Highly Effectual Photocatalytic Remediation of Tetracycline under the Broad Spectrum of Sunlight by Novel BiVO4/Sb2S3 Nanocomposite

Heterojunction photocatalysts (PC) with controllable compositions and in-built electric fields have attracted extensive research interest for their use in the remediation of environmental pollutants, owing to their supreme photocatalytic activity. Here, a simple hydrothermal route synthesizing different mole ratios of BiVO4/Sb2S3 is reported as the PC. The inclusion of Sb2S3 with BiVO4 in the BiVO4/Sb2S3 composite possesses the ability to harvest a wide spectrum of solar light, an increased surface area, and an effective charge separation of the charge carriers. The efficacy of the synthesized catalyst was gauged by the photocatalytic abatement of a recalcitrant pollutant, tetracycline. The highest decomposition efficacy of 88.7% (rate constant 0.01557 min(-1)) was achieved with 0.3 g/L of 1:3 BiVO4:Sb2S3 photocatalyst for the tetracycline under sunlight illumination for 120 min. The catalyst was found stable for up to five cycles with a significant retention of its efficacy. The post-degradation characterizations revealed that the photocatalyst is stable due to the intactness of its crystalline planes, morphology, and surface area. Further, gas chromatography-mass spectrometry (GC-MS) was performed to study the decomposed products formed by the abatement of tetracycline. Moreover, chemical oxygen demand/ total organic carbon (COD/TOC) removals of 80.9% and 85.4%, respectively, were observed for the tetracycline standards, while for real TC pills, it was found to be 78.3% and 82.1%, respectively. This signifies that the photocatalyst has good surface catalytic properties in comparison to the existing expensive and time-consuming physicochemical approaches used in industry.

Automated summary

This study developed a hydrothermal method to synthesize BiVO4/Sb2S3 photocatalyst with different mole ratios, which showed enhanced solar light utilization, increased surface area, and effective charge separation. The optimum 1:3 BiVO4:Sb2S3 photocatalyst exhibited the highest degradation efficiency of 88.7% for tetracycline under sunlight illumination. The catalyst also demonstrated good stability and retained its efficacy after multiple cycles.