Biodegradable hydro-charging polylactic acid melt-blown nonwovens with efficient PM0.3 removal

Polylactic acid (PLA) melt-blown nonwovens are attractive candidates for existing non-degradable air filtration materials due to their unique balance between durability in use and biodegradability at their end-of-life. However, owing to the charge instability caused by conventional corona electret treatment, the filtration performance of PLA melt-blown nonwovens is insufficient to be utilized in practical applications. Herein, we presented an effective hydro-charging treatment strategy to prepare biodegradable PLA melt-blown nonwovens with efficient PM0.3 removal. In this process, a large amount of unstable charge was generated by friction between pressurized deionized water and PLA melt-blown microfibers under the influence of negative pressure suction. Then, the unstable charge on microfibers was transformed into stable charge by hot air drying. Through the adjustment of water pressure, conveyer belt speed and drying temperature, we optimized the hydro-charging treatment process. The resulting hydro-charging PLA melt-blown nonwovens (HC-PLA) shown improved PM0.3 removal efficiency (94.63%), a lower pressure drop (11.74 Pa) and a reasonable quality factor (0.249 Pa−1). After experiencing a hydro-charging treatment, PLA melt-blown nonwovens appear to carry more stable and plentiful charges, according to the surface potential and thermally stimulated discharge (TSD). In addition, plausible charge generation and stable storage mechanisms were proposed based on the optimal performance, which provide promising benefits for the development of long-term and highly efficient filtration materials.