Decontamination and disinfection of water by solar photocatalysis: The pilot plants of the Plataforma Solar de Almeria

This work reviews the use of sunlight to produce the HO
- radicals by TiO2 nanophotocatalysis. The reacting systems necessary for performing solar photocatalysis will be described and the factors which govern the kinetics of photocatalysis such as initial concentration of reactant, mass of catalyst, pH, temperature, radiant flux and concentration of oxygen are highlighted. Several approaches in order to improve the photocatalysis efficiency of TiO2 will be also described. Solar reactors engineering issues for photocatalytic water treatment will be reviewed as well as the use of the solar photocatalytic processes to inactivate microorganisms present in water, placing special emphasis to the mechanisms acting during the process, mainly hydroxyl radical and singlet oxygen generation, and on experimental systems made to optimize this disinfection technique. Heterogeneous photocatalysis is also an attractive technique for obtaining hydrogen in a clean way. In the last decades different photocatalytic systems for hydrogen generation with simultaneous removal of organic pollutants have been studied at laboratory scale but, so far, little has been published about these systems at a larger scale. The present work will also show the simultaneous photocatalytic hydrogen production and organic pollutant removal under direct solar irradiation and at pilot-plant scale at the Plataforma Solar de Almería (PSA).