High-Performance Polyimide Membranes Containing Graphene Oxide for Reverse Osmosis Desalination

A novel hybrid polyimide/graphene oxide membrane (PI/G₄₀₀, PI/G₅₀₀, and PI/G₆₀₀) was prepared via a blending process, and their performance as reverse osmosis membranes was investigated. The preparation of the hybrid membranes was characterized by using FT-IR, SEM, TGA, mechanical properties, and water contact angle instruments. So, the prepared hybrid membranes PI/G revealed high thermal stability values up to 800 °C when compared to the PI membrane. Also, it exhibited a lower contact angle at 65.4 ± 1.5° for the PI/G400 than the pure PI membrane at 72.4 ± 3.62°, which was explained by the occurrence of graphene oxide material. Additionally, when the graphene oxide particle was added to the PI matrix, the tensile strength values were increased from 13.2 MPa for the PI membrane to 52.11 MPa for the PI/G₆₀₀ membrane. Moreover, the PI/G₅₀₀ membrane exhibited a salt rejection rate of 90% and water permeability of 23.17 (L/m² h) at a pressure of 10 bar, which are considered excellent values when compared to the PI membrane (50.8% and 4.14 L/m² h). Finally, incorporating graphene oxide particles into the PI matrix enhanced water permeability by providing an alternative path for the water molecules and overcoming the trade-off impact of lower membrane rejection with an increased salt concentration.