Removal of Heavy Metals and Organic Contaminants from Aqueous Streams by Novel Filtration Methods
The removal of hazardous waste, generated by the dismantling of nuclear weapons is a problem that requires urgent attention by the US Department of Energy. Low levels of radioactive contaminants combined with organic solvent residues have leaked from aging containers into the soil and underground water in the surrounding area. Due to the complexity of the problem, it is evident that traditional adsorption methods are ineffective, since the adsorbent tends to saturate with the aqueous component. It has become apparent that a much more aggressive approach is required which involves the use of specially designed materials. We have investigated the potential of solids that combine high surface area/high pore volume and high electrical conductivity, a rare combination of properties found in a single material. In this program we examined the potential of newly developed materials for the trapping of organic solvents within specially engineered cavities without allowing the material to become saturated with water. Catalytically grown carbon nanofibers are a set of novel structures that are produced by the decomposition of selected carbon-containing gases over metal particles. These materials consist of extremely small graphite platelets stacked in various orientations with respect to the fiber axis. Such an arrangement results in a unique structure that is composed of an infinite number of extremely short and narrow pores, suitable for sequestering small molecules. In addition, when the graphene layers are aligned parallel to the fiber axis, an unusual combination of high surface area and low electrical resistivity solids are attained. We have attempted to capitalize on this blend of properties by using such structures for the selective removal of organic contaminants from aqueous streams. Experimental results indicate that nanofibers possessing a structure in which the graphite platelets are aligned perpendicular to the fiber axis and possessing a high degree of structural perfection exhibit superior selective adsorption properties with respect to removal of alcohols from aqueous medial over that displayed by active carbon. Furthermore, we have attempted to take advantage of the high electrical conductivity as well as the high availability of edges, and we have used these materials for the removal of metal ions from solution. Preliminary results indicate that graphite nanofibers can, in the presence or absence of an applied electric field, capture metal ions from solution. In addition, it has been found that certain types of nanofibers can absorb substantial amounts of water both in the vapor and liquid phase.
- Research Organization:
- USDOE Idaho Operations Office, Idaho Falls, ID; Northeastern University, Boston, MA (US)
- Sponsoring Organization:
- USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- FG07-96ER14688
- OSTI ID:
- 765175
- Report Number(s):
- DOE/ER/14688; TRN: US0100220
- Resource Relation:
- Other Information: PBD: 1 Aug 2000
- Country of Publication:
- United States
- Language:
- English
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Removal of Metallic and Organic Contaminants from Aqueous Streams by Novel Filtration Methods
Removal of heavy metals and organic contaminants from aqueous streams by novel filtration methods. 1998 annual progress report
Related Subjects
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
ELECTRIC CONDUCTIVITY
ELECTRIC FIELDS
FILTRATION
NUCLEAR WEAPONS
ORGANIC SOLVENTS
REMOVAL
SURFACE AREA
RADIOACTIVE CONTAMINANTS
ORGANIC SOLVENT RESIDUES
SOIL
WATER
CARBON NANOFIBERS
GRAPHITE PLATELETS
FIBER AXIS
ELECTRICAL RESISTIVITY
AQUEOUS STREAMS
ADSORPTION