Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University , Shanghai 200433, China.
Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder , Boulder, Colorado 80309, United States.
Environ Sci Technol. 2018 Feb 20;52(4):2225-2234. doi: 10.1021/acs.est.7b03756. Epub 2018 Feb 8.
Waste Sedum plumbizincicola, a zinc (Zn) hyperaccumulator during phytoremediation, was recycled via a subcritical hydrothermal liquefaction (HTL) reaction into multiple streams of products, including hydrochar, bio-oil, and carboxylic acids. Results show approximately 90% of Zn was released from the S. plumbizincicola biomass during HTL at an optimized temperature of 220 °C, and the release risk was mitigated via HTL reaction for hydrochar production. The low-Zn hydrochar (∼200 mg/kg compared to original plant of 1558 mg/kg) was further upgraded into porous carbon (PC) with high porosity (930 m/g) and excellent capability of carbon dioxide (CO) capture (3 mmol/g). The porosity, micropore structure, and graphitization degree of PCs were manipulated by the thermal recalcitrance of hydrochar. More importantly, results showed that the released Zn could effectively promote the production of acetic acid via the oxidation of furfural (FF) and 5-(hydroxymethyl)-furfural (HMF). Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with negative electrospray ionization analysis confirmed the deoxygenation and depolymerization reactions and the production of long chain fatty acids during HTL reaction of S. plumbizincicola. This work provides a new path for the recycling of waste hyperaccumulator biomass into value-added products.
在植物修复过程中，锌超积累植物菫菜被回收再利用，通过亚临界水热液化（HTL）反应转化为多种产品，包括水焦、生物油和羧酸。结果表明，在优化温度为 220°C 的条件下，90%左右的锌从菫菜生物质中释放出来，通过 HTL 反应生产水焦，可以降低释放风险。低锌水焦（与原始植物的 1558mg/kg 相比，约为 200mg/kg）进一步升级为具有高孔隙率（930m/g）和优异二氧化碳（CO）捕集能力（3mmol/g）的多孔碳（PC）。PC 的孔隙率、微孔结构和石墨化程度可通过水焦的热稳定性来调控。更重要的是，研究结果表明，释放的锌可以通过糠醛（FF）和 5-羟甲基糠醛（HMF）的氧化有效促进乙酸的生成。采用负离子电喷雾电离分析的傅里叶变换离子回旋共振质谱（FT-ICR MS）证实了菫菜在 HTL 反应过程中的脱氧和解聚反应以及长链脂肪酸的生成。这项工作为将废弃的超积累植物生物质回收再利用为高附加值产品提供了一条新途径。
