Sonoelectrochemical degradation of aspirin in aquatic medium using ozone and peroxymonosulfate activated with FeS2 nanoparticles

Abstract

The catalytic performance of nano-${\mathrm{FeS}}_2$ in the sonoelectrochemical activation of peroxymonosulfate (PMS) and ozone to remove aspirin (ASP) was studied for the first time. The crystal structure and Fe bonds in the catalyst were confirmed through XRD and FTIR analysis. Within 30 min, ASP (TOC) was removed by 99.2 % (81.6 %) and 98.6 % (77.4 %) in nano-${\mathrm{FeS}}_2$/PMS and nano-${\mathrm{FeS}}_2$/$O_3$ sonoelectrochemical systems, respectively. Water anions, especially${\mathrm{HCO}}_3^{-}$ (almost 50 %), had an inhibitory effect on ASP removal. The probes confirmed that ${\mathrm{SO}}_4^{•-}$and ${\mathrm{HO}}^{•}$ were the key to ASP degradation in nano-${\mathrm{FeS}}_2$/PMS and nano-${\mathrm{FeS}}_2$/$O_3$ systems, respectively. The effective activation of oxidants due to the ideal distribution of ${\mathrm{Fe}}^{2+}$ by catalyst was the main mechanism of ASP removal, in which electric current (EC) and ultrasound (US) played a crucial role through the recycling of Fe ions, dissolution and cleaning of the catalyst. LC-MS analysis identified thirteen byproducts in the ASP degradation pathways. The energy consumption of the proposed sonoelectrochemical systems was lower than previous similar systems. This study presented economic and sustainable hybrid systems for pharmaceutical wastewater remediation.