Manganese dioxides (MnO₂) with a high affinity for thallium (Tl), strongly influence its fate and toxicity in aquatic environments. The crystal structure of MnO₂ plays a critical role in their activity for the uptake of heavy metals. However, few studies have examined the differences in interactions between Tl and various crystal structured MnO₂. In this study, the fundamental data on the sorption and oxidative reactivity of Tl(I) by MnO₂ with five known crystal structures (δ-, α-, γ-, β-, λ-MnO₂) was obtained at different pH values (5, 7, 12). The results showed that the uptake of Tl followed the order of δ-MnO₂ > α-MnO₂ > γ-MnO₂ > β-MnO₂ > λ-MnO₂, and increased with increasing pH for each MnO₂. Moreover, α-MnO₂ exhibited the strongest oxidation ability for Tl(I) at all the tested pH values, while β-MnO₂ could scarcely oxidize aqueous Tl(I). However, for δ-MnO_2, γ-MnO₂ and λ-MnO₂, the extent of Tl(I) oxidation was much larger at pH 12 than at pH 5 or 7, which was ascribed to the active species of TlOH involved in the redox process. Besides, the sorption of Tl(I) led to a decrease in crystallinity of δ-MnO₂ and α-MnO₂ but slightly impacted the structure of γ-MnO₂, β-MnO₂ and λ-MnO₂. These findings might contribute to understanding the immobilization processes of Tl by different crystal structured MnO₂ at various pH conditions.

对th（Tl）具有高亲和力的二氧化锰（MnO ₂）强烈影响其在水生环境中的命运和毒性。MnO ₂的晶体结构在其吸收重金属的活性中起着至关重要的作用。然而，很少有研究检查T1和各种晶体结构的MnO ₂之间相互作用的差异。在这项研究中，对铊（I）的吸附和氧化反应用MnO的基本数据₂具有五个已知的晶体结构（δ-，α-，γ-，β-，λ-MnO的₂在不同pH值获得） （5、7、12）。结果表明，T1的摄取，随后的次序δ-的MnO ₂ >α-MnO的₂ >γ-MnO的₂>β-MnO的₂ >λ-MnO的₂，以及对于每个增加的MnO pH升高₂。此外，α-MnO的₂表现出在所有测试的pH值下对铊（I）最强的氧化能力，而β-MnO的₂几乎无法氧化铊水溶液（I）。然而，对于δ-的MnO _2， γ-MnO的₂和λ-MnO的₂，T1的范围（I）的氧化是在pH 12比在pH 5或7，其归因于TlOH的活性种大得多的参与氧化还原过程。此外，T1的吸附（I）导致的结晶度δ-MnO的减少₂和α-MnO的₂但略有影响γ-MnO的结构₂，β-MnO的₂和λ-MnO的₂。这些发现可能有助于理解在各种pH条件下不同晶体结构的MnO ₂对T1的固定过程。