Fluid-flow effects in the reactive decontamination of porous materials driven by chemical swelling or contraction

Geng, Yixing; Kamilova, Alissa; Luckins, Ellen K.

doi:10.1007/s10665-023-10283-6

Cited by 2 publications

(2 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the sharp-interface case, such a flow in the cleanser phase might be incorporated into the homogenised model using a similar analysis to that developed for an evaporation front in [11]. The effect of such a flow is investigated in [7] for the sharp-interface case, but it is not clear what the effect would be on solutions of the agent-on-walls model. Finally, we have assumed two highly idealised agent distributions in the pore space.…”

Section: Discussionmentioning

confidence: 99%

The effect of pore-scale contaminant distribution on the reactive decontamination of porous media

et al. 2023

View full text Add to dashboard Cite

A porous material that has been contaminated with a hazardous chemical agent is typically decontaminated by applying a cleanser solution to the surface and allowing the cleanser to react into the porous material, neutralising the agent. The agent and cleanser are often immiscible fluids and so, if the porous material is initially saturated with agent, a reaction front develops with the decontamination reaction occurring at this interface between the fluids. We investigate the effect of different initial agent configurations within the pore space on the decontamination process. Specifically, we compare the decontamination of a material initially saturated by the agent with the situation when, initially, the agent only coats the walls of the pores (referred to as the ‘agent-on-walls’ case). In previous work (Luckins et al., European Journal of Applied Mathematics, 31(5):782–805, 2020), we derived homogenised models for both of these decontamination scenarios, and in this paper we explore the solutions of these two models. We find that, for an identical initial volume of agent, the decontamination time is generally much faster for the agent-on-walls case compared with the initially saturated case, since the surface area on which the reaction can occur is greater. However for sufficiently deep spills of contaminant, or sufficiently slow reaction rates, decontamination in the agent-on-walls scenario can be slower. We also show that, in the limit of a dilute cleanser with a deep initial agent spill, the agent-on-walls model exhibits behaviour akin to a Stefan problem of the same form as that arising in the initially saturated model. The decontamination time is shown to decrease with both the applied cleanser concentration and the rate of the chemical reaction. However, increasing the cleanser concentration is also shown to result in lower decontamination efficiency, with an increase in the amount of cleanser chemical that is wasted.

show abstract

Section: Discussionmentioning

confidence: 99%

The effect of pore-scale contaminant distribution on the reactive decontamination of porous media

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Conservation of dirt across the interface is given by where is the normal velocity of the depositing/eroding interface. We note that, in order that there is no flow generated at the depositing interface, we assume that the dirt and liquid have the same mass density, so that the total mixture density is the same on either side of the depositing/eroding interface, while the dirt and liquid fractions can jump (see, for instance, Geng, Kamilova & Luckins 2023).…”

Section: Model Derivationmentioning

confidence: 99%

Mathematical modelling of impurity deposition during evaporation of dirty liquid in a porous material

Luckins,

Breward,

Griffiths

et al. 2024

J. Fluid Mech.

View full text Add to dashboard Cite

When a contaminated liquid evaporates from within a porous material, the impurities or dirt accumulate and deposit within the pore space. This occurs during the cleaning of filters and fouling of textiles, and is related to the ‘coffee-ring’ problem. To investigate how and where dirt is deposited in the pore space, we present a model for the motion of an evaporation front through a porous material, and the related accumulation, transport, and deposition of dirt, assuming that the liquid remains stationary. For physically relevant parameters, vapour transport out of the porous material is quasi-steady and we derive a single ordinary differential equation describing the motion of the evaporation front in time. Model solutions exhibit spatially non-uniform profiles of the deposited dirt-layer thickness through the porous material. The dirt accumulation and evaporation problems are coupled: deposited dirt hinders vapour transport through the porous material, slowing the evaporation. We identify two scenarios in which the porous material becomes clogged with dirt. Accumulation of suspended dirt at the evaporating interface along with slow dirt diffusion results in the deposited dirt layers clogging the pores at the evaporating interface, halting the drying and trapping liquid in the porous material. Alternatively, slow dirt deposition results in the suspended dirt being pushed far into the porous material by the evaporation, eventually leaving only dirt (with no liquid) in the pore space. We investigate the dynamics of both clogging scenarios, characterising the parameter regimes for which each occurs. Both clogging scenarios must be avoided in practice since they may be detrimental to future filter efficacy or textile breathability.

show abstract

Fluid-flow effects in the reactive decontamination of porous materials driven by chemical swelling or contraction

Cited by 2 publications

References 29 publications

The effect of pore-scale contaminant distribution on the reactive decontamination of porous media

The effect of pore-scale contaminant distribution on the reactive decontamination of porous media

Mathematical modelling of impurity deposition during evaporation of dirty liquid in a porous material

Contact Info

Product

Resources

About