The combination of heterogeneous photocatalysis with chemical and physical operations: a tool for improving the photoprocess performance.

V. AUGUGLIARO; M. LITTER; L. PALMISANO; J. SORIA

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2006 vol. 7 p. 127 - 144

1389-5567

Heterogeneous photocatalysis is a process of great potential for pollutant abatement and waste treatment. In order to improve the overallperformance of the photoprocess, heterogeneous photocatalysis is being combined with physical or chemical operations, which affect the chemicalkinetics and/or the overall efficiency. This review addresses the various possibilities to couple heterogeneous photocatalysis with other technologiesto photodegrade organic and inorganic pollutants dissolved in actual or synthetic aqueous effluents. These combinations increase the photoprocessefficiency by decreasing the reaction time in respect to the separated operations or they decrease the cost in respect of heterogeneous photocatalysisalone, generally in terms of light energy. Depending on the operation coupled with heterogeneous photocatalysis, two categories of combinationsexist. When the coupling is with ultrasonic irradiation, photo-Fenton reaction, ozonation, or electrochemical treatment, the combination affects thephotocatalytic mechanisms thus improving the efficiency of the photocatalytic process. When the coupling is with biological treatment, membranereactor, membrane photoreactor, or physical adsorption, the combination does not affect the photocatalytic mechanisms but it improves the efficiencyof the overall process. The choice of the coupling is related to the type ofwastewater to be treated.Asynergistic effect, giving rise to an improvementof the efficiency of the photocatalytic process, has been reported in the literature for many cases.