Removal of hazardous oily waste from a soil matrix using surfactants and colloidal gas aphron suspensions under different flow conditions

Roy, Dipak; Valsaraj, K. T.; Constant, W. David; Darji, Mubeen

doi:10.1016/0304-3894(94)00028-x

Cited by 53 publications

(17 citation statements)

References 16 publications

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“…Colloidal gas aphrons have found numerous applications including (1) protein or bacteria separation [2,3], (2) soil remediation [4,5], (3) remediation of contaminated water [6,7], (4) fermentation and bioreactors [8], and (5) material synthesis [9][10][11]. They could also be used for oil recovery and fire fighting.…”

Section: Introductionmentioning

confidence: 99%

Rheology of colloidal gas aphrons (microfoams)

Larmignat

Vanderpool

Lai

et al. 2008

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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This paper reports on the effect of surfactant concentration and pipe shape and size on the rheological properties of colloidal gas aphrons (CGA) or microfoams. CGA consists of closely packed spherical gas bubbles with diameter ranging from 10 to 100 microns surrounded by a surfactant shell. It is produced by stirring an aqueous surfactant solution at high speed in a baffled beaker. Pipe flow experiments were performed in cylindrical pipes with diameter ranging from 1.0 to 3.0 mm under adiabatic laminar flow conditions. The porosity, bubble size distribution, surface tension, and pH were systematically measured. First, it is established that there was no slip velocity at the wall and CGA did not change morphology and porosity between the inlet and outlet of the pipes less than 2 mm in diameter. Compressibility effects were accounted for through the volume equalization approach. Then, pipe shape and diameter have no

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Section: Introductionmentioning

confidence: 99%

Rheology of colloidal gas aphrons (microfoams)

Larmignat

Vanderpool

Lai

et al. 2008

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…Micro-foam, or colloidal gas aphrons (CGAs), reportedly have been used for soil flushing in contaminated site remediation (Longe 1989;Roy et al 1994Roy et al , 1995a. CGAs consist of approximately 65% by volume gas and hence form a low-density liquid.…”

Section: Remediation With Micro-foammentioning

confidence: 99%

“…In a similar experiment to settings in Roy et al (1994), Roy et al (1995a) applied CGAs to flush residual levels of a light NAPL such as automatic transmission fluid (ATF) from a Superfund site soil. CGA suspensions were found to be more effective in washing ATF under both downflow and upflow modes.…”

Section: Remediation With Micro-foammentioning

confidence: 99%

Foam Transport in Porous Media - A Review

Zhang¹,

Freedman²,

Zhong³

2009

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Executive SummaryAmendment solutions with or without surfactants have been used to remove contaminants from soil. However, they have drawbacks in that amendment solutions often mobilize the plume, and its movement is controlled by gravity and preferential flow paths. Foam is an emulsion-like, two-phase system in which gas cells are dispersed in a liquid and separated by thin liquid films called lamellae. The potential advantages of using foams in sub-surface remediation include providing better control on the volume of fluids injected, uniformity of contact, and the ability to contain the migration of contaminant-laden liquids. It is expected that foam can serve as a carrier of amendments for vadose zone remediation, e.g., at the Hanford Site. As part of the U.S. Department of Energy's EM-20 program, a numerical simulation capability will be added to the Subsurface Transport Over Multiple Phases (STOMP) flow simulator. The primary purpose of this document is to review the modeling approaches of foam transport in porous media. However, as an aid to understanding the simulation approaches, some experiments under unsaturated conditions and the processes of foam transport are also reviewed.Foam may be formed when the surfactant concentration is above the critical micelle concentration. There are two main types of foams -ball foam (microfoam) and polyhedral foam. The characteristics of bulk foam are described by properties such as foam quality, texture, stability, density, surface tension, disjoining pressure, etc. Foam has been used to flush contaminants such as metals, organics, and nonaqueous phase liquids from unsaturated soil. Ball foam, or colloidal gas aphrons, reportedly have been used for soil flushing in contaminated site remediation and was found to be more efficient than surfactant solutions on the basis of weight of contaminant removed per gram of surfactant. Experiments also indicate that the polyhedral foam can be used to enhance soil remediation.The transport of foam in porous media is complicated in that the number of lamellae present governs flow characteristics such as viscosity, relative permeability, fluid distribution, and interactions between fluids. Hence, foam is a non-Newtonian fluid. During transport, foam destruction and formation occur. The net result of the two processes determines the foam texture (i.e., bubble density). Some of the foam may be trapped during transport. According to the impacts of the aqueous and gas flow rates, foam flow generally has two regimes -weak and strong foam. There is also a minimum pressure gradient to initiate foam flow and a critical capillary for foam to be sustained. Similar to other fluids, the transport of foam is described by Darcy's law with the exception that the foam viscosity is variable.Three major approaches to modeling foam transport in porous media are the empirical, semi-empirical, and mechanistic methods. Mechanistic approaches can be complete in principle but may be difficult for obtaining reliable parameters, whereas empirical and semi-emp...

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“…Application of CGAs to separation technology include (i) remediation of soils contaminated with hydrocarbons [4,5], (ii) cleaning of water contaminated with metals [6][7][8] or organic dyes [9,10], (iii) protein separation [11][12][13][14][15] in replacement of a combination of processes including centrifugation, filtration, extraction and chromatography, (iv) cell flotation [16] such as yeast-cells [17], (iv) mineral extraction by flotation [18], (v) algae removal from contaminated waters [1].…”

Section: Motivationsmentioning

confidence: 99%

“…Colloidal gas aphrons have been used for cleaning sand contaminated with oil [5] and could be used for oil recovery when foams are currently being used (see for example…”

Section: Motivationsmentioning

confidence: 99%