Reductive dechlorination of trichloroethylene by polyvinylpyrrolidone stabilized nanoscale zerovalent iron particles with Ni.

We developed a novel stabilized nanoscale zerovalent iron (NZVI) particles with Ni using an electron conducting polymer, polyvinylpyrrolidone (PVP), to selectively dechlorinate trichloroethylene (TCE) to non-toxic intermediates. The size of the PVP stabilized NZVI-Ni ((PVP-NZVI-Ni), average diameter: ∼20nm) is smaller than that of bare NZVI (50-80nm) due to the prevention of agglomeration of the resultant iron particles by PVP. PVP-NZVI-Ni showed a complete removal of TCE in 1h with superior dechlorination kinetics (k=5.702h) and ethane selectivity (98%), while NZVI-Ni showed 5 times slower dechlorination kinetics (1.218h). Other PVP-NZVI-metals (i.e., Cu, Sn, Co, and Mn) also enhanced the TCE dechlorination, but they were much slower (k=0.024-0.411h) than that of PVP-NZVI-Ni. In column test, PVP-NZVI-Ni exhibited better mobility (95% of PVP-NZVI-Ni recovery in the eluent) than NZVI-Ni (1%). In addition, PVP-NZVI-Ni reductively transform TCE to ethane even under 10 cycles of repeated TCE dechlorination treatment.