Adsorption of Chlorinated Phenols from Aqueous Solution By Surfactant-Modified Pillared Clays
New pillared clay-based adsorbents have been prepared by incorporating a nonionic surfactant of general formula C12–14H25–29O(CH2CH2O)5H (commercial name, Tergitol 15S-5), during the synthesis of the aluminum hydroxide pillaring reagent. Different loadings of surfactant have been examined. The presence of the surfactant enhanced the adsorption capacity of the clay toward 3-monochlorophenol from aqueous solution. On the basis of adsorption results for a series of clays with increasing surfactant loadings, the best adsorbent was obtained at a surfactant loading of 255 mg/g of clay. At this loading, the surfactant occupies the micropores, as well as the mesopores and the external surfaces of the pillared clay. Analysis of the adsorption isotherms for 3-monochlorophenol, 3,5-dichlorophenol, 3,4,5-trichlorophenol and pentachlorophenol at different pH shows that the most energetic adsorption sites are the surfactant-occupied micropores between pillars. Additional binding of chlorinated phenols occurs at surfactant sites on external surfaces and mesopores. Upon calcination at 500°C, the clay is converted to a conventional alumina-pillared clay with a basal spacing near 16 Å. This calcined product can be reused as an adsorbent for chlorinated phenols by readsorbing fresh surfactant. The recycled adsorbent exhibits performance properties comparable to the original adsorbent. These results demonstrate the feasibility of utilizing a surfactant-modified pillared clay as a recyclable adsorbent and combustion catalyst for environmental pollutants.
Key WordsAdsorption Alumina-pillared clay Chlorinated phenols Tergitol
Unable to display preview. Download preview PDF.
- Boyd, S. A. and Mikeseil, M. (1989) Reactions of chlorophenols in soils: in Reactions and Movements of Organic Chemicals in Soils, B. L. Sawhney, ed., Soil Science Soc. Amer. Spec. Pub., Madison, Wisconsin, 209–228.Google Scholar
- Cases, J. M. (1979) Adsorption des tensio-actifs à l’interface solide-liquide: Thermodynamique et influence de l’hétéro-généité des adsorbants: Bull. Mineral. 102, 684–707.Google Scholar
- Chapman, P. M., Romberg, G. P., and Vigers, C. A. (1982) Design of monitoring studies for priority pollutants: J. Water Pollution Control Fed. 54, 292–297.Google Scholar
- Fahey, D. R., Williams, K. A., Harris, R. J., and Stapp, P. R. (1989) Preparation of pillared clay: U.S. Patent 4 845 066.Google Scholar
- Guymont, F. J. (1980) in Activated Carbon Adsorption of Organics from the Aqueous Phase Vol. 2, I. H. Suffet and M. J. McGuire, eds. Ann Arbor Science, Ann Arbor, Michigan, Ch. 23.Google Scholar
- Landau, S. D. (1984) Physical and catalytic properties of hydroxy-metal interlayered smectite minerals: Ph.D. thesis, Michigan State University, East Lansing, Michigan.Google Scholar
- McBride, M. B., Pinnavaia, T. J., and Mortland, M. M. (1977) Adsorption of aromatic molecules by clays in aqueous suspension: Adv. Environ. Sci. Technol. 8, 145–154.Google Scholar
- Mortland, M. M. (1986) Mechanisms of adsorption of non-humic organic species by clays: in Intercations of Soil Minerals with Natural Organics and Microbes, P. M. Huang, and M. Schnitzer, eds. Soil Sci. Soc. Amer., Madison, Wisconsin, 59–76.Google Scholar
- Suffet, I. H., and McGuire, M. J. (1980) Activated Carbon Adsorption of Organics from the Aqueous Phase: Ann Arbor Science, Ann Arbor, Michigan.Google Scholar
- Theng, B. K. G. (1974) The Chemistry of Clay-Organic Reactions: Wiley, New York, 343 pp.Google Scholar
- Wolf, T. A., Demirel, T., and Baumann, R. E. (1986) Adsorption of organic pollutants on montmorillonite treated with amines: J. Water Pollution Control Fed. 58, 68–76.Google Scholar