Recovery of HgCl2 Using Polyaminated Highly Porous Chitosan Beads. Effect of Salt and Acid.

Abstract

Adsorption of Hg(II) on polyaminated highly porous chitosan (PEI-CS) from washing solutions of refuse incinerator flue gases is technically feasible. Equilibrium isotherms for adsorption Hg(II) on PEI-CS were measured by a batch method. The experimental data correlate well with the Langmuir equation in the range of about 5 to 70 mol/m3 Hg(II) aqueous solution. When HCl exists in Hg(II) solution, the saturation capacity and equilibrium constant for adsorption of Hg(II) on PEI-CS decrease with increasing concentration of HCl, CHCl. When NaCl is in Hg(II) solution, the equilibrium constant is constant, but the saturation capacity decreases with an increase in the concentration of NaCl. Breakthrough curves for adsorption of 10 mol/m3 Hg(II) were measured using a PEI-CS packed column at Re′ = 5. The intraparticle effective diffusivities Deff of Hg(II) are determined from the experimental breakthrough curves. When HCl exists in Hg(II) solution, Deff increases with increasing C0, HCl when C0, HCl 180 mol/m3, it shows a constant value, which is about 8 times larger than that measured in pure Hg(II) aqueous solution. When NaCl is in Hg(II) solution, the shapes of the breakthrough curves are similar to those in pure Hg(II) solution. Deff is kept constant in the range of 0 ≤ C0, NaCl ≤ 1000 mol/m3.