Pertechnetate (⁹⁹TcO₄^–), a physiologically toxic radioactive anion, is of great concern due to its high mobility in environmental contamination remediation. Although the soluble oxyanion can be photoreduced to sparingly soluble TcO₂·nH₂O, its effective removal from a strongly acidic aqueous solution remains a challenge. Here, we found that low-crystalline nitrogen-doped titanium oxide (N-TiO₂, 0.6 g L^–1) could effectively uptake perrhenate (ReO₄^–, 10 mg L^–1, a nonradioactive surrogate for TcO₄^–) with 50.8% during 360 min under simulated sunlight irradiation at pH 1.0, but P25 and anatase could not. The nitrogen active center formed by trace nitrogen doping in N-TiO₂ can promote the separation and transfer of photogenerated carriers. The positive valence band value of N-TiO₂ is slightly higher than those of P25 and anatase, which means that the photogenerated holes have a stronger oxidizability. These holes are involved in the formation of strong reducing ^•CO₂^– radicals from formic acid oxidation. The active radicals convert ReO₄^– to Re(VI), which is subsequently disproportionated to Re(IV) and Re(VII). Effective photocatalytic reduction/removal of Re(VII)/Tc(VII) is performed on the material, which may be considered a potential and convenient strategy for technetium decontamination and extraction in a strongly acidic aqueous solution.

中文翻译：

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强酸性水溶液中高铼酸盐和高锝酸盐的光催化还原


高锝酸（ ⁹⁹ TcO ₄ ^– ）是一种具有生理毒性的放射性阴离子，由于其在环境污染修复中的高流动性而备受关注。尽管可溶性氧阴离子可以光还原为微溶性TcO ₂ ·nH ₂ O，但其从强酸性水溶液中的有效去除仍然是一个挑战。在这里，我们发现低结晶氮掺杂二氧化钛（N-TiO ₂ , 0.6 g L ^–1 ）可以有效地吸收高铼酸（ReO ₄ < b8> ， 10 mg·L ^–1 ，TcO 的非放射性替代品 ₄ ^– ) 在 pH 值模拟阳光照射下 360 分钟内具有 50.8% 1.0，但 P25 和锐钛矿不能。 N-TiO ₂ 中微量氮掺杂形成的氮活性中心可以促进光生载流子的分离和转移。 N-TiO ₂ 的正价带值略高于P25和锐钛矿，这意味着光生空穴具有更强的氧化性。这些空穴参与甲酸氧化过程中强还原性 ^• CO ₂ ^– 自由基的形成。活性自由基将 ReO ₄ ^– 转化为 Re(VI)，随后歧化为 Re(IV) 和 Re(VII)。对该材料进行了有效的光催化还原/去除Re(VII)/Tc(VII)，这可能被认为是强酸性水溶液中锝净化和萃取的潜在且方便的策略。