Adsorption of Organic Dyes by TiO2@Yeast‐Carbon Composite Microspheres and Their In Situ Regeneration Evaluation

TiO2@yeast‐carbon microspheres with raspberry‐like morphology were fabricated based on the pyrolysis method. The obtained products were characterized by field emission scanning electron microscopy (FE‐SEM), energy dispersive spectrometry (EDS), and X‐ray diffraction (XRD). Effects of initial dye concentration and contact time on adsorption capacity of TiO2@yeast‐carbon for cationic dye methylene blue (MB) and anionic dye congo red (CR) were investigated. Experimental data were described by Langmuir, Freundlich, Temkin, and Koble‐Corrigan isotherm models, respectively. It was found that the equilibrium data of MB adsorption were best represented by Koble‐Corrigan, and CR adsorption was best described by both Freundlich and Koble‐Corrigan isotherm models. The kinetic data of MB and CR adsorption fitted pseudo‐second‐order kinetic model well. The results demonstrated that TiO2@yeast‐carbon microspheres achieved favorable removal for the cationic MB in comparison with that for the anionic CR. In addition, regeneration experimental results showed that TiO2@yeast‐carbon exhibited good recycling stability, reusability, and in situ renewability, suggesting that the as‐prepared TiO2@yeast‐carbon might be used as the potential low cost alternative for recalcitrant dye removal from industrial wastewater. One possible mechanism for regenerating dye‐loaded TiO2@yeast in situ was also proposed.