5. Emerging technologies

Some treatments that are currently in the research/development phase, or have a few industrial units in operation, may eventually be of particular interest. These include

• High-temperature dust filtration, which has many applications but is difficult to develop technologically;

• the development of new catalysts for the removal of NO _x from combustion flue gases;

• photocatalysis: in this case, the pollutant is oxidized on a catalyst in the presence of UV radiation. Catalysts are made of metal oxides such as titanium oxide supported on inert materials (alumino-silicate, paper, glass, etc.). This process needs to be validated in terms of by-product generation. Work is being carried out to find new materials (nitrogenous in particular)...