离子交换树脂对氰化溶液中Fe(Ⅱ)和Fe(Ⅲ)的吸附行为

Adsorption behavior of Fe(Ⅱ) and Fe(Ⅲ) in cyanide solution to ion exchange resin

研究了大孔型弱碱性阴离子交换树脂L-300对于氰化溶液中Fe(CN)4-6和Fe(CN)3-6的吸附过程。结果表明,L-300树脂可有效地吸附Fe(Ⅱ)和Fe(Ⅲ)的氰化络合离子。25℃时,该树脂(湿树脂)对Fe(Ⅱ)和Fe(Ⅲ)的静态饱和吸附容量分别为5.301 mg/m L和8.585 mg/m L。该树脂对铁氰络合离子的吸附过程符合Lagergren二级速度方程式,以液膜扩散为主控步骤,对Fe(Ⅱ)和Fe(Ⅲ)的吸附速率常数分别为39.85 m L/(g·min)和55.56 m L/(g·min),表明对Fe(Ⅲ)的吸附速率要稍大于对Fe(Ⅱ)的吸附速率。L-300树脂对Fe(Ⅱ)和Fe(Ⅲ)的吸附符合Freundlich经验等温式,吸附过程的焓变分别为11.65 k J/mol和11.81 k J/mol,表明吸附是吸热过程。

The sorption properties, kinetic and thermodynamics behaviors of macroporous weak-base anion exchange resin L-300 for Fe（ CN）4-6 and Fe（ CN）3-6 as well as related parameters were studied. The results show that the L-300 resin has good ability for iron cyanocomplexes. The static saturated adsorptive capacity of Fe（ Ⅱ ） and Fe（ Ⅲ） are 5. 301 mg/mL and 8. 585 mg/mL,respectively at 25℃. The sorption process accords with La- gergren-equation and the liquid film diffusion is the predominating step of the sorption process. The adsorption rate constants for Fe（ Ⅱ ） and Fe（Ⅲ） are 39.85 mL/（g· min） and 55.56 mL/（g · min） , respectively, it in- dicates that adsorption rate of resin for Fe （ Ⅲ） is slightly larger than Fe （ Ⅱ ）. The sorption process obeys the Freundlich isotherm. The thermodynamic enthalpy changes of adsorption process are calculated as 11.65 kJ/mol and 11.81 kJ/mol, respectively. It indicates that sorption process is an endothermic process.