Environmental remediation through sequestration in surfactant micelles followed by sequestration in mesoporous materials

ENVR 40

Jia Zhou, vj@tulane.edu1, Dimitrios Vavlekas1, Grace Tan1, Mohit Singh1, Christy D. Ford, cford1@tulane.edu1, Kevin McCarthy2, Gary L. McPherson3, JiBao He4, and Arijit Bose, bosea@egr.uri.edu5. (1) Department of Chemical and Biomolecular Engineering, Tulane University, 6823 St. Charles Ave., New Orleans, LA 70118, (2) Department of Chemistry, Hamilton College, 198 College Hill Road, Clinton, NY 13323, (3) Department of Chemistry, Tulane University, 6823 St. Charles Ave., New Orleans, LA 70118, (4) Coordinated Instruments Facility, Tulane University, 6823 St. Charles Ave., New Orleans, LA 70118, (5) Department of Chemical Engineering, University of Rhode Island, 16 Greenhouse Road, Room No: 217 Crawford Hall, Department of Chemical Engineering, Kingston, RI 02881
Many ubiquitous pollutants in aqueous systems (chlorinated hydrocarbons, phenols, etc.) can be removed quite efficiently by entrapment in surfactant micelles through the well-studied membrane-enhanced ultrafiltration process (MEUF). It is the common assumption that spherical micelles swell upon uptake of the pollutants. We show that uptake of specific pollutants (particularly phenols) results in a dramatic shape change of micelles from spherical to wormlike and vesicular structures. We have developed a facile follow-up method where the entrapped species in surfactant microstructures become encapsulated in mesoporous silicas. The pollutant is, therefore, highly concentrated with a volume reduction of several orders-in-magnitude and converted to solid materials for easy disposal. But, additionally, the process results in the generation of functional mesoporous materials. The fundamentals of such entrapment and encapsulation are studied through a combination of small angle neutron scattering, cryo-transmission electron microscopy and X-ray diffraction. There are remarkable modulations in micelle characteristics upon entrapment, with transitions from spherical micelles to wormlike micelles and, thence, to spherical vesicles and eventually to wormlike vesicles. These structures which are then used as templates for ceramic synthesis, create modifications in ceramic mesoporosity which are correlated to the characteristics of self-assembly.
 

Advances in Adsorption Processes for Drinking Water Treatment and Sourcewater Protection
1:30 PM-5:10 PM, Sunday, April 6, 2008 Morial Convention Center -- Rm. 236, Oral

Division of Environmental Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008