Fan Gong-duan, Chen Li-ru, Lin Ru-jing, Lin Qian, Su Zhao-yue, Lin Xiu-yong
Huan Jing Ke Xue. 2016 Feb 15;37(2):668-79.
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 x g(-1) to 286.20 m2 x 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 x 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.
以TiO₂（ST - 01）和NaOH为原料，通过简单的水热法合成了钛酸盐纳米材料（TNs），并通过调整反应时间呈现出不同的形貌。采用XRD、SEM和BET对所制备的TNs的物理化学性质，如形貌、结构、比表面积和化学成分进行了表征。在静态体系中测试了TNs对水溶液中Pb(II)的吸附能力和规律。结果表明，反应时间为12 - 72 h制备的TNs为纯单斜相钛酸盐，其比表面积在243.05 m²·g⁻¹至286.20 m²·g⁻¹范围内。反应时间在12 - 36 h的TNs主要呈现片状结构，反应时间高于48 h的TNs呈现线状结构。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TNs的吸附能力优于线状TNs。TNs - 24具有最高的吸附容量。TNs - 24对Pb(II)的吸附动力学符合准二级模型，平衡数据最符合Langmuir等温模型。TNs - 24的平衡吸附时间为120 min，吸附为放热过程，在低温或室温下具有较高的吸附容量；最佳吸附pH为5.0。当pH为1.0时，TNs - 24的解吸率可达99.00%，再生后的TNs使用六次后对Pb(II)的去除效率仍超过97%。因此，TNs能够高效去除水溶液中的Pb(II)，最佳反应时间应控制在12 - 24 h。当溶液中存在Cd(II)或Ni(II)时，TNs - 24的平衡吸附容量和去除率降低。吸附机理主要是Pb(II)与TNs中的H⁺/Na⁺之间的离子交换。
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