Multi-metal contaminant mobilizations by natural colloids and nanoparticles in paddy soils during reduction and reoxidation

Li, Xinyang; Cao, Zhenyu; Du, Yanpei; Zhang, Yu; Wang, Jiajia; Ma, Xingmao; Hu, Pengjie; Luo, Yongming; Wu, Longhua

doi:10.1016/j.jhazmat.2023.132684

Cited by 10 publications

(2 citation statements)

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“…The fine nanoparticles which were ubiquitous in all soil colloid solutions were composed of OM, Fe, and Mn (oxy)hydroxides and clay minerals [29]. The consistency of the signal peaks might imply the close relation between Fe, Mn, OM, and clay, similar to that of Fe-OM-clay colloids found in another study [30]. The second fraction (F2) was identified after 35 min and corresponded to the remaining non-fractionated particles that were larger than 280 kDa but smaller than 450 nm (solutions were 450 nm filtered), and here defined as larger nanoparticles.…”

Section: Af4 and Elemental Analysis Of Different Soil Colloidssupporting

confidence: 69%

“…Pb could also be fixed on the surface OH group of Fe/Mn colloids like Cd. Pb could be more stably bound to colloid than Cd; this was also observed in another study [30]. Therefore, the transport of Pb was predominantly controlled by soil colloids, and environmental conditions that favored the formation of colloids, such as an increase in pH, would enhance the transport of Pb [17,19].…”

Section: Transport Of Soil Colloids Under Different Ph and Ionic Stre...supporting

confidence: 65%

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Influence of Soil Colloids on the Transport of Cd2+ and Pb2+ under Different pH and Ionic Strength Conditions

Ye,

Xu,

Zhong

et al. 2024

Agronomy

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The co-transport of contaminants by soil colloids can generate substantial environmental risk, and this behavior is greatly affected by environmental conditions. In this study, AF4-ICP-MS was used to investigate the size distribution and composition of Cd/Pb-bearing colloids; saturated sand column experiments were used to investigate the impact of soil colloids on the transport of Cd/Pb under different pH and ionic strength conditions. AF4-ICP-MS characterization showed that natural colloids were primarily associated with two sizes ranges: 0.3–35 KDa (F1, fine nanoparticles) and 280 KDa–450 nm (F2, larger nanoparticles), which mainly consisted of organic matter (OM), iron (Fe), and manganese (Mn) (oxy)hydroxides and clay minerals. Fine nanoparticles could strongly adsorb Cd and Pb under all environmental conditions. Mn and Fe (oxy)hydroxides generally formed under neutral to alkaline conditions and exhibited adsorption capabilities for Cd and Pb, respectively. Transport experiments were conducted under different pH and ionic strength conditions. At pH 3.0, soil colloids had little effect on the transport of Cd2+ and Pb2+. At pH 5.0, soil colloids inhibited the transport of Cd2+ by 16.1%, and Pb2+ recovery was still 0.0%. At pH 7.0 and 9.0, soil colloids facilitated the transport of Cd2+ by 15.6% and 29.6%, facilitated Pb2+ by 1.3% and 6.4%. At an ionic strength of 0, 0.005, and 0.01 mol L−1 NaNO3, soil colloids facilitated the transport of Cd2+ by 77.7%, 45.8%, and 15.6%, only facilitated the transport of Pb2+ by 46.2% at an ionic strength of 0 mol L−1 NaNO3. At an ionic strength of 0.05 mol L−1 NaNO3, soil colloids inhibited the transport of Cd2+ and Pb2+ by 33.1% and 21.0%, respectively. The transport of Cd2+ and Pb2+ facilitated by soil colloids was clearly observed under low ionic strength and non-acidic conditions, which can generate a potential environmental risk.

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Section: Af4 and Elemental Analysis Of Different Soil Colloidssupporting

confidence: 69%