Novel Production of Magnetite Particles via Thermochemical Processing of Digestate From Manure and Food Waste
Novel Production of Magnetite Particles via Thermochemical Processing of Digestate From Manure and Food Waste
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DOI：
10.1109/lmag.2019.2931975
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发表时间：
2019-01-01
影响因子：
1.2
通讯作者：
Trabold, Thomas A.
中科院分区：
文献类型：
--
作者：
Alberto, Diana Rodriguez;Repa, Kristen Stojak;Trabold, Thomas A.
食物垃圾的可持续管理已成为一项全球优先事项，因为包括填埋在内的传统处理方法会对环境产生重大影响。热化学处理是一种将食物垃圾转化为能量的技术，在高温下，食物垃圾在还原的氧气环境中转化为生物燃料。另一种转化技术是厌氧消化，在这种技术中，微生物消化可生物降解的物质，产生生物燃料和固体副产品“消化液”。我们测量了通过组合这些方法生产的“生物炭”的物理性质：将沼气用作商业规模的热化学处理系统的原料。在食物垃圾转化为能量的过程中产生了磁铁矿(Fe3O4)颗粒。这是特别出乎意料的，因为输入的材料都不是铁磁性的，在这个过程中也没有引入特定的铁前体。通过X射线荧光和直流磁测相结合的方法对Fe3O4进行了鉴定。零场冷却磁化温度曲线表明，在不同条件下制备的样品在125K附近发生了Verwey转变。室温磁化场曲线显示了不同样品的朗之万型曲线、技术饱和度和矫顽场H-C=98-130Oe。明显的Verwey转变、室温滞后和远高于室温的不可逆温度表明粒子是多域的。我们将Fe3O4的存在归因于固体物中自然存在的相对较高的Fe浓度和热化学转化过程的操作参数。高比表面积磁性生物炭具有广泛的潜在应用，包括吸附重金属、废水处理、超级电容器和导电聚合物复合材料。
Sustainable management of food waste has become a global priority because of the significant environmental impacts associated with conventional disposal methods, including landfilling. Thermochemical processing is a food-wasteto-energy conversion technology in which food waste materials are converted to biofuel in a reduced O-2 environment at elevated temperatures. Another conversion technology is anaerobic digestion, in which microorganisms digest biodegradable material, producing biofuel and solid byproducts "digestate." We measured the physical properties of "biochar" produced by combining these approaches: digestate was used as feedstock for a commercial-scale thermochemical processing system. Magnetite (Fe3O4) particles were produced during the food-waste-to-energy conversion process. This was particularly unexpected because none of the input materials were ferromagnetic, and no specific Fe precursors were introduced in the process. The Fe3O4 was identified through a combination of X-ray fluorescence and dc magnetometry. Zero-field cooled magnetization-temperature curves reveal a Verwey transition at similar to 125 K across samples prepared under various conditions. Room temperature magnetization-field loops show a Langevin-like curve, technical saturation, and coercive fields of H-C = 98-130 Oe across various samples. Clear Verwey transition, room temperature hysteresis, and an irreversibility temperature well above room temperature indicate that particles are multidomain. We attribute the presence of Fe3O4 to the relatively high concentration of Fe naturally present in the solid digestate and the operating parameters of the thermochemical conversion process. High surface area magnetic biochar has a variety of potential applications, including the adsorption of heavy metals, wastewater treatment, supercapacitors, and conductive polymer composites.