Nanomaterials May Help Clean Up the Environment

Researchers have presented an extensive analysis of the role of nanomaterials in environmental remediation and monitoring, which can be used to clean up toxins and bacteria from natural waters, wastewaters, and the air.

Nanomaterials’ unique properties allow them to remove pollutants from the environment. The extremely small size of nanomaterial particles, typically in the range between 1 and 100 nanometers (billionth of a meter), creates a large surface area in relation to their volume, which makes them highly reactive, compared to non-Nano forms of the same materials.

Silver, iron, gold, titanium oxides and iron oxides are some of the commonly used nanoscale metals and metal oxides cited by the researchers that can be used in environmental remediation. Silver nanoparticles, for example, can be effective antimicrobial agents and can treat wastewater containing bacteria, viruses, and fungi. Nanoscale titanium dioxide can also kill bacteria and disinfect water when activated by light.

The researchers point to studies that show that carbon nanomaterials are particularly suited to removing a broad range of pollutants. Carbon nanotube clusters are used to purify water by adsorbing bacteria that contaminate the water. Heavy metals, such as cadmium, as well as organic pollutants including benzene and 1, 2-dichlorobenzene can also be removed from water by carbon nanotube materials.

The researchers suggest that nanoparticles can be attached to host polymer materials, such as porous resins, cellulose, and silica, to reduce potential harm to human health and the environment derived from the release of nanoparticles into the environment. The nanoparticles fixed to the host material can be more easily removed and captured from wastewater. Nanoparticles, such as nanoscale zinc oxide, fixed in this way, are used to break down organochlorine pesticides, halogenated herbicides and azo dyes.

In addition to remediating pollution, nanoparticles can be used as sensors to monitor toxins, heavy metals and organic contaminants in land, air and water environments and have been found to be more sensitive and selective than conventional sensors. Sensor strips composed of nylon 6 nano-fiber nets are one example. These are used to detect formaldehyde, a toxic air pollutant widely used in the manufacture of household materials and building products. The yellow sensor strips turn red upon exposure to formaldehyde.

The researchers acknowledge that ongoing work is needed to further improve the shape, sizes, structures, functionality, and manufacturing of nanomaterials that show promise in cleaning up contaminants that enter water, land, and air environments from industries. A better understanding of the behavior of nanomaterials and their potential harm to the environment is also required.