In situ generation of hydrogen peroxide from pharmaceuticals single ozonation: A comparative study of its application on Fenton like systems

• A mixture of two pharmaceuticals compounds has been completely removed by means of single ozonation.
• Single ozonation of a mixture of pharmaceuticals yields in situ generation of hydrogen peroxide.
• A response surface method was applied to optimize experimental conditions for hydrogen peroxide formation.
• Hydrogen peroxide formed was used for a second process (Fenton like systems) to improve the degree of mineralization.

The oxidation of a mixture of two pharmaceutical compounds (sulfamethoxazole and acetaminophen) was carried out by means of single ozonation as initial process for in situ production of hydrogen peroxide and in a subsequent step this hydrogen peroxide was used for a sequential treatment in combination with Fenton or photo-Fenton systems. From single ozonation, fast and complete elimination of two pharmaceuticals were achieved but at the end of the ozonation time only a 10% of total organic carbon (TOC) was removed. The addition of ferrous ions (Fenton process) to the reaction media after single ozonation did not improve the extent of mineralization. The application of photo-Fenton process resulted in a markedly increase in the mineralization efficiency, nevertheless total mineralization was not attained. A simple kinetic model of the processes allowed the pseudo-first order kinetic constant calculations. Higher rate constants of the photo-Fenton system were due to photochemical regeneration of ferrous ions.