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), Vol. 98:25; 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
ORGANIC CHLORINE COMPOUNDS
OXIDATION
PHOTOLYSIS
RADIOLYSIS
PHENOLS
CATALYSIS
CHEMICAL REACTION KINETICS
COMPILED DATA
GAMMA RADIATION
HYDROXYL RADICALS
PH VALUE
REACTION INTERMEDIATES
TITANIUM OXIDES
AROMATICS
CHALCOGENIDES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
DATA
DECOMPOSITION
ELECTROMAGNETIC RADIATION
HYDROXY COMPOUNDS
INFORMATION
IONIZING RADIATIONS
KINETICS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
RADIATION EFFECTS
RADIATIONS
RADICALS
REACTION KINETICS
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
400500* - Photochemistry
400600 - Radiation Chemistry
400201 - Chemical & Physicochemical Properties