From core-shell like structured zirconia/magnetite hybrid towards novel biocatalytic systems for tetracycline removal: Synthesis, enzyme immobilization, degradation and toxicity study

Presented research deals with novel approach for synthesis of zirconia/magnetite hybrid with core-shell like structure, for effective enzyme immobilization. The material was obtained via two stage sol-gel method, including firstly preparation of magnetite followed by its merging with zirconia particles during in situ synthesis of ZrO2. As prepared zirconia/magnetite hybrid was thoroughly characterized in order to examine its usability as support for laccase immobilization. The effectiveness of enzyme immobilization as well as characterization of obtained biocatalytic system were presented. The activity tests of ZrO2-Fe3O4-enzyme showed high catalytic activity over wide pH and temperature range. The utilitarian aspect of the research was related to evaluation of application potential of as prepared biocatalytic system towards degradation of tetracycline from model wastewaters. It was shown that over pH range 4–7 and temperature from 25 to 45 °C, over 80% of tetracycline was removed from 1 mg/L solution. Additionally, the reusability study of the biocatalyst showed that even after ten repeated degradation trials, still over 80% of antibiotic was removed. The products of tetracycline conversion were also identified. Based on collected experimental data, the mechanism of tetracycline degradation was proposed and discussed.