• 关键词：钛酸纳米管  水热反应  吸附容量  重金属离子  吸附选择性

• 基金项目：国家自然科学基金(No.51379010)

• 雷立
• 1. 交通运输部水运科学研究院, 北京 100088;2. 北京大学环境工程系, 水沙科学教育部重点实验室, 北京 100871

• 李学钊
• 北京大学环境工程系, 水沙科学教育部重点实验室, 北京 100871

• 晋银佳
• 华电电力科学研究院 环保技术部, 杭州 310030

• 王婷
• 北京大学环境工程系, 水沙科学教育部重点实验室, 北京 100871

• 晏友
• 交通运输部水运科学研究院, 北京 100088

• 刘文
• 北京大学环境工程系, 水沙科学教育部重点实验室, 北京 100871

• 摘要：采用温和水热法一步快速合成了钛酸盐纳米管(TNTs),并应用于对水中重金属离子Pb(Ⅱ)、Cd(Ⅱ)和Cr(Ⅲ)的吸附.通过选择纳米级锐钛矿替代P25型二氧化钛作为反应原材料,成功将水热反应时间从72 h缩短至6 h.TEM,XRD和FT-IR等表征证实了新合成材料的为管状钛酸盐结构.TNTs对3种重金属离子的吸附动力学均符合准二级动力学方程,吸附等温线均符合Langmuir模型,且对Pb(Ⅱ)、Cd(Ⅱ)和Cr(Ⅲ)的理论最大吸附量分别高达525.58、214.41和69.65 mg·g^-1.pH=5时,吸附动力学实验表明对于初始浓度分别为200、100和50 mg·L^-1的Pb(Ⅱ)、Cd(Ⅱ)和Cr(Ⅲ),在TNTs上的平衡吸附量分别为513.04、212.46和66.35 mg·g^-1,吸附性能优于传统吸附材料.合成的TNTs结构为三联的[TiO₆]八面体骨架和层间H⁺/Na⁺,其吸附机理为金属阳离子与TNTs层间Na⁺的离子交换.同时,共存离子对吸附的影响实验表明TNTs对重金属离子的吸附存在选择性,即使在较高的共存离子浓度下(10 mmol·L^-1)TNTs对目标重金属离子的吸附性能依然优异.该研究提供了一种应用钛酸纳米材料高效去除水体重金属离子的方法.

• Abstract：Titanate nanotubes (TNTs) were rapidly synthesized through a one-step facile hydrothermal method, and were used for adsorption of Pb (Ⅱ), Cd (Ⅱ) and Cr (Ⅲ) from waters. The hydrothermal reaction time was successfully reduced from 72 to 6 h by using nano-anatase instead of P25 TiO₂ as the raw material. TEM, XRD and FT-IR analysis indicated that the as-prepared TNTs were titanate with nano-tubular structure. Adsorption kinetics of the three metals by TNTs was fit well with pseudo-second-order model while Langmuir model could better describe the adsorption isotherms. In addition, the maximum adsorption capacity of Pb (Ⅱ), Cd (Ⅱ) and Cr (Ⅲ) onto TNTs calculated by Langmuir model was 525.58, 214.41 and 69.65 mg·g^-1. At pH 5, kinetics tests indicated that the equilibrium adsorption capacity of Pb (Ⅱ), Cd (Ⅱ) and Cr (Ⅲ) on TNTs was 513.04, 212.46 and 66.35 mg·g^-1 with initial metal concentration of 200, 100 and 50 mg·L^-1, respectively, which was much larger than that on other conventional adsorbents. The synthesized TNTs are composed of triple[TiO₆] octahedron as the skeleton and H⁺/Na⁺ located in the interlayers, with the primary adsorption mechanism of ion-exchange between metal cations and interlayered Na⁺. Furthermore, TNTs exhibited adsorption selectivity for heavy metal ions, as the adsorption performance was still good even at high concentration (10 mmol L^-1) of co-existing inorganic ions. This study presents a method for efficient removal heavy metals using titanate nanomaterials.

• Key words：titanate nanotubes  hydrothermal reaction  adsorption capacity  heavy metal ions  adsorption selectivity

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