A controllable Fe0–C permeable reactive barrier for 1,4-dichlorobenzene dechlorination

A controllable Fe0–Granular Activated Carbon (GAC) process was designed to adjust the Fe0 corrosion speed and to fully utilize the electrons generated by the reaction pair via dual electrode reduction. The innovative concept behind the design is that the micro-electrolytic cells would be modified by positioning the Fe0 chamber and GAC chamber separately and connecting the two chambers only by external conducting circuit. The design would prevent the excessively spontaneous corrosion of Fe0 which shortens the permeable reactive barrier (PRB) life span, and the system performance could be manipulated based on the actual concentrations of the contaminants via controlling the current generated by the Fe0–GAC pair. Following results are obtained using this modified process: (1) it was found out that 1,4-dichlorobenzene (1,4-DCB) could be efficiently dechlorinated in both anode and cathode chamber under experimental conditions proved by IC, which verifies that the electrons produced in the anode chamber reaction Fe2+→Fe3++e-Fe2+→Fe3++e- could be further utilized for contaminant dechlorination; (2) the corrosion speed of the Fe0 could be controlled by manipulating the conductivity of the external circuit; (3) it was also proved that the long term performance of the process was significantly better than that of the Fe0 PRB because the surface clogging and over consumption of the Fe0 could be effectively avoided as shown by SEM and XRD; (4) the research showed that the iron efficiency (IE) of the proposed setup was averagely 225.7% higher than that of the conventional Fe0 PRB design. These results manifests that the proposed design is promising and has a potential for application in the treatment of wastewater containing chlorinated organics.

► A novel controllable Fe0–GAC process was designed to improve conventional PRB.
► This would prevent the excessive corrosion of Fe0 via controlling the current.
► 1,4-DCB could be efficiently dechlorinated in both anode and cathode chamber.
► The iron efficiency of the setup was averagely 225.7% higher vs. traditional.