All-cellulose composite membranes for oil microdroplet collection

Oil spills on ocean waters represent a major threat to marine ecosystems. A significant part of the spilled oil is dispersed in microdroplets that are not recovered by traditional oil-removing methods. In this work, we report on the manufacture of cellulose acetate (CA) electrospun non-woven membranes, stamped with different cellulose nanocrystal (CNC) patterns. We demonstrate the use of the membranes produced as selective oil microdroplets removal from water emulsions with an efficiency up to 80%. Screenprinting was used to imprint different CNC designs on the CA surface membranes. To promote the adhesion between the CNCs and the CNCs with the CA fibers the membrane was subjected to a thermal and chemical treatments. Oil droplets were collected under water in the oleophilic CNC pattern while the water could flow through the hydrophilic CA electrospun non-woven membrane. The application of a non-woven all cellulosic composite membrane for separation of a water/oil suspension is presented. The under-water wetting behavior, of annealed cellulose nanocrystals, for oil is studied. Special consideration is given to the capability for the collection of oil micro droplets in aqueous suspension and the influence of the geometrical pattern of the cellulose nanoparticles layer in oil recovery efficiency.