Extensive application of graphene-based nanomaterials will inevitably lead their release into soil. However, the retention and migration of graphene in natural soils are still unknown, due to the limitation on quantification methods. In this study, a carbon-14 isotope labeling technique was applied to systematically investigate the immobilization, transportation and transformation of ¹⁴C-labeled few-layer graphene (FLG) in two typical soils (red soil and black soil) with specifically different compositions. The adsorption capacity of red soil for FLG was 10.2 times higher than that of black soil at the same initial FLG concentration. Ferric oxides were identified as the predominant component governing the retention of FLG in soils through electrostatic attraction, leading to a significant difference on the adsorption performance between the two soils. Meanwhile, in the presence of naturally generated H₂O₂, ferric oxides were spontaneously employed as a catalyst to trigger a heterogeneous Fenton reaction to degrade FLG into the gas phase as CO₂, indicating an important pathway for the discharging of FLG from soil. Thus, this study clearly indicates the competitive roles of ferric oxides in restricting the mobility or facilitating the transformative release of graphene in natural soils, providing new insights into the environmental fate of carbon nanomaterials in real soil.

中文翻译：

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14C标记的几层石墨烯在天然土壤中的命运：三氧化二铁的竞争作用

石墨烯基纳米材料的广泛应用将不可避免地导致其释放到土壤中。然而，由于定量方法的限制，石墨烯在天然土壤中的保留和迁移仍是未知的。在这项研究中，采用了碳14同位素标记技术来系统地研究¹⁴的固定化，运输和转化在两种具有特定不同组成的典型土壤（红土和黑土）中用C标记的几层石墨烯（FLG）。在相同的初始FLG浓度下，红壤对FLG的吸附能力是黑土壤的10.2倍。氧化铁被认为是控制FLG通过静电吸引在土壤中的保留的主要成分，从而导致两种土壤之间吸附性能的显着差异。同时，在天然生成的H ₂ O ₂的存在下，三氧化_二铁被自发地用作催化剂，引发非均相的Fenton反应，从而将FLG降解为CO ₂气相。，这是从土壤中排放FLG的重要途径。因此，这项研究清楚地表明了三氧化二铁在限制天然土壤中石墨烯的迁移或促进其转化释放方面的竞争作用，从而为碳纳米材料在真实土壤中的环境命运提供了新的见解。