Adsorption behavior of gel-type weak acid resin (110-H) for Pb2+
(Department of Applied Chemistry, Zhejiang Gongshang University, Hangzhou 310035, China)
Abstract: The adsorption properties of a novel gel-type weak acid resin (110-H) for Pb2+ were investigated using chemical methods and IR spectrometry. The optimal adsorption condition of 110-H for Pb2+ is at pH=6.49 in HAc-NaAc medium and the statically saturated adsorption capacity is 485 mg/g at 298 K. Pb2+ adsorbed on 110-H resin can be eluted with 0.025 mol/L HCl quantificationally. The adsorption rate constants determined under the temperatures of 288, 298, 308 and 318 K are 2.46×10−5, 3.82×10−5, 4.46×10−5 and 5.71×10−5 s−1, respectively. The apparent activation energy, Ea, is 18.1 kJ/mol and the thermodynamic parameters of adsorption, ΔH=20.9 kJ/mol, ΔS=161 J/(mol∙K) and ΔG298 K =−48.0 kJ/mol, respectively. The adsorption behavior of 110-H resin for Pb2+ accords with the Langmuir isotherm. Infrared spectra show that the oxygen atoms of the functional group of resin coordinate with Pb2+ to form the coordination bands.
Key words: gel-type weak acid resin; adsorption; lead; mechanism