Visible-light photocatalytic diclofenac removal by tunable vanadium pentoxide/boron-doped graphitic carbon nitride composite

The growing consumption of pharmaceutical products is taking a heavy toll on conventional wastewater treatment plants, the incomplete or no-removal of pharmaceutical species. Photocatalysis can be implemented as a refining step in treatment trains to mineralize these pharmaceuticals. In this study, vanadium pentoxide (V2O5) was integrated into boron-doped graphitic-carbon nitride (BCN) to produce visible-light-active vanadium oxide/boron co-doped graphitic-carbon nitride (V2O5-BCN) photocatalysts wherein graphitic carbon nitride (g-C3N4) was produced by thermal poly-condensation of urea. The photocatalysts were characterized and their performance under visible light irradiation was evaluated using diclofenac (DCF) as a representative pharmaceutical active compound. The effects of dopant amount, photocatalyst dosage, initial DCF concentration, solution pH and presence of anions on DCF removal were examined. Results showed that DCF adsorption on V2O5-BCN photocatalysts conformed to the pseudo-second order kinetic model while DCF photodegradation followed the pseudo-first order reaction kinetics. The photocatalysts were found to be stable and reusable. DCF removals reached 100% in < 105 min under visible light irradiation. Overall, the as-synthesized V2O5-BCN heterojunction proved to be a promising photocatalyst for sustainable and low-cost treatment of pharmaceutical-contaminated wastewaters.

Automated summary

In this study, V2O5-BCN photocatalysts were synthesized for the removal of pharmaceutical contaminants in wastewater, achieving a 100% removal rate of DCF. The photocatalysts showed stability and reusability, making them promising for sustainable and low-cost treatment of pharmaceutical-contaminated wastewaters.