The increasing prevalence of pharmaceutical contaminants, particularly antibiotics, poses significant challenges to water quality and human health. A recent study published on March 15, 2025, investigates the efficient removal of cephalexin, a common antibiotic, using Fe-doped TiO2–Bi2O3 nanocomposites as photocatalysts. This research emphasizes the importance of advanced materials to mitigate the environmental impact of pharmaceuticals.
Cephalexin, renowned for treating various bacterial infections, enters aquatic environments primarily through wastewater discharge from medical facilities, agricultural runoff, and improper disposal. The study highlights the long half-life of antibiotics, which exacerbates the development of antibiotic-resistant bacteria and endangers microbial ecosystems.
The novel photocatalysts were synthesized via the sol-gel method and characterized using techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and diffuse reflectance spectroscopy (DRS). The study determined the optimal composition of the photocatalyst—consisting of 3 wt% iron and 11 wt% bismuth oxide—that displayed significant photocatalytic activity under visible light.
According to the authors, "The optimal conditions for the characteristics of solution pH, cephalexin concentration, and photocatalyst concentration were found to be 9, 5 mg/L, and 1.5 g/L, respectively." These conditions led to approximately 73.4% degradation of cephalexin after 240 minutes under visible light irradiation.
Utilizing response surface methodology, researchers optimized the photocatalytic degradation through systematic modeling of various operational parameters including initial pH, catalyst dosage, and pollutant concentration. The study recorded a marked enhancement in photocatalytic degradation efficiency when exposed to ultraviolet light, achieving nearly 96% degradation at 120 minutes.
Notably, the study also assessed the reusability of the catalyst. "Reusability results showed approximately 4% reduction in cephalexin degradation after five runs," indicating the stability and enduring efficiency of the Fe-doped TiO2–Bi2O3 nanocomposite.
The mechanism behind the photocatalytic activity involves the generation of reactive oxygen species such as hydroxyl radicals, which actively participate in the degradation of organic pollutants. The findings suggest the iron doping enhances the photocatalytic properties by shifting the absorption spectrum from ultraviolet to the more widespread visible spectrum, making the catalyst viable for solar-energy applications.
Overall, this research contributes significantly to the field of environmental remediation by providing insights on effective strategies for antibiotic removal. The synthesized Fe-doped TiO2–Bi2O3 composites hold promise for future applications where efficient and sustainable water treatment solutions are required, addressing pressing environmental issues associated with pharmaceutical residues.
These advances highlight the urgent need for innovative solutions to tackle water contamination and safeguard public health against the rising tide of antibiotic resistance. The deployment of such technologies could play a pivotal role in promoting environmental sustainability and ensuring the safety of drinking water.