Increase in volatilization of organic compounds using air sparging through addition in alcohol in a soil-water system

Chao, Huan‐Ping; Hsieh, Lin-Han Chiang; Tran, Hai Nguyen

doi:10.1016/j.jhazmat.2017.11.053

Cited by 22 publications

(7 citation statements)

References 34 publications

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“…The efficiency of ex-situ soil washing is affected by factors including washing time, soil-washing solution pH, surfactant concentration, agitation speed, soil to liquid ratio, washing temperature, on and off mode and number of extractions (Peng, Wu & Chen, 2011;Zou et al, 2009). Of these factors temperature and on and off mode are reported to be uneconomical and to have less impact, and we have conducted the experiments under room temperature, with one-time extraction, and with constant washing mode (Chao, Hsieh & Tran, 2018). For this research, we have included an airflow rate as an additional factor affecting washing efficiency and kept soil to liquid ratio constant at 1:20 from pre-experiment and reported ratios (Peng, Wu & Chen, 2011).…”

Section: Prescreening Of Washing Parameters and Surfactantsmentioning

confidence: 99%

“…The detachment of contaminants is due to reduced interfacial tension and bubble collapse forces created due to collusion with soil particles and the shear stress attributed to fluid velocity and subsequent lifting of contaminants to the surface of the washing container (Kim, Kim & Han, 2012). Incorporation of aeration to the soil washing system will also help in exposing the volatile and semi-volatile organic compounds for volatilization (Chao, Hsieh & Tran, 2018;Chao, Ong & Huang, 2008).…”

Section: Removal Efficiencymentioning

confidence: 99%

“…As the micro and mesopores of fine soil particles are smaller, they will have closer contact with the contaminant and will be held firmly by hydrophobic attraction. Whereas, coarser particles have smaller surface area,lower organic matter content and cation exchange capacity than fine particles which will lightly held the contaminants than finer soil particles (Amirianshoja et al, 2013;Chao, Hsieh & Tran, 2018). The higher surface area of finer particles will also affect pollutant removal as the surfactant absorption capacity of the soils will increase which ultimately affecting the effectiveness of soil washing.…”

Section: Effect Of Aeration On Soil Textural Classesmentioning

confidence: 99%

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Optimization of aeration enhanced surfactant soil washing for remediation of diesel-contaminated soils using response surface methodology

Ayele

Lü

Chen

2020

PeerJ

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Surfactant-enhanced soil washing has been used for remediation of organic pollutants for an extended period, but its effectiveness and wide application was limited by the high concentration of surfactants utilized. In this work, the efficiency of conventional soil washing performance was enhanced by 12–25% through the incorporation of air bubbles into the low concentration surfactant soil washing system. Surfactant selection pre-experiment using aerated and conventional soil washing reveals Brij 35 > TX100 > Tween 80 > Saponin in diesel oil removal. Optimization of the effect of time, surfactant concentration, pH, agitation speed, and airflow rate in five levels were undertaken using Response Surface Methodology and Central composite design. The optimum degree of variables achieved was 90 min of washing time, 370 mg/l of concentration, washing pH of 10,535 rpm of agitation speed and 7.2 l/min of airflow rate with 79.5% diesel removal. The high predicted R2 value of 0.9517 showed that the model could efficiently be used to predict diesel removal efficiency. The variation in efficiency of aeration assisted and conventional soil washing was variable depending on the type of surfactant, organic matter content of the soil, particle size distribution and level of pollutant weathering. The difference in removal efficiency of the two methods increases when the level of organic matter increases and when the particle size and age of contamination decreases.

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Section: Prescreening Of Washing Parameters and Surfactantsmentioning

confidence: 99%

Section: Removal Efficiencymentioning

confidence: 99%

Section: Effect Of Aeration On Soil Textural Classesmentioning

confidence: 99%

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Optimization of aeration enhanced surfactant soil washing for remediation of diesel-contaminated soils using response surface methodology

Ayele

Lü

Chen

2020

PeerJ

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“…Chao et al proposed the addition of alcohol in the repair process of air sparging (AS) to enhance remediation efficiency [19]. N-pentanol and n-heptanol were selected as strengthening reagents as both could enhance the removal efficiency of organic compounds; however, the effect of n-heptanol was stronger than that of n-pentanol.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on the Effects of Ethanol-Enhanced Steam Injection Remediation in Nitrobenzene-Contaminated Heterogeneous Aquifers

et al. 2021

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Steam injection is an effective technique for the remediation of aquifers polluted with volatile organic compounds. However, the application of steam injection technology requires a judicious selection of stratum media because the remediation effect of hot steam in heterogeneous layers with low permeability is not suitable. In this study, the removal effect of nitrobenzene in an aquifer was investigated through a series of two-dimensional sandbox experiments with different stratigraphic structures. Four types of alcohols were used during steam injection remediation to enhance the removal effect of nitrobenzene (NB)-contaminated heterogeneous aquifers. The principle of the removal mechanism of alcohol-enhanced organic compounds is that alcohols can reduce the surface tension of the contaminated water, resulting in Marangoni convection, thereby enhancing mass and heat transfer. The addition of alcohol may also reduce the azeotropic temperature of the system and enhance the volatility of organic compounds. The study revealed that all four alcohol types could reduce the surface tension from 72 mN/m to <30 mN/m. However, among these, only ethanol reduced the azeotropic temperature of NB by 15 °C, thereby reducing energy consumption and remediation costs. Therefore, ethanol was selected as an enhancing agent to reduce both surface tension and azeotropic temperature during steam injection. In the 2-D simulation tank, the interface between the low-and high-permeability strata in the layered heterogeneous aquifer had a blocking effect on steam transportation, which in turn caused a poor remediation effect in the upper low-permeability stratum. In the lens heterogeneous aquifer, steam flows around the lens, thereby weakening the remediation effect. After adding ethanol to the low-permeability zone, Marangoni convection was enhanced, which further enhanced the mass and heat transfer. In the layered and lens heterogeneous aquifers, the area affected by steam increased by 13% and 14%, respectively. Moreover, the average concentration of NB was reduced by 51% in layered heterogeneous aquifers and by 58% in low-permeability lenses by ethanol addition. These findings enhance the remediation effect of steam injection in heterogeneous porous media and contribute to improve the remediation efficiency of heterogeneous aquifers by steam injection.

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“…It depends not only on the soil conditions (e.g., water content and characteristic of soil) but also on the environmental conditions (e.g., wind speed, air relative humidity and temperature) and VOCs properties (Li et al 2004, Okamoto et al 2009, Tao et al 2017). In recent years, Wei (Wei et al 2018) and Chao (Chao et al 2018) studied the importance of temperature and wind speed on volatilization process from soil. The higher the temperature and wind speed are, the greater the volatilization rate will be.…”

Section: Introductionmentioning

confidence: 99%

Volatilization process of toluene from contaminated soil under consideration of co-existence of pore water

Liu

et al. 2021

Environ Sci Pollut Res

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The volatilization process of contaminants has been shown to play an important role in remediation of VOCs-contaminated soils. The aim of this paper is to study the volatilization characteristics of both toluene and water from soil, and to evaluate their interaction mechanism under different conditions. A test system is developed to measure mass loss of contaminants and water from soil by volatilization. It was found that basically the volatilization process could be divided into two stages in clay and one stage in sand. Two main in uential mechanisms of water on the volatilization of toluene include molecules competitive adsorption and blocking of volatilization channels. In addition, the evaporation process of water was restricted by volatilization of toluene. Volatilization rate of toluene would increase with the increase of water content when the water content was low. But it would decrease with the increase of water content when the water content was higher than 15% in clay. In addition, there existed an optimal water content (15%) under which the maxium volatilization rate could be achieved.

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Increase in volatilization of organic compounds using air sparging through addition in alcohol in a soil-water system

Cited by 22 publications

References 34 publications

Optimization of aeration enhanced surfactant soil washing for remediation of diesel-contaminated soils using response surface methodology

Optimization of aeration enhanced surfactant soil washing for remediation of diesel-contaminated soils using response surface methodology

Experimental Investigation on the Effects of Ethanol-Enhanced Steam Injection Remediation in Nitrobenzene-Contaminated Heterogeneous Aquifers

Volatilization process of toluene from contaminated soil under consideration of co-existence of pore water

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