Evaluation of Photocatalytic Materials for Water Purification: Overview of the New CEN Standard Test

TiO2 photocatalysis offers an attractive alternative to conventional water treatment technologies leading directly to the degradation of organic pollutants, compared to transferring them from one phase to another as in the case of membranes or activated carbon. There is an increasing interest on using photocatalysis for water treatment, rendering reliable evaluation of performance of the catalytic materials necessary. Methods for testing photocatalysts used in water treatment are generally not harmonized. Two ISO standards are available for assessing the photocatalytic activity of surfaces with regards to water purification, which are based on the photo-bleaching of methylene blue and the oxidation of DMSO, respectively. A new European standard for assessing the photocatalytic activity of materials has been developed and is under publication by the European Committee for Standardization, CEN TC386/WG3. Evaluation of the performance of photocatalytic materials in water purification is based on measurement of phenol degradation with UV irradiation under controlled conditions. The proposed standard method is applicable to materials in the form of powders (suspensions in water, slurries). İn this study, the new CEN standard test will be presented, while its differentiation from the existing ones, its applicability and the process followed for its validation, will be discussed.