Tolerant chitosan/carboxymethyl cellulose@calcium composite films on nylon fabric for high-flux water/oil separation

Nacre as a natural organic-inorganic composite has outstanding mechanical toughness and oil repellency. Enlightened by nacre, we present here a novel strategy to fabricate superhydrophilic/underwater superoleophobic hybrid films on nylon fabric (NF). The hybrid films were constructed via facile and green layer-by-layer (LbL) assembly of calcium ion (Ca2+), chitosan (CS), and carboxymethyl cellulose (CMC) combined with biomimetic mineralization in CO2 atmosphere. The resulting NF exhibits excellent superoleophobicity underwater, anti-oil-fouling ability, and stability. Under the drive of gravity, the deposited fabric can selectively remove pure and corrosive water from various oil-containing water with preferable separation efficiencies, great water flux (>6903 L·m-2·h-1), favorable oil penetration pressure (1.47 kPa), and outstanding recyclability. Especially, the NF can still sustain high underwater oleophobicity after repeatedly separating oil/corrosive water for 80 times. The green preparation process, eco-friendly and durable coating, and good separation performance allow the as-fabricated NF to be applied in oily wastewater treatment.