Humic Acid Transport in Water-Saturated Porous Media

Wei, Xiaorong; Shao, Mingan; Horton, Robert; Han, Xinning

doi:10.1007/s10666-008-9186-y

Cited by 13 publications

(9 citation statements)

References 34 publications

(43 reference statements)

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“…Similar observations have been stated in earlier works [25]. The attachment of humic compounds onto the porous media is primarily governed by the pH of the humic acid solution [25]. And furthermore, with a decrease in pH, the reduced sorption of bacteria in the presence of humic acid was found to be more significant and have been mentioned in earlier works [26].…”

Section: Effect Of Humic Acid On the Transport Of Bacteriasupporting

confidence: 89%

“…It was observed that with the increase in pH, the attachment/sorption of humic acid to the collector media reduced. Similar observations have been described in earlier studies [25]. The transport of humic acid was found to be affected by a change in pH, ionic strength, and grain size of the matrix.…”

Section: Effect Of Humic Acid On the Transport Of Bacteriasupporting

confidence: 89%

“…It was observed that the bacterial sorption reduced in the presence of humic acid. Similar observations have been stated in earlier works [25]. The attachment of humic compounds onto the porous media is primarily governed by the pH of the humic acid solution [25].…”

Section: Effect Of Humic Acid On the Transport Of Bacteriasupporting

confidence: 88%

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Transport of E. coli in Presence of Naturally Occuring Colloids in Saturated Porous Media

Madumathi

2017

Water Conserv Sci Eng

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This study focuses on the effects of organic (humic acid substances) and inorganic (bentonite clay, silicate, and kaolinite clay) colloids on the transport of bacteria under saturated flow conditions. The transport experiments of Escherichia coli were performed in 40-cm long column filled with river sand of diameter 400 μm. Batch sorption experiments were conducted to understand the attachment kinetics of bacteria in the presence of humic acid and clay colloids. Humic acid was found to enhance the transport of bacteria by 17.3% in the presence of NaCl and by 10.3% in the presence of CaCl 2 while clay colloids were found to reduce the transport. The transport of bacteria decreased by 11.8, 33.8, and 67% (in the presence of NaCl) and by 58.8, 41.18, and 76.5% (in the presence of CaCl 2 ) with bentonite clay, silicate, and kaolinite clay colloids, respectively. The addition of divalent ion enhanced the complexity leading to the formation of complexes thereby reducing the transport. The combined existence of these colloids, the water chemistry, and the chemical composition of the colloids could govern the interaction processes in the subsurface matrix and can hence influence the transport of biocolloids in the environment significantly.

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Section: Effect Of Humic Acid On the Transport Of Bacteriasupporting

confidence: 89%

Section: Effect Of Humic Acid On the Transport Of Bacteriasupporting

confidence: 89%

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Transport of E. coli in Presence of Naturally Occuring Colloids in Saturated Porous Media

Madumathi

2017

Water Conserv Sci Eng

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“…The pH of the bulk solution affects the transport behaviour of the HA in the sand columns because all charged surfaces in the system are pH dependent. An acidic pH enhances the retention of HA through decreases in the electrostatic repulsion by protonation of the carboxyl and hydroxyl groups (Kinniburgh et al , 1999; Wei et al , 2010). Hydrogen and Cu 2+ behave as potential‐determining ions on mineral surfaces and soil organic matter and can determine the electrochemical interactions between surfaces and colloids as well as the colloid mobility in porous media (Grolimund et al , 1998; Zhou et al , 2011).…”

Section: Discussionmentioning

confidence: 99%

“…However, all these studies do not consider the mechanics of colloid retention in the pore matrix. Recently, Wei et al (2010) have provided evidence of the importance of hydrodynamics in pore water and the role of sorption on transport of HA in sand columns under different electrokinetic conditions, pH and hydrodynamics.…”

Section: Introductionmentioning

confidence: 99%

Coupled transport of humic acids and copper through saturated porous media

Paradelo

Pérez‐Rodríguez

Fernández‐Calviño

et al. 2012

European J Soil Science

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The mechanism of mediated transport of copper (Cu) by humic acids (HA) in pore water was studied taking account of colloid filtration theory and by means of breakthrough experiments of HA in water‐saturated columns filled with quartz sand. The influence of pH and Cu2+ concentration on Cu–HA binding and retention of Cu–HA complexes in the matrix were analysed with colloid‐surface attachment models. Experiments were performed for differing Cu concentrations (0–20 mg l−1) and pH (5–7). Copper binding to HA increased with pH and Cu2+ addition, according to ion–humic complexation theory. The zeta potential of the HA became less negative with increasing amounts of Cu, which led to less electrostatic repulsion and an increase in the retention of the HA in the column. A kinetic colloid transport model with a random sequential adsorption (RSA) blocking function was well fitted to the experimental breakthrough curves (BTCs). The model accounted for heterogeneity in the adsorption sites in the quartz sand for all of the electrochemical conditions. For pH = 7, the transport of Cu was coupled with the HA, while at pH = 5, the transport occurred mostly as free Cu2+. Models of the influence of dissolved soil organic matter and electrochemical conditions on the fate of trace elements in the soil may contribute to a quantitative exploration of strategies for soil remediation and disposal of contaminated soil containing excessive amounts of trace elements.

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