Increasing air pollution has sparked significant public health concerns due to its wide-ranging and negative consequences on humans. As a result, air filtration technology development has received a lot of attention as a viable and promising alternative. 

Many efforts have been made in the past to enhance air filtration technology to overcome the trade-off between filtration efficiency and pressure drop. Filtration technologies for indoor air purification include fabric-based filters, ultraviolet (UV) light, and ionized air. Most traditional air filtering systems use high-efficiency particulate air (HEPA) filters. 

Newer technologies that can neutralize all indoor air contaminants, such as UV-based disinfection and bi-polar ionization, will become increasingly significant in the indoor air purification sector in the coming years. 

The development of cost-effective and efficient air filtration systems to eradicate all sorts of indoor air contaminants is a pressing industry demand. The industry is always looking for ways to increase air purifiers' cost-effectiveness, maintenance requirements, and neutralizing capability.

This article will provide an introduction to three innovative structure-based strategies in AC filters technology, including component hybridization, fiber morphology modification, and multilayer stacking. 

Structure-Based Innovation Strategies 

Controlling and enhancing structural qualities allows innovative air filters to be designed. Due to its deep influence on filter structure, fiber diameter is a fundamental design feature in air filtering systems. Nanofibers, which have submicron dimensions, are particularly desired because they outperform microfibers in several areas, including filtration efficiency and slide effects. Here are the three structure-based strategies currently in research and development. 

  • Air Filter Systems With Component Hybridization

The use of homogenous components in the construction of filters is regarded as a restricted method of improving filter performance. Filters made entirely of nanofibers, for example, have small pore diameters, high packing densities, and constricted air channels, resulting in significant pressure decreases. 

Filters with microsized fibers, on the other hand, have relatively large holes and loosely packed structures, resulting in lower air resistance but lower filtration effectiveness. As a result, hybrid constructions containing fibers and components of varying sizes or dimensions (i.e. microfibers and nanofibers, microspheres, and nanofibers) could provide a way to balance filtering efficiency and air permeability.

  • Air Filtering Systems With Fiber Morphology Modifications

Many researchers have been encouraged to incorporate nanostructures into fibers because of their benefits. For example, Brownian diffusion is a vital filtering system for nanoparticles and is aided by larger surface areas. Fiber diameter is often reduced to achieve larger specific surface areas. 

Modifying the fiber surface's shape would increase filter performance and is another way to increase surface area. Rough fibers have been demonstrated to lower pressure drop by allowing more trim around the fibers and increasing frictional forces between fibers and particles, which aids in efficient PM collection. Several hybrid constructions with multimodal diameters, dimensions, and other features are currently developing.

  • Air Filtering System With Multilayer Stacking

The filtration efficiency increases as its weight and thickness increase. This is because of the lengthier particle retention time and bigger filter surface area. Extended fiber spinning periods can result in heavier and thicker filter layers in standard filter manufacturing methods by placing more fiber in a given interval.

However, because newly spun fibers obstruct the as-formed air channels, filters made in this manner often have bad structural features, such as overly thick packing and tiny pores. As a result of the frequent clogging of narrow pores by bigger particles, the air filters suffer from substantial pressure decreases and have lower functioning life spans. 

These issues prompted researchers to combine numerous filter layers into one filter unit, enabling desired pore size and packing density while increasing filter weight and thickness, resulting in improved service life and quality.