Abstract The synthesis of biochar-metal oxide composites for removing heavy metals from aqueous solutions or remediating polluted soils has attracted increased attention. Amongst them, Fe oxide composites stand out due to possible magnetic properties and low price. Two types of Fe oxide-biochar composites were prepared by impregnation with ferric sulfate salts of biomass waste or corresponding hydrochar, followed by pyrolysis at 550 °C for 5 h. During pyrolysis, Fe increased carbonization, leading to biochar with low H/C values. Properties of Fe oxide-biochar composite greatly depend on the feedstock. The Fe content in the final Fe oxide-biochar was higher than in biochar obtained by direct pyrolysis of biomass waste. Some of Fe was in the form of FeS. Impregnation of hydrochar followed by pyrolysis lead to a Fe oxide-biochar composite with lower ash content and higher micro- and macro-porosity. In this case, the Fe was in the form of Fe oxides.

中文翻译：

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生物质废弃物水热碳化热解法制备氧化铁-生物炭复合材料

摘要 用于从水溶液中去除重金属或修复污染土壤的生物炭-金属氧化物复合材料的合成引起了越来越多的关注。其中，Fe 氧化物复合材料因其可能的磁性和低廉的价格而脱颖而出。通过用生物质废物的硫酸铁盐或相应的水碳浸渍，然后在 550°C 下热解 5 小时，制备了两种类型的氧化铁 - 生物炭复合材料。在热解过程中，Fe 增加了碳化，导致生物炭的 H/C 值较低。Fe 氧化物-生物炭复合材料的性质在很大程度上取决于原料。最终的氧化铁生物炭中的铁含量高于通过直接热解生物质废物获得的生物炭。一些 Fe 以 FeS 的形式存在。氢化碳浸渍然后热解导致铁氧化物-生物碳复合物具有较低的灰分含量和较高的微孔和大孔。在这种情况下，Fe 以 Fe 氧化物的形式存在。