tLiquid-core capsules with a non-crosslinked alginate fluidic core surrounded by a gellan membrane wereproduced in a single step to investigate their ability to adsorb heavy metal cations. The liquid-coregellan–alginate capsules, produced by dropping alginate solution with magnesium cations into gellansolution, were extremely efficient at adsorbing lead cations (267 mg Pb2+/g dry alginate) at 25◦C andpH 5.5. However, these capsules were very weak and brittle, and an external strengthening capsulewas added by using magnesium cations. The membrane was then thinned with the surfactant lecithin,producing capsules with better adsorption attributes (316 mg Pb+2/g dry alginate vs. 267 mg Pb+2/g dryalginate without lecithin), most likely due to the thinner membrane and enhanced mass transfer. Thecapsules’ ability to adsorb other heavy-metal cations – copper (Cu2+), cadmium (Cd2+) and nickel (Ni2+)– was tested. Adsorption efficiencies were 219, 197 and 65 mg/g, respectively, and were correlated withthe cation’s affinity to alginate. Capsules with the sorbed heavy metals were regenerated by placing ina 1 M nitric acid suspension for 24 h. Capsules could undergo three regeneration cycles before becomingdamaged.