Investigating the challenges from background contaminants on Photocatalytic Degradation of Ceftazidime

Photocatalytic oxidation is a well-established and promising technique for degrading organic contaminants into harmless end products. While antibiotic degradation using photocatalysis has been widely studied, much of the research typically focuses on contaminant degradation in isolated conditions. This study investigates the efficiency of a photocatalyst to degrade an antibiotic in the presence of a real-world contaminant background. Specifically, the performance of a semiconductor-composite, Bismuth Titanate-TiO2 coated onto recycled glass chips was studied - for the degradation of ceftazidime (CFZD), a commonly used antibiotic. To evaluate the photocatalyst's effectiveness, CFZD degradation was tested in deionised water, a humic acid solution, and a real-world hospital wastewater matrix. Quantification before and after treatment was performed using UV-Vis Spectroscopy, High-Performance Liquid Chromatography (HPLC), Mass Spectrometry, and Chemical Oxygen Demand analysis. Based on HPLC results, the photocatalyst was able to degrade CFZD by up to 87% within 2 hours, with the degradation efficiency dropping to 82% in the presence of humic acid. Of all the quantification methods, HPLC provided the most accurate results, as expected; however, quantifying CFZD degradation in the hospital wastewater matrix was challenging even by HPLC due to interference from other contaminants and high pollutant loads. This is the first study to demonstrate the removal of CFZD, a key antibiotic, using a bismuth titanate photocatalyst immobilised on recycled glass chips, while also highlighting the challenges of quantifying pharmaceuticals in matrices with dissolved organic matter using different analytical methods. The study discusses the results, future development trends, challenges, and offers a prospective outlook.