A particle size change occurs ubiquitously during transport of nanoparticles in the subsurface and is likely to influence nanoparticle fate and transport behaviours. The effects of this size change on the subsequent transport of eluted graphene oxide (GO) in saturated media were therefore investigated under various ionic strength (IS) and filtration degree conditions. Aggregation kinetics revealed that size change after filtration only occurred at relatively high IS conditions. As the filtration column length increased from 15 cm to 30 cm, sizes of aggregates in filtrates for large-sized and small-sized GO populations decreased and increased, respectively, and both approached to their steady aggregate sizes. Aggregation, straining, sedimentation, bridging, DLVO interactions, or a combination of these mechanisms were involved in the size change process during filtration. After passing through the 30 cm filtration column, filtered GO, in comparison with original GO, exhibited stronger mobility than expected, suggesting neglecting size change will result in underestimation of the nanoparticle mobility in porous media.

粒径变化在地下纳米颗粒的运输过程中无处不在，并且可能影响纳米颗粒的命运和运输行为。因此，在各种离子强度（IS）和过滤度条件下，研究了尺寸变化对洗脱的氧化石墨烯（GO）在饱和介质中后续传输的影响。聚集动力学表明，过滤后的尺寸变化仅在相对较高的IS条件下发生。随着过滤柱长度从15 cm增加到30 cm，大型和小型GO种群的滤液中聚集体的大小分别减小和增加，并且都接近其稳定的聚集体大小。聚集，拉力，沉降，桥接，DLVO相互作用，或这些机制的组合参与了过滤过程中的尺寸变化过程。通过30厘米的过滤柱后，与原始GO相比，过滤后的GO表现出比预期强的迁移率，这表明忽略大小变化将导致多孔介质中纳米颗粒迁移率的低估。