Reduction in oil mist filtration resistance using novel fibrous filters with bioinspired fibrous membrane

Fibrous filters are critical for the removal of tiny oil mists, which is often essential for industrial process and environmental protection. A high pressure drop of the fibrous filter leads to an increase in energy consumption and a tendency to be damaged for fibrous media. The liquid film adsorbed on the surface of fibrous filters owing to the strong capillarity of fine fibers during the oil mist filtration process is one of the main factors resulting in the high pressure drop. Here, we have for the first time reported that a bioinspired fibrous membrane with periodic spindle-knots composited on the oil mist filters can significantly reduce their pressure drop without compromising with filtration efficiency. Coaxial electrospinning was used to prepare the bioinspired fibrous membrane directly on the commercial glass fiber filters. The pressure drop of the composite filter with the bioinspired fibrous membrane was reduced to 2.64 kPa, decreased by 30% and the quality factors were enhanced by 40% for small oil mists and 60% for large oil mists when compared to the control group. Photocuring technology was used to freeze the liquid distribution in filters during the airflow was on and a cluster-like liquid film was observed, suggesting that the change of liquid film morphology is the reason for the reduction in pressure drop. A “migration-instability-holes forming” mechanism was proposed to explain the cluster-like liquid film formation process. Such a novel concept may provide new ideas for fighting against liquid film resistance and the improvement of low energy consumption filters for various applications.