Sensitized Photo-Degradation of Chlorophenols in a Continuous Flow Reactor System

Abstract

A dye-sensitized photo-oxidation process has been developed in a continuous flow reactor system. Chlorophenols from mono- to penta- in synthetic solutions were successfully degraded in the presence of visible light radiation, methylene blue and air aeration. Investigation on some relations between reduction ratio of chlorophenol and dose number, air flow rate, and volumetric rate of light absorption shows that dose number as the combination of light intensity and retention time is a critical factor for optimum design. The amount of the air demand per unit of reduced chlorophenol is estimated as about 50 - 80 L.g−1. The residue of methylene blue in wastewater can be removed by passing through an adsorption column filled by natural zeolite (clinoptilolite). Some real wastewaters from coke plant, paper mill and machinery factory were treated in the system. After 1 hour treatment, chlorophenol can be degraded from 90 to 99% and COD was reduced from 30 to 60% depending on the composition and characteristics of the wastewaters.