Remediation of TCE-contaminated groundwater using acid/BOF slag enhanced chemical oxidation

The objective of this study was to evaluate the potential of applying acid/H2O2/basic oxygen furnace slag (BOF slag) and acid/S2O82-/BOF slag systems to enhance the chemical oxidation of trichloroethylene (TCE)-contaminated groundwater. Results from the bench-scale study indicate that TCE oxidation via the Fenton-like oxidation process can be enhanced with the addition of BOF slag at low pH (pH = 2–5.2) and neutral (pH = 7.1) conditions. Because the BOF slag has iron abundant properties (14% of FeO and 6% of Fe2O3), it can be sustainably reused for the supplement of iron minerals during the Fenton-like or persulfate oxidation processes. Results indicate that higher TCE removal efficiency (84%) was obtained with the addition of inorganic acid for the activation of Fenton-like reaction compared with the experiments with organic acids addition (with efficiency of 10–15% lower) (BOF slag = 10 g L−1; initial pH = 5.2). This could be due to the fact that organic acids would compete with TCE for available oxidants. Results also indicate that the pH value had a linear correlation with the observed first-order decay constant of TCE, and thus, lower pH caused a higher TCE oxidation rate.

Research highlights
► The acid/H2O2 and persulfate/basic oxygen furnace slag system has been developed.
► The system can be used to enhance TCE oxidation via Fenton-like or persulfate oxidation processes.
► BOF slag was used as the iron and catalytic source during the Fenton-like and persulfate oxidation processes.
► This design can be converted to a permeable reactive barrier system for groundwater remediation.