Bromate reduction in water promoted by metal catalysts prepared over faujasite zeolite

Abstract

Bromate reduction in water has been investigated by using mono and bimetallic catalysts prepared over a faujasite zeolite in a semi-batch reactor under hydrogen at room temperature and atmospheric pressure. The structural synthetic analogue Y of the faujasite zeolite in the sodium form, with different particle sizes (NaY, 700 nm and nanoNaY, 150 nm), was chosen for the preparation of metal catalysts. Ion exchange and incipient wetness impregnation methods were applied to incorporate copper, palladium, rhodium and/or thorium into the faujasite zeolite. Several analytical techniques were used to characterize structural modifications in the metal catalysts and confirm that the metals were successfully trapped in the faujasite structure. The catalytic results demonstrated the importance of the chemical nature of the metals, of the amount of the second incorporated metal, as well as the method used for catalyst preparation. All the metal catalysts showed remarkable performance in the bromate reduction in water, with the bimetallic catalysts presenting the best results, particularly the CuPd pair prepared by the ion exchange method.