Size effect of complexing microcapsules on copper ion extraction

In a previous work [J. Microencapsulation, in press], polyamide microcapsules containing a poly(acrylic acid) gel as a macromolecular ligand (PAA-CAPS) with a mean diameter of 210 mum were prepared using an original two-step polymerization process combining interfacial polycondensation and radical polymerization in a water in oil inverse emulsion system. Extractions of many divalent cations were examined. In this work, we proposed to synthesise by the same process, smaller microcapsules with a mean diameter of 10 mum (PAA-LCAPS). Reference polyamide microcapsules, i.e. without ligand were also synthesized (muCAPS) and (CAPS) [J. Microencapsulation, in press]. Microcapsule wall thickness was evaluated by SEM and TEM observations of microcapsule cross-section cuts, microcapsule water content was determined by thermogravimetric experiments. Specific surface area and total volume of the pore of microcapsules were determined by BET method based on N-2 adsorption/desorption. The comparison of the extractabilities and the stripping of Cu(II) into the various kind of microcapsules were examined. (C) 2002 Elsevier Science Ltd. All rights reserved.