Biodegradable Membrane with High Porosity and Hollow Structure Obtained via Electrospinning for Oil Spill Clean-up Application

The use of biodegradable polymers for the production of membranes to be used in wastewater treatment has attracted increasing interest considering the possibility of reducing the risk of second pollution. In this work, porous fibrous membranes based on polylactic acid and polyethylene oxide (PEO) blends were prepared. The solutions were electrospun using two approaches: (i) conventional coaxial electrospinning followed by leaching treatment (double-step, DS); (ii) coaxial wet electrospinning with in situ leaching (single-step, SS). By varying PEO type and processing method it was possible to control membranes structure and porosity. DS leaching treatment lead to surface porosity (i.e. shell leaching), while SS allowed obtaining hollow and porous fibers (i.e. with shell and core leaching). Process, properties and structure relationships of devices were analysed trough rheological, morphological, mechanical and surface characterizations. Furthermore, the influence of the different porous structures on oil sorption capacity and reusability of the membranes was evaluated. Results reveal that different porosities lead to a variation in membranes mechanical performance, in their wettability and, consequently, in their oil spill cleanup capacity. Membranes obtained with SS displayed higher performance in oil removal if compared to the DS ones, due to their hollow structure and higher surface area.