Su Wei, Liu Ping, Cai Changqing, Ma Hongzhi, Jiang Bo, Xing Yi, Liang Yunyi, Cai Liping, Xia Changlei, Le Quyet Van, Sonne Christian, Lam Su Shiung
Department of Environmental Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China.
Department of Environmental Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China.
J Hazard Mater. 2021 Jan 15;402:123541. doi: 10.1016/j.jhazmat.2020.123541. Epub 2020 Jul 25.
The dispersion of hyperaccumulators used in the phytoremediation process has caused environmental concerns because of their heavy metal (HM) richness. It is important to reduce the environmental risks and prevent the HM to reenter the ecological cycle and thereby the human food web. In this work, supercritical water gasification (SCWG) technology was used to convert Sedum plumbizincicola into hydrogen (H) gas and to immobilize HMs into biochar. The H production correlated with temperature ranging from 380 to 440 ℃ with the highest H yield of 2.74 mol/kg at 440 ℃. The free-radical reaction and steam reforming reaction at high temperatures were likely to be the mechanism behind the H production. The analyses of bio-oil by the Gas Chromatography-Mass Spectrometer (GC-MS) and Nuclear magnetic resonance spectroscopy (NMR) illustrated that the aromatic compounds, oxygenated compounds, and phenols were degraded into H-rich gases. The increase of temperature enhanced the HM immobilization efficiency (>99.2 % immobilization), which was probably due to the quickly formed biochar that helped adsorb HMs. Then those HMs were chemically converted into stable forms through complexation with inorganic components on biochar, e.g., silicates, SiO, and AlO. Consequently, the SCWG process was demonstrated as a promising approach for dispersing hyperaccumulators by immobilizing the hazardous HMs into biochar and simultaneously producing value-added H-rich gases.
植物修复过程中使用的超富集植物的扩散因其富含重金属（HM）而引发了环境问题。降低环境风险并防止重金属重新进入生态循环进而进入人类食物网至关重要。在这项工作中，采用超临界水气化（SCWG）技术将东南景天转化为氢气（H₂），并将重金属固定在生物炭中。氢气产量与380至440℃的温度相关，在440℃时氢气产量最高，为2.74 mol/kg。高温下的自由基反应和蒸汽重整反应可能是产氢的背后机制。通过气相色谱 - 质谱联用仪（GC - MS）和核磁共振光谱（NMR）对生物油的分析表明，芳香族化合物、含氧化合物和酚类被降解为富含氢气的气体。温度升高提高了重金属固定效率（固定率>99.2%），这可能是由于快速形成的生物炭有助于吸附重金属。然后，这些重金属通过与生物炭上的无机成分（如硅酸盐、SiO₂和Al₂O₃）络合而化学转化为稳定形式。因此，超临界水气化过程被证明是一种很有前景的方法，可通过将有害重金属固定在生物炭中并同时生产增值的富氢气体来处理超富集植物。
