An environmentally friendly chitosan-loaded BiOCOOH/BiYO photocatalyst for efficient photocatalytic degradation of tetracycline.

In this work, the photocatalyst BiOCOOH/BiYO/Chitosan (CS) was prepared by using CS as the carrier and adsorbent. The performance of the material was studied through the photocatalytic degradation of tetracycline (TC) in water. Theoretical calculations and experiments demonstrate that the formation of BiOCOOH/BiYO heterojunctions improves the separation of photogenerated carriers and the absorption of visible light by the material. The introduction of CS improves the difficulties in material recovery, demonstrating exceptional degradation ability for TC under the action of adsorption and photocatalysis. Adsorption kinetics studies indicate that the adsorption of TC by BiOCOOH/BiYO/CS fits the pseudo-second-order model better, while the adsorption at different concentrations of TC is more suitably described by the Freundlich isotherm model. The synthesis of BiOCOOH/BiYO/CS was confirmed by the analysis of XRD, XPS, and FTIR. UV-vis DRS showed that the synthesis of BiOCOOH/BiYO/CS broadened the range of light absorbed by the material. The testing results of PL and transient photocurrent density indicate that BiOCOOH/BiYO exhibits a higher efficiency in separating photogenerated charge carriers. After 5 cycles of reuse, the degradation efficiency can still reach 90 % of the initial efficiency, indicating that CS-based photocatalytic composite catalysts have practical application potential in the field of water pollution treatment.