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pubs.acs.org/journal/ascecg
Research Article
Moldable and Plastic-Free Nonwoven Aerosolized Particulate Filters Made from Oil Palm Empty Fruit Bunch and Hairy Cellulose Fibers Dharu Feby Smaradhana, Joanne Li, and Koon-Yang Lee *
Cite This: ACS Sustainable Chem. Eng. 2025, 13, 6209−6221
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ABSTRACT: Addressing the environmental impact of conven- tional air filters made from fossil-derived polymers is critical for advancing sustainable air filtration materials. This study presents plastic-free nonwoven air filters produced from oil palm empty fruit bunch (EFB) fibers using (hairy) cellulose fibers as binders through a manufacturing process akin to papermaking. Refining the cellulose fibers introduces ″ hairy ″ microfibrils and fines, which enhance the structure and performance of the nonwovens. With only 10 wt % hairy cellulose pulp refined for 30 min, the EFB/hairy cellulose fiber nonwoven achieves a filtration efficiency of ∼ 98%for PM 1 and a high quality factor of ∼ 36 kPa − 1 , demonstrating excellent filtration performance with low pressure drop. These nonwovens also exhibit exceptional formability, allowing direct
molding from the never-dried state or remolding via steam rewetting with minimal loss in filtration efficiency (less than 1.5%pt). Lifecycle assessment (LCA) results indicate that the production of EFB/hairy cellulose fiber nonwovens has significantly lower impacts in global warming potential and all end point categories (human health, ecosystem quality, and resource scarcity) compared to polyester-based air filters. Our work paves the way for upcycling oil palm waste into high-value air filtration materials, reducing the reliance on fossil-derived air filters. KEYWORDS: agricultural waste, waste valorization, sustainable materials, biobased fibers, sustainable air filtration, green composites, LCA
particles effectively while maintaining a high airflow. 10 Nonwoven air filters are particularly valued for their ease of manufacturing and random fiber arrangement, which creates complex pathways for particles to be captured efficiently while retaining low airflow resistance. 11 However, most air filters are made from fossil-derived synthetic polymers, such as polypropylene, polyester, and polyamide. 12 While these materials are durable and effective for filtration applications, they pose a significant environmental challenge due to their limited recyclability. Even worse, air filters are typically designed for single use, contributing to the growing plastic waste problem. In response to the environmental burden posed by fossil- derived synthetic air filters, various research effort has been poured into developing nonwoven air filters from natural fibers due to their renewability and biodegradability. 13,14 Various
1. INTRODUCTION Air pollution poses a significant threat to both the environment and human health (HH), raising global concern. 1 Among the various pollutants, particulate matter (PM) is particularly harmful. 2 PM consists of tiny particles and droplets suspended in the air, which include inorganic substances such as silicates, sulfates, and nitrates, as well as organic compounds such as elemental carbon. 3 PM is typically classified by its size, i.e., PM 10 for PM less than 10 μ m in effective diameter, PM 2.5 for less than 2.5 μ m in effective diameter, and ultrafine particles (typically less than 0.1 μ m in effective diameter). 4,5 PM 2.5 is especially concerning due to its abundance in polluted air as it typically stems from vehicle emissions, industrial activities, biomass burning, and wildfires. 6 It also has the ability to bypass the body’s defenses to reach the lungs and to enter the bloodstream. 7 The prolonged exposure to PM 2.5 is linked to severe health problems, including respiratory infections, cardiovascular diseases, lung cancer, and an estimated 4 million premature deaths annually worldwide. 8,9 To mitigate the health risks stemming from PM, the use of air filtration technology in our daily lives is essential. Air filters are widely used in heating, ventilation, and air conditioning (HVAC) systems, industrial settings, and personal masks to trap
Received: January 2, 2025 Revised: April 14, 2025 Accepted: April 15, 2025 Published: April 23, 2025
© 2025 The Authors. Published by American Chemical Society
https://doi.org/10.1021/acssuschemeng.5c00041 ACS Sustainable Chem. Eng. 2025, 13, 6209 − 6221
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