海藻酸钠基吸附材料对铁离子的吸附动力学研究

Kinetic study of adsorption of iron ions on sodium-alginate-based adsorbent

以海藻酸钠-β-环糊精-聚乙烯醇为原料制备海藻酸钠基吸附剂(SA-β-CD-PVA),并考察其对于铁离子的吸附性能。通过吸附实验,分析材料吸附性能,并采用3种不同的吸附模型对吸附Fe^3+的实验结果进行理论分析。实验结果表明:在温度30—50℃范围内,准二级动力学模型能够很好地描述SA-β-CD-PVA对Fe^3+的吸附状况(R^2>0.99)。该吸附过程是一个化学反应速率控制的吸附过程,吸附活化能为74.13kJ/mol,吸附焓变为-6.406kJ/mol。SA-β-CD-PVA吸附剂对Fe^3+的吸附模式更加符合Langmuir等温方程(R2>0.99),表明Fe^3+在SA-β-CD-PVA吸附剂上的吸附模式是更接近于单分子吸附。

Sodium-alginate-based adsorbent (SA-β-CD-PVA) was prepared using sodium alginate,β-cyclodextrin and polyvinyl alcohol as raw materials. Its adsorption properties for iron ions were also investigated through adsorption experiments. Three different adsorption models were used to analyze the experimental results of Fe^3+ adsorption. The experimental results figure out that the pseudo-second-order kinetic model can well describe the adsorption of Fe^3+ on SA-β-CD-PVA ( R^2>0.99). The adsorption process is a chemical reaction rate-controlled adsorption process. The adsorption activation energy is 74.13 kJ/mol and the adsorption enthalpy is -6.406 kJ/ mol. The adsorption mode of Fe^ 3+ on SA-β-CD-PVA adsorbent was more in line with Langnuir isothermal equation ( R 2>0.99), which indicated that the adsorption mode of Fe^3+ on SA-β-CD-PVA adsorbent was closer to that of single molecule.