A review of catalytic processes for the destruction of PCDD and PCDF from waste gases

The current literature concerning the catalytic destruction of dioxins and of related model compounds is reviewed. Several different catalyst formulations have been tested, but V-rich vanadia-tungsta-titania catalysts seem to be mostly applied and allow reducing the dioxins concentration well below the limits of 0.1 ng TEQ/Nm3, as required by the EU directives. Other catalysts (in particular the noble metal-based ones) seem to be less efficient, due to deactivation effects and/or a considerable amount of polychlorinated by-products formation during oxidation activity. The coupled de-NOx and dioxin destruction systems compete with activated carbon adsorption for efficiency in PCDD/F removal from gases.