Absorption of Cu(II) in layered diaminoalkyl- and monoaminoalkyl-polysilsesquioxane
Absorption of Cu(II) in layered diaminoalkyl- and monoaminoalkyl-polysilsesquioxane
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DOI：
10.1016/j.polymer.2017.11.011
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发表时间：
2017-12
期刊：
影响因子：
4.6
通讯作者：
T. Takagi;I. Kawamura;Y. Oumi;Yohei Miwa;H. Yoshitake
中科院分区：
文献类型：
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作者：
T. Takagi;I. Kawamura;Y. Oumi;Yohei Miwa;H. Yoshitake
使用链烷酸合成了含有两种氨基烷基的层状聚倍半硅氧烷。我们进行这种合成的目的是增加聚合物固体中吸收位点对被吸收物的暴露，而不牺牲其高密度的位点。也就是说，该方法旨在削弱胺位点周围抑制水性阳离子污染物扩散的相互作用。液体前体中 3-氨基丙基三甲氧基硅烷（AP 硅烷）和 N-（氨基乙基）-3-氨基丙基三甲氧基硅烷（AeAP 硅烷）的混合比 x:y 与固体中 AP 和 AeAP 基团的混合比非常吻合， [(C13H27COOH)x(C12H23CH(COOH)CH2COOH)y(NH2C3H6)x(NH2C2H4NHC3H6)ySi10O15]或[(MAS)x(C12SA)y(AP)x(AeAP)ySi10O1.5]n(x+y= 10)。当 x:y 比率高于 2: 8 时，获得了良好的层状结构。 FT-IR 光谱表明，增加 x:y 比率会增强由于氢键合的 –COOH 和解离的 –COO- 导致的谱带，表明 x:y 的羧基和胺基周围的水分子插入增加。在 13 C CP-MAS NMR 中，由于羧酸根碳而导致的未解析峰在 x:y= 4: 6 和 2: 8 处消失，表明在这些混合比下羧酸根可能由于水合而被分离。此外，还观察到由于离子化的羧酸盐而导致的峰的连续增长。通过 Langmuir 方程分析可知，当 x:y=4:6 时，吸收的 Cu(II) 水溶液的量特别多。相比之下，Cu(II) 的 ESR 光谱与 x:y 比率无关，表明当 x:y= 4: 6 时，吸收位点的可及性得到简单改善。这种混合比可能为暴露含水 Cu(II) 的吸收位点提供了特别有效的结构。
Lamellar polysilsesquioxane containing two kinds of aminoalkyl groups were synthesized using alkanoic acids. Our intension with this synthesis was to increase the exposure to the absorbate of the absorption sites in the polymer solid without sacrificing its high density of sites. That is, this method is designed to weaken the interactions around the amine sites that inhibit diffusion of the aqueous cation pollutants. The mixing ratio,x:y, of 3-aminopropyltrimethoxysilane (AP silane) and N-(aminoethyl)-3-aminopropyltrimethoxysilane (AeAP silane) in the liquid precursor agrees well with that of the AP and AeAP groups in the solid, [(C13H27COOH)x(C12H23CH(COOH)CH2COOH)y(NH2C3H6)x(NH2C2H4NHC3H6)ySi10O15]nor [(MAS)x(C12SA)y(AP)x(AeAP)ySi10O1.5]n(x+y= 10). A good lamellar structure was obtained withx:yratio higher than 2: 8. FT-IR spectroscopy reveals that increasing thex:yratio enhances the bands due to hydrogen-bonded –COOH and dissociated –COO-, suggesting an increase in water molecule insertion around the carboxyl and amine groups withx:y. In13C CP-MAS NMR, unresolved peaks due to carboxylate carbons disappear atx:y= 4: 6 and 2: 8, suggesting that carboxylate is isolated at these mixing ratios probably due to hydration. In addition, continuous growth of the peak due to ionized carboxylate is observed. The amount of absorbed aqueous Cu(II) is particularly large whenx:y= 4: 6, which is revealed by analysis with the Langmuir equation. In contrast, the ESR spectrum of Cu(II) is independent on thex:yratio, suggesting the accessibility of the absorption sites is simply improved whenx:y= 4: 6. It is likely that this mixing ratio provides a particularly effective structure for exposing the absorption sites of aqueous Cu(II).