Organic-Inorganic Hybrid Membranes: Solving the Trade-off Phenomenon Between Permeation Flux and Selectivity in Pervaporation
Organic-Inorganic Hybrid Membranes: Solving the Trade-off Phenomenon Between Permeation Flux and Selectivity in Pervaporation
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DOI：
10.1021/ie8016626
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发表时间：
2009-04-15
影响因子：
4.2
通讯作者：
Olley, Robert H.
中科院分区：
文献类型：
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作者：
Kariduraganavar, Mahadevappa Y.;Varghese, Jolly G.;Olley, Robert H.
为了解决渗透汽化膜的渗透通量和选择性之间存在的折衷现象，采用溶液法制备了壳聚糖/TiO 2有机-无机杂化膜。采用傅里叶变换红外光谱（FTIR）、广角X射线衍射（WAXD）、扫描电子显微镜（SEM）和热重分析（TGA）对所得杂化膜进行了表征。与纯壳聚糖膜相比，杂化膜具有较高的热稳定性和较低的结晶度。测试了这些膜在30-50 ℃温度范围内通过渗透蒸发分离水-异丙醇混合物的能力。实验结果表明，通量和选择性的同时增加，在膜中的TiO 2含量。当TiO 2的质量分数为40%时，壳聚糖膜的渗透通量从3.06 × 10 - 2kg/（m2·h）增加到12.17 × 10 - 2kg/（m2·h），分离因子从509增加到94984。总通量和水通量被发现是几乎重叠的，特别是对于杂化膜，这表明这些膜可以有效地用于打破水-异丙醇混合物的共沸点。从温度依赖的扩散和渗透值，阿克里尼乌斯激活参数估计。水渗透的活化能值（E-pw）显着低于异丙醇渗透的活化能值（E-pIPA），这表明所开发的膜对水-异丙醇体系具有更高的分离效率。在所有的膜中观察到负的吸附热（Δ Hs）值，表明朗缪尔吸附模式是占主导地位的。
To solve the trade-off phenomenon existing between permeation flux and selectivity of membranes in pervaporation, organic-inorganic hybrid membranes composed of chitosan and TiO2 were prepared using a solution technique. The resulting hybrid membranes were characterized by Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Compared to pure chitosan membrane, the hybrid membranes exhibited high thermal stability and low crystallinity. These membranes were tested for their ability to separate water-isopropanol mixtures by pervaporation in the temperature range of 30-50 degrees C. The experimental results demonstrated that both flux and selectivity increased simultaneously with increasing TiO2 content in the membrane. The permeation flux of pure chitosan membrane increased dramatically from 3.06 to 12.17 x 10(-2) kg/(m(2) h) when 40 mass % of TiO2 was incorporated, and correspondingly its separation factor increased from 509 to 94 984 at 30 degrees C for 5 mass % of water in the feed. The total flux and flux of water were found to be almost overlapping particularly for hybrid membranes, suggesting that these membranes could be used effectively to break the azeotropic point of water-isopropanol mixtures. From the temperature dependent diffusion and permeation values, the Arrhenius activation parameters were estimated. The activation energy values obtained for water permeation (E-pw) were significantly lower than those of isopropanol permeation (E-pIPA), suggesting that the developed membranes have higher separation efficiency for water-isopropanol systems. The negative heat of sorption (Delta Hs) values were observed in all the membranes, indicating that Langmuir's mode of sorption is predominant.