Tailoring dual redox-acid functionalities in VOx/TiO2/ZSM5 catalyst for simultaneous abatement of PCDD/Fs and NOx from municipal solid waste incineration

A series of VOx/TiO2/ZSM5 were prepared in order to enhance the acid functionalities of commercially used VOx/TiO2 for the combined abatement of NO and o-dichlorobenzene (o-DCB, model molecule to simulate dioxins and furans) from the off-gases of a Municipal Solid Waste (MSW) incinerator plant. The catalysts have been prepared by wet impregnation varying the TiO2 content from 0 to 46%. VOx/TiO2 was also prepared as a reference sample. Combining catalysts characterization (N2 adsorption-desorption isotherms, XRD, TEM, NH3-TPD, H2-TPR and Raman) and activity data, we found that high TiO2 loading VOx/TiO2/ZSM5 catalyst, is highly suitable catalyst for dDiNOx process. The NO conversion is higher than the reference VOx/TiO2 catalyst partly due to higher amount of acid sites provided by the zeolite and partly due to Ti-V interaction, which is a key factor in the conversion of both o-DCB and NO. The TiO2 is heterogeneously dispersed over zeolite, but VOx dispersion is enhanced as the TiO2 content is increased, leading to a higher active polymeric species contribution, as in the sample V/46Ti/Z (confirmed by correlation between TOF and Ti-V interaction).