Ceria dispersed on carbon materials for the catalytic ozonation of sulfamethoxazole

Two catalysts containing ceria dispersed on the surface of multi-walled carbon nanotubes and activated carbon were prepared and characterized by several techniques. They were investigated as ozonation catalysts for the mineralization of the antibiotic sulfamethoxazole (SMX). Both materials enhanced the mineralization of SMX relatively to single ozonation. A strong synergetic effect between carbon materials and ceria was observed, leading to higher mineralization degrees. In the catalytic ozonation with these materials both surface and bulk reactions occur. The efficiency of catalysts was mainly affected by the amount of Ce3+ species on the surface. The presence of carbon materials containing ceria led to a faster degradation of pyruvic and maleic acids. The original sulfur of SMX was almost completely converted to sulfate and part of nitrogen was converted to NH4+ and NO3−. Microtox tests revealed that simultaneous use of ozone and the prepared catalysts originated lower acute toxicity.

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