Investigation and simulation of the transport of gas containing mercury in microporous silica membranes

Ji, Guozhao; George, Anthe; Skoulou, Vicky; Reed, Graham; Millan, Marcos; Hooman, Kamel; Bhatia, Suresh K.; Diniz da Costa, João C.

Abstract

This work investigates the effect of condensable Hg vapour on the transport of N2 gas across cobalt oxide silica (CoOxSi) membranes. Experimental results suggest that Hg significantly affects N2 permeation at 100 and 200°C, though this effect is negligible at 300°C. This effect was found to have a correlation with Hg adsorption on CoOxSi xerogels. In order to understand the Hg effect in the transport phenomena of N2 permeation, the oscillator model was used to model gas transport through pores with different sizes. By including effective medium theory (EMT), the oscillator model fitted well the experimental results and gave good prediction of mass transfer in ultra-microporous materials with a tri-modal pore size distribution, such as silica membranes. It is postulated that Hg seeks lower level potentials in micro-pores, and therefore Hg molecules tend to block small pores (2.5-4Å from 2.9Å), or reduce the average pore size of larger pores (6.7-7.8Å and 12-14Å). Although N2 permeation decreased with the presence of Hg, it did not decrease when the Hg load was increased by a factor of ten; this strongly suggests the adsorption of Hg molecules in the smaller pores (2.5-4.0Å), or along the pore wall for the larger pore ranges (6.7-7.8Å and 12-14Å).

Citation

Ji, G., George, A., Skoulou, V., Reed, G., Millan, M., Hooman, K., …Diniz da Costa, J. C. (2018). Investigation and simulation of the transport of gas containing mercury in microporous silica membranes. Chemical engineering science, 190, 286-296. https://doi.org/10.1016/j.ces.2018.06.006

• Journal Article Type: Article
• Acceptance Date: Jun 1, 2018
• Online Publication Date: Jun 2, 2018
• Publication Date: Nov 23, 2018
• Deposit Date: Jun 13, 2018
• Publicly Available Date: Jun 3, 2019
• Print ISSN: 0009-2509
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 190
• Pages: 286-296
• DOI: https://doi.org/10.1016/j.ces.2018.06.006
• Keywords: Silica membrane; Mercury adsorption; Micropore transport; Effective media theory; Oscillator model
• Public URL: https://hull-repository.worktribe.com/output/729911
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0009250918303683