Harnessing Squid Bone for Ultra‐Permeable Water Purification Membranes

Abstract As emerging contaminants like nanoplastics, organic dyes, and inorganic particles proliferate, traditional water purification faces significant challenges. Here, a novel solution grounded in sustainability and efficiency: ultra‐permeable membranes crafted from carboxylated β‐chitin nanofibers derived from squid bone is introduced. The 124‐nm‐thick membrane exhibits an exceptional pure water flux of 46 207 L·m −2 ·h −1 bar −1 with complete rejection (100%) of 100 nm nanoplastics. The 247‐nm‐thick membrane achieves 100% rejection of 50 nm nanoplastics, whereas the 1.8‐µm‐thick membrane attains 99.2% rejection of 1.5 nm rhodamine B dye. The breakthrough performance is attributed to the nanofibers' ultrafine dimensions (1.2 × 2.2 nm) and enhanced porosity resulting from carboxylate‐mediated electrostatic repulsion. The mathematical models substantiate that this optimized porosity dramatically enhances filtration efficacy. Moreover, life cycle and techno‐economic assessments affirm the approach's sustainability and economic feasibility. By marrying advanced material science with circular economy principles, this squid bone‐derived membrane not only tackles global water purification challenges but also exemplifies how nature‐inspired innovation can lead to scalable, eco‐friendly solutions.