Effect of hydroxypropyl-beta-cyclodextrin on the degradation of pentachlorophenol by potassium monopersulfate catalyzed with iron(III)-porphyrin complex.
A novel biomimetic catalytic system containing a supramolecular complex between iron(III)-tetrakis(p-sulfonatophenyl)porphyrin [Fe(III)-TPPS] and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was examined for the potassium monopersulfate catalyzed oxidation of pentachlorophenol (PCP). In the absence of HP-beta-CD, the percentage of PCP disappearance and the numbers of chlorine atoms released from PCP increased to 50% and 1.5 for a 1-day reaction period, respectively. However, in the presence of HP-beta-CD, the PCP completely disappeared and the number of chlorine atoms from PCP was increased to 3.1. o-Tetrachloroquinone, 2- and 4-hydroxyl-nonachlorodiphenyl ethers, and octachlorodibenzo-p-dioxin were detected among the oxidation products. In the absence of HP-beta-CD, the percentage of PCP conversion to oxidation products increased and then reached plateau. In the presence of HP-beta-CD, the amount of oxidation products produced initially increased for the first 10 min and thereafter decreased gradually. These results suggest that the addition of HP-beta-CD results in the further degradation of oxidation products. In addition, the mineralization of PCP to CO2 was investigated using 14C6-labeled PCP. After a 1-day reaction period, 24% of the 14C6-labeled PCP was converted to 14CO2 in the presence of HP-beta-CD, although significant 14CO2 generation was not observed in its absence. The effect of HP-beta-CD on the facilitation of PCP degradation can be attributed to the fact that the self-oxidation of Fe(III)-TPPS is prevented by the formation of a stable supramolecular complex between HP-beta-CD and Fe(III)-TPPS.
Fukushima
Masami
M
National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan. m-fukushima@aist.go.jp
Tatsumi
Kenji
K
D000073738:2-Hydroxypropyl-beta-cyclodextrin; D002245:Carbon Dioxide / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry*; D010416:Pentachlorophenol / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D017680:Potassium Compounds / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013431:Sulfates / Q000737:chemistry*; D047392:beta-Cyclodextrins / Q000737:chemistry*
D005290:Ferric Compounds; D011166:Porphyrins; D017680:Potassium Compounds; D013431:Sulfates; D047392:beta-Cyclodextrins; D002245:Carbon Dioxide; D000073738:2-Hydroxypropyl-beta-cyclodextrin; C009007:potassium persulfate; D010416:Pentachlorophenol