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Preparation of Polyoxometalate-based Photo-responsive Membranes for the Photo-activation of Manganese Oxide Catalysts
Published on: August 7, 2018
Oxidation kinetics of pentachlorophenol by manganese dioxide
Ling Zhao1, Zhiqiang Yu, Pingán Peng
1State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Wushan, Guangdong 510640, People's Republic of China.
Environmental Toxicology and Chemistry
|November 9, 2006
Summary
Manganese dioxide (MnO2) transforms pentachlorophenol (PCP) via abiotic reactions. Reaction rates depend on PCP, MnO2, and H+ concentrations, with background electrolytes inhibiting the process.
Area of Science:
- Environmental Chemistry
- Chemical Kinetics
- Water Treatment
Background:
- Pentachlorophenol (PCP) is a persistent organic pollutant.
- Manganese dioxide (MnO2) is a potential oxidant for pollutant degradation.
Purpose of the Study:
- To investigate the abiotic transformation kinetics of PCP by MnO2.
- To understand the influence of solution chemistry and reactant concentrations on PCP degradation.
Main Methods:
- Kinetic studies of PCP transformation by MnO2.
- Analysis of reaction products using gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS).
Main Results:
- PCP transformation rates showed positive orders with respect to [PCP] (1.07), [MnO2] (0.91), and [H+] (0.87).
- Dissolved Mn2+ and Ca2+ inhibited the reaction by blocking MnO2 active sites.
- Major products identified were isomeric nonachlorohydroxybiphenylethers; minor products included tetrachlorohydroquinone and tetrachlorocatechol.
Conclusions:
- The reaction proceeds through parallel pathways, forming either dimers or hydroquinone/catechol derivatives.
- The transformation involves both dehydrochlorination and hydroxylation steps.
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