Reclaiming mercury from spent fluorescent bulbs | Chemical & Engineering News
Volume 94 Issue 17 | p. 10 | Concentrates
Issue Date: April 25, 2016

Reclaiming mercury from spent fluorescent bulbs

New process might offer a more energy-efficient alternative to current recycling methods
By Melissa Pandika, special to C&EN
Department: Science & Technology
News Channels: Environmental SCENE, Materials SCENE, Nano SCENE
Keywords: environment, sustainability, nanomaterials, mercury, fluorescent, light bulb, energy efficient, nanoparticles, recycling

Removing and reusing mercury from spent compact fluorescent lightbulbs helps keep the toxic element out of landfills, where it can enter the environment. In an effort to advance mercury recycling, researchers have developed a technique for processing spent CFLs that’s more energy efficient than current methods (ACS Sustainable Chem. Eng. 2016, DOI: 10.1021/acssuschemeng.5b01612). Existing recovery methods evaporate mercury at high temperature, separating it from other materials in the bulbs. Parisa A. Ariya of McGill University and her colleagues instead use iron oxide nanoparticles to trap mercury at near room temperature without heating. The team broke open CFLs within a vessel that was connected to a chamber loaded with nanoparticles. As mercury vapor from the bulbs flowed into the chamber, it stuck to the nanoparticles. The team then used magnets to transfer the nanoparticles to an electrochemical reactor in which the researchers drove off ionic mercury species and reduced them to elemental mercury. Their prototype system recovered up to 85% of the mercury and required only 20 W of power, little enough for a small solar panel to provide.

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In a new recycling process, magnetic Fe3O4 nanoparticles remove mercury vapor from spent fluorescent bulbs, followed by electrochemical separation to pull the mercury off the nanoparticles for reuse.
Credit: ACS Sustainable Chem. Eng.
Schematic of two-step mercury recovery process from light bulbs.
 
In a new recycling process, magnetic Fe3O4 nanoparticles remove mercury vapor from spent fluorescent bulbs, followed by electrochemical separation to pull the mercury off the nanoparticles for reuse.
Credit: ACS Sustainable Chem. Eng.
 
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