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 Fe[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 m[Formula: see text] h[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.
