Nano zero-valent iron biochar (nZVI–BC), an environmentally-friendly functional material prepared from waste biomass, has attracted extensive attention. This material has potential to solve the problem of biomass conversion. However, the lack of a method of converting biomass to the nZVI–BC involved in biomass modification and pyrolysis hinders its further production and application. In this study, we introduced the green solvent polyethylene glycol 400 (PEG400) to a biomass (rice straw (RS)) modification system with FeCl₃·6H₂O, and activated RS was prepared to nZVI–BC by one-step pyrolysis. The addition of PEG400 promoted the hydrolysis of iron ion and improved the RS surface structure, promoting the attachment of Fe₂O₃ to the RS surface. The mild activation conditions with temperatures of 60, 80, and 100 °C and a time of 0.5 h prevented the excessive loss of the lignin component and were conducive to the formation of carbon skeletons. Amorphous carbon and Fe₂O₃ were subjected to redox reactions to form nZVI–BC with the assistance of reducing gas produced from pyrolysis. In addition, the prepared nZVI–BC was tested for dye (Congo red) removal, showing rapid absorption (70.60% at 5 min) and high catalysis in advanced oxidation (75.67% at 5 min, 90.00% at 60 min). This work proposed a novel mechanistic strategy for preparing nZVI–BC and set a foundation for its scaled production and application.

纳米零价铁生物炭（nZVI-BC）是一种利用废弃生物质制备的环保功能材料，受到广泛关注。这种材料有可能解决生物质转化问题。然而，缺乏将生物质转化为涉及生物质改性和热解的nZVI-BC的方法阻碍了其进一步的生产和应用。在本研究中，我们将绿色溶剂聚乙二醇 400 (PEG400) 引入生物质（稻草 (RS)）与 FeCl ₃ ·6H ₂ O 的改性体系中，并通过一步热解将活性 RS 制备成 nZVI–BC。_{PEG400的加入促进了铁离子的水解，改善了RS表面结构，促进了Fe 2} O ₃的附着到 RS 表面。温度60、80、100℃、时间0.5h的温和活化条件防止了木质素成分的过度损失，有利于碳骨架的形成。无定形碳和 Fe ₂ O ₃在热解产生的还原气体的帮助下进行氧化还原反应形成 nZVI–BC。此外，对制备的 nZVI-BC 进行了染料（刚果红）去除测试，显示出快速吸收（5 分钟时 70.60%）和高级氧化中的高催化作用（5 分钟时 75.67%，60 分钟时 90.00%）。该工作提出了制备 nZVI-BC 的新机理策略，为其规模化生产和应用奠定了基础。