Effects of humic substances on the pattern of oxidation products of pentachlorophenol induced by a biomimetic catalytic system using tetra(p-sulfophenyl)porphineiron(III) and KHSO5.
In the presence of humic substances (HSs), the oxidative conversion of pentachlorophenol (PCP) was found to be efficiently catalyzed by tetra(p-sulfophenyl)porphineiron(III) (Fe(III)-TPPS) using KHSO5 as an oxygen donor. Ortho-tetrachloroquinone (o-TeCQ), 2-hydroxyl-nonachlorodiphenyl ether (2H-NCDE), 4-hydroxyl-nonachlorodiphenyl ether (4H-NCDE), and octachlorodibenzo-p-dioxin (OCDD) were identified as the major byproducts of the reaction. Decreased amounts of these byproducts were produced in the presence of HS. In particular, the addition of HSs with a lower degree of humification resulted in a large decrease in the formation of dimers, such as 2H-NCDE, 4H-NCDE, and OCDD. More than 60% of the chlorine, which was released from PCP, was found in the HS fractions after the reaction. This suggests that chlorinated intermediates from PCP were incorporated into the HS. Pyrolysis-GC/MS and 13C NMR studies confirmed that the binding of the chlorinated intermediates was covalent in nature and that the intermediates were copolymerized with HS via oxidative coupling reactions. A Microtox test demonstrated that the toxicity of the HS fraction containing PCP-derived intermediates was much lower than that of the mixture of PCP and HS in the absence of a catalytic reaction.
Fukushima
Masami
M
National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba-West, Tsukuba 305-8569, Japan. m-fukushima@aist.go.jp
Ichikawa
Hiroyasu
H
Kawasaki
Mikio
M
Sawada
Akira
A
Morimoto
Kengo
K
Tatsumi
Kenji
K
D002384:Catalysis; D004785:Environmental Pollutants / Q000032:analysis* / Q000633:toxicity; D008401:Gas Chromatography-Mass Spectrometry; D006812:Humic Substances / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D010416:Pentachlorophenol / Q000032:analysis / Q000737:chemistry* / Q000633:toxicity; D011166:Porphyrins / Q000737:chemistry*; D018675:Toxicity Tests; D014733:Vibrio; D018508:Water Purification / Q000379:methods*
D004785:Environmental Pollutants; D006812:Humic Substances; D011166:Porphyrins; C016136:tetraphenylporphine sulfonate; D010416:Pentachlorophenol