Study On The Visible Light Photocatalysis Degradation Of Sulfadiazine On Hollow C,N-TiO₂@C Molecular Imprinting Microspheres

Discarded syrup wastewater was used as a carbon source in this research,the method of hydrothermal condensation was used to prepare syrup carbon nanospheres?DDSC?.Then,the sol-gel method was used to synthesize and codope the C,N-TiO₂layer which was on the surface of DDSC.After calcinating at high temperature,the DDSC was removed and then we got the hollow composites?Hollow C,N-TiO₂@C?.The next hydrophilic and molecular imprinted layer was formed on the surface of Hollow C,N-TiO₂@C with sulfadiazine as a template molecule,resorcinol and melamine as dual-function monomers,formaldehyde and TiO₂ as crosslinking agents to prepare Hollow C,N-TiO₂@C-MIP.The prepared DDSC,Hollow C,N-TiO₂@C and Hollow C,N-TiO₂@C-MIP were used to study on the removal effectiveness of sulfadiazine pollutants,respectively.DDSC owns a large specific surface area,high porosity,and much oxygen or nitrogen-containing groups?such as amino,carboxyl,hydroxyl,et al.?The results of adsorption experiment from sulfadiazine?SDZ?antibiotics showed that the maximum adsorption of DDSC for SDZ is 20.12 mg·g^-1.The amino,carboxyl,and hydroxyl groups on the surface of DDSC could improve the DDSC adsorption capacity because the amino group,carboxyl group and hydroxyl group on the surface of DDSC can be easily combined with the amino group and aromatic ring on the surface of SDZ by hydrogen bond and?-?bond.Hollow C,N-TiO₂@C is generally less dense,high instability,and dispersion.The co-doping effect of carbon?C?and nitrogen?N?can promote the absorption of visible light and the separation of photo-generated electron-hole pairs to improve the photocatalytic activity of Hollow C,N-TiO₂@C.In addition,the hollow structure contributes to absorbing sulfonamides and visible light.When it is illuminated by the visible light,the degradation rate of Hollow C,N-TiO₂@C for sulfadiazine within 140min was 97.28%,higher than that of TiO₂?70.04%?.Hollow C,N-TiO₂@C-MIPs have good hydrophilicity,reusability,and stability.Hollow C,N-TiO₂@C-MIPs could increase the removal rate of target pollutants through targeted identification,adsorption and photocatalytic degradation.When it is illuminated by the visible light,Hollow C,N-TiO₂@C could achieve the purpose of in situ regenerating by photocatalytic degradation of targeted sulfadiazine pollutants.In the pseudo-first-order kinetics study,the pseudo-first-order kinetic constant of Hollow C,N-TiO₂@C-MIPs is 0.01815 min^-1,which is 1.88 or 3.31 times larger than Hollow C,N-TiO₂@C(0.00964 min^-1)and TiO₂(0.00548 min^-1).For this research on the choice of Hollow C,N-TiO₂@C-MIPs to SDZ,we used Ciprofloxacin?CIP?as a competitive pollutant to form a mixed binary system,the results indicated that the removal efficiency of SDZ using Hollow C,N-TiO₂@C-MIPs reached up to 93.56%,which was higher than that of CIP by 45.01%.