Rational designed ZIF-8@PDA@PDMS composite sponge for efficient and sustainable particulate matter filtering under harsh environment

Particulate matter (PM) is a significant danger to both environment and human health. Despite the development of a series of air filters, they do not work well in harsh environment such as high temperature, high humidity or long-time filtration. To make a three-dimensional (3D) particle capture device, a sacrificial template approach was used to manufacture polydimethylsiloxane (PDMS) sponge, and then zeolite imidazole framework-8 (ZIF-8) was grown in situ on the 3D network of PDMS sponge. The removal efficiency of PM 2.5 or PM 10 is greater than 99.8% because of the high specific surface area and porous network structure of PDMS sponge, as well as the large number of metal sites of ZIF-8. In addition, the sponge filter has long-term filtration stability and still achieves excellent performance after 65 h of filtration. The composite sponge can adapt to harsh environments such as high temperature (250 °C) and high humidity (90% RH). Composite sponge filter has a regular shape, and it may be customized to any shape as required. This study provides a new idea for designing 3D high-efficiency air filters that can adapt to harsh environments.