Comparison of trichloroethylene dechlorination in seawater by sulfidated nanoscale zero-valent iron particles prepared by two methods

Abstract

Sulfidated nanoscale zero-valent iron (S-nZVI) particles have demonstrated great potential in the remediation of trichloroethylene (TCE) due to their high reactivity and electron selectivity. However, very few studies have been carried out to investigate their application in salinity water or seawater. In this work, two kinds of S-nZVI particles were prepared through different methods including the chemical reduction method (CH-S-nZVI) and the bioprecipitation method (BP-S-nZVI), and then their performances in TCE remediation in seawater environment were thoroughly compared. The results suggested that the TCE removal by CH-S-nZVI particles in seawater is reduced compared to that in fresh water. However, the difference is negligible for BP-S-nZVI particles. It indicates that the seawater has a relatively strong inhibitory effect on the TCE degradation by CH-S-nZVI, but the inhibition for BP-S-nZVI is very weak. Furthermore, this work verified that sodium chloride and organic matters have obvious inhibitory effects on the TCE dichlorination, while coexisting ions such as NO3-, SO42- and Mg2+ are helpful to the degradation of TCE. The research proved that the performance of BP-S-nZVI particles in seawater is superior to CH-S-nZVI particles, providing a suitable candidate for the treatment of polluted aquifers in coastal and near-shore areas.