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In this paper, a model is presented to correlate and predict the swelling behavior of hydrogels in aqueous solutions of electrolytes. The model is a combination of VERS-model, “phantom network“ theory and “free-volume“ contribution. The VERS-model is used to calculate Gibbs excess energy; “phantom network“ theory to describe the elastic properties of polymer network, and “free-volume“ contribution to account for additional difference in the size of the species. To test the model, a series of N-isopropylacrylamide based hydrogels are synthesized by free radical polymerization in oxygen-free, deionized water at 25~C under nitrogen atmosphere. Then, the degree of swelling of all investigated gels as well as the partition of the solute between the gel phase and the surrounding coexisting liquid phase are measured in aqueous solution of sodium chloride. The model test demonstrates that the swelling behavior correlated and predicted by the model agrees with the experimental data within the experimental uncertainty. The phase transition appeared in the experiment, and the influences of the total mass fraction of polymerizable materials ξgel as well as the mole fraction of the crosslinking agent YCR on the swelling behavior of IPAAm-gels can also be predicted correctly. All these show the potential of such model for correlation and prediction of the swelling behavior of hydrogels in aqueous solutions of electrolytes. 相似文献
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芳烃污染空气光催化净化材料研究进展与展望 总被引:1,自引:0,他引:1
芳烃化合物是一类难降解的有毒挥发性有机物,排放到大气对生态环境有极大的危害。光催化技术作为一种高级氧化技术是未来环境净化技术的发展方向之一。然而,经典的TiO2材料对芳烃的光催化氧化,不仅活性低而且极易失活,这在很大程度上制约了光催化技术在空气净化领域的实际应用。在综述国内外研究进展的基础上,简要总结了最近几年我们在芳烃污染空气的光催化净化材料开发和性能研究方面的一些进展。研究结果显示,有众多宽带隙半导体材料对芳烃表现出比TiO2更加优异的光催化活性和活性稳定性;有些材料甚至在可见光诱导下可表现出非常高的光催化活性。此外,在反应气氛中添加少量氢气可以大幅度提高贵金属修饰TiO2对苯的光催化降解效率。这些进展充分显示出光催化技术在工业三苯废气处理和空气净化等方面的广阔应用前景。 相似文献
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In this paper, a model is presented to correlate and predict the swelling behavior of hydrogels in aqueous solutions of electrolytes. The model is a combination of VERS-model, "phantom network" theory and "free-volume" contribution. The VERS-model is used to calculate Gibbs excess energy; "phantom network" theory to describe the elastic properties of polymer network, and "free-volume" contribution to account for additional difference in the size of the species. To test the model, a series of N-isopropylacrylamide based hydrogels are synthesized by free radical polymerization in oxygen-free, deionized water at 25℃ under nitrogen atmosphere. Then, the degree of swelling of all investigated gels as well as the partition of the solute between the gel phase and the surrounding coexisting liquid phase are measured in aqueous solution of sodium chloride. The model test demonstrates that the swelling behavior correlated and predicted by the model agrees with the experimental data within the experimental uncert 相似文献
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研究了真空条件下四丁基锡(SnBu4)在Pt/HY分子筛超笼表面的接枝反应,并用元素分析、ICP、GC-MS、XRD、FTIR、TG、BET、UV-Vis等方法对产物的组成、结构和性质进行了表征。研究结果表明,SnBu4与Pt/HY分子筛表面羟基可以定量、有选择性地进行化学反应,将确定数目的SnBu3碎片接枝在分子筛的超笼中。经SnBu4改性后的Pt/HY分子筛的骨架结构没有被破坏,接枝反应发生在分子筛表面,BET比表面积和孔体积变小,表面性质发生变化。将改性后的Pt/HY分子筛应用于糠醛气相氢化反应,糠醇的选择性明显增加。 相似文献
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光催化材料在太阳能转换与环境净化方面的研究现状和发展趋势 总被引:6,自引:0,他引:6
本文简要评述了光催化材料在太阳能转化和环境净化方面应用的研究背景、现状和发展趋势。 相似文献
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