Influence of nanoscale zero-valent iron on geochemical properties of groundwater and vinyl chloride degradation: A field case study.
A 200m(2) pilot-scale field test successfully demonstrated the use of nanoscale zero-valent iron (NZVI) for effective remediation of groundwater contaminated with chlorinated organic compounds in Taiwan within six months. Both commercially available and on-site synthesized NZVI were used. A well-defined monitoring program allowing to collect three-dimensional spatial data from 13 nested multi-level monitoring wells was conducted to monitor geochemical parameters in groundwater. The degradation efficiency of vinyl chloride (VC) determined at most of monitoring wells was 50-99%. It was found that the injection of NZVI caused a significant change in total iron, total solid (TS) and suspended solid (SS) concentrations in groundwater. Total iron concentration showed a moderate and weak correlation with SS and TS, respectively, suggesting that SS may be used to indicate the NZVI distribution in groundwater. A decrease in oxidation-reduction potential (ORP) values from about -100 to -400mV after NZVI injection was observed. This revealed that NZVI is an effective means of achieving highly reducing conditions in the subsurface environment. Both VC degradation efficiency and ORP showed a correlative tendency as an increase in VC degradation efficiency corresponded to a decrease of ORP. This is in agreement with the previous studies suggesting that ORP can serve as an indicator for the NZVI reactivity.
Graduate Institute of Environmental Engineering, National Taiwan University, Taipei, Taiwan, ROC.
Yu-Ting
YT
Wei
Shian-Chee
SC
Wu
Chih-Ming
CM
Chou
Choi-Hong
CH
Che
Shin-Mu
SM
Tsai
Hsing-Lung
HL
Lien
D006843:Hydrocarbons, Chlorinated / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000458:organization & administration*; D013624:Taiwan; D014752:Vinyl Chloride / Q000737:chemistry*; D014872:Water Movements
D006843:Hydrocarbons, Chlorinated; D014752:Vinyl Chloride