Photocatalytic degradation of diclofenac using TiO₂-coated 3D-printed PLA

Abstract

The continues presence of pharmaceuticals in aquatic environments is a serious concern due to their persistence and adverse ecological effects. Among them, Diclofenac (DCF), a widely used non-steroidal anti-inflammatory drug (NSAID), is frequently detected at concentrations above safe thresholds in surface water and treated wastewater. Conventional wastewater treatment plants (WWTPs) are ineffective in removing DCF, highlighting the need for advanced technologies. This study investigates the photocatalytic degradation of DCF using a 3D-printed polylactic acid (PLA) structure coated with TiO₂ under UV-A irradiation. The aim of this study is to overcome the limitations of using TiO₂ in powder form in slurry systems and eliminate the need for nanoparticle recovery by immobilizing them on a 3D-printed PLA reactor. Surface treatment with acetone increased the porosity and roughness of the PLA and enhanced the adhesion of nanoparticles. The TiO₂ loading and photocatalytic efficiency was evaluated and reusability test showed the objects are practically reliable for several consecutive runs. A single dip with surface treatment selected as the optimized coating strategy and ICP analysis confirmed successful TiO₂ immobilization with minimal leaching of nanoparticles. Control experiments validated that TiO₂ acts as an active photocatalyst, and the effect of key parameters of the photocatalytic reaction, including time, pH, and initial DCF concentration and catalyst dose, was investigated. Increasing the surface area by changing the structure from mesh to lattice had a significant impact on the possibility of higher catalyst loading and shortening the reaction time. These findings indicate that TiO₂ coated 3D-printed filters are a sustainable and promising solution for removing pharmaceutical contaminants from wastewater, and their potential use in municipal WWTPs and landfill effluents is promising.