Adaptive carbon sponge filters for low-energy decentralized water purification

Global water insecurity increasingly exposes the limitations of centralized water treatment infrastructure, which relies on rigid, sequential unit operations that are poorly suited to decentralized, emergency, and resource-constrained situations. Here, we introduce a scalable carbon sponge (CS) platform that integrates mechanically tunable filtration, chemical adsorption, and electrically-assisted filtration and adsorption within a single adaptive architecture. Derived through facile carbonization of melamine sponge, the base CS features a hierarchical porous framework (specific surface area >700 m²/g) that can be reconfigured in situ via mechanical compression, surface modification, and low-voltage polarization to meet diverse purification needs. In its compressed state, the CS functions as a depth filter with an ultrahigh flux (1.8× 10⁶ L·m^-2·h^-1·bar^-1), achieving complete turbidity removal and >99.9 % bacterial retention. When chemically functionalized, the modified carbon sponge (mCS) serves as a high-capacity adsorbent (268.5 mg/g for diclofenac) for emerging and recalcitrant organic micropollutants, demonstrating stable and substantial organic removal. When electrically charged, the mCS becomes an active flow-through electrode (EmCS) for electrosorption, enabling low-voltage capture of nutrient pollutants and ionic impurities while facilitating electrochemical self-cleaning. By utilizing a single adaptive material platform for filtration, adsorption, and electrosorption functions, this work exemplifies a transition from additive treatment trains toward integrated, adaptive multifunctional systems, providing a versatile solution for resilient, decentralized water purification.