C.E.A. - D.E.N. Laboratoire d'Analyses Radiochimiques et Chimiques, 13108 St Paul lez Durance, France.
J Hazard Mater. 2011 Jun 15;190(1-3):300-7. doi: 10.1016/j.jhazmat.2011.03.049. Epub 2011 Mar 22.
The removal of chloride, nitrate and sulfate ions from aqueous solutions by a macroporous resin is studied through the ion exchange systems OH(-)/Cl(-), OH(-)/NO(3)(-), OH(-)/SO(4)(2-), and HCO(3)(-)/Cl(-), Cl(-)/NO(3)(-), Cl(-)/SO(4)(2-). They are investigated by means of Langmuir, Freundlich, Dubinin-Radushkevitch (D-R) and Dubinin-Astakhov (D-A) single-component adsorption isotherms. The sorption parameters and the fitting of the models are determined by nonlinear regression and discussed. The Langmuir model provides a fair estimation of the sorption capacity whatever the system under study, on the contrary to Freundlich and D-R models. The adsorption energies deduced from Dubinin and Langmuir isotherms are in good agreement, and the surface parameter of the D-A isotherm appears consistent. All models agree on the order of affinity OH(-)<HCO(3)(-)<Cl(-)<NO(3)(-)<SO(4)(2-), and distinguish high energy processes (OH(-)/Cl(-), OH(-)/NO(3)(-), OH(-)/SO(4)(2-), Cl(-)/SO(4)(2-)) from lower energy systems (HCO(3)(-)/Cl(-), Cl(-)/NO(3)(-)). The D-A and D-R models provide the best fit to the experimental points, indicating that the micropore volume filling theory is the best representation of the ion exchange processes under study among other adsorption isotherms. The nonlinear regression results are also compared with linear regressions. While the parameter values are not affected, the evaluation of the best fitting model is biased by linearization.
通过 OH(-)/Cl(-)、OH(-)/NO(3)(-)、OH(-)/SO(4)(2-) 和 HCO(3)(-)/Cl(-)、Cl(-)/NO(3)(-)、Cl(-)/SO(4)(2-) 离子交换体系研究了大孔树脂从水溶液中去除氯离子、硝酸盐和硫酸盐离子。采用 Langmuir、Freundlich、Dubinin-Radushkevitch (D-R) 和 Dubinin-Astakhov (D-A) 单组分吸附等温线对它们进行了研究。通过非线性回归确定了吸附参数和模型拟合，并进行了讨论。无论研究的体系如何，Langmuir 模型都能很好地估计吸附容量，而 Freundlich 和 D-R 模型则不然。从 Dubinin 和 Langmuir 等温线推断出的吸附能非常吻合，D-A 等温线的表面参数也一致。所有模型都认为亲和力顺序为 OH(-)<HCO(3)(-)<Cl(-)<NO(3)(-)<SO(4)(2-)，并区分了高能过程 (OH(-)/Cl(-)、OH(-)/NO(3)(-)、OH(-)/SO(4)(2-)、Cl(-)/SO(4)(2-)) 和低能体系 (HCO(3)(-)/Cl(-)、Cl(-)/NO(3)(-))。D-A 和 D-R 模型对实验点的拟合最好，表明在其他吸附等温线中，微孔体积填充理论是研究离子交换过程的最佳表示。还比较了非线性回归结果与线性回归结果。虽然参数值不受影响，但线性化会使最佳拟合模型的评估产生偏差。
