Performance of metal-free carbonaceous catalysts in the removal of paracetamol by catalytic wet peroxide oxidation

Abstract

The performance of metal-free carbonaceous catalysts was evaluated in the removal of paracetamol, chosen as model pharmaceutical micropollutant, by catalytic wet peroxide oxidation (CWPO). The carbon materials were prepared from pentaerythritol tetraacrylate and divinylbenzene copolymer with bis(2-ethylhexyl) phthalate as porogen followed by subsequent carbonization at 900 ºC under N2 atmosphere. The synthesized material was grinded to powder and separated into different samples, according to its granulometry. The sample with particle sizes between 53 and 106 µm (catalyst Mon11) was further functionalized with nitric acid 5 M at 120 °C for 3 h (catalyst Mon11F) to increase the hydrophilicity of the original material. Both catalysts revealed high activity in CWPO, completely removing the pharmaceutical compound within 6 and 24 h of reaction at 80 ºC, when Mon11 and Mon11F were used, respectively. Total organic carbon (TOC) conversion achieved values of 86.8 and 75.8% with Mon11 and Mon11F, respectively. Adsorption tests at the same operating conditions resulted in removals of paracetamol after 24 h around 29% for Mon11 and 11% for Mon11F, confirming the predominance of catalytic removal of the pollutant in the CWPO runs.