The principle of the water treatment by heterogeneous photocatalysis uses the excitation by the ultraviolet light of a
semiconductor in the form of solid particles settings in contact with water to be treated [5]. The heterogeneous
photocatalysis is started by the semiconductor material irradiation with photons of energy adapted to the solid. It
allows fast oxidation until the complete mineralization of many organic compounds, nitrogenized, etc. adsorbed on
catalyst. It is necessary indeed that there is mass transfer of the pollutant of the liquid phase towards the surface of
catalyst so that there can be reaction and adsorption is the first stage necessary to any heterogeneous catalytic
reaction.