Adsorption–photocatalytical remediation for series of tetracycline contaminants with BiOCl–CdS composite under simulated sunlight

Tetracycline antibiotics (TCs) are widely released into the aqueous environments and thus pose much serious threats to aquatic ecosystem and human healthy. Due to their heteroaromatic stable frame structure, the removal of TCs has always been an arduous task. In this investigation, we have successfully prepared a series of BiOCl–CdS composites which were used to well remedy the TCs pollutions. BiOCl presented 3D hierarchical microspheres and CdS nanoparticles were uniformly dispersed on its leave surface, confirming by the characterization of XRD, XPS, TEM, SEM and EDS techniques. Compared with pure BiOCl and CdS, the BiOCl–CdS composite exhibits highly adsorption–photocatalytic degradation toward the removal of TCs under solar light illuminating, reaching up to 91.2% for TC, 83.7% for OTC, 75.1% for CTC, within 60 min, respectively. Based on the UV diffuse spectrum, photoelectrochemical measurements, band potential calculation, LC-MS testing, the active species trapping, a novel adsorption–photocatalytic mechanism is proposed. BiOCl, with 3D hierarchical microspheres, possesses not only excellent adsorption towards TCs through a chelation but also good photo-oxidative ability due to the very positive band potential. When compositing with CdS nanoparticles, the matched band structure could not only expand the solar spectrum harvest but also boost the separation of photogenerated electrons and holes, enhancing the solar light driven photocatalytic activity. In summary, the designed material could be potential commercial application to remedy antibiotic residues from the domestic waste water or industrial discharge driven by solar lighting, with a low cost, easy manipulation, and high efficiency.