To investigate co-transport behavior of ammonium and colloids in saturated porous media under different hydrochemical conditions, NH4+ was selected as the target contaminant, and silicon and humic acid (HA) were selected as typical organic and inorganic colloids in groundwater. Column experiments were then conducted to investigate the transport of NH4+ colloids under various hydrochemical conditions. The results showed that because of the different properties of colloidal silicon and HA after combining with NH4+, the co-transport mechanism became significantly different. During transport by the NH4+-colloid system, colloidal silicon occupied the adsorption sites on the medium surface to promote the transport of NH4+, while humic acid (HA) increased the number of adsorption sites of the medium to hinder the transport of NH4+. The co-transport of NH4+ and colloids is closely related to hydrochemical conditions. In the presence of HA, competitive adsorption and morphological changes of HA caused NH4+ to be more likely to be transported at a higher ionic strength (IS = 0.05 m, CaCl2) and alkalinity (pH = 9.3). In the presence of colloidal silicon, blocking action caused the facilitated transport to be dependent on higher ionic strength and acidity (pH = 4.5), causing the recovery of NH4+ to improve by 7.99%, 222.25% (stage 1), and 8.63%, respectively. Moreover, transport increases with the colloidal silicon concentrations of 20 mg/L then declines at 40 mg/L, demonstrating that increased concentrations will lead to blocking and particle aggregation, resulting in delayed release in the leaching stage. Graphical abstract.

中文翻译：

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铵和胶体在不同水化学条件下在饱和多孔介质中的共运行为。

为了研究铵盐和胶体在饱和多孔介质中在不同水化学条件下的共运行为，选择了NH4 +作为目标污染物，并选择了硅和腐植酸（HA）作为地下水中的典型有机和无机胶体。然后进行柱实验以研究各种水化学条件下NH4 +胶体的运输。结果表明，由于胶态硅与HA与NH4 +结合后的性质不同，其共运机理明显不同。在通过NH4 +-胶体系统转运期间，胶体硅占据了介质表面的吸附位点，从而促进了NH4 +的转运，而腐殖酸（HA）增加了介质的吸附位点数量，从而阻碍了NH4 +的转运。NH4 +和胶体的共同运输与水化学条件密切相关。在存在HA的情况下，HA的竞争性吸附和形态变化导致NH4 +更有可能在更高的离子强度（IS = 0.05 m，CaCl2）和碱度（pH = 9.3）下运输。在胶态硅的存在下，阻断作用导致促进的转运取决于更高的离子强度和酸度（pH = 4.5），使NH4 +的回收率提高了7.99％，222.25％（第1阶段）和8.63％，分别。此外，当胶体硅浓度为20 mg / L时，运输增加，然后在40 mg / L时下降，这表明增加的浓度将导致阻塞和颗粒聚集，从而导致浸出阶段的释放延迟。图形概要。