Catalytic dechlorination of 2,4-dichlorophenol by Pd/Fe bimetallic nanoparticles in the presence of humic acid.
Pd/Fe bimetallic nanoparticles were synthesized for treatment of 2,4-dichlorophenol (2,4-DCP) in the presence of humic acid (HA), in order to understand their applicability for in situ remediation of groundwater. In this case, 2,4-DCP was catalytically dechlorinated to form the final products--phenol (P) via two intermediates, namely o-chlorophenol (o-CP) and p-chlorophenol (p-CP). We demonstrated that the carbon mass balances during the dechlorination were in the range of 82-91%, and other carbons were absorbed on the surface of Pd/Fe bimetallic nanoparticles. Our results suggest the dechlorination reaction of 2,4-DCP by Pd/Fe bimetallic nanoparticles in the presence of HA followed pseudo-first-order kinetics. HA competed for reaction sites on the Pd/Fe bimetallic nanoparticles with 2,4-DCP, and thus reduced the efficiency and rate of the dechlorination of 2,4-DCP. Efficiencies of dechlorination and phenol formations increased significantly as the Pd content increased from 0.10 wt.%, 0.15 wt.% to 0.20 wt.%, the removal percentage of 2,4-DCP increased from 70.4%, 98.4% to 99.4% within 300 min, respectively, the nitrate (NO(3)(-)) content in water also has a significant impact on 2,4-DCP dechlorination efficiency. Our results show that no other intermediates were generated besides Cl(-), o-CP, p-CP and phenol during the catalytic dechlorination of 2,4-DCP.
Zhang
Zhen
Z
Department of Environmental Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China.
Shen
Qiaohui
Q
Cissoko
Naman
N
Wo
Jingjing
J
Xu
Xinhua
X
D002384:Catalysis; D002713:Chlorine / Q000737:chemistry*; D002733:Chlorophenols / Q000737:chemistry*; D006812:Humic Substances; D007501:Iron / Q000737:chemistry*; D053768:Metal Nanoparticles; D046529:Microscopy, Electron, Transmission; D010165:Palladium / Q000737:chemistry*
D002733:Chlorophenols; D006812:Humic Substances; D002713:Chlorine; D010165:Palladium; D007501:Iron; C004762:2,4-dichlorophenol