A covalent organic framework exhibiting amphiphilic selective adsorption toward ionic organic dyes tuned by pH value
A covalent organic framework exhibiting amphiphilic selective adsorption toward ionic organic dyes tuned by pH value
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DOI：
10.1016/j.eurpolymj.2020.109764
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发表时间：
2020-06
影响因子：
6
通讯作者：
Shihao Xu;Zhaoquan Yao;Yinghui Zhang
中科院分区：
文献类型：
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作者：
Shihao Xu;Zhaoquan Yao;Yinghui Zhang
共价有机骨架材料由于其在许多领域的潜在应用，在过去的十年中引起了人们越来越多的关注。在这里，我们报告了一个COF涉及苯并二咪唑和羟基苯基部分合成通过席夫碱缩合，以触发他们的电离响应在酸性和碱性条件下。正如预期的那样，苯并二咪唑-COF对离子型有机染料表现出pH诱导的两亲性选择性吸附，在酸性条件（pH = 3）下选择性吸附负性甲基橙子（256 mg/g），在碱性条件（pH = 11）下选择性吸附正性甲基蓝（185 mg/g）。这可能是由于苯并二咪唑环的质子化或羟基苯基单元的去质子化引起的离子染料与离子化的COF之间的静电相互作用。同时，具有均匀尺寸（1.45 nm）的COF的有序排列赋予其尺寸排除的吸附选择性。本工作为构建两亲性COFs吸附废水中的离子型有机染料分子提供了一条简便的途径。
Covalent organic frameworks (COFs) have attracted increasing interest during the past decade owing to its potential application in many fields. Herein we report a COF involving both benzodiimidazole and hydroxyphenyl moieties synthesied through Schiff base condensation, in order to trigger their ionization response both under acid and basic conditions. As expected, the benzodiimidazole-COF exhibited pH-induced amphiphilic selective adsorption toward ionic organic dyes, evidenced by selective adsorption of negative methyl orange (256 mg/g) in acidic condition (pH = 3) and positive methyl blue (185 mg/g) in basic conditions (pH = 11), respelctively. This was reasonably ascribed to the elctrostatic interaction between ionic dyes and the ionized COF induced through the protonation of benzodiimidazole ring or the deprotonation of hydroxyphenyl unit. Meanwhile, the ordered micropore of the COF with a uniform size (1.45 nm) endows it with size-excluded adsorption selectivity. This work paves a facile way to construct COFs of amphiphilic selectivity in asdorbing ionic organic dye molecules from waste water.