Synthesis and characterization of SnO2 crystalline nanoparticles: A new approach for enhancing the catalytic ozonation of acetaminophen.

A novel sol-gel method was employed in this study to efficiently synthesize SnO2 nanoparticles to catalyze the ozonation of acetaminophen (ACT) from aqueous solutions. The influence of various parameters including Sn source, type of capping and alkaline agents, and calcination temperature on the catalytic activity of the SnO2 preparations was investigated. The SnO2 nanoparticles prepared by tin tetrachloride as Sn source, NaOH as gelatin agent, CTAB as capping agent and at calcination temperature of 550 °C (SnNaC-550) exhibited the maximum performance in the catalysis of ACT. The optimized catalyst (SnNaC-550) had spherical-homogeneous and cubic-shaped nanocrystalline particles with 5.5 nm mean particle size and a BET surface area of 81 m2/g, which resulted in 98% degradation and 84% mineralization of 50 mg/L ACT at 20 and 30 min reaction time, respectively when combined with ozonation (COP). Based on the radical scavenger experiments, •OH was the major oxidizing agent involved in the removal of ACT. LC/MS analysis showed that short-chain carboxylic acids were the main intermediates. Furthermore, the SnNaC-550 catalytic activity was preserved after four successive cycles. Collectively, the new method has the potential to efficiently synthesize stable and reusable SnO2 nanoparticles to catalyze the ozonation of ACT from aquatic environments.