Construction Of Hierarchically Porous Materials And Their Applications In Tetracycline Monitoring

Tetracycline antibiotics are broad-spectrum antibiotics that can flow into water and soil through the food chain and endanger human health.Therefore,it is necessary to find a way to efficiently detect antibiotics in the environment.Thin film diffusion gradient technology is an in-situ monitoring technology that can quantitatively determine the concentration of metal ions and organic substances in water.The bound phase is separated from the bulk solution by an ion-permeable membrane or hydrogel to control ion exchange for on-site quantitative separation and accumulation.Compared with the traditional sampling method,this technology is suitable for on-site monitoring,high reliability and strong applicability.In this paper,the three-dimensional SiO2-TiO2 hierarchically porous(Including micropores-mesopores-macropores and macropores between fibers)aerogel materials were constructed by electrospinning technology based on the principle of inorganic ester solidifying and electrostatic repulsion.The material has a high porosity of more than 99%,an ultra-low density of 29.9 mg·cm-3,good compressibility and good thermal insulation.The material was used as the binding phase of the DGT device,and the nylon membrane was used as the diffusion phase of the DGT device to verify its feasibility and establish a complete method for collecting tetracycline.The diffusion coefficient of tetracycline was determined by diffusion cell D=2.42×10-6 cm2·s-1.The effectiveness and influencing factors(including concentration,pH,ionic strength,humic acid)of tetracycline collected by hierarchically porous SiO2-TiO2 gel-DGT were studied,It is proved that the collection of tetracycline is almost unaffected by the multi-stage pore SiO2-TiO2 gel-DGT device,when the ionic strength is in the range of 0.001～1000 mmol·L-1;the pH is in the range of 4～7;the humic acid concentration is 0-50 mg·L-1.The effectiveness of the application in the South Lake water body was verified by the method of spiked recovery,the resulting of CDGT/C meets the ideal range for DGT monitoring.Therefore,the hierarchically porous SiO2-TiO2 material prepared in this paper as a binding phase of DGT device provides a valuable reference for monitoring tetracycline hydrochloride remaining in water.