Eco-friendly perforated kelp membrane with high strength for efficient oil/water separation in a complex environment

Abstract

• Micro/nano-structured porous membrane is fabricated by laser perforating technology. • The membrane reveals elegant superwetting and excellent mechanical properties. • The membrane shows an excellent permeating performance with high flux and separation efficiency. • The membrane can be easily obtained and degraded naturally. With increasing amounts of the discharge of oily wastewater and the ongoing occurrence of oil spills at sea, it is vitally important to achieve efficient and green oil/water separation using an effective and low-energy-consumption technology. Although hydrogel membranes for oil/water mixtures separation have been extensively reported, it is still a challenge to develop hydrogel membranes with superior mechanical properties and resistance to complex environment. In our work, a perforated kelp membrane (PKM) was fabricated through a one-step laser perforating method using natural kelp as a raw material. The obtained membrane is capable of achieving oil/water separation with high flux (˃1210.7 L·m −2 ·h −1 ) and excellent separation efficiency (˃99.8%). In addition, the kelp membrane manifests favorable mechanical performances with a tensile strength of 2.12–3.89 MPa and strain of 117.59–183.00%, when exposed to complex conditions (strongly acidic, alkaline, saline, low temperature, and boiling water). More importantly, kelp membranes are completely degraded under natural condition after 30 days. Therefore, the economy and eco-friendly PKMs with outstanding mechanical properties are expected to provide a promising candidate for oil/water separation.