Peter Jr Leszczynski, Siamak Lashkari, Boguslaw Kruczek
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引用次数: 0
Abstract
The time-lag method is commonly used to determine membrane permeability, diffusivity and solubility in a single gas permeation experiment in a constant volume system. An unwritten assumption on which this method relies is that there is no resistance to gas accumulation in the downstream receiver of the system. However, this is not the case, even with the specially designed receiver used in this study when, in addition to tubing, the receiver utilizes an additional accumulation tank. The resistance to gas accumulation originates from a finite diffusivity (Knudsen diffusion) of gases in tubing, which are magnified by "resistance-free" accumulation tank(s). As a result of the resistance to gas accumulation, the time lag of the membrane is underestimated, which leads to an overestimation of gas diffusivity in the membrane. The experimentally predicted resistances in different configurations of the receiver, expressed by the difference in the time lag at two different receiver locations, were several times greater than the theoretically predicted values. A high molecular PPO membrane was used to demonstrate this effect. The time lags measured at different locations differed by as much as 30%. The diffusivity of nitrogen in a PPO of 4.04 × 10-12 m2/s determined at the optimum configuration of the receiver is at least 50% lower than the literature-reported values.
MembranesChemical Engineering-Filtration and Separation
CiteScore
6.10
自引率
16.70%
发文量
1071
审稿时长
11 weeks
期刊介绍:
Membranes (ISSN 2077-0375) is an international, peer-reviewed open access journal of separation science and technology. It publishes reviews, research articles, communications and technical notes. Our aim is to encourage scientists to publish their experimental and theoretical results in as much detail as possible. There is no restriction on the length of the papers. Full experimental and/or methodical details must be provided.