Facile construction of novel BiOBr/black-TiO2/tourmaline composites for the synergistic degradation of tetracycline in aqueous

Since antibiotic abuse has posed a long-term threat to the ecological environment and human health, it is urgently needed to explore efficient techniques for the rapid removal of remaining antibiotics in wastewater. In this work, combined solvothermal and hydrothermal methods were reported to synthesize novel BiOBr/black-TiO₂/schorl (BTS) ternary composites to achieve the deep elimination of tetracycline (TC) through the adsorption-photodegradation synergistic effect. A series of characterizations were conducted to investigate the structure, composition, and photoelectric properties of BTS. The results show that compared with pristine BiOBr, black-TiO₂ and the counterpart binary composites, BTS exhibited superior adsorption and photodegradation performance towards TC. Among all the samples, BTS-2 demonstrated the optimal TC removal efficiency of 97.7 % with a dosage of 0.6 g/L under visible light irradiation. Based on the electron spin resonance (ESR) experiments, the possible active free radicals are determined during the photodegradation process. A liquid chromatograph mass spectrometer (LC-MS) test was carried out to identify the intermediates of TC degradation and the plausible degradation pathways were proposed. The excellent TC removal performance over the BTS composite can be attributed to the adsorption-photodegradation properties of the sample and the full utilization of the characteristic of each component within the ternary composite.