title: Degradation and dechlorination of pentachlorophenol by microwave-activated persulfate.
abstract: The degradation performance of pentachlorophenol (PCP) by the microwave-activated persulfate (MW/PS) process was investigated in this study. The results indicated that degradation efficiency of PCP in the MW/PS process followed pseudo-first-order kinetics, and compared with conventional heating, microwave heating has a special effect of increasing the reaction rate and reducing the process time. A higher persulfate concentration and reaction temperature accelerated the PCP degradation rate. Meanwhile, increasing the pH value and ionic strength of the phosphate buffer slowed down the degradation rate. The addition of ethanol and tert-butyl alcohol as hydroxyl radical and sulfate radical scavengers proved that the sulfate radicals were the dominant active species in the MW/PS process. Gas chromatography-mass spectrometry (GC-MS) was employed to identify the intermediate products, and then a plausible degradation pathway involving dechlorination, hydrolysis, and mineralization was proposed. The acute toxicity of PCP, as tested with Photobacterium phosphoreum, Vibrio fischeri, and Vibrio qinghaiensis, was negated quickly during the MW/PS process, which was in agreement with the nearly complete mineralization of PCP. These results showed that the MW/PS process could achieve a high mineralization level in a short time, which provided an efficient way for PCP elimination from wastewater.
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China.
authors.forename: Chengdu
authors.initials: C
authors.lastname: Qi
authors.forename: Xitao
authors.initials: X
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.forename: Chunye
authors.initials: C
authors.lastname: Lin
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
authors.forename: Wenxiao
authors.initials: W
authors.lastname: Shi
authors.forename: Qu
authors.initials: Q
authors.lastname: Sun
authors.forename: Hao
authors.initials: H
authors.lastname: Xiao
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry; D054879:Halogenation; D017665:Hydroxyl Radical; D007700:Kinetics; D008872:Microwaves; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D010416:Pentachlorophenol / Q000737:chemistry* / Q000633:toxicity; D010776:Photobacterium / Q000187:drug effects; D013431:Sulfates / Q000737:chemistry*; D014733:Vibrio / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000633:toxicity
chemical_list: D013431:Sulfates; D014874:Water Pollutants, Chemical; C069025:sulfate radical; D017665:Hydroxyl Radical; D010416:Pentachlorophenol