An acid–alkali–salt resistant cellulose membrane by rapidly depositing polydopamine and assembling BaSO₄ nanosheets for oil/water separation

With the increase of oil spills, leakage of chemical products and discharge of oily wastewater, oil–water separation has become an urgent problem. In this study, polydopamine (PDA) was first coated on the surface of paper fibers (PF@PDA) by CuSO₄/H₂O₂ triggering to accelerate the reaction rate. Then, the BaSO₄ nanosheets were deposited on the surface of PF@PDA membrane by alternating soaking process (ASP) to obtain superhydrophilic/underwater superoleophobic membrane (PF@PDA/BaSO₄) for oil/water separation. PF@PDA/BaSO₄ shows good separation efficiency (more than 99%) and high flux (more than 550 L m⁻² h⁻¹) for various oil–water mixtures. Importantly, the membrane shows excellent acid, alkali and salt resistance that maintains the high separation performance even under acid, base and salt solution environments. Moreover, the PF@PDA/BaSO₄ membrane has excellent antifouling property and outstanding reusability. Our PF@PDA/BaSO₄ with low cost, easy preparation and high performance has a good application prospect for oil/water separation even in harsh environments.