Land and Housing Review (토지주택연구)

Land and Housing Research Institute (한국토지주택공사 토지주택연구원)
권호 표지
DOI QR코드

DOI QR Code

Effect of Ionic Molar Conductivity on Separation Characteristics of Heavy Metals by Nanofiltration Membranes in Waste Water

이온 몰 전도도가 나노여과막에 의한 폐수 중의 중금속 분리특성에 미치는 영향

  • 오정익 (한국토지주택공사 토지주택연구원)
  • Received : 2012.09.24
  • Accepted : 2013.01.16
  • Published : 2013.01.30
Download PDF
⟨ Previous Next ⟩

Abstract

Generally, the characteristic of nanofiltration membranes were catagorized into charged membrane, sieve effect, interaction between membarnes and target solutes. This study aims to investigate the effect item of heavy metal separation with view of charge nanofiltration membranes. The experiments of nanofiltration were conducted by nanofiltration set-up with operational pressure of 0.24 MPa at $25^{\circ}C$ by using synthetic wastewater containing 0.1mg/L of Cr, Fe, Cu, Zn, As, Sn, Pb. Nanofiltration membranes rejected heavy metals much better than chloride, sulfate and TOC, of which concentration in synthetic wastewater was higher than that of heavy metals. To consider rejection characteristics of various metals by nanofiltration membranes, separation coefficient, which is the molar conductivity ratio of the metal permeation rate to the chloride ion or TOC permeation rate, was introduced. In spite of different materials and different nominal salt rejection of nanofiltration membrane used, the separation coefficients of metals were nearly the same. These phenomena were observed in the relationship between the molar conductivity and the separation coefficient for heavy metals.

나노여과막은 일반적으로 하전막이며, 용질의 하전성, 막과의 상호작용에 의해서 특징 있는 분리특성을 보인다. 본 연구에서는 나노여과막에 의한 폐수 중의 중금속류의 제거에 미치는 하전특성을 조사했다. 크롬(Cr), 철(Fe), 구리(Cu), 아연(Zn), 비소(As), 주석(Sn), 납(Pb)을 각각 0.1mg/L 첨가한 모의폐수를 제조하여 나노여과막(a)와 나노여과막(b)를 이용하여 운전압력 0.24MPa, 온도 $25^{\circ}C$에서 여과실험을 수행하였다. 그 결과, 나노여과막(a)와 나노여과막(b)에 의한 염소 이온의 제거율은 12.8%, 3.5%였고, 황산이온의 제거율은 78%, 9.3%였고 TOC의 제거율은 70.4%, 26.2%이었다. 한편, 중금속의 제거율은 나노여과막(a)의 경우 크롬(Cr) 92.5%, 철(Fe) 90.9%, 구리(Cu) 93.1%, 아연(Zn) 92.6%, 비소(As) 74.6%, 주석(Sn) 97.3%, 납(Pb) 93.4%이었고, 나노여과막(b)의 경우는 크롬(Cr) 69.9%, 철(Fe) 84.6%, 구리(Cu) 87.0%, 아연(Zn) 73.3%, 비소(As) 15.2%, 주석(Sn) 80.1%, 납(Pb) 87.7%이었다. 여기서, 나노여과(a), 나노여과(b)의 경우 공통적으로 크롬, 철, 동, 아연, 주석, 납에 비하여 비소의 제거율은 상대적 낮았다. 상기 실험결과에서 폐수 중에 다량 함유되는 염소이온 및 황산이온에 대한 중금속류의 분리계수와 이온성분의 수중에서의 활동정도를 나타내는 인자인 이온 몰 전도도로 해석할 수 있었다. 그 결과, 몰 전도도 비가 큰 중금속 이온일수록, 나노여과막에 의한 중금속 이온의 제거율이 높아지는 경향을 알 수 있었다.

Keywords

References

  1. Agenson, K. O., J. I. Oh, T. Urase (2003), "Retention of a wide variety of organic pollutants by different nanofiltration/reverse osmosis membranes: controlling parameters of process", Journal of Membrane Science, 225: 91-103. https://doi.org/10.1016/j.memsci.2003.08.006
  2. Bruggen, B., M. Manttari, M. Nystrom (2008), "Drawbacks of applying nanofiltration and how to avoid them: A review", Separation and Purification Technology, 63(2): 251-263. https://doi.org/10.1016/j.seppur.2008.05.010
  3. Ceankoplis, C. J. (1992), Transport process and unit operation, University of Minnesota, 2nd edition.
  4. Choi, Y. H., J. H. Kweon (2011), "Investigation of al-hydroxide precipitate fouling on the nanofiltration membrane system with coagulation pretreatment: effect of inorganic compound, organic compound, and their combination", Environmental Engineering Research, 16(3): 149-157. https://doi.org/10.4491/eer.2011.16.3.149
  5. Kurama, H., J. Poetzschke, R. Haseneder (2002), "The application of membrane filtration for the removal of ammonium ions from potable water", Water Research, 36: 2905-2909. https://doi.org/10.1016/S0043-1354(01)00531-0
  6. Nicolaisen, B. (2003), "Developments in membrane technology for water treatment", Desalination, 153: 355-360. https://doi.org/10.1016/S0011-9164(02)01127-X
  7. Oh, J. I., K. Yamamoto (2009), "Development of transport parameters affecting on the removal of micro organic compounds such as disinfection by-products and pharmaceutically active compounds by low-pressure nanofiltration, Environmental Engineering Research, 14(2): 126-133. https://doi.org/10.4491/eer.2009.14.2.126
  8. Oh, J. I., S. H. Lee, K. Yamamoto (2004), "Relationship between molar volume and rejection of arsenic species in ground water by low-pressure nanofiltration process", Journal of Membrane Science, 234: 167-175. https://doi.org/10.1016/j.memsci.2004.01.023
  9. Oh, J. I., T. Urase (2011), "Evaluation of the effective charge density on low pressure nanofiltration with the separation characteristics of monovalent and divalent solutes in the production of drinking water", Environmental Engineering Research, 16(1): 29-34. https://doi.org/10.4491/eer.2011.16.1.029
  10. Rahimpour, A., M. Jahanshahi, N. Mortazavian, S. S. Madaeni, Y. Mansourpanah (2010), "Preparation and characterization of asymmetric polyethersulfone and thin-film composite polyamide nanofiltration membranes for water softening", Applied Surface Science, 256(6): 1657-1663. https://doi.org/10.1016/j.apsusc.2009.09.089
  11. Rautenbach, R., T. Linn (1996), "High pressure reverse osmosis and nanofiltration, a "zero discharge" process combination for treatment of wastewater with severe fouling and scaling potential", Desalination, 105: 63-70. https://doi.org/10.1016/0011-9164(96)00059-8
  12. Slesarenko, V. V. (2003), "Electrodialysis and reverse osmosis membrane plants at power stations", Desalination, 158: 311.
  13. Wang, X. L., W. J. Shang, D. X. Wang, L. Wu, C. H. Tu (2009), "Characterization and applications of nanofiltration membranes: State of the art", Desalination, 236(1-3): 316-326. https://doi.org/10.1016/j.desal.2007.10.082