title: Development of KMnO(4)-releasing composites for in situ chemical oxidation of TCE-contaminated groundwater.
abstract: 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 = 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 effluents 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 reaction-diffusion 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.
authors.affiliation: Taiwan VCM Co., Kaohsiung 832, Taiwan.
authors.forename: S H
authors.initials: SH
authors.lastname: Liang
authors.affiliation: Department of Civil Engineering, National Chi Nan University, Nantou County, Taiwan.
authors.forename: K F
authors.initials: KF
authors.lastname: Chen
authors.affiliation: Department of Chemical and Biochemical Engineering, Kao Yuan University, Kaohsiung, Taiwan.
authors.forename: C S
authors.initials: CS
authors.lastname: Wu
authors.affiliation: Department of Chemical and Biochemical Engineering, Kao Yuan University, Kaohsiung, Taiwan.
authors.forename: Y H
authors.initials: YH
authors.lastname: Lin
authors.affiliation: Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan. Electronic address: jkao@mail.nsysu.edu.tw.
authors.forename: C M
authors.initials: CM
authors.lastname: Kao
mesh_terms: D004000:Dichloroethylenes / Q000737:chemistry; D004553:Electric Conductivity; D060587:Groundwater / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D017895:Manganese Compounds / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry; D010100:Oxygen / Q000032:analysis; D011196:Potassium Permanganate / Q000737:chemistry*; D012987:Soil / Q000737:chemistry; D014241:Trichloroethylene / Q000737:chemistry*; D014752:Vinyl Chloride / Q000737:chemistry; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D004000:Dichloroethylenes; D017895:Manganese Compounds; D010087:Oxides; D012987:Soil; D014874:Water Pollutants, Chemical; D011196:Potassium Permanganate; C029297:vinylidene chloride; D014241:Trichloroethylene; D010100:Oxygen; C016552:manganese dioxide; D014752:Vinyl Chloride; C035384:1,2-dichloroethylene
keywords: Groundwater contamination; In situ chemical oxidation; Potassium permanganate; Potassium permanganate releasing composite; Trichloroethene