US EPA

5882769 

Journal Article 

Kinetics and reaction pathway of Aroclor 1254 removal by novel bimetallic catalysts supported on activated carbon 

Xu, J; Liu, Y; Tao, F; Sun, Y 

2019 

1 

Science of the Total Environment
ISSN: 0048-9697
EISSN: 1879-1026 

ELSEVIER SCIENCE BV 

AMSTERDAM 

651 

Pt 1 

749-755 

English 

30245430 

10.1016/j.scitotenv.2018.09.200 

WOS:000447915400073 

Bimetallic catalysts supported on activated carbon (AC) with high metal loadings were prepared by an ion-exchange method. AC-supported Ni-Cu, Ni-Zn and Ni-Pd bimetallic catalysts were used to decompose Aroclor 1254, which is one of the most commonly used commercial mix of polychlorinated biphenyls. Characterization by scanning electron microscopy and energy-dispersive X-ray analysis showed that the metals were uniformly distributed on the surfaces and inside the catalysts. The efficiencies of Aroclor 1254 decomposition were measured at different reaction temperatures and times. With increasing temperature, the catalytic activities increased and the activation energies of the reactions decreased, resulting in higher decomposition efficiencies. At 300 °C in a nitrogen atmosphere, Aroclor 1254 decomposition efficiencies of 99.3%, 99.4% and 99.5% were achieved for reactions with Ni-Cu/C, Ni-Zn/C and Ni-Pd/C, respectively. The kinetics and pathway of the decomposition reaction were discussed, and we concluded that the reactivity of the chlorine atoms located on the benzene rings followed the order para-position > meta-position > ortho-position. The PCBs were dechlorinated stepwise to form the final biphenyl product. The design concept and synthetic strategy developed in this study are of great significance in the disposal of chlorinated organic compounds, for use with the existing adsorption technology of AC.