Abstract
Electrospun nanofiber, showing large specific area and high porosity, has attracted much attention across various fields, especially in the field of air filtration. The small diameter contributes to the construction of filters with high-filtration efficiency for fine particulate matter (PM), however, along with an increase in air resistance. Herein, composited nanofiber aerogels (NAs), a truly three-dimensional (3D) derivative of the densely compacted electrospun mat, were constructed with the blocks of polytetrafluoroethylene–polyamideimide (PTFE–PAI) composite nanofiber and polyimide (PI) nanofiber. PI/PTFE–PAI NAs with hierarchically porous architecture and excellent mechanical properties have been obtained by thermally induced crosslink bonding. Results indicated that sintering at 400 °C for 30 min could complete the decomposition of polyethylene (PEO) and imidization of polyamic acid (PAA) into PI, as well as generate sufficient mechanical bonding between adjacent nanofibers in the NAs without extra additive. The well-prepared PI/PTFE–PAI NAs could withstand high temperature up to 500 °C. In addition, the filtration tests illustrated that the composite NAs had an excellent performance in PM filtration. More importantly, the filtration behavior could be adjusted to meet the requirements of various applications. The excellent thermal stability and high-filtration efficiency indicated its great potential in the field of high-temperature air filtration.
Highlights
Fibrous filters have the features of good filtration performance and a wide application range, and can effectively filter and remove fine particulate matter (PM) in the air, becoming the most important filtration technology to deal with air pollution
We put forward a novel strategy to prepare a high performance filter for high temperature flue gas filtration
To achieve the excellent performance of the composite nanofiber aerogels (NAs) filter, three high performance polymers (PI, PTFE, PAI) were selected as the building blocks, which were constructed into high-fluffy PI/PTFE–PAI NAs by combining electrospinning and a deconstruction-reconstruction technique
Summary
Fibrous filters have the features of good filtration performance and a wide application range, and can effectively filter and remove fine particulate matter (PM) in the air, becoming the most important filtration technology to deal with air pollution. Filtration efficiency and pressure drop are the two key indicators to evaluate the performance of filter media. Research has developed from various perspectives, e.g., considering single-fiber and fiber-accumulation structures, to solve the low physical interception efficiency existing in micro-fiber air filters. Nanofibers, with small diameters, high porosity, and high specific area, can be utilized to construct nanofibrous filters. Benefiting from the uniformity in fiber diameter, adjustable pore channels and stacked structures, nanofibrous filters have effectively captured PM in the air [1]. Severe problems still remain in the filter consisting of layered up nanofiber meshes, such as high air resistance, high energy consumption, poor mechanical properties, and easy peeling between layers [2,3,4,5]. Difficulties still exist in the preparation of ideal filter with electrospun nanofibers
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