Mesoporous semi-ionic F-doped g-C3N4 as efficient photocatalyst for tetracycline removal under visible light

The removal of refractory contaminants such as tetracycline (TC) antibiotics from wastewater has drawn a lot of interest. Semi-ionic mesoporous F-doped g-C3N4(e.g. GCN-F0.50) photocatalysts were successfully fabricated with different doping amounts. The GCN-F0.50 shows the highest TC removal performance under visible light irradiation (λ > 420 nm), which is 99.8% (0.0207 min−1) of removal in 180 min. The highest COD removal of TC was 75.9% using GCN-F0.50 photocatalyst. This is because the semi-ionic nature of the C-F bond has high polarity, which is capable of promoting good charge separation and migration. It was found that GCN-F0.50 provides a high mesoporous surface area (79.66 m2/g) to allow more TC pollutants to be photodegraded on the surface. In addition, the optical absorption is enhanced due to bandgap narrowing (2.55 eV). This work provides a highly efficient and good reusability photocatalyst for TC removal based on F-doped g-C3N4.