A　pH-responsive,　charge　switchable　piperazine　derivative,　1,4-bis(3-propane-　sulphonate　sodium)-piperazinediethanesulfonic　acid　disodium-sulfate　(4),　has　been　designed　via　a　stepwise　synthesis　and　proposed　as　a　draw　solute　to　remove　arsenics　(As-III,　As-V)　from　water　through　forward　osmosis　(FO).　Having　multiple　sulfonic　groups,　4　generates　a　high　osmotic　pressure　and　produces　a　water　flux　as　high　as　58.4　LMH　at　a　dilute　concentration　(0.24　M),　surpassing　most　of　the　existing　draw　solutes　in　water　transfer　rate　under　the　similar　experimental　conditions.　Compound　4　at　0.24　M　yields　a　water　flux　of　52.9　LMH　with　a　100%　As-V　rejection,　and　57.8　LMH　with　a　96.0%　As-III　rejection　when　50?ppm　As-V　or　As-III　as　the　corresponding　feed,　manifesting　the　best　performance　in　arsenic　removal　and　concurrent　water　recovery　efficiency.　Remarkably,　being　a　polymeric　configuration　in　water,　4　has　a　negligible　solute　loss　in　the　FO　process.　4　can　be　readily　regenerated　for　reuse　in　FO　by　precipitation　from　its　solution　through　acidification.　The　abundance　in　ionic　groups　and　the　pH-responsive　property　coupled　with　a　supramolecular　configuration　make　4　an　ideal　draw　solute　for　FO　wastewater　treatment.　(C)　2019　Elsevier　Ltd.　All　rights　reserved.