Effective removal of fluoride by porous MgO nanoplates and its adsorption mechanism
Effective removal of fluoride by porous MgO nanoplates and its adsorption mechanism
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多孔MgO纳米板有效去除氟化物及其吸附机理
DOI：
10.1016/j.jallcom.2016.03.118
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发表时间：
2016-08-05
影响因子：
6.2
通讯作者：
Liu, Jin-Huai
中科院分区：
文献类型：
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作者：
Jin, Zhen;Jia, Yong;Liu, Jin-Huai
采用一种简单、经济的前驱体煅烧方法成功地合成了多孔MgO纳米板。通过x射线衍射、扫描电镜、透射电镜和布鲁诺尔-埃米特-泰勒测量对制备的多孔MgO纳米板进行了表征。研究了多孔MgO纳米板的除氟性能。吸附剂对氟的吸附速度非常快，吸附动力学可拟合为准二阶模型。吸附等温线可以很好地拟合Freundlich模型，在pH为7时吸附量大于185.5 mg/g。此外，多孔MgO纳米板可以在2 ~ 10的pH范围内有效去除水中的氟化物，有利于实际应用。还研究了共存阴离子对除氟的影响。结果表明，碳酸盐、碳酸氢盐和磷酸盐的存在会影响氟的吸附性能。通过FTIR和XPS分析探讨了氟的吸附机理。结果表明，羟基和表面碳酸盐均能与氟离子交换，揭示了羟基与碳酸盐的共交换机制。此外，制备的多孔MgO纳米板具有良好的稳定性，在吸附实验中只有不到0.18%的吸附剂被溶解。结果表明，制备的多孔MgO纳米板可作为除氟的潜在候选材料。(C) 2016 Elsevier B.V.版权所有
Porous MgO nanoplates were successfully synthesized through a facile and cost-effective precursor calcination method. The as-prepared porous MgO nanoplates were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Brunauer-Emmett-Teller measurements. The fluoride removal performance of the porous MgO nanoplates has been investigated. The fluoride adsorption rate of the absorbent was very fast, and the adsorption kinetics could be fitted into a pseudo-second-order model. The adsorption isotherm can be well fitted in Freundlich model, while the adsorption capacity was over 185.5 mg/g at pH 7. Furthermore, the porous MgO nanoplates can efficiently remove fluoride from water in a wide pH range of 2-10, which is favorable for practical application. The effect of co-existing anions on fluoride removal also has been investigated. The result indicated that the existence of carbonate, bicarbonate and phosphate can influenced the fluoride adsorption performance. Furthermore, the fluoride adsorption mechanism was investigated by the FTIR and XPS analysis. The results show that both the hydroxyl and surface carbonates can exchange with fluoride ions, revealing a hydroxyl and carbonate co-exchange mechanism. Moreover, the as-prepared porous MgO nanoplates is quite stable, only less than 0.18% of the absorbent was dissolved during the adsorption experiment. The results indicated that the as-prepared porous MgO nanoplates can be used as a potential suitable candidate for fluoride removal. (C) 2016 Elsevier B.V. All rights reserved.