ABSTRACT

In this paper, the reaction mechanism for the adsorption of Zn²⁺ by synthetic triclinic Na-birnessite was studied by reacting synthetic triclinic Na-birnessite with Zn²⁺ in solution, thereby providing a theoretical basis for the purification of heavy metal ions in acid soil and water by triclinic birnessite. The adsorption effect of Zn²⁺ on Na-birnessite enhances with an increase in either reaction time or Na-birnessite dosage, as well as decrease of pH. Na-birnessite can effectively adsorb Zn²⁺ in acidic solutions without any secondary pollution, and the stronger the acidity, the better the treatment effect. In acidic conditions, H⁺ in solution exchanges with Na⁺ in the interlayer of triclinic Na-birnessite, then a small part of Zn²⁺ in solution exchanges with the Mn²⁺ produced during the triclinic-to-hexagonal phase transformation, and most of the Zn²⁺ forms a complex with OH⁻ on the octahedral layer, which loses protons due to the consumption of H⁺ ions. Finally, Zn²⁺ adsorbs above and below octahedral vacancies in hexagonal birnessite in either an octahedral or tetrahedral coordination.

摘要

本文通过合成三斜钠水钠锰矿与溶液中的Zn ²⁺反应，研究了合成三斜钠水钠锰矿吸附Zn ²⁺的反应机理，从而为酸中重金属离子的提纯提供理论依据。三斜水钠锰矿的土壤和水。^{Zn 2+}对Na-水钠锰矿的吸附效果随着反应时间或Na-水钠锰矿用量的增加以及pH值的降低而增强。水钠锰矿能有效吸附酸性溶液中的Zn ²⁺，无二次污染，酸性越强处理效果越好。在酸性条件下，溶液中的 H ⁺与 Na ^+交换在三斜钠水钠锰矿的夹层中，溶液中的小部分Zn ²⁺与三斜晶-六方相变过程中产生的Mn ²⁺发生交换，大部分Zn ^{2+与OH -}形成络合物。八面体层，由于 H ⁺离子的消耗而失去质子。最后，Zn ²⁺以八面体或四面体配位形式吸附在六方水钠锰矿中八面体空位的上方和下方。