Electrically enhanced adsorption and photocatalytic properties of g-C3N4/TiO2 heterostructure for removal of tetracycline in water: A study by molecular dynamics simulation and experiment

[Display omitted] •EF reduces the number of water molecules near the surface of g-C3N4/TiO2 heterostructure.•EF enhances the adsorption of TC in water by g-C3N4/TiO2 heterostructure.•EF enhances the light absorption property of g-C3N4/TiO2heterostructure.•EF enhances the photocatalytic degradation efficiency of TC by g-C3N4/TiO2 heterostructure. Here, molecular dynamics (MD) simulations and experimental studies were carried out to investigate the effect and mechanism of external applied electric fields on the adsorption efficiency of g-C3N4/TiO2 heterostructure for removing tetracycline (TC) from water. The MD simulation results indicate that the electric fields in the X and Y directions have little effect, while the electric field in the Z direction has a significant impact on the adsorption system. The Z direction electric field significantly reduces the number of water molecules near the surface of the heterostructure, improves the adsorption energy between the heterostructure and TC molecules, and thereby enhances the adsorption effect. The experimental research results show that the removal rate of tetracycline increases from 26 % to 33 % in 90 min when an electric field of 3000 V/m is applied, which indicates that the presence of an external electric field can improve the adsorption and removal performance of g-C3N4/TiO2 heterostructure for TC in water, and verifies the research conclusion of MD simulations. Alkaline conditions are more conducive to the removal of TC. In addition, applying an external electric field can effectively improve the light absorption performance of heterostructures, thereby enhancing the photocatalytic degradation efficiency of TC.