Efficiency of a Magnetic Multi-Core Shell Catalyst in the Degradation of Paracetamol and Sulfamethoxazole: A Catalytic Wet Peroxide Oxidation Approach

With the populational rise in the last decades, the potable water available has been a common concern. In this scenario, pharmaceuticals, mostly excreted in sewers, are not treated by conventional wastewater treatment plants. This study explores the synthesis of a magnetic multi-core shell catalyst and its efficiency in the degradation of paracetamol (PCM) and sulfamethoxazole (SMX) by catalytic wet peroxide oxidation (CWPO). The catalysts were synthesized in a two-step process. The core was initially synthesized via a coprecipitation methodology, followed by the sol-gel synthesis of the niobium pentoxide shell. The tests were conducted with three different matrixes, two in single components ([SMX] =10 ppm or [PCM] =100 ppm) and one in multi-component ([SMX] = 10 ppm and [PCM] = 100 ppm). The liquid-phase oxidation reactions were carried out at 80 °C, pH 3.5, and stirring at 300 rpm and a catalysts concentration of 2.5 g L^-1. Results showed that the catalyst maintained its magnetic property, accelerating the removal process from the matrix and resisting the CWPO process, not showing leaching. The degradation of PCM and SMX in the single-component matrixes allowed removing about 90.9% of PCM and 22.8% of SMX in 4h. Still, the multi-component removed 88.7% of PCM and 80.1% of SMX in 4h, suggesting some synergy between the catalyst and the pharmaceuticals. In conclusion, the degradation of the pharmaceuticals by the new catalyst developed proved to have a high degradation rate and low toxicity.