| abstract |
Heavy metals are removed from aq. solns. by adsorption on SiO2 gel with specific surface 200-1000 square m/g and pore vol. 0.2-1.8 ml/g.The SiO2 gel has specific surface 400-800 square m/g, pore vol. 0.4-1.5 ml/g, and particle size up to 500 (50-300) microns. Adsorption is (dis)continuous, in a column or on a screen. Adsorption is followed by regeneration with an aq. agent, pref. an acid, esp. 0.1-2 (0.1-1) mols.l of a mineral acid, and is (dis)continuous, in a column or on a screen. The heavy metal is isolated from the regenerant. |