Modified acid treated bentonites as catalysts in selective catalytic reduction of nitrogen oxides by ammonia (SCR-NH3)

Corinne Trabbia

Modified acid treated bentonites as catalysts in selective catalytic reduction of nitrogen oxides by ammonia (SCR-NH3).

Rel. Stefania Specchia. Politecnico di Torino, Corso di laurea magistrale in Ingegneria Chimica E Dei Processi Sostenibili, 2020

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Abstract

Modified acid treated bentonites have been studied as catalysts for the removal of nitrogen oxides (NOx) from power plants off-gases in the selective catalytic reduction of NOx by ammonia (SCR-NH3). The main steps of this work have been the preparation of samples, characterization of samples (by XRD, FT-IR, UV-vis and TG) and the application of obtained catalysts in SCR-NH3. Clays and clay minerals are recognized as the materials of the 21st century for being abundant, inexpensive and environmentally friendly; therefore, they appear to be good candidates for their application in SCR to overcome the limits of commercial catalysts. Modified bentonites have been here investigated: acid treatment and pillaring resulted to be the best methods of modification of these clays.

The first step for the preparation of an acid-saturated clay is its pre-saturation with Na+; for this reason, pure bentonite is treated with a solution of NaCl