Synthesis of CoCrFeO₄-chitosan beads sun-light-driven photocatalyst with well recycling for efficiently degrading high-concentration dyes

It is highly desired to develop an efficient large surface area CoCrFeO₄-based beads sun-light driven photocatalysts with excellent recycling features for degrading high-concentration dyes. Herein, a novel CoCrFeO₄ oxide nanoparticles have customarily been synthesized by the combination of three metals (Co, Cr and Fe) via co-precipitation method in aqueous solution and then millimeter-scale CoCrFeO₄ oxide chitosan-composite beads (CoCrFeO₄-CB) were prepared by incorporating the CoCrFeO₄ in chitosan polymer in basic medium, which makes the adsorbent easier to separate. The number of optimized nanocomposite beads used for the removal of high-concentration dyes displays 5-time photoactivity enhancement under sun-light irradiation compared to pristine CoCrFeO₄. Based on the fluorescence spectra related to the formed [rad]OH amounts, temperature-programmed desorption and electrochemical results, it is deduced that the unprecedented photocatalytic activities are mainly attributed to the large surface area, and enhanced charge separation from the chitosan as well as its promotion effects on O₂ activation. Influencing factors that effect the photocatalytic efficiency of dyes, such as catalyst dose, dyes concentration, time, and the light source was also studied. More importantly, after five catalytic cycles, no evident deactivation was observed, suggesting the satisfactory stability of the investigated photocatalyst. Also, large numbers of superoxides radicals form which is the main active species participate in the degradation of acid black were analyzed using a radical trapping experiment. It is expected that our work could render navigated information for steering toward the design and applications of the CoCrFeO₄-based photocatalyst with sun-light utilization for environmental remediation.