Adsorption of phenylalanine from aqueous solution onto active carbon and silica gel

The adsorption isotherms of phenylalanine from aqueous solution on active carbon andsilica gel at varying pH,and the influence of inorganic salt upon the ad rption have been studied(at 25℃).The adsorption amount of phcnylalanine on the silica gel is very low due to the strong ad-sorption of water by silica gel.The results on the active carbon show:(1)The adsorption is found to bepH-dependent,within pH 4.1—5.1 it increases with pH,within pH 5.1—11.8 it decreases with pH,atpH 5.1 the adsorption reaches its maximum;(2)The phenylalanine is adsorbed mainly in the formof zwitterion;(3)A certain amount of cations and anions of phenylalanine are also adsorbed with vander Waals interaction;(4)After adding NaCl,the adsorption of phenylalanine increases markedly.

Adsorption of phenylalanine from aqueous solution onto active carbon and silica gel