Adsorption of lead ion on amino-functionalized fly-ash-based SBA-15 mesoporous molecular sieves prepared via two-step hydrothermal method
Adsorption of lead ion on amino-functionalized fly-ash-based SBA-15 mesoporous molecular sieves prepared via two-step hydrothermal method
复制标题
DOI：
10.1016/j.micromeso.2017.06.004
复制
发表时间：
2017-11-01
影响因子：
5.2
通讯作者：
Han, Yifan
中科院分区：
文献类型：
--
作者：
Li, Ge;Wang, Baodong;Han, Yifan
以内蒙古某电厂粉煤灰为原料，采用碱两步水热法制备了SBA-15介孔分子筛。碱溶液的影响（即，NaOH），在95 ℃下加入不同量，对灰分脱硅率的影响。以Na 2SiO 3溶液为硅源，盐酸调节pH值，P123（PEO-PPO-PEO）为模板剂，在110 ℃下进行48小时的水热晶化过程，得到分子筛。以3-氨丙基三乙氧基硅烷为改性剂，甲苯为溶剂，在120 ℃下制备了氨基官能化分子筛。采用X射线衍射、透射电子显微镜、傅里叶变换红外光谱和氮气吸附等手段对所制备的SBA-15和NH 2-SBA-15分子筛进行了表征。以NH 2-SBA-15为吸附剂，考察了吸附时间、温度、pH值、铅离子初始浓度等因素对Pb 2+去除率的影响。结果表明，NH 2-SBA-15具有典型的二维六方孔结构，比表面积、平均孔径和孔体积均小于SBA-15。随着吸附时间、吸附温度和Pb 2+初始浓度的增加，Pb 2+的去除率逐渐增加。然而，当pH值增加时，效率先增加后降低。在pH值为5、Pb 2+浓度为100 mg/L、温度为30 ℃、时间为60 min时，Pb 2+的去除率最高，>98%。吸附过程符合二级动力学模型，吸附等温线符合Langmuir模型，吸附平衡量为131 mg/g。粉煤灰基SBA-15介孔分子筛吸附剂，开发和随后在本研究中的改性，表现出更好的选择性和吸附容量，并比现有的吸附剂更便宜。该筛可为工业重金属污染废水的治理提供有效的技术支持，也为粉煤灰的高效利用提供了新的途径。(C)2017爱思唯尔公司All rights reserved.
Using an alkali two-step hydrothermal method, SBA-15 mesoporous molecular sieves were prepared from fly ash used in a thermal power plant in Inner Mongolia (China). The effect of alkali solution (i.e., NaOH), added in different amounts at 95 degrees C, on the desilication rate of the ash was determined. During the 48-h hydrothermal crystallization process at 110 degrees C, sieves were obtained using Na2SiO3 solution as the silicon source, hydrochloric acid to adjust the pH value, and P123 (PEO-PPO-PEO) as a template. Amino-functionalized molecular sieves were prepared at 120 degrees C, using 3-aminopropyltriethoxysilane as a modifier and toluene as the solvent. The prepared SBA-15 and NH2-SBA-15 molecular sieves were characterized via X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and N-2 adsorption. The effects of adsorption time, temperature, pH value, and the initial concentration of lead ions (Pb2+) on the efficiency of Pb2+ removal were investigated using NH2-SBA-15 as an adsorbent. The results revealed that, like its SBA-15 counterpart, NH2-SBA-15 has a typical two-dimensional hexagonal pore structure, with lower specific surface area, average pore diameter, and pore volume compared with its SBA-15 counterpart. Furthermore, the Pb2+-removal efficiency increased gradually with increasing adsorption time, adsorption temperature, and initial concentration of Pb2+. However, when the pH value was increased, the efficiency increased initially and decreased thereafter. The maximum removal rate (>98%) after 60 min at 30 degrees C was obtained at a pH value of 5 and a Pb2+ concentration of 100 mg/L. The adsorption process of Pb2+ and the corresponding adsorption isotherm were well described by the second-order kinetics model and the Langmuir isotherm model, respectively, and an equilibrium adsorption amount of 131 mg/g was realized. The fly-ash-based SBA-15 mesoporous molecular sieve adsorbent, developed and subsequently modified in the present study, exhibited improved selectivity and adsorption capacity, and was less expensive than existing adsorbents. This sieve can provide effective technical support for control of the industrial heavy-metal-contaminated wastewater, and provides a new approach for the efficient utilization of fly ash. (C) 2017 Elsevier Inc. All rights reserved.