Water hyacinths stem from Lake Tana, the largest Lake in Ethiopia, creating an economic impact by affecting biodiversity and agricultural activities. The Lake has been critically infected by the weed, and aquatic biodiversity has been put at extreme risk. Consequently, it is very essential to devise a mechanism to convert the weed into a valuable product such as a dense graphene oxide membrane (GOM). GO is made up of a single layer of sp 2 hyb ridized carbon lattice and surface functional groups that contain oxygen. This thesis aims to synthesize a graphene oxide-dense membrane from a water hyacinth stem obtained from Lake Tana to treat saline water. The water hyacinth stem is pyrolyzed from (400 to 540 ) o C, for (1- 3)hrs. to synthesize graphite. H2SO4, H3PO4, KMnO4, and H2O2 are used to produce graphene oxide from graphite by using the Improved Hummers’ method. GO was characterized by FT-IR spectroscopy, SEM, TGA, and XRD techniques. Graphene oxide membrane (GOM) was synthesized by phase inversion and sintering method from GO powder and polyether sulfone (PESf) as a binder. The RSM in conjunction with the face-centered central composite design (FCCD) was used to optimize the process parameters. The proximate analysis of the water hyacinth stem results in moisture content of 5.5± 1.32%, volatile matter, 66 ± 2.64%, ash content of 18.7 ± 2.12%, and fixed carbon of 9.8 ± 2.88% on a dry basis. The chemical composition of water hyacinth stem is cellulose 39.437 ± 1.37%, hemicellulose 40 ± 2.64%, and lignin, 20.563 ± 1.34% from extractivefree WHS. The FTIR results show that GO has different functional groups like hydroxyl, epoxy, carboxylic acid, and carbonyl. The thermal stability analysis of GO shows that mo isture evaporates below 200 ℃, different oxygen-containing functional group breakdown between 200 ℃ and 450 ℃, and from 450 ℃ to 900 ℃ the carbon skeleton is sublimated. The membrane synthesized from GO, with a thickness of 165 µm has high salt (NaCl) rejection performance (93.5 %) and the synthetic saline water flux through the membrane is 249.68 L/m 2 hr. Therefore, the resulting membrane was a nanofiltration membrane with high desalination efficiency of monovalent salts and high water throughput. Keywords: Graphene oxide, Improved Hummers ’method, self-healing, water hyacinth stem