Design And Synthesis Of Functional Mesoporous Composites And Their Adsorption Of Antibiotic Pollutants In Water

Antibiotic is a new and important type of environmental pollutant,which has posed a serious threat to human health and ecosystem.At present,many methods have been used to remove antibiotics from water,such as chlorination,advanced oxidation technology,biodegradation,adsorption and so on.Among these methods,adsorption method has attracted more and more attention due to its advantages such as simple operation,low cost,high efficiency and absence of toxic by-products.Mesoporous silica is widely used for adsorption and removal of inorganic and organic harmful pollutants due to its high specific surface area,large pore volume,regular controllable pore diameter and interconnected frame and other advantages.However,because of the special nature of antibiotics,the removal ability of unfunctionalized mesoporous silica to antibiotics is limited.In order to obtain adsorption materials with better performance,in this paper,we designed and synthesized several new mesoporous silica composites and studied their antibiotic adsorption performance.This paper mainly consists of the following two parts:Part I:the magnetic core-shell mesoporous silica composites modified by cyclodextrin were prepared by combining solvent thermal method,sol-gel method,template method and surface modification method.Fe₃O₄@SiO₂@mSiO₂-CD with spherical morphology and good dispersibility,vertical and radial open mesoporous channel to provide a lot of space for adsorption of antibiotics,the surface of the cyclodextrin modified with antibiotic molecules can form between the van der Waals force,hydrogen bond,electrostatic interactions,hydrophobic effect and three-dimensional steric multiple interactions,such as improving material affinity adsorption of antibiotics at the same time,the material can be separation and recovery through additional magnetic field effect,its maximum adsorbance of doxycycline hydrochloride is 78 mg/g,after repeated recycling remains good stability.The second part:using sol-gel method and hydrothermal method combined with the preparation of mesoporous silica-zinc oxide composite mSiO₂-ZnO,the synthesis method simplifies the existing the synthesis of mesoporous composite material steps,but also keep the concreted complete high specific surface area is open,the introduction of the ZnO effectively regulate the surface properties of materials,provide more active adsorption sites for antibiotics.The results showed that the adsorption equilibrium of 100 mg/L doxycycline hydrochloride solution by mSiO₂-ZnO was achieved in only 90 min,and the maximum adsorption capacity of mSiO₂-ZnO was 104 mg/g.Both physical and chemical adsorption played roles in this system.