| 合成时间对钛酸盐纳米材料的影响及其吸附水中铅的性能研究 |
| 摘要点击 2542 全文点击 971 投稿时间：2015-07-21 修订日期：2015-09-12 |
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| 中文关键词 钛酸盐纳米材料 合成时间 铅 吸附 再生 |
| 英文关键词 titanate nanomaterials reaction time lead adsorption regeneration |
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| 中文摘要 |
| 以TiO2(ST-01)和NaOH为原料,采用碱性水热法通过调节反应时间合成不同形貌的钛酸盐纳米材料(TNs),利用XRD、 SEM、 BET对材料的形貌、 结构、 比表面积和化学组成等物化性能进行表征,并通过其对水中Pb(Ⅱ)的静态吸附实验,考察材料对Pb(Ⅱ)的吸附性能和吸附规律. 结果表明,12~72 h合成的TNs均为纯净的单斜相钛酸盐,比表面积为243.05~286.20 m2 ·g-1; 12~36 h合成的TNs主要为片状结构,48 h以上的TNs为线状结构. TNs-12、 TNs-24、 TNs-36、 TNs-48、 TNs-60和TNs-72对Pb(Ⅱ)的吸附量分别为479.40、 504.12、 482.00、 388.10、 364.60和399.00 mg ·g-1,片状的TNs对Pb(Ⅱ)具有比线状更高的吸附能力,其中以TNs-24对Pb(Ⅱ)的吸附量最高. TNs-24对Pb(Ⅱ)的吸附结果符合准二级动力学模型和Langmuir模型,吸附平衡时间为120 min; TNs对Pb(Ⅱ)的吸附为放热过程,低温或室温便有较高的吸附量; 最佳吸附pH为5.0; 当pH为1.0时,TNs-24的解析率可达到99.00%; 再生的TNs对Pb(Ⅱ)循环吸附6次的去除率仍可达到97%以上,可见TNs可很好地去除水中重金属Pb(Ⅱ). 因此,最佳合成时间可控制在12~24 h; 当溶液中存在共存Cd(Ⅱ)或Ni(Ⅱ)时,TNs-24对Pb(Ⅱ)的平衡吸附量及去除率均有所下降; 吸附机制主要是Pb(Ⅱ)与TNs层间的H+和Na+发生离子交换作用. |
| 英文摘要 |
| Titanate nanomaterials (TNs) were synthesized via a simple hydrothermal method using TiO2 (ST-01) and NaOH as the raw materials, and presented different morphologies by adjusting the reaction time. The physico-chemical properties of the as-prepared TNs, such as morphology, structure, surface area, and chemical composition were characterized by XRD, SEM and BET. The adsorption capability and rules of Pb(Ⅱ) in aqueous solutions were tested in the static system. The results showed that the TNs prepared with 12-72 h reaction time were pure monoclinic phase titanate and their specific surface areas were in the range from 243.05 m2 ·g-1 to 286.20 m2 ·g-1. TNs with reaction time between 12-36 h mainly showed sheet structure, and those with reaction time higher than 48 h showed linear structure. The adsorption capacity of Pb(Ⅱ) by TNs-12, TNs-24, TNs-36, TNs-48, TNs-60 and TNs-72 was 479.40, 504.12, 482.00, 388.10, 364.60 and 399.00 mg ·g-1, respectively. The sheet TNs had a better adsorption capacity than the linear TNs. TNs-24 had the highest adsorbing capacity. The adsorption kinetics of Pb(Ⅱ) by TNs-24 followed the pseudo-second-order model, and the equilibrium data was best fitted with the Langmuir isotherm model. The equilibrium adsorption time of TNs-24 was 120 min, and the adsorption was an exothermic process, with a high adsorption capacity at low temperature or room temperature; the optimal adsorption pH was 5.0. When pH was 1.0, the desorption rate of TNs-24 could reach 99.00%, and the removal efficiency of Pb(Ⅱ) by regenerated TNs was still more than 97% after six times of usage. Therefore, TNs could efficiently remove Pb(Ⅱ) in aqueous solutions, and the optimal reaction time should be controlled to 12-24 h. When Cd (Ⅱ) or Ni(Ⅱ) existed in the solution, the equilibrium adsorption capacity and removal rate of TNs-24 were decreased.The adsorption mechanism was mainly ion-exchanged between Pb(Ⅱ) and H+/Na+in TNs. |
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