Optical Properties And Photocatalytic Activity Of Carbon Nitride Composites

About 150,000 tons of antibiotics are produced every year in our country,which is widely used to improve human and animal health,growth rate and disease prevention.Large quantities of compounds are introduced into the environment from municipal wastewater,industrial and health facilities.The presence of these drug-active compounds in the aquatic environment disrupts natural ecosystems.If these compounds are not handled properly,their accumulation will cause serious problems for microbial populations,humans and livestock.Tetracycline antibiotics in particular have attracted human attention due to their long life in water.there are some methods used to remove antibiotics in wastewater,such as adsorption,microbial degradation and electrolysis.However,these methods did not bring much progress due to the implementation of costly and poor removal efficiency.Photocatalysis degradation is a green technology that has been highly expected.although many photocatalysts have been applied to remove antibiotics from wastewater,there are still many serious problems,such as poor charge separation,weak surface adsorption,low surface area and so on.Two-dimensional（2D）-2D face-to-face photocatalysts have been prepared to degrade tetracycline hydrochloride antibiotics.this 2D-2D heterojunction shows effective enhancement of photocatalytic activity and finds the optimal loading content.degrading hydrolyze tetracycloin hydrochloride in the solution of different pH values,it is concluded that the photocatalytic activity is the highest at the neutral pH value.Adding different anions to the solution,it is found that the photocatalytic activity decreased sharply in the presence of some anions such as SO₄^2-、Cl^-、CO₃^2-、NO₃^-and PO₄^3-.To further improve the photocatalytic activity,Ag nanoparticles are loaded on the g-C₃N₄ surface,and the prepared Ag-NiO/g-C₃N₄photocatalysts shows stronger photoactivity.Amorphous CuO is considered to be an excellent cocatalyst because of its large specific surface area and superior conductivity.In this work,amorphous CuO is prepared to grow on the surface of graphitic carbon nitride（g-C₃N₄）and then applied to the photocatalytic degradation of tetracycline hydrochloride.The prepared CuO/g-C₃N₄ samples exhibit higher photocatalytic activity compared with pure phase g-C₃N₄ and CuO.And the experimental results show that the photocatalytic degradation activity is quenched in the presence of different anions such as SO₄^2-,Cl^-,CO₃^2-,NO₃^-and PO₄^3-.The photocatalytic activity is enhanced when an appropriate number of silver nanoparticles are loaded onto the optimized CuO/g-C₃N₄ composite（Ag-CuO/g-C₃N₄）surface.The results show that g-C₃N₄ co-loaded with Ag and CuO have a significant synergistic effect on photocatalytic activity.Our work may provides an effective way to prepare low-cost and efficient photocatalysts to protect our environment.