Process conditions for the mineralization of a biorefractory polycyclic aromatic hydrocarbon in soils using catalyzed hydrogen peroxide

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:416896

Stanton, P C; Watts, R J ^[1]

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1. Washington State Univ., Pullman, WA (United States)

Catalyzed hydrogen peroxide (H{sub 2}O{sub 2} and soluble iron or mineral catalysts) was investigated as a basis for mineralizing benzo[a]pyrene (BaP), a hydrophobic and toxic polycyclic aromatic hydrocarbon, in two soils of varied complexity. The process is based on Fenton`s reagent, which can be implemented in soils to generate hydroxyl radicals. This short-lived species reacts with most organic contaminants at near diffusion-controlled rates, providing a mechanism for potential rapid soil remediation. Benzo[a]pyrene labeled with {sup 14}C was added to silica sand and a silt loam loess soil; mineralization processes were then optimized using central composite rotatable experimental designs. Variables investigated during the optimization included H{sub 2}O{sub 2} concentration, slurry volume, iron (II) amendment, and pH. Experimental data were evaluated by linear regression to develop empirical relationships and interactions between the variables. The equations were then used to develop three-dimensional response surfaces to describe BaP mineralization. The results from the response surfaces showed that 74% and 78% BaP mineralization was achieved in the silica sand and loess soils, respectively. The balance of the contaminant carbon remained with the soil fraction and was probably irreversibly sorbed. Desorption measurements over 5 d confirmed negligible desorption; however, oxidation reactions, which were complete within 24 h, documented >78% BaP mineralization, suggesting that the contaminant was oxidized, at least in part, in the sorbed phase. The results show that catalyzed H{sub 2}O{sub 2} has the ability to rapidly mineralize BaP that is not irreversibly sorbed.

• OSTI ID: 416896
• Report Number(s): CONF-951023--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
BENZOPYRENE
CARBON 14
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL REACTIONS
DESORPTION
DIFFUSION
HYDROGEN PEROXIDE
HYDROXYL RADICALS
IRON
LOAM
MINERALIZATION
OXIDATION
PH VALUE
POLLUTANTS
POLYCYCLIC AROMATIC HYDROCARBONS
SAND
SOILS
TRACER TECHNIQUES