Insight into peroxymonosulfate assisted photocatalysis over Fe2O3 modified TiO2/diatomite composite for highly efficient removal of ciprofloxacin

The ternary Fe2O3/TiO2/diatomite (Fe2O3/TDE) composite was synthesized through a chemical precipitation-calcination method to boost the ciprofloxacin (CIP) degradation performance under persulfate catalysis and visible-light photocatalysis (PMS+Vis) synergistic system. It is indicated that Fe2O3 and TiO2 uniformly dispersed on the surface of diatomite, leading to the increase of active sites. Moreover, the lower recombination of electron-hole pairs promoted the photocatalytic performance and PMS activation. Therefore, the obtained Fe2O3/TDE composite (Fe2O3/TDE-5) exhibited superior degradation efficiency of CIP with the removal rate of approximately 88% under PMS+Vis system, and the degradation rate constant was 3.58 and 8.06 times higher than Vis and PMS single system, respectively. Besides, the introduction of diatomite not only enhanced the activation of PMS by superficial hydroxyl groups, but also enhanced the migration of photogenerated carriers. In addition, the radical pathway (h+, O2−, SO4− and OH) and non-radical pathway (1O2) work together for the removal of CIP. This work provides a deep insight for coupling application of photocatalysis and PMS activation for water environmental remediation.