36    REMOVAL OF 2-CHLOROPHENOL
FROM WASTEWATER WITH THE
ULTRASONIC/FENTON PROCESS
Jih-Gaw Lin
Institute of Environmental Engineering
National Chiao Tung University
75 Po-Ai Street
Hsinchu, Taiwan, ROC
Allen C. Chao
Department of Civil Engineering
North Carolina State University
Raleigh, North Carolina
Ying-Shih Ma
Institute of Environmental Engineering
National Chiao Tung University
75 Po-Ai Street
Hsinchu, Taiwan, ROC
ABSTRACT
Using the ultrasonic/Fenton oxidation to remove 2-chlorophenol from wastewater is presented
this 354paper. The combining ultrasonic and Fenton treatment enhances the decomposition efficiency of 2-chlorophennol and reduced the reaction time. In previous studies, the optimal conditions for carrying out the proposed ultrasonic/Fenton process are: pH maintained at 3, ionic
strength of the solution adjusted at 0.1 N, ultrasonic amplitude maintained at 120 mm. and the
reaction temperature controlled at 25°C. In this study, the influent of Fenton reagent concentration and ratios of Fe2+ to H,02 on the removal efficiency of 2-chlororphenol is investigated.
Laboratory results indicate that the percentage of 2-chlorophenol decomposition increases for
higher concentrations of Fenton reagent applied. If the concentration of H20, exceeds 50 mg/L.
more than 100% of 2-chlorophenol is decomposed with more than 80% mineralized. The kinetics
of the 2-chlorophenol decomposition rate can be fitted with a pseudo first-order kinetic equation,
and the reaction rate constants are dependent upon the concentration of Fenton reagent applied.
With increasing Fenton reagent concentrations, the observed reaction rate constants also increase. The oxidation/reduction potential (ORP) of the reaction is also monitored. Variations of
the monitored ORP values are related to the oxidation of 2-chlorophenol.
INTRODUCTION
Chlorinated organic substances that are thought to be carcinogenic have been detected in raw
wastewater and also in the chlorinated drinking water as well as wastewater effluent. They are
formed in natural environments as metabolites of agricultural pesticides and in some industrial
plants. For example, chlorophenols, chlorinated enol lactones and cyclopenten-1. 3diones were
formed during chlorination of softwood kraft pulp. In water or wastewater treatment plants, the
chlorination process is often used for disinfection. Natural water often contains humic materials
(Smeds et al., 1995) which are precursors to the formation of carcinogens. The applied chlorine
may react with these organic substances to form the various chlorinated by-products (Karlsson et
al., 1995; Smeds et al., 1995). These chlorinated by-products have been reported to be carcino-
52nd Purdue Industrial Waste Conference Proceedings. 1997. Ann Arbor Press. Chelsea. Michigan 48118. Printed in
U.S.A.
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