Photocatalytic Degradation of Ceftriaxone Using TiO2 Coupled with ZnO Micronized by Supercritical Antisolvent Route

Abstract

Heterogeneous photocatalysis is a promising technique for removing pollutants from water. In this work, supercritical antisolvent (SAS)-micronized ZnO (ZnOSAS) is coupled with commercial anatase TiO2 (PC50) to study the photocatalytic degradation of ceftriaxone under UV and visible light. Diffuse ultraviolet–visible reflectance (UV−vis DRS) measurement revealed that the presence of ZnO leads to a slight absorption in the visible region. Wide-angle X-ray diffraction (WAXD) analysis showed the presence of both ZnO wurtzite and TiO2 anatase crystalline phases in the composite. Photocatalytic tests proved that the activity of the ZnOSAS/PC50 composite is higher than that of commercial ZnO, SAS-micronized ZnO, and PC50, allowing complete ceftriaxone degradation under UV light after only 2 min of irradiation time. In contrast, about 90% of ceftriaxone degradation is achieved after 180 min of visible-light irradiation. The photocatalytic results for an experiment carried out in the presence of probe scavenger molecules for reactive oxygen species show that hydroxyl radicals and positive holes are both reactive species involved in the ceftriaxone photocatalytic degradation mechanism. Finally, reuse cycles of the ZnOsas/PC50 composite are performed, demonstrating the stability and recyclability of the photocatalyst.

Photocatalytic Degradation of Pharmaceutical Residues from Water and Sewage Effluent Using Different TiO2 Nanomaterials

“…Among the different AOPs, photocatalysis using semiconductors such as TiO 2 represents a clean technology which has been studied and is becoming popular for the degradation of pharmaceuticals [ 8 , 11 ]. Various metal oxides such as Ga 2 O 3 [ 12 ], ZnO [ 13 , 14 ], TiO 2 [ 15 , 16 , 17 ], and In 2 O 3 [ 18 ], polymeric materials such as g-C 3 N 4 [ 19 , 20 , 21 , 22 ], and spinel structures such as CuFe 2 O 4 [ 23 ] and ZnFe 2 O 4 [ 24 ] have been used in photocatalysis technology. Notably, TiO 2 is generally regarded as the benchmark photocatalyst [ 25 ].…”