Tetrasulfonatomethyl-n-hexyl calix[4]resorcinarene tetrasodium assisted preparation of ZnFe2O4/ZnO composites with enhanced photodegradation performance for organic contaminants

The limited optical adsorption range and rapid recombination of photoexcited electron-hole pairs have severely hindered the development of ZnO-based photocatalysts . As macromolecular compounds, calixarenes become potential photocatalyst modifiers owing to their special molecular structures. In this work, ZnFe 2 O 4 /ZnO heterojunction photocatalysts which consist of ZnFe 2 O 4 nanoparticles and ZnO nanosheets were fabricated by simple hydrothermal reaction with the introduction of tetrasulfonatomethyl-n-hexyl calix[4]resorcinarene tetrasodium (THCRT 1 ). The synthesized ZnFe 2 O 4 /ZnO nanocomposite possesses a larger specific surface area , broader-spectrum absorption and an electronegative surface due to the addition of THCRT. Furthermore, the successful construction of ZnFe 2 O 4 /ZnO heterojunction leads to low charge transfer resistance and enhanced photocurrent density. Therefore, the THCRT-capped ZnFe 2 O 4 /ZnO composite exhibited superior adsorptive performance and removal efficiency towards Rhodamine B (RhB) and Levofloxacin hydrochloride (LH). The calcined nanocomposite degraded 95.80 % of RhB (10 mg L −1 ) and 97.86 % of LH (20 mg L −1 ) after 120 min under simulated sunlight illumination at a minimal catalyst dosage of 0 .1 g L −1 . Additionally, to determine the band structures , the band gaps, valence band positions and the Fermi levels were measured by Tauc plot, valence band x-ray photoelectron spectroscopy (XPS-Vb) and Mott-Schottky plot, respectively. Finally, based on the band structure results, we proposed a potential photocatalytic mechanism of n-n heterojunction. This work offers a promising prospect in the treatment of sewage containing organic contaminants.