Removal of phosphate from water by lanthanum-modified zeolites obtained from fly ash
Removal of phosphate from water by lanthanum-modified zeolites obtained from fly ash
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DOI：
10.1016/j.jcis.2017.11.003
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发表时间：
2018-03-01
影响因子：
9.9
通讯作者：
Franus, Wojciech
中科院分区：
文献类型：
--
作者：
Goscianska, Joanna;Ptaszkowska-Koniarz, Magdalena;Franus, Wojciech
研究了用新型低成本合成沸石去除水溶液中的磷酸盐的可能性和效果。用X射线衍射法、低温氮气吸附和扫描电子显微镜等技术对沸石的物化性质进行了表征。结果表明，La优先分布在沸石分子筛的孔道和笼子中，这与离子交换改性方法有关。La离子的引入导致了比表面积的减小，这主要是由于微孔面积的减少和孔体积的减小。这项研究的关键要素是一系列从水溶液中吸附磷酸盐的测试。吸附过程的效率与吸附物浓度、溶液pH和温度有关。比较了由飞灰制得的沸石(La-P1、La-A)与天然沸石-斜发沸石(La-CLP)对磷酸盐的吸附能力。吸附容量分别为La-P_1-58.2 mg/g、La-A-44.0 mg/g和La-CLP-24.6 mg/g，符合Langmuir等温吸附模型。在25~60℃温度范围内，所有样品对磷酸盐的吸附容量都随着温度的升高而增加。热力学参数AH和AG的值表明吸附是自发的和吸热的。(C)2017 Elsevier Inc.保留所有权利。
The possibility and effectiveness of removal of phosphate from aqueous solutions with the use of new low-cost synthetic zeolites obtained from fly ash and modified with lanthanum, was studied. Physicochemical properties of the zeolites were characterized by different techniques such as X-ray diffraction, low-temperature nitrogen sorption and scanning electron microscopy. It has been established that lanthanum is preferentially located in the zeolites channels and cages, which is related to the ion exchange method of modification. Introduction of lanthanum cations leads to a reduction in BET surface area, mainly due to a decrease in the area of micropores and reduction in the pore volume. The key element of the study was a series of tests of phosphate adsorption from aqueous solutions. The efficiency of adsorption process was found to depend on the concentration of adsorbate, pH of its solution and temperature. The sorption capacity of zeolites obtained from fly ashes (La-P1, La-A) towards phosphate was compared with that of a natural zeolite - clinoptilolite, modified with lanthanum (La-CLP). The sorption capacities of the particular samples were as follows: La-P1 - 58.2 mg/g, La-A - 44.0 mg/g and La-CLP - 24.6 mg/g. The experimental data were well fitted by the Langmuir isotherm model. The sorption capacities of all samples towards phosphate increased with temperature increasing from 25 to 60 degrees C. The values of the thermodynamic parameters AH and AG revealed that the adsorption was spontaneous and endothermic. (C) 2017 Elsevier Inc. All rights reserved.