Chemical　modification　provides　a　solution　to　the　membrane　fouling　problem　in　oily　water　purification.　However,　complicated　synthesis　processes　and　harsh　reaction　conditions　are　frequently　encountered　with　this　approach.　Here　we　developed　two　bifunctional　zwitterionic　materials,　i.e.,　n-aminoethyl　piperazine　propanesulfonate　(P-SO3-NH2)　and　1,4-bis　(3-aminopropyl)　piperazine　propanesulfonate　(P-2SO3-2NH2),　by　a　clean　method　and　grafted　them　onto　membrane　surface　via　a　fast　single-step　reaction.　These　materials　endow　the　resultant　membrane　a　more　hydrophilic　and　smoother　surface,　significantly　improving　the　water　permeability,　fouling　resistance　and　recyclability　of　membrane　in　forward　osmosis　oily　water　reclamation.　The　water　fluxes　produced　by　the　P-2SO3-2NH2　modified　membrane　are　47%　(from　20.0　to　29.3　LMH)　and　60%　(from　16.0　to　25.6　LMH)　higher　than　those　of　the　unmodified　membrane　when　DI　water　and　an　oily　emulsion　(1500　ppm)　as　the　respective　feeds.　A　higher　water　flux　recovery　is　also　achieved　for　the　P-2SO3-2NH2　modified　membrane　(94%)　than　that　of　the　nascent　membrane　(82%)　after　a　12-h　experiment.　These　promising　findings　coupled　with　a　facile　and　efficient　membrane　modification　approach　provide　inspiration　for　both　membrane　exploration　and　oily　water　treatment.　Copyright　©　2019　American　Chemical　Society.