Department of Soil Science, School of Agriculture, Shiraz University, Shiraz, Iran.
Department of Nanochemical Engineering Faculty of Advanced Technology, Shiraz University, Shiraz, Iran.
PLoS One. 2024 Sep 6;19(9):e0310054. doi: 10.1371/journal.pone.0310054. eCollection 2024.
Metal-organic frameworks (MOFs) are structures with high surface area that can be used to remove heavy metals (HMs) efficiently from the environment. The effect of MOFs on HMs removal from contaminated soils has not been already investigated. Monometallic MOFs are easier to synthesize with high efficiency, and it is also important to compare their structures. In the present study, Zn-BTC, Cu-BTC, and Fe-BTC as three metal-trimesic acid MOFs were synthesized from the combination of zinc (Zn), copper (Cu), and iron (Fe) nitrates with benzene-1,3,5-tricarboxylic acid (H3BTC) by solvothermal method. BET analysis showed that the specific surface areas of the Zn-BTC, Cu-BTC, and Fe-BTC were 502.63, 768.39 and 92.4 m2g-1, respectively. The synthesized MOFs were added at the rates of 0.5 and 1% by weight to the soils contaminated with 100 mgkg-1 of Zn, nickel (Ni), lead (Pb), and cadmium (Cd). Then quinoa seeds were sown in the treated soils. According to the results, the uptakes of all four HMs by quinoa were the lowest in the Cu-BTC 1% treated pots and the lowest uptakes were observed for Pb in shoot and root (4.87 and 0.39, μgpot-1, respectively). The lowest concentration of metal extracted with EDTA in the post-harvest soils was for Pb (11.86 mgkg-1) in the Cu-BTC 1% treatment. The lowest metal pollution indices were observed after the application of Cu-BTC 1%, which were 20.29 and 11.53 for shoot and root, respectively. With equal molar ratios, highly porous and honeycomb-shaped structure, the most crystallized and the smallest constituent particle size (34.64 nm) were obtained only from the combination of Cu ions with H3BTC. The lowest porosity, crystallinity, and a semi-gel like feature was found for the Fe-BTC. The synthesized Cu-BTC showed the highest capacity of stabilizing HMs, especially Pb in the soil compared to the Zn-BTC and the Fe-BTC. The highly porous characteristic of the Cu-BTC can make the application of this MOF as a suitable environmental solution for the remediation of high Pb-contaminated soils.
金属有机骨架（MOFs）是具有高表面积的结构，可以有效地从环境中去除重金属（HMs）。MOFs 对污染土壤中 HMs 去除的影响尚未得到研究。单金属 MOFs 更容易高效合成，比较它们的结构也很重要。在本研究中，通过溶剂热法将锌（Zn）、铜（Cu）和铁（Fe）硝酸盐与均苯三甲酸（H3BTC）结合，合成了 Zn-BTC、Cu-BTC 和 Fe-BTC 三种金属-均苯三甲酸 MOFs。BET 分析表明，Zn-BTC、Cu-BTC 和 Fe-BTC 的比表面积分别为 502.63、768.39 和 92.4 m2g-1。将合成的 MOFs 以 0.5%和 1%的重量添加到受 100 mgkg-1锌、镍（Ni）、铅（Pb）和镉（Cd）污染的土壤中。然后在处理过的土壤中播种藜麦种子。结果表明，在 Cu-BTC 1%处理的罐中，藜麦对所有四种 HMs 的吸收最低，在地上部和根部的 Pb 吸收最低（分别为 4.87 和 0.39μgpot-1）。收获后土壤中用 EDTA 提取的金属浓度最低的是 Pb（Cu-BTC 1%处理时为 11.86 mgkg-1）。在应用 Cu-BTC 1%后，观察到最低的金属污染指数，分别为地上部和根部的 20.29 和 11.53。在等摩尔比的情况下，仅从 Cu 离子与 H3BTC 的组合中获得了高多孔、蜂窝状结构、最结晶和最小组成颗粒尺寸（34.64nm）。Fe-BTC 的孔隙率、结晶度和半凝胶状特征最低。与 Zn-BTC 和 Fe-BTC 相比，合成的 Cu-BTC 表现出在土壤中稳定 HMs（特别是 Pb）的最高能力。Cu-BTC 的高多孔特性使其成为修复高 Pb 污染土壤的一种合适的环境解决方案。
