Assessing the Stability and Photocatalytic Efficiency of a Biodegradable PLA-TiO2 Membrane for Air Purification

Abstract

The potential of a biodegradable polylactic acid (PLA)-TiO₂ membrane for air purification is investigated, utilizing the environmentally friendly solvent Cyrene. Through the integration of TiO₂ nanoparticles within a PLA matrix, the membrane is used to degrade ethanol as a model volatile organic compound (VOC) under UV light. Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX), and UV–vis spectrophotometry confirm the porous structure of the membrane, the even distribution of TiO_2, and its effective band gap of 3.06 eV, respectively. Ethanol adsorption is best described by the Langmuir isotherm model, suggesting monolayer coverage on a homogeneous surface. Photocatalytic tests demonstrate that the membrane decomposes ethanol (6800 ppm) within 14 min under UV light, generating acetaldehyde, acetic acid, formaldehyde, and formic acid as intermediates, and ultimately producing CO₂ and water. Reusability tests indicate a decrease in decomposition time over successive cycles due to increased TiO₂ exposure from the gradual degradation of PLA. However, this degradation poses challenges for continuous use, compromising the membrane's long-term durability.