Physical and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States.
Department of Civil and Environmental Engineering, Duke University, Durham, North Carolina 27708, United States.
Environ Sci Technol. 2021 May 4;55(9):6320-6328. doi: 10.1021/acs.est.0c08632. Epub 2021 Apr 2.
Scandium (Sc) has great potential for use in aerospace and clean energy applications, but its supply is currently limited by a lack of commercially viable deposits and the environmental burden of its production. In this work, a biosorption-based flow-through process was developed for extraction of Sc from low-grade feedstocks. A microbe-encapsulated silica gel (MESG) biosorbent was synthesized through sol-gel encapsulation of , a bacterium that selectively adsorbs Sc. Microscopic imaging revealed a high cell loading and macroporous structure, which enabled rapid mass transport and adsorption/desorption of metal ions. The biosorbent displayed high Sc selectivity against lanthanides and major base metals, with the exception of Fe(III). Following pH adjustment to remove Fe(III) from an acid leachate prepared from lignite coal, a packed-bed column loaded with the MESG biosorbent exhibited near-complete Sc separation from lanthanides; the column eluate had a Sc enrichment factor of 10.9, with Sc constituting 96.4% of the total rare earth elements. The MESG biosorbent exhibited no significant degradation with regard to both adsorption capacity and physical structure after 10 adsorption/desorption cycles. Overall, our results suggest that the MESG biosorbent offers an effective and green alternative to conventional liquid-liquid extraction for Sc recovery.
钪（Sc）在航空航天和清洁能源应用中具有巨大的潜力，但由于商业上可行的矿床有限，以及其生产带来的环境负担，其供应目前受到限制。在这项工作中，开发了一种基于生物吸附的流动工艺，用于从低品位原料中提取 Sc。通过溶胶-凝胶包埋 ，合成了一种微生物包埋硅胶（MESG）生物吸附剂， 是一种选择性吸附 Sc 的细菌。微观成像显示出高细胞负载和大孔结构，这使得金属离子能够快速进行质量传递和吸附/解吸。该生物吸附剂对镧系元素和主要基础金属表现出高 Sc 选择性，除了 Fe（III）。在用褐煤制备的酸浸出液中调整 pH 以去除 Fe（III）后，装满 MESG 生物吸附剂的填充床柱可实现 Sc 与镧系元素的近乎完全分离；柱洗脱液的 Sc 浓缩因子为 10.9，Sc 占总稀土元素的 96.4%。在 10 次吸附/解吸循环后，MESG 生物吸附剂的吸附容量和物理结构均没有明显降解。总体而言，我们的结果表明，MESG 生物吸附剂为传统的液-液萃取回收 Sc 提供了一种有效且绿色的替代方法。
