Size Effect of Silica Shell on Gas Uptake Kinetics in Dry Water

Abstract

Two kinds of dry water (DW) particles are prepared by mixing water and hydrophobic silica particles with nanometer or micrometer dimensions, and the two DW particles are found to have similar size distributions regardless of the size of the silica shell. The CO2 uptake kinetics of DW with nanometer (nanoshell) and micrometer shells (microshell) are measured, and both uptake rate and capacity show the obvious size effect of the silica shell. The DW with a microshell possesses a larger uptake capacity, whereas the DW with a nanoshell has a faster uptake rate. By comparing the uptake kinetics of soluble NH3 and CO2 further, we found that the microshell enhances the stability and the dispersion degree of DW and the nanoshell offers a shorter path for the transit of guest gas into the water core. Furthermore, molecular dynamics simulation is introduced to illustrate the nanosize effect of the silica shell on the initial step of the gas uptake. It is found that the concentration of gas molecules close to the silica shell is higher than that in the bulk water core. With the increase in the size of the silica shell, the amount of CO2 in the silica shell decreases, and it is easier for the gas uptake to reach steady state.

Comprehensive Review and Perspectives of CO2 Hydrate Storage in Subseafloor Saline Sediments: Formation, Stability, and Optimization Strategies

“…The formation of gas hydrate within dry water involves two consecutive steps: First, the guest gas permeates through the hydrophobic solid shell into the aqueous inner core, followed by (second) the formation of gas hydrates through interaction between the guest gas and liquid water. A detailed discussion of this gas adsorption process, including the two steps, is provided in the work by Li et al DW emerges as a promising material for capturing and storing CO 2 as clathrate hydrates . The enhanced gas adsorption within DW’s silica particle pores also accelerates the hydrate formation process. , Currently, enhancing DW’s adsorption capacity and optimizing the gas hydrate formation rate remain critical challenges for its practical application.…”

Formation Mechanism of Multipurpose Silica Nanocapsules

“…“Dry water,” a water-in-air Pickering emulsion, is a flowing powder made up of roughly 90% water but appears completely dry . This can be adapted for CO 2 capture and other gas storage. , Capsules can also be used to confine chemical reactions, such as the Diels–Alder cycloaddition . As there are essentially infinite possibilities for core–shell combinations, many more applications will emerge in the near future.…”

Methane Hydrate Nucleation within Elastic Confined Spaces: Suitable Spacing and Elasticity Can Accelerate the Nucleation

“…Most of the porous materials, however, have rigid pores or channels, which show a restraining effect on hydrate growth. Therefore, a class of elastic or flexible porous materials are considered, such as flexible MOF, covalent organic frameworks, dry water, and so on. When elastic porous materials are absorbed with gas molecules, they usually show a breathing effect like a sponge .…”