Preparation of biopolymer microcapsules and their uptake properties for Cd2+ ions

Hitoshi Mimura, M. Outokesh, Y. Niibori, K. Tanaka

Research output: Chapter in Book/Report/Conference proceedingConference contribution

8 Citations (Scopus)


An extractant having a strong affinity for heavy metal ions, bis(2,4,4trimethylpentyl) monothiophosphinic acid (Cyanex 302, HA), was encapsulated in the alginate polymer matrices. The emulsification of HA extractant in microcapsules (MCs) resulted in a considerable reduction in the size of oil drops. The uptake rates of Cd2+ for MCs were enhanced compared to those for the matrices of CaALG and BaALG, and a large difference in uptake rate was observed within 10 h. The uptake of Cd2+ by MCs attained equilibrium within 20 h and Cd2+ ions were preferentially adsorbed on MCs even in the presence of 0.1 M HNO3 and 1 M NaOH. The uptake (%) of heavy metal ions, Ag, Cd, Pb and Cu, for HA-CaALG was above 96%, suggesting a simultaneous removal of soft metal ions. The uptake ability of Cd2+ for MCs is superior to that of conventional resins. The successive removal of Cd2+ ions was accomplished by a column packed with granular MCs. Various shapes of MCs such as fiber and film are also obtained. The microencapsulation techniques with alginate polymer are thus applicable to environmental remediation.

Original languageEnglish
Title of host publicationWaste Management in Japan
EditorsH. Itoh
Number of pages10
Publication statusPublished - 2004 Dec 1
EventSecond International Conference on Waste Management and the Environment - Rhodes, Greece
Duration: 2004 Sep 292004 Oct 1

Publication series

NameWaste Management in Japan


OtherSecond International Conference on Waste Management and the Environment


  • Alginate
  • Biopolymer
  • Cyanex 302
  • Emulsification
  • Environmental remediation
  • Extraction
  • Ion exchange
  • Microcapsule
  • Toxic heavy metals
  • Uptake

ASJC Scopus subject areas

  • Engineering(all)

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