Biodegradable PLA/PBS open-cell foam fabricated by supercritical CO2 foaming for selective oil-adsorption

Selective oil-adsorbing materials are crucial for the treatment of oil spills and oily wastewater. However, most existing oil-adsorbing materials are traditional petroleum-based polymers that consume non-renewable resources and generate hardly-degradable plastic waste. Moreover, toxic organic solvents are usually used in their preparation process, which also causes environmental pollution. Herein, fully biodegradable poly(lactic acid) (PLA)/poly(butylenes succinate) (PBS) foams with outstanding selective oil-adsorption performance were successfully prepared using the supercritical CO2 foaming technology, a solvent-free process. With PLA as the matrix and PBS as the cell-opener, the resulted PLA/PBS foam shows a highly interconnected lace-like open-cell structure and an open-cell content of 98.2%. Meanwhile, the PLA/PBS open-cell foam possesses an expansion ratio of 43.6 and a porosity of 97.7%, which are about 315% higher than previous research. The PLA/PBS foam can selectively adsorb oil from water to achieve efficient oil–water separation and water purification. The PLA/PBS foam presents an adsorption capacity of 7.9–21.9 g/g for various organic solvents and oils. What’s more, the adsorption capacity for CCl4 shows no obvious attenuation during 20 adsorption–desorption cycles. These benefit from its unique open-cell structure and high porosity. This work provides a new method for the green preparation of eco-friendly high-performance oil-adsorbing materials.