Cobweb-inspired DNA-based membranes for multicomponent pollutant-oil-water emulsions separation

Abstract

Superwetting membranes are increasingly being applied in oil-water separation processes, especially for conventional immiscible mixtures, micro-emulsions, and nano-emulsions. However, in practical water purification processes, these mixtures usually contain other contaminated components, such as inorganic salts, nanoparticles, organic compounds, proteins, and bacteria. Herein, we report for the first time a superwetting membrane prepared from deoxyribonucleic acid (DNA)-based nanofibril materials for creating a multicomponent pollutant-oil-water filtration system. The development of such a system is challenging, considering that matter dispersed in the water phase must be separated by extra filtration process in conventional oil-water separations. The DNA-based membranes can be prepared with thicknesses as small as several tens of nanometers and transferred to a stainless steel mesh to form cobweb-inspired fibrous membranes. The resulting membranes can successfully filter nanoscale model molecules due to their cross-linked DNA fibril-based pores, and can separate oil-water emulsions because of their underwater superoleophobic/low-oil-adhesion properties. Thus, multicomponent pollutant-oil-water emulsions can be purified at a relatively low operation pressure, allowing the separation of water and other components with only one ultra-filtration membrane. The findings in the present work provide a completely novel route for addressing real-world oily wastewater or other mixtures with complicated compositions.