Surface Chemical Studies on Sphalerite and Galena Using Bacillus polymyxa

Santhiya, Deenan; Subramanian, S.; Natarajan, K.A.

doi:10.1006/jcis.2000.7374

Cited by 34 publications

(8 citation statements)

References 9 publications

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“…Neglecting the initial ballistic imbibition regime [74], which can be estimated to last just a few ps, we focus on the regime of viscous flow, where viscous dissipation prevails and acts against the capillarity-driven liquid uptake by the porous medium [75] [76][77] [78]. The competition of the constant Young-Laplace driving pressure and the increasing viscous drag in the liquid column behind the advancing imbibition front results in the Lucas-Washburn-…”

Section: (A)mentioning

confidence: 99%

Capillarity-Driven Oil Flow in Nanopores: Darcy Scale Analysis of Lucas–Washburn Imbibition Dynamics

Gruener

Huber

2018

Transp Porous Med

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We present gravimetrical and optical imaging experiments on the capillarity-driven imbibition of silicone oils in monolithic silica glasses traversed by 3D networks of pores (mesoporous Vycor glass with 6.5 nm or 10 nm pore diameters). As evidenced by a robust square-root-of-time Lucas-Washburn (L-W) filling kinetics, the capillary rise is governed by a balance of capillarity and viscous drag forces in the absence of inertia and gravitational effects over the entire experimental times studied, ranging from a few seconds up to 10 days. A video on the infiltration process corroborates a collective pore filling as well as pronounced imbibition front broadening resulting from the capillarity and permeability disorder, typical of Vycor glasses. The transport process is analyzed within a Darcy scale description, considering a generalized pre-factor of the L-W law, termed Lucas-Washburn-Darcy imbibition ability. It assumes a Hagen-Poiseuille velocity profile in the pores and depends on the porosity, the mean pore diameter, the tortuosity and the velocity slip length and thus on the effective hydraulic pore diameter. For both matrices a reduced imbibition speed and thus reduced imbibition ability, compared to the one assuming the nominal pore diameter, bulk fluidity and bulk capillarity, can be quantitatively traced to an immobile, pore-wall adsorbed boundary layer of 1.4 nm thickness. Presumably, it consists of a monolayer of water molecules adsorbed on the hydrophilic pore walls covered by a monolayer of flat-laying silicone oil molecules. Our study highlights the importance of immobile nanoscopic boundary layers on the flow in tight oil reservoirs as well as the validity of the Darcy scale description for transport in mesoporous media.

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Section: (A)mentioning

confidence: 99%

Capillarity-Driven Oil Flow in Nanopores: Darcy Scale Analysis of Lucas–Washburn Imbibition Dynamics

Gruener

Huber

2018

Transp Porous Med

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“…In general, there are three characteristic regimes during a capillary rise process [84,85,86]: (i) The initial, ballistic regime when the fluid particles enter the pore. In this region, the transport is governed by competition between inertia and molecule/surface interactions resulting in a linearly increasing capillary rise height [87,88,89]. (ii) The regime where inertia and viscous forces compete with capillarity [87,89].…”

Section: Theory Of Capillary Rise Dynamicsmentioning

confidence: 99%

“…In this region, the transport is governed by competition between inertia and molecule/surface interactions resulting in a linearly increasing capillary rise height [87,88,89]. (ii) The regime where inertia and viscous forces compete with capillarity [87,89]. (iii) The regime of viscous flow, where viscous forces prevail and act against the capillarity-driven liquid uptake by the porous medium [90,91,92].…”

Section: Theory Of Capillary Rise Dynamicsmentioning

confidence: 99%

Capillary rise dynamics of liquid hydrocarbons in mesoporous silica as explored by gravimetry, optical and neutron imaging: Nano-rheology and determination of pore size distributions from the shape of imbibition fronts

Gruener

Hermes

Schillinger

et al. 2016

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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We present combined gravimetrical, optical, and neutron imaging measurements of the capillarity-driven infiltration of mesoporous silica glass (Vycor) by hydrocarbons. Square-root-of-time Lucas-Washburn invasion kinetics are found for linear alkanes from n-decane (C10) to n-hexacontane (C60) and for squalane, a branched alkane, in porous monoliths with 6.5 nm or 10 nm mean pore diameter, respectively. Humiditydependent experiments allow us to study the influence on the imbibition kinetics of water layers adsorbed on the pore walls. Except for the longest molecule studied, C60, the invasion kinetics can be described by bulk fluidity and bulk capillarity, provided we assume a sticking, pore-wall adsorbed boundary layer, i.e. a monolayer of water covered by a monolayer of flat-laying hydrocarbons. For C60, however, an enhanced imbibition speed compared to the value expected in the bulk is found. This suggests the onset of velocity slippage at the silica walls or a reduced shear viscosity due to the transition towards a behaviour typical of polymer-like flow in confined geometries. Both, light scattering and neutron imaging, indicate a pronounced roughening of the imbibition fronts. Their overall shape and increase in width can be resolved by neutron imaging. The fronts can be described by a superposition of independent wetting fronts moving with pore size-dependent square-root-of-time laws and weighted according to the pore size distributions obtained from nitrogen gas sorption isotherms. This finding indicates that the shape of the imbibition front in a porous medium, such as Vycor glass, with interconnected, elongated pores, is solely determined by independent movements of liquid menisci. These are dictated by the Young-Laplace pressure and hydraulic permeability variations and thus the pore size variation at the invasion front. Our results suggest that pore size distributions can be derived from the broadening characteristics of imbibition fronts.

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“…The isolation and characterization of a novel polysaccharide-producing Bacillus polymyxa has been studied (15,16). The utility of Thiobacillus thiooxidans and Bacillus polymyxa in achieving the selective separation of galena from sphalerite has been recently reported by us in a series of papers (17)(18)(19).…”

Section: Introductionmentioning

confidence: 93%

Surface Chemical Studies on Sphalerite and Galena Using Extracellular Polysaccharides Isolated from Bacillus polymyxa

Santhiya

Subramanian

Natarajan

2002

Journal of Colloid and Interface Science

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119

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Surface Chemical Studies on Sphalerite and Galena Using Bacillus polymyxa

Cited by 34 publications

References 9 publications

Capillarity-Driven Oil Flow in Nanopores: Darcy Scale Analysis of Lucas–Washburn Imbibition Dynamics

Capillarity-Driven Oil Flow in Nanopores: Darcy Scale Analysis of Lucas–Washburn Imbibition Dynamics

Capillary rise dynamics of liquid hydrocarbons in mesoporous silica as explored by gravimetry, optical and neutron imaging: Nano-rheology and determination of pore size distributions from the shape of imbibition fronts

Surface Chemical Studies on Sphalerite and Galena Using Extracellular Polysaccharides Isolated from Bacillus polymyxa

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