Construct a stable super-hydrophobic surface through acetonitrile extracted lignin and nano-silica and its application in oil-water separation

Abstract

It remains a great challenge for the simple, environmentally friendly and low-cost production of oil/water separation membrane. Under this backdrop, a highly efficient membrane based on filter paper, acetonitrile extracting lignin and silica is reported. Two impregnation steps are involved for the membrane preparation, firstly, a thin layer of lignin is coated on the surface of the filter paper and then, silica nanoparticles are adhered to the pre-coated filter paper, leading to the formation of a micro-nano binary structure, which turns the hydrophilicity nature of the filter paper into lipophilicity and strong hydrophobicity. The modified filter paper has a contact angle of 168°, which is 118° higher than that of a reference membrane prepared by technical lignin and silica nanoparticles. The modified filter paper exhibits an excellent separation efficiency as high as 98.6% in the process of oil/water separation. Notably, considering the applied low-cost substrates and the simple dipping operation, this modification route is expected to be easily extended to a versatile of other substrates that need to be hydrophobized.