Viana Thainara, Colónia João, Tavares Daniela S, Pinto João, Ferreira Nicole, Jacinto Jéssica, Pereira Eduarda, Henriques Bruno
LAQV-REQUIMTE - Associated Laboratory for Green Chemistry, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
ACS Sustain Resour Manag. 2024 Jul 11;1(7):1464-1474. doi: 10.1021/acssusresmgt.4c00104. eCollection 2024 Jul 25.
Given the significant industrial applications of rare earth elements (REEs), supply chain constraints, and negative environmental impacts associated with their extraction, finding alternative sources has become a critical challenge. Previously, we highlighted the potential of living sp. in the removal and pre-concentration of Y from a solution obtained by sequential acid leaching of spent fluorescent lamps (SFLs). Here, we extended that study to other REEs extracted from SFLs and evaluated the effect of pH (4.5-9.0), light exposure (absence, natural and supplemented with artificial light), and Hg (presence and absence). The results showed small differences in the removal of Y (23-30%) and other REEs at the different pH values, opening the scope of the methodology. However, sp. relative growth rate (RGR) was negatively affected in the higher acidity condition, without any visible signs of decay. In the absence of light, the RGR also decreased, which was accompanied by a halving of the removal efficiency compared to that with artificial light supplementation (40% for Y). Although Hg had minimal influence on the removal and concentration of REEs by sp., its presence in the enriched biomass is undesirable. Therefore, this contaminant was selectively removed from the solution using FeO@SiO/SiDTC nanoparticles before contact with the macroalgae (70% removal in 30 min; 99% in 72 h). In addition to easy solubilization, macroalgae enriched with REEs have a simpler composition compared to SFLs. Calcination of the biomass allowed the REEs to be further concentrated, with concentrations (130 mg/g for Y) up to 240 times higher than in typical apatite ore. This highlights enriched biomass as a sustainable alternative to traditional mining for obtaining these critical raw materials.
鉴于稀土元素（REEs）在工业上的重要应用、供应链限制以及与开采相关的负面环境影响，寻找替代来源已成为一项关键挑战。此前，我们强调了活的 sp. 在从废旧荧光灯（SFLs）顺序酸浸得到的溶液中去除和预富集钇（Y）的潜力。在此，我们将该研究扩展到从SFLs中提取的其他稀土元素，并评估了pH值（4.5 - 9.0）、光照（无光照、自然光照和补充人工光照）以及汞（存在和不存在）的影响。结果表明，在不同pH值下，钇（23 - 30%）和其他稀土元素的去除率差异较小，这为该方法开辟了应用范围。然而，在较高酸度条件下， sp. 的相对生长速率（RGR）受到负面影响，但没有任何明显的衰退迹象。在无光照条件下，RGR也下降，与补充人工光照相比，去除效率减半（钇的去除效率为40%）。尽管汞对 sp. 去除和富集稀土元素的影响最小，但在富集生物量中存在汞是不可取的。因此，在与大型藻类接触之前，使用FeO@SiO/SiDTC纳米颗粒从溶液中选择性去除这种污染物（30分钟内去除70%；72小时内去除99%）。除了易于溶解外，富含稀土元素的大型藻类与SFLs相比成分更简单。对生物量进行煅烧可使稀土元素进一步浓缩，其浓度（钇为130 mg/g）比典型磷灰石矿石中的浓度高出240倍。这突出了富集生物量作为获取这些关键原材料的传统采矿的可持续替代方案。
