Activated carbon adsorption of diethanolamine, methyl diethanolamine and their degradation products

Batch experiments were conducted to determine the adsorption of diethanolamine, methyl diethanolamine and their major degradation products from aqueous solutions by a lignite based (DARCO) and a bituminous coal based (SGL) carbon. The former was virtually ineffective whereas the latter adsorbed all organic compounds well, but its adsorptive capacity was extremely low (typically less than 3 m mol/g carbon). Adsorption isotherms were established for SGL carbon and used to predict, by means of Wang and Tien's Ideal Adsorbed Solution model, breakthrough curves for column adsorbers. The predictions agreed well with experimental measurements. It was found that saturated SGL carbon could not be regenerated by heating to 300°C, but HCl or HNO₃ treatment restored its adsorptive capacity to about 50% or 70%, respectively, of the original value.