Environmental Engineering Reference
In-Depth Information
treatments offer a new realm of research similar to medical research being conducted
for use of polymers for drug delivery and human implants. One of the major consid-
erations however is the cost for biodegradable polymers. Many major biodegradable
polymer producers have stopped or limited production of their biodegradable poly-
mers brands due to the higher cost for the use of a biodegradable polymer compared
to traditional polymeric materials.
Controlled release methods for environmental engineering can have a wide-
spread impact as alternative chemicals are considered for use in extended remedia-
tion. The delivery of solid oxidants from a degradable shell has several advantages.
(1) It stabilizes the solid oxidants for emplacement in the subsurface to form per-
meable reactive barriers, packed in a series of wells where contaminated water will
flow past the pellets for remediation, or packed in a reactor for a pump and treat
system. (2) It reduces the need for maintenance associated with the gaseous and
liquid oxidants. (3) It reduces the dangers associated with handling the oxidant by
workers. (4) It extends the release of an oxidant without the need to re-inject the
gas or liquid solutions. Preliminary results support the potential for this technol-
ogy in environmental engineering remediation. The possible applications of this
technology include use of the prototypes to form permeable reactive barriers. Such
barriers have been shown to be effective in recent remediation studies using zero-
valent iron [30, 31]. Packing screened wells in a treatment wall helps diffuse the
chemical oxidants in contaminated plumes. This technology will also work well in
a reactor system to treat contaminated effluent or as a pump-and-treat technique for
remediation. We are interested in exploring both subsurface, surface water, and land
application uses for the technology.
Our future work for using chemical oxidants encapsulated in biodegradable
polymers will include exploring alternative chemicals for encapsulation and investi-
gating alternative hydrophobic and hydrophilic polymer blends to control degrada-
tion rates for the polymer/chemical pellets. We will investigate optimization of the
chemical to polymer ratio, controlling and modeling chemical diffusion from poly-
mer shells, encapsulation methods (i.e. micro-based and nano-based), and structure
geometry. In particular, we are interested in exploring the use of alternative oxi-
dants for treatment of environmental contaminants including various groundwater
contaminants, pathogens, and pesticides.
Acknowledgements
We would like to thank our funding sources NSF Small Grants for Explo-
ratory Research (SGER Grant #0640035) and NSF Broadening Participation in Engineering
(BRIGE Grant # 0831631). We would also like to thank John Carver, and Bryce Holmes in the
North Carolina A&T State University Analytical Chemistry Lab for their assistance with this
research.
References
1. Segal M. (1991) Patches, pumps, and timed release: new ways to deliver drugs.
FDA
Consumer
, 25(8), 13-15.
2. Vert M. (2005) Aliphatic polyesters: great degradable polymers that cannot do everything.
Biomacromolecules
, 6(2), 538-546.
