Cellulose nanospheres coated polylactic acid nonwoven membranes for recyclable use in oil/water separation

Oily wastewater has always been an environmental issue that we are concerned about and committed to managing. Although the superwetting membranes have been extensively studied and widely used in oil/water separation, the abundant discarded membranes are still headaches due to their non-degradable nature. In this work, all-around green material, as well as superhydrophilic polylactic acid (PLA) nonwoven membrane, is designed by coating cellulose nanospheres (CNCs) with the aid of polydopamine (PDA). Plenty of hydroxyl groups and hierarchical rough structure synergistically contribute to the superhydrophilicity and excellent oil/water separation performance of the resultant CNCs/PDA/PLA nonwoven membrane. Interestingly, the efficiency of oil/water separation can be maintained above 98% after 100 times of repeated use. With the outstanding durability and easy controllability, the CNCs/PDA/PLA nonwoven membrane may provide effective solutions to manage the oily wastewater and secondary pollution of the used membrane itself simultaneously. Graphic abstract