Study On The Performance And Mechanism Of Three-dimensional Graphene Composites In Repairing Antibiotic-contaminated Water

There were many kinds of antibiotics in the environment,and they were attracting more and more attention as"emerging pollutants".In this study,tetracycline(TC)and rofloxacin(CIP)were used as research objects to prepare iron-based three-dimensional graphene and copper,respectively.Based on the three-dimensional graphene composite material,the antibiotics in the water were removed by adsorption and oxidation.At the same time,the performance and mechanism of the composite material to adsorb TC and CIP and the mechanism of catalytic activation of persulfate(PDS)to oxidize and degrade TC were investigated as the following content:(1)The prepared iron-based 3D graphene(3D-rGO-Fe₃O₄)and copper-based3D graphene(3D-rGO-Cu)were characterized.The characterization results showed that both 3D-rGO-Fe₃O₄and 3D-rGO-Cu had a network structure of pores,and iron-based 3D graphene could effectively inhibit the agglomeration phenomenon,making Fe₃O₄uniformly attached to the pores of three-dimensional graphene.However,the copper on 3D-rGO-Cu was agglomerated on the graphene surface,and the hardness of 3D-rGO-Cu was poor.The subsequent experiments should solve the agglomeration and hardness problems.(2)The competitive adsorption mechanism of graphene materials was discussed and the comprehensive influence of multiple elements was analyzed.The experimental results show that tetracycline was more easily adsorbed at high temperature,while temperature had little effect on the adsorption of ciprofloxacin.Tetracycline was more easily adsorbed under acidic conditions,and ciprofloxacin adsorption was suitable for neutral conditions.The adsorption of ciprofloxacin and tetracycline decreased significantly during the composite adsorption.Repeated experiments were carried out on the materials,and the integrity of the materials was maintained,and the adsorption effect only decreased slightly.The fitting results showed that 3D-rGO-Fe₃O₄was adsorbed by chemisorption and single molecular layer for both antibiotics,and the diffusion within particles was the main reason affecting the adsorption rate.(3)The oxidation degradation of tetracycline by 3D-rGO-Fe₃O₄by catalytic activation of PDS was studied to investigate different influencing factors and explore the oxidation degradation performance of composite materials.The experimental results show that the 3D-rGO-Fe₃O₄composite catalyst has good stability.The degradation rate of tetracycline increased with increasing temperature.When the initial concentration of tetracycline was 100 mg/L,the rotation speed was 180 rpm,the material mass was 0.05 g,the p H was 3,the PDS concentration was 6 mmol/L,and the temperature was 25?,3D-rGO-Fe₃O₄had the best performance after catalytic activation of PDS,and the degradation rate of tetracycline reached the maximum.In addition,Cl^-,NO^3-,CO₃^2-and HCO₃^-had a weak inhibitory effect on tetracycline degradation,while Cu²⁺had a promoting effect.(4)The oxidation degradation of tetracycline by catalytic activation of PDS by cupr-based 3D graphene was investigated.According to the analysis,the initial indicator is 100 mg/L,and the actual speed indicator is 180 rpm,the material mass was0.03 g,the p H was 3,the PDS concentration was 4 mmol/L,and the temperature was25?,the catalytic activation performance of 3D-rGO-Cu was the best,and the removal rate of tetracycline was 98%.Cl^-and CO₃^2-had little effect on the system,but humic acid had great inhibitory effect on the system.The removal rates of ciprofloxacin,sulfadiazine and p-nitrophenol by 3D-rGO-Cu were all over 89%.