TY - JOUR
T1 - Hydrocolloid liquid-core capsules for the removal of heavy-metal cations from water
AU - Nussinovitch, A.
AU - Dagan, O.
N1 - Publisher Copyright:
© 2015 Published by Elsevier B.V.
PY - 2015
Y1 - 2015
N2 - Liquid-core capsules with a non-crosslinked alginate fluidic core surrounded by a gellan membrane were produced in a single step to investigate their ability to adsorb heavy metal cations. The liquid-core gellan-alginate capsules, produced by dropping alginate solution with magnesium cations into gellan solution, were extremely efficient at adsorbing lead cations (267mg Pb2+/g dry alginate) at 25°C and pH 5.5. However, these capsules were very weak and brittle, and an external strengthening capsule was added by using magnesium cations. The membrane was then thinned with the surfactant lecithin, producing capsules with better adsorption attributes (316mg Pb+2/g dry alginate vs. 267mg Pb+2/g dry alginate without lecithin), most likely due to the thinner membrane and enhanced mass transfer. The capsules' ability to adsorb other heavy-metal cations - copper (Cu2+), cadmium (Cd2+) and nickel (Ni2+) - was tested. Adsorption efficiencies were 219, 197 and 65mg/g, respectively, and were correlated with the cation's affinity to alginate. Capsules with the sorbed heavy metals were regenerated by placing in a 1M nitric acid suspension for 24h. Capsules could undergo three regeneration cycles before becoming damaged.
AB - Liquid-core capsules with a non-crosslinked alginate fluidic core surrounded by a gellan membrane were produced in a single step to investigate their ability to adsorb heavy metal cations. The liquid-core gellan-alginate capsules, produced by dropping alginate solution with magnesium cations into gellan solution, were extremely efficient at adsorbing lead cations (267mg Pb2+/g dry alginate) at 25°C and pH 5.5. However, these capsules were very weak and brittle, and an external strengthening capsule was added by using magnesium cations. The membrane was then thinned with the surfactant lecithin, producing capsules with better adsorption attributes (316mg Pb+2/g dry alginate vs. 267mg Pb+2/g dry alginate without lecithin), most likely due to the thinner membrane and enhanced mass transfer. The capsules' ability to adsorb other heavy-metal cations - copper (Cu2+), cadmium (Cd2+) and nickel (Ni2+) - was tested. Adsorption efficiencies were 219, 197 and 65mg/g, respectively, and were correlated with the cation's affinity to alginate. Capsules with the sorbed heavy metals were regenerated by placing in a 1M nitric acid suspension for 24h. Capsules could undergo three regeneration cycles before becoming damaged.
KW - Alginate
KW - Gellan
KW - Heavy-metal cation
KW - Liquid-core capsule
KW - Protonation
UR - http://www.scopus.com/inward/record.url?scp=84935037214&partnerID=8YFLogxK
U2 - 10.1016/j.jhazmat.2015.06.013
DO - 10.1016/j.jhazmat.2015.06.013
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C2 - 26094245
AN - SCOPUS:84935037214
SN - 0304-3894
VL - 299
SP - 122
EP - 131
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
ER -