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

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% (NH2)2CS-0.5 mol/L hydrochloric acid quantitatively. The adsorption rate constants determined under various temperatures are k15°C=3.89 × 10−5S−1, k25°C=5.93 × 10−5S−1, k35°C=7.59 × 10−5S−1, k45°C=9.45 × 10−5S−1, respectively. The apparent activation energy of adsorption, Ea is 22.8 kJ/mol, the enthalpy change (ΔH) 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.