Structure And Properties Of Granular Salix Psammophila Activated Carbon Modified By Ag And N Co-doped TiO₂

In this study,silver and nitrogen co-doped TiO₂loaded granular activated carbon was prepared from Salix psammophila with different diameters.This thesis mainly explores the influence of photocatalytic degradation and activated carbon adsorption performance on sample regeneration performance,and optimizes the modification loading and activation process of photocatalyst;The regeneration mechanism was revealed by analyzing the photocatalytic activity and structure of modified TiO₂.The results show that:1.the regeneration performance of the sample increases with the decrease of particle size,and first increases and then decreases with the increase of phosphoric acid concentration,activation temperature,activation time and TiO₂,Ag and n contents.Optimal activation process:0.7mm particle size,20%phosphoric acid concentration,700℃ activation temperature,1.5h activation time,and optimal loading process:1.2g TiO₂,0.08g Ag,1.5g N loading to 0.4g activated carbon.2.TiO₂is incompletely coated on the surface of AC（activated carbon）in the form of thin film,with only anatase crystal structure,and the mass content is 2-7%.3.Ag exists in the form of silver;Ti exists as Ti⁴⁺.N forms Ti-O-N bond in TiO₂lattice,and P forms Ti-O-P bond in TiO₂lattice.Doping Ag and N increases the content of oxygen-containing functional groups in samples.The effect of Ag doping on electron-hole recombination of TiO₂is lower than that of n,and the effect of Ag and n co-doping on electron-hole recombination is the best.The band gap value of N-doped is 0.7 e V,that of Ag-doped is 0.5 e V,and that of Ag-N co-doped is only 0.4 e V.4.The micropores,mesopores and total pores of N-doped samples increased,while those of Ag-doped samples decreased.The micropores,mesopores and total pores of the co-doped Ag and N samples are all between the single doped samples.5.Co-doped samples have developed pores and rich surface oxygen-containing functional groups,and have excellent adsorption performance for pollutants;Under the combined action of C,P,N and Ag,the visible light photocatalytic activity of TiO₂was significantly improved.Therefore,efficient regeneration of AC（activated carbon）is realized.