Breakthrough curve for adsorption of mercury(II) on polyaminated highly porous chitosan beads

The equilibrium isotherm and the breakthrough curve for adsorption of Hg(II) on polyaminated highly porous chitosan beads (PEI-CS) were compared with those for Unicellex UR-120H which was the best commercial chelate resin for removal of Hg(II) in Japan. As the intraparticle effective diffusivity D-eff in PEI-CS was about two times larger than that in UR 120H, and adsorption capacity Hg(II) on PEI-CS was also larger than that on UR-120H, adsorption of Hg(II) on PEI-CS appeared feasible technically. The intraparticle concentration profiles of Hg(II) were measured for different period of time using X-ray micro-analyzer. The value of D-eff was almost constant at 4 Re' 7, and the mean value was 3.86 x 10(?(-12) m(2)/s. The value od D-eff increased in proportion to the influent concentration of Hg(II) C-o,C-Hg. The pore diffusivity and surface diffusivity were determined using D-eff based on the parallel transport model of surface and pore diffusions. The result showed that both the pore and surface diffusions of Hg(II) in PEI-CS particle were significant. (C) 1997 IAWQ. Published by Elsevier Science Ltd.