Process Safety and Environmental Protection, Vol.127, 36-44, 2019
Reductive and adsorptive elimination of bromate from water using Ru/C, Pt/C and Pd/C in the absence of H-2: A comparative study
Three typical catalysts of hydrogenation, Ru/C, Pt/C and Pd/C, are compared for the first time to eliminate bromate in water. As Ru/C, Pt/C and Pd/C are comprised of 5 wt% of metals and porous activated carbon, they exhibit similar morphologies and textural properties, as well as surface charges in water. Nevertheless, Ru/C seems more catalytic active than Pt/C and Pd/C based on temperature-programmed reduction analyses. When Ru/C, Pt/C and Pd/C are used to eliminate bromate in water, Ru/C successfully eliminates a large fraction of bromate ions present in water via its conversion to bromide and partial adsorption. Nevertheless, Pt/C and Pd/C are barely capable of eliminating bromate and converting it to bromide even at elevated temperatures. Regardless of catalyst species, the acidic conditions appears to be more favorable for bromate elimination, but alkaline conditions inhibit bromate elimination by the three catalysts. The presence of other existing anions certainly interferes with bromate elimination, especially, by Ru/C possibly due to the fact that the other existing anions were adsorbed onto the surface of catalyst. In addition, Ru/C, Pt/C and Pd/C are all reusable for bromate reduction: particularly used Ru/C could maintain > 70% of its original capacity for eliminating bromate. These comparisons reveal that Ru/C is certainly a more advantageous catalyst for eliminating bromate via reduction to bromate and adsorption. The findings of this study are valuable and important for developing control technologies of bromate in water. (C) 2019 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.