Nanoscale zerovalent iron (nZVI) has been widely used for the dechlorination of chlorinated hydrocarbon in aquatic environments. However, the intrinsic ferromagnetism of ZVI nanoparticles leads to aggregation and result in the loss of reactivity and mobility. Immobilization of NZVI onto low dimensional support, such as 1-dimensional titanate nanotubes (TNTs) or 2-dimensional graphene family has been shown to be good potential support for NZVI. In this presentation, the reactivity of bimetallic Fe/Ni toward trichloroethylene (TCE) dechlorination was evaluated and compared. The TNT-immobilized Fe/Ni was fabricated using nonaqueous thermal decomposition method, while reduced graphene oxide (rGO) supported Fe/Ni nanocomposites were fabricated by in-situ chemical reduction method. Results showed that the TNT@Fe/Ni with particle size of 13±1 nm was well-dispersed on the surface of TNTs. Moreover, a thin-layer of carbon was coated onto the surface of TNT@Fe/Ni, which can not only prevent the aggregation of nZVI but also maintains the reactivity. The pseudo-first order rate constant (k<sub>obs</sub>) of TCE dechlorination by TNT@Fe/Ni was 6.3 h<sup>-1</sup>, which is 3 orders of magnitude higher that pure ZVI. For rGO/Fe/Ni nanocomposites, the 10 – 60 nm Fe/Ni nanoparticles with average particle size of 32 nm are homogeneously dispersed onto the rGO surface. The rGO/Fe/Ni exhibits excellent dechlorination efficiency and rate of TCE and the reaction rate for TCE dechlorination is 2.4 times higher than that of free Fe/Ni. The superior dechlorination activity of Fe/Ni onto low-dimensional support (TNT and rGO) is attributed to the strong interaction between Fe/Ni and support, low internal resistance and rapid diffusion rate of electrons and ions, which can pave a new way to develop the immobilized Fe/Ni nanomaterials for effective and efficient dechlorination of chlorinated hydrocarbons in aqueous solutions.

Immobilization of bimetallic zerovalent iron nanoparticles onto low dimensional supports for enhanced hydrodechlorination of trichloroethylene

256th National Meeting (2018)

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