The enhanced catalytic potential of sulfur-doped MgO (S-MgO) nanoparticles in activation of peroxysulfates for advanced oxidation of acetaminophen

Abstract

The peroxymonosulfate (PMS) and peroxydisulfate (PDS) were activated using plain and S-doped MgO (S-MgO) for oxidation of acetaminophen (ACT) in the contaminated water. The findings indicated that S-MgO was more efficient than plain MgO in activating the oxidants and that PMS was much better activated than PDS using S-MgO. The complete degradation and significant mineralization (up to 62.4%) of 50 mg/L ACT could be achieved in the S-MgO/PMS process using 1.4 mM PMS within a reaction time of 30 min and 60 min, respectively. Both SO4·- and HO· species were simultaneously generated in the S-MgO/PMS process with the contributions of 73.8% and 26.2%, respectively, in the ACT removal attained in the process. ACT removal in the S-MgO/PMS process was not considerably affected by the solution pH between 4 and 10 and the maximum ACT removal of 93.4% was achieved at the neutral condition and optimum PMS to catalyst ratio of 0.07 mM L/g. The performance of S-MgO/PMS process for removal of ACT was not affected by the presence of conventional anions in natural waters. The pathway of ACT degradation in the S-MgO/PMS process was proposed based on the Liquid chromatography–mass spectrometry (LC/MS) analysis of the effluent. Accordingly, the S-MgO is a very active catalyst to activate the PMS for simultaneous generation ofSO4·- and HO· reactive species hence S-MgO/PMS process is an emerging AOP for high rate degrading the pharmaceutical compounds present in contaminated waters.