Removal of hydrophilic ionic liquids from aqueous solutions by adsorption onto high surface area oxygenated carbonaceous material
Removal of hydrophilic ionic liquids from aqueous solutions by adsorption onto high surface area oxygenated carbonaceous material
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DOI：
10.1016/j.cej.2014.07.020
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发表时间：
2014-11
影响因子：
15.1
通讯作者：
X. Qi;Luyang Li;Yu Wang;Nian Liu;R. Smith
中科院分区：
文献类型：
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作者：
X. Qi;Luyang Li;Yu Wang;Nian Liu;R. Smith
通过纤维素的水热碳化和KOH的化学活化，制备了一种具有大比表面积和高含氧基团的碳质材料，目的是开发一种亲水性离子液体的吸附剂。将所制备的炭质材料(a-CM)用于研究具有代表性的咪唑基亲水离子液体的吸附性能，其吸附容量几乎是商业活性碳(CAC)吸附剂的3倍。α-CM吸附剂对亲水性离子液体的大吸附容量归因于其表面含氧基团(C-OH、单键C双键和-COOH)。考察了离子液体化学结构对CM吸附的影响，发现吸附容量随阴离子疏水性的增加和咪唑阳离子的烷基链长的增加而增大。亲水性离子液体较好地吸附在高氧型EDA-CM吸附剂上，而疏水性离子液体较好地吸附在CAC吸附剂上。所制备的吸附剂可以用Zeta电位得出的零电荷点(PHPZC)来表征。这项工作的结果表明，通过根据离子液体的化学特性调整吸附剂的表面化学结构，可以有效地从含水废水中去除离子液体。
A carbonaceous material having a large surface area and high number of oxygenated groups was prepared by hydrothermal carbonization of cellulose and chemical activation with KOH with the goal to develop an adsorbent for hydrophilic ionic liquids. The as-prepared carbonaceous material (a-CM) was used to study the adsorption of representative imidazolium-based hydrophilic ionic liquids and exhibited adsorption capacity that was almost three times higher than that of commercial activated carbon (CAC) adsorbent. The large adsorption capacity ofa-CM adsorbent for hydrophilic ionic liquids is attributed to its polar oxygenated surface groups (C–OH, single bondCdouble bondO and –COOH). The effect of ionic liquid chemical structure ona-CM adsorption was investigated in which it was found that adsorption capacity increased with increasing hydrophobicity of the anions and increasing alkyl chain length of the imidazolium cation. Hydrophilic ionic liquids were favorably adsorbed onto the highly-oxygenateda-CM adsorbent whereas hydrophobic ionic liquids were favorably adsorbed onto CAC adsorbent. The as-prepared adsorbent could be characterized by the point of zero charge (pHPZC) derived from zeta potential. The results of this work demonstrate that ionic liquids can be efficiently removed from aqueous wastewater by tailoring adsorbent surface chemistry to the chemical characteristics of the ionic liquid.