. When an Al(III) salt is added to water, monomers, polymers, or solid precipitates may form. Different Al(III) coagulants (alum and PACl) show to have different Al species distribution over a rapid mixing condition. During the rapid mixing period, for alum, formation of dissolved Al(III) (monomer and polymer) increases, but for PACl, precipitates of $Al(OH)_{3(s)}$ increases rapidly. This experimental results pointed out that precipitates of $Al(OH)_{3(s)}$ rather than dissolved Al(III) formation is major factor affecting flux decline for the membrane.

본 연구에서는 막분리 공정의 전처리 공정으로 응집 공정을 적용할 경우 응집 공정의 적용 가능성을 평가하고자 하였으며 사용된 응집제 종류에 따라 발생하는 금속염이 막오염에 미치는 영향을 파악하고자 하였다. 응집제 종류에 따른 투과 flux 실험결과 응집 공정을 전처리 공정으로 적용할 경우 막의 재질에 상관없이 응집효율이 우수한 PACl의 경우 투과 flux가 높게 나타났으며 전처리 응집 공정의 적용시 급속교반+UF 공정에 비하여 급속-완속교반+UF 공정의 경우 투과 flux 감소율이 낮게 나타났다. 급속교반 공정에 응집제를 첨가할 경우 다양한 형태의 가수분해종이 형성되어졌으며 금속염 응집제가 막오염에 미치는 영향을 살펴보기 위하여 시간에 따른 투과 flux 실험결과 금속염 응집제에 의한 막오염이 발생하였으며 응집제 주입량이 증가할수록 침전물 형태의 금속염 가수분해종의 발생이 증가하여 투과 flux 감소가 크게 나타났다.

Keywords

References

  1. Fan, L., Harris, J. L., Roddick, F. A. and Brooker, N. C., 'Influence of the Characteristics of Natural Organic Matter on the Fouling of Microfiltration Membranes,' Wat. Res. 35(18), 4455-4463(2001) https://doi.org/10.1016/S0043-1354(01)00183-X
  2. Laine, J. M., Clark, M. M. and Mallevialle, J., 'Ultrafiltration of Lake Water: Effect of Pretreament on the Partitioning of Organics,' THMPF, and flux, J, AWWA, 90, 82-87(1990)
  3. Turcaud, L. V., Wiesner, M. R. and Bottero, J. Y., 'Fouling in Tangential flow Ultrafiltration: The effect of Colloid Size and Coagulation Pretreatment,' J. Membrane Sci., 52(2), 173-190(1990) https://doi.org/10.1016/S0376-7388(00)80484-6
  4. Fu, L. F. and Dempsey, B. A., Effects of Charge and Coagulant Dose on Nom Removal and Membrane Fouling Mechanisms,' Proc. AWWA Membrane Technology Conference, New Orleans, 1043-1058(1997)
  5. Song, Y. K., Jung, C. W., Hwangbo, B. H. and Shon, I. S., 'Characteristic of Al(III) Hydrolysis Specie Distribution on Coagulation Process,' Korean Chem. Eng. Res., 44(5), 547-554(2001)
  6. Nystrm, M., Kaipia, L. and Luque, S., 'Fouling and Retention of Nanofiltration Membranes,' J. Membrane Sci., 98(3), 249-262(1995a) https://doi.org/10.1016/0376-7388(94)00196-6
  7. Wang, S. L., Wang, M. K. and Tzou., Y. M., 'Effect of Temperature on Formation and Transformation of Hydrolytic Aluminum in Aqueous Solution,' Colloids and Surfaces, A. 231(1), 143-157(2003) https://doi.org/10.1016/j.colsurfa.2003.08.018
  8. Parker, D. R. and Bertsch, P. M., 'Formation of the Al Tridecameric Polycation Under Diverse Synthesis Condition,' Environ. Sci. & Tech., 26(5), 914-921(1992) https://doi.org/10.1021/es00029a007
  9. Akitt, J. W., Greenwood, N. N., Khandelwal, B. L. and Lester, G. D., '$^{27}Al$ Nuclear Magnetic Resonance Studies of the Hydrolysis and Polymerisation of the Hexa-aquo Aluminum(III) Cation,' J. Chem. Soc. Dalton Trans., 604-610(1972)
  10. Smith, R, M. and Robert, F., in: Gould (Ed.), Relation Among Equilibrium and Nonequilibrium Aqueous Species of Aluminum Hydroxy Complexes in Nonequilibrium Systems: Natural Water Chemistry, ACS Advances in Chemistry Series, 106, American Chemical Society, Washington, DC, 250-279, (1971)
  11. Rebhun, M. and Lulie, M., 'Control of Organic Matter by Coagulation and floc Separation,' Wat. Sci. Tech, 27(11), 1-20(1993) https://doi.org/10.1021/es00038a700
  12. Kang, L. S., Han, S. W. and Jung, C. W., 'Synthesis and Characterization of Polymeric Inorganic Coagulants for Water Treatment,' Korean J. Chem. Eng., 18(6), 965-970(2001) https://doi.org/10.1007/BF02705627
  13. Dempsey, B. A., Reaction Between Fulvic Acids and Aluminum, In Aquatic Humic Substances; Influence on the Fate and Treatment of Pollutant, ACS. (1989)
  14. Lo, B. and Waite, T. D., Structure of Ferric Oxyhydroxide Aggregates-a Light Scattering Study, Chemeca '98 Conference, Port Douglas, September, CD Rom(1998)
  15. Letterman, R. D., Filtration Strategies to Meet the Surface Water Treatment Rule, Denver, CO; American Water Works Association, (1991)