Degradation of Organochlorine Compounds Using Zero Valent Iron (ZVI) Nano Particles Impregnated in Hydrophobic Modified Bentonite

Abstract

The degradation of perchloroethylene (PCE) adsorbed on hydrophobic modified bentonite was investigated. The degradation occurred via reduction of iron particles with zero valence (ZVI) incorporated in hydrophobic surface of bentonite. We compared two different systems, one containing ZVI and another without ZVI. The degradation of PCE was accompanied by decreasing concentrations of PCE and the increase of resulting compounds such as trichloroethylene (TCE), 1,2-dichloroethylene, trans and cis forms, (1,2-cis-DCE and 1,2- trans-DCE). The results show that the PCE is rapidly adsorbed and in contact with ZVI particles is degraded to less toxic compounds, while in the systems without ZVI no significant decrease of PCE was observed, clearly demonstrating that the degradation process occurs through the reduction with ZVI. The rate constant for the system containing ZVI was 0.215 h⁻¹, while for the system without ZVI it was only 0.031 h⁻¹. The results agree with other research, however the reaction was conducted in columns and the clay was zeolite. It can be concluded that the system impregnated with ZVI is extremely interesting as an alternative application for removal of organic compounds containing chlorine due to their persistence and toxic effect on the microorganisms. The system can also be applied as barrier content.