Integrated design of surfactant enhanced DNAPL remediation: efficient supersolubilization and gradient systems

Sabatini, David A.; Knox, Robert C.; Harwell, Jeffrey H.; Wu, Bin

doi:10.1016/s0169-7722(00)00121-2

Cited by 80 publications

(70 citation statements)

References 20 publications

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“…4,42 Due to the consumer lifestyle of health and sustainability (LOHAS) requiring bio-based concepts it is a must to formulate and characterize microemulsions based on biological amphiphiles 43 and different kinds of renewable feedstock oils (RFOs). 5,37,44,45 Nowadays green microemulsions are already on the market. 32,42,43,46 Especially mono-alkyl esters made from renewable biological sources such as vegetable oils or animal fats have been investigated, and the physical properties of microemulsions with these compounds as the oil phase are of growing interest.…”

Section: Introductionmentioning

confidence: 99%

Microemulsions with renewable feedstock oils

2012

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In this paper we discuss the influence of chemical structures of renewable feedstock oils (RFOs) on the domains of existence and the nano-structures of microemulsions. We compare the results to those of classical microemulsions containing classical n-alkanes. First, the domains of microemulsions obtained from the melt of water, sodium dodecyl sulfate (SDS) as surfactant, 1-pentanol as co-surfactant and different RFOs (or RFO melts) in pseudo-ternary phase diagrams are presented. A surfactantco-surfactant mass ratio of 1 : 2 is kept constant and the RFO (or RFO melt) is considered as a pseudo-constituent. Two different fatty methyl ester (FAME) biodiesels from rapeseed and cuphea oils, rapeseed oil, "TBK" biodiesel from rapeseed oil, limonene, and different mixtures of limonene to FAME-rapeseed biodiesel and FAME-rapeseed biodiesel to FAME-cuphea biodiesel are used as RFOs or RFO melts. Second, conductivity data are shown along an experimental path having a constant RFO or RFO melt : (surfactant-co-surfactant) mass ratio, whereas the water content is varied. All obtained data are then compared to data from previous studies with a series of n-alkanes (from n-hexane to n-hexadecane). As the main conclusion it is found that RFOs or RFO melts can easily substitute n-alkanes. From the chemical structure of the oils, it appears that not only the polarity of the oil plays an important role but also does the absolute size of the oil molecules. In all cases microemulsion systems exhibit percolative behavior.

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Section: Introductionmentioning

confidence: 99%

Microemulsions with renewable feedstock oils

2012

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“…Interfacial tension between the hydrocarbon and aqueous phases is largely responsible for trapping the hydrocarbon in the porous matrix, and a reduction of several orders of magnitude in interfacial tension is needed for hydrocarbon mobilization (1,15,47). To achieve large reductions in interfacial tension, surfactant concentrations significantly above that needed to form micelles (i.e., the critical micelle concentration) are required (7,41,42). The high chemical costs have prevented the widespread use of surfactants for enhanced oil recovery.…”

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confidence: 99%

In Situ Biosurfactant Production by Bacillus Strains Injected into a Limestone Petroleum Reservoir

Youssef

Simpson

Duncan

et al. 2007

Appl Environ Microbiol

229

140

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Biosurfactant-mediated oil recovery may be an economic approach for recovery of significant amounts of oil entrapped in reservoirs, but evidence that biosurfactants can be produced in situ at concentrations needed to mobilize oil is lacking. We tested whether two Bacillus strains that produce lipopeptide biosurfactants can metabolize and produce their biosurfactants in an oil reservoir. Five wells that produce from the same Viola limestone formation were used. Two wells received an inoculum (a mixture of Bacillus strain RS-1 and Bacillus subtilis subsp. spizizenii NRRL B-23049) and nutrients (glucose, sodium nitrate, and trace metals), two wells received just nutrients, and one well received only formation water. Results showed in situ metabolism and biosurfactant production. The average concentration of lipopeptide biosurfactant in the produced fluids of the inoculated wells was about 90 mg/liter. This concentration is approximately nine times the minimum concentration required to mobilize entrapped oil from sandstone cores. Carbon dioxide, acetate, lactate, ethanol, and 2,3-butanediol were detected in the produced fluids of the inoculated wells. Only CO 2 and ethanol were detected in the produced fluids of the nutrient-only-treated wells. Microbiological and molecular data showed that the microorganisms injected into the formation were retrieved in the produced fluids of the inoculated wells. We provide essential data for modeling microbial oil recovery processes in situ, including growth rates (0.06 ؎ 0.01 h ؊1 ), carbon balances (107% ؎ 34%), biosurfactant production rates (0.02 ؎ 0.001 h ؊1 ), and biosurfactant yields (0.015 ؎ 0.001 mol biosurfactant/mol glucose). The data demonstrate the technical feasibility of microbial processes for oil recovery.

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“…Large changes in the capillary number (about a factor of 1000) are needed for substantial oil recovery [46]. The Chun-Huh relationship demonstrates that as the IFT decreases, the mass of oil solubilized per mass of surfactant increases [47]. Capillary (trapping) number curves illustrate that there is a threshold IFT below which significant mobilization occurs.…”

Section: Factors Affecting Oil Recoverymentioning

confidence: 99%

“…How these variations in structure affect the interfacial activity of the compounds is not well understood, but slight variations in structure do affect activity [73]. Since mixtures of synthetic surfactants are known to be more effective than pure surfactants in mobilizing complex hydrocarbons such as crude oil [47], biosurfactants have a natural advantage. The use of biosurfactants to mobilize residual hydrocarbon has met with mixed results.…”

Section: Biosurfactantsmentioning

confidence: 99%