Chelation Assembly of Cellulose Nanohydrogel onto Flower-Like Structured Foam with Underwater Superoleophobicity for Highly Efficient Oil–Water Separation

Currently, with the increasingly serious pollution problem of oily wastewater, it is urgent to develop advanced materials and methods. In this work, a Fe(III)-CMC@Ni(OH) 2 @Ni composite foam with superhydrophilic and underwater superoleophobicity was fabricated by an in situ growth of flower-like Ni(OH) 2 nanoparticles and chelated assembly of Fe(III)-CMC nanohydrogel via a layer-by-layer self assembly using [Formula: see text] ion and carboxymethyl cellulose (CMC). The composite foam could separate various oil/water mixtures and exhibited excellent efficiency over 99%. This foam possessed ultrahigh water flux (220000[Formula: see text]L [Formula: see text] [Formula: see text] and better resistant to penetration pressure (1.3[Formula: see text]kPa). After 30 cycles, the oil–water separation performance reduced only 0.5%, but the foam structure was still stable that guarantees a better lifetime. Besides, this composite foam showed anti-fouling, unique durability and excellent corrosion resistance performance. Taking into account all good properties, Fe(III)-CMC@Ni(OH) 2 @Ni composite foam was expected to be a potential candidate for responding to all kinds of complex oily wastewater conditions.