There is a critical need to develop durable and reusable materials for oil-water separation, especially in harsh environments. Traditional anti-fouling mesh-based separation technologies are not reusable and limited by poor temperature resistance. Here we report a novel superhydrophilic and underwater superoleophobic NiO/Ni mesh which shows superior oil/water separation in harsh environments, with reusable and durable properties that can separate different oil-water mixtures with and without sand and soil contaminants, a >99% separation efficiency and up to 5.4 × 104 L m-2 h-1 permeate flux. The material is able to retain its superior performance over the 20 cycles we measured and for mixtures of sticky oils its performance is easily recoverable after a quick heat treatment. Our separation methodology is solely gravity-driven and consequently is expected to be highly energy-efficient. We anticipate that our separation methodology will have numerous applications, including in the clean-up of oil spills, wastewater treatment and other harsh condition oil-water separations.