Comparative study of trichloroethylene removal by different carbons and FeNi-carbon composites

Nanoscale zero-valent iron (NZVI) has been proven effective at degrading environmental ‎contaminants of concern, yet field performance as an in situ remedy is lacking due to short ‎reactive lifetimes and poor transport through porous media. The main ‎objective of this study was to investigate and compare the performance of different carbon ‎powders with different properties (surface ‎area, pore-volume, conductivity, functional groups) on trichloroethylene (TCE) removal and transport ‎properties. Carbon ‎powders were used as the support for bimetallic FeNi nanoparticles, the composites were stabilized by poly(vinyl pyrrolidone), and the performance of ‎the modified novel FeNi-carbon composites was compared. It was confirmed that several properties of the carbon were found to not affect TCE degradation by the FeNi-C composites while ‎surface area, pore size, and functional groups are responsible for TCE adsorption by carbon ‎powders. Carbon particle size was found to inversely affect the transport of the composite ‎through porous media, with smaller carbon supports such as carbon black correlating to a wider ‎radius of influence, as compared to larger biochar carbon particulates. Significantly, FeNi-C ‎shows improved TCE degradation over Fe or FeNi nanoparticles alone, indicating the utility of ‎using carbon supports to promote dehalogenation reactions and increase NZVI longevity‎.