Stable and reusable electrospun bio-composite fibrous membranes based on PLA and natural fillers for air filtration applications

Today, air pollution due to fine dust is one of the most critical environmental challenges. To mitigate the potential further environmental impact of air filtration devices, it is essential to explore the use of biodegradable polymers combined with natural fillers, preferably sourced from waste materials, to develop stable, reusable and UV-resistant air filters suitable for outdoor applications. In this work, composite fibrous membranes based on polylactic acid (PLA) and natural fillers were prepared via electrospinning and tested for air filtration applications. Air filtration performances were evaluated at different flow rates, temperature and humidity condition, aiming to simulate outdoor conditions. The addition of 10 wt% of Opuntia Ficus Indica (OFI), Posidonia Oceanica Leaves (POL) or lignin (LIG) particles to PLA solution led to a decrease in fibers diameter increasing membranes filtration performances. PLA/OFI, PLA/POL and PLA/LIG composite membranes exhibited filtration efficiencies of 97.2 %, 99.4 %, 99.6 % for PM3 at a flow rate of 32 L/min, and pressure drops of 114, 103, 105 Pa, respectively. The membranes demonstrated stability maintaining good filtration efficiency across different environmental conditions and after multiple reuse cycles. The addition of OFI and LIG powders also provided effective UV resistance, crucial for ensuring the longevity and performance of air filters exposed to outdoor conditions. These findings underscore the potential of these biodegradable composite membranes for sustainable indoor and outdoor air filtration solutions.