Nanoporous Carbon Foam for Water and Air Purification

The design of advanced filter materials to realize worldwide access to clean air and drinking water is of imminent importance. However, complex procedures and toxic raw materials used in the manufacturing process can easily result in secondary pollution, defeating the original purpose. Herein, a green and facile table salt (sodium chloride, NaCl)-assisted pyrolysis strategy is reported to construct nanoporous carbon foam from edible feedstocks (such as agar, pectin, and flour) for use as efficient filter materials. NaCl plays a part in the pore-forming agent and rigid scaffold, which constructs the secondary porous structure while efficiently preventing the self-assembly three-dimensional network structure from thermally collapsing during pyrolysis. Taking advantage of the tailored porous structure, the agar-derived nanoporous carbon foam exhibits a high oil/organic solvent adsorption capacity of up to 202 times its own weight. Besides, an air filtration paper, composed of the obtained material and nonwoven fabric, possesses a PM2.5 filtration efficiency of over 99% with a low-pressure drop of 112 Pa, better than commercial masks. Considering the simple fabrication process and outstanding adsorption/filtration performance, the nanoporous carbon foams fabricated from sustainable precursors have great potential for environment-related applications.