Removal of Co(Ⅱ) from aqueous solutions by NKC-9 strong acid resin
(Department of Applied Chemistry, Zhejiang Gongshang University, Hangzhou 310012, China)
Abstract: A strong acidic ion exchange resin (NKC-9) was used as a new adsorbent material for the removal of Co(Ⅱ) from aqueous solutions. The adsorption isotherm follows the Langmuir model. The maximum adsorption capacity of the resin for Co(Ⅱ) is evaluated to be 361.0 mg/g by the Langmuir model. It is found that 0.5 mol/L HCl solution provides effectiveness of the desorption of Co(Ⅱ) from the resin. The adsorption rate constants determined at 288, 298 and 308 K are 7.12×10−5, 8.51×10−5 and 9.85×10−5 s−1, respectively. The apparent activation energy (Ea) is 12.0 kJ/mol and the adsorption parameters of thermodynamic are ΔHΘ =16.1 kJ/mol, ΔSΘ=163.4 J/(mol·K), ΔGΘ298 K=−32.6 kJ/mol, respectively. The adsorption of Co(Ⅱ) on the resin is found to be endothermic in nature. Column experiments show that it is possible to remove Co(Ⅱ) ions from aqueous medium dynamically by NKC-9 resin.
Key words: strong acid resin; ion exchange; Co(Ⅱ); adsorption isotherm