Hydrogen production and heavy metal immobilization using hyperaccumulators in supercritical water gasification
Hydrogen production and heavy metal immobilization using hyperaccumulators in supercritical water gasification
复制标题
超临界水气化中使用超富集器的氢气生产和重金属固定化
DOI：
10.1016/j.jhazmat.2020.123541
复制
发表时间：
2021-01-15
影响因子：
13.6
通讯作者：
Lam, Su Shiung
中科院分区：
文献类型：
--
作者：
Su, Wei;Liu, Ping;Lam, Su Shiung
植物修复过程中使用的超积累物因其丰富的重金属含量而引起环境问题。重要的是要减少环境风险，防止HM重新进入生态循环，从而进入人类的食物网。本研究采用超临界水气化（SCWG）技术将Sedum plumbizincicola转化为氢气（H2）气体，并将HMs固定为生物炭。温度在380 ~ 440℃范围内H2产率最高，达到2.74 mol/kg，高温下自由基反应和蒸汽重整反应可能是H2产率的主要机理。通过气相色谱-质谱（GC-MS）和核磁共振（NMR）对生物油的分析表明，芳香族化合物、含氧化合物和酚类化合物被降解为富h2气体。温度的升高提高了HM的固定化效率（达到99.2%），这可能是由于快速形成的生物炭有助于吸附HM。然后，这些HMs通过与生物炭上的无机组分（如硅酸盐、SiO2和Al2O3）的络合作用，在化学上转化为稳定的形式。因此，SCWG工艺被证明是一种很有前途的方法，通过将有害的HMs固定到生物炭中，同时产生增值的富h2气体，来分散超蓄能器。
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 (H2) gas and to immobilize HMs into biochar. The H2 production correlated with temperature ranging from 380 to 440 degrees C with the highest H2 yield of 2.74 mol/kg at 440 degrees C. The free-radical reaction and steam reforming reaction at high temperatures were likely to be the mechanism behind the H2 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 H2-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, SiO2, and Al2O3. 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 H2-rich gases.