Role of Ni/Fe nanoparticle composition on the degradation of trichloroethylene from water

Different compositions of bimetallic Ni/Fe nanoparticles were synthesized, and its structure and morphology were characterized using Brunauer-Emmett-Teller (BET) surface area, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffractometry (XRD) analyses. Trichloroethylene (TCE) degradation by the nanoparticles was studied and analyzed using a pseudo-first-order reaction rate model. The results showed that the nanoparticles rapidly degrade TCE, with the formation of ethane as the main product. The observed reaction rate constant for the Ni/Fe particles was 2 orders of magnitude higher than the bulk and nano iron. These observations indicated that the nanoparticles with nickel as the second dopant metal is better than the zerovalent iron for TCE degradation. The catalytic effect of nickel was demonstrated by TCE studies of different bimetallic compositions and characterized by the surface-area-normalized reaction rate constant coupled with Ni/Fe scanning transmission electron microscopy-energy-dispersive spectroscopy (STEM-EDS) line profiles. A higher degradation rate was observed with increases in the nickel weight percentage from 2 wt% to 25 wt%. Results from the batch experiments using different metal masses per reaction volume indicated that the surface-area-normalized rate constant was solely dependent on the properties of the bimetallic nanoparticles.