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Synchronous Moderate Oxidation and Adsorption on the Surface of γ-MnO2 for Efficient Iodide Removal from Water
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2022-06-23 , DOI: 10.1021/acs.est.2c01682
Nan Wang 1 , Gong Zhang 1 , Ruoxi Xiong 1 , Ruiping Liu 1 , Huijuan Liu 1 , Jiuhui Qu 1
Affiliation  

Long-term exposure to excessive iodine via drinking water presents health risks. Moderate oxidation of iodide (I) to iodine (I2) has a better iodine removal effect than excessive oxidation to iodate (IO3). This study combines computational and experimental methods to construct a heterogeneous interface with synchronous I moderate oxidation and I2 adsorption to increase the total iodine removal. Compared to other forms of crystal manganese dioxide (MnO2), theoretical calculations predict that MnO2 with a γ-crystal structure has the lowest adsorption energy, that is, −1.20 eV, and a slight overlap between the conduction and valence bands, which favors electron transfer between I and Mn(IV) and I2 adsorption. Thus, γ-type MnO2 was designed by adjusting the precursor Mn sources and hydrothermal reaction conditions. The liquid chromatography–inductively coupled plasma–mass spectrometry and high-performance liquid chromatography confirmed that the total iodine concentration in water decreased from 173.7 to 36.3 μg/L after 2 h, with 200 mg/L γ-MnO2 dosage lower than the national standard of 0.1 mg/L. A minute proportion of I in water was converted to IO3 (approximately 1.1 μg/L). The current I adsorbent performed better than previously reported ones. During iodine removal, most of the I migrated from water to the surface of γ-MnO2, and the ratio of I to I2 was determined to be 1:0.6 by X-ray photoelectron spectroscopy. This study evaluates iodine species transformation and an optimum strategy for heterogeneous interface design; it is promising for treating high-iodine groundwater.

中文翻译:

γ-MnO2 表面同步适度氧化和吸附,有效去除水中的碘化物

长期通过饮用水摄入过量碘会带来健康风险。碘化物(I -)适度氧化成碘(I 2 )比过度氧化成碘酸盐(IO 3 - )具有更好的除碘效果。本研究将计算和实验方法相结合,构建了一个具有同步 I -适度氧化和 I 2吸附的非均相界面,以提高总碘去除率。与其他形式的晶体二氧化锰(MnO 2)相比,理论计算预测 MnO 2γ-晶体结构的吸附能最低,即-1.20 eV,导带和价带之间有轻微的重叠,有利于I-和Mn(IV)之间的电子转移和I 2吸附。因此,通过调整前驱体Mn源和水热反应条件设计了γ型MnO 2 。液相色谱-电感耦合等离子体-质谱和高效液相色谱证实,2 h后水中总碘浓度由173.7降至36.3 μg/L,γ-MnO 2用量低于国家标准200 mg/L标准为 0.1 毫克/升。一小部分 I -在水中被转化为 IO 3 -(约 1.1 微克/升)。目前的 I -吸附剂比以前报道的表现更好。在除碘过程中,大部分I -从水中迁移到γ-MnO 2表面,通过X射线光电子能谱测定I -与I 2的比例为1:0.6。本研究评估了碘物质转化和异质界面设计的最佳策略;有望用于处理高碘地下水。
更新日期:2022-06-23
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