Ti-doped Zr-UiO-66-NH2 boosting charge transfer for enhancing the synergistic removal of Cr (VI) and TC-HCl in wastewater

The pollution of hexavalent chromium (Cr (VI)) and tetracycline hydrochloride (TC-HCl) in water environment is considered to be an urgent environmental problem. However, designing and preparing photocatalysts that can effectively remove these contaminants remains a challenge. Bimetallic metal organic framework (MOFs) Ti-doped Zr-UiO-66-NH2 (UiO = University of Olso) Tiα-Zr1-α-UiO-66-NH2 were prepared for the simultaneous removal of Cr (VI) and TC-HCl. The experimental results of photocatalytic performance show that the Cr (VI) removal rate by Ti0.4-Zr0.6-UiO-66-NH2 in single and mixed systems reach 80.9% and 99.8%, which are 1.1 and 1.4 times higher than Zr-UiO-66-NH2, respectively. The BET results confirm that the specific surface area is effectively increased due to Ti doping, which further exposes more reaction active sites. Simultaneously, the MMCT process from Zr to Ti promotes the transfer of photogenerated carriers and suppresses their recombination. The DFT calculation results demonstrate that TiαZr1-α cluster significantly enhances the generation of optical electronics and promoted its transfer. The bimetallic MOF photocatalysts provide a new way for efficient photocatalytic collaborative removal of Cr (VI) and TC-HCl pollutants from wastewater.