Review of the fundamental geochemical and physical behaviors of organoclays in barrier applications

Zhao, Qian; Choo, Hyunwook; Bhatt, Aditya; Burns, Susan E.; Bate, Bate

doi:10.1016/j.clay.2016.11.024

Cited by 74 publications

(47 citation statements)

References 135 publications

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“…The application of the organo-clay in the landfill liners has been also investigated in the recent researches. This Zhao et al [13] reviewed several properties of organoclays including the fundamental behavior of organoclays, focusing on geochemical properties such as electrokinetic potential, hydrophobicity, sorptivity, adsorption of nonpolar compounds and electrical conductivity, hydraulic conductivity, strength, thermal stability and thermal conductivity. Moreover, Javadi et al [14] carried out several laboratory tests to examine the swelling, permeability and contaminant retention of compacted silty clay amended with an organoclay (hexa decyl trimethyl ammonium (HDTMA) modified bentonite) against both gasoline and organic solution.…”

Section: Introductionmentioning

confidence: 99%

Improving the permeability and adsorption of phenol by organophilic clay in clay liners

Heidarzadeh

Parhizi

2019

Environmental Engineering Research

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The aim of this study is to investigate the effect of five different combinations including: sand 70%, bentonite 30% (S70B30)-sand 80%, bentonite 20% (S80B20)-sand 80%, organophilic 20% (S80M20)-sand 60%, bentonite 20%, organophilic 20% (S60B20M20) and sand 75% -bentonite 15% -organophilic 10% (S75B15M10) on landfill linear structure in order to decrease phenol leaching. Hydraulic conductivity and adsorption behavior of the samples were investigated. The results demonstrated that the lowest hydraulic conductivity coefficient (1.16 ×       ) was obtained for S70B30. Furthermore, adding more than 20% of bentonite had no significant effect on reducing permeability. Moreover, Freundlich isotherm was introduced as the best model explaining adsorption behaviour due to its highest determination coefficient (0.945). The best samples for adsorption capacity of phenol and for both permeability and adsorption are S80M20 and S60B20M20, respectively. Although the presence of bentonite was effective in reducing hydraulic conductivity, organic clay had no considerable impact on reducing permeability. Though, it's an exceptional role in adsorbing organic contaminants including phenol cannot be ignored. To meet all regulatory constraints, the optimal compound is made up of 10.2% of bentonite and 2.8% of organophilic clays with a minimized cost of 13.64 ($/ton).

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Section: Introductionmentioning

confidence: 99%

Improving the permeability and adsorption of phenol by organophilic clay in clay liners

Heidarzadeh

Parhizi

2019

Environmental Engineering Research

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“…To protect the environment surrounding waste landfill sites, especially nuclear waste landfill sites, the landfill site needs to be isolated from its surroundings by a barrier made of low-permeability materials [1]. Expansive clays such as montmorillonite and kaolinite are materials commonly used to make barriers because of their low permeability coefficient [2][3][4]. The permeability coefficients of montmorillonite and kaolinite are in the range of 10 −11 to 10 −12 m/s [5].…”

Section: Introductionmentioning

confidence: 99%

Permeability Evaluation of Clay-quartz Mixtures Based on Low-Field NMR and Fractal Analysis

Sha

Wang

2020

Applied Sciences

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Nuclear magnetic resonance (NMR) technology has been widely used for predicting permeability coefficients of porous medium, such as shales, sandstones, and coals. However, there have been limited studies on the prediction model of clay-quartz mixtures based on NMR technology. In this study, evaporation tests at 40 °C and NMR tests were simultaneously performed on eight clay-quartz mixtures with different mineral compositions. The results show that during the evaporation process, the decay rate of T2 total signal amplitudes was constant at first, and then decreased to 0 after a period of time. Based on the decay rate, the evaporation process was divided into two stages: the constant rate stage and the falling rate stage. Based on the two stages, the T2 cut-offs of eight mixtures were determined. The water in the mixture was divided into two parts by the T2 cut-off: the free water and the bound water. The prediction model of permeability coefficients of clay-quartz mixtures was established based on the Timur-Coates model. In order to simplify the process of predicting the permeability coefficient, fractal analysis was used to develop the relationship between the T2 cut-off and fractal dimension of the T2 spectrum of saturated mixture. A simplified method for predicting permeability coefficients of clay-quartz mixtures based on NMR technology without centrifugal and evaporation experiments was also proposed.

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“…Typically, organoclays are many times more effective than naturally occurring clays in the sorption of organic contaminants from water. The sorptivity of organoclays is influenced by several factors including nature of the sorbates, solvent, co-solvent and co-sorbates, distribution of sorbates in aqueous and in the gaseous phase and temperature, pH and ionic strength of the solution (Delle Site 2001; Zhao et al 2016).…”

Section: Sorptionmentioning

confidence: 99%

“…Organic cations bound to the clay surfaces can facilitate the binding of organic molecules to the clay mineral via adsorption and partitioning . Organoclays exhibit low conductivity, high swelling tendency, and high plasticity in organic liquids (Benson et al 2015;Zhao et al 2016). Therefore, organoclays can be used as an amendment in barrier systems such as CCLs and GCLs to improve their hydraulic performance when faced with non-polar organic liquids.…”

Section: Several Types Of Natural and Engineered Materials Have Been mentioning

confidence: 99%

Cationic surfactant modification and its impact on the engineering behaviors of montmorillonite.

Ghavami¹

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Review of the fundamental geochemical and physical behaviors of organoclays in barrier applications

Cited by 74 publications

References 135 publications

Improving the permeability and adsorption of phenol by organophilic clay in clay liners

Improving the permeability and adsorption of phenol by organophilic clay in clay liners

Permeability Evaluation of Clay-quartz Mixtures Based on Low-Field NMR and Fractal Analysis

Cationic surfactant modification and its impact on the engineering behaviors of montmorillonite.

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