Selective Adsorption of La3+ Using a Tough Alginate-Clay-Poly(n-isopropylacrylamide) Hydrogel with Hierarchical Pores and Reversible Re-Deswelling/Swelling Cycles

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• 作者：Dongbei Wu ; Yawei Gao ; Wenjun Li ; Xiangning Zheng ; YongGui Chen ; Qigang Wang
• 刊名：ACS Sustainable Chemistry & Engineering
• 出版年：2016
• 出版时间：December 5, 2016
• 年：2016
• 卷：4
• 期：12
• 页码：6732-6743
• 全文大小：645K
• ISSN：2168-0485

文摘

Rare earth elements are an important strategic resource, and it is urgent that the rare earth industry continue to explore and develop novel separation methods and technologies. Herein, we fabricated an efficient semi-IPN alginate-clay-poly(n-isopropylacrylamide) (NIPAm) hydrogel by a frozen polymerization method with the help of UV light irradiation, where alginate was employed as the main adsorption functional compound. The as-prepared hydrogel exhibits tough, sponge-like hierarchical macroporous and reversible temperature-responsive characteristics. The maximum adsorption capacity of La³⁺ is 182 mg/g for the hydrogel composition of 5.0% NIPAm, 4.0% clay, and 3.0% alginate. The Langmuir isotherm fits the data very well, and the adsorption follows the pseudo-second-kinetic equation. The trace of La³⁺ ions can be effectively separated from the coexisting metal ions. After six repeated adsorption–desorption cycles, no obvious deformation of the shape and or loss of adsorption capacity of the bulk hydrogel is found, but the stress level of the original hydrogel is significantly enhanced. Our results indicate that the green, sustainable, adsorbent hydrogel may serve as a versatile platform for recovery, separation, and purification of rare earth ions and suggest its potential applications in the fields of hydrometallurgy industries and wastewater treatment.