阴离子交换树脂回收水相中有机磷酸萃取剂

研究了阴离子交换树脂对水相中有机磷酸萃取剂的吸附。 通过比较不同的离子交换树脂对水相中2-乙基己基膦酸-单-2-乙基己基酯(P507)的去除率,发现大孔强碱性阴离子交换树脂(D201-OH)从水溶液中去除P507的能力最强,去除率可达99.24%。 而且当溶液在pH=1.0时,D201-OH对P507的吸附主要是分子吸附,其吸附等温线更适用于Langmuir模型;当溶液在pH=5.0时,阴离子交换反应占主导地位,其吸附等温线更适用于Freundlich模型。 研究还表明,D201-OH对P507的吸附在20 min内即达到吸附平衡时99.8%的吸附量。 通过动力学研究表明,拟一级动力学模型(R²>0.99)更适用于描述实验数据,并且吸附速率主要受膜扩散控制。 此外,吸附-解吸附循环8次后,D201-OH的吸附能力仍然保持在93%以上。 综上所述,D201-OH是有机磷酸类萃取剂的良好吸附剂,其吸附性能高效,循环过程稳定,因此可用于实际生产过程中回收有机磷酸萃取剂。

Recovery of Organphosphorus Extractants from Water by Anion Exchange Resin

The adsorption process of anion exchange resin to organphosphorus extractant in water was explored in this work. By comparing the removal of P507(2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester) in water with different anion exchange resins, it is found that D201-OH(macroporous strong basic anion exchange resin) has the strongest ability to remove P507 from water, and the removal rate can reach to 99.24%. Secondly, at pH=1.0, the adsorption of P507 on D201-OH is mainly molecular adsorption and its adsorption isotherm is better fit to the Langmuir model; at pH=5.0, the anion exchange reaction is dominant and its adsorption isotherm is more suitable for the Freundlich model. Furthermore, the adsorption capacity of D201-OH to P507 reaches 99.8% of which in the adsorption equilibrium in 20 min. Kinetic study shows that the pseudo-first-order model(R²>0.99) exhibits a better fit to describe the experimental data and the adsorption rate may be controlled mainly by the film diffusion. Moreover, the adsorption capacity of D201-OH remains above 93% after eight cycles of adsorption-desorption. In summary, D201-OH is an excellent adsorbent for organphosphorus extractants with high stability in the repeated cycle. Therefore, it can be used to recover organphosphorus extractant in the practical production process.