It　is　challenging　to　purify　wastewater　containing　heavy　metals　at　low　concentrations.　Forward　osmosis　(FO)　is　promising　to　remove　most　of　contaminants　from　wastewater.　However,　the　lack　of　suitable　membranes　disables　FO　to　achieve　its　full　potential.　Here　we　designed　positively　charged　PA-Fe-H2O　and　PA-Fe-Bet　membranes　for　efficient　chromium　(CrO42-)　removal　through　micellar-enhanced　FO　(MEFO)　separation.　These　membranes　were　developed　by　functionalizing　the　ready-made　polyamine　(PA)　membrane　via　eco-friendly　complexation　between　Fe3+　and　carboxyl　groups　of　the　PA　layer　and/or　betaine　(Bet).　A　Fe3+-bridged　hydration　or　quaternary　ammonium　layer　was　formed　which　imbued　the　membrane　with　desirable　properties　for　FO　separation.　The　water　permeability　of　the　PA-Fe-H2O　and　PA-Fe-Bet　membranes　was　increased　by　92%　and　142%,　respectively,　compared　to　that　of　the　PA　membrane　when　0.5　M　MgCl2　as　the　draw　solution.　The　PA-Fe-Bet　membrane　greatly　improved　CrO42-　removal　efficiency　by　increasing　the　water　flux　from　6.2　to　12.0　LMH　along　with　complete　CrO42-　retention　in　the　cetylpyridinium　chloride　(CPC)　facilitated　MEFO　process.　Moreover,　this　membrane　exhibited　enhanced　antifouling　properties　when　exposed　to　CPC　solutions.　The　environmentally　benign　synthesis　approach,　high　CrO42-　removal　efficiency　and　fouling　resistance　of　the　PA-Fe-Bet　membrane　demonstrate　its　potential　for　contaminants　removal.　©　2021　Elsevier　B.V.