Valorization of hazardous chrome tanned leather buffing waste for the production of Cr2O3/carbon/TiO2 composite semiconductors with the removal of chlorophenol from its wastewater.

[Display omitted] • A new waste derived Cr 2 O 3 /carbon/TiO 2 nanocomposite was successfully synthesized. • TiO 2 impregnation influence on the degradation of chlorophenol was investigated. • The carbon act as a co-catalyst for efficient separation electron and hole pairs. • Synergistic effect endowed Cr 2 O 3 /carbon/TiO 2 composite with improved TiO 2 addition. Highly stable semiconducting, photocatalytic Cr 2 O 3 /carbon/TiO 2 composites have been successfully synthesized from toxic chrome-tanned buffing dust. The presence of Cr 2 O 3 (eskolaite) and impregnation of TiO 2 (anatase) were confirmed through XRD and XPS analysis. Moreover, it was observed that Cr 2 O 3 /carbon/TiO 2 composite bandgap decreased compared to TiO 2. The synergetic effect of Cr 2 O 3 /carbon/TiO 2 composite was evaluated by degradation of 2-chlorophenol (2-CP) and 4-chlorophenol (4-CP) using light energy sources of 254 nm and 365 nm. Nearly 100% of 2-CP and 4-CP was degraded within 30 min following first-order kinetics, and the nanocomposite (10% ACTi) showed seven and two times higher activity than TiO 2 and Cr 2 O 3 /carbon materials. Degradation efficiency was further confirmed by HPLC and CV analysis. The higher degradation activity noted was attributed to the generation of hydroxyl radicals, which was confirmed by fluorescence spectroscopy analysis. Furthermore, the nanocomposite is highly stable even after 96 h of reaction, which was confirmed by XRD analysis. The results conclude that waste materials can be utilized for synthesizing semiconducting photocatalytic materials. [ABSTRACT FROM AUTHOR]