Alginate microcapsules immobilized nanoscale zero-valent iron (M-NZVI), with diameters from several hundreds nanometers to several micrometers, were synthesized using ferric and calcium ions as the cross-linking cations, and then tested for removal of Pb(ii) from aqueous solution. The size of NZVI particles was only a few nanometers according to transmission electron microscopy (TEM) observation. The synthesized alginate microcapsules were stable in air for as long as they were dried and contained 9.97% of iron by weight. When 0.5 g L -1 of M-N...