Evaluation of lanthanide sorption and their coordination mechanism by EXAFS measurement using novel hybrid adsorbent
Evaluation of lanthanide sorption and their coordination mechanism by EXAFS measurement using novel hybrid adsorbent
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DOI：
10.1016/j.cej.2013.04.015
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发表时间：
2013-06-01
影响因子：
15.1
通讯作者：
Yaita, Tsuyoshi
中科院分区：
文献类型：
--
作者：
Awual, Md Rabiul;Kobayashi, Tohru;Yaita, Tsuyoshi
研究了新型复合吸附剂（HA）对废水中痕量稀土元素（Nd（III）、Eu（III）和Yb（III））的吸附和回收。通过将N-辛基-N-甲苯基-1，10-菲咯啉-2-羧酸酯功能性固定到大的笼状孔介孔硅胶整体柱中制备HA。该吸附剂稳定性好，对镧系离子的吸附和回收均以络合机理进行。通过XAFS光谱研究了pH值、离子选择性和镧系离子配位对反应的影响。稀土离子的吸附符合Langmuir吸附等温式，最大吸附容量分别为176.06、163.13和161.81 mg/g。镧系元素的吸附不受钠、钾、钙、镁、氯、硫酸根和硝酸根离子的单价和二价的存在的影响，这是由于与三价镧系元素形成稳定络合的强烈倾向。铝离子的三价特性使其对镧系离子的吸附受到强烈的竞争，在没有铝离子干扰的情况下，铝离子对镧系离子的吸附量大于其对镧系离子吸附量的一半。EXAFS数据表明，HA的O和N给体原子与镧系离子形成了稳定的配合物。然而，O施主原子的键距比N施主原子短。吸附的镧系元素离子用反萃剂洗脱，并将吸附剂再生为初始形式，用于用水冲洗后的后续吸附操作。结果表明，HA在从废水中选择性吸附和回收镧系离子方面具有广阔的应用前景。(c)2013爱思唯尔有限公司版权所有。
This study was investigated the trace lanthanide (Nd(III), Eu(III) and Yb(III)) sorption and recovery from wastewater streams by novel hybrid adsorbent (HA). The HA was prepared through functional immobilization of N-octyl-N-tolyl-1,10-phenanthroline-2-carboxaide into large and cage-pored mesoporous silica monolith. The adsorbent was stable and easy to adsorb and recover of lanthanide ions by complexation mechanism. The experiments were investigated to determine the effects pH, ions selectivity and lanthanide ions coordination by XAFS spectra. The lanthanide sorption were well fitted the Langmuir sorption isotherm model and indicated the maximum sorption capacities were 176.06, 163.13, and 161.81 mg/g for Yb(III), Eu(III) and Nd(III), respectively. The lanthanide sorption was not affected by the presence of monovalent and divalent of sodium, potassium, calcium, magnesium, chloride, sulfate and nitrate ions due to strong tendency to form stable complexation with trivalent lanthanide. However, aluminum was strongly competed of lanthanide ions sorption due to trivalent characteristic and\ lanthanide sorption was greater than half of the sorption capacity without Al3+ interfering. The EXAFS data revealed that O and N donor atoms of the HA were strongly coordinated to lanthanide ions to form stable complexes. However, the bond distance of O donor atoms was shorter than N donor atoms. The adsorbed lanthanide ions were eluted with stripping agents and the adsorbent was regenerated into initial form for subsequent sorption operations after rinsing with water. The results suggested that the HA may find promising applications for selective sorption and recovery of lanthanide ions from wastewater effluents. (c) 2013 Elsevier B.V. All rights reserved.