Facile synthesis of Ni-based layered double hydroxides with superior photocatalytic performance for tetracycline antibiotic degradation

The purpose of this study was to investigate the photocatalytic performance of Ni-based layered double hydroxides (LDHs) in degradation of tetracycline (TC) as a model antibiotic pollutant. Two kinds of Ni-based LDHs (NiFe-LDH and NiCr-LDH) with chloride and carbonate ions in the interlayer region were facile fabricated by chemical co-precipitation method at room temperature and characterized using Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy disperse spectroscopy (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) techniques. The results showed that the asprepared LDHs materials performed superior photocatalytic efficiency to eliminate TC from aqueous water solution under UV-vis light irradiation. The photocatalytic efficiency depends on the catalyst dosage and TC concentration. Furthermore, the plausible photocatalytic degradation mechanism was proposed by means of radical trapping and electron spin resonance (ESR) tests. It is found that the photocatalytic degradation of TC by Ni-based LDHs follows an oxygen-induced pathway, and the superoxide radical (center dot O-2(-)) and hydroxyl radical (center dot OH) play a major role in the photocatalytic degradation process. The study provided a valuable insight into fabricating high-performance and environmentally friendly LDHs for removal of antibiotics in waste water.