Thermally Stable, Thin, Ultralight, Reusable, and Flexible Multiwalled Carbon Nanotube Membranes for Removal of Heavy Metals, Polycyclic Aromatic Hydrocarbons, and Particulates from Coal Smoke

Rapid industrialization, haphazardous urbanization, and ruthless burning of fossil fuel have alarmingly impacted human health and the environment. The majority of health issues, such as asthma, cardiovascular disease, and cancer, are primarily associated with polyaromatic hydrocarbons (PAHs), particulate matter (PM), nickel (Ni) and cadmium (Cd) heavy metals, and other contaminants. To address these challenges, the development of an efficient air filtration unit to remove the toxic substances from the smoke is a necessity. The majority of the recently developed air filters are architecturally monotonous and bulky and suffer from a trade-off between removal effectiveness and air permeability. Herein, we have proposed an air filter which is scalable, ultralight (∼0.0034 g), thin (∼50 μm), thermally stable (∼500 °C), hydrophobic (contact angle 138° ± 6°), and porous (porosity of ∼57%) with a pore size of ∼16 nm and has an effective packing density of ∼0.64 g/cm 3 . The self-assembled nanoarchitecture network (nanonetwork) air filter has a relatively lower pressure drop (∼133.3 Pa) and can remove ∼99%, ∼99%, and ∼90% and 50% for PAHs, PM, and Ni and Cd heavy metals, respectively. This research will be highly beneficial for designing and developing high-performance fibrous materials for filtering and separation applications.