The objective of this study was to develop a controlled-oxidant-release technology
combining in situ chemical oxidation (ISCO) and permeable reactive barrier (PRB) concepts to
remediate trichloroethene (TCE)-contaminated groundwater. In this study, a potassium
permanganate (KMnO4)-releasing composite (PRC) was designed for KMnO4 release. The
components of this PRC included polycaprolactone (PCL), KMnO4, and starch with a weight
ratio of 1.14:2:0.96. Approximately 64% (w/w) of the KMnO4 was released from the PRC after 76
days of operation in a batch system. The results indicate that the released KMnO4 could
oxidize TCE effectively. The results from a column study show that the KMnO4 released from
200 g of PRC could effectively remediate 101 pore volumes (PV) of TCE-contaminated
groundwater (initial TCE concentration ¼ 0.5 mg/L) and achieve up to 95% TCE removal.
The effectiveness of the PRC system was verified by the following characteristics of the ef-
fluents collected after the PRC columns (barrier): (1) decreased TCE concentrations, (2)
increased ORP and pH values, and (3) increased MnO2 and KMnO4 concentrations. The results
of environmental scanning electron microscope (ESEM) analysis show that the PCL and
starch completely filled up the pore spaces of the PRC, creating a composite with low porosity.
Secondary micro-scale capillary permeability causes the KMnO4 release, mainly through a
reactionediffusion mechanism. The PRC developed could be used as an ISCO-based passive
barrier system for plume control, and it has the potential to become a cost-effective alternative
for the remediation of chlorinated solvent-contaminated groundwater