Carbon Nanotubes for Environmental Protection

In 2004, US Environmental Protection Agency (EPA) announced that research was needed to identify opportunities and applications of nanoscale science and technology to address environmental problems (www.epa.gov). Three research topics were identified

• Environmental benign manufacturing and processing,

• Remediation/treatment,

Nanotechnology refers to the use of materials and structures of nanoscale dimensions. Nanotubes are relatively new but broadly studied materials in the nanotechnology field. Due to their outstanding mechanical, electronic and chemical properties, carbon nanotubes offer great promise of delivering new and improved environmental technologies as sensors and sorbent materials to detect and treat existing contaminants and prevent new pollution which is significant challenges to environmental scientists and engineers. Nanotubes, present as small particulate material, may also present environmental hazards in their own right. Clearly nanotechnology brings many opportunities and challenges that scientists have only just begun to explore.

Environmental control agencies, researchers and the general public are concerned about the increasing mobilization and release of trace elements to the environment. Substances of significant concern in the remediation of soils, sediment and ground water include heavy metals (e.g. mercury, lead, cadmium) and organic compounds (e.g. benzene, chlorinated solvents, and toluene). Although nanotubes have been applied to adsorb several kinds of trace contaminants, (Li et al. 2002, 2003a, b) from water, there is a lack of fundamental understanding of the physics and chemistry of nanotubes surfaces related to sorbent capacity, and interference of other components in the gas mixture.

Nanotechnology could make many products lighter, stronger, cleaner, less expensive and more accurate. Nanotechnology has the potential to significantly improve environmental protection (http://es.epa.gov/ncer/nano/index.html). Specifically carbon based nanostructures exhibit unique properties and morphological flexibility, which renders them as inherently multifunctional and compatible with organic and inorganic systems. Carbon nanotubes have aspect ratio on the order of 1,000, which coupled with high conductivity, makes them ideal candidates for low voltage emitters.

Carbon nanotubes are the building blocks of Nanotechnology and are shinning everywhere like a diamond because of their special physicochemical properties. Therefore, this review article is an attempt to explain the status of carbon nanotubes for environmental protection.

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