Z-scheme heterojunction of TiO2/NH2-MIL-125(Ti) growing on carbon fibers cloth: Photocatalytic degradation of tetracycline and toxicity analysis

Abstract

Photocatalysis stands out as a promising and eco-friendly method for antibiotics removal, yet traditional photocatalysts , mainly in powder form, are often prone to detachment and loss, making them difficult to recycle and reuse. In this work, we address this challenge by using carbon fiber (CF) cloth with a large area as a carrier for catalysts. To improve the photocatalytic efficiency, we synthesized TiO 2 nanorods on the surfaces of CF cloth and incorporate NH 2 -MIL-125 (Ti) on them, thus the Z-scheme heterojunctions CF/TiO 2 /NH 2 -MIL-125(Ti) was obtained. In order to fully understand the structural properties and performance advantages of CF/TiO 2 /NH₂-MIL-125 (Ti) composites, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray photoelectron spectroscopy (XPS), UV–visible diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), Brunauer-Emmett-Teller (BET), Mott-Schottky (M-S) and valence band X-ray photoelectron spectroscopy (VB-XPS). Due to the special electronic transmission path of the Z-scheme heterojunctions , the CF/TiO 2 /NH 2 -MIL-125(Ti) composite achieve 95.30 % degradation of tetracycline (TC) within 210 min. The composite also shows exceptional reusability, with a degradation rate of 93.55 % maintained even after four cycles. Finally, we proposed a pathway and catalytic process for the decomposition of TC by CF/TiO 2 /NH 2 -MIL-125(Ti) and performed toxicity assessments of TC and its precursors using T.E.S.T. software. This novel photocatalyst composite offers a green and efficient approach for treating antibiotic wastewater, presenting a significant advancement in environmental remediation strategies. • A Z-scheme structured TiO 2 /NH 2 -MIL-125(Ti) grown on large scaled carbon fiber. • The catalyst is easy to recycle and has high stability. • The Z-scheme structure improves the photocatalytic activity. • The pathway and toxicity of intermediates for catalytic process were analyzed.