A Sustainable and Effective Approach to Oil Mist Filtration: Oleophobic Bimodal Structured Filters Based on Acrylic Waste

Oil mist filtration is essential for reducing environmental pollution and extending equipment lifespan. This study explores the fabrication of nano/microfibrous filter mats from acrylic fiber wastes using solution blowing (SB) and centrifugal spinning (CS) techniques, offering a sustainable approach to advanced oil filtration. The effects of neat, oleophobic-coated single-layer, and multilayer structures on filtration performance were analyzed. While SB mats exhibited finer fibers and a denser structure, CS mats had a more porous and fluffy morphology. To enhance oleophobicity, SB mats were coated with a modified perfluoroalkyl silane (mFAS) by spraying. The coating increased the paraffin oil contact angle by 120° but also led to higher pressure drops (ΔP) due to the altered pore structure and surface characteristics. A multilayered design incorporating CS mats as the top layer and mFAS as an intermediated layer created asymmetric wettability and a bimodal structure, achieving over 99% filtration efficiency. The 5S/2.5 M/5C (×2) configuration in the multilayered designs demonstrated superior performance, (filtration efficiency (η) over 99%, lower ΔP, and slower clogging). These results indicate that the acrylic waste-based bimodal structured fibrous mats produced can be used as an effective and sustainable oil mist filtration media.