Kinetic modeling of adsorption of vanadium and iron from acid solution through ion exchange resins

离子交换树脂吸附酸性溶液中钒和铁的动力学模拟

This study assessed the adsorption process and the reaction kinetics involved in the selective recovery of vanadium from an acid solution containing iron as an impurity.Four commercial resins were studied:Lewatit^(®)MonoPlus TP 209 XL,Lewatit^(®) TP 207,Dowex^(TM)M4195(chelating resin)and Lewatit^(®) MonoPlus S 200 H(strong cationic exchange resin).To investigate the effect of time on the adsorption process,batch experiments were carried out using the following initial conditions:pH 2.0,298 K,and a proportion of 1 g of resin to 50 mL of solution.The variation of pH over time was analyzed.Chelating resin released less H+ions as the adsorption occurred,resulting in a lower drop of pH when compared to S 200 H resin.Ion adsorption by the resins was also evaluated through FT-IR and SEM−EDS before and after the experiments.Among the evaluated kinetic models(pseudo-first order,pseudo-second order,Elovich and intraparticle diffusion models),the pseudo-second order model best fits the experimental data of the adsorption of vanadium and iron by all of the four resins.M4195 resin showed the highest recovery of vanadium and the lowest adsorption of iron.Kinetic data,which are fundamental to industrial processes applications,are provided.

评价从含铁杂质的酸性溶液中选择性回收钒的吸附过程和反应动力学。研究Lewatit^(®) MonoPlus TP 209XL、Lewatit^(®) TP 207、Dowex^(TM) M4195(螯合树脂)和Lewatit^(®) MonoPlus S 200 H (强阳离子交换树脂)4种工业树脂。在以下初始条件下进行批量实验:pH值2.0、温度298 K、树脂与溶液的比例1 g/50 mL。研究时间对吸附过程的影响,分析pH值随时间的变化情况。随着吸附作用的发生,与S 200H树脂相比,螯合树脂释放的H~+离子较少,导致pH值降低较少。通过FT-IR和SEM-EDS对实验前后树脂的离子吸附行为进行评价。在所评价的动力学模型(准一级、准二级、Elovich和颗粒内扩散模型)中,准二级模型与4种树脂对钒和铁的吸附实验数据最吻合。M4195树脂对钒的回收率最高,对铁的吸附率最低。本文提供了对于工业应用至关重要的动力学数据。