Adsorption behavior and mechanism of amino methylene phosphonic acid resin for Ag( I )

摘要

The sorption properties of amino methylene phosphonic resin(APAR) for Ag( I) were studied. The amino methylene phosphonic acid resin(APAR) has a good adsorption ability for Ag( I ) at pH=6.0 in the HAc-NaAc medium. The statically saturated adsorption capacity is 272 mg/g resin, Ag( I) adsorbed on APAR can be eluted by 5 percent (NH_2)_2CS-0.5 mol/L hydrochloric acid quantitatively. The adsorption rate constants determined under various temperatures are k_(15 deg C) = 3.89 X 10~(-5) s~(-1), k_(25 deg C) = 5.93 X 10~(-5) s~(-1), k_(35 deg C) = 7.59 X 10~(_5) s~(_1), k_(45 deg C) = 9.45 X 10~(-5) s~(-1), respectively. The apparent activation energy of adsorption, E_a is 22.8 kJ/mol, the enthalpy change (DELTA H) of sorption is 17.4 kJ/mol. The adsorption mechanism shows that the functional group of APAR coordinates with Ag( I ) to form coordination bond, the coordination molar ratio of the functional group of APAR to Ag( I) is 1 : 1.