Credit: © 2008 ACS

Owing to their energy efficiency, the market for fluorescent lighting is rapidly growing. However, these lamps contain mercury, which is a well-known toxicant, especially for the neural development of young children. Although an individual lamp contains far less mercury than some household devices, such as a thermometer, the increasing production and low recycling rates have motivated researchers at Brown University to use nanomaterials to manage the exposure and capture of mercury vapour from damaged lamps.

Robert Hurt and colleagues1 first simulated a cleanup by measuring the amount of mercury vapour released from broken fluorescent lamps. New bulbs released up to 1.3 mg (30% of the total mercury) over four days whereas older bulbs showed similar profiles but released smaller amounts. When nanoscale formulations of sulphur, zinc, nickel, copper, silver, various metal sulphides, carbon and selenium were compared with their microscale counterparts for efficiency in absorbing mercury vapour, nano-selenium and nano-silver absorbed most effectively. Both required less than 1 g of material (compared with 10 g for the other metals) to absorb 1 mg of mercury vapour typically released by these lamps, making them attractive for consumer packaging.

Although the absorption capacity of nano-selenium and nano-silver still needs to be improved, they are potentially useful for various cleanup, disposal, recycling and packaging applications.