Gradual　ionizing　forward　osmosis　(FO)　membranes　were　synthesized　through　tailoring　modifications　with　alendronate　materials　on　polyamide　thin　film　composite　(TFC)　membrane　surfaces.　The　newly　developed　membranes　have　gradually　ionized　surfaces　and　are　more　hydrophilic　after　introducing　amino,　hydroxyl　and　phosphate　groups　derived　from　the　alendronates.　Significantly　improved　performance　was　achieved　with　the　alendronate-modified　membranes　relative　to　the　unmodified　membrane.　With　DI　water　as　the　feed　and　0.5　M　MgCl2　as　the　draw　solution,　the　novel　membranes　yielded　water　fluxes　35–60%　higher　than　the　nascent　one.　When　MgCl2　(2.0　M)　as　the　draw　solution,　alendronate　tetrasodium　(A-4Na)　modified　membrane　had　a　water　permeation　rate　of　17.3　LMH　under　FO　mode　(feed　solution　faced　the　membrane　active　layer)　in　seawater　desalination,　a　25%　increase　compared　to　that　of　the　pristine　membrane　and　surpasses　many　other　recently-developed　FO　membranes,　remarkably　increasing　water　filtration　efficiency.　©　2018　Elsevier　B.V.