Study On Adsorption And Catalytic Oxidative Degradation Of Tetracycline Wastewater By Sludge Activated Carbon And Its Composite Materials

As the promotion of urbanization and the development of economy in our country,the quantity of wastewater treatment have increased continuously,As a by-product of the sewage treatment process,the discharge of sludge has increased dramatically.The sludge contains many pathogenic microorganisms,parasitic eggs and heavy metals.If the sludge is not handled properly,it may cause secondary pollution.Tetracycline is one of the most commonly used antibiotics in the world,but more than 70%of its dosage is discharged into the environment because it cannot be absorbed,whether it is harmful to human health or the environment.In this paper,activated sludge activated carbon and its composite materials were prepared by using urban waste sludge as raw materials,and the adsorption and catalytic oxidation degradation properties of these materials to tetracycline were discussed,in order to develop excellent-performance tetracycline wastewater treatment functional materials.Below are key research findings.1.Using municipal waste sludge as raw material,ZnCl₂ activation method was used to prepare sludge activated carbon?SAC?.Through the optimization of preparation conditions,it was found that the best preparation conditions for SAC were:zinc chloride concentration of 0.7 mol/L,sludge dosage of 1 g,zinc chloride dosage of 9 mL,carbonation time of 30 min,and carbonization temperature of 600?.SAC characterization analysis results show that the prepared SAC has a well-developed pore structure,mostly in the shape of tube,arranged in an orderly manner,and mainly mesopores.Examining the effect of different conditions on the adsorption of tetracycline by SAC,it was found that when the initial concentration of tetracycline solution was 30 mg/L,the pH was 6.0,and the SAC dosage was 6 g/L,the adsorption rate of tetracycline by SAC reached 86.38%.The adsorption process of tetracycline by SAC fits the quasi-second-order kinetic model and Freundlich adsorption isotherm equation,indicating that the adsorption process is mainly chemical adsorption,and it occurs in the single molecular layer.Material reuse experiments show that SAC materials can be reused multiple times.2.Using SAC as a carrier,a SAC/CeO₂ composite material was prepared.SAC/CeO₂ composite material has simulated oxidase activity.Investigating the effect of different conditions on the catalytic oxidation degradation of tetracycline,it was found that the mass ratio of SAC and CeO₂ was 5:1,the initial concentration of tetracycline solution was 20 mg/L,pH was 8,and the dosage of SAC/CeO₂ composite material was1.0 g/L,the catalytic degradation efficiency of SAC/CeO₂ composites on tetracycline reached 85.5%.3.By adding graphene oxide?GO?,a SAC/CeO₂-GO composite material was prepared.The SAC/CeO₂-GO material has simulated oxidase activity.The effects of the amount of GO added,the amount of SAC/CeO₂-GO composite added,the initial concentration of tetracycline solution,and pH on the catalytic oxidation degradation performance were investigated.The results showed that when the mass ratio of SAC/CeO₂:GO was 9:1,the initial concentration of the tetracycline solution was 30mg/L,the pH was 6,and the dosage of the composite material was 0.5 g/L,the catalytic oxidation efficiency of the composite material on tetracycline reached 92.4%.