Advanced chemical oxidation: Its present role and potential future in hazardous waste treatment

Journal Article · Fri Jan 01 00:00:00 EST 1993 · Waste Management; (United States)

DOI:https://doi.org/10.1016/0956-053X(93)90070-D· OSTI ID:5607509

Huang, C P; Dong, Chengdi; Tang, Zhonghung ^[1]

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1. Univ. of Delaware, Newark, DE (United States). Dept. of Civil Engineering

Chemical oxidation reactions involving hydroxyl radicals have been extremely effective in the destruction of organic pollutants. These advanced chemical oxidation processes (AOP) generally use a combination of oxidation agents (such as H[sub 2]O[sub 2] or O[sub 3]), irradiation (such as uv or ultrasound), and catalysts (such as metal ions or photocatalysts) as a means to generate hydroxyl radical. The hydroxyl radical is one of the strongest inorganic oxidants next to elemental fluorine. The hydroxyl radical is stable over a wide pH range, up to pH 10. The hydroxyl radical reacts with organic by three major mechanisms: hydroxy addition, hydrogen abstraction, and electron transfer. Several AOP systems are reviewed first. The merits as well as limitations of these systems are discussed. The potential of AOP for future hazardous wastes treatment is then demonstrated by four AOP systems, H[sub 2]O[sub 2]/Fe[sup 2+], TiO[sub 2]/uv/O[sub 2], H[sub 2]O[sub 2]/uv/O[sub 2], and TiO[sub 2]/uv/H[sub 2]O[sub 2], exemplified by chlorophenols. A reaction scheme can be generalized for the oxidation of halogenated phenols by advanced chemical oxidation, specifically, ones involving hydroxyl radicals. Upon the attack of a halogenated phenol, ArX[sub n]OH, by a hydroxyl radical, OH[center dot] a free radical, Ar(OH)[sub 2]X[sub n], is formed. This free radical can undergo two reaction paths: (1)hydroxylation without dechlorination (Type A) and (2) hydroxylation with dechlorination (Type B). It has been observed that mono-halogenated phenols (n=1) only follow Type A path; dichlorophenols (n=2) and trichlorophenols (n=3) can have both Type A and Type B reaction pathways; tetrahalogenated (n=4) and pentahalogenated (n=5) phenols only follow Type B reaction pathway..

• OSTI ID: 5607509
• Journal Information: Waste Management; (United States), Vol. 13:5-7; ISSN 0956-053X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CHLORINATED AROMATIC HYDROCARBONS
OXIDATION
HAZARDOUS MATERIALS
WASTE PROCESSING
WASTE WATER
DECONTAMINATION
AROMATICS
CHEMICAL REACTIONS
CLEANING
HALOGENATED AROMATIC HYDROCARBONS
HYDROGEN COMPOUNDS
LIQUID WASTES
MANAGEMENT
MATERIALS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXYGEN COMPOUNDS
PROCESSING
WASTE MANAGEMENT
WASTES
WATER
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)
540220 - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)
400201 - Chemical & Physicochemical Properties