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    面向浓海水提锂的SA/LiAl-LDHs复合凝胶制备及性能优化

    Preparation and performance optimization of SA/LiAl-LDHs composite gel for lithium extraction from concentrated seawater

    • 摘要: 为实现浓海水锂资源高效回收,本研究采用共沉淀法制备铝基锂吸附剂(LiAl-LDHs),以海藻酸钠(SA)为粘合剂,经CaCl2交联造粒制得高选择性、高稳定性且易应用的复合凝胶颗粒(GLDHs)。通过静态/动态吸附实验评价其提锂性能与机理,优化工艺参数。结果表明:LiAl-LDHs负载量20%的GLDHs-20颗粒吸附容量达6.53 mg·g−1,吸附符合准二级动力学模型(化学吸附主导);最优工艺下(高径比为2∶1、吸附流速为10 mL·min−1、进料量为10 BV,脱附液温度为25 ℃、脱附流速为5 mL·min−1、脱附液用量为2.5 BV),锂回收率达81.34%;高Na+/K+共存体系中选择性优异,15次循环后回收率仍超70%。研究结论表明,GLDHs-20是一种具有良好前景的工业级锂吸附剂,适用于从浓海水中提取锂资源,有助于推动资源的可持续利用和环境保护相关新技术的发展。

       

      Abstract: To achieve efficient recovery of lithium resources from concentrated seawater, an aluminum-based lithium adsorbent (LiAl-LDHs) was prepared via the co-precipitation method in this work. Using sodium alginate (SA) as the binder, composite gel particles (GLDHs) with high selectivity, excellent stability, and easy applicability were fabricated through CaCl2 cross-linking and granulation. Its lithium extraction performance and mechanism were evaluated through static/dynamic adsorption experiments, and the process parameters were optimized. The results showed that the GLDHs-20 beads with a LiAl-LDHs loading of 20% had an adsorption capacity of 6.53 mg·g−1, and the adsorption conformed to the pseudo-second-order kinetic model (dominated by chemical adsorption); under the optimal process conditions (aspect ratio of 2∶1, adsorption flow rate of 10 mL·min−1, feed volume of 10 BV, desorption solution temperature of 25 ℃, desorption flow rate of 5 mL·min−1, desorption solution volume of 2.5 BV), the lithium recovery rate reached 81.34%; it exhibited excellent selectivity in a high Na+/K+ coexistence system, and the recovery rate still exceeded 70% after 15 cycles. The research conclusions indicate that GLDHs-20 is a promising industrial-grade lithium adsorbent suitable for lithium extraction from concentrated seawater, which contributes to promoting the sustainable utilization of resources and the development of new technologies related to environmental protection.

       

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