Effects of colloidal humic acid on the transport of sulfa antibiotics through a saturated porous medium under different hydrochemical conditions

2018 ◽  
Vol 18 (6) ◽  
pp. 2199-2207 ◽  
Author(s):  
Xiujuan Liang ◽  
Dan Liu ◽  
Jingjing Zhou ◽  
Yuling Zhang ◽  
Wenjing Zhang
Keyword(s):  
Particle Size ◽  
Porous Medium ◽  
Porous Media ◽  
Humic Acid ◽  
Ionic Strength ◽  
Divalent Cation ◽  
Saturated Porous Medium ◽  
Column Experiments ◽  
Breakthrough Concentration ◽  
Hydrochemical Conditions

Abstract Colloidal humic acid (HA) acts as a vector that can facilitate the transport of contaminants in groundwater. However, investigations of factors that enhance the transport of sulfa antibiotics when there are colloids present remain incomplete to date. In this study, column experiments were performed under different conditions (particle size, pH, ionic strength, cation valence, colloidal concentration) using 0.25 mg/L sulfamerazine (SM) with or without colloids. The results showed that antibiotics were more easily deposited on the surface of porous media with a diameter of 0.22 mm than 0.45 mm. As the pH increased from 6 to 8, adding colloidal HA increased the maximum breakthrough concentration from 0.94 to 1 for SM. Adding colloidal HA at different NaCl concentrations decreased the maximum C/C0 ratio from 0.97 to 0.92. However, adding colloidal HA changed the C/C0 ratio more when the divalent cation (Ca2+) was present. Overall, increasing the colloidal HA concentration clearly caused the effluent sulfamerazine concentration to increase.

scholarly journals Colloid clogging of saturated porous media under varying ionic strength and roughness during managed aquifer recharge

2019 ◽  
Vol 9 (3) ◽  
pp. 225-231 ◽  
Author(s):  
Du Xinqiang ◽  
Song Yalin ◽  
Ye Xueyan ◽  
Luo Ran
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Ionic Strength ◽  
Smooth Surface ◽  
Saturated Porous Medium ◽  
Managed Aquifer Recharge ◽  
Permeability Reduction ◽  
Saturated Porous Media ◽  
Aquifer Recharge ◽  
Pore Throat

Abstract Column experiments were conducted to examine the clogging effects of colloids under controlled conditions of solution ionic strength (IS) and porous media roughness. The results showed that colloids in recharge water play an important role in the clogging process of saturated porous media, such that even a small amount of colloid may cause a large reduction in the permeability of the porous medium. Clogging at the pore throat was inferred to be the main reason for the severe permeability reduction of porous media. The characteristics of colloid clogging were clearly influenced by both IS and medium roughness. Recharge water with a higher IS facilitated greater attachment of colloids to the surface of the saturated porous medium, which lead to superficial clogging, while collectors with a rough surface resulted in greater clogging than collectors with a smooth surface.

Column experiments to investigate transport of colloidal humic acid through porous media during managed aquifer recharge

2016 ◽  
Vol 25 (1) ◽  
pp. 79-89 ◽  
Author(s):  
Dan Liu ◽  
Jingjing Zhou ◽  
Wenjing Zhang ◽  
Ying Huan ◽  
Xipeng Yu ◽  
...  
Keyword(s):  
Porous Media ◽  
Humic Acid ◽  
Managed Aquifer Recharge ◽  
Column Experiments ◽  
Aquifer Recharge

Stability of Bioconvection in Suspensions of Gyrotactic Microorganisms in Porous Media

2002 ◽  
Author(s):  
A. V. Kuznetsov ◽  
A. A. Avramenko
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Saturated Porous Medium ◽  
Critical Value ◽  
Numerical Results ◽  
Velocity Fluctuations ◽  
Gyrotactic Microorganisms ◽  
Upward Direction ◽  
Upward Velocity ◽  
Fluid Saturated Porous Medium

In this paper, a model of bioconvection in a suspension of gyrotactic motile microorganisms in a fluid saturated porous medium is suggested. The microorganisms considered in this paper are heavier than water and gyrotactic behavior results in their swimming towards the regions of most rapid downflow. Because of that, the regions of downflow become denser than the regions of upflow. Buoyancy increases the upward velocity in the regions of upflow and downward velocity in the regions of downflow, thus enhancing the velocity fluctuations. The experiments performed by Kessler (1986) and the numerical results of Kuznetsov and Jiang (2001) indicate that if the permeability of porous medium is sufficiently small it will prevent the development of convection instability. However, for practical purposes, in order to maximize the flux of the cells in the upward direction it is desirable to have the permeability of the porous medium as high as possible. The aim of this paper is to investigate the value of critical permeability. If permeability is smaller than this critical value bioconvection does not occur and microorganisms simply swim in the upward direction.

scholarly journals Transient Fluid Motions in Saturated Porous Media

1957 ◽  
Vol 10 (1) ◽  
pp. 43 ◽  
Author(s):  
JR Philip
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Heat Conduction ◽  
Exact Solutions ◽  
Kinematic Viscosity ◽  
Saturated Porous Medium ◽  
Steady Motion ◽  
Potential Gradient ◽  
Saturated Porous Media ◽  
Approximate Analysis

The transition from rest to steady motion on the sudden application of a potential gradient to the fluid contained in a saturated porous medium is investigated. An approximate analysis gives the result that the time of the effective establishment of the steady motion is proportional to the permeability and inversely proportional to the kinematic viscosity. Two exact solutions (one of them new) for simple cases suggest that the approximate analysis is remarkably accurate. An analogy between this problem and one in heat conduction makes the relevant results in that field immediately applicable here.

Non-Darcy Mixed Convection With Thermal Dispersion in a Saturated Porous Medium

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
V. V. Sobha ◽  
R. Y. Vasudeva ◽  
K. Ramakrishna ◽  
K. Hema Latha
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Porous Media ◽  
Nusselt Number ◽  
Mixed Convection ◽  
Vertical Plate ◽  
Saturated Porous Medium ◽  
Thermal Dispersion ◽  
Convection In Porous Media ◽  
Infinite Vertical Plate

Thermal dispersion due to local flows is significant in heat transfer with forced convection in porous media. The effects of parametrized melting (M), thermal dispersion (D), inertia (F), and mixed convection (Ra/Pe) on the velocity distribution, temperature, and Nusselt number on non-Darcy, mixed convective heat transfer from an infinite vertical plate embedded in a saturated porous medium are examined. It is observed that the Nusselt number decreases with increase in melting parameter and increases with increase in thermal dispersion.

Modeling of magmatic channel formation in thin lithosphere areas

2020 ◽  
Author(s):  
Yuri Perepechko ◽  
Konstantin Sorokin ◽  
Georgiy Vasilyev
Keyword(s):  
Mathematical Model ◽  
Porous Medium ◽  
Porous Media ◽  
Saturated Porous Medium ◽  
High Stress ◽  
Marked Change ◽  
Porous Matrix ◽  
Small Scale ◽  
Magma Intrusion ◽  
Magma Flow

<p>The aim of the research is to construct a mathematical model of the formation of a fracture system in magma intrusion in the permeable zones of the lithosphere and on this basis to study the formation of magmatic channels in the lithosphere and crust. The lithosphere substrate is modeled by a saturated porous medium in which the processes of small-scale destruction in the mantle magma intrusion lead to the formation of faults and, consequently, to a magmatic channel. Destruction and occurrence of micro-fracture fields can be associated with both magma flow and external seismic effect leading to the rock breaking. The process of small-scale destruction is described within the framework of the dynamics of the elastoplastic fracture-porous medium and causes variations in the rheological properties of the lithosphere substrate. A feature of this process is the destruction substrate in the compression zone represented by a narrow area with a sharply changing concentration of micro-fractures. The micro-fracture accumulation provides the conversion of the broken area into a macro-fissure. The elastoplastic porous matrix in the destruction zone contains both broken and intact substrate, the relative content of which is determined by relaxation of deformations, the speed of which depends on stress and yield stress point according to the power law. The obtained mathematical model provides investigation of currents in fractured-porous media and their effect on the small-scale destruction. Based on the TVD-Runge Kutta method numerical simulation of the compressible fluid infiltration into the fracture-porous permeable channel has shown that stresses in the compression domain can reach stress limits of breaking and result in fracture formation. Change in relaxation time does not result in a marked change in stress fields. The concentration of maximum stresses is observed in the channel center leading to an increase in its fracture porosity. The computational results show the appearance of high stress values in the compression domain in the process of a liquid phase injection, for instance, magma, into a low-permeable fracture-porous layer. The introduction of the destruction criterion will help to associate the occurrence of such regions to the local breaking of the porous matrix. Thus, the proposed micro-fracture generation mechanism can be used to describe the formation of fracture or channels in micro-fracture porous media. Work is done on state assignment of IGM SB RAS with partial support from the Russian Foundation for Basic Research, grants No. 16-29-15131, 19-05-00788.</p>

Natural Convection Experiments in a Stratified Liquid-Saturated Porous Medium

1986 ◽  
Vol 108 (3) ◽  
pp. 660-666 ◽  
Author(s):  
D. C. Reda
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Porous Media ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Saturated Porous Medium ◽  
High Permeability ◽  
Transfer Rates ◽  
Variable Porosity ◽  
Radial Extent

Natural convection heat transfer from a constant-flux cylinder, immersed vertically through a stratified (two-layer) liquid-saturated porous medium, was investigated experimentally. Measured radial temperature profiles and heat transfer rates agreed well with numerical predictions based on the work of Hickox and Gartling. The 1:6 permeability-ratio interface existing between the two layers was found to effectively trap buoyancy-driven fluid motion within the high-permeability region, beneath the interface. Within this high-permeability region, Nusselt number versus Rayleigh number data were found to correlate with previously measured results, obtained for the same basic geometry, but with a fully permeable upper-surface hydrodynamic boundary condition. In both cases, the vertical and radial extent of the region under study were large compared to the radius of the heat source. Combined results indicate that, for a given Rayleigh number in the Darcy-flow regime, heat transfer rates from cylinders immersed vertically in uniform liquid-saturated porous media of large vertical and radial extent potentially approach limiting values. Variable-porosity effects which occur in unconsolidated porous media adjacent to solid boundaries were investigated numerically for cases where the particle-to-heater diameter ratio was small (≈ 10−2). Results showed variable-porosity effects to have a negligible influence on the thermal field adjacent to such boundaries under conditions of Darcy flow.

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