Enhanced degradation of trichloroethylene in nano-scale zero-valent iron Fenton system with Cu(II)

Degradation of trichloroethylene (TCE) in nano-scale zero-valent iron (nZVI) Fenton system with Cu(II) was investigated in a closed batch system. TCE was significantly degraded (95%) in 10 min in nZVI Fenton system with 20mM Cu(II) at initial pH 3, while slight degradation (25%) was observed in nZVI Fenton system without Cu(II) at the same experimental condition. Aqueous Fe(II) concentration proportionally increased (1.2-19.6mM) with increasing Cu(II) concentration (1-20mM). Surface analyses using X-ray spectroscopy showed that metallic Cu was formed on the nZVI surface and surface Fe(0) decreased by 1.4 times after the addition of Cu(II) to nZVI suspension. Kinetic rate constant for TCE degradation at 15.3mM nZVI (4.1989 min(-1)) increased by 1.8 times till the increase of nZVI concentration by 5 times and then showed a saturation pattern at higher nZVI concentration. As Cu(II) concentrations increased in the Cu/nZVI Fenton system, the rate constant increased linearly (R(2)=0.979). No significant difference has been observed in the degradation kinetics of TCE by Cu/nZVI Fenton at pH 3 and pH 6 (4.8720 min(-1) vs. 4.9858 min(-1)), whereas the kinetics by nZVI Fenton at pH 6 were 1.6 times faster (0.0318 min(-1)) than at pH 3 (0.0194 min(-1)).