Adsorption behavior and mechanism of amino methylene phosphonic acid resin for Ag(Ⅰ)
(1. Department of Chemistry, Lishui University, Lishui 323000, China;
2. College of Food Science, Biotechnology and Environmental Engineering, Zhejiang Gongshang University, Hangzhou 310035, China)
2. College of Food Science, Biotechnology and Environmental Engineering, Zhejiang Gongshang University, Hangzhou 310035, China)
Abstract: 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℃=3.89×10−5 s−1, k25℃=5.93×10−5 s−1, k35℃=7.59×10−5 s−1, k45℃=9.45×10−5 s−1, respectively. The apparent activation energy of adsorption, Ea is 22.8 kJ/mol, the enthalpy change (∆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.
Key words: amino methylene phosphonic acid resin(APAR); Ag; adsorption; mechanism