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Photocatalytic Membrane Reactors in Water Purification

Waste Water Treatment

  1. Raffaele Molinari1,
  2. L. Palmisano2

Published Online: 15 JUL 2005

DOI: 10.1002/047147844X.ww148

Water Encyclopedia

Water Encyclopedia

How to Cite

Molinari, R. and Palmisano, L. 2005. Photocatalytic Membrane Reactors in Water Purification. Water Encyclopedia. 1:791–798.

Author Information

  1. 1

    Università della Calabria, Rende, Italy

  2. 2

    Università di Palermo, Palermo, Italy

Publication History

  1. Published Online: 15 JUL 2005

Abstract

Potable water, industrial water, and wastewater are often polluted by toxic organic species. New methods, such as those involving heterogeneous photocatalytic reactions, allow in many cases a complete degradation of organic pollutants to small and non-noxious species, without using chemicals, avoiding sludge production and its disposal. When combined with membrane separation processes, photocatalytic membrane reactors (PMRs) are obtained. These have some advantages compared to conventional photoreactors. Indeed, confining of the photocatalyst in the reaction environment as a result of the presence of the membrane (separation at molecular level) enables operation with high amounts of catalyst, control of the residence time of the molecules in the reactor, and realization of a continuous process with simultaneous product(s) separation from the reaction environment.

The influence of various operating parameters on the photodegradation rate of various pollutants present in aqueous effluents by means of discontinuous and continuous photocatalytic processes are described. The hybrid continuous photoreactor, where a nanofiltration membrane is used, can give a simplification of clean-up or purification of various types of waters (for industrial, municipal/domestic, and agricultural uses) and no sludge production as well as a saving in chemicals usage. It is expected that these hybrid processes will be considered when plant upgrade is planned and, especially, if sunlight energy can be used for irradiation.

Keywords:

  • photocatalysis;
  • heterogeneous photocatalysis;
  • membrane processes;
  • photocatalytic membrane reactors;
  • wastewater treatments;
  • pollutants photodegradation;
  • membrane photoreactors;
  • water purification;
  • dyes photodegradation;
  • 4-nitrophenol photodegradation;
  • hybrid membrane processes;
  • nanofiltration membrane photoreactors