Biochar has attracted much attention for remediating the sites contaminated with heavy metals and radionuclides due to its low cost and high adsorption affinity. However, little is known about how colloidal biochar influences U(VI) transport in the environment. In this study, column experiments were conducted to investigate the individual and co-transport of U(VI) and biochar colloids (BC) in quartz sand heterogeneous media. Results showed that the transport of U(VI) in the individual transport system was pH-dependent and insensitive to ionic strength, whereas the individual BC transport was more sensitive to the changes in ionic strength compared to those in pH, indicating that electrostatic interaction plays a major role during BC transport but chemical interaction dominates U(VI) transport. In the presence of BC, the transport of U(VI) was significantly facilitated because of U(VI) adsorption on BC. The existence of low concentration of U(VI) (2.5 × 10⁻⁶ M), however, did not affect the breakthrough curves (BTCs) of BC, except for the co-transport at relatively high ionic strength (100 mM) where BC transport was impeded due to the decrease of colloid suspension stability. Colloid size exclusion effect was evidenced by the evolution of particle size and zeta potential of the effluents. The transport of BC in both the individual and co-transport systems could be described by a two-site kinetic attachment/detachment model. This work implies that a risk assessment of BC facilitated heavy metal transport should be carefully considered when biochar is applied to the remediation of heavy metal contaminated sites.

生物炭由于其低成本和高吸附亲和力而在重金属和放射性核素污染场地修复方面备受关注。然而，关于胶体生物炭如何影响环境中的 U(VI) 运输知之甚少。在这项研究中，进行了柱实验以研究 U(VI) 和生物炭胶体 (BC) 在石英砂非均质介质中的单独和共同运输。结果表明，U(VI)在个体转运系统中的转运是pH依赖性的，对离子强度不敏感，而个体BC转运对离子强度的变化比pH更敏感，表明静电相互作用发挥了作用。在 BC 运输过程中起主要作用，但化学相互作用在 U(VI) 运输中占主导地位。在BC面前，由于 U(VI) 在 BC 上的吸附，U(VI) 的运输得到了显着促进。存在低浓度 U(VI) (2.5 × 10^{然而， −6}  M) 不影响 BC 的穿透曲线 (BTC)，除了在相对高离子强度 (100 mM) 下的共转运，其中 BC 转运由于胶体悬浮稳定性的降低而受到阻碍。胶体尺寸排阻效应由流出物的粒径和 zeta 电位的演变证明。BC 在单独和共同运输系统中的运输可以通过双位点动力学附着/分离模型来描述。这项工作意味着在将生物炭应用于重金属污染场地的修复时，应仔细考虑对 BC 促进重金属运输的风险评估。