Knapik Ewa, Rotko Grzegorz, Piotrowski Marcin, Marszałek Marta
AGH University of Krakow, Faculty of Drilling, Oil and Gas, al. Mickiewicza 30, 30-059 Krakow, Poland.
Cracow University of Technology, Faculty of Chemical Engineering and Technology, Warszawska 24, 31-155 Krakow, Poland.
Materials (Basel). 2024 Dec 22;17(24):6269. doi: 10.3390/ma17246269.
Direct lithium extraction from unconventional resources requires the development of effective adsorbents. Crown ether-containing materials have been reported as promising structures in terms of lithium selectivity, but data on adsorption in real, highly saline brines are scarce. Crown ether-grafted graphene oxides were synthesized using 2-hydroxymethyl-12-crown-4, hydroxy-dibenzo-14-crown-4 and epichlorohydrin as a source of anchoring groups. The obtained carbonaceous materials were used to prepare chitosan-polyvinyl alcohol composites. The prepared materials (and intermediate products) were characterized using FTIR, XRD, Raman spectroscopy and SEM-EDS methods. Adsorption tests were performed in a pure diluted LiCl solution ([Li] = 200 mg/kg) as well as in a real, highly saline oilfield brine ([Li] ≈ 220 mg/kg), and the distribution coefficients (K) were determined. The obtained results show that K in pure LiCl solution was in the range of 0.9-75.6, while in brine it was in the range of 0.2-2.3. The study indicates that the high affinity for lithium in pure LiCl solution is mostly associated with the non-selective interaction of lithium ions with the graphene oxide matrix (COOH groups). It was also shown that the application of dibenzo-14-crown-4 moiety to graphene oxide modification groups increases the affinity of the composite material for lithium ions compared to an analogous material containing 12-crown-4-ether groups.
从非常规资源中直接提取锂需要开发有效的吸附剂。含冠醚材料在锂选择性方面被报道为有前景的结构，但关于在实际高盐卤水中吸附的数据却很稀少。使用2-羟甲基-12-冠-4、羟基二苯并-14-冠-4和环氧氯丙烷作为锚定基团的来源合成了冠醚接枝的氧化石墨烯。将所得含碳材料用于制备壳聚糖-聚乙烯醇复合材料。使用傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、拉曼光谱和扫描电子显微镜-能谱仪（SEM-EDS）方法对所制备的材料（及中间产物）进行了表征。在纯稀释LiCl溶液（[Li]=200mg/kg）以及实际的高盐油田卤水中（[Li]≈220mg/kg）进行了吸附试验，并测定了分配系数（K）。所得结果表明，在纯LiCl溶液中K的范围为0.9 - 75.6，而在卤水中其范围为0.2 - 2.3。该研究表明，在纯LiCl溶液中对锂的高亲和力主要与锂离子与氧化石墨烯基质（COOH基团）的非选择性相互作用有关。还表明，与含有12-冠-4-醚基团的类似材料相比，将二苯并-14-冠-4部分应用于氧化石墨烯改性基团可提高复合材料对锂离子的亲和力。
