We　have　designed　a　novel　type　of　thin-film　nanocomposite　(TFN)　membranes　with　embedded　polyelectrolyte　nanoparticles　(PNPs)　and　investigated　their　applicability　in　the　separation　of　amino　acids.　PNP　particles　were　mixed　with　piperazine　(PIP)　and　interfacial　polymerized　with　trimesoyl　chloride　(TMC),　allowing　for　simultaneous　improvement　in　water　permeability,　amino　acid　selectivity,　and　antifouling　property.　Separation　performance　could　be　conveniently　tuned　by　modulating　the　chemical　structure　of　PNPs　and　their　content　in　TFN　membranes,　as　well　as　adjusting　the　feed　pH　value.　This　work　would　promote　the　application　of　polyelectrolyte　nanoparticles　based　TFN　membranes　in　the　separation　and　purification　of　amino　acids.　(C)　2018　The　Korean　Society　of　Industrial　and　Engineering　Chemistry.　Published　by　Elsevier　B.V.　All　rights　reserved.