Environmental Engineering Reference
In-Depth Information
Polymer Erosion
Polymer dissolves or degrades slowly in the
presence of water or due to microbial action
Released oxidant molecules
available to dissolve and react
Embedded or encapsulated oxidant
retained until further erosion of the
polymer
Diffusion Polymer
Moderately soluble polymer shell with
small pore openings created by water flow
or microbes (degradation) OR semi-
permeable membrane
Oxidant molecules diffuse with water
flow into the environment to react
Oxidant treatment released and
polymer shell naturally
degrades over time
Combine Controld
A layering of delayed dissolution and diffusion
controlled mechanisms. Polymer dissolves or
degrades slowly in the presence of water
or due to microbial action
Second layer permits
diffusion of some but not all
oxidant molecules
Delayed dissolution leads
to the delayed release
of remaining oxidants
Fig. 2.1
Schematic for mechanisms influencing CRBP structure design (modified from Uhrich
et al. 1999)
able to degrade environmental contaminants. In current chemical oxidation meth-
ods, highly reactive liquids or gases are injected into a contaminated zone. Chemical
oxidants rapidly react to oxidize and breakdown subsurface contaminants to less
toxic byproducts. Examples of oxidants used in chemox include ozone gas, Fenton's
