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

A novel hybrid polyimide/graphene oxide membrane (<b>PI/G</b> ₄₀₀, <b>PI/G</b> ₅₀₀, and <b>PI/G</b> ₆₀₀) 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 <b>PI/G</b> revealed high thermal stability values up to 800 °C when compared to the <b>PI</b> 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 <b>PI</b> matrix, the tensile strength values were increased from 13.2 MPa for the <b>PI</b> membrane to 52.11 MPa for the <b>PI/G</b> ₆₀₀ membrane. Moreover, the <b>PI/G</b> ₅₀₀ 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 <b>PI</b> membrane (50.8% and 4.14 L/m² h). Finally, incorporating graphene oxide particles into the <b>PI</b> 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.