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Relevant bibliographies by topics / Single surfactant

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Academic literature on the topic 'Single surfactant'

Author: Grafiati

Published: 18 May 2024

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Journal articles on the topic "Single surfactant"

1

Tian, Maozhang, Fan Zhang, Lu Wang, Xing Dong, Lifei Zhang, and Xia Guo. "Activity of Polyphenoloxidase in red Fuji Apples Promoted with Cationic Surfactant – Role of Surfactant Structure." Tenside Surfactants Detergents 58, no. 5 (September 1, 2021): 383–93. http://dx.doi.org/10.1515/tsd-2020-2322.

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Abstract In this study, we observed the activity of polyphenoloxidase (PPO) in red Fuji apples in the presence of single-chained surfactants (including cetyl trimethyl ammonium bromide (CTAB), and dodecyl trimethyl ammonium bromide (DTAB)) and gemini surfactants (pentamethylene-α,ω-bis(dodecyl dimethyl ammonium bromide), octamethylene-α,ω-bis(dodecyl dimethyl ammonium bromide, dodecamethylene-α,ω-bis(dodecyl dimethyl ammonium bromide), pentamethylene-α,ω-bis(cetyl dimethyl ammonium bromide), and octamethylene-α,ω-bis(cetyl dimethyl ammonium bromide)). It was found that all these surfactants enhanced the activity of PPO in a wide range of temperature at low content. When PPO was denatured by incubating at high temperature, the surfactants caused reactivation of PPO. Compared to the single-chained surfactants, the gemini surfactants increased PPO activity at a much lower concentration. Moreover, the single-chained surfactant and the gemini surfactant acted together to further increase PPO activity, and the synergistic effect reduced the amount of surfactant used. In addition, the Michaelis-Menten constant for PPO did not change in the presence of the surfactants, suggesting the active site should remain well with the surfactants.

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Wang, Ruiguo, Xinxin Xu, Xiaodi Shi, Junjie Kou, Hongjian Song, Yuxiu Liu, Jingjing Zhang, and Qingmin Wang. "Promoting Efficacy and Environmental Safety of Pesticide Synergists via Non-Ionic Gemini Surfactants with Short Fluorocarbon Chains." Molecules 27, no. 19 (October 10, 2022): 6753. http://dx.doi.org/10.3390/molecules27196753.

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Improving the utilization rate of pesticides is key to achieve a reduction and synergism, and adding appropriate surfactant to pesticide preparation is an effective way to improve pesticide utilization. Fluorinated surfactants have excellent surface activity, thermal and chemical stability, but long-chain linear perfluoroalkyl derivatives are highly toxic, obvious persistence and high bioaccumulation in the environment. Therefore, new strategies for designing fluorinated surfactants which combine excellent surface activity and environmental safety would be useful. In this study, four non-ionic gemini surfactants with short fluorocarbon chains were synthesized. The surface activities of the resulting surfactants were assessed on the basis of equilibrium surface tension, dynamic surface tension, and contact angle. Compared with their monomeric counterparts, the gemini surfactants had markedly lower critical micelle concentrations and higher diffusivities, as well as better wetting abilities. We selected a single-chain surfactant and a gemini surfactant with good surface activities as synergists for the glyphosate water agent. Both surfactants clearly improved the efficacy of the herbicide, but the gemini surfactant had a significantly greater effect than the single-chain surfactant. An acute toxicity test indicated that the gemini surfactant showed slight toxicity to rats.

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SMIT, B., P. A. J. HILBERS, and K. ESSELINK. "COMPUTER SIMULATIONS OF SURFACTANT SELF ASSEMBLY." International Journal of Modern Physics C 04, no. 02 (April 1993): 393–400. http://dx.doi.org/10.1142/s0129183193000422.

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A simple oil/water/surfactant model is used to study the self-assembly of surfactants. The model contains only the most obvious elements: oil and water do not mix, and a surfactant is an amphiphilic molecule, i.e. one side of the molecule likes oil but dislikes water, the other side likes water but dislikes oil. Computer simulations on large oil/water/surfactant systems were performed on a network of 400 transputers using a parallel molecular dynamics algorithm. The simulations yield a complete micellar size distribution function. Furthermore, we observe (equilibrium) dynamical processes such as the entering of single surfactants into micelles, single surfactants leaving micelles, the fusion of two micelles, and the slow breakdown of a micelle.

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Desai, Tejas R., and Sharad G. Dixit. "Adsorption from Mixtures of Cationic/Non-Ionic Surfactants on to a Polystyrene Surface." Adsorption Science & Technology 15, no. 5 (May 1997): 391–405. http://dx.doi.org/10.1177/026361749701500507.

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The adsorption of cetyltrimethylammonium bromide (CTAB) and nonyl phenyl ethoxylates (NP-n, where n = 13, 20 and 30) on to polystyrene powder has been studied. Concentrations of surfactant solutions ranging from below CMC to well above CMC were investigated. In a single surfactant system, only the cationic surfactant (CTAB) was found to adsorb appreciably while nonionic surfactants showed negligible adsorption. In mixed surfactant systems, the cationic surfactant was found to induce significant co-adsorption of non-ionic surfactants. The increased adsorption of non-ionic surfactants has been attributed to the formation of non-ideal mixed hemimicelles due to intercomponent lateral interactions. However, non-ionic surfactants with longer hydrophilic chains did not form mixed hemimicelles with CTAB. In general, zeta potential measurements support the adsorption results.

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Abdel-Rahem, Rami A., Sana Niaz, Abdelmnim M. Altwaiq, Muayad Esaifan, Mohammad Bassam Al Bitar, and Abeer Al Bawab. "Synergistic interaction between sodium dodecyl benzene sulfonate (SDBS) and N,N-dimethyldodecan-1-amine oxide (DDAO) and their adsorption onto activated charcoal and Jordanian natural clay." Tenside Surfactants Detergents 59, no. 2 (February 28, 2022): 144–58. http://dx.doi.org/10.1515/tsd-2021-2395.

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Abstract Solutions of sodium dodecyl benzene sulfonate (SDBS) and N,N-dimethyldodecan-1-amine oxide (DDAO) with mole fractions of 0.00, 0.25, 0.50, 0.75 and 1.00 were prepared and their surface tension was measured as a function of total surfactant concentration. The critical micelle concentration (CMC) values of these mixed solutions were also determined. The minimum area occupied by a surfactant molecule at air/water interface was calculated for single and binary surfactant mixtures. A pronounced synergistic interaction between SDBS and DDAO was detected. The surface tension and CMC-values of SDBS/DDAO mixtures are significantly lower than those of the single surfactant. The mixed system of SDBS/DDAO exhibits a highly negative interaction parameter (β = −10.6) according to regular solution model, and is found to fulfill the condition of Hua and Rosen, indicting a strong synergistic interaction between the two surfactants. The contact angle measurements show the wettability of the surfactant mixture onto polyethylene substrate is higher than of the respective single surfactant. In addition, the adsorption of SDBS and DDAO or their mixtures on 1.0% activated carbon and 5.0% Jordanian natural clay (JNC), respectively, was investigated using the depletion method. The individual surfactants were found to adsorb to a considerable extent on activated carbon, and a slightly higher adsorption tendency was even measured for mixed SDBS/DDAO surfactant systems. Although no SDBS molecules adsorbed on JNC, adsorption was observed for solutions containing DDAO and SDBS/DDAO surfactants. The improvement in wettability and adsorption of SDBS/DDAO surfactants at the air/water and solid/water interfaces is directly related to the synergistic interaction between the two surfactants.

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Mucic, Nenad, Jelena Skrbic, Sandra Bucko, Lidija Petrovic, Jaroslav Katona, Valentin B. Fainerman, Eugene V. Aksenenko, Emanuel Schneck, and Reinhard Miller. "Adsorption of Equimolar Mixtures of Cationic and Anionic Surfactants at the Water/Hexane Interface." Colloids and Interfaces 5, no. 1 (December 24, 2020): 1. http://dx.doi.org/10.3390/colloids5010001.

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In mixed solutions of anionic and cationic surfactants, called catanionics, ion pairs are formed which behave like non-ionic surfactants with a much higher surface activity than the single components. In equimolar mixtures of NaCnSO4 and CmTAB, all surface-active ions are paired. For mixtures with n + m = const, the interfacial properties are rather similar. Catanionics containing one long-chain surfactant and one surfactant with medium chain length exhibit a strong increase in surface activity as compared with the single compounds. In contrast, catanionics of one medium- and one short chain surfactant have a surface activity similar to that of the medium-chain surfactant alone. Both the Frumkin model and the reorientation model describe the experimental equilibrium data equally well, while the adsorption kinetics of the mixed medium- and short-chain surfactants can be well described only with the reorientation model.

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Zhang, Yongmin, Zhiqiang Chen, and Yong Zhao. "Viscoelastic micellar solution formed by a Se-based ionic liquid surfactant and its response to redox changes." Physical Chemistry Chemical Physics 21, no. 27 (2019): 14734–44. http://dx.doi.org/10.1039/c9cp01256g.

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The incorporation of a Se atom endows the surfactants with redox-sensitivity, and that its site plays a crucial role both in single surfactant solution and viscoelastic micellar solution formed by surfactant and NaSal.

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Walker, S., E. Naranjo, S. Chiruvolu, and J. Zasadzinski. "TEM investigations of self-assembly through physical synthesis." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 436–37. http://dx.doi.org/10.1017/s0424820100169912.

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A novel way of enlarging the realm of surfactant solution microstructure is the "physical synthesis" of new microstructures and surfactant-templated materials by mixing simple surfactants or surfactant and inorganic and ionic species. Mixing can often produce properties not possessed by any one species alone. As we have recently shown, mixtures of single-tailed cationic and anionic surfactants associate in solution to form a quasi-double-tailed catanionic surfactant that forms bilayers rather than the simple micelles each species would form on its own. Mixed surfactant systems apparently produce new microstructures by altering the intermolecular and interaggregate forces in ways impossible for single component systems. In addition to spontaneous vesicles, we have found other new microstructures including dilute lamellar and L3 phases depending on the details of the surfactant mixture. Surfactant interactions with ionic species also play an important role in the in synthesis of a new M41S family of mesoporous silicas, and are likely to be important in the templating of biominerals at interfaces. By understanding the molecular and chemical basis of these interactions, we can begin to tailor new microstructured and/or biomimetic materials by controlling surfactant aggregation and phase behavior through physical synthesis rather than through much more elaborate chemical synthesis.

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Hassan, Mohammed, Sadeq M. Al-Hazmi, Ibrahim A. Alhagri, Ahmed N. Alhakimi, Adnan Dahadha, Mohammad Al-Dhoun, and Yazan Batineh. "Micellar Catalysis of Chemical Reactions by Mixed Surfactant Systems and Gemini Surfactants." Asian Journal of Chemistry 33, no. 7 (2021): 1471–80. http://dx.doi.org/10.14233/ajchem.2021.23187.

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Micellar catalysis exhibited by mixed surfactant systems and gemini surfactants was reviewed. The review focused on mixed surfactant systems and tried to correlate the changes in the physico-chemical properties of these systems to the variations of their catalytic activities. Mixed surfactant systems are promising as the catalytic efficiency of some single surfactants was significantly enhanced in the presence of other critically selected surfactants. The selection should consider the charge, size, and structures of the head group as well as an appropriate length of hydrocarbon tail. The overall conclusion has arrived the mixed surfactant systems could be a tool by which the reaction rate can be tuned by changing the composition and/or the components’ structures. The higher catalytic activity of gemini surfactants compared to conventional ones, their facile synthesis and liability for structure control made them of superior choice for micellar catalysis.

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Miao, Zong Cheng, Yi Wei Wang, Xing Zhang, Lei Zhang, Zhi Xue Wang, and Yuan Yuan Li. "Antimicrobial Study of Symmetrical Gemini Cationic Surfactant Based on N-Hexadecyldimethylamine." Key Engineering Materials 575-576 (September 2013): 245–48. http://dx.doi.org/10.4028/www.scientific.net/kem.575-576.245.

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Gemini surfactants generally exhibit superior properties to those of their single-chain analogues with a similar chain length and head group, especially for gemini cationic surfactants. Gemini cationic surfactants have recently attracted considerable attention due to the increasing microbial resistance to common quaternary ammonium compounds. A novel symmetrical gemini cationic surfactant based onn-hexadecyldimethylamine was synthesized through epichlorohydrin andn-hexadecyldimethylamine as rude materials. The chemical structure of the product was confirmed using1H-NMR and FT-IR. The minimum inhibitory concentration of the surfactant toescherichia colirises to 100 ppm, and a higher concentration surely contributes to increase its effect, butstaphylococcus aureusis immune to this surfactant.

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Dissertations / Theses on the topic "Single surfactant"

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Bardhan, Soumik. "Physicochemical studies on some self organized assemblies of single and mixed surfactant systems." Thesis, University of North Bengal, 2015. http://hdl.handle.net/123456789/1855.

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Ayewah, Daniel Osagie Oyinkuro. "Characterization of surfactant dispersed single wall nanotube - polystyrene matrix nanocomposite." Thesis, [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1397.

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Barnett, Catherine Margaret Eleanor. "Association of Single Nucleotide Polymorphisms in Surfactant Protein A and D with Otitis Media." The University of Waikato, 2007. http://hdl.handle.net/10289/2338.

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Otitis Media is one of the most common childhood diseases. Recurrent acute otitis media RAOM is characterized by repeated episodes of inflammation of the middle ear in conjunction with middle ear fluid, and often with an inflamed or bulging eardrum. Defective clearance by the Eustachian tube results in mucus build-up and is characteristic of otitis media with effusion (OME). Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, respiratory syncytial virus, and rhinovirus are the most common contributors to otitis media pathogenesis. In New Zealand, OME has been implicated with conductive hearing loss in childhood and has been shown to significantly impact on speech and language development. New Zealand Māori and Polynesian children have displayed significantly higher hearing test failure rates than European-Caucasian children. The collectins, Surfactant Protein (SP)-A and -D are encoded by three genes (SP-A1, SP-A2, and SP-D) and are host defense proteins present in the middle ear and Eustachian tube. Single nucleotide polymorphisms (SNPs) in SP-A1 and SP-A2 have been associated with increased or decreased susceptibility to otitis media, meningococcal disease, and range of respiratory diseases. Using allele-specific primers and real-time PCR with SYBR Green I melting curve analysis, four groups of individuals were genotyped for eleven SP-A1, SP-A2, and SP-D SNPs: European-Caucasian individuals with RAOM/OME; New Zealand Māori/Polynesian individuals with RAOM/OME; individuals with meningococcal disease; and a control group. The computer program, Haploview, was employed to perform χ2 analyses and identify statistically significant associations of alleles/haplotypes with RAOM/OME or meningococcal disease. In the European-Caucasian population, two SP-A1 alleles, one SP-A2 allele, and four haplotypes (CGAGC, 1A3, 1A9, and 1A10) were found to be associated with increased risk of RAOM/OME (P lt; 0.05). Conversely, haplotypes 6A2 and 1A2 were found to be protective against susceptibility to RAOM/OME (P lt; 0.05). In New Zealand Māori and Polynesian individuals, two SP-A1 alleles, three SP-A2 alleles, one SP-D allele, and four haplotypes (6A8, 6A10, 1A3, and 1A10) were found to be associated with increased risk of RAOM/OME (P lt; 0.05). An additional four haplotypes (6A2, 1A0, 1A2, and TA) were determined to be protective against susceptibility to RAOM/OME (P lt; 0.05). However, protective SPA1/SPA2/SPD haplotype 6A2-1A0-TA was significantly under-represented in the New Zealand Māori and Polynesian population (P lt; 0.05). A single allele and haplotype were associated with increased risk of meningococcal disease (P lt; 0.05). The findings of this study confirm that specific genetic variants of SP-A and SP-D are associated with either increased or decreased risk of developing RAOM and/or OME. Furthermore, it was demonstrated that New Zealand Māori and Polynesian individuals appear to exhibit more haplotypes susceptible to RAOM/OME. This may provide a partial explanation for the higher RAOM/OME-related failure rates of hearing tests in New Zealand Māori and Polynesian children. However, there are numerous socio-economic and environmental factors that also contribute to otitis media pathogenesis which were not considered in this study. The effects of the SP-A1, SP-A2, and SP-D alleles and haplotypes on the bacterial/viral binding efficiencies of SP-A and SP-D need to be investigated by further research, using a large population, to confirm the association with susceptibility or resistance with RAOM/OME.

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SAMPATHKUMAR, SETHURAGHAVAN. "INTERFACIAL CHARACTERISTICS AND EBULLIENCE IN AQUEOUS SURFACTANT SOLUTIONS: DYNAMIC SURFACE TENSION AND SINGLE BUBBLE BEHAVIOR." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1109001316.

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Sampathkumar, Sethuraghavan. "Interfacial characteristics and ebulience in aqueous surfactant solutions dynamic surface tension and single bubble behavior /." Cincinnati, Ohio : University of Cincinnati, 2005. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1109001316.

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Wang, Zhiyong, Gang Wang, Haoyuan Qi, Mao Wang, Mingchao Wang, SangWook Park, Huaping Wang, et al. "Ultrathin Two-Dimensional Conjugated Metal-Organic Framework Single-Crystalline Nanosheets Enabled by Surfactant-Assisted Synthesis." Royal Society of Chemistry, 2020. https://tud.qucosa.de/id/qucosa%3A72508.

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Two-dimensional conjugated metal-organic frameworks (2D c-MOFs) have recently emerged for potential applications in (opto-)electronics, chemiresistive sensing, and energy storage and conversion, due to their excellent electrical conductivity, abundant active sites, and intrinsic porous structures. However, developing ultrathin 2D c-MOF nanosheets (NSs) for facile solution-processing and integration into devices remains a great challenge, mostly due to unscalable synthesis, low yield, limited lateral size and low crystallinity. Here, we report a surfactant-assisted solution synthesis toward ultrathin 2D c-MOF NSs, including HHB-Cu (HHB=hexahydroxybenzene), HHB-Ni and HHTP-Cu (HHTP=2,3,6,7,10,11-hexahydroxytriphenylene). For the first time, we achieve single-crystalline HHB-Cu(Ni) NSs featured with a thickness of 4-5 nm (~8-10 layers) and a lateral size of 0.25-0.65 μm², as well as single-crystalline HHTP-Cu NSs with a thickness of ~5.1±2.6 nm (~10 layers) and a lateral size of 0.002-0.02 μm². Benefiting from the ultrathin feature, the synthetic NSs allow fast ion diffusion and high utilization of active sites. As a proof of concept, when serving as a cathode material for Li-ion storage, HHB-Cu NSs deliver a remarkable rate capability (charge within 3 min) and long-term cycling stability (90% capacity retention after 1000 cycles), superior to the corresponding bulk materials and other reported MOF cathodes.

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Pal, Prem, Kazuo Sato, Miguel A. Gosalvez, Yasuo Kimura, Ken-Ichi Ishibashi, Michio Niwano, Hirotaka Hida, Bin Tang, and Shintaro Itoh. "Surfactant Adsorption on Single-Crystal Silicon Surfaces in TMAH Solution: Orientation-Dependent Adsorption Detected by In Situ Infrared Spectroscopy." IEEE, 2009. http://hdl.handle.net/2237/13883.

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Spohr, Reimar. "Ion Tracks for Micro- and Nanofabrication : From Single Channels to Superhydrophobic Surfaces." Doctoral thesis, Uppsala universitet, Materialfysik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-111247.

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A method is described for preset-count irradiations between 1 and 100 ions singling-out individual ions from an ion beam with more than a billion ions arriving per second. The ion tracks are etched in a conductometric system with real-time evaluation of the acquired data. The etch process can be interrupted when reaching a preset channel diameter. Cylindrical channels are obtained by adding surfactants to the etch solution forming a self-assembled barrier between etching medium and polymer. Asymmetric etching of single ion tracks leads to pH sensitive conical pores with diode-like properties. Using etched channels as template, homogeneous and multilayer magnetic single-wires are electrodeposited. The magnetoresistivity of the wires is studied. Single-track applications comprise critical apertures (cylindric, conic, necked), asymmetric pores (pH sensitive, biospecific), Giant Magneto Resistance sensors, and spintronic devices. On the basis of studies with individual ion tracks we tackled tilted multiporous systems such as ion beam lithography with a masked ion beam leading to micro-structures with inclined walls and anisotropic superhydrophobic ion track textures, analogous to biological shingle structures on butterfly wings. We demonstrated qualitatively, that the asymmetry of the texture translates into motion under ultrasonic agitation. This could lead to the development of rotary drives.

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Fennell, John. "The electrochemistry of surfactants on gold single-crystals and of platinum-gold nanorods." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4168/.

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A series of Pt-coated gold nanorod (Au NR) electrocatalysts were prepared. STEM images showed that Pt nanodots grew epitaxially on the Au NR surface. A CO blocking technique was used in order to coat Pt in a more controlled, uniform manner. The nanorods were characterised using UV-visible spectroscopy and, after being immobilised onto a supported glassy carbon electrode, with cyclic voltammetry. The CO blocking technique was crucial in enhancing CO electrooxidation and oxygen reduction reaction activity of the nanorods, not only because of the higher coverage of Pt nanodots but also because of their electrocatalytically more active nature.

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Daful, Asfaw Gezae. "Microscopic modeling of the self assembly of surfactants: shape transitions and critical micelle concentrations." Doctoral thesis, Universitat Rovira i Virgili, 2011. http://hdl.handle.net/10803/33596.

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El CMC, tamaño y forma de micelas son características importantes en la determinación de sus principales propiedades y campos de aplicación. Esta tesis tiene dos partes, las transiciones de forma de las micelas que se trata con "Single chain Field Theory, /SCMFT)" y simulaciones de Monte Carlo. El SCMFT reveló todas las características esenciales de las transiciones de forma esférica a cilíndrica y esférica a disco de las micelas. MC muestra que las transiciones esfera a cilindro se produce a través de una región en que esferas y cilindros coexisten junto con otras formas intermedias.

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Books on the topic "Single surfactant"

1

Hoeft, Carl E. Surfactant adsorption in single component systems. 1992.

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Book chapters on the topic "Single surfactant"

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Jesorka, Aldo, Michal Tokarz, and Owe Orwar. "Single Molecules and Nanoscale Surfactant Networks." In Single Molecules and Nanotechnology, 217–50. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-73924-1_9.

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Naouli, Nabil, and Henri L. Rosano. "Design of Single Surfactant Microemulsion." In ACS Symposium Series, 116–30. Washington, DC: American Chemical Society, 2009. http://dx.doi.org/10.1021/bk-2009-1007.ch007.

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Fujiwara, T., M. Konishi, S. Chida, and H. Maeta. "Factors Affecting the Response to a Postnatal Single Dose of a Reconstituted Bovine Surfactant (Surfactant TA)." In Surfactant Replacement Therapy, 91–107. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-73305-5_11.

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Bloom, B. T. "Human Surfactant and Calf Lung Surfactant Extract: Moderation of Respiratory Distress in Preterm Infants by a Single Prophylactic Dose in a Randomized and Controlled Clinical Trial." In Surfactant Replacement Therapy, 150–57. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-73305-5_19.

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Szönyi, S., A. Cambon, H. J. Watzke, P. Schurtenberger, and E. Wehrli. "Multicomponent Vesicular Aggregates (MCVA): Spontaneous Vesiculation of Perfluorinated Single-Chain Surfactant Mixtures." In Springer Proceedings in Physics, 198–201. Berlin, Heidelberg: Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-84763-9_39.

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Bu, Tor, and Sigurd Ivar Aanonsen. "Simulation for Planning and Interpretation of a Single Well Surfactant and Tracer Test." In North Sea Oil and Gas Reservoirs — III, 277–88. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0896-6_24.

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Clin, B., J. Biais, J. F. Bodet, and P. Lalanne. "Geometrical Features of Single-Phase Microemulsions." In Surfactants in Solution, 139–45. Boston, MA: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4615-7990-8_7.

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Veeralakshmi, Selvakumar, Selvan Nehru, and Sankaralingam Arunachalam. "Role of Hydrophobicity of Some Single- and Double-Chain Surfactant–Cobalt(III) Complexes on the Interaction with Bovine Serum Albumin." In Research Methodology in Chemical Sciences, 17–38. Toronto : Apple Academic Press, 2016.: Apple Academic Press, 2017. http://dx.doi.org/10.1201/9781315366616-2.

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Zielińska, Katarzyna, Jadwiga Pietkiewicz, Jolanta Saczko, and Kazimiera A. Wilk. "Microemulsions Stabilized by Gemini, Dicephalic and Single-Head Single-Tail Sugar Surfactants as Biologically Important Systems: Hemolytic Activity and Cytotoxic Studies." In Trends in Colloid and Interface Science XXIV, 193–96. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-19038-4_35.

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Krafft, Marie Pierre, and Françoise Giulieri. "Stabilizing Colloids with Fluorocarbon-Hydrocarbon Diblocks: Example of Vesicles Made from Single-Chain Fluorinated Surfactants." In Fluorinated Surfaces, Coatings, and Films, 48–56. Washington, DC: American Chemical Society, 2001. http://dx.doi.org/10.1021/bk-2001-0787.ch004.

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Conference papers on the topic "Single surfactant"

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Panthi, Krishna, and Kishore K. Mohanty. "Chemical Flood with a Single Surfactant." In SPE Improved Oil Recovery Conference. SPE, 2022. http://dx.doi.org/10.2118/209385-ms.

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Abstract The goal of this work is to develop alkaline-surfactant-polymer (ASP) formulations for a shallow, clayey sandstone reservoir. Commercially available surfactants were used in the phase behavior study. The gas-oil-ratio (GOR) was low; the phase behavior and coreflood study was conducted with the dead oil. The surfactant formulation systems were tested in tertiary ASP core floods in reservoir rocks. Many surfactant formulations were identified which gave ultralow IFT, but the formulation with only one surfactant (at 0.5 wt% concentration) in presence of one co-solvent was selected for corefloods. The cumulative oil recovery was in the range of 94-96% original oil in place (OOIP) in the corefloods. The surfactant retention was low (0.15 mg/gm of rock) in spite of the high clay content. The study showed that 0.5 PV of ASP slug and 2700 ppm of the polymer were required to make the flood effective. The use of alkali and preflush of the soft brine helped minimize surfactant retention.

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Acosta, Edgar, Brandon Cordeiro, Carol Tan, and Rafael Perez. "Direct assessment of the characteristic curvature (Cc) of single surfactants." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/cvxn6372.

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The conventional method to assess the hydrophilic/lipophilic character of a surfactant within the HLD framework (sigma or Cc) involves the use of numerous phase scans with mixtures of the test surfactant of interest and a reference surfactant that can undergo phase inversion on its own. While this method provides reasonable answers, it requires a multitude of phase behavior studies and it requires making assumptions around the mixing rules and properties of the test surfactant. In this presentation we use the definition of characteristic curvature (Cc) to conduct oil and water solubilization studies and obtain the HLD parameters of test surfactants on their own, without the need for mixtures with a reference surfactant. The implications of using this protocol are discussed, particularly in light of the current form of the HLD equation for ionic surfactants. A comparison of the test-reference protocol vs. the single surfactant (solubilization) protocol is included to understand the roots of the similiraties and differences between the two approaches.

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Bello, Ayomikun, Alexander Rodionov, Anastasia Ivanova, and Alexey Cheremisin. "Synergistic Effects of Binary Surfactant Systems for Enhanced Oil Recovery in Carbonates." In SPE Improved Oil Recovery Conference. SPE, 2024. http://dx.doi.org/10.2118/218271-ms.

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Abstract This study investigates the use of binary surfactant systems for enhancing oil recovery (EOR) in carbonate formations, which have complex surface charges and harsh conditions (high temperature, high salinity) that limit the effectiveness of single surfactants. Binary surfactants form mixed micelles with lower interfacial tension (IFT) and higher solubilization capacity than single surfactants, thus improving their performance and synergism. We measured the critical micelle concentrations (CMCs) of various binary surfactant ratios and applied Rubingh's Regular Solution Theory (RST) to analyze their behavior and interactions. We found that the binary surfactants had lower CMCs than their individual components, which means less surfactant is needed to achieve optimal surface activity, reducing costs and environmental impact. The nonionic surfactant concentration was a key factor for synergism. We also conducted static adsorption and spontaneous imbibition tests to examine the effects of binary surfactants on oil recovery. We observed that the nonionic surfactant reduced the adsorption of the anionic and cationic surfactants by 53% and 28%, respectively, and increased the recovery factor to nearly 60%. Our results demonstrate the potential of binary surfactant systems for EOR in carbonate formations, as well as for CO2 sequestration and filtration optimization.

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Bello, Ayomikun, Alexander Rodionov, Anastasia Ivanova, and Alexey Cheremisin. "Experimental Investigation and Molecular Dynamics of the Fluid-Fluid Interactions Between Binary Surfactant Systems for EOR." In GOTECH. SPE, 2024. http://dx.doi.org/10.2118/219237-ms.

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Abstract This work aims to explore the properties and interactions between binary surfactant systems. We employed a methodology comprising experimental analysis, mathematical modeling, and molecular dynamics simulations. In the experimental study, we examined eight individual surfactants and six binary surfactant systems at various ratios to determine their critical micelle concentrations (CMCs), using reservoir oil and performing experiments at reservoir conditions. Then, Rubingh's Regular Solution Theory (RST) was applied to evaluate interactions within the binary surfactant mixtures. Finally, using molecular dynamics simulations, we characterized the microscopic interactions to comprehend how hydrophilic and hydrophobic parts of the surfactants interact with surrounding media, and how they self-assemble into aggregates such as micelles or bilayers. The key findings of our work showed that the occurrence of synergism or antagonism in lowering the CMC of binary surfactant mixtures depend on both the concentration of the individual surfactant and the type of surfactant used. Nevertheless, we noted a prevalent synergistic phenomenon in all binary surfactant systems, notably influenced by the concentration of the non-ionic surfactant. Increased concentrations of non-ionic surfactants notably enhanced synergistic interactions, fostering lowered CMC values when combined with anionic, cationic, and zwitterionic surfactants. On the other hand, an excessive concentration of cationic surfactants demonstrated relatively ‘weak’ synergistic effects, attributed to their comparatively smaller hydrophobic tail. Moreover, the formation of mixed micelles in binary surfactant systems led to a more negative free energy of micellization, thereby achieving synergistic effects between surfactants and resulting in lower CMC values. This emphasizes the crucial role of surfactant concentration in achieving synergistic outcomes within mixed systems. Generally, binary surfactant systems demonstrated lower CMC values compared to single surfactants, suggesting the potential for their use at lower concentrations to achieve desired interfacial and recovery outcomes, thereby reducing operational costs.

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Saputra, I. Wayan Rakananda, and David S. Schechter. "A Temperature Operating Window Concept for Application of Nonionic Surfactants for EOR in Unconventional Shale Reservoirs." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/206346-ms.

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Abstract Surfactant performance is a function of its hydrophobic tail, and hydrophilic head in combination with crude oil composition, brine salinity, rock composition, and reservoir temperature. Specifically, for nonionic surfactants, temperature is a dominant variable due to the nature of the ethylene oxide (EO) groups in the hydrophilic head known as the cloud point temperature. This study aims to highlight the existence of temperature operating window for nonionic surfactants to optimize oil recovery during EOR applications in unconventional reservoirs. Two nonylphenol (NP) ethoxylated nonionic surfactants with different EO head groups were investigated in this study. A medium and light grade crude oil were utilized for this study. Core plugs from a carbonate-rich outcrop and a quartz-rich outcrop were used for imbibition experiments. Interfacial tension and contact angle measurements were performed to investigate the effect of temperature on the surfactant interaction in an oil/brine and oil/brine/rock system respectively. Finally, a series of spontaneous imbibition experiments was performed on three temperatures selected based on the cloud point of each surfactant in order to construct a temperature operating window for each surfactant. Both nonionic surfactants were observed to improve oil recovery from the two oil-wet oil/rock system tested in this study. The improvement was observed on both final recovery and rate of spontaneous imbibition. However, it was observed that each nonionic surfactant has its optimum temperature operating window relative to the cloud point of that surfactant. For both nonionic surfactants tested in this study, this window begins from the cloud point of the surfactant up to 25°F above the cloud point. Below this operating window, the surfactant showed subpar performance in increasing oil recovery. This behavior is caused by the thermodynamic equilibrium of the surfactant at this temperature which drives the molecule to be more soluble in the aqueous-phase as opposed to partitioning at the interface. Above the operating window, surfactant performance was also inferior. Although for this condition, the behavior is caused by the preference of the surfactant molecule to be in the oleic-phase rather than the aqueous-phase. One important conclusion is the surfactant achieved its optimum performance when it positions itself on the oil/water interface, and this configuration is achieved when the temperature of the system is in the operating window mentioned above. Additionally, it was also observed that the 25°F operating window varies based on the characteristic of the crude oil. A surfactant study is generally performed on a single basin, with a single crude oil on a single reservoir temperature or even on a proxy model at room temperature. This study aims to highlight the importance of applying the correct reservoir temperature when investigating nonionic surfactant behavior. Furthermore, this study aims to introduce a temperature operating window concept for nonionic surfactants. This work demonstrates that there is not a "one size fits all" surfactant design.

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Chang, Leonard Yujya, Zhitao Li, Haishan Luo, and Gary Arnold Pope. "Fundamental Improvements in Modeling Surfactant Behavior in Reservoir Simulators." In SPE Improved Oil Recovery Conference. SPE, 2022. http://dx.doi.org/10.2118/209423-ms.

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Abstract Most chemical EOR formulations are surfactant mixtures, but these mixtures are usually modeled as a single pseudo-component in reservoir simulators. However, the composition of an injected surfactant mixture changes as it flows through a reservoir. For example, as the mixture is diluted, the CMC changes, which changes both the adsorption of each surfactant component and the microemulsion phase behavior. Modeling the physical chemistry of surfactant mixtures in a reservoir simulator was found to be more significant than anticipated and is needed to make accurate reservoir-scale predictions of both chemical floods and the use of surfactants to stimulate shale wells.

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Xiong, Ding, Shehzad Ahmed, Waleed Alameri, and Emad W. Al-Shalabi. "Experimental Evaluation of Amphoteric and Switchable Surfactants for Improving Foam Performance Under Harsh Reservoir Conditions." In Offshore Technology Conference Asia. OTC, 2022. http://dx.doi.org/10.4043/31334-ms.

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Abstract Foam injection is designed to reduce the effects of high reservoir heterogeneities and fluid viscosity contrasts during gas flooding, and hence, improve sweep efficiency. However, harsh reservoir conditions in the Middle Eastern reservoirs pose a serious problem to foam stability, leading to a poor mobility control for foam injection. In this study, different surfactant types and their combinations were tested to screen and optimize foam performance in harsh salinity (20 wt%) at high pressure and high temperature (HPHT) conditions (1000 psi and 80 °C) based on series of bulk foam experiments. For this purpose, different commercial amphoteric and amine-based switchable surfactants were utilized and their compatibility in 20 wt% brine were ensured at HPHT conditions. Initial screening was performed by conducting series of foam stability and foaming ability tests at high temperature. The surface tension and surfactant solution rheology tests were performed to analyze foam behavior. The mixtures of amphoteric and amine-based surfactants were then investigated to improve bulk foam performance. Foam stability and foam texture at different foam qualities under HPHT conditions were also studied. Bulk foam experiments showed that betaine (B-1235) surfactant outperformed other surfactant types through achieving the highest foam generation with excellent foam stability performance. Betaine foam endurance was found to be comparable to that of viscoelastic diamine surfactant. However, poor foam generation was observed when diamine was used as a single surfactant. The optimum concentration for betaine surfactant was found to be 0.25 wt%. A mixture of betaine and amine-based surfactant improved the latter foam properties and its performance was found to be higher than that of single surfactant. The foam stability of mixed surfactant was approximately 8 folds higher than that of single amine-based surfactant. Furthermore, foam texture directly controls foam decay profile, and the optimum foam quality based on static pressurized foam cell test was found to be 90% due to the formation of uniform and closely packed bubbles. This research identified high performing individual as well as a mixed surfactant systems for designing foam EOR projects for Middle Eastern harsh reservoir conditions.

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Kurimoto, Ryo, Kosuke Hayashi, and Akio Tomiyama. "Numerical Simulation of Bubbles Contaminated With Soluble Surfactant." In ASME-JSME-KSME 2011 Joint Fluids Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajk2011-04019.

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An interface tracking method for predicting motions of bubbles contaminated with soluble surfactants is presented. A level set method is utilized to track the interface. Transportations of surfactants in the bulk liquid and those at the interface are taken into account. The amount of adsorption and desorption is evaluated by using the Frumkin & Levich model. Simulations of bubbles contaminated with soluble surfactants are carried out, i.e., single air bubbles rising through stagnant water, Taylor bubbles in a vertical pipe filled with water, and a wobbling bubble in a vertical duct. As a result, the following conclusions are obtained: (1) the increase in drag coefficients of spherical bubbles due to the presence of surfactant, i.e. Marangoni effect, is well predicted, (2) surfactants mainly accumulate at the rear edge of a Taylor bubble and the Marangoni effect is very small in the nose region at high Eo¨tvo¨s and low Morton numbers, and therefore, the effects of surfactant on the bubble rising velocity are small in low viscosity systems, and (3) the surfactant concentration is low in the top region of a wobbling bubble, whereas it is high in the bottom region. The peak concentration appears at the side edge of the bubble and the location of the peak concentration moves with the bubble and wake movements.

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Razak, A. A. A., S. Zainal, R. Z. K. Bahrim, I. C. Hsia, N. Razali, M. F. Zaidin, N. N. Zulkarnain, and M. I. M. Amir. "Foam-Assisted Water Alternating Gas (FAWAG) Injection in Offshore Malaysia Fields: A Single Formulation Approach for Enhanced Oil Recovery." In International Petroleum Technology Conference. IPTC, 2024. http://dx.doi.org/10.2523/iptc-24497-ms.

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Abstract This study explores the development of a unified foam formulation for Foam-Assisted Water Alternating Gas (FAWAG) injection in offshore Malaysia fields. The goal is to improve sweep efficiency and enhance oil recovery by utilizing foam as a mobility control agent. The research focuses on optimizing the FAWAG process for offshore Malaysia's reservoir conditions. Laboratory experiments evaluated various foam surfactants to enhance the Water Alternating Gas (WAG) process, with three promising formulations identified. These formulations underwent rigorous testing using native sandstone core samples at high temperatures to assess their applicability in fields with lower reservoir temperatures. The results indicated that the surfactants initially increased differential pressure during the WAG cycle due to their low relative permeability. However, as they displaced gas and advanced through the core, the pressure gradually decreased. Increasing the injection rate improved foam generation, ensuring adequate foam formation. Post-flush injection with synthetic brine confirmed the effectiveness of the foam surfactant formulation. This study represents a groundbreaking effort to develop a regionally applicable foam surfactant for FAWAG injection in offshore Malaysia fields.

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Hetsroni, G., and A. Mosyak. "Bubble Growth in Surfactant Solutions." In 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-23091.

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The presence of surfactant additives in water was found to enhance significantly the boiling heat transfer. The objective of the present investigation was to compare the bubble growth in water to that of a surfactant solution with negligible environmental impact. The study was conducted to clarify the effect of the heat flux on the dynamics of bubble nucleation. The bubble growth under condition of pool boiling in water and surfactant solutions was studied using high speed video technique. The bubble generation was studied on a horizontal flat surface; where the natural roughness of the surface was used to produce the bubbles. At heat flux of q= 10 kW/m2 the life-time and the volume of bubble growth in surfactant solution did not differ significantly from those of water. The time behavior of the contact angle of bubble growing in surfactant solution is qualitatively similar to that of water. At a heat flux of q= 50 kW/m2, boiling in surfactant solution, when compared with that of pure water, was observed to be more vigorous. Surfactant promotes activation of nucleation sites; the bubbles appeared in a cluster mode; the life-time of each bubble in the cluster is shorter than that of a single water bubble. The detachment diameter of water bubble increases with increasing heat flux, whereas analysis of bubble growth in surfactant solution reveals the opposite effect: the detachment diameter of the bubble decreases with increasing heat flux. Natural convection boiling of water and surfactants at atmospheric pressure in narrow horizontal annular channels was studied experimentally in the range of Bond numbers Bo = 0.185–1.52. The flow pattern was visualized by high-speed video recording to identify the different regimes of boiling of water and surfactants. The channel length was 24mm and 36mm, the gap size was 0.45, 1.2, 2.2, and 3.7mm. The heat flux was in the range of 20–500 kW/m2, the concentration of surfactant solutions was varied from 10 to 600 ppm. For water boiling at Bond numbers Bo<1 the CHF in restricted space is lower than that in unconfined space. This effect increases with increasing the channel length. For water at Bond number Bo = 1.52, boiling can almost be considered as unconfined. Additive of surfactant led to enhancement of heat transfer compared to water boiling in the same gap size, however, this effect decreased with decreasing gap size. For the same gap size, CHF in surfactant solutions was significantly lower than that in water. Hysteresis was observed for boiling in degraded surfactant solutions.

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Reports on the topic "Single surfactant"

1

Istok, Jonathan D., and Field, Jennifer, A. In Situ, Field Scale Evaluation of Surfactant Enhanced DNAPL Recovery Using a Single-Well, Push-Pull Test. Office of Scientific and Technical Information (OSTI), June 1999. http://dx.doi.org/10.2172/828071.

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Istok, J. D., and J. A. Field. In situ, field-scale evaluation of surfactant-enhanced DNAPL recovery using a single-well, ``push-pull'' test. Office of Scientific and Technical Information (OSTI), October 1999. http://dx.doi.org/10.2172/750966.

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Istok, J. D., and J. A. Field. In situ, field scale evaluation of surfactant enhanced DNAPL recovery using a single-well, push-pull test. 1997 annual progress report. Office of Scientific and Technical Information (OSTI), January 1998. http://dx.doi.org/10.2172/13616.

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Istok, J. D. In situ, field scale evaluation of surfactant enhanced DNAPL recovery using a single-well, push-pull test. 1998 annual progress report. Office of Scientific and Technical Information (OSTI), June 1998. http://dx.doi.org/10.2172/13617.

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Weiss. L52296 Smart Gas Using Chemicals To Improve Gas Deliverability Phase II. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), March 2009. http://dx.doi.org/10.55274/r0010658.

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The objective of this effort was to demonstrate in the field the new wettability altering technology developed in the laboratory during Phase 1. Reservoir cores from three gas storage facilities including sandstone and dolomite reservoirs were used to evaluate the two surfactants. The imbibition and core flood tests showed that gas deliverability was improved in surfactant-treated sandstone cores. It was concluded that the aquifer storage facilities are candidates for field testing. Results from Phase I provided the foundation for this Phase II project. The Waverly Storage Facility operated by Southern Union/Panhandle Energy was selected as the site for a field test of the surfactant process. Waverly is an 1800-ft sandstone aquifer gas storage reservoir located near Springfield, lllinois. Expansion and contraction of a spherical gas bubble provided pressure support as gas was injected and withdrawn from 37 individual wells. Three wells were selected for treatment with 1000 bbl of ~4% surfactant solution. An additional three nearby wells were selected as control wells. A field mixing procedure similar to that used in the laboratory to avoid phase separation of the microemulsion was developed and successfully used during the third week of October 2007 when the wells were treated. Rates and pressures were measured at the wellhead; fluid levels were not recorded. Since the initial rate-pressure data collected during the project year including the well treatments were sparse, it was decided to extend the project to the end of 2008 to acquire more field data.

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Katan, Jaacov, and Michael E. Stanghellini. Clinical (Major) and Subclinical (Minor) Root-Infecting Pathogens in Plant Growth Substrates, and Integrated Strategies for their Control. United States Department of Agriculture, October 1993. http://dx.doi.org/10.32747/1993.7568089.bard.

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In intensive agriculture, harmful soilborne biotic agents, cause severe damage. These include both typical soilborne (clinical) major pathogens which destroy plants (e.g. Fusarium and Phytophthora pathogens), and subclinical ("minor") pathogens (e.g. Olpidium and Pythium). The latter cause growth retardation and yield decline. The objectives of this study were: (1) To study the behavior of clinical (major) and subclinical (minor) pathogens in plant growth substrate, with emphasis on zoosporic fungi, such as Pythium, Olipidium and Polymyxa. (2) To study the interaction between subclinical pathogens and plants, and those aspects of Pythium biology which are relevant to these systems. (3) To adopt a holistic-integrated approach for control that includes both eradicative and protective measures, based on a knowledge of the pathogens' biology. Zoospores were demonstrated as the primary, if not the sole propagule, responsible for pathogen spread in a recirculating hydroponic cultural system, as verified with P. aphanidermatum and Phytophthora capsici. P. aphanidermatum, in contrast to Phytophthora capsici, can also spread by hyphae from plant-to-plant. Synthetic surfactants, when added to the recirculating nutrient solutions provided 100% control of root rot of peppers by these fungi without any detrimental effects on plant growth or yield. A bacterium which produced a biosurfactant was proved as efficacious as synthetic surfactants in the control of zoosporic plant pathogens in the recirculating hydroponic cultural system. The biosurfactant was identified as a rhamnolipid. Olpidium and Polymyxa are widespread and were determined as subclinical pathogens since they cause growth retardation but no plant mortality. Pythium can induce both phenomena and is an occasional subclinical pathogen. Physiological and ultrastructural studies of the interaction between Olpidium and melon plants showed that this pathogen is not destructive but affects root hairs, respiration and plant nutrition. The infected roots constitute an amplified sink competing with the shoots and eventually leading to growth retardation. Space solarization, by solar heating of the greenhouse, is effective in the sanitation of the greenhouse from residual inoculum and should be used as a component in disease management, along with other strategies.

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Chefetz, Benny, Baoshan Xing, and Yona Chen. Interactions of engineered nanoparticles with dissolved organic matter (DOM) and organic contaminants in water. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7699863.bard.

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Background: Engineered carbon nanotubes (CNTs) are expected to be increasingly released into the environment with the rapid increase in their production and use. The discharged CNTs may interact with coexisting contaminants and subsequently change environmental behaviors and ecological effects of both the CNTs themselves and the contaminants. Dissolved organic matter (DOM) plays a critical role in the transport of CNTs in the aquatic environment, affecting both CNT's surface properties through adsorption, and its colloidal stability in solution. Therefore, CNT-bound DOM complexes may interact with coexisting contaminants, thus affecting their environmental fate. With increasing production and use of CNTs, there is an increasing risk that humans could be exposed to CNTs mainly through ingestion and inhalation. Since CNTs can be carriers of contaminants due to their high adsorption affinity and capacity, the distribution of these nanoparticles in the environment holds a potential environmental and health risk. Project objectives: The overall goal of this project was to gain a better understanding of the environmental behavior of engineered nanoparticles with DOM and organic pollutant in aqueous systems. The scope of this study includes: characterizing various types of engineered nanoparticles and their interaction with DOM; binding studies of organic contaminants by nanoparticles and DOM-nanoparticle complexes; and examining interactions in DOM-nanoparticles-contaminant systems. Major conclusions, solutions and achievements: DOM has a pronounced effect on colloidal stability of CNTs in solution and on their surface chemistry and reactivity toward associated contaminants. The structure and chemical makeup of both CNTs and DOM determine their interactions and nature of formed complexes. CNTs, contaminants and DOM can co-occur in the aquatic environment. The occurrence of co-contaminants, as well as of co-introduction of DOM, was found to suppress the adsorption of organic contaminants to CNTs through both competition over adsorption sites and direct interactions in solution. Furthermore, the release of residual contaminants from CNTs could be enhanced by biomolecules found in the digestive as well as the respiratory tracts, thus increasing the bioaccessibility of adsorbed contaminants and possibly the overall toxicity of contaminant-associated CNTs. Contaminant desorption could be promoted by both solubilization and sorptive competition by biological surfactants. Scientific and agricultural implications: The information gained in the current project may assist in predicting the transport and fate of both CNTs and associated contaminants in the natural environment. Furthermore, the results imply a serious health risk from contaminant-associated CNTs.

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