Extramural Research
Presentation Abstract
Grantee Research Project Results
Title of Talk:
Nanoscale Biopolymers With Tunable Properties for Improved Decontamination and Recycling of Heavy Metals
Abstract of Talk:
Heavy metal ions are major sources for pollution of the biosphere and
they are usually found as co-contaminants in many superfund sites. Current
technologies are inadequate to reduce metal concentrations to acceptable
standards and to separate these heavy metals from a waste mixture for
potential recycling. Our goal in this work is to develop a technology
utilizing nanoscale metal-binding biopolymers with customizable properties
for the differential sequestration and recovery of different heavy metals
in a mixed-metal waste. Tunable biopolymers based on elastin-like polypeptides
(ELP) will be generated to demonstrate this feasibility by specifically
incorporating different metal binding domains into ELP biopolymers with
dramatically different transition temperatures. Initial feasibility studies
will utilize two different ELP building blocks containing either polyhistidine
or synthetic phytochelatin as the metal-binding domain. Application of
this technology for soil remediation will also be discussed. This technology
serves as an example to provide an efficient and non-toxic solution to
the removal and separation of heavy metal contamination.
Environmental Applications/Implications:
The biosynthetic approach is environmentally friendly and allows precise
and independent control of the length, composition, and charge density
of the interacting end blocks and metal-binding domains, thus allowing
the flexibility in designing tunable biopolymers that can undergo transition
from water-soluble into aggregate forms under a wild-range of conditions
and such precise control is valuable to satisfy the needs of different
process conditions. Comparing to conventional chemical chelators or chelating
polymers, the proposed biopolymers is environmentally friendly since no
toxic chemical is required for their synthesis and regeneration can be
achieved easily. This strategy if successful, will provide a low-cost
and environmentally benign technology for heavy metal removal.
Success Stories:
A new paper describing the use of a mercury-specific biopolymer for the
selective removal of mercury from contaminated water has just appeared
in Environmental Science and Technology. This new technology has been
highlighted by Science News and by the Technology Solution section of
Environmental Science and Technology.