A novel and reusable multinanozyme system for sensitive and selective quantification of hydrogen peroxide and highly efficient degradation of organic dye

For the first time, a novel multinanozyme system was used for the highly efficient bio-degradation of organic dye, malachite green, from real water media, and ultra-sensitive detection of H2O2 by the simultaneous use of MnO2- and SiO2@Fe3O4-nanozymes. The nanozymes were characterized for their size, morphology, crystalline structure, and peroxidase-like activity. Regard H2O2 detection, a linear range from 1.0-100.0 µM, and a detection limit of 0.26 µM were achieved. The method exhibited ultra-selectivity toward H2O2 detection against co-existing compounds and soluble oxygen. Regard, malachite green degradation, upon this system, the dye was degraded 99.5% within 5.0 min which shows an excellent improvement for dye removal from water media using the multinanozyme system compared to the corresponding single-nanozyme systems (50.0% after 5.0 min). The reusability studies showed that the peroxidase-like activity of the multinanozyme system was stabled for 10 and 15 reuses toward dye degradation and H2O2 determination, respectively. Kinetics and adsorption isotherms for malachite green removal using the multinanozyme system were also evaluated, revealing a pseudo-first-order kinetics and Langmuir adsorption model for dye degradation. The method was successfully applied for H2O2 quantification in milk samples and organic dye degradation from real water media.