Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering , Fudan University , Shanghai 200433 , People's Republic of China.
Shanghai Institute of Pollution Control and Ecological Security , Shanghai 200092 , People's Republic of China.
Environ Sci Technol. 2019 Jun 4;53(11):6580-6586. doi: 10.1021/acs.est.9b00262. Epub 2019 May 22.
Plants used for phytoremediation of contaminated soil are often enriched in certain metals present in the soil. However, the role of the inherent metal content of the plants on their recycling by hydrothermal liquefaction (HTL) has not been considered in previous studies. The present study showed that Rhus chinensis plants grown in highly Pb-polluted soil can release inherent metals (such as Pb, K, Ca, Na, and Mg) into the HTL solution, further enhancing the production of formic and acetic acids and decreasing the yield of levulinic acid. Theoretical calculations using HTL reactions of model compounds showed that a low Pb content could enhance production of levulinic and formic acids via catalysis of the rehydration reaction for 5-(hydroxymethyl)furfural, while a high Pb content promoted the decomposition of levulinic acid to acetic acid. Fourier transform ion cyclotron resonance mass spectrometry analysis confirmed that Pb preferentially promoted the depolymerization of macromolecular compounds with the lignin structure. In general, the inherent metals occurring in the phytoremediation plant influenced the production of organic acids during HTL recycling. Undoubtedly, the combination of phytoextraction and HTL reaction can present a practical pathway toward a sustainable soil remediation technology.
用于污染土壤植物修复的植物通常会富集土壤中存在的某些金属。然而，在之前的研究中，并未考虑植物固有的金属含量对其通过水热液化（HTL）再循环的作用。本研究表明，在高 Pb 污染土壤中生长的麻疯树可以将固有金属（如 Pb、K、Ca、Na 和 Mg）释放到 HTL 溶液中，进一步促进甲酸和乙酸的生成，降低乙酰丙酸的产率。使用模型化合物的 HTL 反应进行理论计算表明，低 Pb 含量可以通过 5-（羟甲基）糠醛的水合反应的催化来增强乙酰丙酸和甲酸的生成，而高 Pb 含量则促进了乙酰丙酸分解为乙酸。傅里叶变换离子回旋共振质谱分析证实，Pb 优先促进具有木质素结构的大分子化合物的解聚。总的来说，在 HTL 再循环过程中，植物修复植物中存在的固有金属会影响有机酸的生成。毫无疑问，植物提取和 HTL 反应的结合可以为可持续的土壤修复技术提供一种实用途径。
