Removal of Cadmium(II) by hydrated manganese dioxide: behaviour and mechanism at different pH

Wang, Yao; Xie, Wanzhen; Xie, Fencun

doi:10.1080/09593330.2022.2064240

Cited by 2 publications

(5 citation statements)

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“…Manganese oxide could exert strong specific adsorption effects on heavy metals and may thus significantly increase the proportion of reducible heavy metal components. However, for the weakly alkaline soil in this study, the application of these two amendments alone had almost no Cd passivation effects, which may be due to their insignificant effects on the soil pH or attributed to their relatively low adsorption or surface complexation capacity for Cd in the weakly alkaline soil [15,47,49,50].…”

Section: Discussionmentioning

confidence: 56%

“…Wang et al [22] found that the biochar-zeolitehumus compound amendment had an excellent Cd passivation effect in weakly alkaline soils because it could convert the acid-soluble Cd to the Cd bound to the reducible fraction with a higher stability. In this study, MnO 2 -based compound amendments showed substantial synergistic effects on Cd immobilization, which may be ascribed to the similar Cd passivation mechanisms of manganese oxides and organic components, both of which may immobilize Cd via the adsorption or surface complexation [2,21,49]. Manganese oxides have large specific surface areas and abundant active specific adsorption sites on the surface [20,49].…”

Section: Discussionmentioning

confidence: 67%

“…In this study, MnO 2 -based compound amendments showed substantial synergistic effects on Cd immobilization, which may be ascribed to the similar Cd passivation mechanisms of manganese oxides and organic components, both of which may immobilize Cd via the adsorption or surface complexation [2,21,49]. Manganese oxides have large specific surface areas and abundant active specific adsorption sites on the surface [20,49]. Cd could be specifically adsorbed via the surface of manganese oxides by forming monodentate or bidentate inner layer complexes [20,49].…”

Section: Discussionmentioning

confidence: 71%

“…Manganese oxides have large specific surface areas and abundant active specific adsorption sites on the surface [20,49]. Cd could be specifically adsorbed via the surface of manganese oxides by forming monodentate or bidentate inner layer complexes [20,49]. The tunnel structure of manganese oxides may also easily provide space for foreign ions [20,49].…”

Section: Discussionmentioning

confidence: 99%

“…Cd could be specifically adsorbed via the surface of manganese oxides by forming monodentate or bidentate inner layer complexes [20,49]. The tunnel structure of manganese oxides may also easily provide space for foreign ions [20,49]. Meanwhile, Cd could complex with the abundant carboxyl or hydroxyl groups on the surface of organic components in MnO 2 -based compound materials, thereby enhancing the adsorption and complexation of Cd in soils and improving the passivation effects [18,56].…”

Section: Discussionmentioning

confidence: 99%

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Interactive Effects of Inorganic–Organic Compounds on Passivation of Cadmium in Weakly Alkaline Soil

Tong,

Huang,

Liu

et al. 2023

Agronomy

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The availability of cadmium (Cd) in soils is an important factor affecting the safe production of crops. The application of certain soil amendments could reduce the soil Cd availability via the passivation of Cd. However, the passivation of Cd in alkaline soils is limited. Thus, different inorganic and organic amendments and their compound treatments were selected as passivators for reducing the Cd availability in a weakly alkaline farmland soil. The effects of different single and compound amendments on the soil pH and Cd availability, as well as the interactions between inorganic and organic components in immobilizing Cd, were evaluated. The results showed that the inorganic–organic compound amendments can considerably improve the Cd passivation efficiency in the weakly alkaline soil. Moreover, the inorganic and organic components in the compound amendments exerted different synergistic effects in Cd passivation. The manganese dioxide-based compound amendments showed the most remarkable synergistic effects, while the calcium–magnesium–phosphate fertilizer-based compound amendments displayed the weakest synergistic effects. The underlying mechanisms regarding the synergistic effects may be that the compound amendments enhanced the adsorption/specific adsorption, co-precipitation, and surface complexation of Cd in the alkaline soil. A more balanced recommendation for Cd immobilization in the weakly alkaline soil may be manganese dioxide-based compound amendments, given the synergistic effects and Cd immobilization capabilities of various compound materials. This study may provide a theoretical foundation for the passivation remediation of alkaline Cd-contaminated farmland soils by using inorganic–organic compound amendments.

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Section: Discussionmentioning

confidence: 56%