Advanced Separation Systems for Adsorption and Filtration of Environmental Contaminants

As regulations governing environmental water pollution are enacted, the demand for improved remediation technologies and related materials must be addressed. Some of the most problematic pollutants are the volatile organic contaminants (VOCs) because of their high mobility through soils and into aquifers, and their resistance to biodegradation. Some of the most ubiquitous of these chemicals include trichloroethylene (TCE), chloroform, and methyl tert-butyl ether (MTBE) due to their prolific use in the metals finishing, dry-cleaning, water treatment and reformulated gasoline industries. In the present study, activated carbon fiber assemblies (ACFAs) were developed and tailored to adsorb these contaminants and improve upon the current industry standard of activated carbon granules (ACGs) while remaining cost competitive. These new materials have higher surface areas, faster adsorption rates due to improved contact efficiencies, and in situ regeneration capability through electrical resistance heating when compared with ACGs. Advantage is taken of flexible fabrication techniques to tailor porosity and surface chemistry for the specific removal of TCE, chloroform and MTBE from water. The surface area, microporosity, and surface chemistry of ACFA coatings were monitored through the use of TGA, BET N2 adsorption, elemental analysis, and XPS equipment while aqueous VOC concentrations were analyzed using a purge &trap GC. Static and dynamic adsorption evaluations displayed a major improvement over ACGs and the contaminated ACFAs also demonstrated the ability to be regenerated under relatively mild conditions.