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Abstract：
With the growing need for high-purity rare-earth elements (REEs), the separation of these REEs has received much attention recently. The objective of this research is to produce chitosan from shrimp waste, then modify it with different functionality, and investigate the adsorption properties of chitosan adsorbents towards La(III) ions. First, from shrimp waste, chitosan (ch) with a significant degree of deacetylation, purity, and solubility was produced. The purified chitosan was cross-linked with epichlorohydrin (ep), and then, it was modified with 3,6,9,12-tetraazatetradecane-1,14-diamine (HA) to produce polyaminated chitosan (HA@ep@Ch). The polycarboxylated/imine chitosan (CM@HA@ep@Ch) was obtained by treating polyaminated chitosan with chloroacetic acid in isopropyl alcohol. The chitosan adsorbents were characterized and applied for lanthanum recovery from synthetic and monazite leach liquor samples. The factors controlling the recovery process were studied and discussed. The performance of the adsorbents was achieved through equilibrium, dynamic, and isothermal studies. HA@ep@Ch and CM@HA@ep@Ch showed good performance for lanthanum recovery with a maximum capacity of 114.52 and 141.76 mg/g at 330 K, respectively. The isotherm parameters refer to the monolayer of lanthanum adsorbed into the adsorbents through chelation and ion exchange mechanisms. A 0.5-M HCl solution was found effective to elute 95.8% of the adsorbed lanthanum on HA@ep@Ch, and 93.4% of the adsorbed lanthanum on CM@HA@ep@Ch. The adsorbents showed greater selectivity in extracting La, Ce, Pr, Nd, and Sm (62-75%) from REE leach liquid compared to extracting other REEs (20-41%).
摘要：
随着对高纯稀土元素（REE）的需求不断增长，这些稀土元素的分离最近受到了很多关注。本研究的目的是从虾废物中生产壳聚糖，然后用不同的功能修改它，并考察了壳聚糖吸附剂对La(III)离子的吸附性能。首先,从虾废物中，壳聚糖（CH）具有显著的脱乙酰度，纯度,和溶解度产生。纯化的壳聚糖与表氯醇（EP）交联，然后,用3,6,9,12-四氮杂十四烷-1,14-二胺（HA）改性，生产多胺化壳聚糖（HA@ep@Ch）。通过在异丙醇中用氯乙酸处理多胺化壳聚糖，获得多羧基化/亚胺化壳聚糖（CM@HA@ep@Ch）。对壳聚糖吸附剂进行了表征，并将其用于合成和独居石浸出液样品中的镧回收。对控制回收过程的因素进行了研究和讨论。吸附剂的性能是通过平衡来实现的，动态,和等温研究。HA@ep@Ch和CM@HA@ep@Ch表现出良好的镧回收性能，在330K时的最大容量为114.52和141.76mg/g，分别。等温线参数是指通过螯合和离子交换机理吸附到吸附剂中的单层镧。发现0.5-MHCl溶液可有效洗脱HA@ep@Ch上95.8％的吸附镧，和93.4%的镧吸附在CM@HA@ep@Ch上。吸附剂在萃取La时显示出更大的选择性，Ce,Pr,Nd,与提取其他稀土元素(20-41%)相比，稀土元素浸出液中的Sm(62-75%)。
