Researchers reviewed how agricultural, forestry, and marine waste can be turned into lightweight materials that block electromagnetic interference. The idea is to replace dense metal sheets and costly synthetic carbon nanomaterials with biomass-derived carbon, cellulose fibers, and biopolymers from sources like bamboo, fruit peels, cotton, and shrimp shells. Reported lab results include shielding effectiveness above 100 decibels for silver-coated cotton and 77.5 decibels for carbon foam made from banana leaves. These numbers matter for electronics, wearables, and automotive radar, but the bigger sustainability question is whether the processing steps stay cheap and clean enough to compete at scale. The review notes huge annual waste streams, including 140 billion tonnes of agricultural byproducts and 181.5 billion tonnes of forestry residues. That is a large feedstock base, but turning it into usable shielding still requires pyrolysis, chemical treatments, or metal coatings, so the net environmental gain will depend on the full production chain.
