Towards Sustainable and Multifunctional Air-Filters: A Review on Biopolymer-Based Filtration Materials

Air-filtration has played an increasingly important role in keeping desired indoor air quality in spite of the heavily polluted air that has worsened by human being's activities. Because the compositions of the pollutants present in the air are so complex and uncontrollable, traditional air-filtering materials produced from non-degradable plastics or glass fibers are facing a big challenge of effectively removing not only the particulate pollutants, such as PM2.5, but also gaseous pollutants, including toxic chemicals, and bacteria and so forth. These materials are also non-degradable and end up in landfills. As a result, development of new multi-functional filtering materials to satisfy the fast-growing community of air-filtration is currently in a critical need. Natural materials that are well known for their richness in functional groups and suitability for many applications represent a promising material solution for high-performance air-filtration. In addition, these materials are sustainable, and their inherent bio-degradability makes them a green solution. In this review, we summarize the significant studies on using polymeric materials for air-filtration with an emphasis on natural biomaterials. In specific, the characteristics of polluted air, the air filter types and filtering materials are briefly summarized. The advantages of developing green air filters from natural polymers as well as the challenges are highlighted.