Developing novel photoactive bimetal Cr/Ag-codoped CeO2 nanozymes with synergistic activity toward biophotodegradation of organic dyes from real water media and textile wastewater

A novel biophotodegradation method of organic dyes was developed using photoactive bimetal Cr/Ag-codoped CeO₂ nanozymes with synergistic activity toward dye biophotodegradation from real water media and textile wastewater. The photoactive bimetal Cr/Ag-codoped CeO₂ nanozymes were synthesized and then comprehensively identified using several characterization methods. The developed bimetal Cr/Ag-codoped CeO₂ nanozymes revealed enhanced peroxidase-like activity. The introduced bimetal Cr/Ag-codoped CeO₂ nanozymes exhibited 6.66-order, 3.53-fold, and 2.0-order higher enzyme-like activity than the CeO_2, Ag-CeO_2, and Cr-CeO₂, respectively, revealing the synergistic effect of bimetal-codoping on their catalytic activity. The photonanozymatic activity of the nanozymes was found to be 1.47-fold and 2.48-order higher than their nanozymatic and photocatalytic activity, respectively. Hence, they were applied for environmental mineralization applications via biophotodegradation of methylene blue. The effective factors on the yield of biodegradation were optimized by the one-factor-at-a-time method, providing maximal biophotodegradation of 99.95 % within 7.0 min. The storage and cycling stability of the developed photoactive bimetal Cr/Ag-codoped CeO₂ nanozymes were assessed, exhibiting that they are sable for at-least 30 days and 10 recycles without any change in their activity. The method was then practically applied for the treatment of water media (biophotodegradation, 98.7–99.6 %) and textile wastewater (biophotodegradation, 89.6–99.5 %).