Triboelectric nanogenerator (TENG) enhanced air filtering and face masks: Recent advances

Currently, a growing hazard generated by high particulate matter (PMs) concentration in air is having a great impact on human health. Due to continuous population growth and industrial activity the production of pollutants has reached unprecedented levels, urging new technologies for protection against airborne particles. Among different technologies to filter PMs, the use of triboelectric nanogenerators (TENGs) have been proven an useful technology, with potentially-low environmental impact. This technology, based on triboelectrification, ensures effective and high filtration efficiency as well as provides advantages multifunctionality based on TENGs self-powering abilities. The necessity of filtration systems has increased their demand with the outbreak of SARS-CoV-2, where the propagation of the virus was dependent on the absorbance of small droplets containing the virus, which could be avoided with the use of face mask and filtering systems. In this review we summarize the main advances on the use of TENGs for TAFs (triboelectric air filters) and in face mask systems (TFMs, triboelectric face masks), focusing both on results against PMs, bacteria and viruses. Furthermore, the prospects and environmental concerns will be also discussed, alongside the potential challenges which this technology can face in the near future.