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Ian T. Norton – One of the best experts on this subject based on the ideXlab platform.

Santanu Paria – One of the best experts on this subject based on the ideXlab platform.

  • Surfactant enhanced remediation of organic contaminated soil and water
    Advances in Colloid and Interface Science, 2008
    Co-Authors: Santanu Paria
    Abstract:

    Surfactant based remediation technologies for organic contaminated soil and water (groundwater or surface water) is of increasing importance recently. Surfactants are used to dramatically expedite the process, which in turn, may reduce the treatment time of a site compared to use of water alone. In fact, among the various available remediation technologies for organic contaminated sites, Surfactant based process is one of the most innovative technologies. To enhance the application of Surfactant based technologies for remediation of organic contaminated sites, it is very important to have a better understanding of the mechanisms involved in this process. This paper will provide an overview of the recent developments in the area of Surfactant enhanced soil and groundwater remediation processes, focusing on (i) Surfactant adsorption on soil, (ii) micellar solubilization of organic hydrocarbons, (iii) supersolubilization, (iv) density modified displacement, (v) degradation of organic hydrocarbon in presence Surfactants, (vi) partitioning of Surfactants onto soil and liquid organic phase, (vii) partitioning of contaminants onto soil, and (viii) removal of organics from soil in presence of Surfactants. Surfactant adsorption on soil and/or sediment is an important step in this process as it results in Surfactant loss reduced the availability of the Surfactants for solubilization. At the same time, adsorbed Surfactants will retained in the soil matrix, and may create other environmental problem. The bioSurfactants are become promising in this application due to their environmentally friendly nature, nontoxic, low adsorption on to soil, and good solubilization efficiency. Effects of different parameters like the effect of electrolyte, pH, soil mineral and organic content, soil composition etc. on Surfactant adsorption are discussed here. Micellar solubilization is also an important step for removal of organic contaminants from the soil matrix, especially for low aqueous solubility organic contaminants. Influences of different parameters such as single and mixed Surfactant system, hydrophilic and hydrophobic chain length, HLB value, temperature, electrolyte, Surfactant type that are very important in micellar solubilization are reviewed here. Microemulsion systems show higher capacity of organic hydrocarbons solubilization than the normal micellar system. In the case of biodegradation of organic hydrocarbons, the rate is very slow due to low water solubility and dissolution rate but the presence of Surfactants may increase the bioavailability of hydrophobic compounds by solubilization and hence increases the degradation rate. In some cases the presence of it also reduces the rate. In addition to fundamental studies, some laboratory and field studies on removal of organics from contaminated soil are also reviewed to show the applicability of this technology.

  • a review on experimental studies of Surfactant adsorption at the hydrophilic solid water interface
    Advances in Colloid and Interface Science, 2004
    Co-Authors: Santanu Paria, Kartic C Khilar
    Abstract:

    The progresses of understanding of the Surfactant adsorption at the hydrophilic solid–liquid interface from extensive experimental studies are reviewed here. In this respect the kinetic and equilibrium studies involves anionic, cationic, non-ionic and mixed Surfactants at the solid surface from the solution. Kinetics and equilibrium adsorption of Surfactants at the solid–liquid interface depend on the nature of Surfactants and the nature of the solid surface. Studies have been reported on adsorption kinetics at the solid–liquid interface primarily on the adsorption of non-ionic Surfactant on silica and limited studies on cationic Surfactant on silica and anionic Surfactant on cotton and cellulose. The typical isotherm of Surfactants in general, can be subdivided into four regions. Four-regime isotherm was mainly observed for adsorption of ionic Surfactant on oppositely charged solid surface and adsorption of non-ionic Surfactant on silica surface. Region IVof the adsorption isotisotherm is commonly a plateau region above the CMC, it may also show a maximum above the CMC. Isotherms of four different regions are discussed in detail. Influences of different parameters such as molecular structure, temperature, salt concentration that are very important in Surfactant adsorption are reviewed here. Atomic force microscopy study of different Surfactants show the self-assembly and mechanism of adsorption at the solid–liquid interface. Adsorption behaviour and mechanism of different mixed Surfactant systems such as anionic–cationic, anionic– non-ionic and cationic–non-ionic are reviewed. Mixture of surface-active materials can show synergistic interactions, which can be manifested as enhanced surface activity, spreading, foaming, detergency and many other phenomena. D 2004 Elsevier B.V. All rights reserved.

Jeffrey H. Harwell – One of the best experts on this subject based on the ideXlab platform.

  • Surfactant Selection for Optimizing Surfactant-Enhanced Subsurface Remediation
    , 2009
    Co-Authors: Bor-jier Shiau, Joseph D Rouse, David A Sabatini, Jeffrey H. Harwell
    Abstract:

    Regulatory approval for Surfactant enhanced subsurface remediation may be more readily achieved using food grade Surfactants; results of solubilization and microemulsification studies using such Surfactants are presented. For chlorinated organics (PCF, TCE and 1,2-DCE) solubility enhancements with food grade Surfactants were one to two orders of magnitude relative to water alone via solubilization, with similar decreases in remediation times evidenced. Middle phase microemulsions (microemulsification) outperformed solubilization by an additional one to two orders of magnitude for the same Surfactant concentration (up to four orders of magnitude more efficient than water alone). Microemulsification, however, was observed to be a function of Surfactant structure, contaminant composition (including mixed DNAPL phases), and environmental conditions (e.g., aquifer temperature and hardness). Surfactant losses (precipitation, sorption) may hinder the technical and economical viability of the process. High performance Surfactants with indirect food additive status (alkyl diphenyloxide disulfonates) were less susceptibility to losses (precipitation and sorption) than other ionic and nonionic Surfactants while effectively solubilizing PAHs (i.e., naphthalene). It is thus observed that Surfactant enhanced remediation can greatly expedite aquifer restoration and that Surfactant selection is paramount to its technical and economical viability

  • Formulation of ultralow interfacial tension systems using extended Surfactants
    Journal of Surfactants and Detergents, 2006
    Co-Authors: A. Witthayapanyanon, Jeffrey H. Harwell, E. J. Acosta, David A Sabatini
    Abstract:

    Inspired by the concept of lipophilic and hydrophilic linkers, extended Surfactants have been proposed as highly desirable candidates for the formulation of microemulsions with high solubilization capacity and ultralow interfacial tension (IFT), especially for triglyceride oils. The defining characteristic of an extended Surfactant is the presence of one or more intermediate-polarity groups between the hydrophilic head and the hydrophobic tail. Currently only limited information exists on extended Surfactants; such knowledge is especially relevant for cleaning and separation applications where the cost of the Surfactant and environmental regulations prohibit the use of concentrated Surfactant solutions. In this work, we examine Surfactant formulations for a wide range of oils using dilute solutions of the extended Surfactant classes sodium alkyl polypropyleneoxide sulfate (R-(PO)_ x −SO_4Na), and sodium alkyl polypropyleneoxide-polyethyleneoxide sulfate (R-(PO)_ y -(EO)_ z −SO_4Na). The IFT of these systems was measured as a function of electrolyte and Surfactant concentration for polar and nonpolar oils. The results show that these extended Surfactant systems have low critical micelle concentrations (CMC) and critical microemulsion concentrations (CμC) compared with other Surfactants. We also found that the unique structure of these extended Surfactants allows them to achieve ultralow IFT with a wide range of oils, including highly hydrophobic oils (e.g., hexadecane), triolein, and vegetable oils, using only ppm levels of these extended Surfactants. It was also found that the introduction of additional PO and EO groups in the extended Surfactant yielded lower IFT and lower optimum salinity, both of which are desirable in most formulations. Based on the optimum formulation conditions, it was found that the triolein sample used in these experiments behaved as a very polar oil, and all other vegetable oils displayed very hydrophobic behavior. This unexpected triolein behavior is suspected to be due to uncharacterized impurities in the triolein sample, and will be further evaluated in future research.

  • Surfactants: Surfactant Adsorption in Porous Media
    Surfactants, 2000
    Co-Authors: Laura L. Wesson, Jeffrey H. Harwell
    Abstract:

    An overview of some of the significant findings of Surfactant adsorption research is presented. Subjects include the importance of Surfactant adsorption in petroleum applications, some history of Surfactant adsorption research, the mechanisms which have been proposed to explain observed adsorption behavior, and a review of several significant Surfactant adsorption studies. The emphasis of this review is understanding the mechanisms of Surfactant adsorption as they relate to applications of Surfactants in petroleum processes. Introduction Surfactants have a variety of applications in the petroleum industry, and Surfactant adsorption is a consideration in any application where Surfactants come in contact with a solid surface. In enhanced or improved oil recovery (EOR or IOR) Surfactants can be used in classic micellar/polymer (Surfactant) flooding, alkaline/Surfactant/polymer (ASP) flooding or in foams for mobility control or blocking and diverting. Surfactants can act in several ways to enhance oil production: by reducing the interfacial tension between oil trapped in small capillary pores and the water surrounding those pores, thus allowing the oil to be mobilized; by solubilizing oil (some micellar systems); by forming emulsions of oil and water (alkaline methods); by changing the wettability of the oil reservoir (alkaline methods) or by simply enhancing the mobility of the oil. In selecting a suitable Surfactant for any EOR application, one of the criteria for economic success is minimizing Surfactant loss to adsorption.

David A Sabatini – One of the best experts on this subject based on the ideXlab platform.

  • Adsorption, Desorption and Adsolubilization Properties of Mixed Anionic Extended Surfactants and a Cationic Surfactant
    Journal of Surfactants and Detergents, 2012
    Co-Authors: Donyaporn Panswad, David A Sabatini, Sutha Khaodhiar
    Abstract:

    Anionic and cationic Surfactant mixtures exhibit desirable synergism, but are limited by their tendency to form precipitates. This research evaluates the adsorption, adsolubilization and desorption of mixtures of carboxylate-based anionic extended Surfactants and a pyridinium-based cationic Surfactant. The mixture of cetylpyridinium chloride (CPC), selected as the cationic Surfactant, with four anionic extended Surfactants were studied. The anionic Surfactants studied were alkyl propoxylated ethoxylated carboxylate with average number of carbon chain length of 16 and 17 or 16 and 18 with 4 mol of propylene oxide groups and either 2 or 5 mol of ethylene oxide groups. The adsorption of anionic extended and cationic Surfactant mixtures onto a negatively charged metal oxidoxide surface (silica dioxide) was evaluated. The adsolubilization of phenylethanol, styrene and ethylcyclohexane were evaluated for these mixed Surfactant systems. The desorption potential of individual and mixed Surfactant systems was also evaluated by varying the number of washing (desorption) steps. It was found that the plateau adsorption of mixed anionic extended Surfactant and cationic Surfactant occurred at lower Surfactant concentration than that of the CPC alone, although the maximum adsorption capacity of CPC was not enhanced in our mixed Surfactant systems. Adsolubilization capacities of these mixed Surfactant systems are higher than that of the individual Surfactant system. For desorption studies, these mixed Surfactant systems showed lower stability than the individual Surfactant system.

  • Mechanistic Studies of Particulate Soil Detergency: I. Hydrophobic Soil Removal
    Journal of Surfactants and Detergents, 2012
    Co-Authors: Sureeporn Rojvoranun, Chairat Chadavipoo, Wikanda Pengjun, Sumaeth Chavadej, John F. Scamehorn, David A Sabatini
    Abstract:

    The mechanism of particulate soil detergency using aqueous Surfactant systems is not well understood. In this research, carbon black (model hydrophobic soil) removal from a hydrophilic (cotton) and hydrophobic (polyester) fabric is studied using anionic, nonionic, and cationic Surfactants. The zeta potential, solid/liquid spreading pressure, contact angle and Surfactant adsorption of both soil and fabric are correlated to detergency over a range of Surfactant concentrations and pH levels. Electrostatic repulsion between fabric and soil is generally found to be the dominant mechanism responsible for soil removal for all Surfactants and fabrics. Steric effects due to Surfactant adsorption are also important for nonionic Surfactants for soil detachment and antiredeposition. Solid/liquid interfacial tension reduction due to Surfactant adsorption also aids in detergency in cationic Surfactant systems. Wettability is not seen as being an important factor and SEM photos show that entrapment of soil in the fabric weave is not significant; the particles are only attached to the fabric surface. Anionic Surfactants perform best, then nonionic Surfactants. Cationic Surfactants exhibit poor detergency which is attributed to low Surfactant rinseability.

  • Effect of Ionic Head Group on Admicelle Formation by Polymerizable Surfactants
    Journal of Surfactants and Detergents, 2009
    Co-Authors: Emma Asnachinda, Sutha Khaodhiar, David A Sabatini
    Abstract:

    One of the problems of using Surfactant-modified adsorbents in a Surfactant-based adsorption process is loss of Surfactant because of desorption. Recently, polymerizable Surfactants have been used to minimize Surfactant losses by polymerization of the Surfactant admicellar structure to help secure it to the solid oxide surface. In this study, adsorption of polymerizable cationic gemini Surfactant was used to form polymerized bilayers on silica. UV light was used to irradiate and initiate the polymerization process. Surfactant adsorption and desorption were evaluated to compare the efficiency of polymerized and non-polymerized Surfactants using gemini and conventional Surfactants, respectively. Results demonstrate that the increased stability of the polymerized Surfactant-modified surface can reduce the desorption of Surfactant from the surface, thereby improving operating characteristics of the Surfactant-modified media (e.g., maintaining adsolubilization potential, dispersion stability, etc.).

R Pichot – One of the best experts on this subject based on the ideXlab platform.

  • competitive adsorption of Surfactants and hydrophilic silica particles at the oil water interface interfacial tension and contact angle studies
    Journal of Colloid and Interface Science, 2012
    Co-Authors: R Pichot, Fotios Spyropoulos, Ian T. Norton
    Abstract:

    Abstract The effect of Surfactants’ type and concentration on the interfacial tension and contact angle in the presence of hydrophilic silica particles was investigated. Silica particles have been shown to have an antagonistic effect on interfacial tension and contact angle in the presence of both W/O and O/W Surfactants. Silica particles, combined with W/O Surfactant, have no effect on interfacial tension, which is only dictated by the Surfactant concentration, while they strongly affect interfacial tension when combined with O/W Surfactants. At low O/W Surfactant, both particles and Surfactant are adsorbed at the interface, modifying the interface structure. At higher concentration, interfacial tension is only dictated by the Surfactant. By increasing the Surfactant concentration, the contact angle that a drop of aqueous phase assumes on a glass substrate placed in oil media decreases or increases depending on whether the Surfactant is of W/O or O/W type, respectively. This is due to the modification of the wettability of the glass by the oil or water induced by the Surfactants. Regardless of the Surfactant’s type, the contact angle profile was dictated by both particles and Surfactant at low Surfactant concentration, whereas it is dictated by the Surfactant only at high concentration.

  • Competitive adsorption of Surfactants and hydrophilic silica particles at the oil–water interface: Interfacial tension and contact angle studies
    Journal of Colloid and Interface Science, 2012
    Co-Authors: R Pichot, Fotios Spyropoulos, Ian T. Norton
    Abstract:

    Abstract The effect of Surfactants’ type and concentration on the interfacial tension and contact angle in the presence of hydrophilic silica particles was investigated. Silica particles have been shown to have an antagonistic effect on interfacial tension and contact angle in the presence of both W/O and O/W Surfactants. Silica particles, combined with W/O Surfactant, have no effect on interfacial tension, which is only dictated by the Surfactant concentration, while they strongly affect interfacial tension when combined with O/W Surfactants. At low O/W Surfactant, both particles and Surfactant are adsorbed at the interface, modifying the interface structure. At higher concentration, interfacial tension is only dictated by the Surfactant. By increasing the Surfactant concentration, the contact angle that a drop of aqueous phase assumes on a glass substrate placed in oil media decreases or increases depending on whether the Surfactant is of W/O or O/W type, respectively. This is due to the modification of the wettability of the glass by the oil or water induced by the Surfactants. Regardless of the Surfactant’s type, the contact angle profile was dictated by both particles and Surfactant at low Surfactant concentration, whereas it is dictated by the Surfactant only at high concentration.