Facilitated transport effect of Ag + ion exchanged halloysite nanotubes on the performance of polyet
Facilitated transport effect of Ag + ion exchanged halloysite nanotubes on the performance of polyet
复制标题
DOI：
10.1016/j.memsci.2011.06.010
复制
发表时间：
2011-09
期刊：
影响因子：
--
通讯作者：
A. Ismail;S. Hashemifard;T. Matsuura
中科院分区：
文献类型：
--
作者：
A. Ismail;S. Hashemifard;T. Matsuura
研究了Ag+离子交换埃洛石纳米管（HNTs）作为填料对非对称混合基质膜（MMM）气体分离性能的促进传递作用。本研究中使用的聚合物基质是商业聚醚酰亚胺（PEI）Ultem 1000。用N-β-（氨乙基）-γ-氨丙基三甲氧基硅烷（AEAPTMS）和硝酸银处理HNT，制备改性HNT。采用FESEM、XRD、FTIR、TGA、DSC、EDX和纯气体渗透测试对改性后的HNTs和制备的MMM进行了表征。执行了三个方案：（i）S-HNT MMM（无Ag+离子交换处理），（ii）S-Ag-HNT MMM（HNT的首先Ag+离子交换，然后甲硅烷基化），和（iii）Ag-S-HNT MMM（HNT的首先甲硅烷基化，然后Ag+离子交换）。FTIR和TGA表明硅烷化反应成功进行。XRD分析表明，Ag+离子交换对HNT的晶体结构没有影响。EDX分析表明，HNT硅烷化后的Ag+离子交换使产物中Ag+浓度大大提高。这反过来表明AEAPTMS可以成功地提高HNTs的阳离子交换容量（CEC），这导致改性HNTs中更高的Ag+离子浓度。DSC显示具有Ag+离子的MMM的玻璃化转变温度（Tg）降低。讨论了三个主要因素：（i）Ag+离子的易化传输作用，（ii）Knudsen扩散和（iii）Tg降低。通过增加填料负载量，所有因素对渗透性表现出加和性影响。所得MMM与理想形貌的接近程度顺序为：Ag-S-HNT MMM>S-Ag-HNT MMM>S-HNT MMM。Ag-S-HNT MMM在三种协议中表现出优异的性能。
This study investigated the facilitated transport effect of Ag+ion exchanged halloysite nanotubes (HNTs) as filler on the gas separation performance of asymmetric mixed matrix membranes (MMMs). The polymer matrix employed in this study was commercial polyetherimide (PEI) Ultem 1000. The modified HNTs were prepared by treating HNTs with N-β-(aminoethyl)-γ-aminopropyltrimethoxy silane (AEAPTMS) and silver nitrate. FESEM, XRD, FTIR, TGA, DSC, EDX and pure gas permeation testing were used to characterise the modified HNTs and the fabricated MMMs. Three protocols were performed: (i) S-HNT MMM (no Ag+ion exchange treatment), (ii) S-Ag-HNT MMM (first Ag+ion exchanging and then silylation of HNTs), and (iii) Ag-S-HNT MMM (first silylation and then Ag+ion exchanging of HNTs). FTIR and TGA showed that silylation occurred successfully. From XRD we found out that, the Ag+ion exchanging did not affect the HNT crystalline structure. EDX revealed that, Ag+ion exchanging after silylation of HNTs resulted in much higher concentration of Ag+ions in the Ag-S-HNT product. This in turn showed that AEAPTMS could successfully enhance the HNTs cation exchange capacity (CEC), which resulted in higher concentration of Ag+ions in the modified HNTs. DSC disclosed depression in the glass transition temperature (Tg) of MMMs possessed Ag+ions. Three major factors were discussed: (i) facilitated transport affect of Ag+ions, (ii) Knudsen diffusion and (iii) Tgdepression. By increasing the fillers loading, all of the factors exhibited an additive influence on the permeability. The order of closeness of the resultant MMMs to the ideal morphology was as follows: Ag-S-HNT MMM>S-Ag-HNT MMM>S-HNT MMM. Ag-S-HNT MMM exhibited outstanding performance among the three protocols.