Removal of aspirin from aqueous solutions using graphitic carbon nitride nanosheet: Theoretical and experimental studies

This study evaluates the adsorption of acetylsalicylate (aspirin) from aqueous solution on the surface of graphitic carbon nitride nanosheet (g-C3N4). We have considered both theoretical and experimental studies about the aspirin removal. In the experimental study, the effect of pH, aspirin and adsorbent doses, temperature, time and degradation under visible light were considered. The adsorption is an endothermic process and follows from the Langmuir's model. In the theoretical study, the graphitic carbon nitride nanosheet as an interesting material investigated by first-principle calculations, the Quantum Espresso package. Optimized geometric of the g-C3N4 nanosheet, adsorption energy Eads, HOMO and LUMO energies, band gap energy Eg, E-FL and DOS as well as PDOS plots were obtained. The binding energy of water was obtained on the g-C3N4 nanosheet. By adsorption of aspirin, the HOMO/LUMO energy gap of the adsorbent, the graphitic carbon nitride nanosheet, is reduced to 1.16 eV. The results obtained from the experimental and theoretical analyses showed that the removal of aspirin on the surface of the graphitic carbon nitride nanosheet is easy treatment, eco-friendly and high yield.