Resources Recycling (자원리싸이클링)

The Korean Institute of Resources Recycling (한국자원리싸이클링학회)
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A Study on the Sol-Gel Reaction Kinetics of Sodium Silicate Solution

규산(硅酸)나트륨 수용액(水溶液)의 솔-젤 반응속도론적(反應速度論的) 고찰(考察)

  • Kim, Chul-Joo (Division of Minerals Utilization and Materials, Korea Institute of Geoscience and Mineral Resources) ;
  • Yoon, Ho-Sung (Division of Minerals Utilization and Materials, Korea Institute of Geoscience and Mineral Resources) ;
  • Jang, Hee-Dong (Division of Minerals Utilization and Materials, Korea Institute of Geoscience and Mineral Resources)
  • 김철주 (한국지질자원연구원 자원활용소재연구부) ;
  • 윤호성 (한국지질자원연구원 자원활용소재연구부) ;
  • 장희동 (한국지질자원연구원 자원활용소재연구부)
  • Published : 2008.12.27
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Abstract

The properties of sodium silicate solution were surveyed by using the yellow silicomolybdic method, and the formation of silica sol from sodium silicate solution and the growth of silica sol were investigated in this study. The $SiO_2$ content of 2 wt% in sodium silicate solution was proper to oxidize sodium silicate with sulfuric acid. After the removal of sodium ions in sodium silicate solution, the pH of silicate solution had to be controlled above 9 for the stabilization of silicate solution. The condensation between silicic acid species and silica nuclei surfaces has been studied at $20{\sim}80^{\circ}C$ and pH 10 in silicate solutions with silica nuclei. The reaction falls into two kinetics regimes, limited at high silicic acid species concentration by polymerization, but at lower concentration by a process whereby deposited silicic acid species condenses further to silica. The overall condensation is first-order in silicic acid species concentration, proceeded toward to pseudo equilibrium concentration, $C_x$, rather than the solubility of amorphous silica. The heat of solution of amorphous silica was 3.34 kcal/mol and exhibits an Arrhenius temperature dependence with an apparent activation energy of 3.16 kcal/mol in the range of $20{\sim}80^{\circ}C$.

본 연구에서는 yellow silicomolybdate method를 이용하여 규산나트륨 수용액의 특성, 핵 생성에 필요한 규산나트륨 수용액의 산화반응 특성 그리고 출발용액의 솔젤 반응특성을 기초로 하여 실리카 솔 형성에 대한 반응속도론적 고찰을 하였다. $SiO_2$를 2wt% 함유한 규산나트륨 수용액은 황산으로 산화시키기에 적당하였으며, 규산나트륨 수용액중의 나트륨 이온을 제거한 후, 안정된 실리 케이트 수용액을 얻기 위한 용액의 pH는 9 이상이었다. 규산종과 실리카 핵 표면 사이의 축중합 반응에 관한 속도론적 연구는 반응온도 $20{\sim}80^{\circ}C$, 수용액의 pH 10에서 수행하였다. 반응은 두 영역으로 구분되는데, 규산종의 농도가 높은 영역에서는 축중합 반응에 의해 제한을 받으며, 낮은 농도 영역에서는 화학흡착된 규산종이 실리카로 응축되는 공정에 영향을 미친다. 전체 축중합 반응은 규산종 농도의 1차 반응으로 진행되며, 축중합 반응은 무정형 실리카의 용해도에 접근하기 보다는 가평형점($C_x$) 향하여 진행된다. 본 연구조건에서 무정형 실리카의 용해열은 3.34 kcal/mol이었고 축중합 반응의 활성화에너지는 3.16 kcal/mol이었다.

Keywords

References

  1. Iler, R. K., 1979 : The Chemistry of silica, John Wiley & Sons Inc., New York
  2. Kirk-Othmer, 1982 : Encyclopedia of Chemical Technology, John Wiley & Sons Inc., New York
  3. Lee, M. H. et al., 2005 : Nanostructured sorbents for capture of cadmium species in combustion environments, Environ Sci Technol., 39, pp. 8481-8489 https://doi.org/10.1021/es0506713
  4. Lu, Y. F. et al., 1999 : Aerosolassisted self-assembly of mesostructured spherical nanoparticles, Nature, 398, pp. 223-226 https://doi.org/10.1038/18410
  5. Lenggoro, I. W. et al., 2000 : An experimental and modeling investigation of particle production by spray pyrolysis using a laminar flow aerosol reactor, J. Mater Res., 15, pp. 733-743 https://doi.org/10.1557/JMR.2000.0106
  6. Bergna, H. E., 1994 : The Colloid Chemistry of Silica, Ame. Chem. Soc., Washington DC
  7. Oh, M. H. et al., 1999 : Preparation of Silica Dispersion and its Phase Stability in the Presence of Salts, Korean J. Chem. Eng., 16, pp. 532-537 https://doi.org/10.1007/BF02698280
  8. Park, S. K., Kim, K. D., and Kim, H. T., 2000 : Synthesis of Monodisperse $SiO_2$ and $TiO_2$ Nanoparticles using Semibatch Reactor and Comparison of Parameters Effecting Particle Size and Particle Size Distribution, J. Ind. Eng. Chem., 6, pp. 365-364
  9. Gallardo, J. and Galloano, P. G., 2002 : Preparation and in vitro evaluation of porous silica gels, J. Biomaterials, 23, pp. 4277-4284 https://doi.org/10.1016/S0142-9612(02)00190-4
  10. Salvado, I. M. M., Sousa, J. S., and Margaca, F. M. A., 2000 : Structure of $SiO_2$ gels prepared with different water contents, J. Physica B., pp. 276-278
  11. Kim, S. W., Jang, J. S., and Kim, O. Y., 1998 : The rheological properties optimization of fumed silica dispersions using statistical experimental design and taguchi method, J. Polymer Testing, 17, pp. 225-235 https://doi.org/10.1016/S0142-9418(97)00044-5
  12. Yziquel, F., Carreau, P. J., and Tanguy, P. A., 1999 : Non-linear viscoelastic behavior of fumed silica suspensions, Rheol Acta., 38, pp. 14-25 https://doi.org/10.1007/s003970050152
  13. Iler, R. K., 1980 : Isolation and characterization of particle nuclei during the polymerization of silicic acid to colloidal silica, J. Coll. Int. Sci., 75, pp. 138-148 https://doi.org/10.1016/0021-9797(80)90357-4
  14. Coudurier, M. and Baudru, R., 1971 : Bull. Soc. Chim. Fr., 9, p. 3147
  15. Schlomach, J. and Kind, M., 2004 : Investigations on the semi-batch precipitation of silica, J. Colloid and Interface Sci., 277, pp. 316-326 https://doi.org/10.1016/j.jcis.2004.04.051
  16. Fleming, B. A., 1981 : Polymerization Kinetics and Ionization Equilibria in Aqueous Silica Solutions, Ph. D. dissertator. Prinston University
  17. Fleming, B. A., 1986 : Kinetics of Reaction between Silicic Acid and Amorphous Silica Surfaces in NaCl Solution, J. Colloid & Interface Sci., 110(1), pp. 40-64 https://doi.org/10.1016/0021-9797(86)90351-6
  18. Yates, D. E. and Healy, T. W., 1976 : The Structure of the Silica/Electrolyte Interface, J. Collloid Interfacee Sci., 55, pp. 9-19 https://doi.org/10.1016/0021-9797(76)90003-5