Photocatalytic degradation of sulfamonomethoxine by mesoporous phosphorus-doped titania under simulated solar light irradiation

Chemosphere. 2021 Dec:285:131553. doi: 10.1016/j.chemosphere.2021.131553. Epub 2021 Jul 12.

Abstract

Photocatalytic degradation of sulfamonomethoxine (SMM) by mesoporous phosphorus-doped TiO2 (P-TiO2) was studied under simulated solar light irradiation. The morphological structure and chemical composition of P-TiO2 were analyzed by XRD, SEM, HRTEM, BET, XPS and FTIR. Using the central composite design (CCD) of response surface methodology (RSM), the degradation of SMM was investigated with a range of antibiotic concentrations (4-8 mg L-1), catalyst dosages (400-900 mg L-1), P doping amounts (5-15 wt %) and irradiation time (90-150 min). The Ti-O-P bond formed during the calcination of TiO2, thereby generating plate-like P-TiO2, where P was uniformly distributed. Phosphorus doping can stabilize anatase TiO2, which has a larger specific surface area and a lower average particle and pore size than bare TiO2. The result obtained from the RSM model showed a significant correlation between the predicted values and the experimental results of SMM degradation (P < 0.05). Under the optimal experimental conditions (antibiotic concentration = 6 mg/L, catalyst dosage = 800 mg/L, P doping = 5 wt% and irradiation time = 90 min), the degradation rate of SMM was 99.51%, and the TOC was 50%. Toxicity showed a considerable reduction towards Vibrio-qinghaiensis sp.-Q67 after SMM photocatalytic degradation. Through free radical capture experiments, LC-MS detection and DFT calculations, the possible photocatalytic degradation mechanism of SMM using P-TiO2 as the catalyst was revealed.

Keywords: DFT calculation; Degradation pathway; RSM optimization; Toxicity; Vibrio-qinghaiensis sp.

MeSH terms

  • Catalysis
  • Light
  • Phosphorus*
  • Sulfamonomethoxine*
  • Titanium

Substances

  • titanium dioxide
  • Phosphorus
  • Titanium
  • Sulfamonomethoxine