Radiolytic and TiO[sub 2]-assisted photocatalytic degradation of 4-chlorophenol. A comparative study

Journal Article · Thu Jun 23 00:00:00 EDT 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100076a019· OSTI ID:6980504

Stafford, U; Gray, K A; Kamat, P V ^[1]

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1. Univ. of Notre Dame, IN (United States)

Mechanistic and kinetics details of 4-chlorophenol (4-CP) oxidation have been elucidated by radiolytic and photocatalytic techniques. When 4-chlorophenol is oxidized by [gamma]-radiolysis in conditions favoring hydroxyl radical oxidation ([sup [sm bullet]]OH), significant concentrations of 4-chlorocatechol (4-CC) and hydroquinone (HQ) are formed as intermediates. Phenol is the only major intermediate when conditions favoring reduction by hydrated electrons are employed. 4-CC and HQ are not detected when 4-chlorophenol is oxidized with azide radicals. Hydroxyl radical mediated oxidative degradation rates of 4-CP are similar at pH 3.0 and pH 6.1. The 4-CP degradation rate is relative slower at pH 9.1, and no aromatic intermediates are detected. These results confirm the proposal that hydroxy-mediated 4-CP oxidation follows at least three separate degradation pathways, forming 4-CC, HQ, and unidentified, mostly nonaromatic compounds, as reaction intermediates enroute to complete mineralization. Pulse radiolysis experiments have also been carried out to characterize the radical transient species formed during the oxidation of 4-CP (pH 6 and 10) and 4-chlorocatechol (pH 6). 41 refs., 6 figs., 3 tabs.

• OSTI ID: 6980504
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 98:25; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400201 -- Chemical & Physicochemical Properties
400500* -- Photochemistry
400600 -- Radiation Chemistry
AROMATICS
CATALYSIS
CHALCOGENIDES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPILED DATA
DATA
DECOMPOSITION
ELECTROMAGNETIC RADIATION
GAMMA RADIATION
HYDROXY COMPOUNDS
HYDROXYL RADICALS
INFORMATION
IONIZING RADIATIONS
KINETICS
NUMERICAL DATA
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PH VALUE
PHENOLS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
RADIATION EFFECTS
RADIATIONS
RADICALS
RADIOLYSIS
REACTION INTERMEDIATES
REACTION KINETICS
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS