Development of ZnFe2O4 nanoparticle functionalized baker's yeast composite for effective removal of methylene blue via adsorption and photodegradation

In the present work, the superparamagnetic ZnFe2O4 nanoparticle functionalized baker's yeast (ZnFe2O4-yeast) composite was prepared by a facile one-pot sonication procedure, and then investigated its adsorption and photodegradation potential for methylene blue (MB). The ZnFe2O4-yeast composite was studied by SEM, EDS, VSM, XPS and FTIR, respectively. All characteristic results present that the magnetic ZnFe2O4 nanoparticle in-situ formed on yeast surface, and some surface functional groups (e.g., hydroxyl and carboxyl) on yeast spontaneously exposed. The adsorption experiment displays that MB sorption amount of ZnFe2O4-yeast composite significantly improved compare to pristine yeast, and its adsorption process can be well described by pseudo-second order kinetic model and Freundlich isotherm. In addition, the ZnFe2O4-yeast composite presents an excellent photodegradation property for MB under UV light. The photodegradation tests, as well as FTIR and XPS analysis confirmed that high MB adsorption and photodegradation properties of ZnFe2O4-yeast composite are mainly attributed to the synergistic effect of functional groups and formed ZnFe2O4 nanoparticle on yeast surface. Overall, this study indicates that ZnFe2O4-yeast composite is promising as one of the alternative adsorption and photodegradation materials for dye wastewater treatment.