Particulate matter (PM) pollution poses a significant threat to human health on a global scale. However, current conventional air filtration materials, made from nonbiodegradable petroleum-based components, contribute to resource consumption and waste emissions, and are unable to meet the public's demand for environmental protection and energy conservation. For the first time, we report environmentally friendly biobased biodegradable polybutyrolactam (also known as PA4) electrospun air filters with superior mechanical properties and high interception efficiency. Compared with the commercial particulate filtration efficiency of 95% polypropylene melt-blown nonwoven fabric (PFE95), the successfully prepared green biobased degradable PA4 electrospun microfiber membrane has a lighter texture (80%) with as high as 99.85% for PM 2.5 filtration performance. In addition, the PA4 electrospun microfiber membranes also have very stable outstanding mechanical properties especially on tensile strength (>= 4.25 MPa) and Young's modulus (>= 34.82 MPa) at the same time. The biodegradability of PA4 electrospun microfiber membranes in campus soil was investigated, and the weight loss was approximately 88% within 49 days. This would not only make it a promising candidate for green and pollution-free air filtration but also provide insights into the design and development of composite membranes for multifuntionalities for various applications.

Air pollution is a major environmental and public health issue. Each year, large amounts of particulate matter (PM) and other harmful pollutants are released into the atmosphere. Conventional polymer nanofiber filters lack the functionality to capture ultrafine PM. As a sustainable alternative, this work developed titanium dioxide (TiO2) nanoparticle surface-modified cellulose nanofiber (CNF) aerogels for PM2.5 filtration. CNFs were extracted via mechanical disintegration to diameters below 100 nm. The nanofibers were functionalized with 1.0-2.5 wt% TiO2 nanoparticles using citric acid cross-linking. Cylindrical aerogels were fabricated by freezing and lyophilizing aqueous suspensions. Structural, morphological, thermal, and mechanical properties were characterized. TiO2 modification increased density (11.8-19.7 mg/cm3), specific surface area (287-370 m2/g), and Young's modulus (33.5-125.5 kPa) but decreased porosity (99.6 %-97.7 %), pore size (20.2-15.6 nm) and thermal stability compared to unmodified cellulose aerogels. At 2.5 wt% loading, the optimized aerogels achieved 100 % absorption of 0.1-5 mu m particulates owing to reduced pore size. Despite enhanced filtration capabilities, the modified CNF aerogels retained inherent biodegradability, degrading over 70 % within one month of soil burial. This pioneering research establishes TiO2 functionalized CNF aerogels as promising sustainable alternatives to traditional petroleum-based air filters, representing an innovative approach to creating next-generation nanofiltration materials capable of effectively capturing fine and ultrafine particulate matter pollutants.