Adhesion of Colloids and Bacteria to Porous Media: A Critical Review

Adhesion of colloids and bacteria to various surfaces is important for a variety of environmental phenomena including microbial biofouling and contamination prevention. Under saturated conditions, both colloids and bacteria have the opportunity to attach to porous medium surfaces. Under water unsaturated conditions or in the presence of the air-water interface, besides the porous medium surfaces, colloids and bacteria can also attach to the air-water interface, including the air-water-solid threephase interface. The magnitudes of adhesion of colloids and bacteria are correlated to the interactions of the colloids and bacteria with the surfaces, which are a function of their surface physicochemical properties. In this review, adhesion theories are revisited and adhesion of colloids and bacteria to porous media and the air-water interface is discussed. The interaction forces are quantified using various theoretical models including the DLVO models and used to interpret related adhesion. The impact of surfactants on colloid and bacterial adhesion is also discussed. The review also includes the implementation of the adhesion theory in interpreting colloid and bacterial fate and transport in the subsurface soil.

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Microplastic water repellency impacts water flow and microplastic transport in soils

10.5194/egusphere-egu21-964 ◽

2021 ◽

Author(s):

Andreas Cramer ◽

Pascal Benard ◽

Anders Kaestner ◽

Mohsen Zare ◽

Andrea Carminati

Keyword(s):

Porous Media ◽

Water Flow ◽

Capillary Rise ◽

Water Repellency ◽

Water Infiltration ◽

Water Interface ◽

Deuterated Water ◽

X Ray ◽

Air Water Interface ◽

The Impact

Soils are considered the largest sink of microplastic particles (MP) in terrestrial ecosystems. However, there is little knowledge on the implications of MP contaminating soils. In particular, we do not know the extent of and conditions under which MP are transported through porous media and, if they are deposited, how they affect soil hydraulic properties and soil moisture dynamics. We hypothesize that: 1) hydrophobic MP enhance soil water repellency; 2) isolated MP are displaced and transported by the air-water interface; 3) clusters of MP impede water flow and are retained in air-filled pores.We tested these hypotheses in mixtures of MP (&#181;m range) and sands (mm range) in a series of experiments. The Sessile Drop Method (SDM) was applied to measure the average contact angle (CA) of the mixtures for MP and model porous media in the same size range, ranging from 0 - 100 % MP content. Based on the specific surface and shape factor of MP and soil particles, the results are extrapolated to different MP and soil particle sizes. Capillary rise experiments were performed to measure the impact of MP on water infiltration. The applied MP contents of 0.35 % and 1.05 % reflect an average CA of 60&#176; and 90&#176; from the SDM extrapolation. Capillary rise of water and ethanol were carried out to estimate the apparent CA. Additionally and with the same MP content, we simultaneously imaged in three-dimensions the movement of deuterated water and MP during repeated drying / wetting cycles using X-Ray and Neutron tomography (at the beamline ICON, PSI). The different neutron attenuation coefficients of deuterated water and MP allows for estimating their distribution in the sand packing.Already at MP contents of 5 % the CA measured with the SDM exhibited a steep increase and reached 59&#176; to 81&#176;, depending on the grain size of MP. The capillary rise experiments showed that MP reduce capillary rise. The apparent CA (43&#176; and 53&#176;) were smaller compared to the average CA from the SDM (60&#176; and 90&#176;), but the added MP increased air entrapment during capillary rise leading to a reduced saturation of the pore space (18 % and 16.5 %). Accumulation of MP at the advancing air-water interface was visible. Neutron and X-ray imaging showed at high resolution that regions with major MP content are water repellent and, are bypassed by water flow, and remain in air-filled pores.Extrapolation of these results to soils suggests that in microregions with high MP contents, water infiltration is hindered. The low water content in these microregions might limit MP degradation due to reductions in: hydrolysis, coating of MP by e.g. dissolved organic substances, and colonization by microorganisms.

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Thermoresponsive microgels at the air–water interface: the impact of the swelling state on interfacial conformation

Soft Matter ◽

10.1039/c6sm01375a ◽

2017 ◽

Vol 13 (1) ◽

pp. 230-238 ◽

Cited By ~ 17

Author(s):

J. Maldonado-Valderrama ◽

T. del Castillo-Santaella ◽

I. Adroher-Benítez ◽

A. Moncho-Jordá ◽

A. Martín-Molina

Keyword(s):

Water Interface ◽

Temperature Responsive ◽

Air Water Interface ◽

The Impact

Poly(N-vinylcaprolactam) (PVCL) is a new temperature-responsive type of polymer microgel with improved biocompatibility as compared to more commonly used poly(N-isopropylacrylamide) (PNIPAM).

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Bacteria transport in an unsaturated porous media: incorporation of air–water interface area model into transport modelling

Hydrological Processes ◽

10.1002/hyp.6799 ◽

2008 ◽

Vol 22 (13) ◽

pp. 2370-2376 ◽

Cited By ~ 13

Author(s):

Min-Kyu Kim ◽

Song-Bae Kim ◽

Seong-Jik Park

Keyword(s):

Porous Media ◽

Water Interface ◽

Unsaturated Porous Media ◽

Interface Area ◽

Transport Modelling ◽

Bacteria Transport ◽

Area Model ◽

Air Water Interface

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A homogenised model for flow, transport and sorption in a heterogeneous porous medium

Journal of Fluid Mechanics ◽

10.1017/jfm.2021.938 ◽

2021 ◽

Vol 932 ◽

Author(s):

L.C. Auton ◽

S. Pramanik ◽

M.P. Dalwadi ◽

C.W. MacMinn ◽

I.M. Griffiths

Keyword(s):

Porous Medium ◽

Porous Media ◽

Multiple Scales ◽

Effective Diffusivity ◽

Rectangular Lattice ◽

Mathematical Framework ◽

Anisotropic Flow ◽

Flow And Transport ◽

Soft Porous Media ◽

The Impact

A major challenge in flow through porous media is to better understand the link between microstructure and macroscale flow and transport. For idealised microstructures, the mathematical framework of homogenisation theory can be used for this purpose. Here, we consider a two-dimensional microstructure comprising an array of obstacles of smooth but arbitrary shape, the size and spacing of which can vary along the length of the porous medium. We use homogenisation via the method of multiple scales to systematically upscale a novel problem involving cells of varying area to obtain effective continuum equations for macroscale flow and transport. The equations are characterised by the local porosity, a local anisotropic flow permeability, an effective local anisotropic solute diffusivity and an effective local adsorption rate. These macroscale properties depend non-trivially on the two degrees of microstructural geometric freedom in our problem: obstacle size and obstacle spacing. We exploit this dependence to construct and compare scenarios where the same porosity profile results from different combinations of obstacle size and spacing. We focus on a simple example geometry comprising circular obstacles on a rectangular lattice, for which we numerically determine the macroscale permeability and effective diffusivity. We investigate scenarios where the porosity is spatially uniform but the permeability and diffusivity are not. Our results may be useful in the design of filters or for studying the impact of deformation on transport in soft porous media.

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Effects of sedimentation, microgravity, hydrodynamic mixing and air–water interface on α-synuclein amyloid formation

Chemical Science ◽

10.1039/d0sc00281j ◽

2020 ◽

Vol 11 (14) ◽

pp. 3687-3693 ◽

Cited By ~ 2

Author(s):

Jiangtao Zhou ◽

Francesco S. Ruggeri ◽

Manuela R. Zimmermann ◽

Georg Meisl ◽

Giovanni Longo ◽

...

Keyword(s):

Comprehensive Analysis ◽

Aggregation Kinetics ◽

Amyloid Formation ◽

Water Interface ◽

Air Water Interface ◽

The Impact

A comprehensive analysis on the impact of sedimentation, microgravity hydrodynamic mixing and air–water interface on α-synuclein aggregation kinetics.

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Diffusion limited mixing in heterogeneous porous media

10.5194/egusphere-egu21-15721 ◽

2021 ◽

Author(s):

Mayumi Hamada ◽

Pietro de Anna

Keyword(s):

Porous Medium ◽

Porous Media ◽

Flow Field ◽

Fast Diffusion ◽

Pore Scale ◽

Mixing Processes ◽

Local Flow ◽

Gaussian Shape ◽

Diffusion Limited ◽

The Impact

A pore-scale description of the transport and mixing processes is particularly relevant when looking at biological and chemical reactions. For instance, a microbial population growth is controlled by local concentrations of nutrients and oxygen, and chemical reaction are driven by molecular-scale concentration gradients. The heterogeneous flow field typically found in porous media results from the contrast of velocities that deforms and elongates the mixing fronts between solutes that often evolves through a lamella-like topology. For continuous Darcy type flow field a novel framework that describes the statistical distribution of concentration being transported was recently developed (Le Borgne et al., JFM 2015). In this model, concentrations in each lamella are distributed as a Gaussian-like profile which experiences diffusion in the transverse direction while the lamella is elongated by advection along the local flow direction. The evolving concentration field is described as the superposition of each lamella. We hypothesize that this novel view, while perfectly predicting the distribution of concentration for Darcy scale mixing processes, will breakdown when the processes description is at the pore scale. Indeed the presence of solid and impermeable boundaries prevents lamella concentration to diffuse freely according to the a Gaussian shape, and therefore changes the mixing front profile, the lamella superposition and elongation rules. Previous work (Hamada et al, PRF, 2020) demonstrated that the presence of solid boundaries leads to an enhanced diffusion and thus fast homogenization of concentrations. In a purely diffusive process the local mixing time is reduced by a factor of ten with respect to the continuous case and concentration gradient are dissipated exponentially fast while a power law decrease is observed in continuous medium. To investigate the impact of these mechanisms on mixing we developed an experimental set-up to visualize and quantify the displacement of a conservative tracer in a synthetic porous medium. The designed apparatus allows to obtain high resolution concentration measurements at the pore scale. We show that the resulting mixing measures, computed in terms of concentration probability density function and dilution index values, diverge qualitatively and quantitatively from what happens in a continuous domain. These observations suggest that description of pore-scale diffusion-limited mixing requires model that takes into account the confined nature of porous medium, otherwise we will tend to overestimate concentration value and neglect the fast diffusion dynamic taking place at microscopic level.

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Modelling and simulation of waves in three-layer porous media

Nonlinear Processes in Geophysics ◽

10.5194/npg-20-1023-2013 ◽

2013 ◽

Vol 20 (6) ◽

pp. 1023-1030 ◽

Cited By ~ 3

Author(s):

S. R. Pudjaprasetya

Keyword(s):

Porous Medium ◽

Porous Media ◽

Gravity Waves ◽

Wave Reflection ◽

Single Layer ◽

Reflection And Transmission ◽

Weakly Nonlinear ◽

Model Equations ◽

The Impact ◽

Wave Transmission Coefficient

Abstract. The propagation of gravity waves in an emerged three-layer porous medium is considered in this paper. Based on the assumption that the flow can be described by Darcy's Law, an asymptotic theory is developed for small-amplitude long waves. This leads to a weakly nonlinear Boussinesq-type diffusion equation for the wave height, with coefficients dependent on the conductivities and depths of each layer. In the limit of equal conductivities of all layers, the equation reduces to the single-layer result recorded in the literature. The model equations are numerically integrated in the case of an incident monochromatic wave hitting the layers. The results exhibit dissipation and also a downstream net height rise at infinity. Wave transmission coefficient in three-layer porous media with conductivity of mangrove is discussed. Numerically, propagation of an initial solitary wave through a porous medium shows the emergence of wave reflection and transmission that both evolve as permanent waves. Additionally we examine the impact of a solitary gravity wave on a porous medium breakwater.

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Impact of artificial monolayer application on stored water quality at the air–water interface

Water Science & Technology ◽

10.2166/wst.2015.337 ◽

2015 ◽

Vol 72 (7) ◽

pp. 1250-1256 ◽

Cited By ~ 1

Author(s):

P. Pittaway ◽

V. Martínez-Alvarez ◽

N. Hancock ◽

B. Gallego-Elvira

Keyword(s):

Water Quality ◽

Oxygen Demand ◽

Cost Effective ◽

Subsurface Water ◽

Water Tank ◽

Water Interface ◽

Field Investigations ◽

Air Water Interface ◽

Large Water ◽

The Impact

Evaporation mitigation has the potential to significantly improve water use efficiency, with repeat applications of artificial monolayer formulations the most cost-effective strategy for large water storages. Field investigations of the impact of artificial monolayers on water quality have been limited by wind and wave turbulence, and beaching. Two suspended covers differing in permeability to wind and light were used to attenuate wind turbulence, to favour the maintenance of a condensed monolayer at the air/water interface of a 10 m diameter tank. An octadecanol formulation was applied twice-weekly to one of two covered tanks, while a third clean water tank remained uncovered for the 14-week duration of the trial. Microlayer and subsurface water samples were extracted once a week to distinguish impacts associated with the installation of covers, from the impact of prolonged monolayer application. The monolayer was selectively toxic to some phytoplankton, but the toxicity of hydrocarbons leaching from a replacement liner had a greater impact. Monolayer application did not increase water temperature, humified dissolved organic matter, or the biochemical oxygen demand, and did not reduce dissolved oxygen. The impact of an octadecanol monolayer on water quality and the microlayer may not be as detrimental as previously considered.

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