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Graphene-Based Microbots for Toxic Heavy Metal Removal and Recovery from Water
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posted on 2016-03-21, 00:00 authored by Diana Vilela, Jemish Parmar, Yongfei Zeng, Yanli Zhao, Samuel SánchezHeavy
metal contamination in water is a serious risk to the public
health and other life forms on earth. Current research in nanotechnology
is developing new nanosystems and nanomaterials for the fast and efficient
removal of pollutants and heavy metals from water. Here, we report
graphene oxide-based microbots (GOx-microbots) as active self-propelled
systems for the capture, transfer, and removal of a heavy metal (i.e.,
lead) and its subsequent recovery for recycling purposes. Microbots’
structure consists of nanosized multilayers of graphene oxide, nickel,
and platinum, providing different functionalities. The outer layer
of graphene oxide captures lead on the surface, and the inner layer
of platinum functions as the engine decomposing hydrogen peroxide
fuel for self-propulsion, while the middle layer of nickel enables
external magnetic control of the microbots. Mobile GOx-microbots remove
lead 10 times more efficiently than nonmotile GOx-microbots, cleaning
water from 1000 ppb down to below 50 ppb in 60 min. Furthermore, after
chemical detachment of lead from the surface of GOx-microbots, the
microbots can be reused. Finally, we demonstrate the magnetic control
of the GOx-microbots inside a microfluidic system as a proof-of-concept
for automatic microbots-based system to remove and recover heavy metals.