大容量阴离子交换树脂D296对水中铬(Ⅵ)的吸附

Cr(Ⅵ) Removal from Aqueous Solutions by a High-Capacity Strong Acid Resin D296

研究了大容量阴离子交换树脂D296在醋酸-醋酸钠缓冲液体系中对铬(Ⅵ)的吸附行为,同时进行了一系列实验研究系统变量对吸附量的影响。结果证明pH3.5,温度308 K为最佳吸附条件,静态饱和吸附量为325.8 mg×g^(-1),此时的吸附速率常数k_(308)=2.05×10^(-5)s^(-1);表观吸附活化能Ea=3.6 kJ×mol^(-1)。同时,热重、红外也显示了铬(Ⅵ)被吸附在树脂的表面。等温吸附符合Frundlich模型。热力学实验参数表明,该条件下吸附是自发的吸热过程。吸附后树脂可被5%NaOH-5%NaCl溶液解吸,解吸率94.7%。研究为从废水中去除铬(Ⅵ)展示了新的可能性。

Cr（Ⅵ） adsorption behavior of a high-capacity strong acid resin D296 was investigated in HAc-NaAc medium and effects of various factors on adsorption capacity were studied. The results show that the optimal p H and temperature for adsorption are 3.5 and 308 K, respectively. The static saturated adsorption capacity is 325.8 mg×g^-1 and the adsorption rate constant is 2.05×10^-5s^-1 under such conditions. The activation energy is 3.6 kJ×mol^-1. TGA-DSC and FTIR results indicate that chromium is adsorbed by the resin and the adsorption isotherm follows Frundlich model. Thermodynamic parameters indicate that Cr（Ⅵ） adsorption onto D296 is spontaneous and endothermic. The used resin can be effectively eluted by 5% NaOH-5% NaCl solution with a desorption rate of 94.7%. This work provides a new solution for Cr（Ⅵ） removal from aqueous solutions.