Glass membranes for purification of aggressive gases Part II. Adsorption measurements and diffusion coefficient estimations
Glass membranes for purification of aggressive gases Part II. Adsorption measurements and diffusion coefficient estimations
复制标题
用于净化腐蚀性气体的玻璃膜第二部分。
DOI：
10.1016/j.memsci.2005.03.057
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
May‐Britt Hägg
中科院分区：
文献类型：
--
作者：
A. Lindbråthen;May‐Britt Hägg
本文第一部分对几种玻璃膜在腐蚀性气体环境中的耐久性和分离性能进行了评价。表面改性玻璃膜（用（十六氟-1,1,2,2-四氢癸基）二甲基氯硅烷（Pf-C10）改性）在稳定性、渗透性和选择性方面被证明是最佳选择。为了更好地理解气体分离发生的控制机制，选择表面流动，吸附和扩散系数进行了更密切的研究。本文报道了Cl2， HCl, R22 (CHF2Cl), He, H2, N2， CO, O2, Xe， sf6和CO2的气体。重点关注的温度和压力范围分别为1-4bar和30-45°C，因为这些范围被认为是最有趣的，关于通过Pt-C10表面改性玻璃膜的运输可能发生的变化。本文还讨论了相对于Knudsen流的选择性表面流的程度。当绘制吸附系数与SSF度的关系时，似乎有两种不同的模式：Cl2， HCl和R22（都含有氯并且具有高临界温度）用极高的吸附系数来描述，而其他气体则最好用指数拟合来描述。在相同压力下，cl2和HCl的吸附热与冷凝热相当。假设这些气体的吸附对应于文献中描述的拟议的“滑动液体层”流动，而其他气体的指数行为对应于“点到点跳跃”或二维气体流动。
In the article Part I of this work durability and separation properties for several types of glass membranes in aggressive gas environment have been evaluated. A surface modified glass membrane (modified with (heptadecafluoro-1,1,2,2-tetrahydrodecyl) dimethyl chlorosilane, Pf-C10), proved to be the best choice with respect to stability, permeability and selectivity. For a better understanding of the gas separation taking place according to the governing mechanism, selective surface flow, the sorption and diffusion coefficients were investigated more closely. This is reported in the current paper for the gases Cl2, HCl, R22 (CHF2Cl), He, H2, N2, CO, O2, Xe, SF6and CO2. Temperature and pressure range focused on were 1–4bar and 30–45°C, respectively, as these ranges were judged to be most interesting with respect to possible changes in the transport through the Pt-C10 surface modified glass membrane. The degree of selective surface flow, SSF, relative to the Knudsen flow is also discussed in this work. When plotting the sorption coefficient versus degree of SSF, there seems to be two distinct patterns: The Cl2, HCl and R22 (all containing chlorine and have high critical temperatures) are described by exceptionally high sorption coefficients, while the other gases are best described by an exponential fit. The heat of adsorption for Cl2and HCl was found to be comparable to the heat of condensation at the same pressure. It was assumed that the adsorption of these gases corresponds to the proposed “sliding liquid layer” flow described in the literature, while the exponential behaviour of the other gases correspond to the “site to site hopping” or 2D gas flow.