Institute of Thermodynamics, Helmut-Schmidt-University / University of the Bundeswehr Hamburg, Holstenhofweg 85, 22043, Hamburg, Germany.
ChemistryOpen. 2022 May;11(5):e202200034. doi: 10.1002/open.202200034. Epub 2022 Mar 10.
Selective separation of heavy metal ions from acidic aqueous solutions is of strong interest for certain industrial processes, such as electroplating, as well as environmental protection, for example battery recycling. Amino-functionalized adsorbents are often discussed as suitable material for this purpose. Herein, two silica-based adsorbents functionalized with 3-aminopropyl- and 3-[2-[2-aminoethylamino]-ethylamino]-propyl-ligands resulting in adsorbents MonoA and TriA, respectively, were investigated regarding their separation behavior with focus on nickel(II) and cobalt(II) in batch as well as continuous flow experiments in acidic aqueous solutions. For both adsorbents, pH shifts into the alkaline range were observed in the process solutions, causing precipitation of metal hydroxides mainly in the particle pores in case of adsorbent MonoA and a combination of precipitation and adsorption regarding adsorbent TriA. Contrary to prior studies, our findings evidence that amino-functionalized adsorbents are not applicable for nickel(II) and cobalt(II) in selective adsorption processes and additionally demonstrate that, besides batch investigations, continuous flow experiments are essential for well-founded adsorbent selections in process development.
从酸性水溶液中选择性分离重金属离子对于某些工业过程（例如电镀）以及环境保护（例如电池回收）具有强烈的兴趣。氨基功能化的吸附剂通常被认为是适用于此目的的合适材料。本文研究了两种基于二氧化硅的吸附剂，它们分别用 3-氨丙基-和 3-[2-[2-氨乙基氨基]-乙基氨基]-丙基配体官能化，得到吸附剂 MonoA 和 TriA，分别研究了它们在酸性水溶液中的分批和连续流动实验中的分离行为，重点是镍（II）和钴（II）。对于这两种吸附剂，在处理溶液中观察到 pH 值向碱性范围移动，导致金属氢氧化物主要在吸附剂 MonoA 的颗粒孔中沉淀，而对于吸附剂 TriA 则是沉淀和吸附的组合。与先前的研究相反，我们的研究结果表明，氨基功能化的吸附剂不适用于镍（II）和钴（II）的选择性吸附过程，此外还表明，除了分批研究外，连续流动实验对于在工艺开发中进行合理的吸附剂选择至关重要。
