Substantial Improvement of Oil Aerosol Filtration Performance Using In-Plane Asymmetric Wettability

Xin Wei; Yufeng Liu; Hua Zhou; Feng Chen; Hongxia Wang; Zhongli Ji; George G Chase; Tong Lin

doi:10.1021/acsami.0c06349

Substantial Improvement of Oil Aerosol Filtration Performance Using In-Plane Asymmetric Wettability

ACS Appl Mater Interfaces. 2020 Jun 24;12(25):28852-28860. doi: 10.1021/acsami.0c06349. Epub 2020 Jun 9.

Authors

Xin Wei¹, Yufeng Liu², Hua Zhou¹, Feng Chen², Hongxia Wang¹, Zhongli Ji², George G Chase³, Tong Lin¹

Affiliations

¹ Institute for Frontier Materials, Deakin University, Geelong, VIC 3216, Australia.
² Beijing Key Laboratory of Process Fluid Filtration and Separation, College of Mechanical and Transportation Engineering, China University of Petroleum, Beijing 102249, PR China.
³ Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States.

PMID: 32463655
DOI: 10.1021/acsami.0c06349

Abstract

Oil aerosol usually causes air pollution, health issues, and corrosion to equipment. The removal of aerosol oil particles from the air is a crucial process in industrial production and daily life. Although fibrous filters have been a widely used material for the separation of oil aerosol from the air, it is still a challenge to separate submicrometer aerosol oil particles with both high filtration efficiency and low resistance. Herein, we report a novel approach to markedly reduce the pressure drop of a fibrous filter and simultaneously increase its aerosol filtration efficiency, only by surface treatment to make the filter have in-plane alternating superoleophilic and superoleophobic patterns. We used a spraying method to prepare superoleophobic and superoleophilic patterns on the filter. The best filtration results were achieved when two layers of the patterned filters that have superoleophobic and superoleophilic strips (both width, 5 mm) were stacked in a way that the opposite wetting surfaces contacted each other between the layers. The filter showed a much-reduced filtration resistance and the pressure drop (4.16 kPa) at the pseudo-steady state being at least 45% lower when compared to the two-layer controls with a homogeneous surface wettability (i.e., untreated surface, superoleophobicity, and superoleophilicity). It also showed higher filtration efficiency (98.37% for small oil mists and 99.99% for large oil mists) and over two times higher quality factor (0.99 kPa^-1 for small oil mists and 2.27 kPa^-1 for large oil mists). The asymmetric wettability leads to the formation of unobstructed channels for the air stream to penetrate through the filter matrix, leading to a low resistance with improved oil capture efficiency. The pattern strip width showed an effect on filtration performance. This unexpected finding may provide a novel approach to designing high-performance, low energy consumption, and long-life coalescence filters.

Keywords: fibers; functional coatings; patterning; porous materials; surface modification.