Facile fabrication of super-hydrophilic cellulose hydrogel-coated mesh using deep eutectic solvent for efficient gravity-driven oil/water separation

The development of sustainable, low-cost, green and efficient oil-water separation materials is an attractive and challenging work. Oil/water separation process has been achieved by a variety of materials with special wettability, but most materials require complex instruments or involve toxic and corrosive chemicals, which might lead to some potential economic and environmental issues. Our work proposed here is a novel super-hydrophilic, underwater super-oleophobic cellulose hydrogel-coated mesh (CHCM) which produced by deep eutectic solvent, aimed for efficient gravity-driven oil/water separation. Based on this pre-wet CHCM, the separation efficiency of various oil-water mixtures was above 98.0%, and the results also showed that CHCM has good recyclability and durability, even after 20 cycles, the separation efficiency also maintained at 98.5%. Impressively, the prepared CHCM also exhibited good salt resistance; it can separate a high efficiency pump oil mixture from a saturated aqueous NaCl solution. Through XPS analysis of CHCM, the oil-water separation mechanism is due to the large number of super-hydrophilic groups on its surface. This simple, green, and efficient method overcomes an important barrier to the safe separation of oil-water mixtures and provides insights into the design of advanced materials for practical oil-water separation.

Automated summary

The study introduces a novel super-hydrophilic, underwater super-oleophobic cellulose hydrogel-coated mesh produced by deep eutectic solvent, which efficiently separates various oil-water mixtures with good recyclability and salt resistance. XPS analysis revealed that the large number of super-hydrophilic groups on the surface of the material is crucial for the oil-water separation mechanism.