Dechlorination of trichloroethylene in solution over supported nano zero valent Fe and Cu/Fe bimetal on exfoliated graphite

Degradation of organic halides by reductive dehalogenation promoted by zerovalent metals is a very active research area. The use of nano-sized particles of zero valent iron （ZVI） or bimetallic combinations of ZVI currently attracts the most attention due to their high surface areas and high reactive activity. The introduction of second catalytic metals, such as Pd, Pt, Cu, or Ni, results in an even higher dehalogenation rate. The supported zero-valent iron materials have higher activity and greater flexibility for environmental remediation applications than other forms of ZVI. Nano ZVI supported on micro-scale exfoliated graphite was prepared by using KBH4 as the reducing agent in the H2O/ethanol solution of Fe^2＋ in the laboratory. Then the ethanol solution of Cu^2＋ was added to the fleshly prepared wet supported nano ZVI. The Fe/Cu bimetallic particles supported on the graphite were obtained because of the reduction and deposition of Cu on the Fe surface. The TEM image showed that iron particles were highly dispersed on the surface of graphite. In this study, supported zero valent Cu/Fe bimetallic nanoparticles were used for the dehalogenation of trichloroethylene （TCE） in batch experiments. The dechlorination rate of supported zero valent Fe/Cu bimetallic nanoparticles was greater than the supported nano ZVI. Supported Cu/Fe bimetal with 4 wt% Cu had the fastest dehalogenation rate than that with different content of Cu. When the nana FeO dosage was 5 g/L in the dehalogention system, 8 mg/L of TCE was completely dechlorinated within 4 hours. Increasing or decreasing the FeO dosage, the dechlorination rate could be worse. When the concentration of Fe^2＋ was 0.05 mol/L during the preparation by KBH4 reduction, the nano Cu/Fe particles exhibited the spheral shape with 50-80 nm in size. When the concentration of Fe^2＋ was higher （0.2 mol/L）, the nano particles were the palpus structure and had the poor dehalogenation effect on the TCE.

Dechlorination of trichloroethylene in solution over supported nano zero valent Fe and Cu/Fe bimetal on exfoliated graphite