Major Challenges in the Design of a Large-Scale Photocatalytic Reactor for Water Treatment

Abstract

Semiconductor photocatalysis is a newly emerging technology for the elimination of harmful chemical compounds from air and water. It couples low-energy ultraviolet light with semiconductors acting as photocatalysts overcoming many of the drawbacks that exist for the traditional water treatment methods. Recent literature has established the potential of this powerful technology to destroy toxic pollutants dissolved or dispersed in water. However, to date no viable pilot plant exists using this technology. In this paper, the challenges that need to be addressed for the scale-up of multiphase photocatalytic reactors are discussed. A new reactor design concept is necessary that must be able to address the two most important parameters, namely, uniform light distribution inside the reactor through the absorbing and scattering liquid to the catalyst, and providing high surface areas for catalyst coating per unit of reactor volume. Two new design configurations for efficient photocatalytic reactors have been discussed that not only address the solution to both of the above problems but also have scale-up potential.