Efficient identification and degradation of tetracycline hydrochloride from water by molecularly imprinted core–shell structured SiO2@TiO2

Abstract

Antibiotics have emerged as a new pollutant that is low in concentration and biologically persistent in water. Photocatalysis is a new water treatment technology, and has shown significant promise for the treatment of hard-to-degrade pollutants. In this work, core–shell structured molecularly imprinted TiO₂ was prepared by the Stöber method and the sol–gel method for efficient identification and preferential degradation of tetracycline hydrochloride. The characterization results of XRD, SEM, TEM, XPS, and FT-IR showed the successful synthesis of core–shell structured molecularly imprinted TiO₂ and imprinted cavities. Core–shell structured molecularly imprinted TiO₂ exhibits higher adsorption capacity, selectivity, and photodegradation performance for template molecules. The degradation rate of tetracycline hydrochloride was 82.18% under 60 min of light irradiation. The enhanced adsorption capacity and selectivity can be attributed to the chemical interaction between the target molecule and the imprinted cavity as well as the size matching between the imprinted cavity and the target molecule. The primary active species and degradation mechanism in the photodegradation process were analyzed via radical capture experiments. The prepared core–shell structured molecularly imprinted TiO₂ has the advantages of high removal capacity, high stability, and environmental friendliness, and has widespread applications in water treatment and water environment remediation, especially when persistent low-concentration pollutants are involved.