Contact Lenses–TiO₂ Nanocomposites for a Sustainable Wastewater Remediation

Rising plastic waste from products such as contact lenses underscores the need for innovative recycling solutions. This study presents a sustainable approach to produce reusable photocatalytic hybrid nanocomposites for water treatment through the use of waste contact lenses. TiO2 nanoparticles were uniformly integrated into postused contact lenses via a controlled spray deposition technique, resulting in nanocomposites with different spray times (10, 15, or 20 min). The innovative polymeric hybrids were comprehensively characterized from a morphological, structural, and chemical standpoint using techniques such as scanning and transmission electron microscopy, thermogravimetric analysis, X-ray diffraction analysis, Raman spectroscopy, Z-potential analysis, UV–vis spectroscopy, and Fourier transform infrared spectroscopy. The UV-photocatalytic performance of the resulting systems was successfully tested on two common pollutants: methylene blue (a cationic dye) and sodium dodecyl sulfate (an anionic surfactant). The highest efficiency was obtained through the 20 min spray-coated lenses, able to degrade ∼100% of MB and ∼60% of SDS within 3 h of UV-light irradiation. The difference in the photocatalytic efficiency was attributed to the electrostatic interaction between the individual pollutant and the material’s surface. In addition, the antibacterial activity was assessed on Escherichia coli, a well-known indicator of water fecal contamination. This research paves the way for recycling plastic waste through an affordable and cost-effective production method that aligns with the circular economy principles.