Graphene oxide (GO) nanosheets, often embedded in nano-composites, have been studied as promising materials for waste water purification, in particular to adsorb heavy metals and cationic organic contaminants. However, a broader range of potential applications of GO is still unexplored. This work investigated the potential applicability of GO for enhanced in-situ soil washing of secondary sources of groundwater contamination (i.e. the controlled recirculation of a washing GO suspension via injection/extraction wells). The laboratory study aimed at quantifying the capability of GO to effectively remove adsorbed methylene blue (MB) from contaminated sand. The tests were conducted in simplified conditions (synthetic groundwater at NaCl concentration of 20 mM, silica sand) to better highlight the key mechanisms under study. The results indicated a maximum sorption capacity of 1.6 mgMB/mgGO in moderately alkaline conditions. Even though the adsorption of MB onto GO slightly reduced the GO mobility in the porous medium, a breakthrough higher than 95% was obtained for MB/GO mass ratios up to 0.5. This suggests that a very high recovery of the injected particles should be also expected in the field.

氧化石墨烯 (GO) 纳米片通常嵌入纳米复合材料中，已被研究为有前途的废水净化材料，特别是吸附重金属和阳离子有机污染物。然而，GO 更广泛的潜在应用仍有待探索。这项工作调查了 GO 对地下水污染次要来源（即通过注入/提取井控制的洗涤 GO 悬浮液的再循环）增强原位土壤清洗的潜在适用性。实验室研究旨在量化 GO 有效去除受污染沙子中吸附的亚甲基蓝 (MB) 的能力。测试是在简化条件下进行的（NaCl 浓度为 20 mM 的合成地下水，硅砂），以更好地突出所研究的关键机制。结果表明在中等碱性条件下的最大吸附容量为 1.6 mgMB/mgGO。尽管 MB 在 GO 上的吸附略微降低了多孔介质中 GO 的迁移率，但对于高达 0.5 的 MB/GO 质量比，仍获得了高于 95% 的突破。这表明在现场也应该期望注入颗粒的非常高的回收率。