A Comparative Study on the Photocatalytic Efficiency of ZnO, TiO 2 Nanoparticles and ZnO-TiO 2 Nanocomposites in Degrading Pharmaceutical Pollutants.

chemistry Medicinal and pharmaceutical chemistry Nano- and molecular-scale electronics Nano-biomaterials and bioscience Nanomagnetics Nanomaterials, thin films and nanointerfaces Nanomedicine Nanometrology and nanomechanics Nano-optics Nanopatterning, self-assembly and nanofabrication Nanostructures for energy and sensing applications Natural products chemistry Organo main group chemistry Other nanotechnology (unclassified) Other organic chemistry (unclassified) Photochemistry and photovoltaics Physical organic chemistry Supramolecular chemistry Pharmaceutical drugs are now well established as persistent pollutants in aquatic ecosystems with ecological and human health hazards even at trace levels. Current treatments like biodegradation, adsorption and membrane filtration exhibit poor performance and high expense. Here, this approach provides a sustainable and efficient alternative by employing nanoparticle-based photocatalysts for degrading pharmaceuticals. Photocatalytic activities of ZnO and TiO2 nanoparticles (NPs) purchased commercially, and the ZnO-TiO2 nanocomposite prepared using the chemical precipitation method, were tested for their effectiveness against some chosen pharmaceutical contaminants like oxazolidinone antibiotics (Linezolid), Non-steroidal anti-inflammatory drug (NSAID) (Aspirin), and Paracetamol (Crocin). The prepared composite was studied to determine its structural and morphological characteristics. Experiments were performed under different pH, temperature, reaction time and agitation conditions for achieving optimal degradation efficiency. Reactive oxygen species (ROS) produced during the photocatalytic reaction were confirmed as major agents responsible for the oxidative degradation of the compounds. The process was found to perform best at pH 5, 30°C and 60°C (for Visible light and UV respectively) and 120 RPM and reached up to 75 - 80% degradation in 90 minutes. UV light markedly enhanced photocatalytic performance, particularly for Aspirin and Linezolid, with maximum degradation reaching 84.09% for Aspirin (ZnO) and 81.99% for Linezolid (TiO₂) under optimized conditions. Successful degradation was further validated by FTIR analysis of treated and untreated sample. All three nanomaterials exhibited good photocatalytic activity, with varying effectiveness depending on the compound and experimental conditions. ZnO was superior in some instances: TiO2 or the ZnO-TiO2 composite was superior in others. The results indicate compound-specific optimization. Nanoparticle based photocatalysis offers a green, adaptable approach to degrade pharmaceuticals.

Pharmaceutical Drugs, Photocatalysis, Wastewater Treatment, ZnO-TiO2 Nanoparticles When a peer-reviewed version of this preprint is available, this information will be updated in the information box above. If no peer-reviewed version is available, please cite this preprint using the following information: Kaladagi, M.; Umbrajkar, V.; khater, S.; Zoting, K.; Gholap, H.; Khater, M. Beilstein Arch. 2026, 20263. doi:10.3762/bxiv.2026.3.v1 Citation data can be downloaded as file using the "Download" button or used for copy/paste from the text window below. Citation data in RIS format can be imported by all major citation management software, including EndNote, ProCite, RefWorks, and Zotero. © 2026 Kaladagi et al.; licensee Beilstein-Institut. This is an open access work licensed under the terms of the Beilstein-Institut Open Access License Agreement (https://www.beilstein-archives.org/xiv/terms), which is identical to the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0). The reuse of material under this license requires that the author(s), source and license are credited. Third-party material in this work could be subject to other licenses (typically indicated in the credit line), and in this case, users are required to obtain permission from the license holder to reuse the material.