Poison Control: Removing arsenic with reusable nanofibers

A carcinogenic heavy metal, arsenic can leach into groundwater through both natural and man-made processes. At least 140 million people in 50 countries have been exposed to drinking water contaminated with arsenic. Current methods of arsenic removal typically involve two key steps: conversion of arsenic to a less toxic and more easily removable state followed by absorption of the arsenic. These methods can be time-, energy-, and resource-intensive, and they often seep nanomaterials into the environment.

This spring, however, fifth-year Ph.D. candidate in Yale’s Department of Chemical and Environmental Engineering Camrynn Fausey revolutionized the way arsenic is removed from water. Through a process called electrospinning, Fausey used chitosan, a waste product from the fishing industry, to create nanofibers. She then coated the nanofibers in titanium dioxide (TiO2)—a compound that converts arsenic to a less toxic state—and reduced graphene oxide—a compound that significantly improves the performance of TiO2.

Together, the nanofibers and compounds simultaneously convert and adsorb arsenic, transforming the two-step process into a one-step process. Since the nanofibers, built like small fabric mats, can easily be moved to new batches of contaminated water, Fausey’s nanofibers are easy-to-use, resource-efficient, and reusable. Finally, because TiO2 is attached to the nanofibers, the issue of nanomaterial leaching into the environment is resolved too.

Now that she has the technology to remove arsenic from water more efficiently, Fausey plans on adapting the same technology to remove other contaminants in water, such as mercury. When asked about the goals of her research, Fausey responded, “To see nanotechnology used to benefit the lives of others around the world, specifically in the realm of nanotechnology-enabled water treatment.”