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Sample records for hydrophobic organic solutes

  1. The potential for solubilizing agents to enhance the remediation of hydrophobic organic solutes in soil-water suspensions. [Quarterly report

    Energy Technology Data Exchange (ETDEWEB)

    Laha, S.; Liu, Z.; Edwards, D.; Luthy, R.G.

    1991-02-01

    This paper discusses the feasibility for use of surfactant solubilizing agents to enhance the solubility and the rate of microbial degradation of hydrophobic organic solutes in soil-water suspensions. Hydrophobic organic contaminants are strongly sorbed to soil or sediment material, and as a consequence the rate of microbial degradation may depend greatly on the desorption of the sorbed-phase contaminant and the accessibility of the contaminant to soil microorganisms. Chemical solubilizing agents may enhance the rate of hydrophobic organic solute degradation by increasing the rate of solute desorption from soil and the extent of solute partitioning to the aqueous phase. The presentation will review on-going research on: surfactant solubilization of polycyclic aromatic hydrocarbon (PAH) compounds in clean water, and in soil-water suspensions; and experiments to assess if the addition of surfactant to soil-water suspension results in faster rate of mineralization of PAH compounds in soil.

  2. The potential for solubilizing agents to enhance the remediation of hydrophobic organic solutes in soil-water suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Laha, S.; Liu, Z.; Edwards, D.; Luthy, R.G.

    1991-02-01

    This paper discusses the feasibility for use of surfactant solubilizing agents to enhance the solubility and the rate of microbial degradation of hydrophobic organic solutes in soil-water suspensions. Hydrophobic organic contaminants are strongly sorbed to soil or sediment material, and as a consequence the rate of microbial degradation may depend greatly on the desorption of the sorbed-phase contaminant and the accessibility of the contaminant to soil microorganisms. Chemical solubilizing agents may enhance the rate of hydrophobic organic solute degradation by increasing the rate of solute desorption from soil and the extent of solute partitioning to the aqueous phase. The presentation will review on-going research on: surfactant solubilization of polycyclic aromatic hydrocarbon (PAH) compounds in clean water, and in soil-water suspensions; and experiments to assess if the addition of surfactant to soil-water suspension results in faster rate of mineralization of PAH compounds in soil.

  3. Study on the removal of organic micropollutants from aqueous and ethanol solutions by HAP membranes with tunable hydrophilicity and hydrophobicity.

    Science.gov (United States)

    He, Junyong; Li, Yulian; Cai, Xingguo; Chen, Kai; Zheng, Hejing; Wang, Chengming; Zhang, Kaisheng; Lin, Dongyue; Kong, Lingtao; Liu, Jinhuai

    2017-05-01

    A biocompatible and uniquely defined hydroxyapatite (HAP) adsorption membrane with a sandwich structure was developed for the removal of organic micropollutants for the first time. Both the adsorption and membrane technique were used for the removal of organic micropollutants. The hydrophilicity and hydrophobicity of the HAP adsorbent and membrane were tunable by controlling the surface structure of HAP. The adsorption of organic micropollutants on the HAP adsorbent was studied in batch experiments. The adsorption process was fit with the Freundlich model, while the adsorption kinetics followed the pseudo-second-order model. The HAP membrane could remove organic micropollutants effectively by dynamic adsorption in both aqueous and ethanol solutions. The removal efficiencies of organic micropollutants depended on the solution composition, membrane thickness and hydrophilicity, flow rate, and the initial concentration of organic micropollutants. The adsorption capacities of the HAP membrane with a sandwich structure (membrane thickness was 0.3 mm) were 6700, 6510, 6310, 5960, 5490, 5230, 4980 and 4360 L m(-2) for 1-naphthyl amine, 2-naphthol, bisphenol S, propranolol hydrochloride, metolachlor, ethinyl oestradiol, 2,4-dichlorophenol and bisphenol A, respectively, when the initial concentration was 3.0 mg L(-1). The biocompatible HAP adsorption membrane can be easily regenerated by methanol and was thus demonstrated to be a novel concept for the removal of organic micropollutants from both aqueous and organic solutions.

  4. Removal of hydrophobic organic pollutants from soil washing/flushing solutions: A critical review.

    Science.gov (United States)

    Trellu, Clément; Mousset, Emmanuel; Pechaud, Yoan; Huguenot, David; van Hullebusch, Eric D; Esposito, Giovanni; Oturan, Mehmet A

    2016-04-01

    The release of hydrophobic organoxenobiotics such as polycyclic aromatic hydrocarbons, petroleum hydrocarbons or polychlorobiphenyls results in long-term contamination of soils and groundwaters. This constitutes a common concern as these compounds have high potential toxicological impact. Therefore, the development of cost-effective processes with high pollutant removal efficiency is a major challenge for researchers and soil remediation companies. Soil washing (SW) and soil flushing (SF) processes enhanced by the use of extracting agents (surfactants, biosurfactants, cyclodextrins etc.) are conceivable and efficient approaches. However, this generates high strength effluents containing large amount of extracting agent. For the treatment of these SW/SF solutions, the goal is to remove target pollutants and to recover extracting agents for further SW/SF steps. Heterogeneous photocatalysis, technologies based on Fenton reaction chemistry (including homogeneous photocatalysis such as photo-Fenton), ozonation, electrochemical processes and biological treatments have been investigated. Main advantages and drawbacks as well as target pollutant removal mechanisms are reviewed and compared. Promising integrated treatments, particularly the use of a selective adsorption step of target pollutants and the combination of advanced oxidation processes with biological treatments, are also discussed.

  5. Hydrophobic Solvation: Aqueous Methane Solutions

    Science.gov (United States)

    Konrod, Oliver; Lankau, Timm

    2007-01-01

    A basic introduction to concept of a solvation shell around an apolar solute as well as its detection is presented. The hydrophobic solvation of toluene is found to be a good teaching example which connects macroscopic, phenomenological thermodynamic results with an atomistic point of view.

  6. Hydrophobic Solvation: Aqueous Methane Solutions

    Science.gov (United States)

    Konrod, Oliver; Lankau, Timm

    2007-01-01

    A basic introduction to concept of a solvation shell around an apolar solute as well as its detection is presented. The hydrophobic solvation of toluene is found to be a good teaching example which connects macroscopic, phenomenological thermodynamic results with an atomistic point of view.

  7. Solution properties of hydrophobically modified

    Directory of Open Access Journals (Sweden)

    A.M. Al-Sabagh

    2016-12-01

    Full Text Available We tested nine hydrophobically modified polyacrylamides with molecular weights situated between 1.58 and 0.89 × 106 g/mol for enhanced oil recovery applications. Their solution properties were investigated in the distilled water, brine solution, formation water and sea water. Their critical association concentrations were determined from the relationship between their concentrations and the corresponding apparent viscosities (ηapp at 30 °C at shear rate 6 s−1. They were between 0.4 and 0.5 g/dl. The brine solutions of 0.5 g/dl of HM-PAMs were investigated at different conditions regarding their apparent viscosities. Such conditions were mono and divalent cations, temperature ranging from 30 to 90 °C, the shear rate ranging from 6 to 30 s−1 and the aging time for 45 days. The surface and interfacial tensions for the HM-PAMs were measured for concentration range from 0.01 to 1 g/dl brine solutions at 30 °C and their emulsification efficiencies were investigated for 7 days. The discrepancy in the properties and efficiencies of the tested copolymers was discussed in the light of their chemical structure.

  8. Preparation of hydrophobic organic aeorgels

    Science.gov (United States)

    Baumann, Theodore F.; Satcher, Jr., Joe H.; Gash, Alexander E.

    2007-11-06

    Synthetic methods for the preparation of hydrophobic organics aerogels. One method involves the sol-gel polymerization of 1,3-dimethoxybenzene or 1,3,5-trimethoxybenzene with formaldehyde in non-aqueous solvents. Using a procedure analogous to the preparation of resorcinol-formaldehyde (RF) aerogels, this approach generates wet gels that can be dried using either supercritical solvent extraction to generate the new organic aerogels or air dried to produce an xerogel. Other methods involve the sol-gel polymerization of 1,3,5 trihydroxy benzene (phloroglucinol) or 1,3 dihydroxy benzene (resorcinol) and various aldehydes in non-aqueous solvents. These methods use a procedure analogous to the one-step base and two-step base/acid catalyzed polycondensation of phloroglucinol and formaldehyde, but the base catalyst used is triethylamine. These methods can be applied to a variety of other sol-gel precursors and solvent systems. These hydrophobic organics aerogels have numerous application potentials in the field of material absorbers and water-proof insulation.

  9. Sorption of Hydrophobic Organic Compounds on Natural Sorbents and Organoclays from Aqueous and Non-Aqueous Solutions: A Mini-Review

    Directory of Open Access Journals (Sweden)

    Francis Moyo

    2014-05-01

    Full Text Available Renewed focus on the sorption of hydrophobic organic chemicals (HOCs onto mineral surfaces and soil components is required due to the increased and wider range of organic pollutants being released into the environment. This mini-review examines the possibility of the contribution and mechanism of HOC sorption onto clay mineral sorbents such as kaolinite, and soil organic matter and the possible role of both in the prevention of environmental contamination by HOCs. Literature data indicates that certain siloxane surfaces can be hydrophobic. Therefore soils can retain HOCs even at low soil organic levels and the extent will depend on the structure of the pollutant and the type and concentration of clay minerals in the sorbent. Clay minerals are wettable by nonpolar solvents and so sorption of HOCs onto them from aqueous and non-aqueous solutions is possible. This is important for two reasons: firstly, the movement and remediation of soil environments will be a function of the concentration and type of clay minerals in the soil. Secondly, low-cost sorbents such as kaolinite and expandable clays can be added to soils or contaminated environments as temporary retention barriers for HOCs. Inorganic cations sorbed onto the kaolinite have a strong influence on the rate and extent of sorption of hydrophobic organic pollutants onto kaolinite. Structural sorbate classes that can be retained by the kaolinite matrix are limited by hydrogen bonding between hydroxyl groups of the octahedral alumosilicate sheet and the tetrahedral sheet with silicon. Soil organic carbon plays a key role in the sorption of HOCs onto soils, but the extent will be strongly affected by the structure of the organic soil matter and the presence of soot. Structural characterisation of soil organic matter in a particular soil should be conducted during a particular contamination event. Contamination by mining extractants and antibiotics will require renewed focus on the use of the QSAR

  10. Solubilization of Hydrophobic Dyes in Surfactant Solutions

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    Ali Reza Tehrani-Bagha

    2013-02-01

    Full Text Available In this paper, the use of surfactants for solubilization of hydrophobic organic dyes (mainly solvent and disperse dyes has been reviewed. The effect of parameters such as the chemical structures of the surfactant and the dye, addition of salt and of polyelectrolytes, pH, and temperature on dye solubilization has been discussed. Surfactant self-assemble into micelles in aqueous solution and below the concentration where this occurs—the critical micelle concentration (CMC—there is no solubilization. Above the CMC, the amount of solubilized dye increases linearly with the increase in surfactant concentration. It is demonstrated that different surfactants work best for different dyes. In general, nonionic surfactants have higher solubilization power than anionic and cationic surfactants. It is likely that the reason for the good performance of nonionic surfactants is that they allow dyes to be accommodated not only in the inner, hydrocarbon part of the micelle but also in the headgroup shell. It is demonstrated that the location of a dye in a surfactant micelle can be assessed from the absorption spectrum of the dye-containing micellar solution.

  11. Rheological Properties of Hydrophobically Associating Polyacrylamide Solution

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A temperature-resistant, salt-tolerant polyacrylamide, hydrophobically associating polymer (HAP), was synthesized in the State Key Laboratory of Heavy Oil Processing. The rheological behavior of HAP solution was investigated by means of flow experiments in porous media and by using a HAAKE RS600 rheometer. The results of Nuclepore membrane filtration showed that filtration time increased sharply when the critical association concentration was reached. Shear rate had a greater impact on viscosity and shear stress with increasing HAP concentration. The HAP solution with a concentration of 100 mg/L (salinity 32,868 mg/L) exhibited negative thixotropy. However, at the same salinity the HAP solution showed thixotropy and its viscosity became greater when the polymer concentration increased to 1,500 mg/L.The flow experiments in cemented core samples indicated that the resistance factor and residual resistance factor of the HAP solution were 31.8 and 12 when polymer concentration and salinity were 1,500 mg/L, 32,868 mg/L at 85℃ respectively,which is favorable for flooding application. Such factors of partially hydrolyzed polyacrylamide 3530S were merely 3.14 and 1.71, so it could not be applied to polymer flooding in the oilfield with high temperature and high salinity.

  12. Forces between Hydrophobic Solids in Concentrated Aqueous Salt Solution

    OpenAIRE

    Mastropietro, Dean J; Ducker, William A.

    2012-01-01

    Much research has focused on the discovery and description of long-ranged forces between hydrophobic solids immersed in water. Here we show that the force between high contact-angle solids in concentrated salt solution (1 M KCl) agrees very well with van der Waals forces calculated from Lifshitz theory for separations greater than 5 nm. The hydrophobic solids are octadecyltrichlorosilane-coated glass, with an advancing contact angle of 108 degrees. Thus, in 1 M salt solution, it is unnecessar...

  13. Why water reorientation slows without iceberg formation around hydrophobic solutes.

    Science.gov (United States)

    Laage, Damien; Stirnemann, Guillaume; Hynes, James T

    2009-02-26

    The dynamics of water molecules next to hydrophobic solutes is investigated, specifically addressing the recent controversy raised by the first time-resolved observations, which concluded that some water molecules are immobilized by hydrophobic groups, in strong contrast to previous NMR conclusions. Through molecular dynamics simulations and an analytic jump reorientation model, we identify the water reorientation mechanism next to a hydrophobic solute and provide evidence that no water molecules are immobilized by hydrophobic solutes. Their moderate rotational slowdown compared to bulk water (e.g., by a factor of less than 2 at low solute concentration) is mainly due to slower hydrogen-bond exchange. The slowdown is quantitatively described by a solute excluded volume effect at the transition state for the key hydrogen-bond exchange in the reorientation mechanism. We show that this picture is consistent with both ultrafast anisotropy and NMR experimental results and that the transition state excluded volume theory yields quantitative predictions of the rotational slowdown for diverse hydrophobic solutes of varying size over a wide concentration range. We also explain why hydrophobic groups slow water reorientation less than do some hydrophilic groups.

  14. Sequestration of hydrophobic organic contaminants by geosorbents

    Science.gov (United States)

    Luthy, Richard G.; Aiken, George R.; Brusseau, Mark L.; Cunningham, Scott D.; Gschwend, Philip M.; Pignatello, Joseph J.; Reinhard, Martin; Traina, Samuel J.; Weber, Walter J.; Westall, John C.

    1997-01-01

    The chemical interactions of hydrophobic organic contaminants (HOCs) with soils and sediments (geosorbents) may result in strong binding and slow subsequent release rates that significantly affect remediation rates and endpoints. The underlying physical and chemical phenomena potentially responsible for this apparent sequestration of HOCs by geosorbents are not well understood. This challenges our concepts for assessing exposure and toxicity and for setting environmental quality criteria. Currently there are no direct observational data revealing the molecular-scale locations in which nonpolar organic compounds accumulate when associated with natural soils or sediments. Hence macroscopic observations are used to make inferences about sorption mechanisms and the chemical factors affecting the sequestration of HOCs by geosorbents. Recent observations suggest that HOC interactions with geosorbents comprise different inorganic and organic surfaces and matrices, and distinctions may be drawn along these lines, particularly with regard to the roles of inorganic micropores, natural sorbent organic matter components, combustion residue particulate carbon, and spilled organic liquids. Certain manipulations of sorbates or sorbent media may help reveal sorption mechanisms, but mixed sorption phenomena complicate the interpretation of macroscopic data regarding diffusion of HOCs into and out of different matrices and the hysteretic sorption and aging effects commonly observed for geosorbents. Analytical characterizations at the microscale, and mechanistic models derived therefrom, are needed to advance scientific knowledge of HOC sequestration, release, and environmental risk.

  15. Synthesis and Aqueous Solution Viscosity of Hydrophobically Modified Xanthan Gum

    Institute of Scientific and Technical Information of China (English)

    QIAN Xiao-lin; WU Wen-hui; YU Pei-zhi; WANG Jian-quan

    2007-01-01

    Two xanthan gum derivatives hydrophobically modified by 4 or 8 tetradecyl chains per 100 xanthan gum structure units were synthesized. The derivatives were studied by scanning electron microscope and pyrene fluorescence spectrometry. And the aqueous solution apparent viscosity of the derivatives was investigated. The results indicate that the network of the derivatives with more hydrophobic groups is closer and tighter. With increasing of alkyl chain substitution degree, the hydrophobically associating interactions enhance in aqueous solution. Aqueous solution apparent viscosity of the derivatives increases with increasing of polymer concentration and alkyl substitution degree, and decreases with the increase of temperature. In the brine solution, the strong viscosity enhancement phenomenon appears. The interaction between the derivatives and surfactant sodium dodecylbenzene sulfonate is strong.

  16. Forces between hydrophobic solids in concentrated aqueous salt solution.

    Science.gov (United States)

    Mastropietro, Dean J; Ducker, William A

    2012-03-09

    Much research has focused on the discovery and description of long-ranged forces between hydrophobic solids immersed in water. Here we show that the force between high contact-angle solids in concentrated salt solution (1 M KCl) agrees very well with van der Waals forces calculated from Lifshitz theory for separations greater than 5 nm. The hydrophobic solids are octadecyltrichlorosilane-coated glass, with an advancing contact angle of 108°. Thus, in 1 M salt solution, it is unnecessary to invoke the presence of a hydrophobic force at separations greater than 5 nm. Through measurement in salt solution, we avoid the necessity of accounting for large electrostatic forces that frequently occur in pure water and may obscure resolution of other forces.

  17. Size selective hydrophobic adsorbent for organic molecules

    Science.gov (United States)

    Sharma, Pramod K. (Inventor); Hickey, Gregory S. (Inventor)

    1997-01-01

    The present invention relates to an adsorbent formed by the pyrolysis of a hydrophobic silica with a pore size greater than 5 .ANG., such as SILICALITE.TM., with a molecular sieving polymer precursor such as polyfurfuryl alcohol, polyacrylonitrile, polyvinylidene chloride, phenol-formaldehyde resin, polyvinylidene difluoride and mixtures thereof. Polyfurfuryl alcohol is the most preferred. The adsorbent produced by the pyrolysis has a silicon to carbon mole ratio of between about 10:1 and 1:3, and preferably about 2:1 to 1:2, most preferably 1:1. The pyrolysis is performed as a ramped temperature program between about 100.degree. and 800.degree. C., and preferably between about 100.degree. and 600.degree. C. The present invention also relates to a method for selectively adsorbing organic molecules having a molecular size (mean molecular diameter) of between about 3 and 6 .ANG. comprising contacting a vapor containing the small organic molecules to be adsorbed with the adsorbent composition of the present invention.

  18. Hydrophobic Volume Effects in Albumin Solutions.

    Science.gov (United States)

    Schrade, P.; Klein, H.; Egry, I.; Ademovic, Z.; Klee, D.

    2001-02-15

    Density measurements of aqueous albumin solutions as a function of concentration and temperature are reported. The solvents were H(2)O, D(2)O, and a physiological H(2)O-based buffer. An anomaly of the density at very small concentrations of albumin in D(2)O was found. Furthermore, the partial specific volume of albumin is remarkably different in D(2)O and H(2)O. We attribute both effects to structural differences of the solvents. Copyright 2001 Academic Press.

  19. Synthesis and Solution Properties of Hydrophobic Associating Polymers

    Institute of Scientific and Technical Information of China (English)

    任鲲; 姜桂元; 徐春明; 林梅钦

    2005-01-01

    Acrylamide/2-acrylamido alkane sulfonic acid hydrophobic associating copolymers were synthesized by micellar copolymerization. Effects of hydrophobe content, polymer concentration, salinity and surfactant on rheological behavior of copolymers were investigated and the conformation of polymers in solution was studied by means of environmental scanning electronic microscopy and dynamic light scattering. The experimental results showed that in the dilute regime the hydrophobic parts could interact intramolecularly, while in the regime where the polymer concentration was higher than the critical association concentration, intermolecular hydrophobic association became predominant. Within the limit of the solubility, the critical association concentration of the polymer decreased with the increase of the salinity. The experimental results of the solution conformation indicated the presence of the three-dimensional network structure in deionized water and the size of the mesh in the network varied with the polymer concentration. In NaG1 solution, above the critical association concentration, an increase in polymer concentration enhanced the intermolecular association and also enlarged the hydrodynamic radius. It would result in the imorovement of the thickening power of polvmers.

  20. Water's structure around hydrophobic solutes and the iceberg model.

    Science.gov (United States)

    Galamba, N

    2013-02-21

    The structure of water in the hydration shells of small hydrophobic solutes was investigated through molecular dynamics. The results show that a subset of water molecules in the first hydration shell of a nonpolar solute have a significantly enhanced tetrahedrality and a slightly larger number of hydrogen bonds, relative to the molecules in water at room temperature, consistent with the experimentally observed negative excess entropy and increased heat capacity of hydrophobic solutions at room temperature. This ordering results from the rearrangement of a small number of water molecules near the nonpolar solutes that occupy one to two vertices of the enhanced water tetrahedra. Although this structuring is not nearly like that often associated with a literal interpretation of the term "iceberg" in the Frank and Evans iceberg model, it does support a moderate interpretation of this model. Thus, the tetrahedral orientational order of this ensemble of water molecules is comparable to that of liquid water at ~10 °C, although not accompanied by the small contraction of the O-O distance observed in cold water. Further, we show that the structural changes of water in the vicinity of small nonpolar solutes cannot be inferred from the water radial distribution functions, explaining why this increased ordering is not observed through neutron diffraction experiments. The present results restore a molecular view where the slower translational and reorientational dynamics of water near hydrophobic groups has a structural equivalent resembling water at low temperatures.

  1. Reference interaction site model with hydrophobicity induced density inhomogeneity: An analytical theory to compute solvation properties of large hydrophobic solutes in the mixture of polyatomic solvent molecules

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Siqin [The HKUST Shenzhen Research Institute, Shenzhen (China); Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); Sheong, Fu Kit [Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); Huang, Xuhui, E-mail: xuhuihuang@ust.hk [The HKUST Shenzhen Research Institute, Shenzhen (China); Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); Division of Biomedical Engineering, Center of Systems Biology and Human Health, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

    2015-08-07

    Reference interaction site model (RISM) has recently become a popular approach in the study of thermodynamical and structural properties of the solvent around macromolecules. On the other hand, it was widely suggested that there exists water density depletion around large hydrophobic solutes (>1 nm), and this may pose a great challenge to the RISM theory. In this paper, we develop a new analytical theory, the Reference Interaction Site Model with Hydrophobicity induced density Inhomogeneity (RISM-HI), to compute solvent radial distribution function (RDF) around large hydrophobic solute in water as well as its mixture with other polyatomic organic solvents. To achieve this, we have explicitly considered the density inhomogeneity at the solute-solvent interface using the framework of the Yvon-Born-Green hierarchy, and the RISM theory is used to obtain the solute-solvent pair correlation. In order to efficiently solve the relevant equations while maintaining reasonable accuracy, we have also developed a new closure called the D2 closure. With this new theory, the solvent RDFs around a large hydrophobic particle in water and different water-acetonitrile mixtures could be computed, which agree well with the results of the molecular dynamics simulations. Furthermore, we show that our RISM-HI theory can also efficiently compute the solvation free energy of solute with a wide range of hydrophobicity in various water-acetonitrile solvent mixtures with a reasonable accuracy. We anticipate that our theory could be widely applied to compute the thermodynamic and structural properties for the solvation of hydrophobic solute.

  2. Hydrophobicity and thermodynamic response for aqueous solutions of amphiphiles

    Science.gov (United States)

    Zemánková, Katerina; Troncoso, Jacobo; Cerdeiriña, Claudio A.; Romaní, Luis; Anisimov, Mikhail A.

    2016-06-01

    The anomalous behavior of aqueous solutions of amphiphiles in the water-rich region is analyzed via a phenomenological approach that utilizes the isobaric heat capacity Cp as an experimental probe. We report extensive data for solutions of 14 amphiphiles as a function of temperature at atmospheric pressure. Beyond that, Cp data but also isobaric thermal expansivities and isothermal compressibilities for three solutions of tert-butanol as a function of both temperature and pressure are presented. Results rule out the possibility that the observed phenomenology is associated with the anomalous thermodynamics of pure water. Indeed, our Cp data, quantitatively consistent with recent spectroscopic analyses, suggest that water-mediated interactions between the nonpolar parts of amphiphiles are at the origin of anomalies, with the effects of such "hydrophobic aggregation" being observed at mole fractions as small as 0.01. Physicochemical details like the size, the electronic charge distribution and the geometry of amphiphile molecules as well as third-order derivatives of the Gibbs energy and the associated Koga lines support the above claims while they further contribute to characterizing the role of hydrophobicity in these phenomena. Progress with a view to gain a deeper, more concrete understanding remains.

  3. Solute-induced dissolution of hydrophobic ionic liquids in water.

    Science.gov (United States)

    Rickert, Paul G; Stepinski, Dominique C; Rausch, David J; Bergeron, Ruth M; Jakab, Sandrine; Dietz, Mark L

    2007-04-15

    Significant solubilization of ostensibly water-immiscible ionic liquids (ILs) in acidic aqueous phases is induced by the presence of any of a variety of neutral extractants, the apparent result of the formation of the protonated form of the extractant and its subsequent exchange for the cationic component of the IL. The extent of this solubilization is shown to diminish with increasing hydrophobicity of the IL cation and decreasing extractant basicity. These observations raise concerns as to the viability of ILs as "drop in replacements" for traditional organic solvents in the solvent extraction of metal ions.

  4. PROPERTIES OF DILUTE SOLUTIONS OF HYDROPHOBICALLY MODIFIED POLY(4-VINYL PYRIDINE) (POLYSOAPS)

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Hydrophobically modified poly(4-vinyl pyridines) by alkyl bromides are kinds of polysoap similar to the surfactant. Properties of dilute solutions were studied through the viscosity measurements in pure water and NaCl solutions. In aqueous solutions of polysoaps hydrophobic interaction can be attributed to aggregation of hydrophobic groups of the polysoap main chains. The hydrophobic groups of polysoap can aggregate to form hydrophobic microdomains (micelles) in aqueous solution. This is a compact conformation. The formation of such microdomains is a process of dynamic equilibrium.

  5. Hydrophobic Porous Material Adsorbs Small Organic Molecules

    Science.gov (United States)

    Sharma, Pramod K.; Hickey, Gregory S.

    1994-01-01

    Composite molecular-sieve material has pore structure designed specifically for preferential adsorption of organic molecules for sizes ranging from 3 to 6 angstrom. Design based on principle that contaminant molecules become strongly bound to surface of adsorbent when size of contaminant molecules is nearly same as that of pores in adsorbent. Material used to remove small organic contaminant molecules from vacuum systems or from enclosed gaseous environments like closed-loop life-support systems.

  6. Modeling uptake of hydrophobic organic contaminants into polyethylene passive samplers.

    Science.gov (United States)

    Thompson, Jay M; Hsieh, Ching-Hong; Luthy, Richard G

    2015-02-17

    Single-phase passive samplers are gaining acceptance as a method to measure hydrophobic organic contaminant (HOC) concentration in water. Although the relationship between the HOC concentration in water and passive sampler is linear at equilibrium, mass transfer models are needed for nonequilibrium conditions. We report measurements of organochlorine pesticide diffusion and partition coefficients with respect to polyethylene (PE), and present a Fickian approach to modeling HOC uptake by PE in aqueous systems. The model is an analytic solution to Fick's second law applied through an aqueous diffusive boundary layer and a polyethylene layer. Comparisons of the model with existing methods indicate agreement at appropriate boundary conditions. Laboratory release experiments on the organochlorine pesticides DDT, DDE, DDD, and chlordane in well-mixed slurries support the model's applicability to aqueous systems. In general, the advantage of the model is its application in the cases of well-agitated systems, low values of polyethylene-water partioning coefficients, thick polyethylene relative to the boundary layer thickness, and/or short exposure times. Another significant advantage is the ability to estimate, or at least bound, the needed exposure time to reach a desired CPE without empirical model inputs. A further finding of this work is that polyethylene diffusivity does not vary by transport direction through the sampler thickness.

  7. Structure of aqueous electrolyte solutions near a hydrophobic surface

    Directory of Open Access Journals (Sweden)

    M.Kinoshita

    2007-09-01

    Full Text Available The structure of aqueous solutions of 1:1 salts (KCl, NaCl, KF,and CsI near a hydrophobic surface is analysed using the angle-dependent integral equation theory. Water molecules are taken to be hard spheres imbedded with multipolar moments including terms up to octupole order, and hard spherical ions are immersed in this model water. The many-body interactions associated with molecular polarizability are treated at the self-consistent mean field level. The effects of cationic and anionic sizes and salt concentration in the bulk are discussed in detail. As the salt concentration increases, the layer of water molecules next to the surface becomes denser but its orientational order remains almost unchanged. The concentration of each ion at the surface can be drastically different from that in the bulk. Asa striking example, at sufficiently low salt concentrations, the concentration of I- is about 500 times higher than that of F- at the surface.

  8. Peptide environment specifies conformation. Helicity of hydrophobic segments compared in aqueous, organic, and membrane environments.

    Science.gov (United States)

    Li, S C; Deber, C M

    1993-11-05

    Transmembrane segments in integral membrane proteins exist characteristically as helices in lipid bilayers, yet are often rich in residues considered helix-destabilizing (Val, Ile, Gly) in soluble proteins. We propose that helicity of a transmembrane segment is likely to be affected by factors other than the "intrinsic" helical propensities of its component amino acids. This hypothesis is tested by comparing the conformation(s) in aqueous, organic, membrane-mimetic (micellar), and membrane (bilayer) environments of designed model peptides with systematically altered helical propensity and/or segmental hydrophobicity. Peptides of prototypic sequence NH2-(Ser-Lys)2-Ala5-Leu6-Ala7-Ala8-Leu9-Ala10-++ +Trp11-Ala12-Leu13-Ala14- (Lys-Ser)3-OH were synthesized, which incorporate a hydrophobic core "guest" segment (residues 5-14) into a water-soluble hydrophilic host matrix. Related peptides featured substitution of Leu6,9,13-->Gly, Leu6,9,13-->Ala, and Ala7,10,14-->Gly. Circular dichroism spectra revealed that algorithms for soluble proteins correctly predicted peptide helical proclivities in aqueous solutions, but peptide helicity in organic (trifluoroethanol) solvents, membrane-mimetic SDS micelles, and negatively charged lipid bilayer vesicles, was found to be governed almost exclusively by the segmental hydrophobicity of the peptide mid-hydrophobic core segment. In related Trp fluorescence studies, peptide-membrane association was similarly correlated with extent of hydrophobic interaction.

  9. Biomimetic solution against dewetting in a highly hydrophobic nanopore.

    Science.gov (United States)

    Picaud, Fabien; Paris, Guillaume; Gharbi, Tijani; Balme, Sébastien; Lepoitevin, Mathilde; Tangaraj, Vidhyadevi; Bechelany, Mikhael; Janot, Jean Marc; Balanzat, Emmanuel; Henn, François

    2016-06-14

    A water molecule is the foundation of life and is the primary compound in every living system. While many of its properties are understood in a bulk solvent, its behavior in a small hydrophobic nanopore still raises fundamental questions. For instance, a wetting/dewetting transition in a hydrophobic solid-state or a polymer nanopore occurs stochastically and can only be prevented by external physical stimuli. Controlling these transitions would be a primary requirement to improve many applications. Some biological channels, such as gramicidin A (gA) proteins, show a high rate of water and ion diffusion in their central subnanochannel while their external surface is highly hydrophobic. The diameter of this channel is significantly smaller than the inner size of the lowest artificial nanopore in which water drying occurs (i.e. 1.4 nm). In this paper, we propose an innovative idea to generate nanopore wetting as a result of which the application of an external field is no longer required. In a nanopore, the drying or wetting of the inner walls occurs randomly (in experiments and in simulations). However, we have shown how the confinement of gA, in a dried hydrophobic nanopore, rapidly generates a stable wetting of the latter. We believe that this simple idea, based on biomimetism, could represent a real breakthrough that could help to improve and develop new nanoscale applications.

  10. Hydrophobic and moisture-stable metal–organic frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Carlos A.; Nune, Satish K.; Annapureddy, Harsha V.; Dang, Liem X.; McGrail, B. Peter; Zheng, Feng; Polikarpov, Evgueni; King, David L.; Freeman, Charles J.; Brooks, Kriston P.

    2015-08-15

    Metal-organic frameworks (MOFs) have proved to be very attractive for applications including gas storage, separation, sensing and catalysis. In particular, CO2 separation from flue gas in post-combustion processes is one of the main focuses of research among the scientific community. One of the major issues that are preventing the successful commercialization of these novel materials (e.g., MgDOBDC and NiDOBDC) is their high affinity towards water that not only compromises gas sorption capacity but also the chemical stability. In this paper, we demonstrate a novel post-synthesis modification approach to modify MOFs towards increasing hydrophobic behavior and chemical stability against moisture without compromising CO2 sorption capacity. Our approach consists of incorporating hydrophobic moieties on the external surface of the MOFs via physical adsorption. The rationale behind this concept is to increase the surface hydrophobicity in the porous materials without the need of introducing bulky functionalities inside the pore which compromises the sorption capacity toward other gases. This allows MOF interaction/sorption of CO2 molecules comparable to unmodified MOFs. We herein report preliminary results on three routinely studied MOF materials [MIL-101(Cr), MgDOBDC and NiDOBDC] demonstrating that the polymer-modified MOFs retain CO2 sorption capacity while reducing the water adsorption up to three times, respect to the un-modified materials, via an equilibrium effect. Furthermore, the water stability of the polymer-functionalized MOFs is significantly higher than the water stability of the bare material. Molecular dynamic simulations demonstrated that this equilibrium effect implies a fundamental and permanent change in the water sorption capacity of MOFs. This approach can also be employed to render moisture stability and selectivity to MOFs that find applications in gas separations, catalysis and sensing where water plays a critical role in compromising MOF

  11. A computational solution to analyze hydrophobic characteristics in protein chains

    Science.gov (United States)

    Soares, Marilia Amável Gomes; Azevedo, Alexandre; Missailidis, Sotiris; Silva, Dilson

    2016-12-01

    This paper presents a program developed to facilitate calculations of the total or partial hidrophobicity value of polypeptides and proteins chains. It was built using the Fortran 77 language and performs additional functions, determining the total free energy and the electromotive force of an amino acid in a protein. These values were then used to estimate the average hydrophobicity of the protein or fragment sequence.

  12. Interaction of engineered nanomaterials with hydrophobic organic pollutants

    Science.gov (United States)

    Sahle-Demessie, E.; Han, Changseok; Zhao, Amy; Hahn, Bill; Grecsek, Heidi

    2016-07-01

    As nanomaterials become an increasing part of everyday consumer products, it is imperative to monitor their potential release during production, use and disposal, and to assess their impact on the health of humans and the ecosystem. This necessitates research to better understand how the properties of engineered nanomaterials (ENMs) lead to their accumulation and redistribution in the environment, and to assess whether they could become novel pollutants or if they can affect the mobility and bioavailability of other toxins. This study focuses on understanding the influence of nanostructured-TiO2 and the interaction of multi-walled carbon nanotubes with organic pollutants in water. We studied the adsorption and water phase dispersion of model pollutants with relatively small water solubility (i.e., two- and three-ring polyaromatic hydrocarbons and insecticides) with respect to ENMs. The sorption of pollutants was measured based on water phase analysis, and by separating suspended particles from the water phase and analyzing dried samples using integrated thermal-chromatographic-mass spectroscopic (TGA/GC/MS) techniques. Solid phase analysis using a combination of TGA/GC/MS is a novel technique that can provide real-time quantitative analysis and which helps to understand the interaction of hydrophobic organic pollutants and ENMs. The adsorption of these contaminants to nanomaterials increased the concentration of the contaminants in the aqueous phase as compared to the ‘real’ partitioning due to the octanol-water partitioning. The study showed that ENMs can significantly influence the adsorption and dispersion of hydrophobic/low water soluble contaminants. The type of ENM, the exposure to light, and the water pH have a significant influence on the partitioning of pollutants.

  13. Thermal destruction of organic waste hydrophobicity for agricultural soils application.

    Science.gov (United States)

    Comino, Francisco; Aranda, Víctor; Domínguez-Vidal, Ana; Ayora-Cañada, María José

    2017-11-01

    Use of organic amendments is a good strategy for combating the growing problem of soil degradation due to deterioration of organic matter content, particularly severe in semi-arid European Mediterranean regions, while at the same time providing an opportunity for recycling organic wastes. Olive mill pomace (OMP), the main by-product of the olive oil industry, is being used increasingly in olive grove soils for this purpose. Although the positive effects of OMP amendments have been widely studied, they also have some negative effects on soil. One of the most critical is that they increase water repellency (WR) due to the presence of poorly evolved, strongly aliphatic compounds. This detrimental effect has received very little attention, although it may impair plant water availability and infiltration rates, increase erosion and lower long-term soil quality. This study proposed, for the first time, thermal treatment as an effective way of reducing WR in organic amendments (i.e. mixtures of OMP, olive tree pruning, chicken manure and spent coffee grounds) prior to their application to soil. Thermal treatment at 275 °C proved effective in removing WR, while lower temperatures (175 or 225 °C) can even increase it. Changes by thermal treatment in the characteristics of the organic amendments studied with FTIR and UV-Vis spectroscopy and thermogravimetric analysis showed that it strongly reduced the aliphatic compounds mainly responsible for their hydrophobicity, concentrated aromatic compounds and increased thermostability. Heating also reduced phytotoxicity, making all of the organic amendments usable in the field (germination index over 100%). Therefore, heating at 275 °C could be an acceptable option for removing WR from organic amendments, enhancing their quality with more stable evolved characteristics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Fabrication of Super Hydrophobic Surfaces on Copper by Solution-immersion

    Institute of Scientific and Technical Information of China (English)

    龚志金; 王建莉; 吴丽梅; 王小雨; 吕国诚; 廖立兵

    2013-01-01

    Super hydrophobic copper wafer was prepared by means of solution immersion and surface self-assembly methods. Different immersion conditions were explored for the best hydrophobic surface. Scanning electron mi-croscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and water contact angle meas-urements were used to investigate the morphologies, microstructures, chemical compositions and hydrophobicity of the produced films on copper substrates, respectively. Results show that the super hydrophobic surface is composed of micro structure of Cu7S4. The films present a high water contact angle larger than 150°, a low sliding angle less than 3°, good abrasion resistance and storage stability. The molecular dynamics simulation confirms that N-dodecyl mercaptan molecules link up with Cu7S4 admirably, compared with Cu, which contributes to the stable super hy-drophobic surface.

  15. Comparison of the removal of hydrophobic trace organic contaminants by forward osmosis and reverse osmosis.

    Science.gov (United States)

    Xie, Ming; Nghiem, Long D; Price, William E; Elimelech, Menachem

    2012-05-15

    We compared the rejection behaviours of three hydrophobic trace organic contaminants, bisphenol A, triclosan and diclofenac, in forward osmosis (FO) and reverse osmosis (RO). Using erythritol, xylose and glucose as inert reference organic solutes and the membrane pore transport model, the mean effective pore size of a commercial cellulose-based FO membrane was estimated to be 0.74 nm. When NaCl was used as the draw solute, at the same water permeate flux of 5.4 L/m(2) h (or 1.5 μm/s), the adsorption of all three compounds to the membrane in the FO mode was consistently lower than that in the RO mode. Rejection of bisphenol A and diclofenac were higher in the FO mode compared to that in the RO mode. Because the molecular width of triclosan was larger than the estimated mean effective membrane pore size, triclosan was completely rejected by the membrane and negligent difference between the FO and RO modes could be observed. The difference in the separation behaviour of these hydrophobic trace organics in the FO (using NaCl the draw solute) and RO modes could be explained by the phenomenon of retarded forward diffusion of solutes. The reverse salt flux of NaCl hinders the pore diffusion and subsequent adsorption of the trace organic compounds within the membrane. The retarded forward diffusion effect was not observed when MgSO(4) and glucose were used as the draw solutes. The reverse flux of both MgSO(4) and glucose was negligible and thus both adsorption and rejection of BPA in the FO mode were identical to those in the RO mode. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  16. Interaction forces for symmetric hydrophilic and hydrophobic systems in aqueous isopropanol solutions.

    Science.gov (United States)

    Hupka, Lukasz; Nalaskowski, Jakub; Miller, Jan D

    2010-02-16

    Interaction force measurements were performed for a silica-silica hydrophilic system and for a silanated silica-silanated silica hydrophobic system using the atomic force microscopy colloidal probe technique. The influence of the solution composition on interaction forces was investigated. The hydrophilic silica-silica interactions were found to be described as a typical Derjaguin-Landau-Verwey-Overbeek (DLVO) system in solutions of various compositions, whereas silanated silica-silanated silica interactions were dominated by a long-range hydrophobic force. An increase in the isopropyl alcohol content of the solution diminishes both the repulsive forces in the case of the hydrophilic system and the attractive interactions in the case of the hydrophobic system.

  17. Hydrophobic polycationic coatings disinfect poliovirus and rotavirus solutions.

    Science.gov (United States)

    Larson, Alyssa M; Hsu, Bryan B; Rautaray, Debabrata; Haldar, Jayanta; Chen, Jianzhu; Klibanov, Alexander M

    2011-03-01

    Coating surfaces with N-alkylated polyethylenimines (PEIs), namely branched N,N-hexyl,methyl-PEI via covalent attachment to glass or linear N,N-dodecyl,methyl-PEI by physical deposition ("painting") onto polyethylene, enables the resultant materials to quickly and efficiently disinfect aqueous solutions of (non-enveloped) poliovirus and rotavirus.

  18. Description of adsorption of hydrophobic organic compounds on sediment using multi-component adsorption model

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A chemical sequential separation procedure for sediment bas been developed for the adsorptive investigation of hydrophobic organic compounds(HOCs) including four fractions: carbonate, hydrous metallic oxide(ferric oxide, manganese oxide and alumina), clay and organic matter. Adsorption isotherms of these hydrophobic solute probes, such as hexachloroethane, lindane and 1,2,4,5-tetrachlorobenzene were measured for model sorbents, model and natural sediment, and the latter of which was pretreated with the simplified sequential separation method. The linear and Langmuir models are applied to correlate the experimental data of humic substance and other model sorbents respectively. Multi-component Adsorptive Model (MCAM) was used to simulate adsorption isotherms of model and natural sediment. The results reveal that( 1 ) the separation efficiencies of carbonate, organic matter, ferric oxide, manganese oxide and alumina are 98. 1 % , 72.5% ,82.6%, 93.5% and 83.3%, respectively; (2) except for removing metallic oxide, the external structure of sediment is not changed greatly after separation; (3) the MCAM correlates the data of adsorption isotherm rather well with the maximal relative deviations of 9.76 % , 6.78 %and 9.53% for hexachloroethane, lindane and 1,2,4,5-tetrachlorobenaze in model sediment, respectively. The MCAM can clearly give expression to the different adsorptive mechanisms for HOCs in organic and inorganic matter, though the experimental data in each component are not very accurate due to the sequential separation efficiency.

  19. Effect of trimethylamine-N-oxide on pressure-induced dissolution of hydrophobic solute.

    Science.gov (United States)

    Sarma, Rahul; Paul, Sandip

    2012-09-21

    Molecular dynamics simulations are performed to study the effects of increasing trimethylamine-N-oxide (TMAO) concentration on the pressure-induced dissolution of hydrophobic solutes immersed in water. Such systems are of interest mainly because pressure increases the dissolution of hydrophobic protein interior causing protein denaturation and TMAO acts to offset the protein denaturing effect of high hydrostatic pressures. In view of this, in this study, methane molecules are considered as model hydrophobic molecules and simulations are performed for four independent TMAO solutions each at four different pressures ranging from 2 to 8 kbar. From potentials of mean force calculations, it is found that application of pressure reduces the free energy difference between contact minimum (CM) and solvent-separated (SSM) minimum of hydrophobic solute, suggesting dissolution at high pressures. TMAO, on the other hand, increases the relative stability of CM state of methane molecules relative to its SSM state. High packing efficiency of water molecules around the hydrophobic solute at high pressure is observed. Also observed are TMAO-induced enhancement of water structure and direct hydrogen-bonding interaction between TMAO and water and the correlated dehydration of hydrophobic solute. From hydrogen bond properties and dynamics calculations, it is observed that pressure increases average number of water-water hydrogen bonds while reduces their life-times. In contrast, TMAO reduces water-water hydrogen bonding but enhances their life-times. These results suggest that TMAO can reduce water penetration into the protein interior by enhancing water structure and also forming hydrogen bonds with water and hence counteracts protein unfolding.

  20. Molecular theory for the effects of solute attractive forces on hydrophobic interactions

    CERN Document Server

    Chaudhari, M I; Asthagiri, D; Tan, L; Pratt, L R

    2015-01-01

    We consider the local molecular field (LMF) theory for the effects of solute attractive forces on hydrophobic interactions. The principal result of LMF theory is outlined, then tested by obtaining radial distribution functions (rdfs) for Ar atoms in water, with and without attractive interactions distinguished by the Weeks-Chandler-Andersen (WCA) separation. Change from purely repulsive atomic solute interactions to include realistic attractive interactions substantially \\emph{diminishes} the strength of hydrophobic bonds. Since attractions make a big contribution to hydrophobic interactions, Pratt-Chandler theory, which did not include attractions, should not be simply comparable to computer simulation results with general physical interactions, including attractions. The rdfs permit evaluation of osmotic second virial coefficients $B_2$. Those $B_2$ are consistent with the conclusion that incorporation of attractive interactions leads to more positive (repulsive) values. In all cases here, $B_2$ becomes mor...

  1. Molecular-scale hydrophobic interactions between hard-sphere reference solutes are attractive and endothermic

    Science.gov (United States)

    Chaudhari, Mangesh I.; Holleran, Sinead A.; Ashbaugh, Henry S.; Pratt, Lawrence R.

    2013-01-01

    The osmotic second virial coefficients, B2, for atomic-sized hard spheres in water are attractive (B2 statistical mechanical theory. These results constitute an initial step toward detailed molecular theory of additional intermolecular interaction features, specifically, attractive interactions associated with hydrophobic solutes. PMID:24297918

  2. Permeable sorptive walls for treatment of hydrophobic organic contaminant plumes in groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Grathwohl, P.; Peschik, G. [Univ. of Tuebingen (Germany)

    1997-12-31

    Highly hydrophobic contaminants are easily adsorbed from aqueous solutions. Since for many of these compounds sorption increases with increasing organic carbon content natural materials such as bituminous shales and coals may be used in permeable sorptive walls. This, however, only applies if sorption is at equilibrium, which may not always be the case in groundwater treatment using a funnel-and-gate system. In contrast to the natural solids, granular activated carbons (GACs) have very high sorption capacities and reasonably fast sorption kinetics. The laboratory results show that application of GACs (e.g. F100) is economically feasible for in situ removal of polycyclic aromatic hydrocarbons (PAH) from groundwater at a former manufactured gas plant site (MGP). For less sorbing compounds (such as benzene, toluene, xylenes) a combination of adsorption and biodegradation is necessary (i.e. sorptive + reactive treatment).

  3. Hydrophobic core/hydrophilic shell structured mesoporous silica nanospheres: enhanced adsorption of organic compounds from water.

    Science.gov (United States)

    Li, Shuru; Jiao, Xuan; Yang, Hengquan

    2013-01-29

    Inspired by the structure features of micelle, we attempt to synthesize a novel functionalized mesoporous silica nanosphere consisting of a hydrophobic core and a hydrophilic shell. The obtained solid materials were structurally confirmed by N(2) sorption, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Their compositions were characterized by Fourier transfer infrared spectroscopy (FT-IR), solid state NMR, X-ray photoelectron spectroscopy (XPS), and elemental analysis. Its fundamental properties such as dispersibility in water or organic phase, wettability, and adsorption ability toward hydrophobic organics in water were investigated. It was revealed that these important properties could be facilely adjusted through varying structure and composition. In particular, these materials showed much better adsorption ability toward hydrophobic organic molecules in water than conventional monofunctionalized mesoporous materials, owing to possessing the hydrophobic/hydrophilic domain-segregated and hierarchically functionalized mesoporous structures. The intriguing properties would make mesoporous materials more accessible to many important applications, especially in aqueous systems.

  4. Hydrophobically modified polyelectrolytes I. Dilute solution properties of fluorocarbon-containingpoly(acrylic acid)

    Institute of Scientific and Technical Information of China (English)

    ZHOU, Hui(周晖); SONG, Guo-Qiang(宋国强); ZHANG, Yun-Xiang(章云祥); DIEING, Reinhold; MA, Lian; HAEUSSLING, Lukas

    2000-01-01

    Dilute solution viscosity of fluorocarbon-containing hydrophobically modified poly(acrylic acid) was measured in aqueous solutions of various NaCl concentrations. The intrinsic viscosity ([η]) and Huggins coefficient (kH) were evaluated using Huggins equations. It is found that, at low NaCl concentration, the modified polymers exhibit values of intrinsic viscosity ( [η] ) and Huggins coefficient (kH) similar to those of unmodified polymers. For both of the modified and unmodified polymers, the intrinsic viscosity decreases with increase of NaCl concentration, while the Huggins coefficient increases upon addition of NaCl. But the variation of [η] and kH is more significant for the modified polymers, which reflects the enhanced intra- and intermolecular hydrophobic association at higher NaCl concentration.

  5. The hydrophilic/hydrophobic ratio vs. dissolved organics removal by coagulation – A review

    Directory of Open Access Journals (Sweden)

    Djamel Ghernaout

    2014-07-01

    Full Text Available This review discusses the hydrophilic/hydrophobic ratio as a function of the hydrophilic and hydrophobic contents removal by coagulation process. It is well established that coagulation process could bring a reduction in dissolved organic carbon of around 30–60% by increasing the coagulant dose and optimising reaction pH, in which large organic molecules with hydrophobic property was removed preferentially. Furthermore, the literature affirmed that the greater removal of UV-absorbing substances indicates that alum coagulation preferentially removed the hydrophobic fraction of the total organic carbon. For the hydrophobic fraction, it needs to be removed entirely without its transformation into hydrophilic fractions by coagulation process avoiding pre-chlorination/pre-oxidation due to the risk of organic molecules fragmentation. Determining the exact numerical values of the hydrophilic/hydrophobic ratio for raw water and treated water at different stages of the treatment processes in a water treatment plant, as for the DCO/DBO5 ratio in the case of wastewater treatment, would help on more focusing on OM control and removal.

  6. Considering Hydrophobicity via Contact Angle Stability of Organic Thiols Measured with a Homemade Goniometer

    Science.gov (United States)

    Seraly, Mark; Ollander, Brooke; Statman, Ariel; Poynor, Adele

    2014-03-01

    When water meets an extended hydrophobic surface, an ultra-thin, low-density depletion layer is expected at the interface. Exactly how the depletion layer changes with change in hydrophobicity is still an open question. An accurate measure of contact angle is essential in determining how water meets a hydrophobic surface. Utilizing a homemade goniometer with ImageJ software we investigate the stability of self-assembled organic thiol monolayers, 1-octadecanethiol (ODT) and 11-mercaptoundecanoic acid (MUA). We report the changes in contact angle due to exposure to air, water, and ethanol. Other factors that affect contact angles were also considered in our investigation.

  7. Measuring binding and speciation of hydrophobic organic chemicals at controlled freely dissolved concentrations and without phase separation

    DEFF Research Database (Denmark)

    Gouliarmou, Varvara; Smith, K E C; de Jonge, Lis Wollesen

    2012-01-01

    The binding and speciation of hydrophobic organic chemicals (HOCs) in aqueous solutions were determined by controlling chemical activity and measuring total concentrations. Passive dosing was applied to control chemical activities of HOCs in aqueous solutions by equilibrium partitioning from a po...... by the low relative standard errors for the partition ratios of 0.5–8%, equivalent to 0.002–0.03 log unit. This passive dosing approach allows binding and speciation of HOCs to be studied without any phase separation steps or mass balance assumptions.......The binding and speciation of hydrophobic organic chemicals (HOCs) in aqueous solutions were determined by controlling chemical activity and measuring total concentrations. Passive dosing was applied to control chemical activities of HOCs in aqueous solutions by equilibrium partitioning from a poly......(dimethylsiloxane) polymer preloaded with the chemicals. The HOC concentrations in the equilibrated solutions [Csolution(eq)] and water [Cwater(eq)] were then measured. Free fractions of the HOCs were determined as Cwater(eq)/Csolution(eq), whereas enhanced capacities (E) of the solutions for HOCs were determined...

  8. FLUORESCENCE SPECTROSCOPIC STUDY OF THE FORMATION OF HYDROPHOBIC MICRODOMAINS IN AQUEOUS-SOLUTIONS OF POLY(ALKYLMETHYLDIALLYLAMMONIUM BROMIDES)

    NARCIS (Netherlands)

    YANG, YJ; Engberts, Jan B F N

    The conformational state of poly(alkylmethyldiallylammonium bromides) was studied in aqueous solutions using pyrene as a fluorescence probe. The results are indicative for the formation of hydrophobic microdomains in the case of several copolymers which possess sufficiently hydrophobic alkyl side

  9. FLUORESCENCE SPECTROSCOPIC STUDY OF THE FORMATION OF HYDROPHOBIC MICRODOMAINS IN AQUEOUS-SOLUTIONS OF POLY(ALKYLMETHYLDIALLYLAMMONIUM BROMIDES)

    NARCIS (Netherlands)

    YANG, YJ; ENGBERTS, JBFN

    1991-01-01

    The conformational state of poly(alkylmethyldiallylammonium bromides) was studied in aqueous solutions using pyrene as a fluorescence probe. The results are indicative for the formation of hydrophobic microdomains in the case of several copolymers which possess sufficiently hydrophobic alkyl side ch

  10. Hydrophobic monolayered nanoflakes of tungsten oxide: coupled exfoliation and fracture in a nonpolar organic medium.

    Science.gov (United States)

    Honda, Masashi; Oaki, Yuya; Imai, Hiroaki

    2015-06-21

    Coupled exfoliation and fracture induced formation of hydrophobic monolayered nanoflakes in a nonpolar organic medium. The hydrophobic monolayered nanoflakes 5-20 nm in lateral size consisted of a tungstate layer with surface modification by stearylammonium ions (C18H37NH3)0.397 H0.603Cs3W11O35·xH2O (x < 0.625).

  11. Comparative study of laterite and bentonite based organoclays: implications of hydrophobic compounds remediation from aqueous solutions.

    Science.gov (United States)

    Nafees, Muhammad; Waseem, Amir; Khan, Abdur Rehman

    2013-01-01

    Four cost effective organoclays were synthesized, characterized, and studied for the sorption of hydrophobic compounds (edible oil/grease and hydrocarbon oil) from aqueous solutions. Organoclays were prepared by cation exchange reaction of lattice ions (present onto the surface of laterite and bentonite clay minerals) with two surfactants, hexadecyl trimethyl ammonium chloride (HDTMA-Cl) and tetradecyl trimethyl ammonium bromide (TDTMA-Br). Fourier transform infrared spectroscopy and scanning electron microscopy were used for the characterization of synthesized organoclays. It was found that the amount of surfactant loading and the nature of the surfactant molecules used in the syntheses of organoclay strongly affect the sorption capacity of the clay mineral. Further, it was found that both the laterite and bentonite based organoclays efficiently removed the edible and hydrocarbon oil content from lab prepared emulsions; however, the adsorption capacity of clay mineral was greatly influenced by the nature of hydrophobic compounds as well.

  12. Dependence of the osmotic coefficients and average ionic activity coefficients on hydrophobic hydration in solutions

    Science.gov (United States)

    Sergievskii, V. V.; Rudakov, A. M.

    2016-08-01

    The model that considers the nonideality of aqueous solutions of electrolytes with allowance for independent contributions of hydration of ions of various types and electrostatic interactions was substantiated using the cluster ion model. The empirical parameters in the model equations were found to be the hydrophilic and hydrophobic hydration numbers of ions in the standard state and the dispersion of their distribution over the stoichiometric coefficients. A mathematically adequate description of the concentration dependences of the osmotic coefficients and average ion activity coefficients of electrolytes was given for several systems. The difference in the rate of the decrease in the hydrophilic and hydrophobic hydration numbers of ions leads to extremum concentration dependences of the osmotic coefficients, which were determined by other authors from isopiestic data for many electrolytes and did not find explanation.

  13. Comparative Study of Laterite and Bentonite Based Organoclays: Implications of Hydrophobic Compounds Remediation from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Muhammad Nafees

    2013-01-01

    Full Text Available Four cost effective organoclays were synthesized, characterized, and studied for the sorption of hydrophobic compounds (edible oil/grease and hydrocarbon oil from aqueous solutions. Organoclays were prepared by cation exchange reaction of lattice ions (present onto the surface of laterite and bentonite clay minerals with two surfactants, hexadecyl trimethyl ammonium chloride (HDTMA-Cl and tetradecyl trimethyl ammonium bromide (TDTMA-Br. Fourier transform infrared spectroscopy and scanning electron microscopy were used for the characterization of synthesized organoclays. It was found that the amount of surfactant loading and the nature of the surfactant molecules used in the syntheses of organoclay strongly affect the sorption capacity of the clay mineral. Further, it was found that both the laterite and bentonite based organoclays efficiently removed the edible and hydrocarbon oil content from lab prepared emulsions; however, the adsorption capacity of clay mineral was greatly influenced by the nature of hydrophobic compounds as well.

  14. Shape Controlled Hierarchical Porous Hydrophobic/Oleophilic Metal-Organic Nanofibrous Gel Composites for Oil Adsorption.

    Science.gov (United States)

    Jayaramulu, Kolleboyina; Geyer, Florian; Petr, Martin; Zboril, Radek; Vollmer, Doris; Fischer, Roland A

    2017-03-01

    A versatile and facile synthetic route toward a ultralight hierarchical poroushybrid composed of metal-organic gels and fluorinated graphene oxide is reported. The composite gels show excellent absorbency of oil and various organic solvents due to their prominent meso/macropores, notable hydrophobicity, and superoleophilicity. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Dissolved organic carbon enhances the mass transfer of hydrophobic organic compounds from Nonaqueous Phase Liquids (NAPLs) into the aqueous phase

    NARCIS (Netherlands)

    Smith, K.E.C.; Thullner, M.; Wick, L.Y.; Harms, H.

    2011-01-01

    The hypothesis that dissolved organic carbon (DOC) enhances the mass transfer of hydrophobic organic compounds from nonaqueous phase liquids (NAPLs) into the aqueous phase above that attributable to dissolved molecular diffusion alone was tested. In controlled experiments, mass transfer rates of

  16. Influence of nitrogen status on the bioconcentration of hydrophobic organic compounds to Selenastrum capricornutum

    DEFF Research Database (Denmark)

    Halling-Sørensen, B.; Nyholm, Niels; Kusk, Kresten Ole

    2000-01-01

    Changes in algal nitrogen status that increase algal lipid content also a€ect the bioconcentration of hydrophobic organic compounds (HOCs). Bioconcentration factors (BCFs) for several HOCs increased up to nine times as the total algal lipid content of the green algae Selenastrum carpricornutum in...

  17. Conformational dynamics of a hydrophobic prion fragment (113-127) in different pH and osmolyte solutions.

    Science.gov (United States)

    Inayathullah, Mohammed; Rajadas, Jayakumar

    2016-06-01

    Prion diseases are characterized by a conformational change in prion protein from its native state into beta-sheet rich aggregates that are neurotoxic. The central domain that contain a highly conserved hydrophobic region of the protein play an important role in the toxicity. The conformation of the proteins is largely influenced by various solvent environments. Here we report results of study of hydrophobic prion fragment peptide PrP(113-127) under different pH and osmolytes solution conditions. The secondary structure and the folding of PrP(113-127) was determined using circular dichroism and fluorescence spectroscopic methods. The results indicate that PrP(113-127) adopts a random coil conformation in aqueous buffer at neutral pH and that converted into beta sheet on aging. Even though the initial random coil conformation was similar in different pH conditions, the acidic as well as basic pH conditions delays the conformational transition to beta sheet. FRET results indicate that the distance between N and C-terminal regions increased on aging due to unfolding by self-assembly of the peptide into an organized beta sheet structure. Presence of osmolytes, prevented or decelerated the aggregation process of PrP(113-127) peptide. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Partitioning of hydrophobic organic contaminants between polymer and lipids for two silicones and low density polyethylene.

    Science.gov (United States)

    Smedes, Foppe; Rusina, Tatsiana P; Beeltje, Henry; Mayer, Philipp

    2017-08-11

    Polymers are increasingly used for passive sampling of neutral hydrophobic organic substances (HOC) in environmental media including water, air, soil, sediment and even biological tissue. The equilibrium concentration of HOC in the polymer can be measured and then converted into equilibrium concentrations in other (defined) media, which however requires appropriate polymer to media partition coefficients. We determined thus polymer-lipid partition coefficients (KPL) of various PCB, PAH and organochlorine pesticides by equilibration of two silicones and low density polyethylene (LDPE) with fish oil and Triolein at 4 °C and 20 °C. We observed (i) that KPL was largely independent of lipid type and temperature, (ii) that lipid diffusion rates in the polymers were higher compared to predictions based on their molecular volume, (iii) that silicones showed higher lipid diffusion and lower lipid sorption compared to LDPE and (iv) that absorbed lipid behaved like a co-solute and did not affect the partitioning of HOC at least for the smaller molecular size HOC. The obtained KPL can convert measured equilibrium concentrations in passive sampling polymers into equilibrium concentrations in lipid, which then can be used (1) for environmental quality monitoring and assessment, (2) for thermodynamic exposure assessment and (3) for assessing the linkage between passive sampling and the traditionally measured lipid-normalized concentrations in biota. LDPE-lipid partition coefficients may also be of use for a thermodynamically sound risk assessment of HOC contained in microplastics. Copyright © 2017. Published by Elsevier Ltd.

  19. Flexible and hydrophobic Zn-based metal-organic framework.

    Science.gov (United States)

    Hauptvogel, Ines Maria; Biedermann, Ralf; Klein, Nicole; Senkovska, Irena; Cadiau, Amandine; Wallacher, Dirk; Feyerherm, Ralf; Kaskel, Stefan

    2011-09-05

    A zinc-based metal-organic framework Zn(2)(adb)(2)(dabco)·4.5 DMF (K) (DUT-30(Zn), DUT = Dresden University of Technology, adb = 9,10-anthracene dibenzoate, dabco =1,4-diazabicyclo[2.2.2]octane, DMF = N,N-dimethylformamide) was synthesized using a solvothermal route. This MOF exhibits six crystallographic guest dependent phases. Two of them were characterized via single crystal X-ray analysis. The as-synthesized phase K crystallizes in the orthorhombic space group Fmmm, with a = 9.6349(9), b = 26.235(3), and c = 28.821(4) Å and consists of two interpenetrated pillar-layer networks with pcu topology. When the substance loses 0.5 DMF molecules per formula unit, a phase transition from the kinetic phase K to a thermodynamic phase T occurs. Zn(2)(adb)(2)(dabco)·4 DMF (T) crystallizes in the tetragonal space group I4/mmm, with a = 19.5316(8) and c = 9.6779(3) Å. During the evacuation the DUT-30(Zn) undergoes again the structural transformation to A. The activated compound A shows the gate pressure effect in the low pressure region of nitrogen physisorption isotherm and has a BET surface area of 960 m(2 )g(-1) and a specific pore volume of 0.43 cm(3) g(-1). Furthermore, DUT-30(Zn) exhibits a hydrogen storage capacity of 1.12 wt % at 1 bar, a CO(2) uptake of 200 cm(3) g(-1) at -78 °C and 0.9 bar, and a n-butane uptake of 3.0 mmol·g(-1) at 20 °C. The N(2) adsorption process was monitored in situ via X-ray powder diffraction using synchrotron radiation. A low temperature induced transformation of phase A to phase V could be observed if the compound was cooled under vacuum to -196 °C. A further crystalline phase N could be identified if the framework was filled with nitrogen at -196 °C. Additionally, the treatment of activated phase A with water leads to the new phase W.

  20. Thermal gelation of aqueous hydroxypropylmethylcellulose solutions with SDS and hydrophobic drug particles.

    Science.gov (United States)

    Acevedo, Aldo; Takhistov, Paul; de la Rosa, Carlos Pinzón; Florián, Vivian

    2014-02-15

    The thermal gelation of hydroxypropylmethylcellulose (HPMC) solutions has been studied as a function of sodium dodecyl sulfate (SDS) concentration with and without griseofulvin, a model particulate BCS Class II drug by rheological measurements of gelation temperature (Tgel), steady-state viscosity (η) at 25 °C, and ζ-potential. Polymer adsorption on the drug was demonstrated by a decrease in η and potential in the absence of SDS. Griseofulvin had a synergistic effect on gelation which was attributed to an effective spanning of associated hydrophobic polymeric regions through interactions with the adsorbed polymer. Adding SDS offsets this effect on Tgel shielding hydrophobic interactions. Higher SDS concentrations had no effect on the particles surface as evidenced by constant ζ-potential and Tgel. Yet, polymeric chains are saturated and larger surfactant aggregates account for the increase in viscosity. Understanding the gelation mechanism and complex interactions of HPMC with surfactants and drugs is necessary for the design of pharmaceutical products and optimization of their performance properties.

  1. Adsorption of HMF from water/DMSO solutions onto hydrophobic zeolites: experiment and simulation.

    Science.gov (United States)

    Xiong, Ruichang; León, Marta; Nikolakis, Vladimiros; Sandler, Stanley I; Vlachos, Dionisios G

    2014-01-01

    The adsorption of 5-hydroxymethylfurfural (HMF), DMSO, and water from binary and ternary mixtures in hydrophobic silicalite-1 and dealuminated Y (DAY) zeolites at ambient conditions was studied by experiments and molecular modeling. HMF and DMSO adsorption isotherms were measured and compared to those calculated using a combination of grand canonical Monte Carlo and expanded ensemble (GCMC-EE) simulations. A method based on GCMC-EE simulations for dilute solutions combined with the Redlich-Kister (RK) expansion (GCMC-EE-RK) is introduced to calculate the isotherms over a wide range of concentrations. The simulations, using literature force fields, are in reasonable agreement with experimental data. In HMF/water binary mixtures, large-pore hydrophobic zeolites are much more effective for HMF adsorption but less selective because large pores allow water adsorption because of H2 O-HMF attraction. In ternary HMF/DMSO/water mixtures, HMF loading decreases with increasing DMSO fraction, rendering the separation of HMF from water/DMSO mixtures by adsorption difficult. The ratio of the energetic interaction in the zeolite to the solvation free energy is a key factor in controlling separation from liquid mixtures. Overall, our findings could have an impact on the separation and catalytic conversion of HMF and the rational design of nanoporous adsorbents for liquid-phase separations in biomass processing.

  2. Influence of hydrophobic/hydrophilic fractions of extracellular organic matters of Microcystis aeruginosa on ultrafiltration membrane fouling.

    Science.gov (United States)

    Zhou, Shiqing; Shao, Yisheng; Gao, Naiyun; Li, Lei; Deng, Jing; Tan, Chaoqun; Zhu, Mingqiu

    2014-02-01

    Fouling is a major obstacle to maintain the efficiency of ultrafiltration-based drinking water treatment process. Algal extracellular organic matters (EOMs) are currently considered as one of the major sources of membrane fouling. The objective of this study was to investigate the influence of different hydrophobic/hydrophilic fractions of EOM extracted from Microcystis aeruginosa on ultrafiltration membrane fouling at lab scale. The experimental data indicated that EOM exhibited similar flux decline trends on polyethersulfone (PES) and regenerated cellulose (RC) membranes but caused greater irreversible fouling on PES membrane than RC membrane due to its hydrophobic property. It was also observed that charged hydrophilic (CHPI) and neutral hydrophilic (NHPI) fractions caused greater flux decline over hydrophobic (HPO) and transphilic (TPI) fractions. For PES membrane, the order of the irreversible fouling potentials for the four fractions was HPO>TPI>CHPI>NHPI, while the irreversible fouling potentials of RC membrane were tiny and could be ignored. Fluorescence excitation-emission matrix (EEM) spectra and Fourier transform infrared (FTIR) spectra suggested that protein-like, polysaccharide-like and humic-like substances were the major components responsible for membrane fouling. The results also indicated that the irreversible fouling increased as the pH decreased. The addition of calcium to feed solutions led to more severe flux decline and irreversible fouling.

  3. A simplified approach for monitoring hydrophobic organic contaminants associated with suspended sediment: Methodology and applications

    Science.gov (United States)

    Mahler, B.J.; Van Metre, P.C.

    2003-01-01

    Hydrophobic organic contaminants, although frequently detected in bed sediment and in aquatic biota, are rarely detected in whole-water samples, complicating determination of their occurrence, load, and source. A better approach for the investigation of hydrophobic organic contaminants is the direct analysis of sediment in suspension, but procedures for doing so are expensive and cumbersome. We describe a simple, inexpensive methodology for the dewatering of sediment and present the results of two case studies. Isolation of a sufficient mass of sediment for analyses of organochlorine compounds and PAHs is obtained by in-line filtration of large volumes of water. The sediment is removed from the filters and analyzed directly by standard laboratory methods. In the first case study, suspended-sediment sampling was used to determine occurrence, loads, and yields of contaminants in urban runoff affecting biota in Town Lake, Austin, TX. The second case study used suspended-sediment sampling to locate a point source of PCBs in the Donna Canal in south Texas, where fish are contaminated with PCBs. The case studies demonstrate that suspended-sediment sampling can be an effective tool for determining the occurrence, load, and source of hydrophobic organic contaminants in transport.

  4. A simplified approach for monitoring hydrophobic organic contaminants associated with suspended sediment: methodology and applications.

    Science.gov (United States)

    Mahler, B J; Van Metre, P C

    2003-04-01

    Hydrophobic organic contaminants, although frequently detected in bed sediment and in aquatic biota, are rarely detected in whole-water samples, complicating determination of their occurrence, load, and source. A better approach for the investigation of hydrophobic organic contaminants is the direct analysis of sediment in suspension, but procedures for doing so are expensive and cumbersome. We describe a simple, inexpensive methodology for the dewatering of sediment and present the results of two case studies. Isolation of a sufficient mass of sediment for analyses of organochlorine compounds and PAHs is obtained by in-line filtration of large volumes of water. The sediment is removed from the filters and analyzed directly by standard laboratory methods. In the first case study, suspended-sediment sampling was used to determine occurrence, loads, and yields of contaminants in urban runoff affecting biota in Town Lake, Austin, TX. The second case study used suspended-sediment sampling to locate a point source of PCBs in the Donna Canal in south Texas, where fish are contaminated with PCBs. The case studies demonstrate that suspended-sediment sampling can be an effective tool for determining the occurrence, load, and source of hydrophobic organic contaminants in transport.

  5. Hydrophobic Coatings on Cotton Obtained by in Situ Plasma Polymerization of a Fluorinated Monomer in Ethanol Solutions.

    Science.gov (United States)

    Molina, Ricardo; Teixidó, Josep Maria; Kan, Chi-Wai; Jovančić, Petar

    2017-02-15

    Plasma polymerization using hydrophobic monomers in the gas phase is a well-known technology to generate hydrophobic coatings. However, synthesis of functional hydrophobic coatings using plasma technology in liquids has not yet been accomplished. This work is consequently focused on polymerization of a liquid fluorinated monomer on cotton fabric initiated by atmospheric plasma in a dielectric barrier discharge configuration. Functional hydrophobic coatings on cotton were successfully achieved using in situ atmospheric plasma-initiated polymerization of fluorinated monomer dissolved in ethanol. Gravimetric measurements reveal that the amount of polymer deposited on cotton substrates can be modulated with the concentration of monomer in ethanol solution, and cross-linking reactions occur during plasma polymerization of a fluorinated monomer even without the presence of a cross-linking agent. FTIR and XPS analysis were used to study the chemical composition of hydrophobic coatings and to get insights into the physicochemical processes involved in plasma treatment. SEM analysis reveals that at high monomer concentration, coatings possess a three-dimensional pattern with a characteristic interconnected porous network structure. EDX analysis reveals that plasma polymerization of fluorinated monomers takes place preferentially at the surface of cotton fabric and negligible polymerization takes place inside the cotton fabric. Wetting time measurements confirm the hydrophobicity of cotton coatings obtained although equilibrium moisture content was slightly decreased. Additionally, the abrasion behavior and resistance to washing of plasma-coated cotton has been evaluated.

  6. Rheological Properties in Aqueous Solution for Hydrophobically Modified Polyacrylamides Prepared in Inverse Emulsion Polymerization

    Directory of Open Access Journals (Sweden)

    Shirley Carro

    2017-01-01

    Full Text Available Inverse emulsion polymerization technique was employed to synthesize hydrophobically modified polyacrylamide polymers with hydrophobe contents near to feed composition. Three different structures were obtained: multisticker, telechelic, and combined. N-Dimethyl-acrylamide (DMAM, n-dodecylacrylamide (DAM, and n-hexadecylacrylamide (HDAM were used as hydrophobic comonomers. The effect of the hydrophobe length of comonomer, the initial monomer, and surfactant concentrations on shear viscosity was studied. Results show that the molecular weight of copolymer increases with initial monomer concentration and by increasing emulsifier concentration it remained almost constant. Shear viscosity measurements results show that the length of the hydrophobic comonomer augments the hydrophobic interactions causing an increase in viscosity and that the polymer thickening ability is higher for combined polymers.

  7. FLUORESCENCE PROBING OF THE FORMATION OF HYDROPHOBIC MICRODOMAINS BY CROSS-LINKED POLY(ALKYLMETHYLDIALLYLAMMONIUM BROMIDES) IN AQUEOUS-SOLUTION

    NARCIS (Netherlands)

    WANG, GJ; ENGBERTS, J B F N

    Pyrene has been used as a fluorescence probe to investigate the conformational behavior of cross-linked poly(alkylmethyldiallylammonium bromides) in aqueous solutions. Binding of pyrene to hydrophobic microdomains, formed by the polysoaps, is reflected by a change in the ratio I-1/I-3 of the

  8. Adsorption of Halogenated Hydrocarbons from Aqueous Solutions by Wetted and Nonwetted Hydrophobic and Hydrophilic Sorbents:  Equilibria

    NARCIS (Netherlands)

    Rexwinkel, G.; Heesink, A.B.M.; Swaaij, van W.P.M.

    1999-01-01

    Single-solute adsorption equilibria of 1,1,1-trichloroethane, 1,1,2-trichloroethane, trichloroethene, trans-1,2-dichloroethene, chloroform, 2,4-dichorophenol, and dichloromethane dissolved in water have been measured, using both wetted and nonwetted hydrophobic Amberlite XAD-4 resin at 20 °C. The re

  9. Impact of organic modifier and temperature on protein denaturation in hydrophobic interaction chromatography.

    Science.gov (United States)

    Bobaly, Balázs; Beck, Alain; Veuthey, Jean-Luc; Guillarme, Davy; Fekete, Szabolcs

    2016-11-30

    The goal of this study was to better understand the chromatographic conditions in which monoclonal antibodies (mAbs) of broad hydrophobicity scale and a cysteine conjugated antibody-drug conjugate (ADCs), namely brentuximab-vedotin, could denaturate. For this purpose, some experiments were carried out in HIC conditions using various organic modifier in natures and proportions, different mobile phase temperatures and also different pHs. Indeed, improper analytical conditions in hydrophobic interaction chromatography (HIC) may create reversed-phase (RP) like harsh conditions and therefore protein denaturation. In terms of organic solvents, acetonitrile (ACN) and isopropanol (IPA) were tested with proportions ranging from 0 to 40%. It appeared that IPA was a less denaturating solvent than ACN, but should be used in a reasonable range (10-15%). Temperature should also be kept reasonable (below 40°C), to limit denaturation under HIC conditions. However, the combined increase of temperature and organic content induced denaturation of protein biopharmaceuticals in all cases. Indeed, above 30-40°C and 10-15% organic modifier in mobile phase B, heavy chain (HC) and light chain (LC) fragments dissociated. Mobile phase pH was also particularly critical and denaturation was significant even under moderately acidic conditions (pH of 5.4). Today, HIC is widely used for measuring drug-to-antibody ratio (DAR) of ADCs, which is a critical quality attribute of such samples. Here, we demonstrated that the estimation of average DAR can be dependent on the amount of organic modifier in the mobile phase under HIC conditions, due to the better recovery of the most hydrophobic proteins in presence of organic solvent (IPA). So, special care should be taken when measuring the average DAR of ADCs in HIC. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Organic-Inorganic Hydrophobic Nanocomposite Film with a Core-Shell Structure

    Directory of Open Access Journals (Sweden)

    Peng Liu

    2016-12-01

    Full Text Available A method to prepare novel organic-inorganic hydrophobic nanocomposite films was proposed by a site-specific polymerization process. The inorganic part, the core of the nanocomposite, is a ternary SiO2–Al2O3–TiO2 nanoparticles, which is grafted with methacryloxy propyl trimethoxyl silane (KH570, and wrapped by fluoride and siloxane polymers. The synthesized samples are characterized by transmission electron microscopy (TEM, Fourier transform infrared (FTIR spectrscopy, X-ray diffractometry (XRD, contact angle meter (CA, and scanning electron microscope (SEM. The results indicate that the novel organic-inorganic hydrophobic nanocomposite with a core-shell structure was synthesized successfully. XRD analysis reveals the nanocomposite film has an amorphous structure, and FTIR analysis indicates the nanoparticles react with a silane coupling agent (methacryloxy propyl trimethoxyl silane KH570. Interestingly, the morphology of the nanoparticle film is influenced by the composition of the core. Further, comparing with the film synthesized by silica nanoparticles, the film formed from SiO2–Al2O3–TiO2 nanoparticles has higher hydrophobic performance, i.e., the contact angle is greater than 101.7°. In addition, the TEM analysis reveals that the crystal structure of the particles can be changed at high temperatures.

  11. The extraction of uranium using graphene aerogel loading organic solution.

    Science.gov (United States)

    Chen, Mumei; Li, Zheng; Li, Jihao; Li, Jingye; Li, Qingnuan; Zhang, Lan

    2017-05-01

    A new approach for uranium extraction employing graphene aerogel (GA) as a skeleton loading organic solution (GA-LOS) is proposed and investigated. Firstly, the GA with super-hydrophobicity and high organic solution absorption capacity was fabricated by one-step reduction and self-assembly of graphene oxide with ethylenediamine. By adsorbing Tri-n-butyl phosphate (TBP)/n-dodecane solution to prepare GA-LOS, the extraction of U(VI) from nitric acid medium using GA-LOS was investigated and compared with conventional solvent extraction. It is found that the GA-LOS method can provide several advantages over conventional solvent extraction and adsorption due to the elimination of aqueous-organic mixing-separation procedures and easy solid-liquid separation. Furthermore, it also possesses higher extraction capacity (the saturated extraction capacity of GA loading TBP for U(VI) was 316.3mgg(-1) ) and lower consumption of organic diluents, leading to less organic waste. Moreover, the stability of GA-LOS in aqueous solution and cycling test were also studied, and it shows a remarkable regeneration capability, making it an ideal candidate for metal extraction from aqueous solution.

  12. Fouling and cleaning characteristics of ultrafiltration of hydrophobic dissolved organic matter by a polyvinyl chloride hollow fiber membrane.

    Science.gov (United States)

    Guo, Xiaoyan; Gao, Wei; Li, Jihui; Hu, Wanli

    2009-06-01

    Ultrafiltration membrane fouling is a significant problem in drinking water treatment. Many researchers believe that hydrophobic natural organic matter is the main foulant. In this research, fulvic acid, tannin, and aniline were used to represent hydrophobic acid, neutral, and base, respectively, to investigate modified polyvinyl chloride ultrafiltration membrane fouling characteristics. Four kinds of cleaning methods were used in this study: flushing, backwashing, flushing and backwashing, and chemical cleaning with 0.5% sodium hydroxide. Each was performed on the three hydrophobic dissolved organic matters (acid, neutral, and base) to identify the fouling mechanisms of polyvinyl chloride ultrafiltration membrane. Results showed that hydrophobic base fouled membranes the most and hydrophobic acid the least based on cleaning difficulty.

  13. Adaptive hydrophobic and hydrophilic interactions of mussel foot proteins with organic thin films.

    Science.gov (United States)

    Yu, Jing; Kan, Yajing; Rapp, Michael; Danner, Eric; Wei, Wei; Das, Saurabh; Miller, Dusty R; Chen, Yunfei; Waite, J Herbert; Israelachvili, Jacob N

    2013-09-24

    The adhesion of mussel foot proteins (Mfps) to a variety of specially engineered mineral and metal oxide surfaces has previously been investigated extensively, but the relevance of these studies to adhesion in biological environments remains unknown. Most solid surfaces exposed to seawater or physiological fluids become fouled by organic conditioning films and biofilms within minutes. Understanding the binding mechanisms of Mfps to organic films with known chemical and physical properties therefore is of considerable theoretical and practical interest. Using self-assembled monolayers (SAMs) on atomically smooth gold substrates and the surface forces apparatus, we explored the force-distance profiles and adhesion energies of three different Mfps, Mfp-1, Mfp-3, and Mfp-5, on (i) hydrophobic methyl (CH3)- and (ii) hydrophilic alcohol (OH)-terminated SAM surfaces between pH 3 and pH 7.5. At acidic pH, all three Mfps adhered strongly to the CH3-terminated SAM surfaces via hydrophobic interactions (range of adhesive interaction energy = -4 to -9 mJ/m(2)) but only weakly to the OH-terminated SAM surfaces through H- bonding (adhesive interaction energy ≤ -0.5 mJ/m(2)). 3, 4-Dihydroxyphenylalanine (Dopa) residues in Mfps mediate binding to both SAM surface types but do so through different interactions: typical bidentate H-bonding by Dopa is frustrated by the longer spacing of OH-SAMs; in contrast, on CH3-SAMs, Dopa in synergy with other nonpolar residues partitions to the hydrophobic surface. Asymmetry in the distribution of hydrophobic residues in intrinsically unstructured proteins, the distortion of bond geometry between H-bonding surfaces, and the manipulation of physisorbed binding lifetimes represent important concepts for the design of adhesive and nonfouling surfaces.

  14. Concentration and fractionation of hydrophobic organic acid constituents from natural waters by liquid chromatography

    Science.gov (United States)

    Thurman, E.M.; Malcolm, R.L.

    1979-01-01

    A scheme is presented which used adsorption chromatography with pH gradient elution and size-exclusion chromatography to concentrate and separate hydrophobic organic acids from water. A review of chromatographic processes involved in the flow scheme is also presented. Organic analytes which appear in each aqueous fraction are quantified by dissolved organic carbon analysis. Hydrophobic organic acids in a water sample are concentrated on a porous acrylic resin. These acids usually constitute approximately 30-50 percent of the dissolved organic carbon in an unpolluted water sample and are eluted with an aqueous eluent (dilute base). The concentrate is then passed through a column of polyacryloylmorpholine gel, which separates the acids into high- and low-molecular-weight fractions. The high- and low-molecular-weight eluates are reconcentrated by adsorption chromatography, then are eluted with a pH gradient into strong acids (predominately carboxylic acids) and weak acids (predominately phenolic compounds). For standard compounds and samples of unpolluted waters, the scheme fractionates humic substances into strong and weak acid fractions that are separated from the low molecular weight acids. A new method utilizing conductivity is also presented to estimate the acidic components in the methanol fraction.

  15. AFM study of forces between silicon oil and hydrophobic-hydrophilic surfaces in aqueous solutions.

    Science.gov (United States)

    Zbik, Marek S; Frost, Ray L

    2010-09-15

    An investigation has been made of the interactions between silicone oil and various solid substrates immersed in aqueous solutions. Measurements were made using an atomic force microscope (AFM) using the colloid-probe method. The silicone oil drop is simulated by coating a small silica sphere with the oil, and measuring the force as this coated sphere is brought close to contact with a flat solid surface. It is found that the silicone oil surface is negatively charged, which causes a double-layer repulsion between the oil drop and another negatively charged surface such as mica. With hydrophilic solids, this repulsion is strong enough to prevent attachment of the drop to the solid. However, with hydrophobic surfaces there is an additional attractive force which overcomes the double-layer repulsion, and the silicone oil drop attaches to the solid. There is circumstantial evidence that linear and nonlinear effect take part in force results from compression of the silicone oil film coated on the glass sphere.

  16. USE OF CATIONIC SURFACTANTS TO MODIFY SOIL SURFACES TO PROMOTE SORPTION AND RETARD MIGRATION OF HYDROPHOBIC ORGANIC COMPOUNDS

    Science.gov (United States)

    Cationic surfactants can be used to modify surfaces of soils and subsurface materials to promote adsorption of hydrophobic organic compounds (HOC). Batch and column experiments were performed to investigate this phenomenon with the cationic surfactant dodecylpyridinium (DP), a se...

  17. Adsorption Study of Several Hydrophobic Organic Contaminants on an Aquifer Material

    Directory of Open Access Journals (Sweden)

    Barbara Ruffino

    2009-01-01

    Full Text Available Problem statement: Aim of the present research was to determine coefficient of partition KD between soil and groundwater for five hydrophobic organic pollutants (benzene, chlorobenzene, trichloroethylene-TCE, perchloroethylene-PCE and toluene in an Italian aquifer material characterized by a low organic carbon content (fOC = 0.00262 by means of laboratory batch tests. Initial aqueous concentrations (quite different among the five compounds were representative of the pollution level of considered site. Approach: Adsorption data for five afore mentioned compounds were obtained by means of laboratory tests: Multi-contaminant adsorption tests were performed putting in contact 50 g of dried soil together with 200 mL of a contaminant solution for 72 h in order to achieve the equilibrium. After 72 h, supernatant was then analyzed by means of headspace gaschromatography providing the equilibrium concentration of the contaminants of interest in liquid phase. The concentration of contaminants of interest in solid phase (adsorbent was determined taking advantage of a mass balance performed on each contaminant. Results: Results showed that both linear isotherm (in form of Henry isotherm and Freundlich isotherm were able to fit experimental points for benzene, chlorobenzene, TCE and PCE in a satisfactory way; as for these four contaminants, PCE is more strongly adsorbed than TCE and TCE, in its turn, is more strongly adsorbed than benzene and chlorobenzene. On the other hand, Langmuir model appeared to be the most suitable in fitting toluene experimental points. The comparison between real distribution coefficient KD obtained fitting experimental points with an Henry-type isotherm and KD obtained on grounds of a theoretical model, like Linear Free Energy Relationships (LFER-based model, showed that LFER model uniformly underestimate the sorption process over whole concentration range, with the only exception of toluene. In case of toluene, LFER-based model

  18. Structural and rheological characterizations of nanoparticles of environment-sensitive hydrophobic alginate in aqueous solution.

    Science.gov (United States)

    Chen, Kai; Li, Jiacheng; Feng, Yuhong; He, Furui; Zhou, Qingfeng; Xiao, Dunchao; Tang, Yiyuan

    2017-01-01

    Amphiphilic polymers that form self-assembled structures in aqueous media have been investigated and used for the diagnosis and therapy of various diseases, including cancer. In our work, a series of environment-sensitive hydrophobic alginates (Ugi-Alg) with various weight-average molecular mass values (Mw~6.7×10(5)-6.7×10(4)g/mol) were synthesized via Ugi reaction. The structure of Ugi-Alg was characterized by (1)HNMR spectrometer. The electrostatic self-assembly of different molecular weight (Mw) and composition (M/G ratio) of Ugi-Alg chain under various Na(+) concentrations, was investigated by dynamic light scattering, electron spin resonance experiments, and transmission electron microscopy. Result showed that by comparing to other Ugi-Alg, the mid-Mw Ugi-Alg (Mw~2.8×10(5)g/mol) could form stable and homogeneous nanoparticles in low Na(+) concentration solution. However, G/M values exerted no obvious effect on nanoparticles structure. Additionally, steady-shear flow, thixotropy and dynamical viscoelasticity tests were performed to characterize the rheological behavior of Ugi-Alg aqueous solutions as influenced by Mw and M/G ratio. All of the samples exhibited a non-Newtonian shear-thinning behavior above a critical shear rate (γ̇c2). The greater the Mw, the more sensitive the temperature-dependent behavior will be. The upward-downward rheograms showed that all of the systems evaluated in this study displayed a hysteresis loop, indicating a strong thixotropic behavior, and the thixotropic of mid-Mw Ugi-Alg was the strongest. The dynamical viscoelastic properties were characterized by oscillatory frequency sweep, revealing the gel-like viscoelastic behavior of mid-low Ugi-Alg and the fluid-like viscoelastic behavior of high-Mw Ugi-Alg. Copyright © 2016. Published by Elsevier B.V.

  19. The effect of aqueous solutions of trimethylamine-N-oxide on pressure induced modifications of hydrophobic interactions.

    Science.gov (United States)

    Sarma, Rahul; Paul, Sandip

    2012-09-07

    To understand the mechanism of protein protection by the osmolyte trimethylamine-N-oxide (TMAO) at high pressure, using molecular dynamics (MD) simulations, solvation of hydrophobic group is probed in aqueous solutions of TMAO over a wide range of pressures relevant to protein denaturation. The hydrophobic solute considered in this study is neopentane which is a considerably large molecule. The concentrations of TMAO range from 0 to 4 M and for each TMAO concentration, simulations are performed at five different pressures ranging from 1 atm to 8000 atm. Potentials of mean force are calculated and the relative stability of solvent-separated state over the associated state of hydrophobic solute are estimated. Results suggest that high pressure reduces association of hydrophobic solutes. From computations of site-site radial distribution function followed by analysis of coordination number, it is found that water molecules are tightly packed around the nonpolar particle at high pressure and the hydration number increases with increasing pressure. On the other hand, neopentane interacts preferentially with TMAO over water and although hydration of neopentane reduces in presence of this osmolyte, TMAO does not show any tendency to prevent the pressure-induced dispersion of neopentane moieties. It is also observed that TMAO molecules prefer a side-on orientation near the neopentane surface, allowing its oxygen atom to form favorable hydrogen bonds with water while maintaining some hydrophobic contacts with neopentane. Analysis of hydrogen-bond properties and solvation characteristics of TMAO reveals that TMAO can form hydrogen bonds with water and it reduces the identical nearest neighbor water molecules caused by high hydrostatic pressures. Moreover, TMAO enhances life-time of water-water hydrogen bonds and makes these hydrogen bonds more attractive. Implication of these results for counteracting effect of TMAO against protein denaturation at high pressures are

  20. Feasibility study of silica sol as the carrier of a hydrophobic drug in aqueous solution using enrofloxacin as the model

    Energy Technology Data Exchange (ETDEWEB)

    Song Meirong, E-mail: smr770505@yahoo.com.cn [College of Sciences, Henan Agricultural University, Zhengzhou 450002 (China); Song Junling [School of Food, Henan Institute of Science and Technology, Xinxiang, 453003 (China); Ning Aimin [College of Sciences, Henan Agricultural University, Zhengzhou 450002 (China); Cui Baoan, E-mail: baoancui@henau.edu.cn [College of Sciences, Henan Agricultural University, Zhengzhou 450002 (China); Cui Shumin; Zhou Yaobing; An Wankai; Dong Xuesong; Zhang Gege [College of Sciences, Henan Agricultural University, Zhengzhou 450002 (China)

    2010-01-01

    The aim of this study was to determine the feasibility of using silica sol to carry a hydrophobic drug in aqueous solution. Enrofloxacin, which was selected as the model drug because it is a broad-spectrum antibiotic drug with poor solubility in water, was adsorbed onto silica sol in aqueous solution during cooling from 60 deg. C to room temperature. The drug-loaded silica sol was characterized by transmission electron microscopy, Fourier transform infrared spectrum, thermal gravimetric analysis and ultraviolet-visible light spectroscopy. The results showed that enrofloxacin was adsorbed by silica sol without degradation at a loading of 15.23 wt.%. In contrast to the rapid release from pure enrofloxacin, the drug-loaded silica sol showed a slower release over a longer time. Kinetics analysis suggested the drug release from silica sol was mainly a diffusion-controlled process. Therefore, silica sol can be used to carry a hydrophobic drug in aqueous solution for controlled drug delivery.

  1. Micelle swelling agent derived cavities for increasing hydrophobic organic compound removal efficiency by mesoporous micelle@silica hybrid materials

    KAUST Repository

    Shi, Yifeng

    2012-06-01

    Mesoporous micelle@silica hybrid materials with 2D hexagonal mesostructures were synthesized as reusable sorbents for hydrophobic organic compounds (HOCs) removal by a facile one-step aqueous solution synthesis using 3-(trimethoxysily)propyl-octadecyldimethyl-ammonium chloride (TPODAC) as a structure directing agent. The mesopores were generated by adding micelle swelling agent, 1,3,5-trimethyl benzene, during the synthesis and removing it afterward, which was demonstrated to greatly increase the HOC removal efficiency. In this material, TPODAC surfactant is directly anchored on the pore surface of mesoporous silica via SiOSi covalent bond after the synthesis due to its reactive Si(OCH 3) 3 head group, and thus makes the synthesized materials can be easily regenerated for reuse. The obtained materials show great potential in water treatment as pollutants sorbents. © 2011 Elsevier Inc. All rights reserved.

  2. Kinetic and equilibrium studies of the removal of cadmium ions from acidic chloride solutions by hydrophobic pyridinecarboxamide extractants

    Energy Technology Data Exchange (ETDEWEB)

    Borowiak-Resterna, Aleksandra [Institute of Chemical Technology and Engineering, Poznan University of Technology, Pl. Marii Sklodowskiej-Curie 2, 60-965 Poznan (Poland); Cierpiszewski, Ryszard [Poznan University of Economics, Faculty of Commodity Science, al. Niepodleglosci 10, 61-875 Poznan (Poland); Prochaska, Krystyna, E-mail: Krystyna.Prochaska@put.poznan.pl [Institute of Chemical Technology and Engineering, Poznan University of Technology, Pl. Marii Sklodowskiej-Curie 2, 60-965 Poznan (Poland)

    2010-07-15

    Liquid-liquid extraction of cadmium(II) from acidic chloride solutions was carried out with alkyl derivatives of pyridinecarboxamide in toluene with addition of 2-ethylhexan-1-ol as modifier. Equilibrium as well as kinetic studies was performed. The kinetic studies of a Cd(II) extraction process were carried out with a Lewis cell having a constant interfacial area. Cadmium(II) concentration in the aqueous phases was determined by atomic absorption spectroscopy (Varian SPECTR AA800). The results of equilibrium experiments showed that cadmium(II) was quantitatively extracted with N,N-dihexylpyridine-3-carboxamide whereas the derivative N,N-dihexylpyridine-2-carboxamide was not able to transfer Cd(II) ions from the aqueous phase to the organic one. Thus, the kinetics of extraction and the initial extraction rate were examined only in the systems with N,N-dihexylpyridine-3-carboxamide. The obtained experimental data as well as the calculated values of mass transfer coefficients suggest that the investigated process of extraction of Cd(II) by means of pyridinecarboxamide as extractant occurs in the mixed diffusion-kinetic region. Moreover, the results of adsorption studies indicated that the extraction of Cd(II) with a hydrophobic extractant should be considered as an interfacial process.

  3. Multiscale Modelling Approach for a Fungal Biofilter Unit for the Hydrophobic Abatement of Volatile Organic Compounds

    DEFF Research Database (Denmark)

    Vergara-Fernández, A.; Rebolledo-Castro, J.; Morales Rodriguez, Ricardo

    2011-01-01

    Currently, biofiltration has become a viable and potential alternative for the treatment of airstreams with low concentrations of hydrophobic volatile organic compounds (VOCs), which can employ to this end, diverse microorganisms (such as, bacteria, fungal or microbial consortia, etc.) growing...... a biofilm. Usually, the design, analysis and scale-up of this kind of units have been mainly done via experimental approach, which can be costly in terms of time and resources. Therefore, the objective of this work is to introduce mathematical model for the prediction and simulation of a fungal biofilter...

  4. Hydrophobization potential of organic compounds deriving from olive oil production waste water

    Science.gov (United States)

    Egerer, Sina E.; Bandow, Nicole; Marschner, Bernd; Schaumann, Gabriele E.

    2010-05-01

    Olive oil production waste water (OPWW) is rich in dissolved organic carbon and nutrients (e.g. potassium). In order to use it as organic fertilizer, small-scale and family run olive oil production farms in Israel and Palestine often discharge it directly onto agricultural land without any previous treatment. One unwanted side effect that can be observed is the development of soil water repellency (SWR) which is probably induced by amphiphilic substances. Previous studies on the composition of OPWW have shown that it contains oil components such as phenols, fats and large-molecular organic compounds (e.g. Gonzalezvila et al., 1995), some of which have been reported to induce water repellency on soil mineral surfaces (e.g. Ma'shum et al., 1988; Leelamanie and Karube, 2007). For prioritization of compounds the individual hydrophobization potential of 16 common OPWW components was systematically evaluated using the sessile drop and the Wilhelmy plate method. Acid-washed sand was taken as model soil mineral material. In a batch experiment OPWW samples from Israel and Palestine were applied to sand and two different soils in order to investigate their hydrophobization potential under different temperature and humidity conditions. To facilitate the identification of the chemicals responsible for inducing SWR, a fractionation procedure was applied to fraction the OPWW samples using solvents of different polarity. The prioritized compounds were analyzed by GC-MS. First results of this identification will be presented as well.

  5. Structure Prediction Based on Hydrophobic to Hydrophilic Volume Ratios in Small Molecule Amphiphilic Organic Crystals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The structure type for the crystal of 4,4'-bis-(2-hydroxy-ethoxyl)-biphenyl 1 has been predicted by using the previously developed interfacial model for small organic molecules. Based on the calculated hydrophobic to hydrophilic volume of 1, this model predicts the crystal structure to be of lamellar or bicontinuous type, which has been confirmed by the X-ray single-crystal structure analysis (C20H26O6, monoclinic, P21/c, a = 16.084(1), b = 6.0103(4), c = 9.6410(7)(A), β = 103.014(2)°, V = 908.1(1)(A)3, Z = 2, Dc = 1.325 g/cm3, F(000)=388, μ = 0.097 mm-1, MoKα radiation, λ = 0.71073 (A), R = 0.0382 and wR = 0.0882 with I > 2σ(I) for 7121 reflections collected, 1852 unique reflections and 170 parameters). As predicted, the hydrophobic and hydrophilic portions of 1 form in the lamellae. The same interfacial model is applied to other amphilphilic small molecule organic systems for structural type prediction.

  6. Hydrophobic Organic Hole Transporters for Improved Moisture Resistance in Metal Halide Perovskite Solar Cells.

    Science.gov (United States)

    Leijtens, Tomas; Giovenzana, Tommaso; Habisreutinger, Severin N; Tinkham, Jonathan S; Noel, Nakita K; Kamino, Brett A; Sadoughi, Golnaz; Sellinger, Alan; Snaith, Henry J

    2016-03-09

    Solar cells based on organic-inorganic perovskite semiconductor materials have recently made rapid improvements in performance, with the best cells performing at over 20% efficiency. With such rapid progress, questions such as cost and solar cell stability are becoming increasingly important to address if this new technology is to reach commercial deployment. The moisture sensitivity of commonly used organic-inorganic metal halide perovskites has especially raised concerns. Here, we demonstrate that the hygroscopic lithium salt commonly used as a dopant for the hole transport material in perovskite solar cells makes the top layer of the devices hydrophilic and causes the solar cells to rapidly degrade in the presence of moisture. By using novel, low cost, and hydrophobic hole transporters in conjunction with a doping method incorporating a preoxidized salt of the respective hole transporters, we are able to prepare efficient perovskite solar cells with greatly enhanced water resistance.

  7. A Low Cost and Facile Preparation of Hydrophobic Silica Films and Powders by a Solution-based Process

    Institute of Scientific and Technical Information of China (English)

    TIAN Tian; Tao Haizheng; XIAO Jing; XU Xinyi; An Jiming

    2015-01-01

    Super-hydrophobic surfaces with water contact angle (WCA) higher than 150° generated a lot of interests both in academic and in industry because of their self-cleaning functionality. Emphasis was given to the effect of pH value on the hydrophobic behavior of the obtainedfi lms or powders. Atfi rst, SiO2sols were prepared by diluted ammonia. We found that following the increase of pH value of sol from 8 to 9, WCAs of the obtainedfi lms increased from 121.8° to 131.8°. Following the continued increase of the pH value of sol, precipitates began to appear and smoothfi lm could not be obtained. The WCAs of the obtained powders could reach 121.7°, and through modifying by TMCS could further increase to as high as 165° and the water sliding angle (WSA) was 2°. The results of SEM indicate that the hydrophobic properties of the powders without modifying by TMCS should be originated from the formation of nano/micron binary structure,i e, a micron-scale diameter and a nano-scale surface roughness. In this work we provide a better solution to fabricate super-hydrophobic silica coating surface with a simple method at low cost.

  8. Synthesis of a highly hydrophobic cyclic decapeptide by solid-phase synthesis of linear peptide and cyclization in solution

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A general method was described to synthesize a highly hydrophobic cyclic peptide,cyclo[LWLWLWLWLQ]where underlines indicate D-configuration of the amino acid,by a two-step solid-phase/solution synthesis strategy.The linear decapeptide was assembled by standard Boc chemistry on solid-phase and subsequently cyclized in solution with high efficiency and reproducibility. In subsequent purification by semi-preparative HPLC,50%(v/v) DMF/H_2O was employed as the solvent to overcome the difficulty of solubilizat...

  9. Evaluation of persistent hydrophobic organic compounds in the Columbia River Basin using semipermeable-membrane devices

    Science.gov (United States)

    McCarthy, K.A.; Gale, R.W.

    2001-01-01

    Persistent hydrophobic organic compounds are of concern in the Columbia River because they have been correlated with adverse effects on wildlife. We analysed samples from nine main-stem and six tributary sites throughout the Columbia River Basin (Washington and Oregon) for polychlorinated dibenzo-p-dioxins, dibenzofurans, polychlorinated biphenyls, organochlorine pesticides, and priority-pollutant polycyclic aromatic hydrocarbons. Because these compounds may have important biological consequences at aqueous concentrations well below the detection limits associated with conventional sampling methods, we used semipermeable-membrane devices to sample water and achieved parts-per-quintillion detection limits. All of these compound classes were prevalent within the basin, but concentrations of many analytes were highest in the vicinity of Portland-Vancouver, indicating that the Willamette subbasin-and perhaps the urban area in particular-is an important source of these compounds. Data collected during basin low-flow conditions in 1997 and again during basin high-flow conditions in 1998 indicate that in-stream processes such as dilution by relatively clean inflow, and flow through island hyporheic zones may be important mechanisms for attenuating dissolved concentrations of hydrophobic compounds.

  10. Physisorption of hydroxide ions from aqueous solution to a hydrophobic surface

    NARCIS (Netherlands)

    Zangi, R; Engberts, JBFN

    2005-01-01

    We present results from detailed molecular dynamics simulations revealing a counterintuitive spontaneous physical adsorption of hydroxide ions at a water/hydrophobic interface. The driving force for the migration of the hydroxide ions from the aqueous phase is the preferential orientation of the

  11. Colorful Hydrophobic Poly(Vinyl Butyral)/Cationic Dye Fibrous Membranes via a Colored Solution Electrospinning Process

    Science.gov (United States)

    Yan, Xu; You, Ming-Hao; Lou, Tao; Yu, Miao; Zhang, Jun-Cheng; Gong, Mao-Gang; Lv, Fu-Yan; Huang, Yuan-Yuan; Long, Yun-Ze

    2016-12-01

    Colorful nanofibrous membranes have attracted much attention for their visual varieties and various functionalities. In this article, a colored solution electrospinning process was used to fabricate colorful hydrophobic poly(vinyl butyral) (PVB)/cationic dye nanofibrous membranes (NFMs) successfully. The color and morphology of these as-spun nanofibrous membranes have been analyzed by colorimetry, spectroscopy, and scanning electron microscopy (SEM). It is shown that the as-spun colorful PVB-based membranes exhibit excellent level-dyeing property and color stability. Furthermore, the doping of cationic dye and the increase of dye concentration can decrease the diameter of the as-spun colored fibers, which results in better level-dyeing property and higher water contact angle more than 140°. The stained PVB fibrous membranes with excellent level-dyeing property and hydrophobicity are promising in some applications such as textiles, wallpapers, and anticorrosive coating/painting.

  12. Rheological Properties of the Aqueous Solution for Fluorocarbon-containing Hydrophobically Modified Sodium PolyacrylicAcid with Various Surfactants

    Institute of Scientific and Technical Information of China (English)

    GUO,Jin-Feng(郭金峰); ZHUANG,Dong-Qing(庄东青); ZHOU,Hui(周晖); ZHANG,Yun-Xiang(章云祥)

    2001-01-01

    The interaction of fluorocarbon-containing hydrophobicallymodified sodiun polyacryiic acid (FMPAANa) (0.5 wt% )with various surfactants (anionic,nonionic and cationic) hasbeen investigated by theological measurements.Different rhe-ological behaviors are displayed for ionic surfactants and non-ionic surfactants.Fluorinated surfactants have stronger affini-ty with polyelectrolyte hydrophobes comparing with hydro-genated surfactants.The hydrophobic association of FM-PAANa with a cationic surfactant (CTAB) and a fluorinatednonionic surfactant (FC171) is much stronger than with anonionic surfactant (NP7.5 ) and an anionic surfactant(FC143).Further investigation of the effects of temperatureon solution properties shows that the dissociation energy Em iscorrelated to the strength of the aggregated junctions.``

  13. Amphiphilic organic ion pairs in solution: a theoretical study.

    Science.gov (United States)

    Pradines, Vincent; Poteau, Romuald; Pimienta, Veronique

    2007-07-16

    The macroscopic manifestation of hydrophobic interactions for amphiphilic organic ion pairs (tetraalkylammonium-anion) has been shown experimentally by measuring their association constants and their affinity with the organic phase. Beyond a certain size, there is a direct relation between association constants and chain lengths in tetraalkylammonium ions. We propose to cast a bridge between these results and geometrical properties considered at the level of a single ion pair by means of quantum chemistry calculations performed on model systems: trimethylalkylammonium-pentyl sulfate instead of tetraalkylammonium-dodecyl sulfate. Two limiting cases are considered: head-to-head configurations, which yield an optimal electrostatic interaction between polar heads, and parallel configurations with a balance between electrostatic and hydrophobic interactions. All properties (geometries, complexation energies, and atomic charges) were obtained at the MP2 level of calculation, with water described by a continuum model (CPCM). Dispersion forces link hydrocarbon chains of tetraalkylammonium ions and pentyl sulfate, thus yielding (for the largest ion pairs) parallel configurations favored with respect to head-to-head geometries by solute-solvent electrostatic interactions. Given the small experimental association energies, we probe the accuracy limit of the MP2 and CPCM methods. However, clear trends are obtained as a function of chain length, which agree with the experimental observations. The calculated monotonic stabilization of ion pairs when the hydrocarbon chain increases in length is discussed in terms of electrostatic interactions (between ions and between ion pairs and water), dispersion forces, and cavitation energies.

  14. Ion-exchange and hydrophobic interactions affecting selectivity for neutral and charged solutes on three structurally similar agglomerated ion-exchange and mixed-mode stationary phases.

    Science.gov (United States)

    Kazarian, Artaches A; Taylor, Mark R; Haddad, Paul R; Nesterenko, Pavel N; Paull, Brett

    2013-11-25

    The nature and extent of mixed-mode retention mechanisms evident for three structurally related, agglomerated, particle-based stationary phases were evaluated. These three agglomerated phases were Thermo Fisher ScientificIon PacAS11-HC - strong anion exchange, Thermo Fisher Scientific IonPac CS10--strong cation-exchange PS-DVB, and the Thermo Fisher Scientific Acclaim Trinity P1silica-based substrate, which is commercially marketed as a mixed-mode stationary phase. All studied phases can exhibit zwitterionic and hydrophobic properties, which contribute to the retention of charged organic analytes. A systematic approach was devised to investigate the relative ion-exchange capacities and hydrophobicities for each of the three phases, together with the effect of eluent pH upon selectivity, using a specifically selected range of anionic, cationic and neutral aromatic compounds. Investigation of the strong anion-exchange column and the Trinity P1 mixed-mode substrate, in relation to ion-exchange capacity and pH effects, demonstrated similar retention behaviour for both the anionic and ampholytic solutes, as expected from the structurally related phases. Further evaluation revealed that the ion-exchange selectivity of the mixed-mode phase exhibited properties similar to that of the strong anion-exchange column, with secondary cation-exchange selectivity, albeit with medium to high anion-exchange and cation-exchange capacities, allowing selective retention for each of the anionic, cationic and ampholytic solutes. Observed mixed-mode retention upon the examined phases was found to be a sum of anion- and cation-exchange interactions, secondary ion-exchange and hydrophobic interactions, with possible additional hydrogen bonding. Hydrophobic evaluation of the three phases revealed logP values of 0.38-0.48, suggesting low to medium hydrophobicity. These stationary phases were also benchmarked against traditional reversed-phase substrates namely, octadecylsilica YMC-Pac Pro C18

  15. Removal of Organic Dyes from Aqueous Solutions with Surfactant-Modified Magnetic Nanoparticles

    OpenAIRE

    Wybieralska Katarzyna; Wajda Anna

    2014-01-01

    The paper presents the results of studies on the possibility of using magnetic nanoparticles modified with selected hydrophobic surfactants for model post-production water purification. Colloidal solutions of iron hydroxide (III) and iron oxide (II and III) were obtained and their particles were subjected to surface modification using surfactants. Thus obtained magnetic fluids were used as active agents in the process of removing selected organic dyes from their aqueous solutions. The effecti...

  16. Preparation and Characterization of a Hydrophobic Metal-Organic Framework Membrane Supported on Thin Porous Metal Sheet

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jian; Canfield, Nathan L.; Liu, Wei

    2016-02-29

    A hydrophobic metal-organic framework (MOF) UiO-66-CH3 is prepared and its solvothermal stability is investigated in comparison to UiO-66. It is confirmed that the MOF stability is enhanced by introduction of the two methyl groups, while the water adsorption is reduced. Given its hydrophobicity and stability, UiO-66-CH3 is proposed as an attractive membrane material for gas separation under moisture conditions. The UiO-66-CH3 membrane is prepared on a 50µm-thin porous Ni support sheet for the first time by use of a secondary growth method. It is found that uniform seed coating on the support is necessary to form a continuous membrane. In addition to growth time and temperature, presence of a modulator in the growth solution is found to be useful for controlling hydrothermal membrane growth on the seeded support. A dense, inter-grown membrane layer is formed by 24-h growth over a temperature range from 120 oC to 160 oC. The membrane surface comprises 500 nm octahedral crystals, which are supposed to grow out of the original 100 nm spherical seeding crystals. The separation characteristics of resulting membranes are tested with pure CO2, air, CO2/air mixture, and humid CO2/air mixture. CO2 permeance as high as 1.9E-06 mol/m2/s/Pa at 31oC is obtained. Unlike the hydrophilic zeolite membranes, CO2 permeation through this membrane is not blocked by the presence of water vapor in the feed gas. The results suggest that this MOF framework is a promising membrane material worth to be further investigated for separation of CO2 and other small molecules from humid gas mixtures.

  17. The potential applications of using compost chars for removing the hydrophobic herbicide atrazine from solution

    Science.gov (United States)

    Tsui, L.; Roy, W.R.

    2008-01-01

    One commercial compost sample was pyrolyzed to produce chars as a sorbent for removing the herbicide atrazine from solution. The sorption behavior of compost-based char was compared with that of an activated carbon derived from corn stillage. When compost was pyrolyzed, the char yield was greater than 45% when heated under air, and 52% when heated under N2. In contrast, when the corn stillage was pyrolyzed under N2, the yield was only 22%. The N2-BET surface area of corn stillage activated carbon was 439 m2/g, which was much greater than the maximum compost char surface area of 72 m2/g. However, the sorption affinity of the compost char for dissolved atrazine was comparable to that of the corn stillage activated carbon. This similarity could have resulted from the initial organic waste being subjected to a relatively long period of thermal processes during composting, and thus, the compost was more thermally stable when compared with the raw materials. In addition, microorganisms transformed the organic wastes into amorphous humic substances, and thus, it was likely that the microporisity was enhanced. Although this micropore structure could not be detected by the N2-BET method, it was apparent in the atrazine sorption experiment. Overall, the experimental results suggested that the compost sample in current study was a relatively stable material thermally for producing char, and that it has the potential as a feed stock for making high-quality activated carbon. ?? 2007 Elsevier Ltd. All rights reserved.

  18. Theoretical study on the hydrophobic and hydrophilic hydration on large solutes: The case of phthalocyanines in water.

    Science.gov (United States)

    Martín, Elisa I; Martínez, José M; Sánchez Marcos, Enrique

    2015-07-28

    A theoretical study on the hydration phenomena of three representative Phthalocyanines (Pcs): the metal-free, H2Pc, and the metal-containing, Cu-phthalocyanine, CuPc, and its soluble sulphonated derivative, [CuPc(SO3)4](4-), is presented. Structural and dynamic properties of molecular dynamics trajectories of these Pcs in solution were evaluated. The hydration shells of the Pcs were defined by means of spheroids adapted to the solute shape. Structural analysis of the axial region compared to the peripheral region indicates that there are no significant changes among the different macrocycles, but that of [CuPc(SO3)4](4-), where the polyoxoanion presence induces a typically hydrophilic hydration structure. The analyzed water dynamic properties cover mean residence times, translational and orientational diffusion coefficients, and hydrogen bond network. These properties allow a thorough discussion about the simultaneous existence of hydrophobic and hydrophilic hydration in these macrocycles, and indicate the trend of water structure to well define shells in the environment of hydrophobic solutes. The comparison between the structural and dynamical analysis of the hydration of the amphipathic [CuPc(SO3)4](4-) and the non-soluble Cu-Pc shows a very weak coupling among the hydrophilic and hydrophobic fragments of the macrocycle. Quantitative results are employed to revisit the iceberg model proposed by Frank and Evans, leading to conclude that structure and dynamics support a non-strict interpretation of the iceberg view, although the qualitative trends pointed out by the model are supported.

  19. Role of a Hydrophobic Pocket in Polyamine Interactions with the Polyspecific Organic Cation Transporter OCT3.

    Science.gov (United States)

    Li, Dan C; Nichols, Colin G; Sala-Rabanal, Monica

    2015-11-13

    Organic cation transporter 3 (OCT3, SLC22A3) is a polyspecific, facilitative transporter expressed in astrocytes and in placental, intestinal, and blood-brain barrier epithelia, and thus elucidating the molecular mechanisms underlying OCT3 substrate recognition is critical for the rational design of drugs targeting these tissues. The pharmacology of OCT3 is distinct from that of other OCTs, and here we investigated the role of a hydrophobic cavity tucked within the translocation pathway in OCT3 transport properties. Replacement of an absolutely conserved Asp by charge reversal (D478E), neutralization (D478N), or even exchange (D478E) abolished MPP(+) uptake, demonstrating this residue to be obligatory for OCT3-mediated transport. Mutations at non-conserved residues lining the putative binding pocket of OCT3 to the corresponding residue in OCT1 (L166F, F450L, and E451Q) reduced the rate of MPP(+) transport, but recapitulated the higher sensitivity pharmacological profile of OCT1. Thus, interactions of natural polyamines (putrescine, spermidine, spermine) and polyamine-like potent OCT1 blockers (1,10-diaminodecane, decamethonium, bistriethylaminodecane, and 1,10-bisquinuclidinedecane) with wild-type OCT3 were weak, but were significantly potentiated in the mutant OCT3s. Conversely, a reciprocal mutation in OCT1 (F161L) shifted the polyamine-sensitivity phenotype toward that of OCT3. Further analysis indicated that OCT1 and OCT3 can recognize essentially the same substrates, but the strength of substrate-transporter interactions is weaker in OCT3, as informed by the distinct makeup of the hydrophobic cleft. The residues identified here are key contributors to both the observed differences between OCT3 and OCT1 and to the mechanisms of substrate recognition by OCTs in general.

  20. Surfactant-Free Solid Dispersions of Hydrophobic Drugs in an Amorphous Sugar Matrix Dried from an Organic Solvent.

    Science.gov (United States)

    Takeda, Koji; Gotoda, Yuto; Hirota, Daichi; Hidaka, Fumihiro; Sato, Tomo; Matsuura, Tsutashi; Imanaka, Hiroyuki; Ishida, Naoyuki; Imamura, Koreyoshi

    2017-03-06

    The technique for homogeneously dispersing hydrophobic drugs in a water-soluble solid matrix (solid dispersion) is a subject that has been extensively investigated in the pharmaceutical industry. Herein, a novel technique for dispersing a solid, without the need to use a surfactant, is reported. A freeze-dried amorphous sugar sample was dissolved in an organic solvent, which contained a soluble model hydrophobic component. The suspension of the sugar and the model hydrophobic component was vacuum foam dried to give a solid powder. Four types of sugars and methanol were used as representative sugars and the organic medium. Four model drugs (indomethacin, ibuprofen, gliclazide, and nifedipine) were employed. Differential scanning calorimetry analyses indicated that the sugar and model drug (100:1) did not undergo segregation during the drying process. The dissolution of the hydrophobic drugs in water from the solid dispersion was then evaluated, and the results indicated that the Cmax and AUC0-60 min of the hydrophobic drug in water were increased when the surfactant-free solid dispersion was used. Palatinose and/or α-maltose were superior to the other tested carbohydrates in increasing Cmax and AUC0-60 min for all tested model drugs, and the model drug with a lower water solubility tended to exhibit a greater extent of over-dissolution.

  1. Evaluation of low-cost materials for sorption of hydrophobic organic pollutants in stormwater.

    Science.gov (United States)

    Björklund, Karin; Li, Loretta

    2015-08-15

    Conventional stormwater treatment techniques such as sedimentation and filtration are inefficient for removing the dissolved and colloidal phases of hydrophobic organic compounds (HOCs) present in stormwater. Adsorption could be a promising technique for removing colloidal and dissolved pollutants. Five low-cost sorbent materials were investigated in this project, including two minerals – vermiculite and perlite – and three waste products – two pine barks and a sawdust – as potential adsorbents for removal of polycyclic aromatic hydrocarbons (PAHs), alkylphenols and phthalates; HOCs commonly found in stormwater. Adsorption capacity and kinetics were studied through batch adsorption tests using synthetic stormwater spiked with a mixture of HOCs. Vermiculite and perlite exhibited insignificant removal of the organic contaminants. The three wood-based materials retained >80% of the initial HOC concentration (10-300 μg/L). The two barks exhibited slightly higher adsorption capacities of HOCs than the sawdust. For all compounds tested, maximum adsorption onto the wood-based media was reached in materials and should be investigated in future studies through repeated adsorption of HOCs, for example in column studies.

  2. Isolation of Renewable Phenolics by Adsorption on Ultrastable Hydrophobic MIL-140 Metal-Organic Frameworks.

    Science.gov (United States)

    Van de Voorde, Ben; Damasceno Borges, Daiane; Vermoortele, Frederik; Wouters, Robin; Bozbiyik, Belgin; Denayer, Joeri; Taulelle, Francis; Martineau, Charlotte; Serre, Christian; Maurin, Guillaume; De Vos, Dirk

    2015-09-21

    The isolation and separation of phenolic compounds from aqueous backgrounds is challenging and will gain in importance as we become more dependent on phenolics from lignocellulose-derived bio-oil to meet our needs for aromatic compounds. Herein, we show that highly stable and hydrophobic Zr metal-organic frameworks of the MIL-140 type are effective adsorbent materials for the separation of different phenolics and far outperform other classes of porous solids (silica, zeolites, carbons). The mechanism of the hydroquinone-catechol separation on MIL-140C was studied in detail by combining experimental results with computational techniques. Although the differences in adsorption enthalpy between catechol and hydroquinone are negligible, the selective uptake of catechol in MIL-140C is explained by its dense π-π stacking in the pores. The interplay of enthalpic and entropic effects allowed separation of a complex, five-compound phenol mixture through breakthrough over a MIL-140C column. Unlike many other metal-organic frameworks, MIL-140C is remarkably stable and maintained structure, porosity and performance after five adsorption-desorption cycles.

  3. Understanding organic reactions in water : from hydrophobic encounters to surfactant aggregates

    NARCIS (Netherlands)

    Engberts, J.B.F.N.; Blandamer, M.J.

    2001-01-01

    A crucial factor in realising a green chemical process in solution involves the choice of a safe, non-toxic and cheap solvent. Water is the obvious choice. Despite solubility problems, considerable interest has developed recently in organic chemistry in water. This interest also results from the fac

  4. Hydrophobic organic contaminants in surficial sediments of Baltimore Harbor: Inventories and sources

    Energy Technology Data Exchange (ETDEWEB)

    Ashley, J.T.F.; Baker, J.E. [Univ. System of Maryland, Solomons, MD (United States). Chesapeake Biological Lab.

    1999-05-01

    The heavily urbanized and industrialized Baltimore Harbor/Patapsco River/Back River system is one of the most highly contaminated regions of the Chesapeake Bay. In June 1996, surficial sediments were collected at 80 sites throughout the subestuarine system, including historically undersampled creek sand embayments. The samples were analyzed for a suite of hydrophobic organic contaminants (HOCs) consisting of 32 polycyclic aromatic hydrocarbons (PAHs) and 113 polychlorinated biphenyl (PCB) congeners. Total PAH and total PCB concentrations ranged from 90 to 46,200 and 8 to 2,150 ng/g dry weight, respectively. There was enormous spatial variability in the concentrations of HOCs, which was not well correlated to grain size or organic carbon content, suggesting nonequilibrium partitioning and/or proximity to sources as important factors explaining the observed spatial variability. High concentrations of both classes of HOCs were localized around major urban stormwater runoff discharges. Elevated PAH concentrations were also centered around the Sparrow`s Point Industrial Complex, most likely a result of the pyrolysis of coal during the production of steel. All but 1 of the 80 sites exceeded the effects range-low (ERL) for total PCBs and, of those sites, 40% exceeded the effects range-medium (ERM), suggesting toxicity to marine benthic organisms would frequently occur. Using principal component analysis, differences in PAH signatures were discerned. Higher molecular weight PAHs were enriched in signatures from sediments close to suspected sources (i.e., urban stormwater runoff and steel production complexes) compared to those patterns observed at sites further from outfalls or runoff. Due to varying solubilities and affinities for organic matter of the individual PAHs, partitioning of the heavier weight PAHs may enrich settling particles with high molecular weight PAHs. Lower molecular weight PAHs, having lower affinity for particles, may travel from the source to a

  5. Polymer-coated nanoparticles: Carrier platforms for hydrophobic water- and air-sensitive metallo-organic compounds.

    Science.gov (United States)

    Valdeperez, Daniel; Wang, Tianqiang; Eußner, Jens P; Weinert, Bastian; Hao, Jianyuan; Parak, Wolfgang J; Dehnen, Stefanie; Pelaz, Beatriz

    2017-03-01

    Many of the relevant compounds for anticancer therapy are metal-based compounds (metallodrugs), being platinum-based drugs such as cisplatin, carboplatin (Paraplatin(®)), and oxaliplatin (Eloxatin(®)) the most widely used. Despite this, their application is limited by issues such as cell-acquired platinum resistance and manifold side effects following systemic delivery. Thus, the development of new metal-based compounds is highly needed. The catalytic properties of a variety of metal-based compounds are nowadays very well known, which opens new opportunities to take advantage of them inside living cells or organisms. However, many of these compounds are hydrophobic and thus not soluble in aqueous solution, as they lack stability against water or oxygen presence. Thus, versatile platforms capable of enhancing the features of these compounds in aqueous solutions are of importance in the development of new drugs. Surface engineered nanoparticles may render metallodrugs with good colloidal stability in water and in complex media containing high salt concentration and/or proteins. Herein, polymer coated nanoparticles are proposed as a platform to link insoluble and water/oxygen sensitive drugs. The linkage of insoluble and oxygen sensitive tin clusters to nanoparticles is presented, aiming to enhance both, the solubility and the stability of these compounds in water, which may be an alternative approach in the development of metal-based drugs. The formation of the cluster-nanoparticle system was confirmed via inductively coupled plasma mass spectrometry experiments. The catalytic activity and the stability of the cluster in water were studied through the reduction of methylene blue. Results demonstrate that in fact the tin clusters could be transferred into aqueous solution and retained their catalytic activity.

  6. ENVIRONMENTAL RESEARCH BRIEF: USE OF CATIONIC SURFACTANTS TO MODIFY AQUIFER MATERIALS TO REDUCE THE MOBILITY OF HYDROPHOBIC ORGANIC COMPOUNDS

    Science.gov (United States)

    Cationic surfactants can be used to modify surfaces of soils and subsurface materials to promote sorption of hydrophobic organic compounds (HOC) and retard their migration. For example, cationic surfactants could be injected into an aquifer downgradient from a source of HOC conta...

  7. Thermally stable hydrophobicity in electrospun silica/polydimethylsiloxane hybrid fibers

    Science.gov (United States)

    Wei, Zhonglin; Li, Jianjun; Wang, Chao; Cao, Jungang; Yao, Yongtao; Lu, Haibao; Li, Yibin; He, Xiaodong

    2017-01-01

    In order to improve practical performances of silica-based inorganic/organic hybrid fibers, silica/polydimethylsiloxane hydrophobic fibers were successfully prepared by electrospinning. Silica sol and polydimethylsiloxane can be mixed homogeneously and become stable precursor solution in dichloromethane, which allows the transformation of silica/polydimethylsiloxane precursor solution into ultrafine fibers. Flame can ignite organic groups in polydimethylsiloxane directly and destroy the hydrophobicity of hybrid fibers, but hydrophobic feature may survive if electrospun hybrid membrane is combined with thin stainless-steel-304 gauze of 150 meshes due to its thermally stable hydrophobicity (>600 °C).

  8. Selective on site separation and detection of molecules in diluted solutions with super-hydrophobic clusters of plasmonic nanoparticles

    KAUST Repository

    Gentile, Francesco T.

    2014-01-01

    Super-hydrophobic surfaces are bio-inspired interfaces with a superficial texture that, in its most common evolution, is formed by a periodic lattice of silicon micro-pillars. Similar surfaces reveal superior properties compared to conventional flat surfaces, including very low friction coefficients. In this work, we modified meso-porous silicon micro-pillars to incorporate networks of metal nano-particles into the porous matrix. In doing so, we obtained a multifunctional-hierarchical system in which (i) at a larger micrometric scale, the super-hydrophobic pillars bring the molecules dissolved in an ultralow-concentration droplet to the active sites of the device, (ii) at an intermediate meso-scale, the meso-porous silicon film adsorbs the low molecular weight content of the solution and, (iii) at a smaller nanometric scale, the aggregates of silver nano-particles would measure the target molecules with unprecedented sensitivity. In the results, we demonstrated how this scheme can be utilized to isolate and detect small molecules in a diluted solution in very low abundance ranges. The presented platform, coupled to Raman or other spectroscopy techniques, is a realistic candidate for the protein expression profiling of biological fluids. © 2014 the Partner Organisations.

  9. Nanoparticle-supported lipid bilayers as an in situ remediation strategy for hydrophobic organic contaminants in soils.

    Science.gov (United States)

    Wang, Hairong; Kim, Bojeong; Wunder, Stephanie L

    2015-01-06

    Polycyclic aromatic hydrocarbons (PAHs) are persistent environmental organic contaminants due to their low water solubility and strong sorption onto organic/mineral surfaces. Here, nanoparticle-supported lipid bilayers (NP-SLBs) made of 100-nm SiO2 nanoparticles and the zwitterionic lipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) are investigated as constructs for removing PAHs from contaminated sites, using benzo[a]pyrene (BaP) as an example. DMPC in the form of small unilamellar vesicles (SUVs) or DMPC-NP-SLBs with excess DMPC-SUVs to support colloidal stability, when added to saturated BaP solutions, sorb BaP in ratios of up to 10/1 to 5/1 lipid/BaP, over a 2-week period at 33 °C. This rate increases with temperature. The presence of humic acid (HA), as an analog of soil organic matter, does not affect the BaP uptake rate by DMPC-NP-SLBs and DMPC-SUVs, indicating preferential BaP sorption into the hydrophobic lipids. HA increases the zeta potential of these nanosystems, but does not disrupt their morphology, and enhances their colloidal stability. Studies with the common soil bacteria Pseudomonas aeruginosa demonstrate viability and growth using DMPC-NP-SLBs and DMPC-SUVs, with and without BaP, as their sole carbon source. Thus, NP-SLBs may be an effective method for remediation of PAHs, where the lipids provide both the method of extraction and stability for transport to the contaminant site.

  10. Mode-coupling study on the dynamics of hydrophobic hydration II: Aqueous solutions of benzene and rare gases.

    Science.gov (United States)

    Yamaguchi, T; Matsuoka, T; Koda, S

    2006-02-14

    The dynamic properties of both the solute and solvent of the aqueous solution of benzene, xenon and neon are calculated by the mode-coupling theory for molecular liquids based on the interaction-site model. The B-coefficients of the reorientational relaxation and the translational diffusion of the solvent are evaluated from their dependence on the concentration of the solute, and the reorientational relaxation time of water within the hydration shell is estimated based on the two-state model. The reorientational relaxation times of water in the bulk and within the hydration shell, that of solute, and the translational diffusion coefficients of solute and solvent, are calculated at 0-30 degrees C. The temperature dependence of these dynamic properties is in qualitative agreement with that of NMR experiment reported by Nakahara et al. (M. Nakahara, C. Wakai, Y. Yoshimoto and N. Matubayasi, J. Phys. Chem., 1996, 100, 1345-1349, ref. 36), although the agreement of the absolute values is not so good. The B-coefficients of the reorientational relaxation times for benzene, xenon and neon solution are correlated with the hydration number and the partial molar volume of the solute. The proportionality with the latter is better than that with the former. These results support the mechanism that the retardation of the mobility of water is caused by the cavity formation of the solute, as previously suggested by us (T. Yamaguchi, T. Matsuoka and S. Koda, J. Chem. Phys., 2004, 120, 7590-7601, ref. 34), rather than the conventional one that the rigid hydration structure formed around the hydrophobic solute reduces the mobility of water.

  11. Comparison of two polarity measurements of hydrophobic organic matter for the evaluation of water treatment processes: XAD resin and PRAM.

    Science.gov (United States)

    Philibert, Marc; Rosario-Ortiz, Fernando; Suffet, Mel

    2012-01-01

    Dissolved organic matter (DOM) is a mixture of thousands of organic molecules wide-ranging in molecular weight, polarity and physicochemical properties. DOM is responsible for multiple water treatment issues such as trihalomethane (THM) formation potential and membrane fouling. Two methods of evaluating the polarity of DOM are being used for water treatment application: a serial XAD resin adsorption method at acid pH and the polarity rapid assessment method (PRAM) by parallel solid phase extraction (SPE) cartridges at natural pH. These two methods have been described by their authors as able to define a hydrophobic fraction though they do so by sorption onto different types of material at different pHs. The first part of this study compared the PRAM and XAD methods and showed that the hydrophobic fractions defined by the two approaches were not correlated. This result highlighted the difficulties in defining fractions as 'hydrophobic material'. It appeared that the sorbents for XAD-8 (an acrylic polymer containing oxygen) at pH <3 and C-18 (a pure hydrocarbon polymer coating on silica particles) at neutral or pH <3 did not retain similar hydrophobic fractions. This hypothesis was verified by fluorescence spectroscopy of the effluent of the XAD-8 resin and PRAM C-18 SPE cartridge. Finally the study concentrated on the use of fluorescence and ultrafiltration methods in series with PRAM to gain more insight into the structure and characteristics of the hydrophobic DOM present in drinking water sources. This evaluation showed that the smaller molecular weight fraction of DOM (<1 kDa) had a higher percentage of hydrophobic character and that the fluorescence-defined aromatic protein fraction was the most hydrophilic.

  12. Surfactant-Enhanced Phytoremediation of Soils Contaminated with Hydrophobic Organic Contaminants: Potential and Assessment

    Institute of Scientific and Technical Information of China (English)

    GAO Yan-Zheng; LING Wan-Ting; ZHU Li-Zhong; ZHAO Bao-Wei; ZHENG Qing-Song

    2007-01-01

    Phytoremediation is becoming a cost-effective technology for the in-situ clean up of sites polluted with hydrophobic organic contaminants (HOCs). The major factors limiting phytoremediation are the mass transfer, rate of plant uptake, and microbial biodegradation of HOCs. This article discusses the potential of surfactants to enhance desorption, plant uptake, and biodegradation of HOCs in the contaminated sites. Positive effects of surfactants on phytoremediation have been recently observed in greenhouse studies. The presence of some nonionic surfactants including polyoxyethylene sorbitan monooleate (Tween 80) and polyoxyethylene(23)dodecanol (Brij35) at relatively low concentrations resulted in significant positive effects on phytoremediation for pyrene-contaminated soil. However, the anionic surfactant (sodium dodecyl sulfate, SDS) and the cationic surfactant (cetyltrimethylammonium bromide, CTMAB) were not useful because of their phytotoxicity or low efficiency for surfactant-enhanced phytoremediation (SEPR). The mechanisms of SEPR for HOC-contaminated sites were evaluated by considering experimental observations. In view of concerns about the cost effectiveness and toxicity of surfactants to plants, more research is needed to enhance the use of SEPR technology.

  13. Determining the chemical activity of hydrophobic organic compounds in soil using polymer coated vials

    Directory of Open Access Journals (Sweden)

    Jönsson Jan-Åke

    2008-05-01

    Full Text Available Abstract Background In soils contaminated by hydrophobic organic compounds, the concentrations are less indicative of potential exposure and distribution than are the associated chemical activities, fugacities and freely dissolved concentrations. The latter can be measured by diffusive sampling into thin layers of polymer, as in, for example, solid phase micro-extraction. Such measurements require equilibrium partitioning of analytes into the polymer while ensuring that the sample is not depleted. We introduce the validation of these requirements based on parallel sampling into polymer layers of different thicknesses. Results Equilibrium sampling devices were made by coating glass vials internally with 3–12 μm thick layers of polydimethylsiloxane (PDMS. These were filled with slurries of a polluted soil and gently agitated for 5 days. The concentrations of 7 polycyclic aromatic hydrocarbons (PAHs in the PDMS were measured. Validation confirmed fulfilment of the equilibrium sampling requirements and high measurement precision. Finally, chemical activities of the PAHs in the soil were determined from their concentrations and activity coefficients in the PDMS. Conclusion PAHs' thermodynamic activities in a soil test material were determined via a method of uptake into PDMS. This can be used to assess chemical exposure and predict diffusion and partitioning processes.

  14. Sorption of hydrophobic organic compounds to a diverse suite of carbonaceous materials with emphasis on biochar.

    Science.gov (United States)

    Kupryianchyk, Darya; Hale, Sarah; Zimmerman, Andrew R; Harvey, Omar; Rutherford, David; Abiven, Samuel; Knicker, Heike; Schmidt, Hans-Peter; Rumpel, Cornelia; Cornelissen, Gerard

    2016-02-01

    Carbonaceous materials like biochars are increasingly recognized as effective sorbent materials for sequestering organic pollutants. Here, we study sorption behavior of two common hydrophobic organic contaminants 2,2',5,5'-tetrachlorobiphenyl (CB52) and phenanthrene (PHE), on biochars and other carbonaceous materials (CM) produced at a wide range of conditions and temperatures from various feedstocks. The primary aim was to establish structure-reactivity relationships responsible for the observed variation in CM and biochar sorption characteristics. CM were characterized for their elemental composition, surface area, pore size distribution, aromaticity and thermal stability. Freundlich sorption coefficients for CB52 and PHE (i.e. LogK(F,CB52) and K(F,PHE), respectively) to CM showed a variation of two to three orders of magnitude, with LogK(F,CB52) ranging from 5.12 ± 0.38 to 8.01 ± 0.18 and LogK(F,PHE) from 5.18 ± 0.09 to 7.42 ± 1.09. The highest LogK(F) values were observed for the activated CM, however, non-activated biochars produced at high temperatures (>700 °C) sorbed almost as strongly (within 0.2-0.5 Log units) as the activated ones. Sorption coefficients significantly increased with pyrolysis temperature, CM surface area and pore volume, aromaticity, and thermal stability, and decreased with H/C, O/C, (O + N)/C content. The results of our study contribute to the understanding of processes underlying HOC sorption to CM and explore the potential of CM as engineered sorbents for environmental applications.

  15. Organ preservation solutions : clinical and pharmaceutical aspects

    NARCIS (Netherlands)

    Leuvenink, Henri G. D.; Ploeg, Rutger J.

    2009-01-01

    Systematic research has led to continuing improvements in the solutions and techniques of preserving donated hearts. The persistent shortage of donors means that organs of lower quality are increasingly being accepted and we are turning more and more to machine perfusion of donated hearts.

  16. Understanding the fouling of algogenic organic matter in microfiltration using membrane-foulant interaction energy analysis: effects of organic hydrophobicity.

    Science.gov (United States)

    Huang, Weiwei; Chu, Huaqiang; Dong, Bingzhi

    2014-10-01

    Fouling caused by algogenic organic matter (AOM) in membrane filtration is a critical problem in algae-rich waters, and understanding fouling mechanisms, particularly by identifying the predominant membrane foulants, could have significant effects on algal fouling prediction and pretreatment. In this work, the fouling behavior of Aphanizomenon flos-aquae (APF)- and Anabaena flos-aquae (ANF)-AOM fractions was analyzed using the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. The results show that the interfacial energy of membranes and foulants could be used for AOM membrane fouling analysis. The attractive energy was highest between the membrane and the neutral hydrophilic fractions (N-HPI) on clean membrane surfaces, followed by the energy associated with the hydrophobic fractions (HPO) and the transphilic fractions (TPI) in both of the AOMs; on the other hand, the negatively charged hydrophilic organics (C-HPI) in the APF-AOM suffered from repulsive interactions when nearing the membrane surface, which was consistent with their initial filtration flux. After the formation of an initial fouling layer on the membrane surface, membrane fouling was controlled mainly by the cohesion free energy between the approaching foulants and the foulants on the fouled membranes. In addition, it was observed that the interfacial energy between foulants was the dominant factor controlling membrane fouling in AOM filtration. Finally, the interfacial energies between the N-HPI fractions had the greatest effect on both APF-AOM and ANF-AOM membrane fouling. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Adsorption and nanowear properties of bovine submaxillary mucin films on solid surfaces: Influence of solution pH and substrate hydrophobicity

    DEFF Research Database (Denmark)

    Sotres, Javier; Madsen, Jan Busk; Arnebrant, Thomas;

    2014-01-01

    The adsorption and mechanical stability of bovine submaxillary mucins (BSM) films at solid-liquid interfaces were studied with respect to both substrate hydrophobicity and solution pH. Dynamic light scattering revealed a single peak distribution in neutral aqueous solution (pH 7.4) and a small...... fraction with enhanced aggregation was observed in acidic solution (pH 3.8). Both substrate hydrophobicity and solution pH were found to affect the spontaneous adsorption of BSM onto solid surfaces; BSM adsorbed more onto hydrophobic surfaces than hydrophilic ones, and adsorbed more at pH 3.8 than at pH 7.......4. Thus, the highest "dry" adsorbed mass was observed for hydrophobic surfaces in pH 3.8 solution. However, a highest "wet" adsorbed mass, i.e. which includes the solvent coupled to the film, was observed for hydrophobic surfaces at pH 7.4. The mechanical stability of the films was studied...

  18. Quantitative evaluation of XAD-8 and XAD-4 resins used in tandem for removing organic solutes from water

    Science.gov (United States)

    Malcolm, R.L.; MacCarthy, P.

    1992-01-01

    The combined XAD-8 and XAD-4 resin procedure for the isolation of dissolved organic solutes from water was found to isolate 85% or more of the organic solutes from Lake Skjervatjern in Norway. Approximately 65% of the dissolved organic carbon (DOC) was first removed on XAD-8 resin, and then an additional 20% of the DOC was removed on XAD-4 resin. Approximately 15% of the DOC solutes (primarily hydrophilic neutrals) were not sorbed or concentrated by the procedure. Of the 65% of the solutes removed on XAD-8 resin, 40% were fulvic acids, 16% were humic acids, and 9% were hydrophobic neutrals. Approximately 20% of the hydrophilic solutes that pass through the XAD-8 resin were sorbed solutes on the second resin, XAD-4 (i.e., they were hydrophobic relative to the XAD-4 resin). The fraction sorbed on XAD-4 resin was called XAD-4 acids because it represented approximately 85-90% of the hydrophilic XAD-8 acid fraction according to the original XAD-8 fractionation procedure. The recovery of hydrophobic acids (fulvic acids and humic acids) and the hydrophobic neutral fraction from XAD-8 resin was essentially quantitative at 96%, 98%, and 86%, respectively. The recovery of XAD-4 acids from the XAD-4 resin was only about 50%. The exact reason for this moderately low recovery is unknown, but could result from ??-?? bonding between these organic solutes and the aromatic matrix of XAD-4. The hydrophobic/hydrophilic solute separation on XAD-8 resin for water from background Side A and Side B of the lake was almost identical at 65 and 67%, respectively. This result suggested that both sides of the lake are similar in organic chemical composition even though the DOC variation from side to side is 20%.

  19. Removal of Endotoxin from Human Serum Albumin Solutions by Hydrophobic and Cationic Charged Membrane

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A novel matrix of macropore cellulose membrane was prepared by chemical graft, and immobilized the cationic charged groups as affinity ligands. The prepared membrane can be used for the removal of endotoxin from human serum albumin (HSA) solutions. With a cartridge of 20 sheets affinity membrane of 47 mm diameter, the endotoxin level in HSA solution can be reduced to 0.027 eu/mL. Recovery of HSA was over 95%.

  20. Biochemical methane potential of fractions of organic matter extracted from a municipal solid waste leachate: Impact of their hydrophobic character.

    Science.gov (United States)

    Baccot, Camille; Pallier, Virginie; Feuillade-Cathalifaud, Geneviève

    2016-12-05

    Many data on anaerobic digestion (AD) and co-digestion of municipal solid waste leachate (MSWL) are already available in literature. They mainly deal with its performances to decrease the chemical oxygen demand (COD) of MSWL and no information is given on the impact of the specific characteristics of the dissolved organic matter (DOM) in leachate on these performances. DOM in leachate evolves towards more aromatic and hydrophobic compounds during landfilling with increasing specific ultra-violet absorbance index (SUVA) and hydrophobic character. However, according to the humification stages, this DOM would not present the same aptitude for AD. This research thus focused on (i) optimizing a biochemical methane potential (BMP) test applied to MSWL by using the Taguchi method and (ii) evaluating the impact of the hydrophobic character of the DOM in leachate on the BMP of MSWL to finally define the humification degree more suitable for AD. Hydrophobic-like (HPO(∗)) and transphilic-like (TPH(∗)) compounds extracted from leachate by a fractionation protocol were tested because of their high content in MSWL during acetogenesis and methanogenesis steps. After 275days of AD, the content in hydrophobic compounds and the SUVA indexes increased in the digestates. Moreover, even if the biogas and methane productions were not significantly different during the whole tests (4072±350mLgDOC(-1) and 2370±95mLgDOC(-1) respectively), the volume of biogas produced directly correlated with the TPH(∗) fraction content in the initial digestates. On the contrary, the methane percentage in biogas was anti-correlated with the hydrophilic-like compounds content. The hydrophobic-like molecules seem thus not to be directly involved in the methanogenic step, however they promote the increase of the methane percent in the biogas.

  1. Stabilization by hydrophobic protection as a molecular mechanism for organic carbon sequestration in maize-amended rice paddy soils.

    Science.gov (United States)

    Song, X Y; Spaccini, R; Pan, G; Piccolo, A

    2013-08-01

    The hydrophobic components of soil organic matter (SOM) are reckoned to play an important role in the stabilization of soil organic carbon (SOC). The contribution of hydrophobic substances to SOC sequestration was evaluated in four different paddy soils in the South of China, following a 6-month incubation experiment with maize straw amendments. Soil samples included: a well developed paddy soil (TP) derived from clayey lacustrine deposits in the Tai Lake plain of Jiangsu; an acid clayey paddy soil (RP) derived from red earth in the rolling red soil area of Jiangxi; a weakly developed neutral paddy soil (PP) formed on Jurassic purple shale from Chongq; and a calcic Fluvisol (MS) derived from riverine sediments from a wetland along the Yangtze valley of Anhui, China. The SOC molecular composition after 30 and 180 days of incubation, was determined by off-line thermochemolysis followed by gas chromatography-mass spectrometry analysis. Lignin, lipids and carbohydrates were the predominant thermochemolysis products released from the treated soils. A selective preservation of hydrophobic OM, including lignin and lipids, was shown in maize amended soils with prolonged incubation. The decomposition of lignin and lipids was significantly slower in the TP and RP soils characterized by a larger content of extractable iron oxyhydrates (Fed) and lower pH. The overall increase in hydrophobic substances in maize incubated samples was correlated, positively, with total content of clay and Fed, and, negatively, with soil pH. Moreover, yields of both lignin and lipid components showed a significant relationship with SOC increase after incubation. These findings showed that the larger the lipid and lignin content of SOM, the greater was the stability of SOC, thereby suggesting that OM hydrophobic components may have an essential role in controlling the processes of OC sequestration in paddy soils of South China.

  2. Quantifying the effect of medium composition on the diffusive mass transfer of hydrophobic organic chemicals through unstirred boundary layers

    DEFF Research Database (Denmark)

    Mayer, Philipp; Karlson, U.; Christensen, P.S.

    2005-01-01

    Unstirred boundary layers (UBLs) often act as a bottleneck for the diffusive transport of hydrophobic organic compounds (HOCs) in the environment. Therefore, a microscale technique was developed for quantifying mass transfer through a 100-μm thin UBL, with the medium composition of the UBL...... as the controllable factor. The model compound fluoranthene had to (1) partition from a contaminated silicone disk (source) into the medium, (2) then diffuse through 100 μm of medium (UBL), and finally (3) partition into a clean silicone layer (sink). The diffusive mass transfer from source to sink was monitored over...... of magnitude. These results demonstrate that medium constituents, which normally are believed to bind hydrophobic organic chemicals, actually can enhance the diffusive mass transfer of HOCs in the vicinity of a diffusion source (e.g., contaminated soil particles). The technique can be used to evaluate...

  3. The impact of framework organic functional groups on the hydrophobicity and overall stability of mesoporous silica materials

    Energy Technology Data Exchange (ETDEWEB)

    Smeulders, Geert, E-mail: geert.smeulders@ua.ac.be [University of Antwerpen (Ukraine), Laboratory of Adsorption and Catalysis, Universiteitsplein 1, 2610 Wilrijk (Belgium); Meynen, Vera [University of Antwerpen (Ukraine), Laboratory of Adsorption and Catalysis, Universiteitsplein 1, 2610 Wilrijk (Belgium); Silvestre-Albero, Ana [Universidad de Alicante, Laboratorio de Materiales Avanzados, Apartado 99, 03080 Alicante (Spain); Houthoofd, Kristof [KULeuven, Centre for Surface Chemistry and Catalysis, Kasteelpark Arenberg 23, 3001 Heverlee (Belgium); Mertens, Myrjam [Flemish Institute for Technological Research (VITO N.V.), Boeretang 200, 2400 Mol (Belgium); Silvestre-Albero, Joaquin [Universidad de Alicante, Laboratorio de Materiales Avanzados, Apartado 99, 03080 Alicante (Spain); Martens, Johan A. [KULeuven, Centre for Surface Chemistry and Catalysis, Kasteelpark Arenberg 23, 3001 Heverlee (Belgium); Cool, Pegie [University of Antwerpen (Ukraine), Laboratory of Adsorption and Catalysis, Universiteitsplein 1, 2610 Wilrijk (Belgium)

    2012-02-15

    Graphical abstract: The stability (hydrothermal, mechanical and chemical) of PMOs is studied in a systematic way and ranks them between classic and other hybrid mesoporous silica materials. Highlights: Black-Right-Pointing-Pointer The stability (hydrothermal, mechanical and chemical) of PMOs is studied. Black-Right-Pointing-Pointer Compared stability of PMOs with classic and other hybrid mesoporous silica materials. Black-Right-Pointing-Pointer Immersion calorimetry to study the effect of hydrophobicity. Black-Right-Pointing-Pointer PMOs show superior stability. - Abstract: The hydrothermal, mechanical and chemical stability of various mesoporous materials have been studied in detail, using X-ray diffraction and nitrogen sorption. Pure siliceous nanoporous powders (MCM-41 and SBA-15) are evaluated against their hybrid counterparts; namely 2 types of periodic mesoporous organosilicas (benzene and ethane bridged PMOs) and an organosilane grafted MCM-41 material. In primary tests, the stability of the hybrid materials is found to be superior compared to that of the pure siliceous ones. The stability of the materials was correlated to their hydrophobicity via immersion calorimetry, applied for the first time in this context. Based on these results, a clear correlation between the hydrophobicity of a material and its stability has been revealed. In addition, with {sup 29}Si-MAS-NMR and vacuum experiments, the mechanism of the structural deterioration in the three different stability treatments could be unambiguously identified as the hydrolyzation of the siloxane bonds. The homogeneity of the hydrophobic groups throughout the entire network was found to be of great importance, irrespective of the hydrophobic nature at the surface as determined by calorimetric measurements. The results reveal that the most stable material can withstand (a) a pressure of 740 MPa during 5 min, (b) a 2 h stirring in a 2 M NaOH solution and (c) a 3 day steaming treatment at 393 K.

  4. PLATINUM: a web tool for analysis of hydrophobic/hydrophilic organization of biomolecular complexes.

    Science.gov (United States)

    Pyrkov, Timothy V; Chugunov, Anton O; Krylov, Nikolay A; Nolde, Dmitry E; Efremov, Roman G

    2009-05-01

    The PLATINUM (Protein-Ligand ATtractions Investigation NUMerically) web service is designed for analysis and visualization of hydrophobic/hydrophilic properties of biomolecules supplied as 3D-structures. Furthermore, PLATINUM provides a number of tools for quantitative characterization of the hydrophobic/hydrophilic match in biomolecular complexes e.g. in docking poses. These complement standard scoring functions. The calculations are based on the concept of empirical Molecular Hydrophobicity Potential (MHP). The PLATINUM web tool as well as detailed documentation and tutorial are available free of charge for academic users at http://model.nmr.ru/platinum/. PLATINUM requires Java 5 or higher and Adobe Flash Player 9. Supplementary data are available at Bioinformatics online.

  5. Determination of solute organic concentration in contaminated soils using a chemical-equilibrium soil column system

    DEFF Research Database (Denmark)

    Gamst, Jesper; Kjeldsen, Peter; Christensen, Thomas Højlund

    2007-01-01

    Groundwater risk assessment of contaminated soils implies determination of the solute concentration leaching out of the soil. Determination based on estimation techniques or simple experimental batch approach has proven inadequate. Two chemical equilibrium soil column leaching tests...... for determination of solute concentration in a contaminated soil were developed; (1) a chemical Equilibrium and Recirculation column test for Volatile organic chemicals (ER-V) and (2) a chemical Equilibrium and Recirculation column test for Hydrophobic organic chemicals (ER-H). The two test systems were evaluated...... to measure solute phase concentration of PAHs in contaminated soils. Overall a reliable and reproducable system for determining solute concentration of a wide range of organic compounds in contaminated soils has been developed....

  6. Biotoxicity and bioavailability of hydrophobic organic compounds solubilized in nonionic surfactant micelle phase and cloud point system.

    Science.gov (United States)

    Pan, Tao; Liu, Chunyan; Zeng, Xinying; Xin, Qiao; Xu, Meiying; Deng, Yangwu; Dong, Wei

    2017-06-01

    A recent work has shown that hydrophobic organic compounds solubilized in the micelle phase of some nonionic surfactants present substrate toxicity to microorganisms with increasing bioavailability. However, in cloud point systems, biotoxicity is prevented, because the compounds are solubilized into a coacervate phase, thereby leaving a fraction of compounds with cells in a dilute phase. This study extends the understanding of the relationship between substrate toxicity and bioavailability of hydrophobic organic compounds solubilized in nonionic surfactant micelle phase and cloud point system. Biotoxicity experiments were conducted with naphthalene and phenanthrene in the presence of mixed nonionic surfactants Brij30 and TMN-3, which formed a micelle phase or cloud point system at different concentrations. Saccharomyces cerevisiae, unable to degrade these compounds, was used for the biotoxicity experiments. Glucose in the cloud point system was consumed faster than in the nonionic surfactant micelle phase, indicating that the solubilized compounds had increased toxicity to cells in the nonionic surfactant micelle phase. The results were verified by subsequent biodegradation experiments. The compounds were degraded faster by PAH-degrading bacterium in the cloud point system than in the micelle phase. All these results showed that biotoxicity of the hydrophobic organic compounds increases with bioavailability in the surfactant micelle phase but remains at a low level in the cloud point system. These results provide a guideline for the application of cloud point systems as novel media for microbial transformation or biodegradation.

  7. Organ shortage crisis: problems and possible solutions.

    Science.gov (United States)

    Abouna, G M

    2008-01-01

    The demand for organ transplantation has rapidly increased all over the world during the past decade due to the increased incidence of vital organ failure, the rising success and greater improvement in posttransplant outcome. However, the unavailability of adequate organs for transplantation to meet the existing demand has resulted in major organ shortage crises. As a result there has been a major increase in the number of patients on transplant waiting lists as well as in the number of patients dying while on the waiting list. In the United States, for example, the number of patients on the waiting list in the year 2006 had risen to over 95,000, while the number of patient deaths was over 6,300. This organ shortage crisis has deprived thousands of patients of a new and better quality of life and has caused a substantial increase in the cost of alternative medical care such as dialysis. There are several procedures and pathways which have been shown to provide practical and effective solutions to this crisis. These include implementation of appropriate educational programs for the public and hospital staff regarding the need and benefits of organ donation, the appropriate utilization of marginal (extended criteria donors), acceptance of paired organ donation, the acceptance of the concept of "presumed consent," implementation of a system of "rewarded gifting" for the family of the diseased donor and also for the living donor, developing an altruistic system of donation from a living donor to an unknown recipient, and accepting the concept of a controlled system of financial payment for the donor. As is outlined in this presentation, we strongly believe that the implementation of these pathways for obtaining organs from the living and the dead donors, with appropriate consideration of the ethical, religious and social criteria of the society, the organ shortage crisis will be eliminated and many lives will be saved through the process of organ donation and

  8. Networks of polysaccharides with hydrophilic and hydrophobic characteristics in the presence of co-solute.

    Science.gov (United States)

    Almrhag, Omar; George, Paul; Bannikova, Anna; Katopo, Lita; Kasapis, Stefan

    2012-01-01

    The present investigation deals with the changing network morphology of agarose and high methoxy pectin when mixed with polydextrose as co-solute at concentrations varying up to high level of solids. Thermomechanical analysis and micro-imaging were performed using small deformation dynamic oscillation in shear, modulated differential scanning calorimetry and environment scanning electron microscopy. Fourier transform infrared spectroscopy and wide angle X-ray diffraction were practised to examine the nature of interactions between polymer and co-solute, and the extent of amorphicity of preparations. We observed a decline in the mechanical strength of aqueous agarose preparations upon addition of high levels of polydextrose, which should be attributed to reduced enthalpic content of the coil-to-helix transition of the polysaccharide network. Glass transition phenomena were observed at subzero temperatures in condensed preparations, hence further arguing for the formation of a lightly cross-linked agarose network with changing solvent quality. High levels of co-solute induce formation of weak pectin gels at elevated temperatures (even at 95°C), which with lowering temperature exhibit increasing strength. This results in the formation of rubbery pectin gels at ambient temperature, which upon controlled cooling to subzero temperatures convert to a clear glass earlier than the agarose counterparts.

  9. Role of long- and short-range hydrophobic, hydrophilic and charged residues contact network in protein’s structural organization

    Directory of Open Access Journals (Sweden)

    Sengupta Dhriti

    2012-06-01

    Full Text Available Abstract Background The three-dimensional structure of a protein can be described as a graph where nodes represent residues and the strength of non-covalent interactions between them are edges. These protein contact networks can be separated into long and short-range interactions networks depending on the positions of amino acids in primary structure. Long-range interactions play a distinct role in determining the tertiary structure of a protein while short-range interactions could largely contribute to the secondary structure formations. In addition, physico chemical properties and the linear arrangement of amino acids of the primary structure of a protein determines its three dimensional structure. Here, we present an extensive analysis of protein contact subnetworks based on the London van der Waals interactions of amino acids at different length scales. We further subdivided those networks in hydrophobic, hydrophilic and charged residues networks and have tried to correlate their influence in the overall topology and organization of a protein. Results The largest connected component (LCC of long (LRN-, short (SRN- and all-range (ARN networks within proteins exhibit a transition behaviour when plotted against different interaction strengths of edges among amino acid nodes. While short-range networks having chain like structures exhibit highly cooperative transition; long- and all-range networks, which are more similar to each other, have non-chain like structures and show less cooperativity. Further, the hydrophobic residues subnetworks in long- and all-range networks have similar transition behaviours with all residues all-range networks, but the hydrophilic and charged residues networks don’t. While the nature of transitions of LCC’s sizes is same in SRNs for thermophiles and mesophiles, there exists a clear difference in LRNs. The presence of larger size of interconnected long-range interactions in thermophiles than mesophiles, even at

  10. Assessment of PDMS-water partition coefficients: implications for passive environmental sampling of hydrophobic organic compounds

    Science.gov (United States)

    DiFilippo, Erica L.; Eganhouse, Robert P.

    2010-01-01

    Solid-phase microextraction (SPME) has shown potential as an in situ passive-sampling technique in aquatic environments. The reliability of this method depends upon accurate determination of the partition coefficient between the fiber coating and water (Kf). For some hydrophobic organic compounds (HOCs), Kf values spanning 4 orders of magnitude have been reported for polydimethylsiloxane (PDMS) and water. However, 24% of the published data examined in this review did not pass the criterion for negligible depletion, resulting in questionable Kf values. The range in reported Kf is reduced to just over 2 orders of magnitude for some polychlorinated biphenyls (PCBs) when these questionable values are removed. Other factors that could account for the range in reported Kf, such as fiber-coating thickness and fiber manufacturer, were evaluated and found to be insignificant. In addition to accurate measurement of Kf, an understanding of the impact of environmental variables, such as temperature and ionic strength, on partitioning is essential for application of laboratory-measured Kf values to field samples. To date, few studies have measured Kf for HOCs at conditions other than at 20 degrees or 25 degrees C in distilled water. The available data indicate measurable variations in Kf at different temperatures and different ionic strengths. Therefore, if the appropriate environmental variables are not taken into account, significant error will be introduced into calculated aqueous concentrations using this passive sampling technique. A multiparameter linear solvation energy relationship (LSER) was developed to estimate log Kf in distilled water at 25 degrees C based on published physicochemical parameters. This method provided a good correlation (R2 = 0.94) between measured and predicted log Kf values for several compound classes. Thus, an LSER approach may offer a reliable means of predicting log Kf for HOCs whose experimental log Kf values are presently unavailable. Future

  11. Comparison of PoraPak Rxn RP and XAD-2 adsorbents for monitoring dissolved hydrophobic organic contaminants.

    Science.gov (United States)

    Omara, Mark; Holsen, Thomas M; Xia, Xiaoyan; Pagano, James J; Crimmins, Bernard S; Hopke, Philip K

    2014-11-01

    Accurate determination of the levels of dissolved hydrophobic organic contaminants (HOCs) is an important step in estimating the dynamics of their inputs and losses in aqueous systems. This study explores an alternative method for efficiently sampling dissolved HOCs while mitigating a number of sampling artifacts associated with traditional methods. The adsorption characteristics of a new polymeric resin, PoraPak Rxn RP (PPR), were assessed using sorption isotherm experiments and fixed bed adsorption studies. The adsorption capacities and breakthrough times for four model contaminants (phenol, p-nitrophenol, naphthalene, and 2,4,6-tribromophenol) were proportional to the contaminant's hydrophobicity. The ability of PPR to isolate dissolved polychlorinated biphenyls (PCBs) in real samples was compared with that of XAD-2, a well-known macroporous polymer that suffers from high background contamination. The results indicated that the PPR resin can be effectively used for monitoring HOCs, with low ∑PCB levels in blanks, decreasing solvent use, and reducing extraction times.

  12. Measurement of low amounts of amorphous content in hydrophobic active pharmaceutical ingredients with dynamic organic vapor sorption.

    Science.gov (United States)

    Müller, Thorsten; Schiewe, Jörg; Smal, Rüdiger; Weiler, Claudius; Wolkenhauer, Markus; Steckel, Hartwig

    2015-05-01

    Today, a variety of devices for dry powder inhalers (DPIs) is available and many different formulations for optimized deposition in the lung are developed. However, during the production of powder inhalers, processing steps may induce changes to both, the carrier and active pharmaceutical ingredients (APIs). It is well known that standard pharmaceutical operations may lead to structural changes, crystal defects and amorphous regions. Especially operations such as milling, blending and even sieving generate these effects. These disorders may induce re-crystallization and particle size changes post-production which have a huge influence on drug delivery and product stability. In this study, pilot tests with a polar solvent (water) and hydrophilic drug (Salbutamol sulfate) were performed to receive a first impression on further possible implementation of hydrophobic samples with organic solvents. Thereafter, a reliable method for the accurate detection of low amounts of amorphous content is described up to a limit of quantification (LOQ) of 0.5% for a hydrophobic model API (Ciclesonide). The organic vapor sorption method which is a gravimetric method quantifies exactly these low amounts of amorphous content in the hydrophobic powder once the suitable solvent (isopropanol), the correct p/p0 value (0.1) and the exact temperature (25°C) have been found. Afterward it was possible to quantitate low amorphous amounts in jet-milled powders (0.5-17.0%). In summary, the data of the study led to a clearer understanding in what quantity amorphous parts were generated in single production steps and how variable these parts behave to fully crystalline material. Nevertheless it showed how difficult it was to re-crystallize hydrophobic material with water vapor over a short period. For the individual samples it was possible to determine the single humidity at which the material starts to re-crystallize, the behavior against different nonpolar solvents and the calculation of the

  13. Hydrophobic Forces in Flotation

    OpenAIRE

    Pazhianur, Rajesh R

    1999-01-01

    An atomic force microscope (AFM) has been used to conduct force measurements to better understand the role of hydrophobic forces in flotation. The force measurements were conducted between a flat mineral substrate and a hydrophobic glass sphere in aqueous solutions. It is assumed that the hydrophobic glass sphere may simulate the behavior of air bubbles during flotation. The results may provide information relevant to the bubble-particle interactions occurring during flotation. The glass ...

  14. Removal of Organic Dyes from Aqueous Solutions with Surfactant-Modified Magnetic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Wybieralska Katarzyna

    2014-06-01

    Full Text Available The paper presents the results of studies on the possibility of using magnetic nanoparticles modified with selected hydrophobic surfactants for model post-production water purification. Colloidal solutions of iron hydroxide (III and iron oxide (II and III were obtained and their particles were subjected to surface modification using surfactants. Thus obtained magnetic fluids were used as active agents in the process of removing selected organic dyes from their aqueous solutions. The effectiveness of the modified compounds was analysed using spectrophotometric methods. It has been shown that the effectiveness of the process depends on the type of surfactant used to modify selected magnetic nanoparticles.

  15. The chemical modification of  -chymotrypsin with both hydrophobic and hydrophilic compounds stabilizes the enzyme against denaturation in water-organic media

    National Research Council Canada - National Science Library

    Vinogradov, A.A; Kudryashova, E.V; Grinberg, V.Ya; Grinberg, N.V; Burova, T.V; Levashov, A.V

    2001-01-01

    We considered [alpha]-chymotrypsin (CT) in homogeneous water-organic media as a model system to examine the influence of enzyme chemical modification with hydrophilic and hydrophobic substances on its stability, activity and structure...

  16. Efficient "on-the-fly" calculation of Raman spectra from \\textit{ab-initio} molecular dynamics: Application to hydrophobic/hydrophilic solutes in bulk water

    CERN Document Server

    Partovi-Azar, Pouya

    2015-01-01

    We present a computational method to accurately calculate Raman spectra from first principles with an at least one order of magnitude higher efficiency. This scheme thus allows to routinely calculate finite-temperature Raman spectra "on-the-fly" by means of \\textit{ab-initio} molecular dynamics simulations. To demonstrate the predictive power of this approach we investigate the effect of hydrophobic and hydrophilic solutes in water solution on the infrared and Raman spectra.

  17. Evolution and accumulation of organic foulants on hydrophobic and hydrophilic membrane surfaces in a submerged membrane bioreactor

    KAUST Repository

    Matar, Gerald

    2015-09-07

    Membrane surface modification is attracting more attention to mitigate biofouling in membrane bioreactors (MBRs). Five membranes differing in chemistry and hydrophobic/hydrophilic potential were run in parallel in a lab-scale MBR under the same conditions. Membranes were sampled after 1, 10, 20 and 30 days of MBR operation with synthetic wastewater. Subsequently, accumulated organic foulants were characterised using several chemical analytical tools. Results showed similar development of organic foulants with time, illustrating that membrane surface chemistry did not affect the selection of specific organic foulants. Multivariate analysis showed that biofilm samples clustered according to the day of sampling. The composition of organic foulants shifted from protein-like substances towards humics and polysaccharides-like substances. We propose that to control biofouling in MBRs, one should focus less on the membrane surface chemistry.

  18. Synthesis and toxicity evaluation of hydrophobic ionic liquids for volatile organic compounds biodegradation in a two-phase partitioning bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Castillo, Alfredo Santiago [Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7 (France); Université européenne de Bretagne (France); Guihéneuf, Solène, E-mail: solene.guiheneuf@wanadoo.fr [Université européenne de Bretagne, Université de Rennes 1, Sciences Chimiques de Rennes, UMR, CNRS 6226, Groupe Ingénierie Chimique & Molécules Pour le Vivant (ICMV), Bât. 10A, Campus de Beaulieu, Avenue du Général Leclerc, CS 74205, 35042 Rennes cedex (France); Le Guével, Rémy [Plate-forme ImPACcell Structure Fédérative de Recherche BIOSIT Université de Rennes 1, Bat. 8, Campus de Villejean, 2 Avenue du Pr. Leon Bernard, CS 34317, 35043 Rennes Cedex (France); Biard, Pierre-François [Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7 (France); Université européenne de Bretagne (France); and others

    2016-04-15

    Highlights: • Description of a VOC depollution system suitable with industrial processes, TPPB. • Novel association of TPPB and hydrophobic ionic liquids. • Synthesis of several hydrophobic ionic liquids designed to fit desired properties. • Toxicity evaluation of these ILs towards cells, animals and bacteria. - Abstract: Synthesis of several hydrophobic ionic liquids (ILs), which might be selected as good candidates for degradation of hydrophobic volatile organic compounds in a two-phase partitioning bioreactor (TPPB), were carried out. Several bioassays were also realized, such as toxicity evaluation on activated sludge and zebrafish, cytotoxicity, fluoride release in aqueous phase and biodegradability in order to verify their possible effects in case of discharge in the aquatic environment and/or human contact during industrial manipulation. The synthesized compounds consist of alkylimidazoliums, functionalized imidazoliums, isoqinoliniums, triazoliums, sulfoniums, pyrrolidiniums and morpholiniums and various counter-ions such as: PF{sub 6}{sup −}, NTf{sub 2}{sup −} and NfO{sup −}. Toxicity evaluation on activated sludge of each compound (5% v/v of IL) was assessed by using a glucose uptake inhibition test. Toxicity against zebrafish and cytotoxicity were evaluated by the ImPACCell platform of Rennes (France). Fluoride release in water was estimated by regular measurements using ion chromatography equipment. IL biodegradability was determined by measuring BOD{sub 28} of aqueous samples (compound concentration,1 mM). All ILs tested were not biodegradable; while some of them were toxic toward activated sludge. Isoquinolinium ILs were toxic to human cancerous cell lines. Nevertheless no toxicity was found against zebrafish Danio rerio. Only one IL released fluoride after long-time agitation.

  19. Removal of methylene blue from its aqueous solution by froth flotation: hydrophobic silica nanoparticle as a collector

    Science.gov (United States)

    Hu, Nan; Liu, Wei; Ding, Linlin; Wu, Zhaoliang; Yin, Hao; Huang, Di; Li, Hongzhen; Jin, Lixue; Zheng, Huijie

    2017-02-01

    Dye pollution has been a severe problem faced by worldwide environmentalists. The use of nanoparticles as adsorbents has attracted widespread interests for effectively removing dyes, while the separation of them from an aqueous solution is a difficult and important subject. For achieving the simultaneous removal of methylene blue (MB) and nanoadsorbents, this work utilized a commercial hydrophobic silica nanoparticle (SNP) (200.0 ± 10.0 nm in average particle size) as a collector and then developed a novel froth flotation technology without using any surfactants. Under the suitable conditions of anhydrous ethanol dosage of 8 mL, pH of 9.0, SNP concentration of 600 mg/L, and flotation column height of 600 mm, the removal efficiencies of MB and SNPs and the volume ratio reached 91.1 ± 4.6%, 93.9 ± 4.7%, and 10.5 ± 0.5, respectively. Subsequently, the recovered MB-adsorbed SNPs in the foamate were separated by free setting due to their high concentration and massive agglomeration. After free setting, MB could be effectively separated from the recovered MB-adsorbed SNPs by using ethanol at pH 2.0 and repeating five cycles of washing-centrifugation. Additionally, the regenerated SNPs could be reused for removing MB up to five times. Overall, this work had a significant meaning for the treatment of dye-contaminated wastewaters.

  20. 疏水缔合聚合物的合成及溶液性质研究%Synthesis and Solution Properties of Hydrophobic Associating Polymers

    Institute of Scientific and Technical Information of China (English)

    任鲲; 姜桂元; 徐春明; 林梅钦

    2005-01-01

    Acrylamide/2-acrylamido alkane sulfonic acid hydrophobic associating copolymers were synthesized by micellar copolymerization. Effects of hydrophobe content, polymer concentration, salinity and surfactant on rheological behavior of copolymers were investigated and the conformation of polymers in solution was studied by means of environmental scanning electronic microscopy and dynamic light scattering. The experimental results showed that in the dilute regime the hydrophobic parts could interact intramolecularly, while in the regime where the polymer concentration was higher than the critical association concentration, intermolecular hydrophobic association became predominant. Within the limit of the solubility, the critical association concentration of the polymer decreased with the increase of the salinity. The experimental results of the solution conformation indicated the presence of the three-dimensional network structure in deionized water and the size of the mesh in the network varied with the polymer concentration. In NaCl solution, above the critical association concentration, an increase in polymer concentration enhanced the intermolecular association and also enlarged the hydrodynamic radius. It would result in the improvement of the thickening power of polymers.

  1. Adsorptive removal of hydrophobic organic compounds by carbonaceous adsorbents: a comparative study of waste-polymer-based, coal-based activated carbon, and carbon nanotubes.

    Science.gov (United States)

    Lian, Fei; Chang, Chun; Du, Yang; Zhu, Lingyan; Xing, Baoshan; Liu, Chang

    2012-01-01

    Adsorption of the hydrophobic organic compounds (HOCs) trichloroethylene (TCE), 1,3-dichlorobenzene (DCB), 1,3-dinitrobenzene (DNB) and gamma-hexachlorocyclohexane (HCH) on five different carbonaceous materials was compared. The adsorbents included three polymer-based activated carbons, one coal-based activated carbon (F400) and multiwalled carbon nanotubes (MWNT). The polymer-based activated carbons were prepared using KOH activation from waste polymers: polyvinyl chloride (PVC), polyethyleneterephthalate (PET) and tire rubber (TR). Compared with F400 and MWNT, activated carbons derived from PVC and PET exhibited fast adsorption kinetics and high adsorption capacity toward the HOCs, attributed to their extremely large hydrophobic surface area (2700 m2/g) and highly mesoporous structures. Adsorption of small-sized TCE was stronger on the tire-rubber-based carbon and F400 resulting from the pore-filling effect. In contrast, due to the molecular sieving effect, their adsorption on HCH was lower. MWNT exhibited the lowest adsorption capacity toward HOCs because of its low surface area and characteristic of aggregating in aqueous solution.

  2. Adsorptive removal of hydrophobic organic compounds by carbonaceous adsorbents: A comparative study of waste-polymer-based,coal-based activated carbon, and carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Fei Lian; Chun Chang; Yang Du; Lingyan Zhu; Baoshan Xing; Chang Liu

    2012-01-01

    Adsorption of the hydrophobic organic compounds (HOCs) trichloroethylene (TCE),1,3-dichlorobenzene (DCB),1,3-dinitrobenzene (DNB) and γ-hexachlorocyclohexane (HCH) on five different carbonaceous materials was compared.The adsorbents included three polymer-based activated carbons,one coal-based activated carbon (F400) and multiwalled carbon nanotubes (MWNT).The polymerbased activated carbons were prepared using KOH activation from waste polymers:polyvinyl chloride (PVC),polyethyleneterephthalate (PET) and tire rubber (TR).Compared with F400 and MWNT,activated carbons derived from PVC and PET exhibited fast adsorption kinetics and high adsorption capacity toward the HOCs,attributed to their extremely large hydrophobic surface area (2700 m2/g) and highly mesoporous structures.Adsorption of small-sized TCE was stronger on the tire-rubber-based carbon and F400 resulting from the pore-filling effect.In contrast,due to the molecular sieving effect,their adsorption on HCH was lower.MWNT exhibited the lowest adsorption capacity toward HOCs because of its low surface area and characteristic of aggregating in aqueous solution.

  3. Attractive forces between hydrophobic solid surfaces measured by AFM on the first approach in salt solutions and in the presence of dissolved gases.

    Science.gov (United States)

    Azadi, Mehdi; Nguyen, Anh V; Yakubov, Gleb E

    2015-02-17

    Interfacial gas enrichment of dissolved gases (IGE) has been shown to cover hydrophobic solid surfaces in water. The atomic force microscopy (AFM) data has recently been supported by molecular dynamics simulation. It was demonstrated that IGE is responsible for the unexpected stability and large contact angle of gaseous nanobubbles at the hydrophobic solid-water interface. Here we provide further evidence of the significant effect of IGE on an attractive force between hydrophobic solid surfaces in water. The force in the presence of dissolved gas, i.e., in aerated and nonaerated NaCl solutions (up to 4 M), was measured by the AFM colloidal probe technique. The effect of nanobubble bridging on the attractive force was minimized or eliminated by measuring forces on the first approach of the AFM probe toward the flat hydrophobic surface and by using high salt concentrations to reduce gas solubility. Our results confirm the presence of three types of forces, two of which are long-range attractive forces of capillary bridging origin as caused by either surface nanobubbles or gap-induced cavitation. The third type is a short-range attractive force observed in the absence of interfacial nanobubbles that is attributed to the IGE in the form of a dense gas layer (DGL) at hydrophobic surfaces. Such a force was found to increase with increasing gas saturation and to decrease with decreasing gas solubility.

  4. Optimizing the industrial wastewater pretreatment by activated carbon and coagulation: effects of hydrophobicity/hydrophilicity and molecular weights of dissolved organics.

    Science.gov (United States)

    Khan, M Hammad; Ha, Dong-Hwan; Jung, Jinyoung

    2013-01-01

    This study addresses industrial wastewater treatment to remove dissolved organic compounds (DOC) using Fenton and coagulation processes, followed by granular activated carbon (GAC), and powdered activated carbon (PAC) as a pretreatment before reverse osmosis (RO). The effects of the hydrophobic / hydrophilic fractions and the molecular weights (MW) of the organics on DOC removal were tested and used to optimize the combination process. The raw wastewater (RWW) had a dominant hydrophobic fraction, as determined by polymeric resins Amberlite XAD-4. High performance liquid chromatography tandem mass spectrometry (HPLC/MS/MS) results showed that MW of organics were 256, 172, 258, 146, 392, 321, 182, 373, 276, 365, 409 and 453 in increasing order of hydrophobicity. GAC had higher adsorption capacity and was more selective for hydrophobic DOC removal than PAC. The removal efficiency of DOC by PAC and GAC was decreased after Fenton treatment, which decreased the hydrophobic fraction. Coagulation with ferric chloride efficiently removed the non-ionic hydrophilic and anionic hydrophilic organics. The coagulant doses selected as a pretreatment before GAC were 2.1 and 15.5 mg Fe(III)/mg DOC. The effluent total organic carbon (TOC) trends were correlated with the hydrophobic and hydrophilic fractions by using a rapid small-scale column test (RSSCT) for GAC breakthrough with a scale down factor of 5. GAC preferentially adsorbed the hydrophobic and the cationic hydrophilic organics. The effluent TOC trend could be divided into four stages: maximum adsorption, hydrophobic stage, exhaustion, and biological. The TOC removal after the exhaustion stage was almost equal to the hydrophilic fraction of TOC. Therefore these results demonstrated that the combination of coagulation and GAC adsorption was a highly efficient process for reducing DOC.

  5. Hydrophobic interactions and chemical reactivity

    NARCIS (Netherlands)

    Otto, Sijbren; Engberts, Jan B.F.N.

    2003-01-01

    This perspective describes how kinetic studies of organic reactions can be used to increase our understanding of hydrophobic interactions. In turn, our understanding of hydrophobic interactions can be used as a tool to influence chemical reactions.

  6. Hydrophobic interactions and chemical reactivity

    NARCIS (Netherlands)

    Otto, Sijbren; Engberts, Jan B.F.N.

    2003-01-01

    This perspective describes how kinetic studies of organic reactions can be used to increase our understanding of hydrophobic interactions. In turn, our understanding of hydrophobic interactions can be used as a tool to influence chemical reactions.

  7. Mesoscopic Simulations of the Phase Behavior of Aqueous EO 19 PO 29 EO 19 Solutions Confined and Sheared by Hydrophobic and Hydrophilic Surfaces

    KAUST Repository

    Liu, Hongyi

    2012-01-25

    The MesoDyn method is used to investigate associative structures in aqueous solution of a nonionic triblock copolymer consisting of poly(propylene oxide) capped on both ends with poly(ethylene oxide) chains. The effect of adsorbing (hydrophobic) and nonadsorbing (hydrophilic) solid surfaces in contact with aqueous solutions of the polymer is elucidated. The macromolecules form self-assembled structures in solution. Confinement under shear forces is investigated in terms of interfacial behavior and association. The formation of micelles under confinement between hydrophilic surfaces occurs faster than in bulk aqueous solution while layered structures assemble when the polymers are confined between hydrophobic surfaces. Micelles are deformed under shear rates of 1 μs -1 and eventually break to form persistent, adsorbed layered structures. As a result, surface damage under frictional forces is prevented. Overall, this study indicates that aqueous triblock copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) (Pluronics, EO mPO nEO m) act as a boundary lubricant for hydrophobic surfaces but not for hydrophilic ones. © 2011 American Chemical Society.

  8. Model of phase distribution of hydrophobic organic chemicals in cyclodextrin-water-air-solid sorbent systems as a function of salinity, temperature, and the presence of multiple CDs

    Science.gov (United States)

    Blanford, W. J.

    2013-12-01

    Environmental and other applications of cyclodextrins (CD) often require usage of high concentra- tion aqueous solutions of derivatized CDs. In an effort to reduce the costs, these studies also typically use technical grades where the purity of the CD solution and the degree of substitution has not been reported. Further, this grade of CD often included high levels of salt and it is commonly applied in high salinity systems. The mathematical models for water and air partitioning coefficients of hydrophobic organic chemicals (HOC) with CDs that have been used in these studies under-estimate the level of HOC within CDs. This is because those models (1) do not take into account that high concentrations of CDs result in significantly lower levels of water in solution and (2) they do not account for the reduction in HOC aqueous solubility due to the presence of salt. Further, because they have poor knowledge of the CD molar concentration in their solu- tions, it is difficult to draw comparisons between studies. Herein is developed a mathematical model where cyclo- dextrin is treated as a separate phase whose relative volume is calculated from its apparent molar volume in solution and the CD concentration of the solution. The model also accounts for the affects of temperature and the presence of salt in solution through inclusion of modified versions of the Van't Hoff and Setschenow equations. With these capabilities, additional equations have been developed for calculating HOC phase distribution in air-water-CD-solid sorbent systems for a single HOC and between water and CD for a system containing multiple HOCs as well as multiple types of cyclodextrin.

  9. Elimination of hydrophobic volatile organic compounds in fungal biofilters: reducing start-up time using different carbon sources.

    Science.gov (United States)

    Vergara-Fernández, Alberto; Hernández, Sergio; Revah, Sergio

    2011-04-01

    Fungal biofilters have been recently studied as an alternative to the bacterial systems for the elimination of hydrophobic volatile organic compounds (VOC). Fungi foster reduced transport limitation of hydrophobic VOCs due to their hydrophobic surface and extended gas exchange area associated to the hyphal growth. Nevertheless, one of their principal drawbacks is their slow growth, which is critical in the start-up of fungal biofilters. This work compares the use of different carbon sources (glycerol, 1-hexanol, wheat bran, and n-hexane) to reduce the start-up period and sustain high n-hexane elimination capacities (EC) in biofilters inoculated with Fusarium solani. Four parallel experiments were performed with the different media and the EC, the n-hexane partition coefficient, the biomass production and the specific consumption rate were evaluated. Biofilters were operated with a residence time of 1.3 min and an inlet n-hexane load of 325 g m(-3) (reactor) h(-1). The time to attain maximum EC once gaseous n-hexane was fed was reduced in the three experiments with alternate substrates, as compared to the 36 days needed with the control where only n-hexane was added. The shortest adaptation period was 7 days when wheat bran was initially used obtaining a maximum EC of 160 g m(-3) (reactor) h(-1) and a critical load of 55 g m(-3) (reactor) h(-1). The results were also consistent with the pressure drop, the amount of biomass produced and its affinity for the gaseous n-hexane, as represented by its partition coefficient.

  10. Sorption to soil of hydrophobic and ionic organic compounds: measurement and modeling

    NARCIS (Netherlands)

    Laak, Thomas Laurens ter

    2005-01-01

    The sorption of organic compounds to soil, sediments and dissolved organic matter affects the fate of organic compounds. Given the central role of this process in environmental transport, distribution, and (bio)degradation processes, it needs to be well-understood and represented in risk assessment

  11. Effects of salt or cosolvent addition on solubility of a hydrophobic solute in water: Relevance to those on thermal stability of a protein

    Science.gov (United States)

    Murakami, Shota; Hayashi, Tomohiko; Kinoshita, Masahiro

    2017-02-01

    The solubility of a nonpolar solute in water is changed upon addition of a salt or cosolvent. Hereafter, "solvent" is formed by water molecules for pure water, by water molecules, cations, and anions for water-salt solution, and by water and cosolvent molecules for water-cosolvent solution. Decrease and increase in the solubility, respectively, are ascribed to enhancement and reduction of the hydrophobic effect. Plenty of experimental data are available for the change in solubility of argon or methane arising from the addition. We show that the integral equation theory combined with a rigid-body model, in which the solute and solvent particles are modeled as hard spheres with different diameters, can reproduce the data for the following items: salting out by an alkali halide and salting in by tetramethylammonium bromide, increase in solubility by a monohydric alcohol, and decrease in solubility by sucrose or urea. The orders of cation or anion species in terms of the power of decreasing the solubility can also be reproduced for alkali halides. With the rigid-body model, the analyses are focused on the roles of entropy originating from the translational displacement of solvent particles. It is argued by decomposing the solvation entropy of a nonpolar solute into physically insightful constituents that the solvent crowding in the bulk is a pivotal factor of the hydrophobic effect: When the solvent crowding in the bulk becomes more serious, the effect is strengthened, and when it becomes less serious, the effect is weakened. It is experimentally known that the thermal stability of a protein is also influenced by the salt or cosolvent addition. The additions which decrease and increase the solubility of a nonpolar solute, respectively, usually enhance and lower the thermal stability. This suggests that the enhanced or reduced hydrophobic effect is also a principal factor governing the stability change. However, urea decreases the solubility but lowers the stability

  12. Synthesis and toxicity evaluation of hydrophobic ionic liquids for volatile organic compounds biodegradation in a two-phase partitioning bioreactor.

    Science.gov (United States)

    Rodriguez Castillo, Alfredo Santiago; Guihéneuf, Solène; Le Guével, Rémy; Biard, Pierre-François; Paquin, Ludovic; Amrane, Abdeltif; Couvert, Annabelle

    2016-04-15

    Synthesis of several hydrophobic ionic liquids (ILs), which might be selected as good candidates for degradation of hydrophobic volatile organic compounds in a two-phase partitioning bioreactor (TPPB), were carried out. Several bioassays were also realized, such as toxicity evaluation on activated sludge and zebrafish, cytotoxicity, fluoride release in aqueous phase and biodegradability in order to verify their possible effects in case of discharge in the aquatic environment and/or human contact during industrial manipulation. The synthesized compounds consist of alkylimidazoliums, functionalized imidazoliums, isoqinoliniums, triazoliums, sulfoniums, pyrrolidiniums and morpholiniums and various counter-ions such as: PF6(-), NTf2(-) and NfO(-). Toxicity evaluation on activated sludge of each compound (5% v/v of IL) was assessed by using a glucose uptake inhibition test. Toxicity against zebrafish and cytotoxicity were evaluated by the ImPACCell platform of Rennes (France). Fluoride release in water was estimated by regular measurements using ion chromatography equipment. IL biodegradability was determined by measuring BOD28 of aqueous samples (compound concentration,1mM). All ILs tested were not biodegradable; while some of them were toxic toward activated sludge. Isoquinolinium ILs were toxic to human cancerous cell lines. Nevertheless no toxicity was found against zebrafish Danio rerio. Only one IL released fluoride after long-time agitation. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Microplastics as vectors for bioaccumulation of hydrophobic organic chemicals in the marine environment: A state-of-the-science review.

    Science.gov (United States)

    Ziccardi, Linda M; Edgington, Aaron; Hentz, Karyn; Kulacki, Konrad J; Kane Driscoll, Susan

    2016-07-01

    A state-of-the-science review was conducted to examine the potential for microplastics to sorb hydrophobic organic chemicals (HOCs) from the marine environment, for aquatic organisms to take up these HOCs from the microplastics, and for this exposure to result in adverse effects to ecological and human health. Despite concentrations of HOCs associated with microplastics that can be orders of magnitude greater than surrounding seawater, the relative importance of microplastics as a route of exposure is difficult to quantify because aquatic organisms are typically exposed to HOCs from various compartments, including water, sediment, and food. Results of laboratory experiments and modeling studies indicate that HOCs can partition from microplastics to organisms or from organisms to microplastics, depending on experimental conditions. Very little information is available to evaluate ecological or human health effects from this exposure. Most of the available studies measured biomarkers that are more indicative of exposure than effects, and no studies showed effects to ecologically relevant endpoints. Therefore, evidence is weak to support the occurrence of ecologically significant adverse effects on aquatic life as a result of exposure to HOCs sorbed to microplastics or to wildlife populations and humans from secondary exposure via the food chain. More data are needed to fully understand the relative importance of exposure to HOCs from microplastics compared with other exposure pathways. Environ Toxicol Chem 2016;35:1667-1676. © 2016 SETAC.

  14. Effects of Ethylene Oxide Spacer Length on solution Properties of Water—Soluble Fluorocarbon—Containing Hydrophobically Associating Poly(Acrylic Acid—co—Rf—PEG Macromonomer)

    Institute of Scientific and Technical Information of China (English)

    杜立斌; 庄东青; 刘寿平; 章云祥

    2003-01-01

    Poly(acrylic acid)s (PAAs) modified with a series of fluorocarbon group (Rf) end-capped Poly(ethylene glycol) (PEG) macromonomers(number of ethylene oxide unit:1,9,23,45) and corresponding copolymers without fluorocarbon end groups were synthesized.It was found that the effect of the hydrophobic association of fluorocarbon groups on the solution viscosity prevailed over that of the hydrogen bond between grafted PEG and the backbone.Rheological measurement on the aqueous solutions of these poly(acrylic acid-co-Rf-PEG macromonomer) s demonstrated that the best thickening performance was shown when the number of ethylene oxide unit (EO number) was 23.

  15. SOLUBILITY, SORPTION AND TRANSPORT OF HYDROPHOBIC ORGANIC CHEMICALS IN COMPLEX MIXTURES

    Science.gov (United States)

    The research summarized in this report focuses on the effects which organic cosolvents have on the sorption and mobility of organic contaminants. This work was initiated In an effort to improve our understanding of the environmental consequences associated with complex mixtur...

  16. Polar organic solvent added to an aqueous solution changes hydrolytic property of lipase.

    Science.gov (United States)

    Tsuzuki, Wakako; Ue, Akemi; Nagao, Akihiko

    2003-08-01

    For developing further uses of lipase as a biocatalyst, its hydrolytic activity toward some esters was investigated in a miscible solution composed of a buffer and a polar organic solvent. Twenty percent dimethylformamide, 35% dimethylsulfoxide, 15% 1,4-dioxane, 15% dimethoxyethane, and 2% diethoxyethane promoted the hydrolysis by a lipase from Rhizomucor miehei toward some hydrophobic substrates, 4-methylumbelliferyl oleate, 4-methylumbelliferyl palmitate, and monoolein. While hydrolysis by this lipase toward the substrates with a relatively weak hydrophobicity (4-metylumbelliferyl heptanoate and 4-methylumbelliferyl nanoate) was suppressed by these solvents. A fluorometric analysis showed that the polar organic solvent in the buffer induced some conformational change around a tryptophan residue of R. miehei lipase. In addition to the influence of the miscible solvent on the solubility of the substrates, the conformational change of the protein induced by the miscible solvent would also affect the reactive properties of the lipase. Adding a polar organic solvent to an aqueous solution will be an efficient method for changing hydrolytic performance of lipases.

  17. Protecting group and switchable pore-discriminating adsorption properties of a hydrophilic-hydrophobic metal-organic framework

    Science.gov (United States)

    Mohideen, M. Infas H.; Xiao, Bo; Wheatley, Paul S.; McKinlay, Alistair C.; Li, Yang; Slawin, Alexandra M. Z.; Aldous, David W.; Cessford, Naomi F.; Düren, Tina; Zhao, Xuebo; Gill, Rachel; Thomas, K. Mark; Griffin, John M.; Ashbrook, Sharon E.; Morris, Russell E.

    2011-04-01

    Formed by linking metals or metal clusters through organic linkers, metal-organic frameworks are a class of solids with structural and chemical properties that mark them out as candidates for many emerging gas storage, separation, catalysis and biomedical applications. Important features of these materials include their high porosity and their flexibility in response to chemical or physical stimuli. Here, a copper-based metal-organic framework has been prepared in which the starting linker (benzene-1,3,5-tricarboxylic acid) undergoes selective monoesterification during synthesis to produce a solid with two different channel systems, lined by hydrophilic and hydrophobic surfaces, respectively. The material reacts differently to gases or vapours of dissimilar chemistry, some stimulating subtle framework flexibility or showing kinetic adsorption effects. Adsorption can be switched between the two channels by judicious choice of the conditions. The monoesterified linker is recoverable in quantitative yield, demonstrating possible uses of metal-organic frameworks in molecular synthetic chemistry as ‘protecting groups’ to accomplish selective transformations that are difficult using standard chemistry techniques.

  18. Self-organization of amphiphilic macromolecules with local helix structure in concentrated solutions.

    Science.gov (United States)

    Glagolev, M K; Vasilevskaya, V V; Khokhlov, A R

    2012-08-28

    Concentrated solutions of amphiphilic macromolecules with local helical structure were studied by means of molecular dynamic simulations. It is shown that in poor solvent the macromolecules are assembled into wire-like aggregates having complex core-shell structure. The core consists of a hydrophobic backbone of the chains which intertwine around each other. It is protected by the shell of hydrophilic side groups. In racemic mixture of right-hand and left-hand helix macromolecules the wire-like complex is a chain of braid bundles of macromolecules with the same chirality stacking at their ends. The average number of macromolecules in the wire cross-section is close to that of separate bundles observed in dilute solutions of such macromolecules. The effects described here could serve as a simple model of self-organization in solutions of macromolecules with local helical structure.

  19. EFFECT OF HYDROPHILIC AND HYDROPHOBIC ORGANIC MATTER ON AMOXICILLIN AND CEPHALEXIN RESIDUALS REJECTION FROM WATER BY NANOFILTRATION

    Directory of Open Access Journals (Sweden)

    M.A.Zazouli, M.Ulbricht, S. Nasseri, H. Susanto,

    2010-01-01

    Full Text Available Antibiotics such as amoxicillin and cephalexin are a group of pharmaceutical compounds in human medicine practice that have been entered in water bodies. Presence of these compounds in the environment has raised concerns regarding the toxicity to aquatic organisms and the emergence of strains of antibiotic-resistant bacteria. Removal of these substances before entering the aquatic environment as well as water reuse plant is very important. The objective of this investigation was to evaluate the impact of hydrophilic and hydrophobic fractions of Natural Organic Matter (NOM on the removal efficiency of cephalexin and amoxicillin, by using two different commercially available composite NF membranes (TFC-SR2 and TFC-SR3. In addition, the effect of NOM fractions on retention mechanism and permeates flux behavior was studied. Amoxicillin and cephalexin were used as models of antibiotics; alginate and humic acid were used as models of hydrophilic and hydrophobic fractions of NOM, respectively. It was observed that the rejection and permeate flux of amoxicillin and cephalexin were influenced by the membrane characteristics and properties of NOM. The results showed that as the alginate proportion was increased, the rejection improved. The permeate flux decreased with increasing alginate ratio. It was observed that the rejections of amoxicillin and cephalexin in TFC-SR2 were >97.3% and >95.8% in all experiments, respectively. In TFC-SR3, the rejection percentage were (95.9%-100% and (86.1%-96.3%, respectively. Alginate and humic acid had synergistic effect on flux decline. In other words, increasing alginate concentration increased the rate and extent of flux reduction.

  20. Precipitation polymerization of hydrophobically modified polyelectrolyte poly(AA-co-ODA) in supercritical carbon dioxide and solution rheology properties

    Science.gov (United States)

    Zhang, Huaiping; Li, Wei; Cao, Qing; Chen, Mingcai

    2014-05-01

    Hydrophobically modified (HM) polyelectrolytes were prepared by using precipitation polymerization of acrylic acid (AA) and octadecyl acrylate (ODA) in various molar ratios in supercritical carbon dioxide. The product was obtained in the form of a white powder and the micrographs show aggregates of primary particles properties.

  1. The influence of cosolvents on hydrophilic and hydrophobic interactions. Calorimetric studies of parent and alkylated cyclomaltooligosaccharides in concentrated aqueous solutions of ethanol or urea.

    Science.gov (United States)

    Castronuovo, Giuseppina; Niccoli, Marcella

    2008-11-03

    Heats of dilution in water and in aqueous 7 mol kg(-1) urea and 3 mol kg(-1) ethanol of binary solutions containing cyclomaltohexaose, cyclomaltoheptaose, cyclomaltooctaose, 2-hydroxypropyl-cyclomaltohexaose (HPαCD), 2-hydroxypropyl-cyclomaltoheptaose (HPβCD), methyl-cyclomaltohexaose (MeαCD), methyl-cyclomaltoheptaose (MeβCD) and 2-hydroxypropyl-cyclomaltooctaose (HPγCD) have been determined at 298.15K by flow microcalorimetry. The purpose of this study is to gain information about the influence of urea and ethanol, which have different effects on water structure, on hydrophilic and hydrophobic interactions. The pairwise interaction coefficients of the virial expansion of the excess enthalpies were evaluated and compared to those previously obtained for binary solutions of cyclomaltohexaose and cyclomaltoheptaose. The particular behaviour of cyclomaltooligosaccharides in water is put in evidence with respect to that shown by simple oligosaccharides. The values of the interaction coefficients greatly change in dependence of the solvent medium. They are negative in water for unsubstituted cyclomaltooligosaccharides, and positive for the alkyl-substituted ones, thus marking the major role of the hydrophobic interactions. In concentrated aqueous ethanol, coefficients are negative, while they are positive in concentrated aqueous urea. Urea solvates the hydroxyl group provoking the attenuation of hydrophilic and hydrophobic interactions. Instead, the presence of the cosolvent ethanol, which lowers the relative permittivity of the medium, enhances the strength of hydrophilic interactions.

  2. Polarizing a hydrophobic cavity for the efficient binding of organic guests: the case of calix[6]tren, a highly efficient and versatile receptor for neutral or cationic species.

    Science.gov (United States)

    Darbost, Ulrich; Rager, Marie-Noëlle; Petit, Samuel; Jabin, Ivan; Reinaud, Olivia

    2005-06-15

    The host-guest properties of calix[6]tren 1 have been evaluated. The receptor is based on a calix[6]arene that is covalently capped at the narrow rim by a tren unit. As a result, the system presents a concave hydrophobic cavity with, at its bottom, a grid-like nitrogenous core. Despite its well-defined cavity and opening to the outside at the large rim, 1 did not behave as a good receptor for neutral molecules in chloroform. However, it exhibited efficient endo-complexation of ammonium guests. By contrast, the per-protonated host, 1.4H(+), behaved as a remarkable receptor for small organic molecules. The complexation is driven by a strong charge-dipole interaction and hydrogen bonds between the polar guest and the tetracationic cap of the calixarene. Finally, coordination of Zn(2+) to the tren core led to the asymmetrization of calixarene cavity and to the strong but selective endo-binding of neutral ligands. This study emphasizes the efficiency of a receptor presenting a concave hydrophobic cavity that is polarized at its bottom. The resulting combination of charge-dipole, hydrogen bonding, CH-pi, and van der Waals interactions highly stabilizes the supramolecular architectures. Also, importantly, the tren cap allows the tuning of the polarization, offering either a basic (1), a highly charged and acidic (1.4H(+)), or a coordination (1.Zn(2+)) site. As a result, the system proved to be highly versatile, tunable, and interconvertible in solution by simple addition of protons, bases, or metal ions.

  3. Hybrid organic-inorganic silica monolith with hydrophobic/strong cation-exchange functional groups as a sorbent for micro-solid phase extraction.

    Science.gov (United States)

    Zheng, Ming-Ming; Ruan, Ge-Deng; Feng, Yu-Qi

    2009-11-06

    A hybrid organic-inorganic silica monolith with hydrophobic and strong cation-exchange functional groups was prepared and used as a sorbent for micro-solid phase extraction (micro-SPE). The hybrid silica monolith functionalized with octyl and thiol groups was conveniently synthesized by hydrolysis and polycondensation of a mixture of tetraethoxysilane (TEOS), n-octyltriethoxysilane (C8-TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) via a two-step catalytic sol-gel process. Due to the favorable chemical reactivity of mercapto pendant moieties, the obtained hybrid monolith was oxidized using hydrogen peroxide (30%, w/w) to yield sulfonic acid groups, which provided strong cation-exchange sites. The obtained hybrid monolith was characterized by diffused infrared spectroscopy, elemental analysis, scanning electron microscopy and mercury intrusion porosimetry. The results show that the resulting monolith contains much higher carbon (31.6%) and sulfur (4.8%) contents than traditionally bonded silica materials. The extraction performance of the hybrid monolith was evaluated using sulfonamides as testing analytes by micro-SPE on-line coupled to HPLC. The results show that the hybrid monolith with hydrophobic and strong cation-exchange functional groups exhibits high extraction efficiency towards the testing analytes. The column-to-column RSD values were 1.3-9.8% for the extraction of SAs investigated. The extraction performance of the hybrid silica monolith remained practically unchanged after treated with acid (pH 1.0) and basic solutions (pH 10.5). Finally, the application of the hybrid monolith was demonstrated by micro-SPE of sulfonamide residues from milk followed by HPLC-UV analysis. The limits of detection (S/N=3) for eight SAs were found to be 1.0-3.0ng/mL in milk. The recoveries of eight SAs spiked in milk sample ranged from 80.2% to 115.6%, with relative standard deviations less than 11.8%.

  4. Characterization of dissolved organic matter as N-nitrosamine precursors based on hydrophobicity, molecular weight and fluorescence

    Institute of Scientific and Technical Information of China (English)

    Chengkun Wang; Xiaojian Zhang; Jun Wang; Chao Chen

    2013-01-01

    It is very important to identify the dominant precursors for N-nitrosamine formation from bulk organic matter,to enhance the understanding of N-nitrosamine formation pathways in water treatment plants and allow the development of practical treatment technologies.In this study,dissolved organic matter (DOM) from two source waters was fractionated with XAD resins and ultrafiltration membranes.The N-nitrosamine formation potential (FP) (ng of N-nitrosamines formed per mg of dissolved organic carbon (DOC)) from raw water and each fraction were measured and correlated with the fluorescence excitation-emission matrix (EEM),molecular weight (MW) and other assays.The results showed that the hydrophilic fraction had N-nitrosamine FP 1.3 to 3.5 times higher than the hydrophobic fraction from both source waters.The DOM fraction with low MW was the dominant fraction in these two source waters and contributed more precursors for N-nitrosamine formation than the larger MW fraction.The EEM spectra indicated there were notable amounts of soluble microbial products (SMPs) and aromatic proteins in the two studied rivers,which probably originated from wastewater discharge.The SMPs tended to be more closely correlated with N-nitrosodimethylamine formation potential than the other DOM components.Higher N-nitrosamine FP were also related to fractions with lower DOC/DON ratios and lower SUVA254 values.

  5. A modified CZ-1 preserving solution for organ transplantation:comparative study with UW preserving solution

    Institute of Scientific and Technical Information of China (English)

    ZHENG Jun-hua; MIN Zhi-lian; LI Yu-li; ZHU You-hua; YE Ting-jun; LI Jian-qiu; PAN Tie-wen; DING Guo-shan; WANG Meng-long

    2008-01-01

    Background The University of Wisconsin colloid based preserving solution (UW solution) is the most efficient preserving solution for multiorgan transplantation. Unfortunately, unavailability of delayed organ preserving solutions hindered further progression of cardinal organ transplantation in China. In this study, we validated an organ preserving Changzheng Organ Preserving Solution (CZ-1 solution) and compared it with UW solution.Methods A series of studies were conducted on how and how long CZ-1 solution could preserve the kidneys, livers,hearts, lungs and pancreas of New Zealand rabbits and SD rats. Morphology of transplanted organs was studied by visible microscopy and electron microscopy; biochemical and physiological functions and the survival rate of the organs during prolonged cold storage were studied.Results There was no significant difference between CZ-1 and UW solutions in preserving the kidneys, livers, hearts or lungs of rabbits; kidneys, livers, intestinal mucosa or pancreases of SD rats or five deceased donors' testicles. In some aspects, such as preserving rabbits' hearts, rats' intestinal mucosa and pancreases, the effect of CZ-1 solution was superior to UW solution. CZ-1 could safely preserve kidneys for 72 hours, livers for 24 hours, hearts for 18 hours and lungs for 8 hours for SD rats. Twelve kidneys preserved in cold CZ-1 solution for 22-31 hours were transplanted successfully and the mean renal function recovery time was (3.83±1.68) days.Conclusions CZ-1 solution is as effective as UW solution for organ preservation. The development of CZ-1 solution not only reduces costs and improves preservation of organs, but also promotes future development of organ transplantation in China.

  6. Adsorption of phthalic acid esters (PAEs) by amphiphilic polypropylene nonwoven from aqueous solution: the study of hydrophilic and hydrophobic microdomain.

    Science.gov (United States)

    Zhou, Xiangyu; Wei, Junfu; Zhang, Huan; Liu, Kai; Wang, Han

    2014-05-30

    A kind of amphiphilic polypropylene nonwoven with hydrophilic and hydrophobic microdomain was prepared through electron beam induced graft polymerization and subsequent ring opening reaction and then utilized in the adsorption of phthalic acid esters (PAEs). To elucidate the superiority of such amphiphilic microdomain, a unique structure without hydrophilic part was constructed as comparison. In addition, the adsorption behaviors including adsorption kinetics, isotherms and pH effect were systematically investigated. The result indicated that the amphiphilic structure and the synergy between hydrophilic and hydrophobic microdomain could considerably improve the adsorption capacities, rate and affinity. Particularly the existence of hydrophilic microdomain could reduce the diffusion resistance and energy barrier in the adsorption process. These adsorption results showed that the amphiphilic PP nonwoven have the potential to be used in environmental application.

  7. Partitioning of hydrophobic organic contaminants between polymer and lipids for two silicones and low density polyethylene

    DEFF Research Database (Denmark)

    Smedes, Foppe; Rusina, Tatsiana P.; Beeltje, Henry

    2017-01-01

    concentrations in other (defined) media, which however requires appropriate polymer to media partition coefficients. We determined thus polymer-lipid partition coefficients (KPL) of various PCB, PAH and organochlorine pesticides by equilibration of two silicones and low density polyethylene (LDPE) with fish oil...... and Triolein at 4 °C and 20 °C. We observed (i) that KPL was largely independent of lipid type and temperature, (ii) that lipid diffusion rates in the polymers were higher compared to predictions based on their molecular volume, (iii) that silicones showed higher lipid diffusion and lower lipid sorption...... compared to LDPE and (iv) that absorbed lipid behaved like a co-solute and did not affect the partitioning of HOC at least for the smaller molecular size HOC. The obtained KPL can convert measured equilibrium concentrations in passive sampling polymers into equilibrium concentrations in lipid, which...

  8. New modeling paradigms for the sorption of hydrophobic organic chemicals to heterogeneous carbonaceous matter in soils, sediments, and rocks

    Science.gov (United States)

    Allen-King, Richelle M.; Grathwohl, Peter; Ball, William P.

    Heterogeneity in naturally occurring carbonaceous materials (CMs) causes sorbed hydrophobic organic compound (HOC) concentrations in soils, sediments, and rocks to occur as a combination of surface adsorption and phase partitioning, with the latter typically more linearly dependent on aqueous concentration. In this manuscript, we describe a model to simulate HOC sorption as the combined effect of adsorption to thermally altered CM and a more linear solvation-driven absorption into gel-like CM (organic matter). We describe different forms of thermally altered CM (such as soots, chars, coals, and kerogen), the manner in which these materials can serve as especially strong adsorbents, and the conditions under which they can control solid-aqueous distribution. Specific examples of model fits to soil, sediment and rock samples with identified thermally altered CM components provide a linkage between sorption components and sorbent material properties. Because both the adsorption and partition components are scalable by compound solubility, it may often be possible to estimate nonlinear isotherms for a wide range of chemicals based on comparatively few experimental measurements. Thermally altered CM is widespread in the environment and can serve as an important sorbent even when present in small quantities (especially at low concentrations of adsorbates). In this context, the sorption modeling refinements described in this work are expected to have wide applicability. Given that solid/water distribution is a central process affecting contaminant fate, such refined models are an essential element for better estimates of risk and improved remediation design.

  9. Surface Activities of Calix[4] resorcinarenes Bearing Four Hydrophobic Chains and Its Sol ubilization for Organic Compounds

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Calix [4] resorcinarenes bearing four hydrophobic side chains (4] Ar-Rn, [4] Ar-Ph, and [4] Ar-N) orient stably on water oil interface and show high solubilization capacities for organic compounds, such as long-chain alcohols, benzene, toluene and dyes. The capacities are high even near the omc of polyalkylated calix [4] resorcinarenes, but the solubilities of organic compounds(solubilizates) decrease with the increase of the size of the solubilizates. [4] Ar-R6, with a chain-length of six carbons, is the most effective among [4] Ar-Rn,[4] Ar-Ph, and [4] Ar-N; 11-fold mol of hexanol is dissolved in 2×10-3 mol/I [4]Ar-R6. Moreover,[4] Ar-Rn bearing four alkyl side chains solubilizes the chain alcohols of the same chain length mostly. The solubilization capacities are presumably brought by inclusion in a large cavity of the polyalkylated calix[4] resorcinarcnes and by an efficient orientation of the solubilizates.

  10. Capture of nerve agents and mustard gas analogues by hydrophobic robust MOF-5 type metal-organic frameworks.

    Science.gov (United States)

    Montoro, Carmen; Linares, Fátima; Procopio, Elsa Quartapelle; Senkovska, Irena; Kaskel, Stefan; Galli, Simona; Masciocchi, Norberto; Barea, Elisa; Navarro, Jorge A R

    2011-08-10

    In this communication, a series of observations and data analyses coherently confirms the suitability of the novel metal-organic framework (MOF) [Zn(4)(μ(4)-O)(μ(4)-4-carboxy-3,5-dimethyl-4-carboxy-pyrazolato)(3)] (1) in the capture of harmful volatile organic compounds (VOCs). It is worthy of attention that 1, whose crystal structure resembles that of MOF-5, exhibits remarkable thermal, mechanical, and chemical stability, as required if practical applications are sought. In addition, it selectively captures harmful VOCs (including models of Sarin and mustard gas, which are chemical warfare agents), even in competition with ambient moisture (i.e., under conditions mimicking operative ones). The results can be rationalized on the basis of Henry constant and adsorption heat values for the different essayed adsorbates as well as H(2)O/VOC partition coefficients as obtained from variable-temperature reverse gas chromatography experiments. To further strengthen the importance of 1, its performance in the capture of harmful VOCs has been compared with those of well-known materials, namely, a MOF with coordinatively unsaturated metal sites, [Cu(3)(btc)(2)] and the molecular sieve active carbon Carboxen. The results of this comparison show that coordinatively unsaturated metal sites (preferential guest-binding sites) are ineffective for the capture of VOCs in the presence of ambient moisture. Consequently, we propose that the driving force of the VOC-MOF recognition process is mainly dictated by pore size and surface hydrophobicity. © 2011 American Chemical Society

  11. Sorption of four hydrophobic organic contaminants by biochars derived from maize straw, wood dust and swine manure at different pyrolytic temperatures

    Science.gov (United States)

    To study the interactions between biochars and hydrophobic organic compounds (HOCs), the adsorption of HOCs with varied physical-chemical properties on biochars produced from three feedstock sources (maize straw (MABs), pine wood dust (WDBs) and swine manure (SWBs)) was evaluated. The biochars produ...

  12. Diffusion of organic solutes in squalane.

    Science.gov (United States)

    Kowert, Bruce A; Watson, Michael B

    2011-08-18

    The translational diffusion constants, D, of 26 hydrocarbons have been determined in squalane (2,6,10,15,19,23-hexamethyltetracosane) at room temperature using capillary flow techniques. These new data and previously published room-temperature D values for the same solutes in some (or all) of the n-alkanes n-C(6)-n-C(16) constitute a study of solute diffusion in media spanning a 100-fold change in viscosity; at 23 °C, η = 0.31 cP for n-C(6), 3.2 cP for n-C(16), and 30 cP for squalane. The D values in the n-alkanes and squalane show deviations from the Stokes-Einstein relation, D = k(B)T/(6πηr); the values of r, a solute's hydrodynamic radius, decrease as the viscosity increases. The deviations increase as the solute size decreases and are analyzed by fitting the diffusion constants to the modified Stokes-Einstein equation, D/T = A(SE)/η(p). Fits involving the n-alkane-only and combined n-alkane-squalane D values give comparable results with values of p squalane.

  13. MODELING THE FATE AND TRANSPORT OF HYDROPHOBIC ORGANIC COMPOUNDS IN AN UNSTEADY RIVER-ESTUARINE SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Su-Chin CHEN; Jan-Tai KUO

    2002-01-01

    This research develops a generalized,one-dimensional,finite difference model for simulating the distribution of toxic substances in a river-estuarine system. The three sub-models for unsteady flow,sediment transport,and the reaction of toxic substances are also presented using an uncoupled numerical method. The paper also includes experimental work for sorption/desorption,field measurements of organic carbon content in the heavily polluted Keelung River,and a laboratory study of cohesive sediment transport for the model calibration and verification. In addition,this study simulates the polycyclic aromatic hydrocarbons (PAHs) in the Keelung River in northern Taiwan as a case study. Encouraging results are obtained,and suggest that the modeling approach could be extended to simulate the fate and transport of sorbed pollutants in tidal river.

  14. A new anion-exchange/hydrophobic monolith as stationary phase for nano liquid chromatography of small organic molecules and inorganic anions.

    Science.gov (United States)

    Aydoğan, Cemil

    2015-05-01

    In this study, an anion-exchange/hydrophobic polymethacrylate-based stationary phase was prepared for nano-liquid chromatography of small organic molecules and inorganic anions. The stationary phase was synthesized by in situ polymerization of 3-chloro-2-hydroxypropylmethacrylate and ethylene dimethacrylate inside silanized 100 μm i.d. fused silica capillary. The porogen mixture consisted of toluene and dodecanol. The pore size distrubution profiles of the resulting monolith were determined by mercury intrusion porosimetry and the morphology of the prepared monolith was investigated by scanning electron microscope. Good permeability, stability and column efficiency were observed on the monolithic column with nano flow. The produced monolithic column, which contains reactive chloro groups, was then modified by reaction with N,N-dimethyl-N-dodecylamine to obtain an anion-exchange/hydrophobic monolithic stationary phase. The functionalized monolith contained ionizable amine groups and hydrophobic groups that are useful of anion-exchange/hydrophobic mixed-mode chromatography. The final monolithic column performance with respect to anion-exchange and hydrophobic interactions was assesed by the separation of alkylbenzene derivatives, phenolic compounds and inorganic anions, respectively. Theoretical plate numbers up to 23,000 plates/m were successfully achieved in the separation of inorganic anions.

  15. Cation transfer across a hydrogel/organic phase: Effect of cation size, hydrophobicity and acid-base properties

    Energy Technology Data Exchange (ETDEWEB)

    Juarez, Ana V. [Departamento de Quimica Organica, IMBIV, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina); Yudi, Lidia M. [Departamento de Fisico Quimica, INFIQC, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina); Alvarez Igarzabal, Cecilia [Departamento de Quimica Organica, IMBIV, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina); Strumia, Miriam C., E-mail: mcs@fcq.unc.edu.a [Departamento de Quimica Organica, IMBIV, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2010-02-28

    The transfers of tetraethylammonium (TEA{sup +}) and protonated triflupromazine (HTFP{sup +}) through a hydrogel/liquid interface (g/o) and a liquid/liquid interface (w/o) were compared using cyclic voltammetry. After the two phases were put in contact, the behavior of each molecule was analyzed at different pH values and at different time points. The gel induces hydrophobic and electrostatic interactions with TEA{sup +} and HTFP{sup +}, shifting the peak potentials to more positive values. The diffusion coefficients, D, in both phases (g and w) at different pH values were calculated. In the case of TEA{sup +}, the D value remains constant in both systems. However, the D value of HTFP{sup +} is lower in the gel phase than in the liquid phase. HTFP{sup +} is transferred from the aqueous phase to the organic phase via a direct mechanism that involves coupled acid-base and partition processes. At the g/o interface, the coupled chemical reactions of HTFP{sup +} were inhibited by the drug/gel interaction. The results demonstrate that the g/o system could be used as a model to study the controlled release of charged drugs.

  16. Surfactant-soil interactions during surfactant-amended remediation of contaminated soils by hydrophobic organic compounds: a review.

    Science.gov (United States)

    Laha, Shonali; Tansel, Berrin; Ussawarujikulchai, Achara

    2009-01-01

    Surfactants are amphiphilic molecules that reduce aqueous surface tension and increase the solubility of hydrophobic organic compounds (HOCs). Surfactant-amended remediation of HOC-contaminated soils and aquifers has received significant attention as an effective treatment strategy - similar in concept to using soaps and detergents as washing agents to remove grease from soiled fabrics. The proposed mechanisms involved in surfactant-amended remediation include: lowering of interfacial tension, surfactant solubilization of HOCs, and the phase transfer of HOC from soil-sorbed to pseudo-aqueous phase. However, as with any proposed chemical countermeasures, there is a concern regarding the fate of the added surfactant. This review summarizes the current state of knowledge regarding nonionic micelle-forming surfactant sorption onto soil, and serves as an introduction to research on that topic. Surfactant sorption onto soil appears to increase with increasing surfactant concentration until the onset of micellization. Sorbed-phase surfactant may account for the majority of added surfactant in surfactant-amended remediation applications, and this may result in increased HOC partitioning onto soil until HOC solubilization by micellar phase surfactant successfully competes with increased HOC sorption on surfactant-modified soil. This review provides discussion of equilibrium partitioning theory to account for the distribution of HOCs between soil, aqueous phase, sorbed surfactant, and micellar surfactant phases, as well as recently developed models for surfactant sorption onto soil. HOC partitioning is characterized by apparent soil-water distribution coefficients in the presence of surfactant.

  17. Using SPMDs for monitoring hydrophobic organic compounds in urban river water in Korea compared with using conventional water grab samples

    Science.gov (United States)

    Kim, Un-Jung; Kim, Hee Young; Alvarez, David A.; Lee, In-Seok; Oh, Jeong-Eun

    2014-01-01

    We aimed to verify the effectiveness of semi-permeablemembrane devices (SPMDs) formonitoring hydrophobic organic compounds, such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), that are not easy to detect using conventional grab samples (because of their low concentrations), in water.We used SPMDs and grab samples to monitor PCBs and PBDEs upstream and downstream of a sewage treatment plant (STP) in the Suyeong River in Busan, Korea. Concentrations in three different phases (freely dissolved, apparently dissolved, and particulate) were measured, to investigate the aquatic fate of PCBs and PBDEs. The freely dissolved (SPMD) concentrations were 2–3 times higher than the apparently dissolved and particulate phase (grab sample) concentrations. No meaningful relationships were found between the total PCB and PBDE concentrations of the grab sample and SPMD sample because of the different partitioning behaviors and detection frequencies of the individual chemicals. However, the summed concentrations of specific PCB and PBDE congeners (that were abundant in all samples) in the grab and SPMD samples correlated well (r2 = 0.7451 for PCBs 28 + 52 + 153, r2 = 0.9987 for PBDEs 28 + 47 + 99). The PBDE concentrations measured using SPMDs decreased with increasing distance from the STP, but no apparent dilution effect was found in the grab samples. Our results show that SPMDs could be used to support grab sampling for specific chemicals, or to trace chemical sources (such as STPs) to the aquatic environment.

  18. Poly(DL-lactide)-b-poly(N,N-dimethylamino-2-ethyl methacrylate): synthesis, characterization, micellization behavior in aqueous solutions, and encapsulation of the hydrophobic drug dipyridamole.

    Science.gov (United States)

    Karanikolopoulos, Nikos; Zamurovic, Miljana; Pitsikalis, Marinos; Hadjichristidis, Nikos

    2010-02-08

    We synthesized a series of well-defined poly(dl-lactide)-b-poly(N,N-dimethylamino-2-ethyl methacrylate) (PDLLA-b-PDMAEMA) amphiphilic diblock copolymers by employing a three-step procedure: (a) ring-opening polymerization (ROP) of dl-lactide using n-decanol and stannous octoate, Sn(Oct)(2), as the initiating system, (b) reaction of the PDLLA hydroxyl end groups with bromoisobutyryl bromide, and (c) atom transfer radical polymerization, ATRP, of DMAEMA with the newly created bromoisobutyryl initiating site. The aggregation behavior of the prepared block copolymers was investigated by dynamic light scattering and zeta potential measurements at 25 degrees C in aqueous solutions of different pH values. The hydrophobic drug dipyridamole was efficiently incorporated into the copolymer aggregates in aqueous solutions of pH 7.40. High partition coefficient values were determined by fluorescence spectroscopy.

  19. Teamwork – a Solution for Romanian Organizations

    OpenAIRE

    Stan ªtefania Anca

    2013-01-01

    Creating an environment that is built on teamwork and establishing an effective team is a real challenge for any company and it is the responsibility of the organization, the manager or the team leader and of each team member. Thus, Romanian managers are required to have in-depth knowledge of their team hence they can make use of their full potential. The purpose of this paper is to analyze teamwork in the Romanian companies. Based on the analysis of 90 completed questionnaires, we are presen...

  20. Hydrophobic, Porous Battery Boxes

    Science.gov (United States)

    Bragg, Bobby J.; Casey, John E., Jr.

    1995-01-01

    Boxes made of porous, hydrophobic polymers developed to contain aqueous potassium hydroxide electrolyte solutions of zinc/air batteries while allowing air to diffuse in as needed for operation. Used on other types of batteries for in-cabin use in which electrolytes aqueous and from which gases generated during operation must be vented without allowing electrolytes to leak out.

  1. Membrane Dialysis Extraction (MDE): a novel approach for extracting toxicologically relevant hydrophobic organic compounds from soils and sediments for assessment in biotests

    Energy Technology Data Exchange (ETDEWEB)

    Seiler, T.B.; Leist, E.; Braunbeck, T.; Hollert, H. [Dept. of Zoology, Aquatic Ecology and Toxicology, Univ. of Heidelberg (Germany); Rastall, A.C.; Erdinger, L. [Inst. of Hygiene and Medical Microbiology, Univ. of Heidelberg (Germany)

    2006-02-15

    Goal, scope and background. Organic solvents are routinely used to extract toxicants from polluted soils and sediments prior to chemical analysis or bioassay. Conventional extraction methods often require the use of heated organic solvents, in some cases under high pressure. These conditions can result in loss of volatile compounds from the sample and the degradation of thermally labile target analytes. Moreover, extracts of soils and sediments also frequently contain substantial quantities of organic macromolecules which can act as sorbing phases for target analytes and in doing so interfere with both chemical analysis and bioassays. Membrane dialysis extraction (MDE) is described as a simple, passive extraction method for selectively extracting toxicologically relevant hydrophobic organic compounds (HOCs) from polluted soils and sediments and analyzed for its applicability in ecotoxicological investigations. Methods. Toxicologically relevant hydrophobic organic compounds were extracted from wet and dry sediments by sealing replicate samples in individual lengths of pre-cleaned low-density polyethylene (LD-PE) tubing and then dialysing in n-hexane. Results. The membrane dialysis extraction was found to be at least as efficient as Soxhlet methodology to extract toxicologically relevant HOCs from sediment samples. In most cases, MDE-derived extracts showed a higher toxicological potential than the Soxhlet extracts. Lack of any significant effects in any MDE controls indicated these differences were not caused by contamination of the LD-PE membrane used. The elevated toxicological potential of MDE extracts is most likely the result of enhanced bioavailability of toxic compounds in consequence of lower amounts of organic macromolecules (i.e. sorbing phases) in the MDE extracts. This effect is probably the result of a size-selective restriction by the LD-PE membrane. Conclusion. Membrane dialysis extraction was found to be a simple, efficient and cost-effective method

  2. Hydrophobic encapsulation of hydrocarbon gases.

    Science.gov (United States)

    Leontiev, Alexander V; Saleh, Anas W; Rudkevich, Dmitry M

    2007-04-26

    [reaction: see text] Encapsulation data for hydrophobic hydrocarbon gases within a water-soluble hemicarcerand in aqueous solution are reported. It is concluded that hydrophobic interactions serve as the primary driving force for the encapsulation, which can be used for the design of gas-separating polymers with intrinsic inner cavities.

  3. Alternatives for the disposition of PUREX organic solution

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, D.W.

    1995-06-16

    This Supporting Document submits options and recommendations for final management of Tank 40 Plutonium-Uranium Extraction (PUREX) Plant organic solution per Tri-Party Agreement Milestorm Number M-80-00-T03. Hanford is deactivating the PUREX Plant for the US DOE. One the key element of this Deactivation is disposition of approximately 81,300 liters (21,500 gallons) of slightly radioactively contaminated organic solution to reduce risk to the environment, reduce cost of long-term storage, and assure regulatory compliance. An announcement in the Commerce Business Daily (CBD) on October 14, 1994 has resulted in the submission of proposals from two facilities capabLe of receiving and thermally destroying the solution. Total decomposition by thermal destruction is the recommended option for the disposition of the PUREX organic solution and WHC is evaluating the proposals from the two facilities.

  4. Simultaneous Preconcentration and Desalting of Organic Solutes in Aqueous Solutions by Bubble Bursting.

    Science.gov (United States)

    Chingin, Konstantin; Cai, Yunfeng; Liang, Juchao; Chen, Huanwen

    2016-05-17

    Significant efforts are being made to develop more practical and versatile approaches for the preconcentration and purification of complex chemical samples. Inspired by the naturally occurring enrichment of organic compounds in sea aerosols, in this study we demonstrate the potential of induced bubble bursting as an approach for the preconcentration of organic solutes in various aqueous solutions. Apart from the preconcentration of organics, notable decrease in the concentration of metal salt components was discovered for the first time. On the basis of a series of model experiments, the phenomenon has been attributed to intermolecular competition at the surface interface of rising bubbles. Overall, our results indicate the high versatility and simplicity of the bubble bursting approach for the simultaneous preconcentration and desalting of organic solutes in aqueous solutions for mass spectrometry, chromatography, optical detection, and other fields of analysis.

  5. A theoretical analysis of permeation of small hydrophobic solutes across the stratum corneum based on Scaled Particle Theory.

    Science.gov (United States)

    Mitragotri, Samir

    2002-03-01

    The barrier properties of skin originate from its lipid bilayers whose ordered structure retards solute transport. The objective of this study is to develop a mathematical model that can predict skin permeability to small (MW transport properties of skin lipid bilayers. We developed a mathematical model to predict two major transport properties (i.e., partition and diffusion coefficients) using important structural properties of lipid bilayers and molecular properties of the solute. The predictions are based on Scaled Particle Theory that calculates these properties using statistical mechanics of lipid chains. The calculations predict that solute partition coefficients in lipid bilayers are of the same order as those measured in isotropic solvents, such as octanol (K(o/w)). On the other hand, solute diffusion coefficients decrease exponentially with solute cross-sectional area. The resulting equation to predict skin permeability is given by P = 5.6 x 10(-6)K(0.7)(o/w)exp(-0.46r(2)(A1)--where r is solute molecular radius in Angstroms (A) and P is in cm/s. The predicted skin permeabilities compare well with the experimental data.

  6. Abundance and sources of hydrophilic and hydrophobic water-soluble organic carbon at an urban site in Korea in summer.

    Science.gov (United States)

    Park, Seung Shik; Kim, Ja-Hyun; Jeong, Jae-Uk

    2012-01-01

    In this study, the characteristics of total water-soluble organic carbon (WSOC) and isolated WSOC fractions were examined to gain a better understanding of the pathway of organic aerosol production. 24 h PM(2.5) samples were collected during the summer (July 28-August 28, 2009) at an urban site in Korea. A glass column filled with XAD7HP resin was used to separate the filtered extracts into hydrophilic (WSOC(HPI)) and hydrophobic (WSOC(HPO)) fractions. The origins of air mass pathways arriving at the sampling site were mostly classified into three types, those originating over the East Sea of Korea that passed over the eastern inland urban and industrial regions (type I); those from the marine (western/southwestern/southern marine) and passed over the national industrial complex regions (type II); and those from northeastern China that passed through North Korea and metropolitan areas of South Korea (type III). Measurements showed an increase in the average WSOC fraction of total OC from the type II to III air mass (53 to 64%) periods. Also, higher SO(4)(2-)/SO(x) (=SO(2) + SO(4)(2-)) was observed in the type III air mass (0.70) than those in the types I (0.49) and II (0.43). According to the average values of WSOC/OC and SO(4)(2-)/SO(x), measurements suggest that the aerosols collected during the type III air mass period were more aged or photo-chemically processed than those during the types I and II air mass periods. The relationship between the SO(4)(2-)/SO(x) and WSOC/OC (R(2) = 0.64) suggests that a significant fraction of the observed WSOC at the site could be formed by an oxidation process similar to SO(4)(2-) aerosols, probably the oxidation process using OH radicals, or in-cloud processing. The photochemical production of WSOC(HPO) was also observed to significantly contribute to the total OC.

  7. Sorption of apolar and polar organic contaminants by waste tire rubber and its chars in single- and bi-solute systems

    Energy Technology Data Exchange (ETDEWEB)

    Lian Fei; Huang Fang; Chen Wei [College of Environmental Science and Engineering, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Nankai University, Tianjin 300071 (China); Xing Baoshan [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, MA 01003 (United States); Zhu Lingyan, E-mail: zhuly@nankai.edu.cn [College of Environmental Science and Engineering, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Nankai University, Tianjin 300071 (China)

    2011-04-15

    Single- and bi-solute sorption of organic compounds [1,3-dichlorbenzene (DCB), 1,3-dinitrobenzene (DNB) and 2,4-dichlorophenol (DCP)] on ground tire rubber and its chars was studied. The chars were prepared by pyrolyzing tire rubber at different temperatures (200-800 deg. C). Their surface area, aromaticity and hydrophobicity increase greatly with pyrolytic temperature, and the polymeric phase is partly converted into a condensed phase. The sorption of DNB and DCP increases with pyrolytic temperature and is characterized by a transition from a partition dominant to an adsorption dominant process. However, the sorption of DCB linearly decreases with the pyrolytic temperature. The enhanced adsorption of DNB and DCP on carbonized phase is primarily attributed to nonhydrophobic interactions such as {pi}-{pi} electron-donor-acceptor interactions and/or H bonding. The higher partition of DCB to polymeric phase is attributed to its high hydrophobicity. Competitive sorption between DCB and DCP on the tire chars is highly dependent on dissociation of the latter. - Research highlights: > Tire chars consist of dual sorptive domains, i.e., partition and adsorption. > High hydrophobicity of apolar organic contaminant promotes its partition into polymeric phase. > Polar aromatic contaminants show high adsorption on carbonized phase with specific interactions. > Dissociation of ionzable organic chemical heavily influences its sorption on tire chars. - The partition and adsorption of organic contaminants on waste tire chars are highly dependent on the hydrophobicity, polarity and dissociation of solutes.

  8. Mechanism of formation of humus coatings on mineral surfaces 2. Attenuated total reflectance spectra of hydrophobic and hydrophilic fractions of organic acids from compost leachate on alumina

    Science.gov (United States)

    Wershaw, R. L.; Llaguno, E.C.; Leenheer, J.A.; Sperline, R.P.; Song, Y.

    1996-01-01

    Hydrophobic and hydrophilic fractions were isolated from a compost leachate. The adsorption isotherms of both fractions on alumina were measured by attenuated total reflectance infrared spectroscopy. The shapes of the adsorption isotherms of the two fractions were different. The isotherms for the hydrophilic fraction showed little change in surface excess with increasing solution concentration above 4 mg L-1. The isotherms for the hydrophobic fraction, on the other hand, displayed a marked increase in surface excess with increasing solution concentration. This increase is evidence for the formation of aggregates (admicelles or hemimicelles) on the alumina surface. Linear dichroism calculations indicated that more of the carboxylate groups in the adsorbed hydrophobic molecules than in the absorbed hydrophilic fraction were free to rotate. The hindered rotation of the carboxylate groups in the adsorbed hydrophilic-fraction molecules probably indicates that these groups are bound to surface aluminum ions by a bidentate mechanism in which the two oxygen atoms of a single carboxylate group bind to separate aluminum ions.

  9. A thermodynamic approach to assess organic solute adsorption onto activated carbon in water

    KAUST Repository

    De Ridder, David J.

    2012-08-01

    In this paper, the hydrophobicity of 13 activated carbons is determined by various methods; water vapour adsorption, immersion calorimetry, and contact angle measurements. The quantity and type of oxygen-containing groups on the activated carbon were measured and related to the methods used to measure hydrophobicity. It was found that the water-activated carbon adsorption strength (based on immersion calorimetry, contact angles) depended on both type and quantity of oxygen-containing groups, while water vapour adsorption depended only on their quantity. Activated carbon hydrophobicity measurements alone could not be related to 1-hexanol and 1,3-dichloropropene adsorption. However, a relationship was found between work of adhesion and adsorption of these solutes. The work of adhesion depends not only on activated carbon-water interaction (carbon hydrophobicity), but also on solute-water (solute hydrophobicity) and activated carbon-solute interactions. Our research shows that the work of adhesion can explain solute adsorption and includes the effect of hydrogen bond formation between solute and activated carbon. © 2012 Elsevier Ltd. All rights reserved.

  10. A Heuristic Molecular Model of Hydrophobic Interactions

    CERN Document Server

    Hummer, G; García, A E; Pohorille, A; Pratt, L R

    1995-01-01

    Hydrophobic interactions provide driving forces for protein folding, membrane formation, and oil-water separation. Motivated by information theory, the poorly understood nonpolar solute interactions in water are investigated. A simple heuristic model of hydrophobic effects in terms of density fluctuations is developed. This model accounts quantitatively for the central hydrophobic phenomena of cavity formation and association of inert gas solutes; it therefore clarifies the underlying physics of hydrophobic effects and permits important applications to conformational equilibria of nonpolar solutes and hydrophobic residues in biopolymers.

  11. Complex formation of CdSe/ZnS/TOPO nanocrystal vs. molecular chaperone in aqueous solution by hydrophobic interaction

    Energy Technology Data Exchange (ETDEWEB)

    Horiuchi, Hiromi [Department of Applied Physics, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan)]. E-mail: horihiro@cc.tuat.ac.jp; Iwami, Noriya [Department of Applied Physics, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Tachibana, Fumi [Department of Applied Physics, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Ohtaki, Akashi [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Iizuka, Ryo [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Zako, Tamotsu [Bioengineering Laboratory, RIKEN - Institute of Physical and Chemical Research, 2-1, Hirosawa, Wako, Saitama 351-0198 (Japan); Oda, Masaru [Department of Applied Physics, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Strategic Research Initiative for Future Nano-Science and Technology, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Yohda, Masafumi [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Strategic Research Initiative for Future Nano-Science and Technology, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Tani, Toshiro [Department of Applied Physics, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Strategic Research Initiative for Future Nano-Science and Technology, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan)

    2007-11-15

    Feasibilities to stabilize CdSe/ZnS/trioctylphosphineoxide (TOPO) nanocrystals (quantum dots, QDs) in aqueous solutions with prefoldin macromolecules in their bioactive states are reported. Prefoldin is a jellyfish-shaped hexameric co-chaperone of the group II chaperonins. As a protein folding intermediate is captured within its central cavity, so CdSe/ZnS/TOPO QDs would also be included within this cavity. It is also found the QDs can be much more dispersed in aqueous solutions and suspended for certain period of time by adding trace amount of t-butanol in the buffer prior to the mixing of the QDs mother solution. While biochemical procedures are evaluated with ordinary fluorescence measurements, possible complex formations are also evaluated with TIRFM single-molecule detection techniques.

  12. Solute partitioning in aqueous surfactant assemblies: comparison of hydrophobic-hydrophilic interactions in micelles, alcohol-swollen micelles, microemulsions, and synthetic vesicles

    Energy Technology Data Exchange (ETDEWEB)

    Russell, J.C.; Whitten, D.G.

    1982-11-03

    The structures of anionic assemblies including sodium lauryl sulfate (SLS) micelles, alcohol-swollen SLS micelles, microemulsions, and vesicles of a mixture of dipalmitoyllecithin and dicetyl phosphate are investigated by using the ground-state complexation of a hydrophilic quencher (methyl viologen) with several hydrophobic fluorescent probes, including surfactant stilbenes and 1,4-diphenylbutadiene. In SLS micelles this complexation can be decreased nearly an order of magnitude by addition of 1-heptanol, indicating that the structure of the micelle can be adjusted from the highly open structure of the pure micelle to a much more closed structure in which hydrophobic solubilizates can be sequestered from hydrophilic reagents bound to the surface. The fluorescence quenching process in anionic vesicles is strongly dependent on temperature; at low temperatures quenching occurs, while at higher temperatures addition of methyl viologen appears to increase the stilbene fluorescence, indicating that the dicationic quencher binds to the vesicle surface, increasing the order of the system. These results indicate that the degree of organization of surfactant systems can be adjusted by simple changes in composition. 33 references.

  13. Size distributions of hydrophilic and hydrophobic fractions of water-soluble organic carbon in an urban atmosphere in Hong Kong

    Science.gov (United States)

    Wang, Nijing; Yu, Jian Zhen

    2017-10-01

    Water-soluble organic carbon (WSOC) is a significant part of ambient aerosol and plays an active role in contributing to aerosol's effect on visibility degradation and radiation budget through its interactions with atmospheric water. Size-segregated aerosol samples in the range of 0.056-18 μm were collected using a ten-stage impactor sampler at an urban site in Hong Kong over one-year period. The WSOC samples were separated into hydrophilic (termed WSOC_h) and hydrophobic fractions (i.e., the humic-like substances (HULIS) fraction) through solid-phase extraction procedure. Carbon in HULIS accounted for 40 ± 14% of WSOC. The size distribution of HULIS was consistently characterized in all seasons with a dominant droplet mode (46-71%) and minor condensation (9.0-18%) and coarse modes (20-35%). The droplet mode had a mass median aerodynamic diameter in the range of 0.7-0.8 μm. This size mode showed the largest seasonal variation in abundance, lowest in the summer (0.41 μg/m3) and highest in the winter (3.3 μg/m3). WSOC_h also had a dominant droplet mode, but was more evenly distributed among different size modes. Inter-species correlations within the same size mode suggest that the condensation-mode HULIS was partly associated with combustion sources and the droplet-mode was strongly associated with secondary sulfate formation and biomass burning particle aging processes. There is evidence to suggest that the coarse-mode HULIS largely originated from coagulation of condensation-mode HULIS with coarse soil/sea salt particles. The formation process and possible sources of WSOC_h was more complicated and multiple than HULIS and need further investigation. Our measurements indicate that WSOC components contributed a dominant fraction of water-soluble aerosol mass in particles smaller than 0.32 μm while roughly 20-30% in the larger particles.

  14. Role of NH{sub 2}-terminal hydrophobic motif in the subcellular localization of ATP-binding cassette protein subfamily D: Common features in eukaryotic organisms

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Asaka; Asahina, Kota; Okamoto, Takumi; Kawaguchi, Kosuke [Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan); Kostsin, Dzmitry G. [Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan); Institute of Biophysics and Cell Engineering, National Academy of Sciences of Belarus, Academicheskaya Str. 27, Minsk 220072 (Belarus); Kashiwayama, Yoshinori [Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan); Takanashi, Kojiro; Yazaki, Kazufumi [Laboratory of Plant Gene Expression, Research Institute for Sustainable Humanosphere, Kyoko University, Uji, Kyoto 611-0011 (Japan); Imanaka, Tsuneo, E-mail: imanaka@pha.u-toyama.ac.jp [Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan); Morita, Masashi [Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan)

    2014-10-24

    Highlights: • ABCD proteins classifies based on with or without NH{sub 2}-terminal hydrophobic segment. • The ABCD proteins with the segment are targeted peroxisomes. • The ABCD proteins without the segment are targeted to the endoplasmic reticulum. • The role of the segment in organelle targeting is conserved in eukaryotic organisms. - Abstract: In mammals, four ATP-binding cassette (ABC) proteins belonging to subfamily D have been identified. ABCD1–3 possesses the NH{sub 2}-terminal hydrophobic region and are targeted to peroxisomes, while ABCD4 lacking the region is targeted to the endoplasmic reticulum (ER). Based on hydropathy plot analysis, we found that several eukaryotes have ABCD protein homologs lacking the NH{sub 2}-terminal hydrophobic segment (H0 motif). To investigate whether the role of the NH{sub 2}-terminal H0 motif in subcellular localization is conserved across species, we expressed ABCD proteins from several species (metazoan, plant and fungi) in fusion with GFP in CHO cells and examined their subcellular localization. ABCD proteins possessing the NH{sub 2}-terminal H0 motif were localized to peroxisomes, while ABCD proteins lacking this region lost this capacity. In addition, the deletion of the NH{sub 2}-terminal H0 motif of ABCD protein resulted in their localization to the ER. These results suggest that the role of the NH{sub 2}-terminal H0 motif in organelle targeting is widely conserved in living organisms.

  15. Multi-responsive metal-organic lantern cages in solution.

    Science.gov (United States)

    Brega, Valentina; Zeller, Matthias; He, Yufan; Lu, H Peter; Klosterman, Jeremy K

    2015-03-25

    Soluble copper-based M4L4 lantern-type metal-organic cages bearing internal amines were synthesized. The solution state integrity of the paramagnetic metal-organic cages was demonstrated using NMR, DLS, MS, and AFM spectroscopy. 1D supramolecular pillars of pre-formed cages or covalent host-guest complexes selectively formed upon treatment with 4,4'-bipyridine and acetic anhydride, respectively.

  16. Hydrophobic interactions leading to a complex interplay between bioelectrocatalytic properties and multilayer meso-organization in layer-by-layer assemblies.

    Science.gov (United States)

    Lorena Cortez, M; De Matteis, Nicolás; Ceolín, Marcelo; Knoll, Wolfgang; Battaglini, Fernando; Azzaroni, Omar

    2014-10-14

    The present study explores the development of mesostructured bioelectrochemical interfaces with accurate compositional and topological control of the supramolecular architecture through the layer-by-layer assembly of ternary systems based on poly(allylamine) containing an osmium polypyridyl complex (OsPA), an anionic surfactant, sodium dodecyl sulfate (SDS) or sodium octodecyl sulfate (ODS), and glucose oxidase (GOx). We show that the introduction of the anionic surfactant allows a sensitive increase of the polyelectrolyte and the enzyme uptake at pH 7.0, enhancing its catalytic behavior in the presence of glucose as compared to the surfactant-free system (OsPA/GOx)n constructed at the same pH. Structural characterization of the multilayer films was performed by means of grazing-incidence small-angle X-ray scattering (GISAXS), which showed the formation of mesostructured domains within the composite assemblies. Experimental results indicate that the balance between ionic and hydrophobic interactions plays a leading role not only in the construction of the self-assembled system but also in the functional properties of the bioactive interface. The structure of the ternary multilayered films depends largely on the length of the alkyl chain of the surfactant. We show that surfactants incorporated into the film also play a role as chemical entities capable of tuning the hydrophobicity of the whole assembly. In this way, the deliberate introduction of short-range hydrophobic forces was exploited as an additional variable to manipulate the adsorption and coverage of protein during each assembly step. However, the integration of long-chain surfactants may lead to the formation of very well-organized interfacial architectures with poor electron transfer properties. This, in turn, leads to a complex trade-off between enzyme coverage and redox wiring that is governed by the meso-organization and the hydrophobic characteristics of the multilayer assembly.

  17. Phase transfer of platinum nanoparticles from aqueous to organic solutions using fatty amine molecules

    Indian Academy of Sciences (India)

    Ashavani Kumar; Hrushikesh M Joshi; Anandrao B Mandale; Rajendra Srivastava; Suguna D Adyanthaya; Renu Pasricha; Murali Sastry

    2004-08-01

    In this report we demonstrate a simple process based on amine chemistry for the phase transfer of platinum nanoparticles from an aqueous to an organic solution. The phase transfer was accomplished by vigorous shaking of a biphasic mixture of platinum nanoparticles synthesised in an aqueous medium and octadecylamine (ODA) in hexane. During shaking of the biphasic mixture, the aqueous platinum nanoparticles complex via either coordination bond formation or weak covalent interaction with the ODA molecules present in the organic phase. This process renders the nanoparticles sufficiently hydrophobic and dispersible in the organic phase. The ODA-stabilised platinum nanoparticles could be separated out from hexane in the form of a powder that is readily redispersible in weakly polar and nonpolar organic solvents. The ODA-capped platinum nanoparticles show high catalytic activity in hydrogenation reactions and this is demonstrated in the efficient conversion of styrene to ethyl benzene. The nature of binding of the ODA molecules to the platinum nanoparticles surface was characterised by thermogravimetry, transmission electron microscopy (TEM), X-ray photoemission spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR).

  18. Dynamic characterization of hydrophobic and hydrophilic solutes in oleic-acid enhanced transdermal delivery using two-photon fluorescence microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tseng, Te-Yu; Yang, Chiu-Sheng; Chen, Yang-Fang [Department of Physics, National Taiwan University, Taipei, Taiwan (China); Tsai, Tsung-Hua [Department of Dermatology, Far Eastern Memorial Hospital, New Taipei City, Taiwan (China); Dong, Chen-Yuan, E-mail: cydong@phys.ntu.edu.tw [Department of Physics, National Taiwan University, Taipei, Taiwan (China); Center for Quantum Science and Engineering, National Taiwan University, Taipei, Taiwan (China); Center for Optoelectronic Biomedicine, National Taiwan University, Taipei, Taiwan (China)

    2014-10-20

    In this letter, we propose an efficient methodology of investigating dynamic properties of sulforhodamine B and rhodamine B hexyl ester molecules transporting across ex-vivo human stratum corneum with and without oleic acid enhancement. Three-dimensional, time-lapse fluorescence images of the stratum corneum can be obtained using two-photon fluorescence microscopy. Furthermore, temporal quantifications of transport enhancements in diffusion parameters can be achieved with the use of Fick's second law. Dynamic characterization of solutes transporting across the stratum corneum is an effective method for understanding transient phenomena in transdermal delivery of probe molecules, leading to improved delivery strategies of molecular species for therapeutic purposes.

  19. All-solution processed organic solar cells with top illumination

    NARCIS (Netherlands)

    Patil, B.R.; Shanmugam, S.; Teunissen, J.P.; Galagan, Y.

    2015-01-01

    All-solution processed organic solar cells with inverted device architecture were demonstrated. Devices contain opaque bottom electrodes and semitransparent top electrodes, resulting in top illuminated devices. Nanoparticles-based Ag ink was used for inkjet printing both top and bottom electrodes.

  20. All-solution processed organic solar cells with top illumination

    NARCIS (Netherlands)

    Patil, B.R.; Shanmugam, S.; Teunissen, J.P.; Galagan, Y.

    2015-01-01

    All-solution processed organic solar cells with inverted device architecture were demonstrated. Devices contain opaque bottom electrodes and semitransparent top electrodes, resulting in top illuminated devices. Nanoparticles-based Ag ink was used for inkjet printing both top and bottom electrodes. S

  1. All-solution-processed organic solar cells with conventional architecture

    NARCIS (Netherlands)

    Franeker, J.J. van; Voorthuijzen, W.P.; Gorter, H.; Hendriks, K.H.; Janssen, R.A.J.; Hadipour, A.; Andriessen, H.A.J.M.; Galagan, Y.O.

    2013-01-01

    Abstract All-solution processed organic solar cells with a conventional device structure were demonstrated. The evaporated low work function LiF/Al electrode was replaced by a printed high work function silver electrode combined with an additional electron transport layer (ETL). Two electron transpo

  2. Osmotic potential calculations of inorganic and organic aqueous solutions over wide solute concentration levels and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Cochrane, T. T., E-mail: agteca@hotmail.com [AGTECA S.A., 230 Oceanbeach Road, Mount Maunganui, Tauranga 3116 (New Zealand); Cochrane, T. A., E-mail: tom.cochrane@canterbury.ac.nz [Department of Civil and Natural Resources Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand)

    2016-01-15

    Purpose: To demonstrate that the authors’ new “aqueous solution vs pure water” equation to calculate osmotic potential may be used to calculate the osmotic potentials of inorganic and organic aqueous solutions over wide ranges of solute concentrations and temperatures. Currently, the osmotic potentials of solutions used for medical purposes are calculated from equations based on the thermodynamics of the gas laws which are only accurate at low temperature and solute concentration levels. Some solutions used in medicine may need their osmotic potentials calculated more accurately to take into account solute concentrations and temperatures. Methods: The authors experimented with their new equation for calculating the osmotic potentials of inorganic and organic aqueous solutions up to and beyond body temperatures by adjusting three of its factors; (a) the volume property of pure water, (b) the number of “free” water molecules per unit volume of solution, “N{sub f},” and (c) the “t” factor expressing the cooperative structural relaxation time of pure water at given temperatures. Adequate information on the volume property of pure water at different temperatures is available in the literature. However, as little information on the relative densities of inorganic and organic solutions, respectively, at varying temperatures needed to calculate N{sub f} was available, provisional equations were formulated to approximate values. Those values together with tentative t values for different temperatures chosen from values calculated by different workers were substituted into the authors’ equation to demonstrate how osmotic potentials could be estimated over temperatures up to and beyond bodily temperatures. Results: The provisional equations formulated to calculate N{sub f}, the number of free water molecules per unit volume of inorganic and organic solute solutions, respectively, over wide concentration ranges compared well with the calculations of N{sub f

  3. Analysis of Discharged Gas from Incinerator using Simulated Organic Solution

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seungil; Kim, Hyunki; Heo, Jun; Kang, Dukwon [HaJI Co., Ltd., Radiation Eng. Center, Siheung (Korea, Republic of); Kim, Yunbok; Kwon, Youngbock [KORAD, Daejeon (Korea, Republic of)

    2014-05-15

    Korea has no experience of treatment of RI organic waste and appropriate measures for treatment of organic waste did not suggested. RI organic wastes which are occurring in KOREA are stored at the RI waste storage building of KORAD. But they can't no more receive the RI organic waste because the storage facility for RI organic waste was saturated with these organic wastes. In case of Japan, they recognized the dangerousness of long-term storage for RI organic wastes. In case of Korea, the released concentration of gaseous pollutant from the incinerator is regulated by attached table No.1 of the Notification No. 2012-60 of Nuclear Safety Commission and attached table No.8 of Clean Air Conservation Act. And the dioxin from the incinerator is regulated by attached table No.3 of Persistent Organic Pollutants Control Act. This experiment was performed to examine whether the incinerator introduced from Japan is manufactured suitably for municipal law regulation and to confirm the compliance about the gaseous pollutant released from incinerator with the above-mentioned laws especially attached table No.1 of NSC using simulated organic waste solution. In this experiment, we examined whether the incinerator was manufactured suitably for municipal law regulation and confirmed the compliance about the gaseous pollutant released from incinerator with the above-mentioned laws using simulated organic waste solution. The design requirement of incinerator for RI organic waste in the municipal law regulation is proposed briefly but the requirements for more detail about the incinerator are proposed in regulation of Japan. The incinerator used in this experiment is satisfied with all clauses of the domestic as well as Japan. Multiple safety functions were installed in the incinerator such as air purge system to remove unburned inflammable gases in the furnace and earthquake detector. Also, perfect combustion of RI organic waste is achieved because the temperature in the furnace

  4. One-step synthesis of layered yttrium hydroxides in immiscible liquid–liquid systems: Intercalation of sterically-bulky hydrophobic organic anions and doping of europium ions

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Mebae; Fujihara, Shinobu, E-mail: shinobu@applc.keio.ac.jp

    2014-02-15

    Inorganic–organic layered rare-earth compounds were synthesized on the basis of a biphasic liquid–liquid system in one pot. Layered yttrium hydroxides (LYHs) were chosen as a host material for the intercalation of hydrophobic organic guest anions such as benzoate, sebacate, or laurate. In a typical synthesis, an organic phase dissolving carboxylic acid was placed in contact with an equal amount of an aqueous phase dissolving yttrium nitrate n-hydrate and urea. At elevated temperatures up to 80 °C, urea was hydrolyzed to release hydroxyl anions which were used to form yttrium hydroxide layers. LYHs were then precipitated with the intercalation of carboxylate anions delivered from the organic phase under the distribution law. The structure and the morphology of the LYHs could be modulated by the intercalated anions. Doped with Eu{sup 3+} ions, the LYHs exhibited red photoluminescence which was enhanced by the intercalated anions due to the antenna effect. - Graphical abstract: The Eu{sup 3+}-doped layered yttrium hydroxide exhibits intense red photoluminescence after intercalation of benzoate ions. Display Omitted - Highlights: • Immiscible biphasic liquid systems were introduced to synthesize layered yttrium hydroxides. • The temperature of the biphasic systems does not exceed 80 °C in one step of the synthesis. • Hydrophobic organic anions were intercalated between the hydroxide layers in one pot. • Structure and morphology of the hydroxides were modulated by changing the kind of organic anions. • Eu{sup 3+}-doping led to red luminescence from the hydroxides in association with the intercalated organic anions.

  5. Organic solar cells with solution-processed graphene transparent electrodes

    Science.gov (United States)

    Wu, Junbo; Becerril, Héctor A.; Bao, Zhenan; Liu, Zunfeng; Chen, Yongsheng; Peumans, Peter

    2008-06-01

    We demonstrate that solution-processed graphene thin films can serve as transparent conductive anodes for organic photovoltaic cells. The graphene electrodes were deposited on quartz substrates by spin coating of an aqueous dispersion of functionalized graphene, followed by a reduction process to reduce the sheet resistance. Small molecular weight organic solar cells can be directly deposited on such graphene anodes. The short-circuit current and fill factor of these devices on graphene are lower than those of control device on indium tin oxide due to the higher sheet resistance of the graphene films. We anticipate that further optimization of the reduction conditions will improve the performance of these graphene anodes.

  6. Organ donation after assisted suicide: a potential solution to the organ scarcity problem.

    Science.gov (United States)

    Shaw, David M

    2014-08-15

    Switzerland has low deceased organ donation rates. It is also one of the few countries where assisted suicide is decriminalized in some circumstances. If organs donated by Swiss and foreign citizens assisted in committing suicide in Switzerland were used for transplantation, the country could achieve a surplus of organs. There are several practical problems and ethical and legal objections to this proposal, all of which can be overcome. Organ donation after planned death is a potential solution to the organ scarcity problem in any country that permits assisted dying.

  7. Investigations on renal organic and inorganic solutes, in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, S.D.

    1989-01-01

    A basic question in renal physiology is how do the cells of the renal medulla survive the high concentrations of sodium chloride and urea which occur with antidiuresis. The problem is two-fold: (1) urea, being highly permeable to cell membranes, should enter the cell and adversely affect protein function; and (2) inorganic ions, being in much higher concentration extracellularly than intracellularly should dehydrate the cell. If these organic solutes exist in response to high concentrations of sodium chloride and urea, then their content should vary with diuretic state. Two protocols were developed to test the validity of this hypothesis. The first protocol used {sup 31}P-NMR in vivo to monitor GPC content before, during, and after acute diuresis in an exteriorized rabbit kidney model. Changes in sodium distribution and tissue structure were monitored dynamically with {sup 23}Na- and {sup 1}H-NMR imaging, respectively. The second protocol used HPLC to quantitate each of the four organic solutes in renal inner medullary homogenates. Here, the effect of diuretic state and acute diuresis on organic solute content was assessed.

  8. A Heuristic Molecular Model of Hydrophobic Interactions

    OpenAIRE

    Hummer, G; Garde, S; Garcia, A.E.; Pohorille, A; Pratt, L.R.

    1995-01-01

    Hydrophobic interactions provide driving forces for protein folding, membrane formation, and oil-water separation. Motivated by information theory, the poorly understood nonpolar solute interactions in water are investigated. A simple heuristic model of hydrophobic effects in terms of density fluctuations is developed. This model accounts quantitatively for the central hydrophobic phenomena of cavity formation and association of inert gas solutes; it therefore clarifies the underlying physics...

  9. Solute transport model for trace organic neutral and charged compounds through nanofiltration and reverse osmosis membranes.

    Science.gov (United States)

    Kim, Tae-Uk; Drewes, Jörg E; Scott Summers, R; Amy, Gary L

    2007-09-01

    Rejection of trace organic compounds, including disinfection by-products (DBPs) and pharmaceutical active compounds (PhACs), by high-pressure membranes has become a focus of public interest internationally in both drinking water treatment and wastewater reclamation/reuse. The ability to simulate, or even predict, the rejection of these compounds by high-pressure membranes, encompassing nanofiltration (NF) and reverse osmosis (RO), will improve process economics and expand membrane applications. The objective of this research is to develop a membrane transport model to account for diffusive and convective contributions to solute transport and rejection. After completion of cross-flow tests and diffusion cell tests with target compounds, modeling efforts were performed in accordance with a non-equilibrium thermodynamic transport equation. Comparing the percentages of convection and diffusion contributions to transport, convection is dominant for most compounds, but diffusion is important for more hydrophobic non-polar compounds. Convection is also more dominant for looser membranes (i.e., NF). In addition, higher initial compound concentrations and greater J(0)/k ratios contribute to solute fluxes more dominated by convection. Given the treatment objective of compound rejection, compound transport and rejection trends are inversely related.

  10. Hierarchically Organized Iterative Solutions of the Evolution Equations in QCD

    CERN Document Server

    Jadach, S; Was, Z

    2007-01-01

    The task of Monte Carlo simulation of the evolution of the parton distributions in QCD and of constructing new parton shower Monte Carlo algorithms requires new way of organizing solutions of the QCD evolution equations, in which quark-gluon transitions on one hand and quark-quark or gluon-gluon transitions (pure gluonstrahlung) on the other hand, are treated separately and differently. This requires certain reorganization of the iterative solutions of the QCD evolution equations and leads to what we refer to as a hierarchic iterative solutions of the evolution equations. We present three formal derivations of such a solution. Results presented here are already used in the other recent works to formulate new MC algorithms for the parton-shower-like implementations of the QCD evolution equations. They are primarily of the non-Markovian type. However, such a solution can be used for the Markovian-type MCs as well. We also comment briefly on the relation of the presented formalism to similar methods used in othe...

  11. Countercurrent Chromatographic Separation of Lipophilic Ascorbic Acid Derivatives and Extract from Kadsura Coccinea Using Hydrophobic Organic-Aqueous Two-Phase Solvent Systems.

    Science.gov (United States)

    Shinomiya, Kazufusa; Li, Heran; Kitanaka, Susumu; Ito, Yoichiro

    2009-01-01

    Countercurrent chromatographic (CCC) separation of lipophilic ascorbic acid derivatives and the crude extract from Kadsura Coccinea was performed using the type-J multilayer coil planet centrifuge with a hydrophobic organic-aqueous two-phase solvent system composed of n-hexane/ethyl acetate/ethanol/aqueous 0.1% trifluoroacetic acid at the volume ratio of (5 : 5 : 6 : 2). The lipophilic ascorbic acid derivatives were separated in the order of L-ascrobyl 2,6-dibutyrate, L-ascorbyl 6-palmitate and L-ascorbyl 6-stearate by eluting the lower phase as the mobile phase, and L-ascorbyl 2,6-dipalmitate was separated by eluting the upper phase at the opposite direction. The above solvent system was then applied to the CCC separation of the extract prepared from K. coccinea. With lower phase mobile, the extract was mainly separated into two peaks corresponding to lignans and triterpenoids accordingly. The HPLC analysis of the fractions showed that the former peak contained Kadsulignan N, Schizandrin H and Neokadsuranin as lignans, and the latter peak, Micranoic acid A, Neokadsuranic acid B and beta-Sitosterol as triterpenoids. The overall results indicate that the hydrophobic organic-aqueous two-phase solvent system used in the present studies was useful for the CCC separation of lignans and triterpenoids present in the natural products.

  12. Self-organization of poly(ethylene oxide) on the surface of aqueous salt solutions.

    Science.gov (United States)

    Fuchs, Christian; Hussain, Hazrat; Amado, Elkin; Busse, Karsten; Kressler, Joerg

    2015-01-01

    It is demonstrated that stable Langmuir films of poly(ethylene oxide) (PEO) can be formed up to surface pressures of 30 mN m(-1) when potassium carbonate K2CO3 is added to the aqueous subphase. Generally, PEO homopolymer cannot stay on the water surface at a surface pressure ≥10 mN m(-1) due to its high water solubility. To prepare stable monolayer films, PEO can be modified with hydrophobic moieties. However, by exploiting the salting out effect by adding certain salts (K2CO3 or MgSO4) into the aqueous subphase, not only very stable films but also unusual self-organization can be achieved by the PEO homopolymer on the surface of the aqueous solution. Thus, a series of OH-terminated PEOs is found to form a stable monolayer at K2CO3 concentrations of 2 M and above in the aqueous subphase, and the stability of the film increases with an increase in K2CO3 concentration. Hysteresis experiments are also carried out. During the phase transition induced by progressive compression, self-organization into well-defined domains with sizes in the micrometer range are observed, and with further compression and holding of the film for 30 min and above the microdomains transform into a crystalline morphology as visualized by Brewster angle microscopy. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Hydrophobic organic chemicals (HOCs) removal from biologically treated landfill leachate by powder-activated carbon (PAC), granular-activated carbon (GAC) and biomimetic fat cell (BFC).

    Science.gov (United States)

    Liyan, Song; Youcai, Zhao; Weimin, Sun; Ziyang, Lou

    2009-04-30

    Biological pretreatment efficiently remove organic matter from landfill leachate, but further removal of refractory hydrophobic organic chemicals (HOCs) is hard even with advanced treatment. In this work, three-stage-aged refuse bioreactor (ARB) efficiently removed chemical oxygen demand (COD) and biochemical oxygen demand (BOD) of fresh leachate produced in Shanghai laogang landfill, from 8603 to 451 mg L(-1) and 1368 to 30 mg L(-1), respectively. In downstream treatment, 3 g L(-1) powder-activated carbon (PAC), granular-activated carbon (GAC) and biomimetic fat cell (BFC) removed 89.2, 73.4 and 81.1% HOCs, but only 24.6, 19.1 and 8.9% COD, respectively. Through the specific HOCs accumulation characteristics of BFC, about 11.2% HOCs with low molecular weight (effluent exhibited a wide molecular weight distribution (34-514,646 Da). These constitutes are derived from both autochthonous and allochthonous matters as well as biological activities.

  14. Influence of dissolved organic matter and manganese oxides on metal speciation in soil solution: A modelling approach.

    Science.gov (United States)

    Schneider, Arnaud R; Ponthieu, Marie; Cancès, Benjamin; Conreux, Alexandra; Morvan, Xavier; Gommeaux, Maxime; Marin, Béatrice; Benedetti, Marc F

    2016-06-01

    Trace element (TE) speciation modelling in soil solution is controlled by the assumptions made about the soil solution composition. To evaluate this influence, different assumptions using Visual MINTEQ were tested and compared to measurements of free TE concentrations. The soil column Donnan membrane technique (SC-DMT) was used to estimate the free TE (Cd, Cu, Ni, Pb and Zn) concentrations in six acidic soil solutions. A batch technique using DAX-8 resin was used to fractionate the dissolved organic matter (DOM) into four fractions: humic acids (HA), fulvic acids (FA), hydrophilic acids (Hy) and hydrophobic neutral organic matter (HON). To model TE speciation, particular attention was focused on the hydrous manganese oxides (HMO) and the Hy fraction, ligands not considered in most of the TE speciation modelling studies in soil solution. In this work, the model predictions of free ion activities agree with the experimental results. The knowledge of the FA fraction seems to be very useful, especially in the case of high DOM content, for more accurately representing experimental data. Finally, the role of the manganese oxides and of the Hy fraction on TE speciation was identified and, depending on the physicochemical conditions of the soil solution, should be considered in future studies.

  15. Solution-processable organic dielectrics for graphene electronics

    Science.gov (United States)

    Mattevi, Cecilia; Colléaux, Florian; Kim, HoKwon; Lin, Yen-Hung; Park, Kyung T.; Chhowalla, Manish; Anthopoulos, Thomas D.

    2012-08-01

    We report the fabrication, at low-temperature, of solution processed graphene transistors based on carefully engineered graphene/organic dielectric interfaces. Graphene transistors based on these interfaces show improved performance and reliability when compared with traditional SiO2 based devices. The dielectric materials investigated include Hyflon AD (Solvay), a low-k fluoropolymer, and various organic self-assembled monolayer (SAM) nanodielectrics. Both types of dielectric are solution processed and yield graphene transistors with similar operating characteristics, namely high charge carrier mobility, hysteresis free operation, negligible doping effect and improved operating stability as compared to bare SiO2 based devices. Importantly, the use of SAM nanodielectrics enables the demonstration of low operating voltage ( < |1.5| V), solution-processable and flexible graphene transistors with tunable doping characteristics through molecular engineering of the SAM’s molecular length and terminal group. The work is a significant step towards graphene microelectronics where large-volume and low-temperature processing are required.

  16. Solution processed organic bulk heterojunction tandem solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, Steve; Neher, Dieter [Soft Matter Physics, University of Potsdam, D-14476 Potsdam (Germany)

    2011-07-01

    One of the critical issues regarding the preparation of organic tandem solar cells from solution is the central recombination contact. This contact should be highly transparent and conductive to provide high recombination currents. Moreover it should protect the 1st subcell from the solution processing of the 2nd subcell. Here, we present a systematic study of various recombination contacts in organic bulk heterojunction tandem solar cells made from blends of different polymers with PCBM. We compare solution processed recombination contacts fabricated from metal-oxides (TiO{sub 2} and ZnO) and PEDOT:PSS with evaporated recombination contacts made from thin metal layers and molybdenum-oxide. The solar cell characteristics as well as the morphology of the contacts measured by AFM and SEM are illustrated. To compare the electrical properties of the varying contacts we show measurements on single carrier devices for different contact-structures. Alongside we present the results of optical modeling of the subcells and the complete tandem device and relate these results to experimental absorption and reflection spectra of the same structures. Based on these studies, layer thicknesses were adjusted for optimum current matching and device performance.

  17. Comparing the Spectroscopic and Molecular Characteristics of Different Dissolved Organic Matter Fractions Isolated by Hydrophobic and Anionic Exchange Resins Using Fluorescence Spectroscopy and FT-ICR-MS

    Directory of Open Access Journals (Sweden)

    Morgane Derrien

    2017-07-01

    Full Text Available Despite the environmental significance of dissolved organic matter (DOM, characterizing DOM is still challenging due to its structural complexity and heterogeneity. In this study, three different chemical fractions, including hydrophobic acid (HPOA, transphilic acid (TPIA, and hydrophilic neutral and base (HPIN/B fractions, were separated from bulk aquatic DOM samples, and their spectral features and the chemical composition at the molecular level were compared using both fluorescence excitation emission matrix-parallel factor analysis (EEM-PARAFAC and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS. The HPIN/B fraction was distinguished from the two acidic fractions (i.e., HPOA and TPIA by the EEM-PARAFAC, while the TPIA fraction was discriminated by using the molecular parameters derived from the FT-ICR MS analyses. Statistical comparison suggests that the spectral dissimilarity among the three chemical fractions might result from the acido-basic properties of DOM samples, while the differences in molecular composition were more likely to be affected by the hydrophobicity of the DOM fractions. The non-metric multidimensional scaling map further revealed that the HPOA was the most heterogeneous among the three fractions. The number of overlapping formulas among the three chemical fractions constituted only <5% of all identified formulas, and those between two different fractions ranged from 2.0% to 24.1%, implying relatively homogeneous properties of the individual chemical fractions with respect to molecular composition. Although employing chemical fractionation achieved a lowering of the DOM heterogeneity, prevalent signatures of either acido-basic property or the hydrophobic nature of DOM on the characteristics of three chemical isolated fractions were not found for this study.

  18. Fully solution-processed, transparent organic power-generating polarizer

    Science.gov (United States)

    Chou, Wei-Yu; Hsu, Fang-Chi; Chen, Yang-Fang

    2017-03-01

    We fabricate transparent organic power-generating polarizer by all solution process. Based on the conventional indium–tin-oxide-coated glass as the bottom cathode, the subsequent layers are prepared by a combination of solution processing methods. Sprayed silver nanowires film serves as the top anode and can transmit greater than 80% of the visible light with sheet resistance of 16 Ω/□. By adopting the quasi-bilayer structure for the photoactive layer composed of rubbed polymer donors to produce anisotropic optical property underneath fullerene acceptors, the finished device demonstrates a power conversion efficiency of 1.36% with unpolarized light, a dichroic ratio of 3.2, and a high short circuit current ratio of 2.6 with polarized light. Our proposed fabrication procedures of devices take into account not only the cost-effective production, but also the flexibility of devices for applying in flexible, scalable circuits to advance the development of future technology.

  19. DC diaphragm discharge in water solutions of selected organic acids

    Science.gov (United States)

    Vyhnankova, Edita J.; Hammer, Malte U.; Reuter, Stephan; Krcma, Frantisek

    2015-07-01

    Effect of four simple organic acids water solution on a DC diaphragm discharge was studied. Efficiency of the discharge was quantified by the hydrogen peroxide production determined by UV-VIS spectrometry of a H2O2 complex formed with specific titanium reagent. Automatic titration was used to study the pH behaviour after the plasma treatment. Optical emission spectroscopy overview spectra were recorded and detailed spectra of OH band and Hβ line were used to calculate the rotational temperature and comparison of the line profile (reflecting electron concentration) in the acid solutions. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  20. The Hydrophobic Effect.

    Science.gov (United States)

    Huque, Entazul M.

    1989-01-01

    Discusses the physical basis and current understanding of hydrophobic effects. The thermodynamic background of the effects, hydrophobic hydration, and hydrophobic interactions are described. Four existing controversies are outlined. (YP)

  1. Solution processed metal oxide thin film hole transport layers for high performance organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Steirer, K. Xerxes; Berry, Joseph J.; Chesin, Jordan P.; Lloyd, Matthew T.; Widjonarko, Nicodemus Edwin; Miedaner, Alexander; Curtis, Calvin J.; Ginley, David S.; Olson, Dana C.

    2017-01-10

    A method for the application of solution processed metal oxide hole transport layers in organic photovoltaic devices and related organic electronics devices is disclosed. The metal oxide may be derived from a metal-organic precursor enabling solution processing of an amorphous, p-type metal oxide. An organic photovoltaic device having solution processed, metal oxide, thin-film hole transport layer.

  2. Development of TLSER model and QSAR model for predicting partition coefficients of hydrophobic organic chemicals between low density polyethylene film and water.

    Science.gov (United States)

    Liu, Huihui; Wei, Mengbi; Yang, Xianhai; Yin, Cen; He, Xiao

    2017-01-01

    Partition coefficients are vital parameters for measuring accurately the chemicals concentrations by passive sampling devices. Given the wide use of low density polyethylene (LDPE) film in passive sampling, we developed a theoretical linear solvation energy relationship (TLSER) model and a quantitative structure-activity relationship (QSAR) model for the prediction of the partition coefficient of chemicals between LDPE and water (Kpew). For chemicals with the octanol-water partition coefficient (log Kow) coefficient (R(2)) and cross-validated coefficient (Q(2)). In order to further explore the theoretical mechanisms involved in the partition process, a QSAR model with four descriptors (MLOGP (Moriguchi octanol-water partition coeff.), P_VSA_s_3 (P_VSA-like on I-state, bin 3), Hy (hydrophilic factor) and NssO (number of atoms of type ssO)) was established, and statistical analysis indicated that the model had satisfactory goodness-of-fit, robustness and predictive ability. For chemicals with log KOW>8, a TLSER model with Vx and a QSAR model with MLOGP as descriptor were developed. This is the first paper to explore the models for highly hydrophobic chemicals. The applicability domain of the models, characterized by the Euclidean distance-based method and Williams plot, covered a large number of structurally diverse chemicals, which included nearly all the common hydrophobic organic compounds. Additionally, through mechanism interpretation, we explored the structural features those governing the partition behavior of chemicals between LDPE and water.

  3. The physical origin of hydrophobic effects

    Science.gov (United States)

    Sun, Qiang

    2017-03-01

    From the structural studies on water and air/water interface, hydration free energy is derived, and used to investigate the origin of hydrophobic effects. As a solute is dissolved into water, hydration free energy increases, and is divided into initial and hydrophobic solvation processes. In the initial process, hydration free energy is dominated by hydrogen bonding in interfacial water (topmost water layer at solute/water interface). For hydrophobic process, hydration free energy is related to the hydrogen bonding in bulk and interfacial water. Therefore, hydrophobic effects originate from the structural competition between hydrogen bonding in bulk water and that in interfacial water.

  4. Method for making nanoporous hydrophobic coatings

    Science.gov (United States)

    Fan, Hongyou; Sun, Zaicheng

    2013-04-23

    A simple coating method is used to form nanoporous hydrophobic films that can be used as optical coatings. The method uses evaporation-induced self-assembly of materials. The coating method starts with a homogeneous solution comprising a hydrophobic polymer and a surfactant polymer in a selective solvent. The solution is coated onto a substrate. The surfactant polymer forms micelles with the hydrophobic polymer residing in the particle core when the coating is dried. The surfactant polymer can be dissolved and selectively removed from the separated phases by washing with a polar solvent to form the nanoporous hydrophobic film.

  5. Cell-surface hydrophobicity of Staphylococcus saprophyticus.

    Science.gov (United States)

    Schneider, P. F.; Riley, T. V.

    1991-01-01

    The cell-surface hydrophobicity of 100 urinary isolates of Staphylococcus saprophyticus, cultured from symptomatic females in the general population, was assessed using a two-phase aqueous:hydrocarbon system. Relatively strong cell-surface hydrophobicity was exhibited by 79 isolates using the criteria employed, while only 2 of the remaining 21 isolates failed to demonstrate any detectable hydrophobicity. Cell-surface hydrophobicity may be a virulence factor of S. saprophyticus, important in adherence of the organism to uroepithelia. Additionally, the data support the concept that cell-surface hydrophobicity may be a useful predictor of clinical significance of coagulase-negative staphylococci isolated from clinical sources. PMID:1993454

  6. X-ray imaging sensor arrays on foil using solution processed organic photodiodes and organic transistors

    NARCIS (Netherlands)

    Kumar, A.; Moet, D.; Steen, J.L. van der; Tripathi, A.K.; Rodriguez, F.G.; Maas, J.; Simon, M.; Reutten, W.; Douglas, A.; Raaijmakers, R.; Malinowski, P.E.; Myny, K.; Shafique, U.; Andriessen, R.; Heremans, P.; Gelinck, G.H.

    2014-01-01

    We demonstrate organic imaging sensor arrays fabricated on flexible plastic foil with the solution processing route for both photodiodes and thin film transistors. We used the photovoltaic P3HT:PCBM blend for fabricating the photodiodes using spin coating and pentacene as semiconductor material for

  7. Micro-organization of humic acids in aqueous solutions

    Science.gov (United States)

    Klučáková, Martina; Věžníková, Kateřina

    2017-09-01

    The methods of dynamic light scattering and micro-rheology were used to investigate the molecular organization of humic acids in solutions. The obtained results were supplemented by ultraviolet/visible spectrometry and measurement of the zeta potential. Particle tracking micro-rheology was used for the first time as a novel method in humic research. Solutions of humic acids were prepared in three different mediums: NaOH, NaCl, and NaOH neutralized by HCl after dissolution of the humic sample. The molecular organization of humic acids was studied over a wide concentration range (0.01-10 g dm-3). Two breaks were detected in the obtained concentration dependencies. The rearrangements were observed at concentrations around 0.02 g dm-3 and 1 g dm-3. Changes in the measured values observed at around 0.02 g dm-3 were less noticeable and were related to the formation of particles between 100 and 1000 nm in size and the strong bimodal character of humic systems diluted by NaCl. The ;switch-over point; at around 1 g dm-3 indicated changes in the secondary structure of humic acids connected with the increase in colloidal stability (decrease of zeta potential), the decrease in polydispersity, and minimal values of viscosity.

  8. Adsorption and Separation of Aromatic Amino Acids from Aqueous Solutions Using Metal-Organic Frameworks.

    Science.gov (United States)

    Jonckheere, Dries; Steele, Julian A; Claes, Birgit; Bueken, Bart; Claes, Laurens; Lagrain, Bert; Roeffaers, Maarten B J; De Vos, Dirk E

    2017-09-06

    Metal-organic frameworks (MOFs) are investigated for the adsorption of aromatic amino acids l-phenylalanine (l-Phe), l-tryptophan (l-Trp), and l-tyrosine (l-Tyr) from aqueous solutions. After screening a range of water-stable MOFs, the hydrophobic Zr-MOF MIL-140C emerged as the best performing material, exhibiting uptakes of 15 wt % for l-Trp and 20 wt % for l-Phe. These uptakes are 5-10 wt % higher than those of large-pore zeolites Beta and Y. Both single-compound and competitive adsorption isotherms for l-Phe and l-Trp were experimentally obtained at the natural pH of these amino acid mixtures (pH 6.5-7) without additional pH modification. We find that the hydrophobic nature of MIL-140C and the capacity of l-Trp to form hydrogen bonds favor the uptake of l-Trp with its larger indole moiety compared to the smaller phenyl side group of l-Phe. On the basis of literature and vibrational analysis, observations of hydrogen-bonded l-Trp within the MIL-140C framework are evidenced by red- and blue-shifted -NH vibrations (3400 cm(-1)) in Fourier transform infrared spectroscopy, which were attributed to types N-Hl-Trp···πMIL-140C and N-Hl-Trp···OMIL-140C, respectively. MIL-140C is shown to be recycled at least three times for both aromatic amino acids without any loss of adsorption capacity, separation performance, or crystallinity. Desorption of aromatic amino acids proceeds easily in aqueous ethanol. Substantial coadsorption of negatively charged amino acids l-glutamate and l-aspartate (l-Glu and l-Asp) was observed from a model solution for wheat straw protein hydrolysate at pH 4.3. On the basis of these results, we conclude that MIL-140C is an interesting material for the recovery of essential aromatic amino acids l-Tyr, l-Phe, and l-Trp and of l-Glu and l-Asp from waste protein hydrolysates.

  9. Properties and Research Advances of Fluorine-containing Hydrophobic and Oleophobic Organics%含氟有机化合物的双疏特性及其研究进展

    Institute of Scientific and Technical Information of China (English)

    李丹; 王相承; 李江存; 鲁建英

    2014-01-01

    综述了具有双疏特性的有机氟化合物的物理化学性质,含氟有机化合物织物整理剂、有机聚合材料及表面改性的研究进展。%Ultra hydrophobicity and oleophobicity of chemical compound are widely used in water and oil resist-ance, corrosion and pollution prevention and self-cleaning materials. The synthesis and application of fluorine-con-taining hydrophobic and oleophobic organics have aroused much research interests in recent years. In this paper, the physical and chemical properties of fluorine -containing hydrophobic and oleophobic organics are summarized, re-search advances of fluorine-containing fishing agent, fluorine-containing polymer, surface modification with fluo-rine-containing organics are reviewed.

  10. When a solution is not a solution: Medicaid and Health Maintenance Organizations.

    Science.gov (United States)

    Spitz, B

    1979-01-01

    Health Maintenance Organization (HMOs) are repeatedly described as a general solution to the health care crisis and a specific solution to the problems confronting Medicare and Medicaid. The potential incorporation of HMOs into Medicaid has promised to improve the states' ability to accurately budget program expenditures, simplify management, eliminate abusive practices directly linked to fee-for-service (e.g., billing for undelivered services for providing unnecessary care) and, most important, contain costs. At the same time it has promised to increase access to mainstream medicine. Experience has shown, however, that the promise has often been severely compromised by unethical HMO marketing practices, inadequacy of services and excessive administrative costs. This article examines some of the reasons: the political process which created HMOs, the rhetorical claims which exaggerated the strengths of prepaid group practice and distorted the formulation of policy, and the peculiar characteristics of the Medicaid program which have caused Medicaid HMOs to deviate considerably from theoretical expectations.

  11. SOLVENT POLARITY AND INTERNAL STRESSES CONTROL THE SWELLING BEHAVIOUR OF GREEN WOOD DURING DEHYDRATION IN ORGANIC SOLUTION

    Directory of Open Access Journals (Sweden)

    Shanshan Chang,

    2012-04-01

    Full Text Available The dimensional variations of green wood samples induced by organic solvents have been studied. The solvents used (ethanol, isopropanol, acetone, and acetonitrile covered a wide range of polarity and were studied pure and in aqueous solutions over a wide range of concentrations. Samples of normal and tension wood of poplar were used in order to minimize the effect of hydrophobic extractives on the wood-solvent interactions. The evolution of wood volume and of tangential strain with the concentration of the organic solvents shows a behavior similar to gels, with a significant swelling for solutions of intermediate polarity. The similarity of volume obtained in water and less polar pure organic solvents strikingly contrasted the different effects of water and organic solvents on dry wood. Low-polarity solvents were extremely effective in the stress release of tension wood, as indicated by the pattern of longitudinal shrinkage. Solvent exchange does not affect the mesoporous structure of the cell walls of tension wood and is a promising way to reduce internal stress in wood products.

  12. Transfer of hydrophobic contaminants in urban runoff particles to benthic organisms estimated by an in vitro bioaccessibility test

    DEFF Research Database (Denmark)

    Nakajima, F.; Saito, K.; Isozaki, Y.

    2006-01-01

    An in vitro bioaccessibility test was applied for assessing the transfer of polycyclic aromatic hydrocarbons (PAHs) present in road dust, into benthic organisms living in a receiving water body. The road dust is supposed to be urban runoff particles under wet weather conditions. Sodium dodecyl...... concentration in the original dust. The PAH composition in benthic organisms (polychaetes) did not correspond with that of the surrounding sediment and the PAHs detected were also detected in high concentrations in the SDS extract of road dust. When testing the toxicity of the extracted contaminants...... the exposed contaminants than the traditional organic solvent extraction method and the SDS extracted fraction is applicable to toxicity tests reflecting the digestive process....

  13. Relative importance of microplastics as a pathway for the transfer of hydrophobic organic chemicals to marine life

    NARCIS (Netherlands)

    Bakir, A.; O'Connor, I.A.; Rowland, S.J.; Hendriks, A.J.; Thompson, R.C.

    2016-01-01

    It has been hypothesised that, if ingested, plastic debris could act as vector for the transfer of chemical contaminants from seawater to organisms, yet modelling suggest that, in the natural environment, chemical transfer would be negligible compared to other routes of uptake. However, to date, the

  14. Relative importance of microplastics as a pathway for the transfer of hydrophobic organic chemicals to marine life

    NARCIS (Netherlands)

    Bakir, A.; O'Connor, I.A.; Rowland, S.J.; Hendriks, A.J.; Thompson, R.C.

    2016-01-01

    It has been hypothesised that, if ingested, plastic debris could act as vector for the transfer of chemical contaminants from seawater to organisms, yet modelling suggest that, in the natural environment, chemical transfer would be negligible compared to other routes of uptake. However, to date, the

  15. A flow-through passive dosing system for continuously supplying aqueous solutions of hydrophobic chemicals to bioconcentration and aquatic toxicity tests

    DEFF Research Database (Denmark)

    Adolfsson-Erici, Margaretha; Åkerman, Gun; Jahnke, Annika

    2012-01-01

    A continuous supply of water with defined stable concentrations of hydrophobic chemicals is a requirement in a range of laboratory tests such as the OECD 305 protocol for determining the bioconcentration factor in fish. Satisfying this requirement continues to be a challenge, particularly for hyd...

  16. Enhanced super-hydrophobic and switching behavior of ZnO nanostructured surfaces prepared by simple solution--immersion successive ionic layer adsorption and reaction process.

    Science.gov (United States)

    Suresh Kumar, P; Sundaramurthy, J; Mangalaraj, D; Nataraj, D; Rajarathnam, D; Srinivasan, M P

    2011-11-01

    A simple and cost-effective successive ionic layer adsorption and reaction (SILAR) method was adopted to fabricate hydrophobic ZnO nanostructured surfaces on transparent indium-tin oxide (ITO), glass and polyethylene terephthalate (PET) substrates. ZnO films deposited on different substrates show hierarchical structures like spindle, flower and spherical shape with diameters ranging from 30 to 300 nm. The photo-induced switching behaviors of ZnO film surfaces between hydrophobic and hydrophilic states were examined by water contact angle and X-ray photoelectron spectroscopy (XPS) analysis. ZnO nanostructured films had contact angles of ~140° and 160°±2 on glass and PET substrates, respectively, exhibiting hydrophobic behavior without any surface modification or treatment. Upon exposure to ultraviolet (UV) illumination, the films showed hydrophilic behavior (contact angle: 15°±2), which upon low thermal stimuli revert back to its original hydrophobic nature. Such reversible and repeatable switching behaviors were observed upon cyclical exposure to ultraviolet radiation. These biomimetic ZnO surfaces exhibit good anti-reflective properties with lower reflectance of 9% for PET substrates. Thus, the present work is significant in terms of its potential application in switching devices, solar coatings and self-cleaning smart windows.

  17. Simultaneous estimation of glass-water distribution and PDMS-water partition coefficients of hydrophobic organic compounds using simple batch method.

    Science.gov (United States)

    Hsieh, Min-Kai; Fu, Chung-Te; Wu, Shian-chee

    2011-09-15

    A simple batch method by use of refilling and nonrefilling experimental procedures and headspace solid phase microextraction was applied to simultaneously obtain the glass-water distribution coefficients (K(GW)) and polydimethylsiloxane(PDMS)-water partition coefficients (K(PW)) of hydrophobic organic compounds (HOCs). The simple batch method takes into consideration the glass-surface bound HOCs and the corresponding equilibrium distribution of HOCs among the glass, water, headspace, and polydimethylsiloxane (PDMS). The K(PW) and K(GW) values of 53 PCB congeners were determined. The glass-bound fraction predominated over other fractions for highly chlorinated PCBs. Ignoring glass adsorption and assuming a complete mass balance could thus substantially underestimate the K(PW) for HOCs in traditional work. Good linear correlations of logα (the overall mass transfer rate constant) vs logK(PW), logK(PW) vs logK(OW), and logK(GW) vs logK(OW) were observed, with logα = -0.91 logK(PW) + 1.13, R(2) = 0.93; logK(PW) = 1.032 logK(OW) - 0.493, R(2) = 0.947; and logK(GW) = 0.93 logK(OW) - 2.30, R(2) = 0.90. The K(PW) values from this study were compared with those in the literature. With an account of the glass adsorption, the accuracy of the K(PW) determination and the estimation of the dissolved concentration in water for highly hydrophobic compounds can be significantly improved.

  18. Inorganic and Organic Solution-Processed Thin Film Devices

    Institute of Scientific and Technical Information of China (English)

    Morteza Eslamian

    2017-01-01

    Thin films and thin film devices have a ubiquitous presence in numerous conventional and emerging tech-nologies. This is because of the recent advances in nanotechnology, the development of functional and smart materials, conducting polymers, molecular semiconductors, carbon nanotubes, and graphene, and the employment of unique prop-erties of thin films and ultrathin films, such as high surface area, controlled nanostructure for effective charge transfer, and special physical and chemical properties, to develop new thin film devices. This paper is therefore intended to provide a concise critical review and research directions on most thin film devices, including thin film transistors, data storage memory, solar cells, organic light-emitting diodes, thermoelectric devices, smart materials, sensors, and actuators. The thin film devices may consist of organic, inorganic, and composite thin layers, and share similar functionality, properties, and fabrication routes. Therefore, due to the multidisciplinary nature of thin film devices, knowledge and advances already made in one area may be applicable to other similar areas. Owing to the importance of developing low-cost, scalable, and vacuum-free fabrication routes, this paper focuses on thin film devices that may be processed and deposited from solution.

  19. Solution-processed organic spin-charge converter.

    Science.gov (United States)

    Ando, Kazuya; Watanabe, Shun; Mooser, Sebastian; Saitoh, Eiji; Sirringhaus, Henning

    2013-07-01

    Conjugated polymers and small organic molecules are enabling new, flexible, large-area, low-cost optoelectronic devices, such as organic light-emitting diodes, transistors and solar cells. Owing to their exceptionally long spin lifetimes, these carbon-based materials could also have an important impact on spintronics, where carrier spins play a key role in transmitting, processing and storing information. However, to exploit this potential, a method for direct conversion of spin information into an electric signal is indispensable. Here we show that a pure spin current can be produced in a solution-processed conducting polymer by pumping spins through a ferromagnetic resonance in an adjacent magnetic insulator, and that this generates an electric voltage across the polymer film. We demonstrate that the experimental characteristics of the generated voltage are consistent with it being generated through an inverse spin Hall effect in the conducting polymer. In contrast with inorganic materials, the conducting polymer exhibits coexistence of high spin-current to charge-current conversion efficiency and long spin lifetimes. Our discovery opens a route for a new generation of molecular-structure-engineered spintronic devices, which could lead to important advances in plastic spintronics.

  20. Chemical characterization of the ambient organic aerosol soluble in water: 1. Isolation of hydrophobic and hydrophilic fractions with a XAD-8 resin

    Science.gov (United States)

    Sullivan, Amy P.; Weber, Rodney J.

    2006-03-01

    Group separation of the aqueous extract of fine particles bearing water-soluble organic carbon (WSOC) provides unique insights into the sources of organic carbon (OC). XAD-8 resin coupled with a Total Organic Carbon analyzer allows for direct quantification. We term the fraction of WSOC not retained by a XAD-8 resin column at pH 2 as hydrophilic WSOC (WSOCxp); this includes saccharides, amines, and carbonyls and aliphatic monocarboxylic/dicarboxylic/oxocarboxylic acids with less than 4 or 5 carbons. The fraction of WSOC retained by XAD-8, termed the hydrophobic fraction (WSOCxr), include aromatic acids, phenols, organic nitrates, cyclic acids, and carbonyls and monocarboxylic/dicarboxylic acids with greater than 3 or 4 carbons. However, only aromatic compounds (or aromatic-like compounds with similar properties) can subsequently be extracted from XAD-8 with high efficiency. By coupling a Particle-into-Liquid Sampler with this technique, online measurements of WSOC, WSOCxp, and WSOCxr are possible. Urban measurements from St. Louis and Atlanta, on a carbon mass basis, show an increase in the mean WSOC fraction from winter (51%) to summer (61%), due to increases in the WSOCxp/OC from 0.25 to 0.35. During a summer Atlanta PM event, WSOC to OC was 0.75, driven largely by increases in the WSOCxp. The results are consistent with the view that in the summer, there are increased amounts of oxygenated polar compounds, possibly from secondary organic aerosol production, and that these compounds account for an even larger fraction of OC during stagnation events. A companion paper describes a method to further group speciate these XAD-8 isolated fractions.

  1. The physical origin of hydrophobic effects

    CERN Document Server

    Sun, Qiang

    2016-01-01

    Because the strength of hydrogen bonding in water is stronger than that of van der Waals Interaction, water should play an important role in the process of hydrophobic effects. According to our recent structural studies on bulk water and air/water interface, the hydrophobic solutes mainly affect the structure of the topmost water layer (interfacial water) at solute/water interface. In reference with bulk water, due to truncations of hydrogen bonding at the interface, the effects of solutes on water structure are ascribed to the loss of tetrahedral hydrogen bonding in interfacial water. From this, the hydration free energy is derived, and utilized to investigate the dissolved behaviors of hydrophobic solutes. With increasing the size of solutes, this leads to the increase of hydration free energy, which can be divided into the initial solvation and hydrophobic solvation processes, respectively. In the initial solvation process, the hydration free energy is dominated by the hydrogen bonding in interfacial water...

  2. Selective isolation of bacteria from soil with hydrophobic materials

    OpenAIRE

    Oku, Shota; Nishiyama, Masaya; Takao, Yuji

    2011-01-01

    Bacterial strains having a hydrophobic cell surface have often been considered as degraders of hydrophobic organic pollutants in soil. In this study, bacterial strains were isolated using hydrophobic materials from 12 soil samples, and their cell surface hydrophobicity was determined by evaluating their adherence to n-hexane. Bacterial strains isolated using polytetrafluoroethylene (PTFE) membrane were more hydrophobic on an average than those isolated with styrene-divinylbenzene (DVB) partic...

  3. Mechanistic roles of soil humus and minerals in the sorption of nonionic organic compounds from aqueous and organic solutions

    Science.gov (United States)

    Chiou, C.T.; Shoup, T.D.; Porter, P.E.

    1985-01-01

    Mechanistic roles of soil humus and soil minerals and their contributions to soil sorption of nonionic organic compounds from aqueous and organic solutions are illustrated. Parathion and lindane are used as model solutes on two soils that differ greatly in their humic and mineral contents. In aqueous systems, observed sorptive characteristics suggest that solute partitioning into the soil-humic phase is the primary mechanism of soil uptake. By contrast, data obtained from organic solutions on dehydrated soil partitioning into humic phase and adsorption by soil minerals is influenced by the soil-moisture content and by the solvent medium from which the solute is sorbed. ?? 1985.

  4. Adhesion of bacterial pathogens to soil colloidal particles: influences of cell type, natural organic matter, and solution chemistry.

    Science.gov (United States)

    Zhao, Wenqiang; Walker, Sharon L; Huang, Qiaoyun; Cai, Peng

    2014-04-15

    Bacterial adhesion to granular soil particles is well studied; however, pathogen interactions with naturally occurring colloidal particles (organic matter (NOM), and solution chemistry. Specifically, batch adhesion experiments were conducted using NOM-present, NOM-stripped soil colloids, Streptococcus suis SC05 and Escherichia coli WH09 over a wide range of solution pH (4.0-9.0) and ionic strength (IS, 1-100 mM KCl). Cell characterization techniques, Freundlich isotherm, and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory (sphere-sphere model) were utilized to quantitatively determine the interactions between cells and colloids. The adhesion coefficients (Kf) of S. suis SC05 to NOM-present and NOM-stripped soil colloids were significantly higher than E. coli WH09, respectively. Similarly, Kf values of S. suis SC05 and E. coli WH09 adhesion to NOM-stripped soil colloids were greater than those colloids with NOM-present, respectively, suggesting NOM inhibits bacterial adhesion. Cell adhesion to soil colloids declined with increasing pH and enhanced with rising IS (1-50 mM). Interaction energy calculations indicate these adhesion trends can be explained by DLVO-type forces, with S. suis SC05 and E. coli WH09 being weakly adhered in shallow secondary energy minima via polymer bridging and charge heterogeneity. S. suis SC05 adhesion decreased at higher IS 100 mM, which is attributed to the change of hydrophobic effect and steric repulsion resulted from the greater presence of extracellular polymeric substances (EPS) on S. suis SC05 surface as compared to E. coli WH09. Hence, pathogen adhesion to the colloidal material is determined by a combination of DLVO, charge heterogeneity, hydrophobic and polymer interactions as a function of solution chemistry.

  5. Organic solid solution composed of two structurally similar porphyrins for organic solar cells.

    Science.gov (United States)

    Zhen, Yonggang; Tanaka, Hideyuki; Harano, Koji; Okada, Satoshi; Matsuo, Yutaka; Nakamura, Eiichi

    2015-02-18

    A solid solution of a 75:25 mixture of tetrabenzoporphyrin (BP) and dichloroacenaphtho[q]tribenzo[b,g,l]porphyrin (CABP) forms when they are generated in a matrix of (dimethyl(o-anisyl)silylmethyl)(dimethylphenylsilylmethyl)[60]fullerene. This solid solution provides structural and optoelectronic properties entirely different from those of either pristine compounds or a mixture at other blending ratios. The use of this BP:CABP solid solution for organic solar cell (OSC) devices resulted in a power conversion efficiency (PCE) value higher by 16 and 300% than the PCE values obtained for the devices using the single donor BP and CABP, respectively, in a planar heterojunction architecture. This increase originates largely from the increase in short circuit current density, and hence by enhanced charge carrier separation at the donor/acceptor interface, which was probably caused by suitable energy level for the solid solution state, where electronic coupling between the two porphyrins occurred. The results suggest that physical and chemical modulation in solid solution is beneficial as an operationally simple method to enhance OSC performance.

  6. Relative importance of microplastics as a pathway for the transfer of hydrophobic organic chemicals to marine life.

    Science.gov (United States)

    Bakir, Adil; O'Connor, Isabel A; Rowland, Steven J; Hendriks, A Jan; Thompson, Richard C

    2016-12-01

    It has been hypothesised that, if ingested, plastic debris could act as vector for the transfer of chemical contaminants from seawater to organisms, yet modelling suggest that, in the natural environment, chemical transfer would be negligible compared to other routes of uptake. However, to date, the models have not incorporated consideration of the role of gut surfactants, or the influence of pH or temperature on desorption, whilst experimental work has shown that these factors can enhance desorption of sorbed contaminants several fold. Here, we modelled the transfer of sorbed organic contaminants dichlorodiphenyltrichloroethane (DDT), phenanthrene (Phe) and bis-2-ethylhexyl phthalate (DEHP) from microscopic particles of polyvinylchloride (PVC) and polyethylene (PE) to a benthic invertebrate, a fish and a seabird using a one-compartment model OMEGA (Optimal Modelling for EcotoxicoloGical Applications) with different conditions of pH, temperature and gut surfactants. Environmental concentrations of contaminants at the bottom and the top of published ranges were considered, in combination with ingestion of either 1 or 5% by weight of plastic. For all organisms, the combined intake from food and water was the main route of exposure for Phe, DEHP and DDT with a negligible input from plastic. For the benthic invertebrate, predictions including the presence of contaminated plastic resulted in very small increases in the internal concentrations of DDT and DEHP, while the net change in the transfer of Phe was negligible. While there may be scenarios in which the presence of plastic makes a more important contribution, our modelling study suggests that ingestion of microplastic does not provide a quantitatively important additional pathway for the transfer of adsorbed chemicals from seawater to biota via the gut.

  7. Modelling the fate of hydrophobic organic contaminants in a boreal forest catchment: a cross disciplinary approach to assessing diffuse pollution to surface waters.

    Science.gov (United States)

    Bergknut, Magnus; Meijer, Sandra; Halsall, Crispin; Agren, Anneli; Laudon, Hjalmar; Köhler, Stephan; Jones, Kevin C; Tysklind, Mats; Wiberg, Karin

    2010-09-01

    The fate of hydrophobic organic compounds (HOCs) in soils and waters in a northern boreal catchment was explored through the development of a chemical fate model in a well-characterised catchment system dominated by two land types: forest and mire. Input was based solely on atmospheric deposition, dominated by accumulation in the winter snowpack. Release from soils was governed by the HOC concentration in soil, the soil organic carbon fraction and soil-water DOC content. The modelled export of selected HOCs in surface waters ranged between 11 and 250 ng day(-1) during the snow covered period, compared to 200 and 9600 ng/d during snow-melt; highlighting the importance of the snow pack as a source of these chemicals. The predicted levels of HOCs in surface water were in reasonable agreement to a limited set of measured values, although the model tended to over predict concentrations of HOCs for the forested sub-catchment, by over an order of magnitude in the case of hexachlorobenzene and PCB 180. This possibly reflects both the heterogeneity of the forest soils and the complicated and changing hydrology experienced between the different seasons.

  8. Review of methods and measurements of selected hydrophobic organic contaminant aqueous solubilities, vapor pressures, and air-water partition coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Bamford, H.A.; Baker, J.E.; Poster, D.L.

    1998-03-01

    Aqueous solubilities, vapor pressures, and Henry`s law constants for a wide range of organic contaminants of environmental interest are presented. Specifically, a discussion of methods used to measure these physical constants and resulting measurements are provided in an effort to examine the scope of physical constants reported in the scientific literature. Physical constants reviewed include those for 40 PAHs, 14 chlorinated aliphatics, 149 PCBs, 12 chlorinated benzenes, 16 dioxins, 63 furans, and 29 agrochemicals (a total of 323 compounds) and overall a total of 1,605 values are listed.

  9. Wrinkles and Folds of Activated Graphene Nanosheets as Fast and Efficient Adsorptive Sites for Hydrophobic Organic Contaminants.

    Science.gov (United States)

    Wang, Jun; Chen, Baoliang; Xing, Baoshan

    2016-04-01

    To create more wrinkles and folds as available adsorption sites, graphene nanosheets (GNS) were thermally treated with KOH for morphological alteration. The surface structures and properties of the activated graphene nanosheets (AGN) were characterized by BET-N2, SEM, TEM, Raman, XRD, XPS, and FTIR. After KOH etching, the highly crystal structure was altered, self-aggregation of graphene layers were evidently relieved, and more single to few layer graphene nanosheets were created with wrinkles and folds. Also both specific surface area and micropore volume of AGN increased relative to GNS. The adsorption of AGN toward p-nitrotoluene, naphthalene and phenanthrene were greatly enhanced in comparison with GNS, and gradually promoted with increasing degree of KOH etching. Adsorption rate of organic contaminants on AGN was very fast and efficient, whereas small molecules showed higher adsorption rates due to the more porous surface of graphene. In addition to π-π interaction, the high affinities of p-nitrotoluene to AGN are suggested from strong electron charge transfer interactions between nitro groups on p-nitrotoluene and defect sites of AGN. A positively linear correlation between organic molecule uptake and the micropore volume of AGN indicated that pore-filling mechanism may play an important role in adsorption. Morphological wrinkles and folds of graphene nanosheets can be regulated to enhance the adsorption capability and kinetics for efficient pollutant removal and to selectively preconcentrate adsorbates with different sizes for detection.

  10. Radiation-induced nitration of organic compounds in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Ershov, B.G.; Gordeev, A.V.; Bykov, G.L. [Russian Academy of Sciences, Moscow (Russian Federation). Frumkin Inst. of Physical Chemistry and Electrochemistry; Moisy, P. [CEA, Bagnols sur Ceze (France). Nuclear Energy Div.

    2012-07-01

    Radiolysis in aqueous nitrate and acetic acid solutions and nitrate/nitric acid and phenol was studied. The radiolysis of these solutes occurs with {sup circle} NO{sup 2} radical, which is the active nitrating agent. Accumulation of nitromethane and nitrite was determined during {gamma}-irradiation of aqueous solutions containing acetic and nitrate solutions. Irradiation of aqueous phenol-nitrate/nitric acid solutions results in the formation of 2- and 4-nitrophenols.

  11. A physiologically based toxicokinetic (PBTK) model for moderately hydrophobic organic chemicals in the European eel (Anguilla anguilla)

    Energy Technology Data Exchange (ETDEWEB)

    Brinkmann, Markus [Department of Ecosystem Analysis, Institute for Environmental Research, ABBt — Aachen Biology and Biotechnology, RWTH Aachen University, Aachen (Germany); Freese, Marko; Pohlmann, Jan-Dag; Kammann, Ulrike [Thünen Institute of Fisheries Ecology, Hamburg (Germany); Preuss, Thomas G. [Environmental Biology and Chemodynamics, Institute for Environmental Research, ABBt — Aachen Biology and Biotechnology, RWTH Aachen University, Aachen (Germany); Buchinger, Sebastian; Reifferscheid, Georg [Federal Institute of Hydrology (BFG), Department G3: Biochemistry, Ecotoxicology, Koblenz (Germany); Beiermeister, Anne; Hanel, Reinhold [Thünen Institute of Fisheries Ecology, Hamburg (Germany); Hollert, Henner, E-mail: Henner.hollert@bio5.rwth-aachen.de [Department of Ecosystem Analysis, Institute for Environmental Research, ABBt — Aachen Biology and Biotechnology, RWTH Aachen University, Aachen (Germany); State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing (China); College of Resources and Environmental Science, Chongqing University, Chongqing (China); Key Laboratory of Yangtze Water Environment, Ministry of Education, Tongji University, Shanghai 200092 (China)

    2015-12-01

    The European eel (Anguilla anguilla) is a facultatively catadromous fish species with a complex life cycle. Its current population status is alarming: recruitment has decreased drastically since the 1980s and its stock is still considered to be outside safe biological limits. Although there is no consensus on the reasons for this situation, it is currently thought to have resulted from a combination of different stressors, including anthropogenic contaminants. To deepen our understanding of the processes leading to the accumulation of lipophilic organic contaminants in yellow eels (i.e. the feeding, continental growth stage), we developed a physiologically based toxicokinetic model using our own data and values from the literature. Such models can predict the uptake and distribution of water-borne organic chemicals in the whole fish and in different tissues at any time during exposure. The predictive power of the model was tested against experimental data for six chemicals with n-octanol-water partitioning coefficient (log K{sub ow}) values ranging from 2.13–4.29. Model performance was excellent, with a root mean squared error of 0.28 log units. This model has the potential to help identify suitable habitats for restocking under eel management plans. - Highlights: • A PBTK model was developed for European eel (Anguilla anguilla). • Own experimental data and data from the literature were used for parameterization. • The predictive power of the model was excellent, with RMSE of 0.28 log units. • The developed model can be amended with sub-models for dietary and dermal exposure.

  12. An ultra-narrow linewidth solution-processed organic laser

    Institute of Scientific and Technical Information of China (English)

    Oussama Mhibik; Sebastien Forget; Dan Ott; George Venus; Ivan Divliansky; Leonid Glebov; Sebastien Chénais

    2016-01-01

    Optically pumped lasers based on solution-processed thin-film gain media have recently emerged as low-cost,broadly tunable,and versatile active photonics components that can fit any substrate and are useful for,e.g.,chemo-or biosensing or visible spectroscopy.Although single-mode operation has been demonstrated in various resonator architectures with a large variety of gain media--including dye-doped polymers,organic semiconductors,and,more recently,hybrid perovskites—the reported linewidths are typically on the order of a fraction of a nanometer or broader,i.e.,the coherence lengths are no longer than a few millimeters,which does not enable high-resolution spectroscopy or coherent sensing.The linewidth is fundamentally constrained by the short photon cavity lifetime in the standard resonator geometries.We demonstrate here a novel structure for an organic thin-film solid-state laser that is based on a vertical external cavity,wherein a holographic volume Bragg grating ensures beth spectral selection and output coupling in an otherwise very compact (~cm3) design.Under short-pulse (0.4 ns) pumping,Fourier-transform-limited laser pulses are obtained,with a full width at half-maximum linewidth of 900 MHz (1.25 pm).Using 20-ns-long pump pulses,the linewidth can be further reduced to 200 MHz (0.26 pm),which is four times above the Fourier limit and corresponds to an unprecedented coherence length of 1 m.The concept is potentially transferrable to any type of thin-film laser and can be ultimately made tunable;it also represents a very compact alternative to bulky grating systems in dye lasers.

  13. A new model for humic materials and their interactions with hydrophobic organic chemicals in soil-water or sediment-water systems

    Science.gov (United States)

    Wershaw, R. L.

    1986-01-01

    A generalized model of humic materials in soils and sediments, which is consistent with their observed properties, is presented. This model provides a means of understanding the interaction of hydrophobic pollutants with humic materials. In this model, it is proposed that the humic materials in soils and sediments consist of a number of different oligomers and simple compounds which result from the partial degradation of plant remains. These degradation products are stabilized by incorporation into humic aggregates bound together by weak bonding mechanisms, such as hydrogen bonding, pi bonding, and hydrophobic interactions. The resulting structures are similar to micelles or membranes, in which the interiors of the structures are hydrophobic and the exteriors are hydrophilic. Hydrophobic compounds will partition into the hydrophobic interiors of the humic micelles or "membrane-like" structures. ?? 1986.

  14. Geochemical processes and the effects of natural organic solutes on the solubility of selenium in coal-mine backfill samples from the Powder River basin, Wyoming

    Science.gov (United States)

    See, R.B.; Reddy, K.J.; Vance, G.F.; Fadlelmawla, A.A.; Blaylock, M.J.

    1995-01-01

    Geochemical processes and the effects of natural organic solutes on the solubility of selenium in coal-mine backfill aquifers were investigated. Backfill and ground-water samples were collected at coal mines in the Powder River Basin, Wyoming. Backfill was generally dominated by aluminum (14,400 to 49,000 mg/kg (milligrams per kilogram)), iron (3,330 to 23,200 mg/kg), and potassium (7,950 to 18,000 mg/kg). Backfill saturated-paste selenium concentrations ranged from 1 to 156 mg/kg (microsiemens per kilogram). Ground-water total selenium concentrations ranged from 3 to 125 mg/L. Dissolved organic carbon in all ground-water samples was dominated by hydrophobic and hydrophilic acids (38 to 84 percent). Selenite sorption/desorption experiments were conducted using background solutions of distilled-deionized water, 0.1 molar calcium chloride, and isolated hydrophobic and hydrophilic acids. Selenite sorption was larger when 0.1 molar calcium chloride was used. The addition of hydrophilic acid decreased selenite sorption more than the addition of hydrophobic acids. Geochemical modelling was used to predict the solid phases controlling dissolved selenium concentrations and to evaluate the effects of dissolved organic carbon on selenium solubility. Results suggested that 55 to 90 percent of selenium in backfill precipitation/dissolution extracts was dominated by magnesium selenate ion pairs. Dissolved organic carbon had little effect on selenium speciation. A redox chamber was constructed to control Eh and pH in water and backfill-core sample suspensions. The response of selenite and selenate in water samples to redox conditions did not follow thermodynamic predictions. Reduction of selenate in water samples did not occur at any of the redox levels tested.

  15. IMPLICATIONS OF MICROBIAL ADHESION TO HYDROCARBONS FOR EVALUATING CELL-SURFACE HYDROPHOBICITY .2. ADHESION MECHANISMS

    NARCIS (Netherlands)

    VANDERMEI, HC; VANDEBELTGRITTER, B; BUSSCHER, HJ

    1995-01-01

    Microbial adhesion to hydrocarbons (MATH) is generally considered to be a measure of the organisms cell surface hydrophobicity. Recent observations that the zeta potentials of hydrocarbons can be highly negative in the various solutions commonly used in MATH, have suggested that MATH may measure a

  16. Synthesis and characterization of hydrophobically modified polymeric betaines

    Directory of Open Access Journals (Sweden)

    Alexey Shakhvorostov

    2015-09-01

    Full Text Available Polymeric betaines containing long alkyl chains C12H25, C14H29, C16H33 and C18H37 were synthesized by Michael addition reaction of alkylaminocrotonates and methacrylic acid (MAA. They were characterized by FTIR, 13C NMR, DSC, DLS, GPC, cryo-TEM, viscometry and zeta-potential measurements. The polymers were fully soluble in DMF, THF and DMSO, partially dissolved in aromatic hydrocarbons (benzene, toluene, o-xylene and formed colloid solutions in aqueous KOH. In aqueous KOH and DMSO solutions, hydrophobically modified polymeric betaines behaved as polyelectrolytes. The average hydrodynamic size and zeta potential of diluted aqueous solutions of hydrophobic polybetainess containing dodecyl-, tetradecyl-, hexadecyl-, and octadecyl groups were studied as a function of pH. Anomalous low values of the isoelectric point (IEP of amphoteric macromolecules were found to be in the range of pH 2.7-3.4. According to DLS data, the average size of macromolecules tends to decrease with dilution. Zeta-potential of amphoteric macromolecules in aqueous solution is much higher than that in DMSO. The cryo-TEM results revealed that in both aqueous KOH and DMSO media, the micron- and nanosized vesicles existed. The structural organization of vesicles in water and DMSO is discussed. The wax inhibition effect of hydrophobic polybetaines at a decrease of the pour point temperatures of high paraffinic oils was better in comparison with commercial available ethylene-vinylacetate copolymers (EVA.

  17. Efficiency enhancement in solution processed organic and organic-inorganic perovskite solar cells

    Science.gov (United States)

    Xiao, Zhengguo

    Solution processed thin film photovoltaic devices are one of the most promising renewable energy sources. Organic solar cells have been intensively studied due to their advantages of light-weight, flexibility and low-cost materials and manufacturing. The organic-inorganic hybrid perovskite materials have recently shown great potential application in solar cells. The PCE increased dramatically from 3.8% in 2009 to a certified efficiency of 20.1% in 2014. In this dissertation, we focus on the efficiency enhancement for solution processed organic and organic-inorganic solar cells. In Chapter 2, I demonstrated that the crystallinity of the ferroelectric polymer P(VDF-TrFE) at the organic active layer/ electrode interface plays a critical role in the efficiency enhancement of organic solar cells. Then, The ferroelectric P(VDF-TrFE) nanocrystals was synthesized and successfully applied in the low band gap polymers. A high efficiency of 6.8% was achieved in the PCDTBT:PCBM system. Another small polar molecule, TPACA, was also applied to increase the efficiency of organic solar cells. In Chapter 3, I developed a universal approach of solvent fluxing to fabricate graded bulk heterojunction (BHJ) polymer:fullerene films to increase the device efficiency. The solvent fluxing process can extract part of the fullerene inside the BHJ film to the top surface to form graded BHJ. The PCE of the devices after solvent fluxing is increased by 15%--50% compared with the control devices without solvent fluxing. In Chapter 5, a two-step spin coating approach was developed to fabricate the continuous and compact organolead trihalide perovskite (OTP) films. The average PCE of methylammonium lead iodide (MAPbI3) perovskite devices reached 14.5% and 85% of the devices had efficiency above 14%. In Chapter 6, I discovered that the solvent annealing can be used to increase the grain size and crystallinity of the perovskite films. The highest device efficiency reached 15.6%, and device

  18. [Solute transport modeling application in groundwater organic contaminant source identification].

    Science.gov (United States)

    Wang, Shu-Fang; Wang, Li-Ya; Wang, Xiao-Hong; Lin, Pei; Liu, Jiu-Rong; Xin, Bao-Dong; He, Guo-Ping

    2012-03-01

    Investigation and numerical simulation, based on RT3D (reactive transport in 3-dimensions)were used to identify the source of tetrachloroethylene (PCE) and trichloroethylene (TCE) in the groundwater of a city in the north of China and reverse the input intensity. Multiple regressions were applied to analyze the influenced factors of input intensity of PCE and TCE using Stepwise function in Matlab. The results indicate that the factories and industries are the source of the PCE and TCE in groundwater. Natural attenuation was identified and the natural attenuation rates are 93.15%, 61.70% and 61.00% for PCE, and 70.05%, 73.66% and 63.66% for TCE in 173 days. The 4 source points identified by the simulation have released 0.910 6 kg PCE and 95.693 8 kg TCE during the simulation period. The regression analysis results indicate that local precipitation and the thickness of vadose zone are the main factors influencing organic solution transporting from surface to groundwater. The PCE and TCE concentration are found to be 0 and 5 mg x kg(-1) from surface to 35 cm in vadose zone. All above results suggest that PCE and TCE in groundwater are from the source in the surface. Natural attenuation occurred when PCE and TCE transporting from the surface to groundwater, and the rest was transported to groundwater through vadose zone. Local precipitation was one of the critical factors influencing the transportation of PCE and TCE to aquifer through sand, pebble and gravel of the Quaternary.

  19. Hydrophobic Solvation : A 2D IR Spectroscopic Inquest

    NARCIS (Netherlands)

    Bakulin, Artem A.; Liang, Chungwen; Jansen, Thomas La Cour; Wiersma, Douwe A.; Bakker, Huib J.; Pshenichnikov, Maxim S.

    2009-01-01

    For decades, the enigma of the hydrophobic force has captured the imagination of scientists. in particular, Frank and Evans' idea that the hydrophobic effect was mainly due to some kind of "iceberg" formation around a hydrophobic solute stimulated many experiments and molecular dynamics simulation s

  20. Structural and Mechanical Properties of Thin Films of Bovine Submaxillary Mucin versus Porcine Gastric Mucin on a Hydrophobic Surface in Aqueous Solutions

    DEFF Research Database (Denmark)

    Madsen, Jan Busk; Sotres, Javier; Pakkanen, Kirsi I.

    2016-01-01

    The structural and mechanical properties of thin films generated from two types of mucins, namely, bovine submaxillary mucin (BSM) and porcine gastric mucin (PGM) in aqueous environment were investigated with several bulk and surface analytical techniques. Both mucins generated hydrated films...... on hydrophobic polydimethylsiloxane (PDMS) surfaces from spontaneous adsorption arising from their amphiphilic characteristic. However, BSM formed more elastic films than PGM at neutral pH condition. This structural difference was manifested from the initial film formation processes to the responses to shear...... on a nonpolar PDMS surface leads to weakening of the mechanical integrity of the films....

  1. Oscillometric and conductometric analysis of aqueous and organic dosimeter solutions

    DEFF Research Database (Denmark)

    Kovacs, A.; Slezsak, I.; McLaughlin, W.L.

    1995-01-01

    Conductometric and oscillometric evaluation methods have earlier been developed to determine absorbed dose in the ethanol-monochlorobenzene dosimeter solution. Recent investigations on the same solution as well as on alanine solutions included the study of the possible use of different type...... ''conductometric'' electrodes and the study of the effect of frequency on the sensitivity of the method. On the basis of these investigations an oscillometric reader has been designed and tested. The same evaluation methods have been tested on the irradiated aqueous alanine solutions, aiming also at the study...... of the applicable concentration of the alanine solute and the dose (1 to 50 kGy) and dose-rate range using both electron (2.6 mu s at 13 mu A to 4 mu s at 1.0 A pulse length and beam current) and gamma radiation (0.13 to 30 kGy h(-1))....

  2. Comparison of two different passive air samplers (PUF-PAS versus SIP-PAS) to determine time-integrated average air concentration of volatile hydrophobic organic pollutants

    Science.gov (United States)

    Kim, Seung-Kyu; Park, Jong-Eun

    2014-06-01

    Despite remarkable achievements with r some chemicals, a field-measurement technique has not been advanced for volatile hydrophobic organic chemicals (HOCs) that are the subjects of international concern. This study assesses the applicability of passive air sampling (PAS) by comparing PUF-PAS and its modified SIP-PAS which was made by impregnating XAD-4 powder into PUF, overviewing the principles of PAS, screening sensitive parameters, and determining the uncertainty range of PAS-derived concentration. The PAS air sampling rate determined in this study, corrected by a co-deployed low-volume active air sampler (LAS) for neutral PFCs as model chemicals, was ˜1.2 m3 day-1. Our assessment shows that the improved sorption capacity in a SIP lengthens PAS deployment duration by expanding the linear uptake range and then enlarges the effective air sampling volume and detection frequency of chemicals at trace level. Consequently, volatile chemicals can be collected during sufficiently long times without reaching equilibrium when using SIP, while this is not possible for PUF. The most sensitive parameter to influence PAS-derived CA was an air-side mass transfer coefficient (kA), implying the necessity of spiking depuration chemicals (DCs) because this parameter is strongly related with meteorological conditions. Uncertainty in partition coefficients (KPSM-A or KOA) influences PAS-derived CA to a greater extent with regard to lower KPSM-A chemicals. Also, the PAS-derived CA has an uncertainty range of a half level to a 3-fold higher level of the calculated one. This work is expected to establish solid grounds for the improvement of field measurement technique of HOCs.

  3. Effect of University of Wisconsin organ-preservation solution on haemorheology

    NARCIS (Netherlands)

    van der Plaats, A; 't Hart, NA; Morariu, AM; Verkerke, GJ; Leuvenink, HGD; Ploeg, RJ; Rakhorst, G

    2004-01-01

    In conventional cold-storage organ preservation, the donor organ is flushed with University of Wisconsin (UW) solution at 0-4degreesC. The initial flush is used to wash out blood from the microcirculation to allow optimal preservation with the UW solution. The component hydroxyethyl starch (HES) of

  4. Xenotransplantation: A Potential Solution to the Critical Organ Donor Shortage

    Directory of Open Access Journals (Sweden)

    K Howe Sim

    1999-01-01

    Full Text Available The success of allotransplantation as a treatment for end-stage organ failure has resulted in the need for an increasing number of organ donors. Attempts to meet this need include the use of organs from living related and unrelated donors, financial or other incentives for the donor family, and even the reuse of transplanted organs. Despite these initiatives, the supply of organs for transplantation still falls far short of the demand, as evidenced by longer waiting times for transplantation and decreasing transplantation rates. Even if Canada were able to increase its organ donor rate to that of Spain (40 to 50/million, where organ donation is governed by ‘presumed consent’ legislation, this would not alleviate the problem of donor shortage. Interest in xenotransplantation stems from the need to overcome this increasingly severe shortage of human organs. Indeed, some argue that xenotransplantation is the only potential way of addressing this shortage. As immunological barriers to xenotransplantation are better understood, those hurdles are being addressed through genetic engineering of donor animals and the development of new drug therapies. However, before xenotransplantation can be fully implemented, both the scientific/medical communities and the general public must seriously consider and attempt to resolve the many complex ethical, social and economic issues that it presents.

  5. Nanoparticle flotation collectors II: the role of nanoparticle hydrophobicity.

    Science.gov (United States)

    Yang, Songtao; Pelton, Robert

    2011-09-20

    The ability of polystyrene nanoparticles to facilitate the froth flotation of glass beads was correlated to the hydrophobicity of the nanoparticles. Contact angle measurements were used to probe the hydrophobicity of hydrophilic glass surfaces decorated with hydrophobic nanoparticles. Both sessile water drop advancing angles, θ(a), and attached air bubble receding angle measurements, θ(r), were performed. For glass surfaces saturated with adsorbed nanoparticles, flotation recovery, a measure of flotation efficiency, increased with increasing values of each type of contact angle. As expected, the advancing water contact angle on nanoparticle-decorated, dry glass surfaces increased with surface coverage, the area fraction of glass covered with nanoparticles. However, the nanoparticles were far more effective at raising the contact angle than the Cassie-Baxter prediction, suggesting that with higher nanoparticle coverages the water did not completely wet the glass surfaces between the nanoparticles. A series of polystyrene nanoparticles was prepared to cover a range of surface energies. Water contact angle measurements, θ(np), on smooth polymer films formed from organic solutions of dissolved nanoparticles were used to rank the nanoparticles in terms of hydrophobicity. Glass spheres were saturated with adsorbed nanoparticles and were isolated by flotation. The minimum nanoparticle water contact angle to give high flotation recovery was in the range of 51° < θ(np(min)) ≤ 85°.

  6. Preparation of hydrophobic coatings

    Science.gov (United States)

    Branson, Eric D.; Shah, Pratik B.; Singh, Seema; Brinker, C. Jeffrey

    2009-02-03

    A method for preparing a hydrophobic coating by preparing a precursor sol comprising a metal alkoxide, a solvent, a basic catalyst, a fluoroalkyl compound and water, depositing the precursor sol as a film onto a surface, such as a substrate or a pipe, heating, the film and exposing the film to a hydrophobic silane compound to form a hydrophobic coating with a contact angle greater than approximately 150.degree.. The contact angle of the film can be controlled by exposure to ultraviolet radiation to reduce the contact angle and subsequent exposure to a hydrophobic silane compound to increase the contact angle.

  7. X-ray imaging sensor arrays on foil using solution processed organic photodiodes and organic transistors

    Science.gov (United States)

    Kumar, Abhishek; Moet, Date; van der Steen, Jan-Laurens; Tripathi, Ashutosh; Rodriguez, Francisco G.; Maas, Joris; Simon, Matthias; Reutten, Walter; Douglas, Alexander; Raaijmakers, Rob; Malinowski, Pawel E.; Myny, Kris; Shafique, Umar; Andriessen, Ronn; Heremans, Paul; Gelinck, Gerwin

    2014-05-01

    We demonstrate organic imaging sensor arrays fabricated on flexible plastic foil with the solution processing route for both photodiodes and thin film transistors. We used the photovoltaic P3HT:PCBM blend for fabricating the photodiodes using spin coating and pentacene as semiconductor material for the TFTs. Photodiodes fabricated with P3HT:PCBM absorb in the green part of the visible spectrum which matches with the typical scintillator output wavelength. The arrays consist of 32x32 pixels with variation in pixel resolution of 200μmx200μm, 300μmx300μm and of 1mmx1mm. The accurate reproducibility of shadow images of the objects demonstrates the potential of these arrays for imaging purposes. We also demonstrate that the crosstalk is relatively insignificant despite the fact that the active photodiode forms a continuous layer in the array. Since both photodiodes and TFTs are made of organic material, they are processed at low temperatures below 150°C on foil which means that these imaging sensors can be flexible, light weight and low cost when compared to conventional amorphous silicon based imaging sensors on rigid substrates. In combination with a scintillator on top of the arrays, we show the potential of these arrays for the X-ray imaging applications.

  8. The search for reliable aqueous solubility (Sw) and octanol-water partition coefficient (Kow) data for hydrophobic organic compounds; DDT and DDE as a case study

    Science.gov (United States)

    Pontolillo, James; Eganhouse, R.P.

    2001-01-01

    quality, the reliability of the DDT/ DDE Sw and Kow database is questionable. The nature and extent of the errors documented in this study are probably indicative of a more general problem in the literature of hydrophobic organic compounds. Under these circumstances, estimation of critical environmental parameters on the basis of Sw and Kow (for example, bioconcentration factors, equilibrium partition coefficients) is inadvisable because it will likely lead to incorrect environmental risk assessments. The current state of the database indicates that much greater efforts are needed to: 1) halt the proliferation of erroneous data and references, 2) initiate a coordinated program to develop improved methods of property determination, 3) establish and maintain consistent reporting requirements for physico-chemical property data, and 4) create a mechanism for archiving reliable data for widespread use in the scientific/regulatory community.

  9. Novel hydrophobically associative polyacrylamide with tunable viscosity

    Institute of Scientific and Technical Information of China (English)

    Xu Feng Zhang; Wen Hui Wu

    2009-01-01

    Hydrophobically associative polyacrylamide (HAPAM) were prepared in aqueous solution by radical copolymerization of novel cationic surface-active monomer, dimethylhexadecyl(3-acrylamidopropyl)ammonium bromide (DMHAB), with acrylarnide (AM) in the presence of DMHAB/CTAB mixed micelles. The length of hydrophobic microblock (N_H) in HAPAM is controlled by the molar fraction of DMHAB in mixed micelles, which can be mediated by the ratio of CTAB to DMHAB. The results of steady-state fluorescence probe and viscometry experiments showed the ability of HAPAM association was determined by the length of the hydrophobic microblock. HAPAM with tunable association ability are promising materials for thickening agent.

  10. Solution-Processable Organic Molecule for High-Performance Organic Solar Cells with Low Acceptor Content.

    Science.gov (United States)

    Wang, Kun; Guo, Bing; Xu, Zhuo; Guo, Xia; Zhang, Maojie; Li, Yongfang

    2015-11-11

    A new planar D2-A-D1-A-D2 structured organic molecule with bithienyl benzodithiophene (BDT) as central donor unit D1 and fluorine-substituted benzothiadiazole (BTF) as acceptor unit and alkyl-dithiophene as end group and donor unit D2, BDT-BTF, was designed and synthesized for the application as donor material in organic solar cells (OSCs). BDT-BTF shows a broad absorption in visible region, suitable highest occupied molecular orbital energy level of -5.20 eV, and high hole mobility of 1.07 × 10(-2) cm(2)/(V s), benefitted from its high coplanarity and strong crystallinity. The OSCs based on BDT-BTF as donor (D) and PC71BM as acceptor (A) at a D/A weight ratio of 3:1 without any extra treatment exhibit high photovoltaic performance with Voc of 0.85 V, Jsc of 10.48 mA/cm(2), FF of 0.66, and PCE of 5.88%. The morphological study by transmission electron microscopy reveals that the blend of BDT-BTF and PC71BM (3:1, w/w) possesses an appropriate interpenetrating D/A network for the exciton separation and charge carrier transport, which agrees well with the good device performance. The optimized D/A weight ratio of 3:1 is the lowest acceptor content in the active layer reported so far for the high-performance OSCs, and the organic molecules with the molecular structure like BDT-BTF could be promising high-performance donor materials in solution-processable OSCs.

  11. Determination of the cis-trans isomerization barriers of L-alanyl-L-proline in aqueous solutions and at water/hydrophobic interfaces by on-line temperature-jump relaxation HPLC and dynamic on-column reaction HPLC.

    Science.gov (United States)

    Shibukawa, Masami; Miyake, Ayaka; Eda, Sayaka; Saito, Shingo

    2015-09-15

    Proline cis-trans isomerization is known to play a key role in the rate-determining steps of protein folding. It is thus very important to understand the influence of environments, not only bulk solutions but also microenvironments such as interfaces, on the isomerization reaction of proline peptides. Here we present two HPLC methods for measurements of kinetic and equilibrium parameters for the isomerization reactions in bulk solutions and at liquid/solid interfaces. On-line temperature-jump relaxation HPLC (T-jump HPLC) allows the determination of forward and reverse rate constants of the isomerization in a bulk solution by monitoring the whole time course of conversion of pure isomers from both sides of the reaction, in contrast to other HPLC and capillary zone electrophoresis as well as spectrometric and calorimetric methods, which use a mixture of the isomers. We can then determine cis-trans isomerization barriers of the peptide at liquid/solid interfaces from the kinetic data obtained by dynamic on-column reaction HPLC and T-jump HPLC. We observed that the interconversion around the peptide bond for l-alanyl-l-proline (Ala-Pro) in water is accelerated at the surfaces of an alkyl-bonded silica and a poly(styrene-divinylbenzene) copolymer resin, and this is caused by a remarkable decrease in the enthalpy of activation. The molecular structures of the cis and trans forms of Ala-Pro estimated by quantum mechanics calculation reveal that an equilibrium shift toward the cis form as well as the rapid isomerization of Ala-Pro at the water/hydrophobic interfaces can be attributed to the lower polarity of the interfacial water at the surfaces of the hydrophobic materials compared to that of bulk water.

  12. Hydrophobic interactions increase attachment of gum Arabic- and PVP-coated Ag nanoparticles to hydrophobic surfaces.

    Science.gov (United States)

    Song, Jee Eun; Phenrat, Tanapon; Marinakos, Stella; Xiao, Yao; Liu, Jie; Wiesner, Mark R; Tilton, Robert D; Lowry, Gregory V

    2011-07-15

    A fundamental understanding of attachment of surface-coated nanoparticles (NPs) is essential to predict the distribution and potential risks of NPs in the environment. Column deposition studies were used to examine the effect of surface-coating hydrophobicity on NP attachment to collector surfaces in mixtures with varying ratios of octadecylichlorosilane (OTS)-coated (hydrophobic) glass beads and clean silica (hydrophilic) glass beads. Silver nanoparticles (AgNPs) coated with organic coatings of varying hydrophobicity, including citrate, polyvinylpyrrolidone (PVP), and gum arabic (GA), were used. The attachment efficiencies of GA and PVP AgNPs increased by 2- and 4-fold, respectively, for OTS-coated glass beads compared to clean glass beads. Citrate AgNPs showed no substantial change in attachment efficiency for hydrophobic compared to hydrophilic surfaces. The attachment efficiency of PVP-, GA-, and citrate-coated AgNPs to hydrophobic collector surfaces correlated with the relative hydrophobicity of the coatings. The differences in the observed attachment efficiencies among AgNPs could not be explained by classical DLVO, suggesting that hydrophobic interactions between AgNPs and OTS-coated glass beads were responsible for the increase in attachment of surface-coated AgNPs with greater hydrophobicity. This study indicates that the overall attachment efficiency of AgNPs will be influenced by the hydrophobicity of the NP coating and the fraction of hydrophobic surfaces in the environment.

  13. Structural and thermodynamic aspects of the hydrophobic effect.

    Science.gov (United States)

    Soda, K

    1993-01-01

    From analyses of the solvation structure around HS solutes for HS solvents and various water models by the RISM integral equation method, the following conclusions are drawn: 1) Water has more small cavities than HS solvents, which makes it easier for water to accommodate small solutes with a radius less than about 1A. 2) With increasing solute radius from 0 to 3A, the average orientation of hydrating water varies from an inward to an outward orientation, which shows that some reorganization of water occurs in response to the change in solute size. 3) The hydration structure is formed as a network structure due to H-bonding interactions between water molecules being supported by the cooperation of repulsive forces between solute and water. Repulsive interactions of not only O atoms but also H atoms with solute are essential to the formation of such hydration structure. With regard to the physical mechanism of the hydrophobic effect, the following is concluded from an analysis of the physical meaning of the basic formula for the free energy of cavity formation: 4) It is predicted from the scaled particle theory that the solvent exclusion effect caused by the introduction of solute into solvent is an important factor of the hydrophobic effect. 5) The large negative transfer entropy at room temperature characteristic of the hydrophobic hydration results primarily from the decrease in the configuration entropy of water due to the solvent exclusion effect. 6) The structuralization of hydrating water results in exactly compensating changes in enthalpy and entropy, and a large positive change in heat capacity. As a result, the hydrophobic effect is dominated by the entropy effect at room temperature, while it is driven by enthalpy at temperatures higher than 110 degrees C. 7) Hydrating water is energetically similar to bulk water, and the term "highly structured" is not appropriate to describe it. The following descriptions can be made on estimating the free energy of

  14. Organ trafficking: global solutions for a global problem.

    Science.gov (United States)

    Jafar, Tazeen H

    2009-12-01

    The organ trafficking market is on the rise worldwide. Numerous unfortunate stories of networks of brokers, physicians, and hospitals engaged in illegal trade have been featured in high-profile media. The profitable enterprises facilitating these unregulated services exploit the poor in underresourced countries and offer substandard medical care with unacceptable outcomes to the rich recipients. Despite efforts to boost altruistic organ donation and resolutions to curb transplant tourism, their implementation has been compromised. At the same time, the worldwide escalation in the number of patients with kidney failure coupled with a shortage in the supply of organs continues to fuel this trade. Thus, measures to enhance the donor pool in well-resourced countries to meet their own needs will act as a strong deterrent to the proliferation of transplant tourism in impoverished nations. Regulated schemes that include reimbursement for removing potential disincentives to organ donation and ensure the long-term safety of donors and their families are likely to increase living donations. Such socially responsible programs should be tested in both developed and developing countries for their own populations. It also is vital that developing countries establish a regulated, standardized, and ethical system of organ procurement; create awareness in physicians and the public; upgrade facilities and standardize medical care; and enforce legislation for transplantation. The World Health Organization, National Kidney Foundation, and international transplant and nephrology societies can have an instrumental role in facilitating initiatives in these critical areas. There should be clearly defined codes of conduct for health care facilities and professionals' roles in unregulated paid organ donations and transplants. Ultimately, physicians and transplant surgeons have the responsibility to ensure to the best of their ability that the organs they transplant were obtained upholding

  15. Decomposition Technology Development of Organic Component in a Decontamination Waste Solution

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Chong Hun; Oh, W. Z.; Won, H. J.; Choi, W. K.; Kim, G. N.; Moon, J. K

    2007-11-15

    Through the project of 'Decomposition Technology Development of Organic Component in a Decontamination Waste Solution', the followings were studied. 1. Investigation of decontamination characteristics of chemical decontamination process 2. Analysis of COD, ferrous ion concentration, hydrogen peroxide concentration 3. Decomposition tests of hardly decomposable organic compounds 4. Improvement of organic acid decomposition process by ultrasonic wave and UV light 5. Optimization of decomposition process using a surrogate decontamination waste solution.

  16. Hydrophobic effect at aqueous interfaces

    Science.gov (United States)

    Pohorille, Andrew

    2005-01-01

    Conceptual basis for hydrophobic effects in bulk water and at aqueous interfaces have similar conceptual basis but often manifests itself differently. Using a wide range of computer simulations as the basis, I will review different forms of hydrophobic effects at a variety of interfaces starting from simple liquid-vapor and water-oil interfaces and progressing to water-membrane interfaces. I will start with discussing how water is organized at different interfaces, stressing both similarities and differences. The main thread is that, as in the bulk liquid, hydrophobic effects have profound influence on conformational equilibria and organization of both small molecules and macromolecules, but the result of this influence is quite different. Specifically, it will be shown that many small, but not necessarily amphiphilic molecules tend to accumulate at the interface and, and this tendency will be explained. Furthermore, I will show that many short peptides that are disordered in water spontaneously fold into well-defined structures in the interfacial environment. Biological implications of this self-organizing effect will be discussed.

  17. Prediction of coal hydrophobicity

    Energy Technology Data Exchange (ETDEWEB)

    Labuschagne, B.C.J. [Council for Scientific and Industrial Research, Pretoria (South Africa). Div. of Energy Technology; Wheelock, T.D.; Guo, R.K.; David, H.T. [Iowa State Univ. of Science and Technology, Ames, IA (United States); Markuszewski, R. [Ames Lab., IA (United States)

    1988-12-31

    Many coals exhibit a certain degree of native hydrophobicity. The more hydrophobic coals (the higher-rank coals) are easily beneficiated by froth flotation or oil agglomeration, while the more hydrophilic coals (the lower-rank coals) are floated or agglomerated with difficulty. Coals of different ranks and often even of the same rank sometimes differ greatly in hydrophobicity as measured by contact angle or natural floatability. Although the degree of hydrophobicity of a coal is related to its rank and has been correlated with other surface properties of the coal , the known information is still not sufficient to allow a good estimation to be made of the hydrophobicity of a given coal and does not explain the variation of coal hydrophobicity as a function of rank. A statistical analysis of previously published data, as well as newly acquired data, shows that coal hydrophobicity correlates better with moisture content than with carbon content, and better with the moisture/carbon molar ratio than with the hydrogen/carbon or oxygen/carbon atomic ratios. These findings indicate that there is a strong association between hydrophobicity and coal moisture content.

  18. Aggregation in Organic Solutions of Malonamides: Consequences for Water Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Meridiano, Y.; Berthon, L.; Crozes, X.; Sorel, C. [CEA ValRho, DEN DRCP SCPS LCSE, F-30207 Bagnols Sur Ceze, (France); Dannus, P. [CEA Saclay, INSTN UEIN, F-91191 Gif Sur Yvette, (France); Antonio, M.R.; Chiarizia, R. [Argonne Natl Lab, CSE Div, Argonne, IL 60439 (United States); Zemb, T. [CEA CNRS UM2 ENSCM, Inst Chin Separat Marcoule, Bagnols Sur Ceze, (France)

    2009-07-01

    The molecular organization of N, N'-dimethyl-N, N'-dioctyl-hexyl-ethoxy-malonamide (DMDOHEMA), the current reference extractant for the DIAMEX (Diamide Extraction) process, is correlated with its water extraction properties from neutral media. The aggregation of DMDOHEMA in n-heptane was investigated by vapor pressure osmometry (VPO) and the aggregate speciation characterized by combined small-angle neutron and X-ray scattering (SANS and SAXS, respectively). Two approaches were taken to model the aggregation of the diamide and the water extraction as a function of the diamide concentration by taking into account a single aggregation equilibrium with an average aggregation number N equal to 4.28 {+-} 0.05; and a competition between two types of aggregates in the organic phase, namely, aggregates of the reverse micelle type with 4 diamides per aggregate, and an oligomeric structure composed of about 10 diamide molecules which appears at high extractant concentration ({>=} 1 mol/L). In both cases, the supramolecular speciation representing the monomers/aggregates distribution was determined, and for each supramolecular organization, a solubilization parameter was calculated using the Sergievskii-Dannus relationship. Thus, the correlation between the two types of micellization of the diamide and the extraction of water into the organic phase was demonstrated. The larger aggregates can extract about five times more water than monomers. (authors)

  19. Statistical analyses of hydrophobic interactions: A mini-review

    CERN Document Server

    Pratt, L R; Rempe, Susan B

    2016-01-01

    This review focuses on the striking recent progress in solving for hydrophobic interactions between small inert molecules. We discuss several new understandings. Firstly, the _inverse _temperature phenomenology of hydrophobic interactions, _i.e., strengthening of hydrophobic bonds with increasing temperature, is decisively exhibited by hydrophobic interactions between atomic-scale hard sphere solutes in water. Secondly, inclusion of attractive interactions associated with atomic-size hydrophobic reference cases leads to substantial, non-trivial corrections to reference results for purely repulsive solutes. Hydrophobic bonds are _weakened by adding solute dispersion forces to treatment of reference cases. The classic statistical mechanical theory for those corrections is not accurate in this application, but molecular quasi-chemical theory shows promise. Finally, because of the masking roles of excluded volume and attractive interactions, comparisons that do not discriminate the different possibilities face an...

  20. Acrylamide-b-N-isopropylacrylamide block copolymers : Synthesis by atomic transfer radical polymerization in water and the effect of the hydrophilic-hydrophobic ratio on the solution properties

    NARCIS (Netherlands)

    Wever, Diego Armando Z.; Ramalho, Graham; Picchioni, Francesco; Broekhuis, Antonius Augustinus

    2014-01-01

    A series of block copolymers of acrylamide and N-isopropylacrylamide (NIPAM) characterized by different ratios between the length of the two blocks have been prepared through atomic transfer radical polymerization in water at room temperature. The solution properties of the block copolymers were cor

  1. On the thermodynamics and kinetics of hydrophobic interactions at interfaces.

    Science.gov (United States)

    Vembanur, Srivathsan; Patel, Amish J; Sarupria, Sapna; Garde, Shekhar

    2013-09-05

    We have studied how primitive hydrophobic interactions between two or more small nonpolar solutes are affected by the presence of surfaces. We show that the desolvation barriers present in the potential of mean force between the solutes in bulk water are significantly reduced near an extended hydrophobic surface. Correspondingly, the kinetics of hydrophobic contact formation and breakage are faster near a hydrophobic surface than near a hydrophilic surface or in the bulk. We propose that the reduction in the desolvation barrier is a consequence of the fact that water near extended hydrophobic surfaces is akin to that at a liquid-vapor interface and is easily displaced. We support this proposal with three independent observations. First, when small hydrophobic solutes are brought near a hydrophobic surface, they induce local dewetting, thereby facilitating the reduction of desolvation barriers. Second, our results and those of Patel et al. (Proc. Natl. Acad. Sci. U.S.A. 2011, 108, 17678-17683) show that, whereas the association of small solutes in bulk water is driven by entropy, that near hydrophobic surfaces is driven by enthalpy, suggesting that the physics of interface deformation is important. Third, moving water away from its vapor-liquid coexistence, by applying hydrostatic pressure, leads to recovery of bulklike signatures (e.g., the presence of a desolvation barrier and an entropic driving force) in the association of solutes. These observations for simple solutes also translate to end-to-end contact formation in a model peptide with hydrophobic end groups, for which lowering of the desolvation barrier and acceleration of contact formation are observed near a hydrophobic surface. Our results suggest that extended hydrophobic surfaces, such as air-water or hydrocarbon-water surfaces, could serve as excellent platforms for catalyzing hydrophobically driven assembly.

  2. Solution processable organic/inorganic hybrid ultraviolet photovoltaic detector

    Directory of Open Access Journals (Sweden)

    Xiaopeng Guo

    2016-05-01

    Full Text Available Ultraviolet (UV photodetector is a kind of important optoelectronic device which can be widely used in scientific and engineering fields including astronomical research, environmental monitoring, forest-fire prevention, medical analysis, and missile approach warning etc. The development of UV detector is hindered by the acquirement of stable p-type materials, which makes it difficult to realize large array, low-power consumption UV focal plane array (FPA detector. Here, we provide a novel structure (Al/Poly(9,9-di-n-octylfuorenyl-2,7-diyl(PFO/ZnO/ITO to demonstrate the UV photovoltaic (PV response. A rather smooth surface (RMS roughness: 0.28 nm may be reached by solution process, which sheds light on the development of large-array, light-weight and low-cost UV FPA detectors.

  3. Solution mechanism guide: implementing innovation within a research & development organization.

    Science.gov (United States)

    Keeton, Kathryn E; Richard, Elizabeth E; Davis, Jeffrey R

    2014-10-01

    In order to create a culture more open to novel problem-solving mechanisms, NASA's Human Health and Performance Directorate (HH&P) created a strategic knowledge management tool that educates employees about innovative problem-solving techniques, the Solution Mechanism Guide (SMG). The SMG is a web-based, interactive guide that leverages existing and innovative problem-solving methods and presents this information as a unique user experience so that the employee is empowered to make the best decision about which problem-solving tool best meets their needs. By integrating new and innovative methods with existing problem solving tools, the SMG seamlessly introduces open innovation and collaboration concepts within HH&P to more effectively address human health and performance risks. This commentary reviews the path of creating a more open and innovative culture within HH&P and the process and development steps that were taken to develop the SMG.

  4. Kinetics of self-organization of polyampholyte nanoparticles in solutions

    Indian Academy of Sciences (India)

    H B Bohidar

    2008-06-01

    An appropriate composition of a binary solvent, water-ethanol, provides the necessary thermodynamic environment for the polyampholyte (gelatin) molecules to form self-assembled nano-clusters having fractal dimension, ≈ 2.6, in the bulk (3-D). The aggregation in the bulk of the solution appears to be an anomalous process and could be explained through Smoluchowski aggregation model. It gives a diffusion limited aggregation (DLA) type fractal dimension to the cluster in bulk, but shows extremely low polydispersity, which in fact is a signature of a slowly growing reaction limited cluster aggregation (RLA) process. Experimental results obtained from light scattering and electrophoresis experiments enable us to probe the kinetics of such growth processes.

  5. Effect of organic substrates on available elemental contents in nutrient solution

    Energy Technology Data Exchange (ETDEWEB)

    Ao, Y.S.; Sun, M.; Li, Y.Q. [Shanghai Jiao Tong University, Shanghai (China). School for Agriculture & Biology

    2008-07-15

    In this paper, the changes of available elemental contents in the nutrient solution extracts of organic substrates (peat moss, charred rice husk, chicken manure, sawdust, turfgrass clipping and weathered coal) were studied and compared with that in the water extracts. Results showed that available elemental contents in the nutrient solution extracts are significantly different between organic substrates, whereas ionic concentrations are basically under steady condition after treatment for 36-108 h. Ionic contents in the nutrient solution extracts are not equal to the value of adding ionic concentrations in the supplied nutrient solution to that in the water extract. Thus, a mathematical model was proposed for adjusting the composition of supplied nutrient solution to match plant requirements in the organic soilless culture system.

  6. Progress in high-efficient solution process organic photovoltaic devices fundamentals, materials, devices and fabrication

    CERN Document Server

    Li, Gang

    2015-01-01

    This book presents an important technique to process organic photovoltaic devices. The basics, materials aspects and manufacturing of photovoltaic devices with solution processing are explained. Solution processable organic solar cells - polymer or solution processable small molecules - have the potential to significantly reduce the costs for solar electricity and energy payback time due to the low material costs for the cells, low cost and fast fabrication processes (ambient, roll-to-roll), high material utilization etc. In addition, organic photovoltaics (OPV) also provides attractive properties like flexibility, colorful displays and transparency which could open new market opportunities. The material and device innovations lead to improved efficiency by 8% for organic photovoltaic solar cells, compared to 4% in 2005. Both academic and industry research have significant interest in the development of this technology. This book gives an overview of the booming technology, focusing on the solution process fo...

  7. Removal of low molecular organic acids from aqueous solutions with reactive extraction

    National Research Council Canada - National Science Library

    Dominika Szternel; Magdalena Regel-Rosocka; Maciej Wiśniewski

    2013-01-01

    ...) from aqueous solutions with reactive extraction. The results specifically show that the extraction efficiency of acids depends on the type of extractant, diluents of the organic phase and the initial pH of the aqueous phase...

  8. Impact of Fluorescent Lighting on Oxidation of Model Wine Solutions Containing Organic Acids and Iron.

    Science.gov (United States)

    Grant-Preece, Paris; Barril, Celia; Schmidtke, Leigh M; Clark, Andrew C

    2017-03-22

    Previous studies have provided evidence that light exposure can increase oxygen consumption in wine and that the photodegradation of iron(III) tartrate could contribute to this process. In the present study, model wine solutions containing iron(III) and various organic acids, either alone or combined, were stored in sealed clear glass wine bottles and exposed to light from fluorescent lamps. Dissolved oxygen was monitored, and afterward the organic acid degradation products were determined and the capacity of the solutions to bind sulfur dioxide, the main wine preservative, was assessed. In the dark controls, little or no dissolved oxygen was consumed and the organic acids were stable. In the irradiated solutions, dissolved oxygen was consumed at a rate that was dependent on the specific organic acid present, and the latter were oxidized to various carbonyl compounds. For the solutions containing tartaric acid, malic acid, and/or citric acid, irradiation increased their sulfur dioxide-binding capacity.

  9. Solvation of Lithium Irons in Mixed Organic Electrolyte Solutions by Electrospray Ionization Mass Spectroscopy

    OpenAIRE

    MATSUDA, Yoshiharu; FUKUSHIMA, Tsuyoshi; Hashimoto, Hiroyuki; ARAKAWA, Ryuichi

    2002-01-01

    Solvation of lithium ions in mixed organic electrolyte solutions for secondary lithium batteries was investigated by electrospray ionization mass spectroscopy. The electrolyte solutions were mixed binary solutions of diethyl carbonate (DEC), dimethyl carbonate (DMC), ethylene carbonate (EC),γ-butyrolactone (GBL), and propylene carbonate (PC) containing LiClO4. Lithium ions solvated mainly to two solvent molecules. The order of the inclination of the solvent molecules solvating to lithium ions...

  10. Solution processing of back electrodes for organic solar cells with inverted architecture

    NARCIS (Netherlands)

    Galagan, Y.; Shanmugam, S.; Teunissen, J.P.; Eggenhuisen, T.M.; Biezemans, A.F.K.V.; Van Gijseghem, T.; Groen, W.A.; Andriessen, R.

    2014-01-01

    Solution processing of the electrodes is a big challenge towards scaling up and R2R processing of organic solar cells. Inkjet printing is a non-contact printing method, it can be realized by solution processing at ambient condition and provides freedom of shape in the electrode pattern. The inkjet

  11. Polar solvents decrease the viscosity of high concentration IgG1 solutions through hydrophobic solvation and interaction: formulation and biocompatibility considerations.

    Science.gov (United States)

    Kamerzell, Tim J; Pace, Amanda L; Li, Megan; Danilenko, Dimitry M; McDowell, Michelle; Gokarn, Yatin R; Wang, Y John

    2013-04-01

    Low-volume protein dosage forms for subcutaneous injection pose unique challenges to the pharmaceutical scientist. Indeed, high protein concentrations are often required to achieve acceptable bioavailability and efficacy for many indications. Furthermore, high solution viscosities are often observed with formulations containing protein concentrations well above 150 mg/mL. In this work, we explored the use of polar solvents for reducing solution viscosity of high concentration protein formulations intended for subcutaneous injection. An immunoglobulin, IgG1, was used in this study. The thermodynamic preferential interaction parameter (Γ23 ) measured by differential scanning calorimetry, as well as Fourier transform infrared, Raman, and second-derivative UV spectroscopy, were used to characterize the effects of polar solvents on protein structure and to reveal important mechanistic insight regarding the nature of the protein-solvent interaction. Finally, the hemolytic potential and postdose toxicity in rats were determined to further investigate the feasibility of using these cosolvents for subcutaneous pharmaceutical formulations. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:1182-1193, 2013.

  12. Thermodynamic Analysis of the Conformational Transition in Aqueous Solutions of Isotactic and Atactic Poly(Methacrylic Acid and the Hydrophobic Effect

    Directory of Open Access Journals (Sweden)

    Ksenija Kogej

    2016-04-01

    Full Text Available The affinity of amphiphilic compounds for water is important in various processes, e.g., in conformational transitions of biopolymers, protein folding/unfolding, partitioning of drugs in the living systems, and many others. Herein, we study the conformational transition of two isomer forms of poly(methacrylic acid (PMA, isotactic (iPMA and atactic (aPMA, in water. These isomers are chemically equivalent and differ only in the arrangement of functional groups along the chain. A complete thermodynamic analysis of the transition of the PMA chains from the compact to the extended form (comprising the conformational transition in water in the presence of three alkali chlorides is conducted by determining the free energy, enthalpy, and entropy changes of the process as a function of temperature, and therefrom also the heat capacity change. The heat capacity change of the transition is positive (+20 J/K mol for aPMA and negative (−50 J/K mol for iPMA. This result suggests a different affinity of PMA isomers for water. The conformational transition of iPMA is parallel to the transfer of polar solutes into water, whereas that of aPMA agrees with the transfer of nonpolar solutes into water.

  13. GENETICALLY MODIFIED ORGANISMS – A SOLUTION TO WORLD HUNGER?

    Directory of Open Access Journals (Sweden)

    Željko Kaluđerović

    2013-02-01

    Full Text Available In 2011, GM crops were grown on 160 million hectares spread over 29 countries, on all continents, marking a 94-fold increase in the area since their first commercialization in 1996, and making it the fastest adopted crop technology in recent history. Main reasons for this expansion are, by the proponents of GM food, its safety, potential to revolutionize agriculture and benefit the farmers and consumers alike. On the other hand, there are indications that GMOs are harmful to the biodiversity and become eco-contaminants, and can, especially in the long terms, negatively affect the human health. Authors think that patenting of living organisms by the multinational companies is unacceptable and unfair from the bioethical perspective, not only because they tend to hold monopolies in production and trade of GM plants, but also because of their efforts to gain domination over the very life. Finally, analyses made by many scientists show that the thesis that "Gene Revolution" will resolve the problem of hunger in the world was not justified in the previous decade.

  14. ELUTION OF ORGANIC SOLUTES FROM DIFFERENT POLARITY SORBENTS USING SUBCRITICAL WATER. (R825394)

    Science.gov (United States)

    The intermolecular interactions between organic solutes and sorbent matrices under subcritical water conditions have been investigated at a pressure of 50 bar and temperatures ranging from 50 to 250°C. Both polar and nonpolar organics (chlorophenols, amines, n-alkanes...

  15. Identification of Organic Colorants in Art Objects by Solution Spectrophotometry: Pigments.

    Science.gov (United States)

    Billmeyer, Fred W., Jr.; And Others

    1981-01-01

    Describes solution spectrophotometry as a simple, rapid identification technique for organic paint pigments. Reports research which includes analytical schemes for the extraction and separation of organic pigments based on their solubilities, and the preparation of an extensive reference collection of spectral curves allowing their identification.…

  16. Influence of arbuscular mycorrhiza on organic solutes in maize leaves under salt stress.

    Science.gov (United States)

    Sheng, Min; Tang, Ming; Zhang, Fengfeng; Huang, Yanhui

    2011-07-01

    A pot experiment was conducted to examine the effect of the arbuscular mycorrhizal (AM) fungus, Glomus mosseae, on plant biomass and organic solute accumulation in maize leaves. Maize plants were grown in sand and soil mixture with three NaCl levels (0, 0.5, and 1.0 g kg(-1) dry substrate) for 55 days, after 15 days of establishment under non-saline conditions. At all salinity levels, mycorrhizal plants had higher biomass and higher accumulation of organic solutes in leaves, which were dominated by soluble sugars, reducing sugars, soluble protein, and organic acids in both mycorrhizal and non-mycorrhizal plants. The relative abundance of free amino acids and proline in total organic solutes was lower in mycorrhizal than in non-mycorrhizal plants, while that of reducing sugars was higher. In addition, the AM symbiosis raised the concentrations of soluble sugars, reducing sugars, soluble protein, total organic acids, oxalic acid, fumaric acid, acetic acid, malic acid, and citric acid and decreased the concentrations of total free amino acids, proline, formic acid, and succinic acid in maize leaves. In mycorrhizal plants, the dominant organic acid was oxalic acid, while in non-mycorrhizal plants, the dominant organic acid was succinic acid. All the results presented here indicate that the accumulation of organic solutes in leaves is a specific physiological response of maize plants to the AM symbiosis, which could mitigate the negative impact of soil salinity on plant productivity.

  17. Identification of Organic Colorants in Art Objects by Solution Spectrophotometry: Pigments.

    Science.gov (United States)

    Billmeyer, Fred W., Jr.; And Others

    1981-01-01

    Describes solution spectrophotometry as a simple, rapid identification technique for organic paint pigments. Reports research which includes analytical schemes for the extraction and separation of organic pigments based on their solubilities, and the preparation of an extensive reference collection of spectral curves allowing their identification.…

  18. Solution processed organic light-emitting diodes using the plasma cross-linking technology

    Science.gov (United States)

    He, Kongduo; Liu, Yang; Gong, Junyi; Zeng, Pan; Kong, Xun; Yang, Xilu; Yang, Cheng; Yu, Yan; Liang, Rongqing; Ou, Qiongrong

    2016-09-01

    Solution processed multilayer organic light-emitting diodes (OLEDs) present challenges, especially regarding dissolution of the first layer during deposition of a second layer. In this work, we first demonstrated a plasma cross-linking technology to produce a solution processed OLED. The surfaces of organic films can be cross-linked after mixed acetylene and Ar plasma treatment for several tens of seconds and resist corrosion of organic solvent. The film thickness and surface morphology of emissive layers (EMLs) with plasma treatment and subsequently spin-rinsed with chlorobenzene are nearly unchanged. The solution processed triple-layer OLED is successfully fabricated and the current efficiency increases 50% than that of the double-layer OLED. Fluorescent characteristics of EMLs are also observed to investigate factors influencing the efficiency of the triple-layer OLED. Plasma cross-linking technology may open up a new pathway towards fabrication of all-solution processed multilayer OLEDs and other soft electronic devices.

  19. Patterning technology for solution-processed organic crystal field-effect transistors

    OpenAIRE

    Yun Li; Huabin Sun; Yi Shi; Kazuhito Tsukagoshi

    2014-01-01

    Organic field-effect transistors (OFETs) are fundamental building blocks for various state-of-the-art electronic devices. Solution-processed organic crystals are appreciable materials for these applications because they facilitate large-scale, low-cost fabrication of devices with high performance. Patterning organic crystal transistors into well-defined geometric features is necessary to develop these crystals into practical semiconductors. This review provides an update on recent development...

  20. Influence of Organic Inhibitor on Corrosion Resistance of Steel in Simulated Concrete Pore Solution

    OpenAIRE

    Cai, Jingshun S.; C. C. CHEN; Liu, J. Z.; Liu, J. P.

    2014-01-01

    Organic corrosion inhibitor is one of lower cost technologies that limit the deterioration of concrete structures. The influence of a newly prepared organic corrosion inhibitor on the corrosion behavior of carbon steel in simulated concrete pore solution was investigated by polarization curves, electrochemical impedance spectroscopy, and so on. The effect of organic corrosion inhibitors on concrete working performance was also studied. The results show that the corrosion rate decreases with t...

  1. The response of hydrophobic organics and potential toxicity in streams to urbanization of watersheds in six metropolitan areas of the United States

    Science.gov (United States)

    Bryant, W.L.; Goodbred, S.L.

    2009-01-01

    Semipermeable membrane devices (SPMDs) were deployed in streams along a gradient of urban land-use intensity in and around six metropolitan areas: Atlanta, Georgia; Raleigh - Durham, North Carolina; and Denver - Fort Collins, Colorado, in 2003; and Dallas - Fort Worth, Texas; Milwaukee - Green Bay, Wisconsin; and Portland, Oregon, in 2004 to examine relations between percent urban land cover in watersheds and the occurrence, concentrations, and potential toxicity of hydrophobic compounds. Of the 142 endpoints measured in SPMD dialysates, 30 were significantly (alpha = 0.05) related to the percent of urban land cover in the watersheds in at least one metropolitan area. These 30 endpoints included the aggregated measures of the total number of compounds detected and relative toxicity (Microtox?? and P450RGS assays), in addition to the concentrations of 27 individual hydrophobic compounds. The number of compounds detected, P450RGS assay values, and the concentrations of pyrogenic polycyclic aromatic hydrocarbons (PAHs) were significantly related to percent urban land cover in all six metropolitan areas. Pentachloroanisole, the most frequently detected compound, was significantly related to urban land cover in all metropolitan areas except Dallas - Fort Worth. Petrogenic PAHs and dibenzofurans were positively related to percent urban land cover in Atlanta, Raleigh - Durham, Denver, and Milwaukee - Green Bay. Results for other endpoints were much more variable. The number of endpoints significantly related to urban land cover ranged from 6 in Portland to 21 Raleigh-Durham. Based on differences in the number and suite of endpoints related to urban intensity, these results provide evidence of differences in factors governing source strength, transport, and/or fate of hydrophobic compounds in the six metropolitan areas studied. The most consistent and significant results were that bioavailable, aryl hydrocarbon receptor agonists increase in streams as basins become

  2. Solution-Processed Organic Thin-Film Transistor Array for Active-Matrix Organic Light-Emitting Diode

    Science.gov (United States)

    Harada, Chihiro; Hata, Takuya; Chuman, Takashi; Ishizuka, Shinichi; Yoshizawa, Atsushi

    2013-05-01

    We developed a 3-in. organic thin-film transistor (OTFT) array with an ink-jetted organic semiconductor. All layers except electrodes were fabricated by solution processes. The OTFT performed well without hysteresis, and the field-effect mobility in the saturation region was 0.45 cm2 V-1 s-1, the threshold voltage was 3.3 V, and the on/off current ratio was more than 106. We demonstrated a 3-in. active-matrix organic light-emitting diode (AMOLED) display driven by the OTFT array. The display could provide clear moving images. The peak luminance of the display was 170 cd/m2.

  3. Interconnection of salt-induced hydrophobic compaction and secondary structure formation depends on solution conditions: revisiting early events of protein folding at single molecule resolution.

    Science.gov (United States)

    Haldar, Shubhasis; Chattopadhyay, Krishnananda

    2012-03-30

    What happens in the early stage of protein folding remains an interesting unsolved problem. Rapid kinetics measurements with cytochrome c using submillisecond continuous flow mixing devices suggest simultaneous formation of a compact collapsed state and secondary structure. These data seem to indicate that collapse formation is guided by specific short and long range interactions (heteropolymer collapse). A contrasting interpretation also has been proposed, which suggests that the collapse formation is rapid, nonspecific, and a trivial solvent related compaction, which could as well be observed by a homopolymer (homopolymer collapse). We address this controversy using fluorescence correlation spectroscopy (FCS), which enables us to monitor the salt-induced compaction accompanying collapse formation and the associated time constant directly at single molecule resolution. In addition, we follow the formation of secondary structure using far UV CD. The data presented here suggest that both these models (homopolymer and heteropolymer) could be applicable depending on the solution conditions. For example, the formation of secondary structure and compact state is not simultaneous in aqueous buffer. In aqueous buffer, formation of the compact state occurs through a two-state co-operative transition following heteropolymer formalism, whereas secondary structure formation takes place gradually. In contrast, in the presence of urea, a compaction of the protein radius occurs gradually over an extended range of salt concentration following homopolymer formalism. The salt-induced compaction and the formation of secondary structure take place simultaneously in the presence of urea.

  4. Isotherm-Based Thermodynamic Models for Solute Activities of Organic Acids with Consideration of Partial Dissociation.

    Science.gov (United States)

    Nandy, Lucy; Ohm, Peter B; Dutcher, Cari S

    2016-06-23

    Organic acids make up a significant fraction of the organic mass in atmospheric aerosol particles. The calculation of gas-liquid-solid equilibrium partitioning of the organic acid is therefore critical for accurate determination of atmospheric aerosol physicochemical properties and processes such as new particle formation and activation to cloud condensation nuclei. Previously, an adsorption isotherm-based statistical thermodynamic model was developed for capturing solute concentration-activity relationships for multicomponent aqueous solutions over the entire concentration range (Dutcher et al. J. Phys. Chem. C/A 2011, 2012, 2013), with model parameters for energies of adsorption successfully related to dipole-dipole electrostatic forces in solute-solvent and solvent-solvent interactions for both electrolytes and organics (Ohm et al. J. Phys. Chem. A 2015). However, careful attention is needed for weakly dissociating semivolatile organic acids. Dicarboxylic acids, such as malonic acid and glutaric acid are treated here as a mixture of nondissociated organic solute (HA) and dissociated solute (H(+) + A(-)). It was found that the apparent dissociation was greater than that predicted by known dissociation constants alone, emphasizing the effect of dissociation on osmotic and activity coefficient predictions. To avoid additional parametrization from the mixture approach, an expression was used to relate the Debye-Hückel hard-core collision diameter to the adjustable solute-solvent intermolecular distance. An improved reference state treatment for electrolyte-organic aqueous mixtures, such as that observed here with partial dissociation, has also been proposed. This work results in predictive correlations for estimation of organic acid and water activities for which there is little or no activity data.

  5. Gel formation driven by tunable hydrophobic domain: design of acrylamide macromonomer with oligo hydrophobic segment.

    Science.gov (United States)

    Nitta, Kyohei; Miyake, Junpei; Watanabe, Junji; Ikeda, Yoshiyuki

    2012-04-09

    Nowadays, biomaterials with amphiphilic properties are undergoing remarkable development. Here, we present one such development, in which we prepared amphiphilic graft copolymers, with a main chain composed of hydroxyethyl acrylamide (HEAA), to introduce hydrophilicity, and a side chain composed of poly(trimethylene carbonate) (PTMC) to introduce tunable hydrophobicity. These macromonomers were created with a novel molecular design, which introduced a ring-opening polymerization by the hydroxyl end group of HEAA in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene, and were analyzed by (1)H NMR and gel permeation chromatography. The amphiphilic graft copolymers were shown to form a hydrogel, the swelling ratio of which was greatly influenced by the number of trimethylene carbonate units. These copolymers also exhibited the Tyndall phenomenon in aqueous solution; they aggregated spontaneously due to hydrogen bonding and hydrophobic interactions, and a sodium 8-anilino-1-naphthalenesulfonate (ANS) fluorescence probe was introduced into the hydrophobic domain. The solution property of ANS in the polymer solution was analyzed by fluorescence measurement and (1)H NMR. The maximum fluorescence wavelength of ANS shifted to shorter wavelengths as the degree of polymerization of the hydrophobic PTMC, the composition of the macromonomer, and the concentration of the copolymer increased. The resulting copolymer formed a polymer micelle structure due to the tunable hydrophobic domain formation in selected solvents. Therefore, these amphiphilic graft copolymers containing a PTMC segment are excellent candidates for use as hydrophobic drug delivery carriers.

  6. Surface analysis of selected hydrophobic materials

    Science.gov (United States)

    Wisniewska, Sylwia Katarzyna

    This dissertation contains a series of studies on hydrophobic surfaces by various surface sensitive techniques such as contact angle measurements, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Hydrophobic surfaces have been classified as mineral surfaces, organic synthetic surfaces, or natural biological surfaces. As a model hydrophobic mineral surface, elemental sulfur has been selected. The sulfur surface has been characterized for selected allotropic forms of sulfur such as rhombic, monoclinic, plastic, and cyclohexasulfur. Additionally, dextrin adsorption at the sulfur surface was measured. The structure of a dextrin molecule showing hydrophobic sites has been presented to support the proposed hydrophobic bonding nature of dextrin adsorption at the sulfur surface. As a model organic hydrophobic surface, primary fatty amines such as dodecylamine, hexadecylamine, and octadecylamine were chosen. An increase of hydrophobicity, significant changes of infrared bands, and surface topographical changes with time were observed for each amine. Based on the results it was concluded that hydrocarbon chain rearrangement associated with recrystallization took place at the surface during contact with air. A barley straw surface was selected as a model of biological hydrophobic surfaces. The differences in the contact angles for various straw surfaces were explained by the presence of a wax layer. SEM images confirmed the heterogeneity and complexity of the wax crystal structure. AFM measurements provided additional structural details including a measure of surface roughness. Additionally, straw degradation as a result of conditioning in an aqueous environment was studied. Significant contact angle changes were observed as soon as one day after conditioning. FTIR studies showed a gradual wax layer removal due to straw surface decomposition. SEM and AFM images revealed topographical changes and biological

  7. Adsorption of organic acids from dilute aqueous solution onto activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S.W.

    1980-06-01

    The radioisotope technique was used to study the removal of organic acid contaminants from dilute aqueous solutions onto activated carbon. Acetic acid, propionic acid, n-butyric acid, n-hexanoic acid and n-heptanoic acid were studied at 278, 298, and 313/sup 0/K. Three bi-solute acid mixtures (acetic and propionic acids, acetic and butanoic acids, and propionic and butanoic acids) were studied at 278 and 298/sup 0/K. Isotherms of the single-solute systems were obtained at three different temperatures in the very dilute concentration region (less than 1% by weight). These data are very important in the prediction of bi-solute equilibrium data. A Polanyi-based competitive adsorption potential theory was used to predict the bi-solute equilibrium uptakes. Average errors between calculated and experimental data ranges from 4% to 14%. It was found that the competitive adsorption potential theory gives slightly better results than the ideal adsorbed solution theory.

  8. Characterization of surface hydrophobicity of engineered nanoparticles.

    Science.gov (United States)

    Xiao, Yao; Wiesner, Mark R

    2012-05-15

    The surface chemistry of nanoparticles, including their hydrophobicity, is a key determinant of their fate, transport and toxicity. Engineered NPs often have surface coatings that control the surface chemistry of NPs and may dominate the effects of the nanoparticle core. Suitable characterization methods for surface hydrophobicity at the nano-scale are needed. Three types of methods, surface adsorption, affinity coefficient and contact angle, were investigated in this study with seven carbon and metal based NPs with and without coatings. The adsorption of hydrophobic molecules, Rose Bengal dye and naphthalene, on NPs was used as one measure of hydrophobicity and was compared with the relative affinity of NPs for octanol or water phases, analogous to the determination of octanol-water partition coefficients for organic molecules. The sessile drop method was adapted for measuring contact angle of a thin film of NPs. Results for these three methods were qualitatively in agreement. Aqueous-nC(60) and tetrahydrofuran-nC(60) were observed to be more hydrophobic than nano-Ag coated with polyvinylpyrrolidone or gum arabic, followed by nano-Ag or nano-Au with citrate-functionalized surfaces. Fullerol was shown to be the least hydrophobic of seven NPs tested. The advantages and limitations of each method were also discussed.

  9. Hydrophobically modified polyelectrolytes: Characterization, aggregation and adsorption

    Science.gov (United States)

    Islam, Mohammad Ferdous

    The focus of our work was to experimentally study the aggregation and adsorption behavior of model HM polyelectrolytes. Hydrophobically modified alkali soluble emulsions (HASE), the model HM polyelectrolytes, were chosen because they had complex architecture yet possessed key variables for systematic study. The HASE polymers have methacrylic acid (MAA) and ethyl acrylate (EA) in the backbone with pendent hydrophobic groups. Characterization of a single molecule is an important first step in understanding the aggregation and adsorption of these polymers. However, characterizations of the HASE polymers using conventional techniques such as gel permeation chromatography or static light scattering were difficult because of the hydrophobic association. In this study, two different approaches have been taken to prevent the hydrophobic association in aqueous solution: (1) hydrolyze the polymer to cleave the hydrophobic constituents, and (2) use methyl beta-cyclodextrin that has a hydrophobic cavity and a hydrophilic outer shell, to shield the hydrophobes from associating. By taking these two approaches and using gel permeation chromatography (GPC), dynamic (DLS) and static (SLS) light scattering techniques, the molecular weight, hydrodynamic radius and radius of gyration of a single molecule were determined. Except for one chemical site, we were able to determine that branching or grafting did not occur in the polymer chain during synthesis. Our aggregation studies showed that, in aqueous solutions, the HASE polymers formed small aggregates (presumably single micelles of single or a few chains) and large aggregates (presumably formed by bridging between micelles). The radii and masses of the larger aggregates, measured using DLS and SLS, were found to increase with an increase in the polymer concentration, indicating an open association process for the HASE polymers. Our SLS results also showed that, at high salt concentration, the aggregates of the HASE polymer with

  10. Solid- and solution-phase organics dictate copper distribution and speciation in multicomponent systems containing ferrihydrite, organic matter, and montmorillonite.

    Science.gov (United States)

    Martínez-Villegas, Nadia; Martínez, Carmen Enid

    2008-04-15

    Copper retention by ferrihydrite, leaf compost, and montmorillonite was studied over 8 months in systems that emulate a natural soil where different solid phases compete for Cu through a common solution in a compartmentalized batch reactor. Copper speciation in solution (total dissolved, DPASV-labile, and free) and exchangeable and total Cu in individual solid phases were determined. Organic carbon in solution (DOC) and that retained by the mineral phases were also determined. Cu sorption reached steady-state after 4 months and accounted for 80% of the Cu initially added to the system (0.15 mg L(-1)). The remaining 20% stayed in solution as nonlabile (82.8%), labile (17%), and free (0.2%) Cu species. Copper sorption followed the order organic matter > silicate clays > iron oxides. Within each solid phase, exchangeable Cu was < or = 10% of the total Cu sorbed. DOC reached steady state (22 mg L(-1)) after 4 months and seemed to control Cu solubility and sorption behavior by the formation of soluble Cu-DOC complexes and by sorbing onto the mineral phases. DOC sorption onto ferrihydrite prevented Cu retention by this solid phase. Using a multicomponent system and 8 months equilibrations, we were able to capture some of the more important aspects of the complexity of soil environments bytaking into account diffusion processes and competition among solid- and solution-phase soil constituents in the retention of a metal cation.

  11. Hydrophobically modified polyelectrolytes : synthesis, properties and interactions with surfactants

    NARCIS (Netherlands)

    Nieuwkerk, A.C.

    1998-01-01

    Hydrophobically modified polyelectrolytes can form micelle-like aggregates, so-called microdomains, in aqueous solution. The hydrophobic side chains constitute the apolar inner part of these microdomains and the hydrophilic groups on the polyelectrolyte backbone are at the surface of the

  12. Morphology Development in Solution-Processed Functional Organic Blend Films: An In Situ Viewpoint

    KAUST Repository

    Richter, Lee J.

    2017-04-17

    Solution-processed organic films are a facile route to high-speed, low cost, large-area deposition of electrically functional components (transistors, solar cells, emitters, etc.) that can enable a diversity of emerging technologies, from Industry 4.0, to the Internet of things, to point-of-use heath care and elder care. The extreme sensitivity of the functional performance of organic films to structure and the general nonequilibrium nature of solution drying result in extreme processing-performance correlations. In this Review, we highlight insights into the fundamentals of solution-based film deposition afforded by recent state-of-the-art in situ measurements of functional film drying. Emphasis is placed on multimodal studies that combine surface-sensitive X-ray scattering (GIWAXS or GISAXS) with optical characterization to clearly define the evolution of solute structure (aggregation, crystallinity, and morphology) with film thickness.

  13. Enhanced photovoltaic performance of organic/silicon nanowire hybrid solar cells by solution-evacuated method.

    Science.gov (United States)

    Wang, Wei-Li; Zou, Xian-Shao; Zhang, Bin; Dong, Jun; Niu, Qiao-Li; Yin, Yi-An; Zhang, Yong

    2014-06-01

    A method has been developed to fabricate organic-inorganic hybrid heterojunction solar cells based on n-type silicon nanowire (SiNW) and poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) hybrid structures by evacuating the PEDOT:PSS solution with dip-dropping on the top of SiNWs before spin-coating (solution-evacuating). The coverage and contact interface between PEDOT:PSS and SiNW arrays can be dramatically enhanced by optimizing the solution-evacuated time. The maximum power conversion efficiency (PCE) reaches 9.22% for a solution-evacuated time of 2 min compared with 5.17% for the untreated pristine device. The improvement photovoltaic performance is mainly attributed to better organic coverage and contact with an n-type SiNW surface.

  14. Institutionalization of Organized Industrial Estates in Turkey, Problems Encountered and Proposed Solutions

    Directory of Open Access Journals (Sweden)

    Hasan DAĞLAR

    2015-12-01

    Full Text Available In the aim of the study is to determine the institutionalization degree of organized industrial estates and to identify the faced problems and to develop solutions for these problems. By using survey method, information about problems and institutionalization status of organized industrial estates were obtained from managers of the active organized industrial estates. The problems of organized industrial estates are related to the management structure, qualified staff, energy, transportation, regulation and public improvements. Formalization, professionalism, accountability, transparency and social responsibility have been identified as the factors about the institutionalization of organized industrial estates in Turkey according to factor analysis. It could be argued that organized industrial estates in Turkey have an institutional structure and they have institutionalized. However, it could be said that organized industrial estates which operate in 80 cities of Turkey and more than one are in some cities are not at the same level of institutionalization.

  15. ICT solutions in intelligent organizations as challenges in a knowledge economy

    Directory of Open Access Journals (Sweden)

    Adamczewski Piotr

    2016-12-01

    Full Text Available Solutions of the Information and Communication Technology (ICT are the foundation of modern economic organizations in a knowledge economy. This is the case in particular in intelligent organizations, for which the advanced ICT infrastructure is the sine qua non condition for the effective knowledge management. This article is aimed at describing the role of modern ICT trends, which are described as SMAC, (Social, Mobility, Analytics, Cloud, and are becoming an essential ICT element supporting management processes. Such solutions enable to create new models of organization operations on the global markets using strategic resources, such as the knowledge supported with SMAC solutions. The arguments are illustrated with results of own research conducted by the author in 2014-2016 in selected SME’s from the Mazowieckie and Wielkopolskie rovinces and their reference to the general development trends in this area.

  16. All solution processable organic photovoltaic cells using DMDCNQI as an organic N-type buffer layer.

    Science.gov (United States)

    Yang, Eui Yeol; So, Byoung Min; Chung, Chan Moon; Oh, Se Young

    2012-01-01

    Organic photovoltaic cells consisting of ITO/PEDOT-PSS/P3HT:PCBM/TiO(x)/DMDCNQI/Al have been fabricated by using dip-coated DMDCNQI layer as a cathode buffer material. We have investigated the physical effects of charge transfer complex and wettability of DMDCNQI between TiO(x)/P3HT:PCBM layer and Al cathode electrode on the performance of organic photovoltaic cell. The photovoltaic cell fabricated with a dip-coated DMDCNQI layer exhibited almost similar performance compared to the device using conventional evaporated DMDCNQI layer. Especially, the power conversion efficiency of the prepared organic photovoltaic cell using TiO(x)/DMDCNQI layer was improved to 3.1%, which is mainly due to the decrease in the low contact resistance of organic-metal interface.

  17. Modeling phase distribution of water-soluble organics in aqueous solutions using surface tension data

    Science.gov (United States)

    Cline, B.; Hiatt, J.; Aumann, E.; Cabrera, J.; Tabazadeh, A.

    2006-12-01

    A good fraction (greater than 30 percent) of submicron particle mass in the atmosphere is often composed of water-soluble organic carbon. Identifiable, water-miscible organics, such as, known sugars, small alcohols, small diacids, etc. comprise only a small fraction of the water-soluble mass (about 1-2 percent). Most of the water-soluble mass is often composed of unidentifiable, humic-like materials, which are commonly refereed to as HULIS. Humic substances are known to form colloids in aqueous solutions at very low aqueous concentrations. Thus, it is likely for HULIS to also be colloid-forming in aqueous solutions. Here, we present surface tension measurements of water-miscible and colloid-forming organics, using methanol and sodium laurate as analogs, respectively. By relating the change in surface tension to chemical potential of the solution, we determine a relationship between surface tension and the surface excess of solute; that is, the number of molecules of solute adsorbed at the surface. Assuming surface acts as a monolayer, we model the adsorption with a Langmuir isotherm to extract the surface excess as a function of solute mole fraction. This relationship allows us to calculate the solute's distribution between bulk and surface phases for methanol, and in bulk, surface and colloid phases for sodium laurate. A colloid of sodium laurate contains approximately 100 laurate anions in a spherical cluster. We present adsorption constants for methanol and sodium laurate (derived from our surface tension data), critical micelle concentration for sodium laurate (derived from our surface tension data), and all the other thermocehmical constants (obtained from the literature) required to constrain a model for determining phase partitioning of organics in aqueous solutions.

  18. Self-organization and solution of shortest-path optimization problems with memristive networks

    Science.gov (United States)

    Pershin, Yuriy V.; Di Ventra, Massimiliano

    2013-07-01

    We show that memristive networks, namely networks of resistors with memory, can efficiently solve shortest-path optimization problems. Indeed, the presence of memory (time nonlocality) promotes self organization of the network into the shortest possible path(s). We introduce a network entropy function to characterize the self-organized evolution, show the solution of the shortest-path problem and demonstrate the healing property of the solution path. Finally, we provide an algorithm to solve the traveling salesman problem. Similar considerations apply to networks of memcapacitors and meminductors, and networks with memory in various dimensions.

  19. Hydrophobic treatment of concrete

    NARCIS (Netherlands)

    Vries, J. de; Polder, R.B.

    1996-01-01

    As part of the maintenance policy of the Dutch Ministry of Transport, Civil Engineering Division, hydrophobic treatment of concrete was considered as an additional protective measure against penetration of aggressive substances, for instance deicing salts in bridge decks. A set of tests was designed

  20. Hydrophobic treatment of concrete

    NARCIS (Netherlands)

    Vries, J.de; Polder, R.B.

    1997-01-01

    As part of the maintenance policy of the dutch Ministry of Transport, Civil Engineering Division, hydrophobic treatment of concrete was considered as an additional protective measure against penetration of aggressive substances, for instance deicing salts in bridge decks. A set of tests was designed

  1. Patterning technology for solution-processed organic crystal field-effect transistors

    Science.gov (United States)

    Li, Yun; Sun, Huabin; Shi, Yi; Tsukagoshi, Kazuhito

    2014-04-01

    Organic field-effect transistors (OFETs) are fundamental building blocks for various state-of-the-art electronic devices. Solution-processed organic crystals are appreciable materials for these applications because they facilitate large-scale, low-cost fabrication of devices with high performance. Patterning organic crystal transistors into well-defined geometric features is necessary to develop these crystals into practical semiconductors. This review provides an update on recent development in patterning technology for solution-processed organic crystals and their applications in field-effect transistors. Typical demonstrations are discussed and examined. In particular, our latest research progress on the spin-coating technique from mixture solutions is presented as a promising method to efficiently produce large organic semiconducting crystals on various substrates for high-performance OFETs. This solution-based process also has other excellent advantages, such as phase separation for self-assembled interfaces via one-step spin-coating, self-flattening of rough interfaces, and in situ purification that eliminates the impurity influences. Furthermore, recommendations for future perspectives are presented, and key issues for further development are discussed.

  2. Patterning technology for solution-processed organic crystal field-effect transistors

    Directory of Open Access Journals (Sweden)

    Yun Li

    2014-04-01

    Full Text Available Organic field-effect transistors (OFETs are fundamental building blocks for various state-of-the-art electronic devices. Solution-processed organic crystals are appreciable materials for these applications because they facilitate large-scale, low-cost fabrication of devices with high performance. Patterning organic crystal transistors into well-defined geometric features is necessary to develop these crystals into practical semiconductors. This review provides an update on recent development in patterning technology for solution-processed organic crystals and their applications in field-effect transistors. Typical demonstrations are discussed and examined. In particular, our latest research progress on the spin-coating technique from mixture solutions is presented as a promising method to efficiently produce large organic semiconducting crystals on various substrates for high-performance OFETs. This solution-based process also has other excellent advantages, such as phase separation for self-assembled interfaces via one-step spin-coating, self-flattening of rough interfaces, and in situ purification that eliminates the impurity influences. Furthermore, recommendations for future perspectives are presented, and key issues for further development are discussed.

  3. Effect of Organic Materials on Speciation of Cooper in Soil Solution

    Institute of Scientific and Technical Information of China (English)

    WANGGUO; CHENJIANBIN; 等

    1999-01-01

    Incubation of two soils,a red soil derived from granodiorte and a fluvo-aquic soil from alluvial deposit,with rice straw,Chinese milk vetch and pig manure under submerged condition were conducted to study the species of Cu in soil solutions as affected by the organic materials.The organic materials increased total soluble Cu by raising dissolved organic carbon(DOC) in soil solution when the solution pH values were below the range in which Cu deposited quickly.When the solution pH rose to this rage,the increase of DOC did not raise total soluble Cu.Total soluble Cu in all the treatments dropped with incubation time.After adding organic materials labile Cu dropped with incubation time and decreased sharply in the pH range of Cu precipitation.Addition of organic materials enhanced slowly labile Cu but depressed the ratio of labile Cu to total soluble Cu.Slowly labile Cu decreased with incubation time.Sepwise multiple linear regression analysis showed that total soluble Cu was positively correlated with Eh and DOC(P=0.0025),labile Cu was negatively correlated with pH(P=0.0118),and slowly labile Cu was positively correlated with Eh and DOC(P=0.0022).Both the labile and slowly labile Cu were correlated with total soluble Cu at extremely significant levels.

  4. Solution-printed organic semiconductor blends exhibiting transport properties on par with single crystals.

    Science.gov (United States)

    Niazi, Muhammad R; Li, Ruipeng; Qiang Li, Er; Kirmani, Ahmad R; Abdelsamie, Maged; Wang, Qingxiao; Pan, Wenyang; Payne, Marcia M; Anthony, John E; Smilgies, Detlef-M; Thoroddsen, Sigurdur T; Giannelis, Emmanuel P; Amassian, Aram

    2015-11-23

    Solution-printed organic semiconductors have emerged in recent years as promising contenders for roll-to-roll manufacturing of electronic and optoelectronic circuits. The stringent performance requirements for organic thin-film transistors (OTFTs) in terms of carrier mobility, switching speed, turn-on voltage and uniformity over large areas require performance currently achieved by organic single-crystal devices, but these suffer from scale-up challenges. Here we present a new method based on blade coating of a blend of conjugated small molecules and amorphous insulating polymers to produce OTFTs with consistently excellent performance characteristics (carrier mobility as high as 6.7 cm(2) V(-1) s(-1), low threshold voltages ofcrystallization can yield solution-printed polycrystalline organic semiconductor films with transport properties and other figures of merit on par with their single-crystal counterparts.

  5. Endothelial cell preservation at hypothermic to normothermic conditions using clinical and experimental organ preservation solutions.

    Science.gov (United States)

    Post, Ivo C J H; de Boon, Wadim M I; Heger, Michal; van Wijk, Albert C W A; Kroon, Jeffrey; van Buul, Jaap D; van Gulik, Thomas M

    2013-10-15

    Endothelial barrier function is pivotal for the outcome of organ transplantation. Since hypothermic preservation (gold standard) is associated with cold-induced endothelial damage, endothelial barrier function may benefit from organ preservation at warmer temperatures. We therefore assessed endothelial barrier integrity and viability as function of preservation temperature and perfusion solution, and hypothesized that endothelial cell preservation at subnormothermic conditions using metabolism-supporting solutions constitute optimal preservation conditions. Human umbilical vein endothelial cells (HUVEC) were preserved at 4-37°C for up to 20 h using Ringer's lactate, histidine-tryptophan-ketoglutarate solution, University of Wisconsin (UW) solution, Polysol, or endothelial cell growth medium (ECGM). Following preservation, the monolayer integrity, metabolic capacity, and ATP content were determined as positive parameters of endothelial cell viability. As negative parameters, apoptosis, necrosis, and cell activation were assayed. A viability index was devised on the basis of these parameters. HUVEC viability and barrier integrity was compromised at 4°C regardless of the preservation solution. At temperatures above 20°C, the cells' metabolic demands outweighed the preservation solutions' supporting capacity. Only UW maintained HUVEC viability up to 20°C. Despite high intracellular ATP content, none of the solutions were capable of sufficiently preserving HUVEC above 20°C except for ECGM. Optimal HUVEC preservation is achieved with UW up to 20°C. Only ECGM maintains HUVEC viability at temperatures above 20°C. © 2013 Elsevier Inc. All rights reserved.

  6. Contacts Between Alcohols in Water Are Random Rather than Hydrophobic.

    Science.gov (United States)

    Rankin, Blake M; Ben-Amotz, Dor; van der Post, Sietse T; Bakker, Huib J

    2015-02-19

    Given the importance of water-mediated hydrophobic interactions in a wide range of biological and synthetic self-assembly processes, it is remarkable that both the sign and the magnitude of the hydrophobic interactions between simple amphiphiles, such as alcohols, remain unresolved. To address this question, we have performed Raman hydration-shell vibrational spectroscopy and polarization-resolved femtosecond infrared experiments, as well as random mixing and molecular dynamics simulations. Our results indicate that there are no more hydrophobic contacts in aqueous solutions of alcohols ranging from methanol to tertiary butyl alcohol than in random mixtures of the same concentration. This implies that the interaction between small hydrophobic groups is weaker than thermal energy fluctuations. Thus, the corresponding water-mediated hydrophobic interaction must be repulsive, with a magnitude sufficient to negate the attractive direct van der Waals interaction between the hydrophobic groups.

  7. All solution processing of ITO-free organic solar cell modules directly on barrier foil

    DEFF Research Database (Denmark)

    Angmo, Dechan; Hösel, Markus; Krebs, Frederik C

    2012-01-01

    In this study, we demonstrate fully solution processed semi-transparent silver electrodes on flexible substrates having a sheet resistance as low as 5Ω/□ and transmittance of ∼30% at 550nm. We demonstrate the use of this electrode as a substitute for ITO in an inverted organic solar cell (OSC...... and processing cost and is a cost-effective alternative to ITO for low-cost organic solar cells....

  8. A-D-A small molecules for solution-processed organic photovoltaic cells.

    Science.gov (United States)

    Ni, Wang; Wan, Xiangjian; Li, Miaomiao; Wang, Yunchuang; Chen, Yongsheng

    2015-03-25

    A-D-A small molecules have drawn more and more attention in solution-processed organic solar cells due to the advantages of a diversity of structures, easy control of energy levels, etc. Recently, a power conversion efficiency of nearly 10% has been achieved through careful material design and device optimization. This feature article reviews recent representative progress in the design and application of A-D-A small molecules in organic photovoltaic cells.

  9. Highly Efficient, Simplified, Solution-Processed Thermally Activated Delayed-Fluorescence Organic Light-Emitting Diodes.

    Science.gov (United States)

    Kim, Young-Hoon; Wolf, Christoph; Cho, Himchan; Jeong, Su-Hun; Lee, Tae-Woo

    2016-01-27

    Highly efficient, simplified, solution-processed thermally activated delayed-fluorescence organic light-emitting diodes can be realized by using pure-organic thermally activated delayed fluorescence emitters and a multifunctional buffer hole-injection layer, in which high EQE (≈24%) and current efficiency (≈73 cd A(-1) ) are demonstrated. High-efficiency fluorescence red-emitting and blue-emitting devices can also be fabricated in this manner.

  10. A hybrid CMOS-imager with integrated solution-processable organic photodiodes

    OpenAIRE

    Baierl, Daniela

    2013-01-01

    The solution-processability of organic photodetectors allows a straightforward combination with other materials and technologies, including inorganic ones, without increasing cost and process complexity significantly compared to conventional crystalline semiconductors. Present CMOS-imagers exhibit a small pixel fill factor of about 30 % which decreases the light sensitivity significantly. The fill factor can be increased up to 100 % by replacing the silicon photodiodes with an organic ph...

  11. Preparation and Characterization of Organic-Inorganic Hybrid Hydrogel Electrolyte Using Alkaline Solution

    Directory of Open Access Journals (Sweden)

    Masanobu Chiku

    2011-09-01

    Full Text Available Organic-inorganic hybrid hydrogel electrolytes were prepared by mixing hydrotalcite, cross-linked potassium poly(acrylate and 6 M KOH solution. The organic-inorganic hybrid hydrogel electrolytes had high ionic conductivity (0.456–0.540 S cm−1 at 30 °C. Moreover, the mechanical strength of the hydrogel electrolytes was high enough to form a 2–3 mm thick freestanding membrane because of the reinforcement with hydrotalcite.

  12. PREPARATION OF NANOMETER TiO2 ORGANIC SOLUTION-EFFECT OF ORGANIC SILOXANE ON SOL PROPERTIES

    Institute of Scientific and Technical Information of China (English)

    Bi-yao Wu; Dao-hong Zhang

    2004-01-01

    A homogeneous longtime stabilized transparent nanometer TiO2 organic solution was obtained by means of the simultaneous hydrolysis and co-polycodensation of tetrabutyltitanate (TBT) and methacryloxypropyltrimethoxysilane (MAPTMS) by the sol-gel process. The particle size of nanometer titanium dioxide was controlled by use of bifunctional silanes, such as diphenyldimethoxysilane (DPDMS), diphenyldiethoxysilane (DPDES) and dimethyldiethoxysilane (DMDES). The effect of TiO2 content in the solution on the refractive index of system was discussed in detail. The result shows that the refractive index of solution increases linearly with TiO2 content. The refractive index of the three hybrid nanorneter materials attained 1.6053, 1.5846 and 1.5346, respectively. The size of nanometer particles was characterized by TEM and the particle diameter thus obtained is in the range of 20-90 nm. FT-IR spectra of the materials show that the TiO-Si bond is formed.

  13. Solution-Processed Metal Oxides as Efficient Carrier Transport Layers for Organic Photovoltaics.

    Science.gov (United States)

    Choy, Wallace C H; Zhang, Di

    2016-01-27

    Carrier (electron and hole) transport layers (CTLs) are essential components for boosting the performance of various organic optoelectronic devices such as organic solar cells and organic light-emitting diodes. Considering the drawbacks of conventional CTLs (easily oxidized/unstable, demanding/costly fabrication, etc.), transition metal oxides with good carrier transport/extraction and superior stability have drawn extensive research interest as CTLs for next-generation devices. In recent years, many research efforts have been made toward the development of solution-based metal oxide CTLs with the focus on low- or even room-temperature processes, which can potentially be compatible with the deposition processes of organic materials and can significantly contribute to the low-cost and scale-up of organic devices. Here, the recent progress of different types of solution-processed metal oxide CTLs are systematically reviewed in the context of organic photovoltaics, from synthesis approaches to device performance. Different approaches for further enhancing the performance of solution-based metal oxide CTLs are also discussed, which may push the future development of this exciting field.

  14. Single water entropy: hydrophobic crossover and application to drug binding.

    Science.gov (United States)

    Sasikala, Wilbee D; Mukherjee, Arnab

    2014-09-11

    Entropy of water plays an important role in both chemical and biological processes e.g. hydrophobic effect, molecular recognition etc. Here we use a new approach to calculate translational and rotational entropy of the individual water molecules around different hydrophobic and charged solutes. We show that for small hydrophobic solutes, the translational and rotational entropies of each water molecule increase as a function of its distance from the solute reaching finally to a constant bulk value. As the size of the solute increases (0.746 nm), the behavior of the translational entropy is opposite; water molecules closest to the solute have higher entropy that reduces with distance from the solute. This indicates that there is a crossover in translational entropy of water molecules around hydrophobic solutes from negative to positive values as the size of the solute is increased. Rotational entropy of water molecules around hydrophobic solutes for all sizes increases with distance from the solute, indicating the absence of crossover in rotational entropy. This makes the crossover in total entropy (translation + rotation) of water molecule happen at much larger size (>1.5 nm) for hydrophobic solutes. Translational entropy of single water molecule scales logarithmically (Str(QH) = C + kB ln V), with the volume V obtained from the ellipsoid of inertia. We further discuss the origin of higher entropy of water around water and show the possibility of recovering the entropy loss of some hypothetical solutes. The results obtained are helpful to understand water entropy behavior around various hydrophobic and charged environments within biomolecules. Finally, we show how our approach can be used to calculate the entropy of the individual water molecules in a protein cavity that may be replaced during ligand binding.

  15. Experimental determination of the temperature dependence of water activities for a selection of aqueous organic solutions

    Directory of Open Access Journals (Sweden)

    G. Ganbavale

    2014-05-01

    Full Text Available This work presents experimental data of the temperature dependence of water activity in aqueous organic solutions relevant for tropospheric conditions (200–273 K. Water activity (aw at low temperatures (T is a crucial parameter for predicting homogeneous ice nucleation. We investigated temperature dependent water activities, ice freezing and melting temperatures of solutions, and vapour pressures of a selection of atmospherically relevant aqueous organic systems. To measure aw over a wide composition range and with a focus on low temperatures, we use various aw measurement techniques and instruments: a dew point water activity meter, an electrodynamic balance (EDB, differential scanning calorimetry (DSC, and a setup to measure the total gas phase pressure at equilibrium over aqueous solutions. Water activity measurements were performed for aqueous multicomponent and multifunctional organic mixtures containing the functional groups typically found in atmospheric organic aerosols, such as hydroxyl, carboxyl, ketone, ether, ester, and aromatic groups. The aqueous organic systems studied at several fixed compositions over a considerable temperature range differ significantly in their temperature dependence. Aqueous organic systems of 1,4-butanediol and methoxyacetic acid show a moderate decrease in aw with decreasing temperature. The aqueous M5 system (a multicomponent system containing five different dicarboxylic acids and aqueous 2-(2-ethoxyethoxyethanol solutions both show a strong increase of water activity with decreasing temperature at high solute concentrations for TTaw can be reversed at low temperatures and that linear extrapolations of high temperature data may lead to erroneous predictions. To avoid this, experimentally determined aw at low temperature are needed to improve thermodynamic models towards lower temperatures and for improved predictions of the ice nucleation ability of organic–water systems.

  16. Performance of Hydrophobic Associating Water-solute Polymer/Surfactant System%疏水缔合聚合物/表面活性剂二元体系性能研究

    Institute of Scientific and Technical Information of China (English)

    曹伟佳; 卢祥国; 苏鑫; 杨怀军; 张杰

    2016-01-01

    of Dagang oilfield and the poor development effect of water flooding,the feasibility of the application of hydrophobic associating polymer/surfactant displacement system was probed. The dimension of polymer molecular coil Dh,interfacial tension between the crude oil and the hydrophobic associating polymer AP-P7 solution or“polymer/surfactant”displacement system,compounded of AP-P7 and nonionic surfactant Guan 109PS985,and their influential factors were studied under the experimental conditions,andβ-cyclodextrin(β-cd) was used as the regulator to improve the suitability of polymer with oil reservoir,also the EOR mechanism of polymer flooding and“polymer/surfactant”displacement system in high viscosity and high condensate reservoirs was analyzed. The results showed that,β-cd could change the molecular morphological structure of the hydrophobic associating polymer,and make the matching of the polymer structure and core pore throat stronger,resulting in the reduction of the blockage. The viscosity hydrophobic associating polymer solution and“polymer/surfactant”system prepared with soft water,increased by 35.2%and 20.2%compared to that of the inject water,the viscosity of the polymer solution at the concentration of 2000 mg/L prepared with injected water and soft water, respectively,were 223.4 mPa.s and 302.5 mPa·s,When adding 700 mg/L ofβ-cd,the viscosity decreased to be of 26.5 mPa·s and 35.3 mPa·s,respectively,which indicated that the addition of theβ-cd made the viscosity of AP-P7 solutions decrease obviously. When the concentration of β-cd increased from 10 mg/L to 700 mg/L,the Dh of AP-P7 decreased from 235 nm to 155 nm. In addition,when the concentration ofβ-cd increased from 10 mg/L to 700 mg/L or the concentration of Ca2+and Mg2+decreased from 508 mg/L to 0,the interfacial tension between the polymer system and the simulated reduced to some degree. The 2000 mg/L polymer solution containingβ-cd was injected into the core with permeability

  17. Failure analysis in ITO-free all-solution processed organic solar cells

    NARCIS (Netherlands)

    Galagan, Y.; Eggenhuisen, T.M.; Coenen, M.J.J.; Biezemans, A.F.K.V.; Verhees, W.J.H.; Veenstra, S.C.; Groen, W.A.; Andriessen, R.; Janssen, R.A.J.

    2015-01-01

    In this paper we discuss a problem-solving methodology and present guidance for troubleshooting defects in ITO-free all-solution processed organic solar cells with an inverted cell architecture. A systematic approach for identifying the main causes of failures in devices is presented. Comprehensive

  18. Complementary circuits based on solution processed low-voltage organic field-effect transistors

    NARCIS (Netherlands)

    Ball, James M.; Wöbkenberg, Paul H.; Kooistra, Floris B.; Hummelen, Jan C.; Leeuw, Dago M. de; Bradley, Donal D.C.; Anthopoulos, Thomas D.

    2009-01-01

    The field of organic electronics is advancing quickly towards ultra low-cost, low-end applications and is expected to provide the necessary technology required for flexible/printed electronics. Here we address the need for solution processed low-voltage complementary logic in order to reduce power c

  19. Effect of dissolved organic matter composition on metal speciation in soil solutions

    NARCIS (Netherlands)

    Ren, Zong Ling; Tella, Marie; Bravin, M.N.; Comans, R.N.J.; Dai, Jun; Garnier, Jean Marie; Sivry, Yann; Doelsch, Emmanuel; Straathof, Angela; Benedetti, M.F.

    2015-01-01

    Knowledge of the speciation of heavy metals and the role of dissolved organic matter (DOM) in soil solution is a key to understand metal mobility and ecotoxicity. In this study, soil column-Donnan membrane technique (SC-DMT) was used to measure metal speciation of Cd, Cu, Ni, Pb, and Zn in eighte

  20. Organic-Inorganic Hybrid Solution-Processed H-2-Evolving Photocathodes

    NARCIS (Netherlands)

    Lai, Lai-Hung; Gomulya, Widianta; Berghuis, Matthijs; Protesescu, Loredana; Detz, Remko J.; Reek, Joost N. H.; Kovalenko, Maksym V.; Loi, Maria A.

    2015-01-01

    Here we report for the first time an H-2-evolving photocathode fabricated by a solution-processed organic inorganic hybrid composed of CdSe and P3HT. The CdSe:P3HT (10:1 (w/w)) hybrid bulk heterojunction treated with 1,2-ethanedithiol (EDT) showed efficient water reduction and hydrogen generation. A

  1. Failure analysis in ITO-free all-solution processed organic solar cells

    NARCIS (Netherlands)

    Galagan, Y.; Eggenhuisen, T.M.; Coenen, M.J.J.; Biezemans, A.F.K.V.; Verhees, W.J.H.; Veenstra, S.C.; Groen, W.A.; Andriessen, R.; Janssen, R.A.J.

    2015-01-01

    In this paper we discuss a problem-solving methodology and present guidance for troubleshooting defects in ITO-free all-solution processed organic solar cells with an inverted cell architecture. A systematic approach for identifying the main causes of failures in devices is presented. Comprehensive

  2. The recognition unit of FIBCD1 organizes into a noncovalently linked tetrameric structure and uses a hydrophobic funnel (S1) for acetyl group recognition

    DEFF Research Database (Denmark)

    Thomsen, Theresa; Moeller, Jesper B; Schlosser, Anders

    2010-01-01

    We have recently identified FIBCD1 (Fibrinogen C domain containing 1) as a type II transmembrane endocytic receptor located primarily in the intestinal brush border. The ectodomain of FIBCD1 comprises a coiled coil, a polycationic region, and a C-terminal FReD (fibrinogen-related domain) that ass......We have recently identified FIBCD1 (Fibrinogen C domain containing 1) as a type II transmembrane endocytic receptor located primarily in the intestinal brush border. The ectodomain of FIBCD1 comprises a coiled coil, a polycationic region, and a C-terminal FReD (fibrinogen-related domain......) that assembles into disulfide-linked homotetramers. The FIBCD1-FReD binds Ca(2+) dependently to acetylated structures like chitin, N-acetylated carbohydrates, and amino acids. FReDs are present in diverse innate immune pattern recognition proteins including the ficolins and horseshoe crab TL5A. Here, we use...... combined with site-directed mutagenesis to define the binding site involved in the interaction of FIBCD1 with acetylated structures. We show that mutations of central residues (A432V and H415G) in the hydrophobic funnel (S1) abolish the binding of FIBCD1 to acetylated bovine serum albumin and chitin...

  3. The effect of enhancing the hydrophobicity of OMMT on the characteristics of PMMA/OMMT nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Yamagata, Shuichi, E-mail: shuic@den.hokudai.ac.jp [Department of Orthodontics, Graduate School of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586 (Japan); Hamba, Yusuke [Department of Orthodontics, Graduate School of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586 (Japan); Akasaka, Tsukasa [Department of Biomedical Materials and Engineering, Graduate School of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586 (Japan); Ushijima, Natsumi [Support Section for Education and Research, Graduate School of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586 (Japan); Uo, Motohiro [Advanced Biomaterials, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549 (Japan); Iida, Junichiro [Department of Orthodontics, Graduate School of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586 (Japan); Watari, Fumio [Department of Biomedical Materials and Engineering, Graduate School of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586 (Japan)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer PMMA/OMMT nanocomposites were fabricated using a solution intercalation method. Black-Right-Pointing-Pointer The silicate platelets were largely well dispersed independent of the hydrophobicity. Black-Right-Pointing-Pointer The partially exfoliation of the silicate layers were observed. Black-Right-Pointing-Pointer The flexural modulus of the nanocomposites increased favorably. Black-Right-Pointing-Pointer The strain at breakage of the nanocomposites remained suitable for our use. - Abstract: Transparent poly(methyl methacrylate)/organically modified montmorillonite (PMMA/OMMT) nanocomposites were fabricated using a solution intercalation method. Two grades of OMMT modified with quaternary alkylammonium ions and containing different amounts of organic matter, NZ70 and NX, were used. X-ray diffraction patterns showed that the peaks regarded as a (0 0 1) d-spacing and a second peak were shifted toward lower 2{theta} values, implying the expansion or the partial exfoliation of the silicate layers, respectively. TEM images showed that the silicate platelets were largely well dispersed independent of the hydrophobicity, although some aggregates were observed. The flexural modulus of the PMMA/OMMT nanocomposites increased favorably with an increasing amount of OMMT of either grade. However, only the NX displayed comparable strain at breakage to that of the PMMA. These results suggest that the highly hydrophobic grade NX shows great promise for use in nanocomposites made via solution intercalation.

  4. Transient cavities in liquids and the nature of the hydrophobic effect

    Science.gov (United States)

    Pohorille, A.

    1998-01-01

    The size distributions of transient cavities in water and organic liquids, obtained from computer simulations, have provided a new means to analyze the nature of the hydrophobic effect and to evaluate the adequacy of different analytical models of this effect. The poor solubility of non-polar solutes in water is attributed to a low probability of finding in water cavities of atomic and molecular size. It has been shown that water applies more force per unit area of cavity surface than do hydrocarbon liquids. Models that successfully capture the main characteristics of the hydrophobic effect must at least include information about the density and the radial distribution of oxygen atoms in liquid water. One such model, quantitatively accurate for molecular solutes of arbitrary shape, is presented.

  5. Fluoroalkyl and alkyl chains have similar hydrophobicities in binding to the "hydrophobic wall" of carbonic anhydrase.

    Science.gov (United States)

    Mecinović, Jasmin; Snyder, Phillip W; Mirica, Katherine A; Bai, Serena; Mack, Eric T; Kwant, Richard L; Moustakas, Demetri T; Héroux, Annie; Whitesides, George M

    2011-09-07

    The hydrophobic effect, the free-energetically favorable association of nonpolar solutes in water, makes a dominant contribution to binding of many systems of ligands and proteins. The objective of this study was to examine the hydrophobic effect in biomolecular recognition using two chemically different but structurally similar hydrophobic groups, aliphatic hydrocarbons and aliphatic fluorocarbons, and to determine whether the hydrophobicity of the two groups could be distinguished by thermodynamic and biostructural analysis. This paper uses isothermal titration calorimetry (ITC) to examine the thermodynamics of binding of benzenesulfonamides substituted in the para position with alkyl and fluoroalkyl chains (H(2)NSO(2)C(6)H(4)-CONHCH(2)(CX(2))(n)CX(3), n = 0-4, X = H, F) to human carbonic anhydrase II (HCA II). Both alkyl and fluoroalkyl substituents contribute favorably to the enthalpy and the entropy of binding; these contributions increase as the length of chain of the hydrophobic substituent increases. Crystallography of the protein-ligand complexes indicates that the benzenesulfonamide groups of all ligands examined bind with similar geometry, that the tail groups associate with the hydrophobic wall of HCA II (which is made up of the side chains of residues Phe131, Val135, Pro202, and Leu204), and that the structure of the protein is indistinguishable for all but one of the complexes (the longest member of the fluoroalkyl series). Analysis of the thermodynamics of binding as a function of structure is compatible with the hypothesis that hydrophobic binding of both alkyl and fluoroalkyl chains to hydrophobic surface of carbonic anhydrase is due primarily to the release of nonoptimally hydrogen-bonded water molecules that hydrate the binding cavity (including the hydrophobic wall) of HCA II and to the release of water molecules that surround the hydrophobic chain of the ligands. This study defines the balance of enthalpic and entropic contributions to the

  6. Hydrophobic sugar holograms

    Science.gov (United States)

    Mejias-Brizuela, N. Y.; Olivares-Pérez, A.; Páez-Trujillo, G.; Hernández-Garay, M. P.; Fontanilla-Urdaneta, R.; Fuentes-Tapia, I.

    2008-02-01

    The sugar matrix is used to record of phase holograms; it was modified with the purpose of obtaining a hydrophobic material to improve the stability of the registered image and to stimulate the photosensitivity of the sugar. The new material is formed by a sugar, pectin and vanillin dissolution. The diffraction efficiency parameter increases in comparison with only the sugar matrix, obtaining already of 10%.

  7. Effects of Organic Corrosion Inhibitor and Chloride Ion Concentration on Steel Depassivation and Repassivation in Solution

    Institute of Scientific and Technical Information of China (English)

    WANG Zixiao; YU Lei; LIU Zhiyong; SONG Ning

    2015-01-01

    Effect of an organic corrosion inhibitor (OCI) named PCI-2014 added in chloride solution on the critical chlo-ride concentration of mild steel depassivation and the critical OCI concentrations for repairing the steel in different chlo-ride solution were investigated. The results show that the critical chloride concentration increases exponentially with raises of PCI-2014 concentration in the solution. Within a certain chloride ion concentration range, the critical PCI-2014 concentration for repairing the corroded steel is also increases exponentially with enhancement of chloride content in the solution. Atomic force microscopy images display the molecular particles of inhibitor are adsorbed on the steel surface and formed a protective layer. Analysis of X-ray photoelectron spectroscopy shows the chloride ions at the surface of steel are displaced by atoms or molecules of the inhibitor in chloride condition.

  8. Effects of Organic Corrosion Inhibitor and Chloride Ion Concentration on Steel Depassivation and Repassivation in Solution

    Institute of Scientific and Technical Information of China (English)

    WANG; Zixiao; YU; Lei; LIU; Zhiyong; SONG; Ning

    2015-01-01

    Effect of an organic corrosion inhibitor(OCI) named PCI-2014 added in chloride solution on the critical chloride concentration of mild steel depassivation and the critical OCI concentrations for repairing the steel in different chloride solution were investigated.The results show that the critical chloride concentration increases exponentially with raises of PCI-2014 concentration in the solution.Within a certain chloride ion concentration range,the critical PCI-2014 concentration for repairing the corroded steel is also increases exponentially with enhancement of chloride content in the solution.Atomic force microscopy images display the molecular particles of inhibitor are adsorbed on the steel surface and formed a protective layer.Analysis of X-ray photoelectron spectroscopy shows the chloride ions at the surface of steel are displaced by atoms or molecules of the inhibitor in chloride condition.

  9. The solubilities of significant organic compounds in HLW tanks upernate solutions - FY 1997 progress report

    Energy Technology Data Exchange (ETDEWEB)

    Barney, G.S.

    1997-09-16

    The solubilities of seven sodium salts of organic acids that are thought to exist in high-level waste at the Hanford Site were measured in tank supernatant simulant solutions during FY 1997. This solubility information will be used to determine if these organic salts could exist in solid phases (saltcake or sludges) in the waste where they might react violently with the nitrate or nitrite salts present in the tanks. The solubility of sodium acetate was measured in simulated waste supernate solutions at 25C, 30C, 40C, and 50C that were both unsaturated and saturated with sodium nitrate. Solubilities of sodium glycolate, citrate, ethylenediaminetetraacetate (EDTA), nitrilotriacetate (NTA), formate, and oxalate were measured in simulated waste supernate solutions that were saturated with sodium nitrate. In addition, solubilities of sodium EDTA, citrate, glycolate, and NTA were measured in a complex waste matrix. The organic compounds were selected because they are expected to exist in relatively high concentrations in the tanks. The solubilities of sodium glycolate citrate, EDTA, NTA, and formate were high over the temperature and sodium hydroxide concentration ranges expected in the tanks. The solubility of sodium oxalate in solutions saturated with sodium nitrate were quite low. The presence of additional sodium in the waste simulant solutions that were saturated with sodium nitrate slightly lowered the solubilities of each of the organic salts. Solubilities were, however, high enough to prevent solid sodium salts of all the organic acids from precipitating from tank supernate solutions, except for sodium oxalate. The total organic carbon concentrations (TOC) of actual tank supernates are generally much lower than the TOC ranges for the simulated supernate solutions saturated (at the solubility limit) with the organic salts. This is true even if all the dissolved carbon in a given tank supernate is due to only one of these soluble compounds (an unlikely situation

  10. Exact solutions to the continuous-quality equation for soil organic matter turnover.

    Science.gov (United States)

    Bosatta, Ernesto; Agren, Göran I

    2003-09-07

    All living systems depend on transformations of elements between different states. In particular, the transformation of dead organic matter in the soil (SOM) by decomposers (microbes) releases elements incorporated in SOM and makes the elements available anew to plants. A major problem in analysing and describing this process is that SOM, as the result of the decomposer activity, is a mixture of a very large number of molecules with widely differing chemical and physical properties. The continuous-quality equation (CQE) is a general equation describing this complexity by assigning a continuous-quality variable to each carbon atom in SOM. The use of CQE has been impeded by its complicated mathematics. Here, we show by deriving exact solutions that, at least for some specific cases, there exist solutions to CQE. These exact solutions show that previous approximations have overestimated the rate by which litter decomposes and as a consequence underestimated steady state SOM amounts. The exact and approximate solutions also differ with respect to the parameter space in which they yield finite steady-state SOM amounts. The latter point is important because temperature is one of the parameters and climatic change may move the solution from a region of the parameter space with infinite steady-state SOM to a region of finite steady-state SOM, with potentially large changes in soil carbon stores. We also show that the solution satisfies the Chapman-Kolmogorov theorem. The importance of this is that it provides efficient algorithms for numerical solutions.

  11. Measurement and prediction of aromatic solute distribution coefficients for aqueous-organic solvent systems. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J.R.; Luthy, R.G.

    1984-06-01

    Experimental and modeling activities were performed to assess techniques for measurement and prediction of distribution coefficients for aromatic solutes between water and immiscible organic solvents. Experiments were performed to measure distribution coefficients in both clean water and wastewater systems, and to assess treatment of a wastewater by solvent extraction. The theoretical portions of this investigation were directed towards development of techniques for prediction of solute-solvent/water distribution coefficients. Experiments were performed to assess treatment of a phenolic-laden coal conversion wastewater by solvent extraction. The results showed that solvent extraction for recovery of phenolic material offered several wastewater processing advantages. Distribution coefficients were measured in clean water and wastewater systems for aromatic solutes of varying functionality with different solvent types. It was found that distribution coefficients for these compounds in clean water systems were not statistically different from distribution coefficients determined in a complex coal conversion process wastewater. These and other aromatic solute distribution coefficient data were employed for evaluation of modeling techniques for prediction of solute-solvent/water distribution coefficients. Eight solvents were selected in order to represent various chemical classes: toluene and benzene (aromatics), hexane and heptane (alkanes), n-octanol (alcohols), n-butyl acetate (esters), diisopropyl ether (ethers), and methylisobutyl ketone (ketones). The aromatic solutes included: nonpolar compounds such as benzene, toluene and naphthalene, phenolic compounds such as phenol, cresol and catechol, nitrogenous aromatics such as aniline, pyridine and aminonaphthalene, and other aromatic solutes such as naphthol, quinolinol and halogenated compounds. 100 references, 20 figures, 34 tables.

  12. STUDIES ON REVERSE OSMOSIS SEPARATION OF AQUEOUS ORGANIC SOLUTIONS BY PAA/PSF COMPOSITE MEMBRANE

    Institute of Scientific and Technical Information of China (English)

    Jun Fang; De-min Jia; Ji-cai Huang; Qun-hui Guo; Feng-lian Wu

    2000-01-01

    The reverse osmosis (RO) separation of aqueous organic solutions, such as alcohols, amines, aldehydes, acids,ketones, and esters etc., by PAA (polyacrylic acid)/PSF (polysulfone) composite membrane has been studied. It was found that the separation results for aliphatic alcohols, amines and aldehydes are satisfactory, the solute rejection (Ra) and the volume fluxes of solutions (Jr) for 1000 ppm ethanol, ethylamine and ethyl aldehyde are 66.2%, 61.0%, 84.0% and 0.90×alcohols, amines and aldehydes, and the Ra for n-amyl alcohol, n-butylamine and n-butyl aldehyde reached 94.3%, 88.6%and 96.0%, respectively. Satisfactory separation results (Ra>70%) for ketones, esters, phenols and polyols have been obtained with the PAA/PSF composite membrane. The effect of operating pressure on the properties of reverse osmosis has also been investigated. Analysis of experimental data with Spiegler-Kedem's transport model has been carried out and the membrane constants such as reflection coefficient σ, solute and hydraulic permeabilities ω and Lp for several organic solutes have been obtained.

  13. Heterogeneous nucleation promotes carrier transport in solution-processed organic field-effect transistors

    KAUST Repository

    Li, Ruipeng

    2012-09-04

    A new way to investigate and control the growth of solution-cast thin films is presented. The combination of in situ quartz crystal microbalance measurements with dissipation capabilities (QCM-D) and in situ grazing-incidence wide-angle X-ray scattering (GIWAXS) in an environmental chamber provides unique quantitative insights into the time-evolution of the concentration of the solution, the onset of nucleation, and the mode of growth of the organic semiconductor under varied drying conditions. It is demonstrated that careful control over the kinetics of solution drying enhances carrier transport significantly by promoting phase transformation predominantly via heterogeneous nucleation and sustained surface growth of a highly lamellar structure at the solid-liquid interface at the expense of homogeneous nucleation. A new way to investigate and control the growth of drop-cast thin films is presented. The solution-processing of small-molecule thin films of TIPS-pentacene is investigated using time-resolved techniques to reveal the mechanisms of nucleation and growth leading to solid film formation. By tuning the drying speed of the solution, the balance between surface and bulk growth modes is altered, thereby controlling the lamellar formation and tuning the carrier mobility in organic field-effect transistors Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Chemotaxis can provide biological organisms with good solutions to the travelling salesman problem

    Science.gov (United States)

    Reynolds, A. M.

    2011-05-01

    The ability to find good solutions to the traveling salesman problem can benefit some biological organisms. Bacterial infection would, for instance, be eradicated most promptly if cells of the immune system minimized the total distance they traveled when moving between bacteria. Similarly, foragers would maximize their net energy gain if the distance that they traveled between multiple dispersed prey items was minimized. The traveling salesman problem is one of the most intensively studied problems in combinatorial optimization. There are no efficient algorithms for even solving the problem approximately (within a guaranteed constant factor from the optimum) because the problem is nondeterministic polynomial time complete. The best approximate algorithms can typically find solutions within 1%-2% of the optimal, but these are computationally intensive and can not be implemented by biological organisms. Biological organisms could, in principle, implement the less efficient greedy nearest-neighbor algorithm, i.e., always move to the nearest surviving target. Implementation of this strategy does, however, require quite sophisticated cognitive abilities and prior knowledge of the target locations. Here, with the aid of numerical simulations, it is shown that biological organisms can simply use chemotaxis to solve, or at worst provide good solutions (comparable to those found by the greedy algorithm) to, the traveling salesman problem when the targets are sources of a chemoattractant and are modest in number (n < 10). This applies to neutrophils and macrophages in microbial defense and to some predators.

  15. A Solution-Based Temperature Sensor Using the Organic Compound CuTsPc

    Directory of Open Access Journals (Sweden)

    Shahino Mah Abdullah

    2014-06-01

    Full Text Available An electrochemical cell using an organic compound, copper (II phthalocyanine-tetrasulfonic acid tetrasodium salt (CuTsPc, has been fabricated and investigated as a solution-based temperature sensor. The capacitance and resistance of the ITO/CuTsPc solution/ITO chemical cell has been characterized as a function of temperature in the temperature range of 25–80 °C. A linear response with minimal hysteresis is observed. The fabricated temperature sensor has shown high consistency and sensitive response towards a specific range of temperature values.

  16. Full-solution processed flexible organic solar cells using low-cost printable copper electrodes.

    Science.gov (United States)

    Li, Kan; Zhen, Hongyu; Niu, Liyong; Fang, Xu; Zhang, Yaokang; Guo, Ruisheng; Yu, You; Yan, Feng; Li, Haifeng; Zheng, Zijian

    2014-11-12

    Full-solution-processed flexible organic solar cells (OSCs) are fabricated using low-cost and high-quality printable Cu electrodes, which achieve a power conversion efficiency as high as 2.77% and show remarkable stability upon 1000 bending cycles. This device performance is thought to be the best among all full-solution-processed OSCs reported in the literature using the same active materials. This printed Cu electrode is promising for application in roll-to-roll fabrication of flexible OSCs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Assembly of Hydrophobically Modified Poly(acrylic acid) with Cyclodextrins%Assembly of Hydrophobically Modified Poly(acrylic acid) with Cyclodextrins

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Hydrophobically modified poly(acrylic acid)s (HMPAA) with alkyl (C12 or C18) substitution degree ranging from 3% to 10% were synthesized. Their rheological properties in aqueous solutions can be controlled by adding native cyclodextrins (CD) and surfactant SDS. Upon addition of CD, the viscosity of HMPAA solution was reduced significantly because of the destruction of hydrophobic associations by capping the hydrophobic alkyl groups by CD due to the host-guest complexation.

  18. Solution based zinc tin oxide TFTs: the dual role of the organic solvent

    Science.gov (United States)

    Salgueiro, Daniela; Kiazadeh, Asal; Branquinho, Rita; Santos, Lídia; Barquinha, Pedro; Martins, Rodrigo; Fortunato, Elvira

    2017-02-01

    Chemical solution deposition is a low cost, scalable and high performance technique to obtain metal oxide thin films. Recently, solution combustion synthesis has been introduced as a chemical route to reduce the processing temperature. This synthesis method takes advantage of the chemistry of the precursors as a source of energy for localized heating. According to the combustion chemistry some organic solvents can have a dual role in the reaction, acting both as solvent and fuel. In this work, we studied the role of 2-methoxyethanol in solution based synthesis of ZTO thin films and its influence on the performance of ZTO TFTs. The thermal behaviour of ZTO precursor solutions confirmed that 2-methoxyethanol acts simultaneously as a solvent and fuel, replacing the fuel function of urea. The electrical characterization of the solution based ZTO TFTs showed a slightly better performance and lower variability under positive gate bias stress when urea was not used as fuel, confirming that the excess fuel contributes negatively to the device operation and stability. Solution based ZTO TFTs demonstrated a low hysteresis (ΔV  =  -0.3 V) and a saturation mobility of 4-5 cm2 V-1 s-1.

  19. Heterogeneous Ice Nucleation During Ozonolysis of Organic Thin Films on Aqueous Solution Droplets

    Science.gov (United States)

    Wicks, G.; Cantrell, W.

    2005-12-01

    The mechanism by which ice is created affects cloud properties and processes. Although homogeneous ice nucleation is reasonably well understood, both experimentally and theoretically, heterogeneous ice nucleation is not. Since deep convection in the tropics lofts organic materials high into the atmosphere, it is important to achieve an understanding of heterogeneous nucleation by these materials and how it affects cirrus cloud formation. Sources of atmospheric organic compounds include combustion, biomass burning, emissions from vegetation, and sea spray which contains organic material from the ocean's surface. Fatty acids such as stearic acid and oleic acid are common organic constituents. The reaction of oleic acid with atmospheric ozone has recently become a model for understanding how atmospheric oxidation processes affect organic particles. Over the past six years, more than twenty publications have described reactive uptake coefficients, primary products, secondary reactions, mechanisms, and other aspects of this oxidation. With this background information in mind, we built an ozonolysis apparatus in tandem with a solution drop freezer to study the freezing point of 10-microliter, 0.25 M sodium chloride solution droplets coated with thin layers of 18-carbon fatty acids or alcohols. We determined the freezing points before and after ozonolysis for solution droplets coated with stearic acid, oleic acid, cis-13-octadecenoic acid, oleyl alcohol, and 1-octadecanol. During the experiments, temperature cycling was controlled by a computer-driven temperature controller. Results showed little change in mean freezing temperature before and after ozonolysis for all of the organic compounds studied except oleyl alcohol. The lack of a significant temperature change for oleic acid may be good news for atmospheric modelers since the well-studied reaction of ozone with oleic acid is known to give a complex mixture of products.

  20. Bioaccessible Porosity: A new approach to assess residual contamination after bioremediation of hydrophobic organic compounds in sub-surface microporous environments

    Science.gov (United States)

    Akbari, A.; Ghoshal, S.

    2016-12-01

    We define a new parameter, "bioaccessible porosity", the fraction of aggregate volume accessible to soil bacteria, towards a priori assessment of hydrocarbon bioremediation end points. Microbial uptake of poorly soluble hydrocarbons occurs through direct uptake or micellar solubilzation/emulsification associated with biosurfactant production, and requires close proximity of bacteria and hydrocarbon phase. In subsurface microporous environments, bioremediation rates are attenuated when residual hydrophobic contamination is entrapped in sterically restrictive environments which is not accessible to soil bacteria. This study presents new approaches for characterization of the microstructure of porous media and as well, the ability of indigenous hydrocarbon degraders to access to a range of pore sizes. Bacterial access to poorly soluble hydrocarbons in soil micro pores were simulated with bioreactors with membranes with different pore sizes containing the hydrocarbon degrading bacteria, Dietzia maris. D. maris is Gram-positive, and nonmotile that we isolated as the major hydrocarbon degrader from a fine-grained, weathered, hydrocarbon-contaminated site soil. Under nutritional stress, planktonic D. maris cells were aggregated and accessed 5 µm but not 3 µm and smaller pores. However, when hexadecane was available at the pore mouth, D. maris colonized the pore mouth, and accessed pores as small as 0.4 µm. This suggests bacterial accessibility to different pore sizes is regulated by nutritional conditions. A combination of X-ray micro-CT scanning, gas adsorption and mercury intrusion porosimetry was used to characterize the range of pore sizes of soil aggregates. In case of the studied contaminated soil, the bioaccessible porosity were determined as 25% , 27% and 29% (assuming 4, 1, 0.4 µm respectively as accessibility criteria), and about 2.7% of aggregate volume was attributed to 0.006-0.4 µm pores. The 2% aggregate volume at an assumed saturation of 10% could

  1. Sorption of organic cations to phyllosilicate clay minerals: CEC-normalization, salt dependency, and the role of electrostatic and hydrophobic effects.

    Science.gov (United States)

    Droge, Steven T J; Goss, Kai-Uwe

    2013-12-17

    Sorption to the phyllosilicate clay minerals Illite, kaolinite, and bentonite has been studied for a wide variety of organic cations using a flow-through method with fully aqueous medium as the eluent. Linear isotherms were observed at concentrations below 10% of the cation-exchange capacity (CEC) for Illite and kaolinite and below 1 mmol/kg (<1% CEC) for bentonite. Sorption to clays was strongly influenced by the electrolyte composition of the eluent but with a consistent trend for a diverse set of compounds on all clays, thus allowing for empirical correction factors. When sorption affinities for a given compound to a given clay are normalized to the CEC of the clay, the differences in sorption affinities between clays are reduced to less than 0.5 log units for most compounds. Although CEC-normalized sorption of quaternary ammonium compounds to clay was up to 10-fold higher than CEC-normalized sorption to soil organic matter, CEC-normalized sorption for most compounds was comparable between clays and soil organic matter. The clay fraction is thus a potentially relevant sorption phase for organic cations in many soils. The sorption data for organic cations to clay showed several regular trends with molecular structure but also showed quite a few systematic effects that we cannot explain. A model on the basis of the molecular size and charge density at the ionized nitrogen is used here as a tool to obtain benchmark values that elucidate the effect of specific polar moieties on the sorption affinity.

  2. Solution-processed organic tandem solar cells with power conversion efficiencies >12%

    Science.gov (United States)

    Li, Miaomiao; Gao, Ke; Wan, Xiangjian; Zhang, Qian; Kan, Bin; Xia, Ruoxi; Liu, Feng; Yang, Xuan; Feng, Huanran; Ni, Wang; Wang, Yunchuang; Peng, Jiajun; Zhang, Hongtao; Liang, Ziqi; Yip, Hin-Lap; Peng, Xiaobin; Cao, Yong; Chen, Yongsheng

    2016-12-01

    An effective way to improve the power conversion efficiency of organic solar cells is to use a tandem architecture consisting of two subcells, so that a broader part of the solar spectrum can be used and the thermalization loss of photon energy can be minimized. For a tandem cell to work well, it is important for the subcells to have complementary absorption characteristics and generate high and balanced (matched) currents. This requires a rather challenging effort to design and select suitable active materials for use in the subcells. Here, we report a high-performance solution-processed, tandem solar cell based on the small molecules DR3TSBDT and DPPEZnP-TBO, which offer efficient, complementary absorption when used as electron donor materials in the front and rear subcells, respectively. Optimized devices achieve a power conversion efficiency of 12.50% (verified 12.70%), which represents a new level of capability for solution-processed, organic solar cells.

  3. TAM-based external factors related to ERP solutions acceptance in organizations

    Directory of Open Access Journals (Sweden)

    Simona Zabukovsek

    2013-01-01

    Full Text Available To improve the efficiency and effectiveness of ERP solutions use, understanding of critical success factors of ERP solutions assimilation in organizations is crucial. The technology acceptance model (TAM proposed by Davis (1989 has been the most widely used model for researching user acceptance and usage of IT/IS. The purpose of this paper is to extend the original TAM with groups of external factors which impact actual ERP system use. First, we focus on ERP system use in companies’ maturity phase. Second, we expose and examine three groups of external factors which influence ERP usage. The model was empirically tested using data collected from a survey of ERP users in 44 organizations. Survey data have been collected from ERP users who have been exposed to an ERP system which has operated for more than one year. The proposed research model was analyzed using the PLS approach.

  4. Fully solution-processed organic solar cells on metal foil substrates

    KAUST Repository

    Gaynor, Whitney

    2009-08-19

    We demonstrate fully solution-processed organic photovoltaic cells on metal foil substrates with power conversion efficiencies similar to those obtained in devices on transparent substrates. The cells are based on the regioregular poly- (3-hexylthiophene) and C61 butyric acid methyl ester bulk heterojunction system. The bottom electrode is a silver film whose workfunction is lowered by Cs2CO3 using spin-coating to serve as a cathode. The transparent top anode consists of a conductive polymer in combination with a solution-processed silver nanowire mesh that is laminated onto the devices. Each layer of the device, including the transparent electrode, is fabricated from solution, giving rise to the possibility of completely printed solar cells on low-cost substrates.

  5. Marine snow, organic solute plumes, and optimal chemosensory behavior of bacteria

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Jackson, G.A.

    2001-01-01

    Leaking organic solutes form an elongated plume in the wake of a sinking aggregate. These solutes may both be assimilated by suspended bacteria and guide bacteria with chemokinetic swimming behavior toward the aggregate. We used modifications of previously published models of the flow...... and concentration fields around sinking aggregates and of chemokinetic behavior of bacteria to identify the behavior that optimizes aggregate colonization and plume utilization. The optimal solution is governed by physical constraints and is a trade off between a high sensitivity to chemical signals and a long...... signal integration time. For a run-and-tumble swimming behavior, the predicted tumbling frequency is between 1 and 10 s(-1), similar to that reported for marine bacteria. The predicted optimal sensitivity to chemical signals is similar to or greater than that known for Escherichia coli. The optimal...

  6. Characterization of Skeletonema costatum Intracellular Organic Matter and Study of Nanomechanical Properties under Different Solution Conditions

    KAUST Repository

    Gutierrez, Leonardo

    2016-06-17

    In the current investigation, a rigorous characterization of the high molecular weight (HMW) compounds of Skeletonema costatum (SKC) intracellular organic matter (IOM), including nanomechanical properties, was conducted. HMW SKC-IOM was characterized as a mixture of polysaccharides, proteins, and lipids. Atomic force microscopy (AFM) provided crucial information of this isolate at a nanoscale resolution. HMW SKC-IOM showed highly responsive to solution chemistry: fully extended chains at low ionic strength, and compressing structures with increasing electrolyte concentration in solution. Interestingly, two regions of different nanomechanical properties were observed: (a) Region #1: located farther from the substrate and showing extended polymeric chains, and (b) Region #2: located <10 nm above the substrate and presenting compressed structures. The polymer length, polymer grafting density, and compressibility of these two regions were highly influenced by solution conditions. Results suggest that steric interactions originating from HMW SKC-IOM polymeric structure would be a dominant interacting mechanism with surfaces. The current investigation has successfully applied models of polymer physics to describe the complex HMW SKC-IOM structural conformation at different solution conditions. The detailed methodology presented provides a tool to characterize and understand biopolymers interactions with surfaces, including filtration membranes, and can be extended to other environmentally relevant organic compounds.

  7. Microwave-induced carbon nanotubes catalytic degradation of organic pollutants in aqueous solution.

    Science.gov (United States)

    Chen, Jing; Xue, Shuang; Song, Youtao; Shen, Manli; Zhang, Zhaohong; Yuan, Tianxin; Tian, Fangyuan; Dionysiou, Dionysios D

    2016-06-05

    In this study, a new catalytic degradation technology using microwave induced carbon nanotubes (MW/CNTs) was proposed and applied in the treatment of organic pollutants in aqueous solution. The catalytic activity of three CNTs of 10-20nm, 20-40nm, and 40-60nm diameters were compared. The results showed that organic pollutants such as methyl orange (MO), methyl parathion (MP), sodium dodecyl benzene sulfonate (SDBS), bisphenol A (BPA), and methylene blue (MB) in aqueous solution could be degraded effectively and rapidly in MW/CNTs system. CNTs with diameter of 10-20nm exhibited the highest catalytic activity of the three CNTs under MW irradiation. Further, complete degradation was obtained using 10-20nm CNTs within 7.0min irradiation when 25mL MO solution (25mg/L), 1.2g/L catalyst dose, 450W, 2450MHz, and pH=6.0 were applied. The rate constants (k) for the degradation of SDBS, MB, MP, MO and BPA using 10-20nm CNTs/MW system were 0.726, 0.679, 0.463, 0.334 and 0.168min(-1), respectively. Therefore, this technology may have potential application for the treatment of targeted organic pollutants in wastewaters.

  8. Optimization of solution-processed oligothiophene:fullerene based organic solar cells by using solvent additives.

    Science.gov (United States)

    Schulz, Gisela L; Urdanpilleta, Marta; Fitzner, Roland; Brier, Eduard; Mena-Osteritz, Elena; Reinold, Egon; Bäuerle, Peter

    2013-01-01

    The optimization of solution-processed organic bulk-heterojunction solar cells with the acceptor-substituted quinquethiophene DCV5T-Bu 4 as donor in conjunction with PC61BM as acceptor is described. Power conversion efficiencies up to 3.0% and external quantum efficiencies up to 40% were obtained through the use of 1-chloronaphthalene as solvent additive in the fabrication of the photovoltaic devices. Furthermore, atomic force microscopy investigations of the photoactive layer gave insight into the distribution of donor and acceptor within the blend. The unique combination of solubility and thermal stability of DCV5T-Bu 4 also allows for fabrication of organic solar cells by vacuum deposition. Thus, we were able to perform a rare comparison of the device characteristics of the solution-processed DCV5T-Bu 4 :PC61BM solar cell with its vacuum-processed DCV5T-Bu 4 :C60 counterpart. Interestingly in this case, the efficiencies of the small-molecule organic solar cells prepared by using solution techniques are approaching those fabricated by using vacuum technology. This result is significant as vacuum-processed devices typically display much better performances in photovoltaic cells.

  9. Optimization of solution-processed oligothiophene:fullerene based organic solar cells by using solvent additives

    Directory of Open Access Journals (Sweden)

    Gisela L. Schulz

    2013-10-01

    Full Text Available The optimization of solution-processed organic bulk-heterojunction solar cells with the acceptor-substituted quinquethiophene DCV5T-Bu4 as donor in conjunction with PC61BM as acceptor is described. Power conversion efficiencies up to 3.0% and external quantum efficiencies up to 40% were obtained through the use of 1-chloronaphthalene as solvent additive in the fabrication of the photovoltaic devices. Furthermore, atomic force microscopy investigations of the photoactive layer gave insight into the distribution of donor and acceptor within the blend. The unique combination of solubility and thermal stability of DCV5T-Bu4 also allows for fabrication of organic solar cells by vacuum deposition. Thus, we were able to perform a rare comparison of the device characteristics of the solution-processed DCV5T-Bu4:PC61BM solar cell with its vacuum-processed DCV5T-Bu4:C60 counterpart. Interestingly in this case, the efficiencies of the small-molecule organic solar cells prepared by using solution techniques are approaching those fabricated by using vacuum technology. This result is significant as vacuum-processed devices typically display much better performances in photovoltaic cells.

  10. Electrosprayed molybdenum trioxide aqueous solution and its application in organic photovoltaic cells.

    Science.gov (United States)

    Suzuki, Katsumi; Fukuda, Takeshi; Liao, Yingjie

    2014-01-01

    A molybdenum trioxide thin film with smooth surface and uniform thickness was successfully achieved by an electrospray deposition method using an aqueous solution with a drastically low concentration of 0.05 wt%. Previous papers demonstrated that an additive solvent technique is useful for depositing the thin film by the electrospray deposition, and the high vapor pressure and a low surface tension of an additive solvent were found to be important factors. As a result, the smooth molybdenum trioxide thin film was obtained when the acetonitrile was used as the additive solvent. Furthermore, the vapor pressure of acetone is much higher than that of aqueous solution, and this indicates that the acetone is easily evaporated after spraying from the glass capillary. By optimizing a concentration of acetone in the molybdenum aqueous solution, a minimum root mean square roughness of the MoO3 thin film became 3.7 nm. In addition, an organic photovoltaic cell was also demonstrated using the molybdenum trioxide as a hole transport layer. Highest photoconversion efficiency was 1.72%, a value comparable to that using conventional thermal evaporation process even though the aqueous solution was used for the solution process. The photovonversion efficiency was not an optimized value, and the higher value can be achieved by optimizing the coating condition of the active layer.

  11. Electrosprayed molybdenum trioxide aqueous solution and its application in organic photovoltaic cells.

    Directory of Open Access Journals (Sweden)

    Katsumi Suzuki

    Full Text Available A molybdenum trioxide thin film with smooth surface and uniform thickness was successfully achieved by an electrospray deposition method using an aqueous solution with a drastically low concentration of 0.05 wt%. Previous papers demonstrated that an additive solvent technique is useful for depositing the thin film by the electrospray deposition, and the high vapor pressure and a low surface tension of an additive solvent were found to be important factors. As a result, the smooth molybdenum trioxide thin film was obtained when the acetonitrile was used as the additive solvent. Furthermore, the vapor pressure of acetone is much higher than that of aqueous solution, and this indicates that the acetone is easily evaporated after spraying from the glass capillary. By optimizing a concentration of acetone in the molybdenum aqueous solution, a minimum root mean square roughness of the MoO3 thin film became 3.7 nm. In addition, an organic photovoltaic cell was also demonstrated using the molybdenum trioxide as a hole transport layer. Highest photoconversion efficiency was 1.72%, a value comparable to that using conventional thermal evaporation process even though the aqueous solution was used for the solution process. The photovonversion efficiency was not an optimized value, and the higher value can be achieved by optimizing the coating condition of the active layer.

  12. Removal of organic matter from H2TaF7 solution by adsorption

    Institute of Scientific and Technical Information of China (English)

    LI Qing-gang; ZHOU Kang-gen; ZHANG Qi-xiu

    2005-01-01

    The removal of organic matter from H2TaF7 solution by adsorption was investigated in order to reduce the carbon content in the K2TaF7 crystal. Three kinds of adsorbent, LSA-5 resin, LSA-20 resin and active carbon were applied in the fixed bed respectively. Experimental results indicate that LAS-5 resin, LAS-20 resin, the mixture of LAS-5 resin and LAS-20 resin(with volume ratio of 1∶1), and the active carbon can all reduce chemical oxygen demand(COD) value of the H2TaF7 solution, and reduce consequently carbon content of K2TaF7 crystal to 0.001 0%0.001 5% from 0.002 5%0.003 0%. Comparing with the others, the active carbon is an approved adsorbent whose bed volumes of effluent reaches 70. In addition, there is a linear relationship between the COD value of H2TaF7 solution and the carbon content in K2TaF7 crystal, and the carbon content in K2TaF7 crystal decreases with the decreasing of COD value of H2TaF7 solution. When the COD value of H2TaF7 solution is lower than 7 mg/L, the carbon content in K2TaF7 crystal would decrease to less than 0.001 5%.

  13. Solution structure of the dimerization domain of the eukaryotic stalk P1/P2 complex reveals the structural organization of eukaryotic stalk complex.

    Science.gov (United States)

    Lee, Ka-Ming; Yu, Conny Wing-Heng; Chiu, Teddy Yu-Hin; Sze, Kong-Hung; Shaw, Pang-Chui; Wong, Kam-Bo

    2012-04-01

    The lateral ribosomal stalk is responsible for the kingdom-specific binding of translation factors and activation of GTP hydrolysis during protein synthesis. The eukaryotic stalk is composed of three acidic ribosomal proteins P0, P1 and P2. P0 binds two copies of P1/P2 hetero-dimers to form a pentameric P-complex. The structure of the eukaryotic stalk is currently not known. To provide a better understanding on the structural organization of eukaryotic stalk, we have determined the solution structure of the N-terminal dimerization domain (NTD) of P1/P2 hetero-dimer. Helix-1, -2 and -4 from each of the NTD-P1 and NTD-P2 form the dimeric interface that buries 2200 A(2) of solvent accessible surface area. In contrast to the symmetric P2 homo-dimer, P1/P2 hetero-dimer is asymmetric. Three conserved hydrophobic residues on the surface of NTD-P1 are replaced by charged residues in NTD-P2. Moreover, NTD-P1 has an extra turn in helix-1, which forms extensive intermolecular interactions with helix-1 and -4 of NTD-P2. Truncation of this extra turn of P1 abolished the formation of P1/P2 hetero-dimer. Systematic truncation studies suggest that P0 contains two spine-helices that each binds one copy of P1/P2 hetero-dimer. Modeling studies suggest that a large hydrophobic cavity, which can accommodate the loop between the spine-helices of P0, can be found on NTD-P1 but not on NTD-P2 when the helix-4 adopts an 'open' conformation. Based on the asymmetric properties of NTD-P1/NTD-P2, a structural model of the eukaryotic P-complex with P2/P1:P1/P2 topology is proposed.

  14. Persistent photocurrent (PPC) in solution-processed organic thin film transistors: Mechanisms of gate voltage control

    Science.gov (United States)

    Singh, Subhash; Mohapatra, Y. N.

    2016-07-01

    There is a growing need to understand mechanisms of photoresponse in devices based on organic semiconductor thin films and interfaces. The phenomenon of persistent photocurrent (PPC) has been systematically investigated in solution processed TIPS-Pentacene based organic thin film transistors (OTFTs) as an important example of an organic semiconductor material system. With increasing light intensity from dark to 385 mW/cm2, there is a significant shift in threshold voltage (VTh) while the filed-effect mobility remains unchanged. The OTFT shows large photoresponse under white light illumination due to exponential tail states with characteristic energy parameter of 86 meV. The photo-induced current is observed to persist even for several hours after turning the light off. To investigate the origin of PPC, its quenching mechanism is investigated by a variety of methods involving a combination of gate bias, illumination and temperature. We show that a coherent model of trap-charge induced carrier concentration is able to account for the quenching behavior. Analysis of isothermal transients using time-analyzed transient spectroscopy shows that the emission rates are activated and are also field enhanced due to Poole-Frankel effect. The results shed light on the nature, origin, and energetic distribution of the traps controlling PPC in solution processed organic semiconductors and their interfaces.

  15. Solution-printed organic semiconductor blends exhibiting transport properties on par with single crystals

    KAUST Repository

    Niazi, Muhammad R.

    2015-11-23

    Solution-printed organic semiconductors have emerged in recent years as promising contenders for roll-to-roll manufacturing of electronic and optoelectronic circuits. The stringent performance requirements for organic thin-film transistors (OTFTs) in terms of carrier mobility, switching speed, turn-on voltage and uniformity over large areas require performance currently achieved by organic single-crystal devices, but these suffer from scale-up challenges. Here we present a new method based on blade coating of a blend of conjugated small molecules and amorphous insulating polymers to produce OTFTs with consistently excellent performance characteristics (carrier mobility as high as 6.7 cm2 V−1 s−1, low threshold voltages of<1 V and low subthreshold swings <0.5 V dec−1). Our findings demonstrate that careful control over phase separation and crystallization can yield solution-printed polycrystalline organic semiconductor films with transport properties and other figures of merit on par with their single-crystal counterparts.

  16. Thorough removal of inorganic and organic mercury from aqueous solutions by adsorption on Lemna minor powder.

    Science.gov (United States)

    Li, Shun-Xing; Zheng, Feng-Ying; Yang, Huang; Ni, Jian-Cong

    2011-02-15

    The adsorption ability of duckweed (Lemna minor) powders for removing inorganic and organic mercury (methyl and ethyl mercury) has been studied using cold vapour atomic absorption spectrometry. The optimal adsorption conditions were: (a) the pH value of the solution 7.0 for inorganic and ethyl mercury, 9.0 for methyl mercury, and (b) equilibrium adsorption time 10, 20, and 40 min for inorganic mercury, methyl mercury, and ethyl mercury, respectively. After adsorption by L. minor powder for 40 min, when the initial concentrations of inorganic and organic mercury were under 12.0 μg L(-1) and 50.0 μg L(-1), respectively, the residual concentrations of mercury could meet the criterion of drinking water (1.0 μg L(-1)) and the permitted discharge limit of wastewater (10.0 μg L(-1)) set by China and USEPA, respectively. Thorough removal of both inorganic and organic mercury from aqueous solutions was reported for the first time. The significant adsorption sites were C-O-P and phosphate groups by the surface electrostatic interactions with aqueous inorganic and organic mercury cations, and then the selective adsorption was resulted from the strong chelating interaction between amine groups and mercury on the surface of L. minor cells.

  17. Aggregation behavior modulation of 1-dodecyl-3-methylimidazolium bromide by organic solvents in aqueous solution.

    Science.gov (United States)

    Wang, Jianji; Zhang, Lamei; Wang, Huiyong; Wu, Changzeng

    2011-05-05

    Material preparation in ionic liquids and environmental pollution control by ionic liquids are often closely dependent on the aggregation behavior of ionic liquids in solution. In the present work, conductivity, fluorescence probe, and dynamic light scattering techniques have been used to study the effect of organic solvents on the aggregation behavior of 1-dodecyl-3-methylimidazolium bromide in water. It was shown that the critical aggregation concentration (CAC), the ionization degree of the aggregates (α), and the standard Gibbs energy of aggregation (ΔG(m)°) of the ionic liquid increase, while its aggregation number (N(agg)) and aggregates' size decrease with increasing concentration of organic additives in water. These results have been discussed from the favorable interactions of alkyl chain of the ionic liquid with the mixed solvents. It is suggested that the solvophobic parameter, characterized quantitatively by Gibbs energy of transfer of hydrocarbon from gas into a given solvent, can be used to account for the effect of organic additives on the formation and growth of the ionic liquid aggregates in water. Aggregation behavior of ionic liquids in aqueous organic solutions can be modulated simply by the solvophobic parameters of hydrocarbon in the mixed solvents.

  18. Multi-solution processes of small molecule for flexible white organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Yu-Sheng, E-mail: ystsai@nfu.edu.tw [Institute of Electro-optical and Materials Science, National Formosa University, Yunlin 63201, Taiwan, ROC (China); Chittawanij, Apisit; Hong, Lin-Ann; Guo, Siou-Wei [Institute of Electro-optical and Materials Science, National Formosa University, Yunlin 63201, Taiwan, ROC (China); Wang, Ching-Chiun [Department of Solid State Lighting Technology, Mechanical and Systems Research Laboratories, Industrial Technology Research Institute, Hsinchu 31040, Taiwan, ROC (China); Juang, Fuh-Shyang [Institute of Electro-optical and Materials Science, National Formosa University, Yunlin 63201, Taiwan, ROC (China); Lai, Shih-Hsiang [Department of Solid State Lighting Technology, Mechanical and Systems Research Laboratories, Industrial Technology Research Institute, Hsinchu 31040, Taiwan, ROC (China); Lin, Yang-Ching [Institute of Electro-optical and Materials Science, National Formosa University, Yunlin 63201, Taiwan, ROC (China)

    2016-04-01

    Most small molecule organic light emitting diode (SM-OLED) device structures are made in one layer using solution-based processing because the solution is usually a high dissolvent material that easily attacks the layer below it. We demonstrate a simple and reliable stamping technique for fabricating multi-solution process flexible white SM-OLEDs. The structure is anode/spin-hole injection layer/spin-emitting layer/stamping-electron transport layer/cathode. Poly(di-methyl silane) (PDMS) stamp is used for transferring electron transport layer. An intermediate ultraviolet-ozone surface treatment is introduced to temporarily modify the PDMS stamp surface. Then, the solution-based electron transport layer film can therefore be uniformly formed on top of the PDMS surface. After that the electron transport layer film on the PDMS stamp is transfer-printed onto the emitting layer with suitable heating and pressing. A solution-based processing is successfully established to efficiently fabricate flexible white SM-OLEDs. The SM-OLEDs were obtained at the current density of 20 mA/cm{sup 2}, luminance of 1062 cd/m{sup 2}, current efficiency of 5.57 cd/A, and Commission internationale de l'éclairage coordinate of (0.32, 0.35). - Highlights: • All solution-processed small molecule materials (emitting layer, electron transport layer). • Poly(di-methylsilane) (PDMS) stamp is subsequently used for stamping transfer. • The flexible white SM-OLEDs are based on solution-processes with a low-cost method.

  19. Organic Light-Emitting Diodes on Solution-Processed Graphene Transparent Electrodes

    KAUST Repository

    Wu, Junbo

    2010-01-26

    Theoretical estimates indicate that graphene thin films can be used as transparent electrodes for thin-film devices such as solar cells and organic light-emitting diodes, with an unmatched combination of sheet resistance and transparency. We demonstrate organic light-emitting diodes with solution-processed graphene thin film transparent conductive anodes. The graphene electrodes were deposited on quartz substrates by spincoating of an aqueous dispersion of functionalized graphene, followed by a vacuum anneal step to reduce the sheet resistance. Small molecular weight organic materials and a metal cathode were directly deposited on the graphene anodes, resulting in devices with a performance comparable to control devices on indium-tin-oxide transparent anodes. The outcoupling efficiency of devices on graphene and indium-tin-oxide is nearly identical, in agreement with model predictions. © 2010 American Chemical Society.

  20. Photoinduced reactions between Pb3O4 and organic dyes in aqueous solution under visible light.

    Science.gov (United States)

    Zhou, Yangen; Long, Jinlin; Gu, Quan; Lin, Huaxiang; Lin, Huan; Wang, Xuxu

    2012-12-03

    Pb(3)O(4) could react with organic dyes in aqueous solution under visible light irradiation, in which Pb(3)O(4) was transformed into Pb(3)(CO(3))(2)(OH)(2) along with oxidation of the organic dyes. Cu(2+) has considerable effect on the reaction. In the presence of Cu(2+), MO (20 ppm) and RhB (10(-5) mol L(-1)) were completely degraded under visible light within 6 and 20 min, respectively, while both Pb(3)O(4) and Cu(2+) keep almost stable during photodegradation. The mechanisms of the reactions with and without Cu(2+) ions were studied. The photochemical system of Pb(3)O(4) cooperating with Cu(2+) ions is probably used for the treatment of organic pollutants in water under visible light.

  1. A General Method for Growing Two-Dimensional Crystals of Organic Semiconductors by "Solution Epitaxy".

    Science.gov (United States)

    Xu, Chunhui; He, Ping; Liu, Jie; Cui, Ajuan; Dong, Huanli; Zhen, Yonggang; Chen, Wei; Hu, Wenping

    2016-08-08

    Two-dimensional (2D) crystals of organic semiconductors (2DCOS) have attracted attention for large-area and low-cost flexible optoelectronics. However, growing large 2DCOS in controllable ways and transferring them onto technologically important substrates, remain key challenges. Herein we report a facile, general, and effective method to grow 2DCOS up to centimeter size which can be transferred to any substrate efficiently. The method named "solution epitaxy" involves two steps. The first is to self-assemble micrometer-sized 2DCOS on water surface. The second is epitaxial growth of them into millimeter or centimeter sized 2DCOS with thickness of several molecular layers. The general applicability of this method for the growth of 2DCOS is demonstrated by nine organic semiconductors with different molecular structures. Organic field-effect transistors (OFETs) based on the 2DCOS demonstrated high performance, confirming the high quality of the 2DCOS.

  2. Trends in soil solution dissolved organic carbon (DOC) concentrations across European forests

    Science.gov (United States)

    Camino-Serrano, Marta; Graf Pannatier, Elisabeth; Vicca, Sara; Luyssaert, Sebastiaan; Jonard, Mathieu; Ciais, Philippe; Guenet, Bertrand; Gielen, Bert; Peñuelas, Josep; Sardans, Jordi; Waldner, Peter; Etzold, Sophia; Cecchini, Guia; Clarke, Nicholas; Galić, Zoran; Gandois, Laure; Hansen, Karin; Johnson, Jim; Klinck, Uwe; Lachmanová, Zora; Lindroos, Antti-Jussi; Meesenburg, Henning; Nieminen, Tiina M.; Sanders, Tanja G. M.; Sawicka, Kasia; Seidling, Walter; Thimonier, Anne; Vanguelova, Elena; Verstraeten, Arne; Vesterdal, Lars; Janssens, Ivan A.

    2016-10-01

    Dissolved organic carbon (DOC) in surface waters is connected to DOC in soil solution through hydrological pathways. Therefore, it is expected that long-term dynamics of DOC in surface waters reflect DOC trends in soil solution. However, a multitude of site studies have failed so far to establish consistent trends in soil solution DOC, whereas increasing concentrations in European surface waters over the past decades appear to be the norm, possibly as a result of recovery from acidification. The objectives of this study were therefore to understand the long-term trends of soil solution DOC from a large number of European forests (ICP Forests Level II plots) and determine their main physico-chemical and biological controls. We applied trend analysis at two levels: (1) to the entire European dataset and (2) to the individual time series and related trends with plot characteristics, i.e., soil and vegetation properties, soil solution chemistry and atmospheric deposition loads. Analyses of the entire dataset showed an overall increasing trend in DOC concentrations in the organic layers, but, at individual plots and depths, there was no clear overall trend in soil solution DOC. The rate change in soil solution DOC ranged between -16.8 and +23 % yr-1 (median = +0.4 % yr-1) across Europe. The non-significant trends (40 %) outnumbered the increasing (35 %) and decreasing trends (25 %) across the 97 ICP Forests Level II sites. By means of multivariate statistics, we found increasing trends in DOC concentrations with increasing mean nitrate (NO3-) deposition and increasing trends in DOC concentrations with decreasing mean sulfate (SO42-) deposition, with the magnitude of these relationships depending on plot deposition history. While the attribution of increasing trends in DOC to the reduction of SO42- deposition could be confirmed in low to medium N deposition areas, in agreement with observations in surface waters, this was not the case in high N deposition areas. In

  3. Multiscale Molecular Simulation of Solution Processing of SMDPPEH: PCBM Small-Molecule Organic Solar Cells.

    Science.gov (United States)

    Lee, Cheng-Kuang; Pao, Chun-Wei

    2016-08-17

    Solution-processed small-molecule organic solar cells are a promising renewable energy source because of their low production cost, mechanical flexibility, and light weight relative to their pure inorganic counterparts. In this work, we developed a coarse-grained (CG) Gay-Berne ellipsoid molecular simulation model based on atomistic trajectories from all-atom molecular dynamics simulations of smaller system sizes to systematically study the nanomorphology of the SMDPPEH/PCBM/solvent ternary blend during solution processing, including the blade-coating process by applying external shear to the solution. With the significantly reduced overall system degrees of freedom and computational acceleration from GPU, we were able to go well beyond the limitation of conventional all-atom molecular simulations with a system size on the order of hundreds of nanometers with mesoscale molecular detail. Our simulations indicate that, similar to polymer solar cells, the optimal blending ratio in small-molecule organic solar cells must provide the highest specific interfacial area for efficient exciton dissociation, while retaining balanced hole/electron transport pathway percolation. We also reveal that blade-coating processes have a significant impact on nanomorphology. For given donor/acceptor blending ratios, applying an external shear force can effectively promote donor/acceptor phase segregation and stacking in the SMDPPEH domains. The present study demonstrated the capability of an ellipsoid-based coarse-grained model for studying the nanomorphology evolution of small-molecule organic solar cells during solution processing/blade-coating and provided links between fabrication protocols and device nanomorphologies.

  4. Tracking of the organic species during the synthesis of cobalt-based nanoparticles in non-aqueous solution

    Science.gov (United States)

    Staniuk, M.; Niederberger, M.; Koziej, D.

    2014-08-01

    In this work we investigate the organic products of the synthesis of Co-based nanoparticles in benzyl alcohol. Our GC and in situ IR studies provide the experimental proofs for the formation of benzaldehyde, toluene and isopropanol in the reaction solution. These organic products can be correlated with formation of cobalt-based nanoparticles with oxidation state from 0 to 3+. These results shine the light on the complexity of organic and inorganic reactions in solution during crystallization of nanoparticles.

  5. Necessity of capillary modes in a minimal model of nanoscale hydrophobic solvation

    Science.gov (United States)

    Vaikuntanathan, Suriyanarayanan; Rotskoff, Grant; Hudson, Alexander; Geissler, Phillip L.

    2016-01-01

    Modern theories of the hydrophobic effect highlight its dependence on length scale, emphasizing the importance of interfaces in the vicinity of sizable hydrophobes. We recently showed that a faithful treatment of such nanoscale interfaces requires careful attention to the statistics of capillary waves, with significant quantitative implications for the calculation of solvation thermodynamics. Here, we show that a coarse-grained lattice model like that of Chandler [Chandler D (2005) Nature 437(7059):640–647], when informed by this understanding, can capture a broad range of hydrophobic behaviors with striking accuracy. Specifically, we calculate probability distributions for microscopic density fluctuations that agree very well with results of atomistic simulations, even many SDs from the mean and even for probe volumes in highly heterogeneous environments. This accuracy is achieved without adjustment of free parameters, because the model is fully specified by well-known properties of liquid water. As examples of its utility, we compute the free-energy profile for a solute crossing the air–water interface, as well as the thermodynamic cost of evacuating the space between extended nanoscale surfaces. These calculations suggest that a highly reduced model for aqueous solvation can enable efficient multiscale modeling of spatial organization driven by hydrophobic and interfacial forces. PMID:26957607

  6. Necessity of capillary modes in a minimal model of nanoscale hydrophobic solvation.

    Science.gov (United States)

    Vaikuntanathan, Suriyanarayanan; Rotskoff, Grant; Hudson, Alexander; Geissler, Phillip L

    2016-04-19

    Modern theories of the hydrophobic effect highlight its dependence on length scale, emphasizing the importance of interfaces in the vicinity of sizable hydrophobes. We recently showed that a faithful treatment of such nanoscale interfaces requires careful attention to the statistics of capillary waves, with significant quantitative implications for the calculation of solvation thermodynamics. Here, we show that a coarse-grained lattice model like that of Chandler [Chandler D (2005)Nature437(7059):640-647], when informed by this understanding, can capture a broad range of hydrophobic behaviors with striking accuracy. Specifically, we calculate probability distributions for microscopic density fluctuations that agree very well with results of atomistic simulations, even many SDs from the mean and even for probe volumes in highly heterogeneous environments. This accuracy is achieved without adjustment of free parameters, because the model is fully specified by well-known properties of liquid water. As examples of its utility, we compute the free-energy profile for a solute crossing the air-water interface, as well as the thermodynamic cost of evacuating the space between extended nanoscale surfaces. These calculations suggest that a highly reduced model for aqueous solvation can enable efficient multiscale modeling of spatial organization driven by hydrophobic and interfacial forces.

  7. Microwave-induced carbon nanotubes catalytic degradation of organic pollutants in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jing; Xue, Shuang; Song, Youtao; Shen, Manli [School of Environment Science, Liaoning University, Shenyang 110036 (China); Zhang, Zhaohong, E-mail: lnuhjhx@163.com [School of Environment Science, Liaoning University, Shenyang 110036 (China); Yuan, Tianxin; Tian, Fangyuan [School of Environment Science, Liaoning University, Shenyang 110036 (China); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012 (United States)

    2016-06-05

    Highlights: • Microwave-induced CNTs-based catalytic degradation technology is developed. • Microwave catalytic activities of CNTs with different diameters are compared. • Organic pollutants with different structure can be degraded in MW/CNTs system. • The 10–20 nm CNTs shows the higher catalytic activity under MW irradiation. - Abstract: In this study, a new catalytic degradation technology using microwave induced carbon nanotubes (MW/CNTs) was proposed and applied in the treatment of organic pollutants in aqueous solution. The catalytic activity of three CNTs of 10–20 nm, 20–40 nm, and 40–60 nm diameters were compared. The results showed that organic pollutants such as methyl orange (MO), methyl parathion (MP), sodium dodecyl benzene sulfonate (SDBS), bisphenol A (BPA), and methylene blue (MB) in aqueous solution could be degraded effectively and rapidly in MW/CNTs system. CNTs with diameter of 10–20 nm exhibited the highest catalytic activity of the three CNTs under MW irradiation. Further, complete degradation was obtained using 10–20 nm CNTs within 7.0 min irradiation when 25 mL MO solution (25 mg/L), 1.2 g/L catalyst dose, 450 W, 2450 MHz, and pH = 6.0 were applied. The rate constants (k) for the degradation of SDBS, MB, MP, MO and BPA using 10–20 nm CNTs/MW system were 0.726, 0.679, 0.463, 0.334 and 0.168 min{sup −1}, respectively. Therefore, this technology may have potential application for the treatment of targeted organic pollutants in wastewaters.

  8. Sorption of four hydrophobic organic contaminants by biochars derived from maize straw, wood dust and swine manure at different pyrolytic temperatures.

    Science.gov (United States)

    Wang, Ziying; Han, Lanfang; Sun, Ke; Jin, Jie; Ro, Kyoung S; Libra, Judy A; Liu, Xitao; Xing, Baoshan

    2016-02-01

    Sorption behavior of acetochlor (ACE), dibutyl phthalate (DBP), 17α-Ethynyl estradiol (EE2) and phenanthrene (PHE) with biochars produced from three feedstocks (maize straw (MABs), pine wood dust (WDBs) and swine manure (SWBs)) at seven heat treatment temperatures (HTTs) was evaluated. The bulk polarity of these biochars declined with increasing HTT while the aromaticity and CO2-surface area (CO2-SA) rose. The surface OC contents of biochars were generally higher than bulk OC contents. The organic carbon (OC)-normalized CO2-SA (CO2-SA/OC) of biochars significantly correlated with the sorption coefficients (n and logK(oc)), suggesting that pore filling could dominate the sorption of tested sorbates. SWBs had higher logK(oc) values compared to MABs and WDBs, due to their higher ash contents. Additionally, the logK(oc) values for MABs was relatively greater than that for WDBs at low HTTs (≤400 °C), probably resulting from the higher CO2-SA/OC, ash contents and aromaticity of MABs. Surface polarity and the aliphatic C may dominate the sorption of WDBs obtained at relatively low HTTs (≤400 °C), while aromatic C affects the sorption of biochars at high HTTs. Results of this work aid to deepen our understanding of the sorption mechanisms, which is pivotal to wise utilization of biochars as sorbents for hazardous organic compounds.

  9. Solution-Processed Nanowire Coating for Light Management in Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    K. Tsuboi

    2012-01-01

    Full Text Available We report a novel light management approach based on solution-processed nanowire (NW coating for enhancing organic solar cell efficiency. A titanium dioxide (TiO2 NW dispersion was produced by electrospinning. The coatings with various coverage fractions were fabricated by a simple solution casting of a TiO2 NW dispersion. Reduced reflectivity was observed for the NW-coated glass slide. The bulk-heterojunction organic solar cells with the NW coating showed improved power conversion efficiencies (PCEs due to their antireflection and light trapping effects in the active layer. In addition, the PCE of the cell with the NW coating was improved compared with that without the NW coating for incident angles above 70° (increased by a maximum of 51.6% at an incident angle of 85°. These results indicate that solution-processed NW coating is a promising light management approach easily scalable and applicable to a wide range of devices, including solar cells.

  10. Low-Temperature Solution-Processed Gate Dielectrics for High-Performance Organic Thin Film Transistors

    Directory of Open Access Journals (Sweden)

    Jaekyun Kim

    2015-10-01

    Full Text Available A low-temperature solution-processed high-k gate dielectric layer for use in a high-performance solution-processed semiconducting polymer organic thin-film transistor (OTFT was demonstrated. Photochemical activation of sol-gel-derived AlOx films under 150 °C permitted the formation of a dense film with low leakage and relatively high dielectric-permittivity characteristics, which are almost comparable to the results yielded by the conventionally used vacuum deposition and high temperature annealing method. Octadecylphosphonic acid (ODPA self-assembled monolayer (SAM treatment of the AlOx was employed in order to realize high-performance (>0.4 cm2/Vs saturation mobility and low-operation-voltage (<5 V diketopyrrolopyrrole (DPP-based OTFTs on an ultra-thin polyimide film (3-μm thick. Thus, low-temperature photochemically-annealed solution-processed AlOx film with SAM layer is an attractive candidate as a dielectric-layer for use in high-performance organic TFTs operated at low voltages.

  11. Controllable lasing performance in solution-processed organic-inorganic hybrid perovskites.

    Science.gov (United States)

    Kao, Tsung Sheng; Chou, Yu-Hsun; Hong, Kuo-Bin; Huang, Jiong-Fu; Chou, Chun-Hsien; Kuo, Hao-Chung; Chen, Fang-Chung; Lu, Tien-Chang

    2016-11-03

    Solution-processed organic-inorganic perovskites are fascinating due to their remarkable photo-conversion efficiency and great potential in the cost-effective, versatile and large-scale manufacturing of optoelectronic devices. In this paper, we demonstrate that the perovskite nanocrystal sizes can be simply controlled by manipulating the precursor solution concentrations in a two-step sequential deposition process, thus achieving the feasible tunability of excitonic properties and lasing performance in hybrid metal-halide perovskites. The lasing threshold is at around 230 μJ cm(-2) in this solution-processed organic-inorganic lead-halide material, which is comparable to the colloidal quantum dot lasers. The efficient stimulated emission originates from the multiple random scattering provided by the micro-meter scale rugged morphology and polycrystalline grain boundaries. Thus the excitonic properties in perovskites exhibit high correlation with the formed morphology of the perovskite nanocrystals. Compared to the conventional lasers normally serving as a coherent light source, the perovskite random lasers are promising in making low-cost thin-film lasing devices for flexible and speckle-free imaging applications.

  12. Examination of the solution behaviors of the giant inorganic-organic amphiphilic hybrids

    Science.gov (United States)

    Zhang, Baofang

    Presently, the self-assembly behaviors of traditional small surfactants and amphiphilic block copolymers are fairly well understood. In comparison, rather little is known about the self-assembly behaviors of the giant inorganic-organic amphiphilic hybrids in solution. It remains a wide open field to explore. Giant inorganic-organic amphiphilic hybrids, consisting of nanoscale inorganic clusters and organic functional groups, represent a novel class of functional hybrid materials. They have unique physical and chemical properties and potential applications in catalysis, electronic, optics, magnetic materials, medicine and biology. Therefore, as emerging building blocks, they have promising prospects in the advanced materials. In this PhD work, several representative giant inorganic-organic amphiphilic hybrids (triangular-shaped polyoxometalate (POM)-containing inorganic/organic amphiphilic hybrids, POM-containing fluorosurfactants hybrids, POM-containing peptide hybrids POM-peptide hybrids and polyhedral oligometric silsesquioxane (POSS)-polystyrene (PS) are chosen for studying their self-assembly behaviors in solution. Based on the knowledge of the physical chemistry, colloid and polymer science, we focus on the mechanism of the self-assembly process, and the morphology control of the supramolecular structures through the internal and external conditions, such as the composition of the giant amphiphilies, molecular architectures, solvent nature, temperature, concentration, and extrally added salts. It is found that the counterion-meditated interactions dominate the self-assembly of triangular-shaped hybrids in acetone/water mixed solutions, due to the highly dominant hydrophilic portions; the solvent-swelling effect, instead of the charge effect, dominates the whole self-assembly process of the POM-containing fluorosurfactants; the analogy between small surfactants and giant amphiphiles POSS-PS allows a rough assessment of the possible morphologies of the

  13. Synthesis of magnetic nanoporous carbon from metal-organic framework for the fast removal of organic dye from aqueous solution

    Science.gov (United States)

    Jiao, Caina; Wang, Yanen; Li, Menghua; Wu, Qiuhua; Wang, Chun; Wang, Zhi

    2016-06-01

    In this paper, a magnetic nanoporous carbon (Fe3O4/NPC) was successfully synthesized by using MOF-5 as carbon precursor and Fe salt as magnetic precursor. The texture properties of the as-synthesized nanocomposite were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibration sample magnetometer (VSM), and N2 adsorption-desorption isotherms. The Fe3O4/NPC had a high surface area with strong magnetic strength. Its adsorption behavior was tested by its adsorption capacity for the removal of methylene blue from aqueous solution. The results demonstrated that the Fe3O4/NPC had a high adsorption capacity, rapid adsorption rate, and easy magnetic separabilty. Moreover, the adsorbent could be easily regenerated by washing it with ethanol. The Fe3O4/NPC can be used as a good alternative for the effective removal of organic dyes from wastewater.

  14. Hydrophobic Modification of Maltodextrin in Organic Phase%有机相中麦芽糊精疏水改性工艺的研究

    Institute of Scientific and Technical Information of China (English)

    罗建勇; 黄强; 扶雄; 张嘉诚; 刘莎

    2011-01-01

    以麦芽糊精为原料,对有机相中麦芽糊精疏水改性的最佳工艺进行研究.结果表明,当麦芽糊精的质量浓度为30%、溶剂为95%的乙醇、辛烯基琥珀酸酐的用量为糊精干基的6%时,加碱量对酯化反应的影响最大,各因素的重要性依次为:加碱量、反应温度、反应时间.高取代度辛烯基琥珀酸淀粉酯的最佳工艺条件为:反应温度33℃,反应时间3.0h,加碱量为糊精干基质量的1.20%.%The maltodextrin was modified by octenylsuccinic anhydrate (OSA) in organic phase. The optimum technical conditions were studied. The concentration of the maltodextrin was 30%; 95% ethanol was used as the organic phase; and the dosage ofthe OSA was 6%. The results showed that the concentration of sodium hydroxide had great effect on the esterification reaction. The order of the importance of the three factors was: sodium hydroxide addition, reaction temperature, reaction time. The optimum reaction temperature, reaction time, and sodium hydroxide addition were 33 ℃, 3.0 h and 1.20% ofmaltodextrin (dry base), respectively.

  15. Solution coating of large-area organic semiconductor thin films with aligned single-crystalline domains

    KAUST Repository

    Diao, Ying

    2013-06-02

    Solution coating of organic semiconductors offers great potential for achieving low-cost manufacturing of large-area and flexible electronics. However, the rapid coating speed needed for industrial-scale production poses challenges to the control of thin-film morphology. Here, we report an approach - termed fluid-enhanced crystal engineering (FLUENCE) - that allows for a high degree of morphological control of solution-printed thin films. We designed a micropillar-patterned printing blade to induce recirculation in the ink for enhancing crystal growth, and engineered the curvature of the ink meniscus to control crystal nucleation. Using FLUENCE, we demonstrate the fast coating and patterning of millimetre-wide, centimetre-long, highly aligned single-crystalline organic semiconductor thin films. In particular, we fabricated thin films of 6,13-bis(triisopropylsilylethynyl) pentacene having non-equilibrium single-crystalline domains and an unprecedented average and maximum mobilities of 8.1±1.2 cm2 V-1 s -1 and 11 cm2 V-1 s-1. FLUENCE of organic semiconductors with non-equilibrium single-crystalline domains may find use in the fabrication of high-performance, large-area printed electronics. © 2013 Macmillan Publishers Limited. All rights reserved.

  16. Solution-processible organic-inorganic hybrid bipolar field-effect transistors

    Science.gov (United States)

    Chae, Gil Jo; Kim, Kang Dae; Cho, Shinuk; Walker, Bright; Seo, Jung Hwa

    2016-04-01

    Organic-inorganic hybrid bipolar field-effect transistors (HBFETs) comprising a layer of p-type organic poly(3-hexylthiophene) (P3HT) separated from a parallel layer of n-type inorganic zinc oxide (ZnO) were demonstrated by solution processing. In order to achieve balanced hole and electron mobilities, we initially optimized the hole-transporting P3HT channel by the addition of the polar non-solvent acetonitrile (AN) to P3HT solutions in chloroform, which induced a selfassembled nano-fibril morphology and an enhancement of hole mobilities. For the electron channel, a wet-chemically-prepared ZnO layer was optimized by thermal annealing. Unipolar P3HT FET with 5% AN exhibited the highest hole mobility of 7.20 × 10-2 cm2V-1s-1 while the highest electron mobility (3.64 × 10-2 cm2V-1s-1) was observed in unipolar ZnO FETs annealed at 200°C. The organic-inorganic HBFETs consisting of the P3HT layer with 5% AN and ZnO annealed at 200°C exhibited well-balanced hole and electron mobilities of 1.94 × 10-2 cm2V-1s-1 and 1.98 × 10-2 cm2V-1s-1, respectively.

  17. Solution coating of large-area organic semiconductor thin films with aligned single-crystalline domains.

    Science.gov (United States)

    Diao, Ying; Tee, Benjamin C-K; Giri, Gaurav; Xu, Jie; Kim, Do Hwan; Becerril, Hector A; Stoltenberg, Randall M; Lee, Tae Hoon; Xue, Gi; Mannsfeld, Stefan C B; Bao, Zhenan

    2013-07-01

    Solution coating of organic semiconductors offers great potential for achieving low-cost manufacturing of large-area and flexible electronics. However, the rapid coating speed needed for industrial-scale production poses challenges to the control of thin-film morphology. Here, we report an approach--termed fluid-enhanced crystal engineering (FLUENCE)--that allows for a high degree of morphological control of solution-printed thin films. We designed a micropillar-patterned printing blade to induce recirculation in the ink for enhancing crystal growth, and engineered the curvature of the ink meniscus to control crystal nucleation. Using FLUENCE, we demonstrate the fast coating and patterning of millimetre-wide, centimetre-long, highly aligned single-crystalline organic semiconductor thin films. In particular, we fabricated thin films of 6,13-bis(triisopropylsilylethynyl) pentacene having non-equilibrium single-crystalline domains and an unprecedented average and maximum mobilities of 8.1±1.2 cm(2) V(-1) s(-1) and 11 cm(2) V(-1) s(-1). FLUENCE of organic semiconductors with non-equilibrium single-crystalline domains may find use in the fabrication of high-performance, large-area printed electronics.

  18. Adsorption on Mesoporous Metal-Organic Frameworks in Solution: Aromatic and Heterocyclic Compounds.

    Science.gov (United States)

    Samokhvalov, Alexander

    2015-11-16

    Adsorption and desorption play major roles in separations, purification of water, waste streams, liquid fuels, catalysis, biomedicine and chromatography. Mesoporous metal-organic frameworks (MOFs) with pore sizes 2-50 nm are particularly suitable for adsorption of organic compounds in solution. Tens of thousands of aromatic and heterocyclic compounds are major components of liquid fuels, feedstock for industrial synthesis, solvents, dyestuffs, agricultural chemicals, medicinal drugs, food additives, and so forth. This Review provides a systematization and analysis of studies on adsorption/desorption on mesoporous MOFs in solution and their underlying chemical mechanisms. The (in)stability of mesoporous MOFs in water is critically discussed. Adsorption capacity and selectivity are covered for organic dyes, medicinal drugs, major components of liquid fuels, and miscellaneous industrial chemicals. Ionic interactions, Brønsted acid-base interactions, hydrogen bonding, coordination bonding, π-π interactions, and non-specific interactions are covered amongst adsorption mechanisms. The effects of post-synthetic modifications of mesoporous MOFs on their stability, adsorption capacity, selectivity, and mechanisms of adsorption and desorption are analyzed. To encourage research in this quickly growing field, we identify "niches" for which no application-oriented and/or mechanistic studies were reported. Perspectives and limitations of a wide use of mesoporous MOFs as industrial sorbents are discussed.

  19. Solution coating of large-area organic semiconductor thin films with aligned single-crystalline domains

    Science.gov (United States)

    Diao, Ying; Tee, Benjamin C.-K.; Giri, Gaurav; Xu, Jie; Kim, Do Hwan; Becerril, Hector A.; Stoltenberg, Randall M.; Lee, Tae Hoon; Xue, Gi; Mannsfeld, Stefan C. B.; Bao, Zhenan

    2013-07-01

    Solution coating of organic semiconductors offers great potential for achieving low-cost manufacturing of large-area and flexible electronics. However, the rapid coating speed needed for industrial-scale production poses challenges to the control of thin-film morphology. Here, we report an approach—termed fluid-enhanced crystal engineering (FLUENCE)—that allows for a high degree of morphological control of solution-printed thin films. We designed a micropillar-patterned printing blade to induce recirculation in the ink for enhancing crystal growth, and engineered the curvature of the ink meniscus to control crystal nucleation. Using FLUENCE, we demonstrate the fast coating and patterning of millimetre-wide, centimetre-long, highly aligned single-crystalline organic semiconductor thin films. In particular, we fabricated thin films of 6,13-bis(triisopropylsilylethynyl) pentacene having non-equilibrium single-crystalline domains and an unprecedented average and maximum mobilities of 8.1±1.2 cm2 V-1 s-1 and 11 cm2 V-1 s-1. FLUENCE of organic semiconductors with non-equilibrium single-crystalline domains may find use in the fabrication of high-performance, large-area printed electronics.

  20. Organics produced by irradiation of frozen and liquid HCN solutions: implications for chemical evolution studies.

    Science.gov (United States)

    Colín-García, M; Negrón-Mendoza, A; Ramos-Bernal, S

    2009-04-01

    Hydrogen cyanide (HCN), an important precursor of organic compounds, is widely present in extraterrestrial environments. HCN is also readily synthesized in prebiotic simulation experiments. To gain insight into the radiation chemistry of one of the most important and highly versatile constituents of cometary ices, we examined the behavior of over-irradiated frozen and liquid HCN solutions under ionizing radiation. The samples were exposed to gamma radiation at a dose range from 0 up to 419 kGy. Ultraviolet spectroscopy and gas chromatography were used to follow the process. The analyses confirmed that gamma-ray irradiation of liquid HCN solutions generates several organic products. Many of them are essential to life; we verified the presence of carboxylic acids (some of them members of the Krebs cycle) as well as free amino acids and urea. These are the first studies to reveal the presence of these compounds in experiments performed at low temperatures and bulk irradiation. Organic material was produced even at low temperatures and low radiation doses. This work strongly supports the presumption that, as a parent molecule, HCN played a central essential role in the process of chemical evolution on early Earth, comets, and other extraterrestrial environments.

  1. Hammerhead ribozyme activity and oligonucleotide duplex stability in mixed solutions of water and organic compounds

    Directory of Open Access Journals (Sweden)

    Shu-ichi Nakano

    2014-01-01

    Full Text Available Nucleic acids are useful for biomedical targeting and sensing applications in which the molecular environment is different from that of a dilute aqueous solution. In this study, the influence of various types of mixed solutions of water and water-soluble organic compounds on RNA was investigated by measuring the catalytic activity of the hammerhead ribozyme and the thermodynamic stability of an oligonucleotide duplex. The compounds with a net neutral charge, such as poly(ethylene glycol, small primary alcohols, amide compounds, and aprotic solvent molecules, added at high concentrations changed the ribozyme-catalyzed RNA cleavage rate, with the magnitude of the effect dependent on the NaCl concentration. These compounds also changed the thermodynamic stability of RNA base pairs of an oligonucleotide duplex and its dependence on the NaCl concentration. Specific interactions with RNA molecules and reduced water activity could account for the inhibiting effects on the ribozyme catalysis and destabilizing effects on the duplex stability. The salt concentration dependence data correlated with the dielectric constant, but not with water activity, viscosity, and the size of organic compounds. This observation suggests the significance of the dielectric constant effects on the RNA reactions under molecular crowding conditions created by organic compounds.

  2. Organics Produced by Irradiation of Frozen and Liquid HCN Solutions: Implications for Chemical Evolution Studies

    Science.gov (United States)

    Colín-García, M.; Negrón-Mendoza, A.; Ramos-Bernal, S.

    2009-04-01

    Hydrogen cyanide (HCN), an important precursor of organic compounds, is widely present in extraterrestrial environments. HCN is also readily synthesized in prebiotic simulation experiments. To gain insight into the radiation chemistry of one of the most important and highly versatile constituents of cometary ices, we examined the behavior of over-irradiated frozen and liquid HCN solutions under ionizing radiation. The samples were exposed to gamma radiation at a dose range from 0 up to 419 kGy. Ultraviolet spectroscopy and gas chromatography were used to follow the process. The analyses confirmed that gamma-ray irradiation of liquid HCN solutions generates several organic products. Many of them are essential to life; we verified the presence of carboxylic acids (some of them members of the Krebs cycle) as well as free amino acids and urea. These are the first studies to reveal the presence of these compounds in experiments performed at low temperatures and bulk irradiation. Organic material was produced even at low temperatures and low radiation doses. This work strongly supports the presumption that, as a parent molecule, HCN played a central essential role in the process of chemical evolution on early Earth, comets, and other extraterrestrial environments.

  3. Formulating essential oil microemulsions as washing solutions for organic fresh produce production.

    Science.gov (United States)

    Zhang, Linhan; Critzer, Faith; Davidson, P Michael; Zhong, Qixin

    2014-12-15

    Applications of plant-derived organic essential oils (EOs) as antimicrobials for post-harvest produce operations are limited by their low water solubility. To dissolve EOs in water, microemulsions were studied using two surfactants permitted for organic production, sucrose octanoate ester (SOE) and soy lecithin that were mixed at various mass ratios before dilution with water to 40% w/w. EOs were then mixed with the surfactant solution by hand shaking. Based on visual transparency, intermediate lecithin:SOE mass ratios favoured the formation of microemulsions, e.g., up to 4.0% clove bud oil at ratios of 2:8 and 3:7, and 4.0% cinnamon bark oil and 3.0% thyme oil at ratios of 2:8 and 1:9, respectively. Microemulsions with intermediate lecithin:SOE mass ratios had a relatively low viscosity and better ability to wet fresh produce surfaces. The microemulsions established in this work may be used as washing solutions to enhance the microbial safety of organic fresh produce.

  4. Degradation/oxidation susceptibility of organic photovoltaic cells in aqueous solutions

    Science.gov (United States)

    Habib, K.; Husain, A.; Al-Hazza, A.

    2015-12-01

    A criterion of the degradation/oxidation susceptibility of organic photovoltaic (OPV) cells in aqueous solutions was proposed for the first time. The criterion was derived based on calculating the limit of the ratio value of the polarization resistance of an OPV cell in aqueous solution (Rps) to the polarization resistance of the OPV cell in air (Rpair). In other words, the criterion lim(Rps/Rpair) = 1 was applied to determine the degradation/oxidation of the OPV cell in the aqueous solution when Rpair became equal (increased) to Rps as a function of time of the exposure of the OPV cell to the aqueous solution. This criterion was not only used to determine the degradation/oxidation of different OPV cells in a simulated operational environment but also it was used to determine the electrochemical behavior of OPV cells in deionized water and a polluted water with fine particles of sand. The values of Rps were determined by the electrochemical impedance spectroscopy at low frequency. In addition, the criterion can be applied under diverse test conditions with a predetermined period of OPV operations.

  5. Degradation/oxidation susceptibility of organic photovoltaic cells in aqueous solutions.

    Science.gov (United States)

    Habib, K; Husain, A; Al-Hazza, A

    2015-12-01

    A criterion of the degradation/oxidation susceptibility of organic photovoltaic (OPV) cells in aqueous solutions was proposed for the first time. The criterion was derived based on calculating the limit of the ratio value of the polarization resistance of an OPV cell in aqueous solution (Rp(s)) to the polarization resistance of the OPV cell in air (Rp(air)). In other words, the criterion lim(Rp(s)/Rp(air)) = 1 was applied to determine the degradation/oxidation of the OPV cell in the aqueous solution when Rp(air) became equal (increased) to Rp(s) as a function of time of the exposure of the OPV cell to the aqueous solution. This criterion was not only used to determine the degradation/oxidation of different OPV cells in a simulated operational environment but also it was used to determine the electrochemical behavior of OPV cells in deionized water and a polluted water with fine particles of sand. The values of Rp(s) were determined by the electrochemical impedance spectroscopy at low frequency. In addition, the criterion can be applied under diverse test conditions with a predetermined period of OPV operations.

  6. Solution growth of metal-organic complex CuTCNQ in small dimension interconnect structures

    Science.gov (United States)

    Demolliens, A.; Muller, Ch.; Müller, R.; Turquat, Ch.; Goux, L.; Deleruyelle, D.; Wouters, D. J.

    2010-11-01

    In this paper, we report two different elaboration routes to grow metal-organic complex CuTCNQ in liquid phase within small interconnect structures (i.e. via holes opened in SiO 2/SiC stack). The basic common idea relies on the formation of CuTCNQ material from the partial corrosion of a Cu bottom electrode by a TCNQ-based solution. The two solution growth methods are compared in terms of (i) via holes filling; (ii) local microstructure of CuTCNQ complex and (iii) quality of interface between CuTCNQ and copper metallic electrode. In the first route, in the reaction of the substrate with a TCNQ/copper salt solution in acetonitrile/toluene, a rapid formation of porous CuTCNQ complex is observed with an over-growth outside interconnect structures and many voids within via holes and at the interface with Cu layer. In contrast to this "mushroom-like" growth, the reaction of the substrate with a TCNQ solution in acetonitrile/2-butanone results in a "crystal-like" dense CuTCNQ complex within via holes and a CuTCNQ/Cu interface free of voids. In the latter case, satisfactory electrical performances are expected for future resistive switching memory devices.

  7. 土壤和沉积物中疏水性有机污染物的锁定及其环境效应%SEQUESTRATION OF HYDROPHOBIC ORGANIC CONTAMINANTS IN SOIL/SEDIMENT AND ITS ENVIRONMENTAL IMPACT

    Institute of Scientific and Technical Information of China (English)

    段林; 张承东; 陈威

    2011-01-01

    Numerous studies have shown that desorption of hydrophobic organic contaminants from soil/sediment is biphasic: only a fraction of contaminants in soil/sediment can readily desorb, whereas desorption of the remaining fraction is very difficult and contaminants persist much longer than what is predicted using the conventional desorption models. This phenomenon is typically referred to as "resistant desorption ","irreversible sorption", or "sequestration". While sequestration can significantly affect the effectiveness of soil and sediment remediation processes, it can also lessen the risk of contaminated soil/sediment due to reduced bioavailability of sequestrated pollutants. This paper reviews the mechanisms controlling sequestration,and introduces a more accurate model that can be used to predict the desorption of hydrophobic organic contaminants from soil/sediment. The impact of sequestration on the fate and bioavailability of pollutants, and on the management of contaminated sites is discussed.%大量研究表明,吸附到土壤和沉积物中的疏水性有机物只有部分能够较容易地解吸出来,而残留的部分很难解吸.这种现象常被称为"解吸滞后","不可逆吸附",或者"锁定".锁定会导致受污染土壤和沉积物修复效率的降低;但与此同时,锁定也会降低受污染土壤和沉积物的环境风险.本文综述了土壤和沉积物中疏水性有机污染物锁定的典型热力学和动力学特征、以及锁定的形成机理,介绍了一个能够以简单参数准确量化污染物从土壤和沉积物中解吸行为的数学模型,并探讨了锁定对疏水性有机污染物迁移归宿、生物可利用性、以及污染场地生态风险的影响.

  8. Molecular floating-gate organic nonvolatile memory with a fully solution processed core architecture

    Science.gov (United States)

    Wu, Chao; Wang, Wei; Song, Junfeng

    2016-11-01

    In this paper, we demonstrated a floating-gate organic thin film transistor based nonvolatile memory, in which the core architecture was processed by a sequential three-step solution spin-coating method. The molecular semiconductor 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-Pen) distributing in the matrix of polymer poly(styrene) (PS), acting as the floating-gate and tunneling layer, respectively, was processed by one-step spin-coating from their blending solution. The effect of the proportion of TIPS-Pen in the matrix of PS on the memory performances of devices was researched. As a result, a good nonvolatile memory was achieved, with a memory window larger than 25 V, stable memory endurance property over 500 cycles and retention time longer than 5000 s with a high memory ratio larger than 102, at an optimal proportion of TIPS-Pen in the matrix of PS.

  9. Analyses of organics in irradiated aqueous N,N-diethylhydroxylamine solution

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The organics in γ-ray irradiated aqueous N, N-diethylhydroxylamine (DEHA) solution, which is used as a reducing agent in reprocessing spent nuclear fuel, were analyzed with gas chromatography equipped with FFAP capil-lary column and flame-ionization detector. It was found that irradiated DEHA solutions contained acetaldehyde, ethanol, and acetic acid. For DEHA of 0.2 mol/L irradiated to 10~1000 kGy, the concents of acetaldehyde, ethanol and acetic acid are (9.7~18.7)×10-3, (0.4~23.4)×10-3 and (6.5~11.7)×10-3 mol/L, respectively. The concentration of DEHA decreases obviously with the dose.

  10. Flexible, Luminescent Metal-Organic Frameworks Showing Synergistic Solid-Solution Effects on Porosity and Sensitivity.

    Science.gov (United States)

    Liu, Si-Yang; Zhou, Dong-Dong; He, Chun-Ting; Liao, Pei-Qin; Cheng, Xiao-Ning; Xu, Yan-Tong; Ye, Jia-Wen; Zhang, Jie-Peng; Chen, Xiao-Ming

    2016-12-23

    Mixing molecular building blocks in the solid solution manner is a valuable strategy to obtain structures and properties in between the isostructural parent metal-organic frameworks (MOFs). We report nonlinear/synergistic solid-solution effects using highly related yet non-isostructural, phosphorescent Cu(I) triazolate frameworks as parent phases. Near the phase boundaries associated with conformational diversity and ligand heterogeneity, the porosity (+150 %) and optical O2 sensitivity (410 times, limit of detection 0.07 ppm) can be drastically improved from the best-performing parent MOFs and even exceeds the records hold by precious-metal complexes (3 ppm) and C70 (0.2 ppm).

  11. Tunable catalytic activity of solid solution metal-organic frameworks in one-pot multicomponent reactions.

    Science.gov (United States)

    Aguirre-Díaz, Lina María; Gándara, Felipe; Iglesias, Marta; Snejko, Natalia; Gutiérrez-Puebla, Enrique; Monge, M Ángeles

    2015-05-20

    The aim of this research is to establish how metal-organic frameworks (MOFs) composed of more than one metal in equivalent crystallographic sites (solid solution MOFs) exhibit catalytic activity, which is tunable by virtue of the metal ions ratio. New MOFs with general formula [InxGa1-x(O2C2H4)0.5(hfipbb)] were prepared by the combination of Ga and In. They are isostructural with their monometal counterparts, synthesized with Al, Ga, and In. Differences in their behavior as heterogeneous catalysts in the three-component, one pot Strecker reaction illustrate the potential of solid solution MOFs to provide the ability to address the various stages involved in the reaction mechanism.

  12. Beaded nanofibers assembled from double-hydrophobic elastin-like block polypeptides: Effects of trifluoroethanol.

    Science.gov (United States)

    Le, Duc H T; Okubo, Tatsuya; Sugawara-Narutaki, Ayae

    2015-03-01

    A "double-hydrophobic" elastin-like triblock polypeptide GPG has been constructed by mimicking the localization of proline- and glycine-rich hydrophobic domains of native elastin, a protein that provides elasticity and resilience to connective tissues. In this study, the effects of trifluoroethanol (TFE), an organic solvent that strongly affects secondary structures of polypeptides on self-assembly of GPG in aqueous solutions were systematically studied. Beaded nanofiber formation of GPG, where nanoparticles are initially formed by coacervation of the polypeptides followed by their connection into one-dimensional nanostructures, is accelerated by the addition of TFE at the concentrations up to 30% (v/v), whereas aggregates of nanoparticles are formed at 60% TFE. The concentration-dependent assembly pattern discussed is based on the influence of TFE on the secondary structures of GPG. Well-defined nanofibers whose diameter and secondary structures are controlled by TFE concentration may be ideal building blocks for constructing bioelastic materials in tissue engineering.

  13. The effect of heterogeneity and surface roughness on soil hydrophobicity

    Science.gov (United States)

    Hallin, I.; Bryant, R.; Doerr, S. H.; Douglas, P.

    2010-05-01

    Soil water repellency, or hydrophobicity, can develop under both natural and anthropogenic conditions. Forest fires, vegetation decomposition, microbial activity and oil spills can all promote hydrophobic behaviour in surrounding soils. Hydrophobicity can stabilize soil organic matter pools and decrease evapotranspiration, but there are many negative impacts of hydrophobicity as well: increased erosion of topsoil, an increasingly scarce resource; increased runoff, which can lead to flooding; and decreased infiltration, which directly affects plant health. The degree of hydrophobicity expressed by soil can vary greatly within a small area, depending partly on the type and severity of the disturbance as well as on temporal factors such as water content and microbial activity. To date, many laboratory investigations into soil hydrophobicity have focused on smooth particle surfaces. As a result, our understanding of how hydrophobicity develops on rough surfaces of macro, micro and nano-particulates is limited; we are unable to predict with certainty how these soil particles will behave on contact with water. Surface chemistry is the main consideration when predicting hydrophobic behaviour of smooth solids, but for particles with rough surfaces, hydrophobicity is believed to develop as a combination of surface chemistry and topography. Topography may reflect both the arrangement (aggregation) of soil particles and the distribution of materials adsorbed on particulate surfaces. Patch-wise or complete coverage of rough soil particles by hydrophobic material may result in solid/water contact angles ≥150° , at which point the soil may be classified as super-hydrophobic. Here we present a critical review of the research to date on the effects of heterogeneity and surface roughness on soil hydrophobicity in which we discuss recent advances, current trends, and future research areas. References: Callies, M., Y. Chen, F. Marty, A. Pépin and D. Quéré. 2005. Microfabricated

  14. Effect of water content on the water repellency for hydrophobized sands

    Science.gov (United States)

    Subedi, S.; Kawamoto, K.; Kuroda, T.; Moldrup, P.; Komatsu, T.

    2011-12-01

    Alternative earthen covers such as capillary barriers (CBs) and evapotranspirative covers are recognized as useful technical and low-cost solutions for limiting water infiltration and controlling seepage flow at solid waste landfills in semi-arid and arid regions. However, their application to the landfills at wet regions seems to be matter of concern due to loss of their impending capability under high precipitation. One of the possible techniques to enhance the impermeable properties of CBs is to alter soil grain surfaces to be water-repellent by mixing/coating hydrophobic agents (HAs). In order to examine a potential use of model sands hydrophobized with locally available and environmental-friendly HAs such as oleic acid (OA) and stearic acid (SA) for hydrophobic CBs. In the present study, we first characterized the effect of water content on the degree of water repellency (WR) for hydrophobized sands and volcanic ash soil at different depth. Secondly, the time dependency of the contact angle in hydrophobized sands and volcanic ash soils at different water content was evaluated. Further, the effects of hydrophobic organic matter contents on the WR of hydrophobized sands were investigated by horizontal infiltration test. We investigated the degree of WR as functions of volumetric water content (θ) of a volcanic ash soil samples from different depth and water adjusted hydrophobized sand samples with different ratio of HAs by using sessile drop method (SDM). The initial contact angle (αi) measured from SDM decreased gradually with increasing water content in OA and SA coated samples. Measured αi values for volcanic ash soils increased with increasing water content and reached a peak values of 111.7o at θ= 0.325 cm3 cm-3, where-after αi gradually decreased. Each test sample exhibited sharp decrease in contact angle with time at higher water content. Sorptivity values for oleic acid coated samples decreased with increasing HA content and reached the minimum

  15. Hydrogels with micellar hydrophobic (nanodomains

    Directory of Open Access Journals (Sweden)

    Miloslav ePekař

    2015-01-01

    Full Text Available Hydrogels containing hydrophobic domains or nanodomains, especially of the micellar type, are reviewed. Examples of the reasons for introducing hydrophobic domains into hydrophilic gels are given; typology of these materials is introduced. Synthesis routes are exemplified and properties of a variety of such hydrogels in relation with their intended applications are described. Future research needs are identified briefly.

  16. Electro-spun organic nanofibers elaboration process investigations using comparative analytical solutions.

    Science.gov (United States)

    Colantoni, A; Boubaker, K

    2014-01-30

    In this paper Enhanced Variational Iteration Method, EVIM is proposed, along with the BPES, for solving Bratu equation which appears in the particular elecotrospun nanofibers fabrication process framework. Elecotrospun organic nanofibers, with diameters less than 1/4 microns have been used in non-wovens and filtration industries for a broad range of filtration applications in the last decade. Electro-spinning process has been associated to Bratu equation through thermo-electro-hydrodynamics balance equations. Analytical solutions have been proposed, discussed and compared.

  17. All solution processed organic thin film transistor-backplane with printing technology for electrophoretic display

    Science.gov (United States)

    Lee, Myung W.; Song, C.K.

    2012-01-01

    In this study, solution processes were developed for backplane using an organic thin film transistor (OTFT) as a driving device for an electrophoretic display (EPD) panel. The processes covered not only the key device of OTFTs but also interlayer and pixel electrodes. The various materials and printing processes were adopted to achieve the requirements of devices and functioning layers. The performance of OTFT of the backplane was sufficient to drive EPD sheet by producing a mobility of 0.12 cm2/v x sec and on/off current ratio of 10(5).

  18. Some organic compounds as inhibitors for the corrosion of aluminum alloy 6063 in deaerated carbonate solution

    Energy Technology Data Exchange (ETDEWEB)

    Bazzi, L.; Hamdani, M. [Lab. de Chimie Physique, Agadir (Morocco); Kertit, S. [Ecole Normale Superieure de Takaddoum, Rabat (Morocco). Lab. de Physico-Chimie des Materiaux

    1995-11-01

    Some organic compounds were tested as corrosion inhibitors for aluminum alloy 6063 (Al 6063, UNS A96063) in a deaerated carbonate solution using the electrochemical polarization method. The compounds studied were thiourea (TOR), diorthoaminodiphenyldisulfane (DOAPD), and benzotriazole (BTA). Results showed DOAPD was the best inhibitor. Its inhibition efficiency reaches a maximum value of 95.8% at 10{sup {minus}2} M. Polarization measurements indicated DOAPD acted as a cathodic and anodic (mixed) inhibitor without changing the mechanism of the water evolution reaction. DOAPD was adsorbed on the aluminum surface according to a Langmuir isotherm model. The other compounds tested had no effect on pitting corrosion of Al 6063.

  19. Metal–Organic Frameworks Stabilize Solution-Inaccessible Cobalt Catalysts for Highly Efficient Broad-Scope Organic Transformations

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Teng; Manna, Kuntal; Lin, Wenbin (UC)

    2016-05-06

    New and active earth-abundant metal catalysts are critically needed to replace precious metal-based catalysts for sustainable production of commodity and fine chemicals. We report here the design of highly robust, active, and reusable cobalt-bipyridine- and cobalt-phenanthroline-based metal–organic framework (MOF) catalysts for alkene hydrogenation and hydroboration, aldehyde/ketone hydroboration, and arene C–H borylation. In alkene hydrogenation, the MOF catalysts tolerated a variety of functional groups and displayed unprecedentedly high turnover numbers of ~2.5 × 106 and turnover frequencies of ~1.1 × 105 h–1. Structural, computational, and spectroscopic studies show that site isolation of the highly reactive (bpy)Co(THF)2 species in the MOFs prevents intermolecular deactivation and stabilizes solution-inaccessible catalysts for broad-scope organic transformations. Computational, spectroscopic, and kinetic evidence further support a hitherto unknown (bpy•–)CoI(THF)2 ground state that coordinates to alkene and dihydrogen and then undergoing σ-complex-assisted metathesis to form (bpy)Co(alkyl)(H). Reductive elimination of alkane followed by alkene binding completes the catalytic cycle. MOFs thus provide a novel platform for discovering new base-metal molecular catalysts and exhibit enormous potential in sustainable chemical catalysis.

  20. Limiting the intensity of femtosecond pulses with anti-stokes excitation of organic dye solutions

    Science.gov (United States)

    Svetlichnyi, V. A.; Meshalkin, Yu. P.; Kirpichnikov, A. V.; Pestryakov, E. V.

    2010-08-01

    Results of experimental investigations into the nonlinear absorption of the symmetric polymethine 1-butyl -3,3-dimethyl-2-[5-(1-butyl-3,3-dimethyl-3H-benz[e]indoline-2-uledene)-1,3-pentadienyl]-3H-benz[e]indolium perchlorate dye solution excited by radiation of a femtosecond titanium-sapphire laser (20 fs, 800 nm, 75 MHz, and 300 mW) by the open aperture z-scan method are presented. Record limitation of the femtosecond laser radiation intensity (by 300 times at a 93% linear transmission of the medium) was achieved. The nonlinear absorption mechanisms in organic dyes with anti-Stokes excitation by wideband high-power pulsed radiation to the absorption band edge and the prospects for organic dye application for limitation of the femtosecond laser radiation intensity are discussed.

  1. Aqueous metal–organic solutions for YSZ thin film inkjet deposition

    DEFF Research Database (Denmark)

    Gadea, Christophe; Hanniet, Q.; Lesch, A.

    2017-01-01

    Inkjet printing of 8% Y2O3-stabilized ZrO2 (YSZ) thin films is achieved by designing a novel water-based reactive ink for Drop-on-Demand (DoD) inkjet printing. The ink formulation is based on a novel chemical strategy that consists of a combination of metal oxide precursors (zirconium alkoxide...... and yttrium salt), water and a nucleophilic agent, i.e. n-methyldiethanolamine (MDEA). This chemistry leads to metal–organic complexes with long term ink stability and high precision printability. Ink rheology and chemical reactivity are analyzed and controlled in terms of metal–organic interactions...... in the solutions. Thin dense nanocrystalline YSZ films below 150 nm are obtained by low temperature calcination treatments (400–500 °C), making the deposition suitable for a large variety of substrates, including silicon, glass and metals. Thin films and printed patterns achieve full densification with no lateral...

  2. Trace organic solutes in closed-loop forward osmosis applications: influence of membrane fouling and modeling of solute build-up.

    Science.gov (United States)

    D'Haese, Arnout; Le-Clech, Pierre; Van Nevel, Sam; Verbeken, Kim; Cornelissen, Emile R; Khan, Stuart J; Verliefde, Arne R D

    2013-09-15

    In this study, trace organics transport in closed-loop forward osmosis (FO) systems was assessed. The FO systems considered, consisted of an FO unit and a nanofiltration (NF) or reverse osmosis (RO) unit, with the draw solution circulating between both units. The rejection of trace organics by FO, NF and RO was tested. It was found that the rejection rates of FO were generally comparable with NF and lower than RO rejection rates. To assess the influence of fouling in FO on trace organics rejection, FO membranes were fouled with sodium alginate, bovine serum albumin or by biofilm growth, after which trace organics rejection was tested. A negative influence of fouling on FO rejection was found which was limited in most cases, while it was significant for some compounds such as paracetamol and naproxen, indicating specific compound-foulant interactions. The transport mechanism of trace organics in FO was tested, in order to differentiate between diffusive and convective transport. The concentration of trace organics in the final product water and the build-up of trace organics in the draw solution were modeled assuming the draw solution was reconcentrated by NF/RO and taking into account different transport mechanisms for the FO membrane and different rejection rates by NF/RO. Modeling results showed that if the FO rejection rate is lower than the RO rejection rate (as is the case for most compounds tested), the added value of the FO-RO cycle compared to RO only at steady-state was small for diffusively and negative for convectively transported trace organics. Modeling also showed that trace organics accumulate in the draw solution.

  3. Asymptotic Solution of a Model for Bilayer Organic Diodes and Solar Cells

    KAUST Repository

    Richardson, Giles

    2012-11-15

    Organic diodes and solar cells are constructed by placing together two organic semiconducting materials with dissimilar electron affinities and ionization potentials. The electrical behavior of such devices has been successfully modeled numerically using conventional drift diffusion together with recombination (which is usually assumed to be bimolecular) and thermal generation. Here a particular model is considered and the dark current-voltage curve and the spatial structure of the solution across the device is extracted analytically using asymptotic methods. We concentrate on the case of Shockley-Read-Hall recombination but note the extension to other recombination mechanisms. We find that there are three regimes of behavior, dependent on the total current. For small currents-i.e., at reverse bias or moderate forward bias-the structure of the solution is independent of the total current. For large currents-i.e., at strong forward bias-the current varies linearly with the voltage and is primarily controlled by drift of charges in the organic layers. There is then a narrow range of currents where the behavior undergoes a transition between the two regimes. The magnitude of the parameter that quantifies the interfacial recombination rate is critical in determining where the transition occurs. The extension of the theory to organic solar cells generating current under illumination is discussed as is the analogous current-voltage curves derived where the photo current is small. Finally, by comparing the analytic results to real experimental data, we show how the model parameters can be extracted from the shape of current-voltage curves measured in the dark. © 2012 Society for Industrial and Applied Mathematics.

  4. A controlled auction market is a practical solution to the shortage of transplantable organs.

    Science.gov (United States)

    Kevorkian, J

    1992-01-01

    All attempts relying on pure altruism to meet the demand for transplantable donor organs have failed and continue to fail. The incentive of commercialization of an organ market would seem to be the only practical solution at this time. It is almost impossible to set fixed prices for such priceless items as human organs. The only fair, honest, and feasible approach is the establishment of a free and voluntary national or international auction system under the strict supervision and control of an exclusive, specially created administrative entity free of governmental or other partisan interference. The resultant flow of funds could be enormous and would enhance the welfare of all strata of society. Wealthy buyers would be removed from current waiting lists; the donor pool greatly expanded to perhaps surplus; the resultant money used to relieve the financial burdens on families involved, hospitals, insurance companies--and also used to buy organs for the indigent on waiting lists, pay for surgeries and hospitalization, and thereby increase the income and surgical experience of more surgeons. This proposed new system should include all live as well as brain-dead donors, cadavers and consenting individuals facing purposeful and pointless destruction by judicial execution.

  5. Changing water affinity from hydrophobic to hydrophilic in hydrophobic channels.

    Science.gov (United States)

    Ohba, Tomonori; Yamamoto, Shotaro; Kodaira, Tetsuya; Hata, Kenji

    2015-01-27

    The behavior of water at hydrophobic interfaces can play a significant role in determining chemical reaction outcomes and physical properties. Carbon nanotubes and aluminophosphate materials have one-dimensional hydrophobic channels, which are entirely surrounded by hydrophobic interfaces. Unique water behavior was observed in such hydrophobic channels. In this article, changes in the water affinity in one-dimensional hydrophobic channels were assessed using water vapor adsorption isotherms at 303 K and grand canonical Monte Carlo simulations. Hydrophobic behavior of water adsorbed in channels wider than 3 nm was observed for both adsorption and desorption processes, owing to the hydrophobic environment. However, water showed hydrophilic properties in both adsorption and desorption processes in channels narrower than 1 nm. In intermediate-sized channels, the hydrophobic properties of water during the adsorption process were seen to transition to hydrophilic behavior during the desorption process. Hydrophilic properties in the narrow channels for both adsorption and desorption processes are a result of the relatively strong water-channel interactions (10-15 kJ mol(-1)). In the 2-3 nm channels, the water-channel interaction energy of 4-5 kJ mol(-1) was comparable to the thermal translational energy. The cohesive water interaction was approximately 35 kJ mol(-1), which was larger than the others. Thus, the water affinity change in the 2-3 nm channels for the adsorption and desorption processes was attributed to weak water-channel interactions and strong cohesive interactions. These results are inherently important to control the properties of water in hydrophobic environments.

  6. Solution-Processed Ambipolar Organic Thin-Film Transistors by Blending p- and n-Type Semiconductors: Solid Solution versus Microphase Separation.

    Science.gov (United States)

    Xu, Xiaomin; Xiao, Ting; Gu, Xiao; Yang, Xuejin; Kershaw, Stephen V; Zhao, Ni; Xu, Jianbin; Miao, Qian

    2015-12-30

    Here, we report solid solution of p- and n-type organic semiconductors as a new type of p-n blend for solution-processed ambipolar organic thin film transistors (OTFTs). This study compares the solid-solution films of silylethynylated tetraazapentacene 1 (acceptor) and silylethynylated pentacene 2 (donor) with the microphase-separated films of 1 and 3, a heptagon-embedded analogue of 2. It is found that the solid solutions of (1)x(2)1-x function as ambipolar semiconductors, whose hole and electron mobilities are tunable by varying the ratio of 1 and 2 in the solid solution. The OTFTs of (1)0.5(2)0.5 exhibit relatively balanced hole and electron mobilities comparable to the highest values as reported for ambipolar OTFTs of stoichiometric donor-acceptor cocrystals and microphase-separated p-n bulk heterojunctions. The solid solution of (1)0.5(2)0.5 and the microphase-separated blend of 1:3 (0.5:0.5) in OTFTs exhibit different responses to light in terms of absorption and photoeffect of OTFTs because the donor and acceptor are mixed at molecular level with π-π stacking in the solid solution.

  7. Impact of Hydrophobic Pollutants' Behavior on Occupational and Environmental Health

    Directory of Open Access Journals (Sweden)

    Ijeoma Kanu

    2005-01-01

    Full Text Available This paper reviews the influence of hydrophobic pollutant behavior on environmental hazards and risks. The definition and examples of hydrophobic pollutants are given as a guide to better understand the sources of release and the media of dispersion in the environment. The properties and behavior of hydrophobic pollutants are described and their influence on environmental hazard and risk is reviewed and evaluated. The overall outcome of the assessment and evaluation showed that all hydrophobic pollutants are hazardous and risky to all organisms, including man. Their risk effects are due to their inherent persistence, bioaccumulation potential, environmental mobility, and reactivity. Their hazardous effects on organisms occur at varying spatial and temporal degrees of emissions, toxicities, exposures, and concentrations.

  8. Organic solutes in coconut palm seedlings under water and salt stresses

    Directory of Open Access Journals (Sweden)

    Alexandre R. A. da Silva

    Full Text Available ABSTRACT The objective of this study was to investigate the biochemical mechanisms associated with isolated and/or concurrent actions of drought and soil salinity in seedlings of coconut tree, through the accumulation of organic solutes (soluble carbohydrates, soluble amino N and free proline in leaves and roots. The experiment, conducted in a protected environment, in Fortaleza, Brazil, in a randomized block design, in a split-plot arrangement, evaluated the effects of different levels of water stress (plots by imposing distinct percentages of replacement of water losses through crop potential evapotranspiration - ETpc (20, 40, 60, 80 and 100%, associated with subplots consisting of increasing levels of soil salinity in saturation extract (1.72, 6.25, 25.80 and 40.70 dS m-1 provided by the soils collected in the Irrigated Perimeter of Morada Nova. Salinity did not change the concentration of organic solutes; however, there were increases in leaf and root levels of free proline in response to water stress, which contributes to the osmoregulation and/or osmoprotection of the species under adverse conditions of water supply.

  9. Ambipolar Small-Molecule:Polymer Blend Semiconductors for Solution-Processable Organic Field-Effect Transistors.

    Science.gov (United States)

    Kang, Minji; Hwang, Hansu; Park, Won-Tae; Khim, Dongyoon; Yeo, Jun-Seok; Kim, Yunseul; Kim, Yeon-Ju; Noh, Yong-Young; Kim, Dong-Yu

    2017-01-25

    We report on the fabrication of an organic thin-film semiconductor formed using a blend solution of soluble ambipolar small molecules and an insulating polymer binder that exhibits vertical phase separation and uniform film formation. The semiconductor thin films are produced in a single step from a mixture containing a small molecular semiconductor, namely, quinoidal biselenophene (QBS), and a binder polymer, namely, poly(2-vinylnaphthalene) (PVN). Organic field-effect transistors (OFETs) based on QBS/PVN blend semiconductor are then assembled using top-gate/bottom-contact device configuration, which achieve almost four times higher mobility than the neat QBS semiconductor. Depth profile via secondary ion mass spectrometry and atomic force microscopy images indicate that the QBS domains in the films made from the blend are evenly distributed with a smooth morphology at the bottom of the PVN layer. Bias stress test and variable-temperature measurements on QBS-based OFETs reveal that the QBS/PVN blend semiconductor remarkably reduces the number of trap sites at the gate dielectric/semiconductor interface and the activation energy in the transistor channel. This work provides a one-step solution processing technique, which makes use of soluble ambipolar small molecules to form a thin-film semiconductor for application in high-performance OFETs.

  10. Towards solution and refinement of organic crystal structures by fitting to the atomic pair distribution function.

    Science.gov (United States)

    Prill, Dragica; Juhás, Pavol; Billinge, Simon J L; Schmidt, Martin U

    2016-01-01

    A method towards the solution and refinement of organic crystal structures by fitting to the atomic pair distribution function (PDF) is developed. Approximate lattice parameters and molecular geometry must be given as input. The molecule is generally treated as a rigid body. The positions and orientations of the molecules inside the unit cell are optimized starting from random values. The PDF is obtained from carefully measured X-ray powder diffraction data. The method resembles `real-space' methods for structure solution from powder data, but works with PDF data instead of the diffraction pattern itself. As such it may be used in situations where the organic compounds are not long-range-ordered, are poorly crystalline, or nanocrystalline. The procedure was applied to solve and refine the crystal structures of quinacridone (β phase), naphthalene and allopurinol. In the case of allopurinol it was even possible to successfully solve and refine the structure in P1 with four independent molecules. As an example of a flexible molecule, the crystal structure of paracetamol was refined using restraints for bond lengths, bond angles and selected torsion angles. In all cases, the resulting structures are in excellent agreement with structures from single-crystal data.

  11. The use of potassium hydroxide (KOH) solution as a suitable approach to isolate plastics ingested by marine organisms

    NARCIS (Netherlands)

    Kühn, Susanne; Werven, Van Bernike; Oyen, Van Albert; Meijboom, André; Bravo Rebolledo, Elisa L.; Franeker, Van Jan A.

    2017-01-01

    In studies of plastic ingestion by marine wildlife, visual separation of plastic particles from gastrointestinal tracts or their dietary content can be challenging. Earlier studies have used solutions to dissolve organic materials leaving synthetic particles unaffected. However, insufficient tests h

  12. The Relationship between Environmental Turbulence, Management Support, Organizational Collaboration, Information Technology Solution Realization, and Process Performance, in Healthcare Provider Organizations

    Science.gov (United States)

    Muglia, Victor O.

    2010-01-01

    The Problem: The purpose of this study was to investigate relationships between environmental turbulence, management support, organizational collaboration, information technology solution realization, and process performance in healthcare provider organizations. Method: A descriptive/correlational study of Hospital medical services process…

  13. The use of potassium hydroxide (KOH) solution as a suitable approach to isolate plastics ingested by marine organisms

    NARCIS (Netherlands)

    Kühn, Susanne; Werven, Van Bernike; Oyen, Van Albert; Meijboom, André; Bravo Rebolledo, Elisa L.; Franeker, Van Jan A.

    2017-01-01

    In studies of plastic ingestion by marine wildlife, visual separation of plastic particles from gastrointestinal tracts or their dietary content can be challenging. Earlier studies have used solutions to dissolve organic materials leaving synthetic particles unaffected. However, insufficient tests h

  14. Charge injection in solution-processed organic field-effect transistors: physics, models and characterization methods.

    Science.gov (United States)

    Natali, Dario; Caironi, Mario

    2012-03-15

    A high-mobility organic semiconductor employed as the active material in a field-effect transistor does not guarantee per se that expectations of high performance are fulfilled. This is even truer if a downscaled, short channel is adopted. Only if contacts are able to provide the device with as much charge as it needs, with a negligible voltage drop across them, then high expectations can turn into high performances. It is a fact that this is not always the case in the field of organic electronics. In this review, we aim to offer a comprehensive overview on the subject of current injection in organic thin film transistors: physical principles concerning energy level (mis)alignment at interfaces, models describing charge injection, technologies for interface tuning, and techniques for characterizing devices. Finally, a survey of the most recent accomplishments in the field is given. Principles are described in general, but the technologies and survey emphasis is on solution processed transistors, because it is our opinion that scalable, roll-to-roll printing processing is one, if not the brightest, possible scenario for the future of organic electronics. With the exception of electrolyte-gated organic transistors, where impressively low width normalized resistances were reported (in the range of 10 Ω·cm), to date the lowest values reported for devices where the semiconductor is solution-processed and where the most common architectures are adopted, are ∼10 kΩ·cm for transistors with a field effect mobility in the 0.1-1 cm(2)/Vs range. Although these values represent the best case, they still pose a severe limitation for downscaling the channel lengths below a few micrometers, necessary for increasing the device switching speed. Moreover, techniques to lower contact resistances have been often developed on a case-by-case basis, depending on the materials, architecture and processing techniques. The lack of a standard strategy has hampered the progress of the

  15. Efficient green phosphorescent tandem organic light emitting diodes with solution processable mixed hosts charge generating layer

    Energy Technology Data Exchange (ETDEWEB)

    Talik, N.A.; Yeoh, K.H.; Ng, C.Y.B [Low Dimensional Research Center, Department of Physics, University Malaya, 50603 Kuala Lumpur (Malaysia); ItraMAS Corporation. Sdn. Bhd., 542A-B Mukim 1, Lorong Perusahaan Baru 2, Kawasan Perindustrian, Perai 13600, Penang (Malaysia); Yap, B.K. [Center of Microelectronic and Nanotechnology Engineering (CeMNE), College of Engineering, Universiti Tenaga Nasional, Jln. Uniten-Ikram, 4300 Kajang, Selangor (Malaysia); Woon, K.L., E-mail: ph7klw76@um.edu.my [Low Dimensional Research Center, Department of Physics, University Malaya, 50603 Kuala Lumpur (Malaysia)

    2014-10-15

    A novel solution processable charge generating layer (CGL) that consists of 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HATCN{sub 6})/Poly(N-vinylcarbazole) (PVK): 1,1-bis-(4-bis(4-tolyl)-aminophenyl) cyclohexene (TAPC) for a tandem green phosphorescent organic light emitting diode (PHOLED) is demonstrated. The use of orthogonal solvent to dissolve HATCN{sub 6} and PVK:TAPC is the key to overcome the interface erosion problem for the solution processed CGL. The current efficiency of the 2 wt% TAPC mixed with PVK is the highest at 24.2 cd/A, which is more than three-folds higher than that of the single device at 1000 cd/m{sup 2}. - Highlights: • A solution processable tandem OLED is built using a novel charge generating layer. • HATCN{sub 6} and PVK:TAPC are shown to be effective charge generating layers. • The turn on voltages for tandem devices are almost similar to single unit. • 2 wt% TAPC blended with PVK exhibits three-folds increase in efficiency.

  16. Effects of Chromophoric Dissolved Organic Matter on Anthracene Photolysis Kinetics in Aqueous Solution and Ice.

    Science.gov (United States)

    Malley, Philip P A; Grossman, Jarod N; Kahan, Tara F

    2017-09-27

    We measured photolysis kinetics of the PAH anthracene in aqueous solution, in bulk ice, and at ice surfaces in the presence and absence of chromophoric dissolved organic matter (CDOM). Self-association, which occurs readily at ice surfaces, may be responsible for the faster anthracene photolysis observed there. Photolysis rate constants in liquid water increased under conditions where anthracene self-association was observed. Concomitantly, kinetics changed from first-order to second-order, indicating that the photolysis mechanism at ice surfaces might be different than that in aqueous solution. Other factors that could lead to faster photolysis at ice surfaces were also investigated. Increased photon fluxes due to scattering in the ice samples can account for at most 20% of the observed rate increase, and other factors including singlet oxygen ((1)O2*) production and changes in pH and polarity were determined not to be responsible for the faster photolysis. CDOM (in the form of fulvic acid (FA)) did not affect anthracene photolysis kinetics in aqueous solution but suppressed photolysis in ice cubes and ice granules (by 30% and 56%, respectively). This was primarily due to competitive photon absorption (the inner filter effect). Freeze-concentration (or "salting out") appears to slightly increase the suppressing effects of FA on anthracene photolysis. This may be due to increased competitive photon absorption or to physical interactions between anthracene and FA.

  17. Low-temperature solution-processed graphene oxide derivative hole transport layer for organic solar cells

    Science.gov (United States)

    Zheng, Qiao; Fang, Guojia; Cheng, Fei; Lei, Hongwei; Qin, Pingli; Zhan, Caimao

    2013-04-01

    A Mo6+ cation modified graphene oxide (GO) derivative of GO-Mo was synthesized by a low-temperature solution method with different amounts of ammonium heptamolybdate (Mo-precursor) added into the GO solutions. The GO-Mo products were characterized through Raman microspectroscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy measurements and their photoelectric properties were systematically investigated. Organic bulk heterojunction solar cells with GO-Mo as the hole transport layer (HTL) were fabricated and their performance as a function of the number of GO-Mo layers was also studied. The performance of these devices was much better than that of the device with GO as the HTL. The best performance of the device with a power conversion efficiency of 2.61%, an open-circuit voltage of 0.59 V and a short-circuit current density of 9.02 mA cm-2 were obtained. Finally, the effect of the Mo-precursor weight in the GO solution on the device performance was discussed.

  18. Carbon-dot organic surface modifier analysis by solution-state NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Philippidis, Aggelos; Spyros, Apostolos, E-mail: aspyros@chemistry.uoc.gr; Anglos, Demetrios [University of Crete, NMR Laboratory, Department of Chemistry (Greece); Bourlinos, Athanasios B. [University of Ioannina, Physics Department (Greece); Zboril, Radek [Palacky University in Olomouc, Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science (Czech Republic); Giannelis, Emmanuel P. [Cornell University, Department of Materials Science and Engineering (United States)

    2013-07-15

    Carbon dots (C-dots) represent a new class of carbon-based materials that were discovered recently and have drawn the interest of the scientific community, particularly because of their attractive optical properties and their potential as fluorescent sensors. Investigation of the chemical structure of C-dots is extremely important for correlating the surface modifier composition with C-dot optical properties and allow for structure-properties fine tuning. In this article, we report the structural analysis of the surface modifiers of three different types of C-dot nanoparticles (Cwax, Cws, and Csalt) by use of 1D- and 2D-high-resolution NMR spectroscopy in solution. We unambiguously verify that the structure of the modifier chains remains chemically unchanged during the passivation procedure, and confirm the covalent attachment of the modifiers to the nanoparticle core, which contributes no signal to the solution-state NMR spectra. To our knowledge, this is the first study confirming the full structural assignment of C-dot organic surface modifiers by use of solution NMR spectroscopy.

  19. In situ analysis of the interfacial reactions between MCMB electrode and organic electrolyte solutions

    Science.gov (United States)

    Morigaki, Ken-ichi

    The interfacial phenomena between graphite (mesocarbon-microbeads (MCMB)) electrode and organic electrolyte solution were analyzed by in situ atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. The influence of lithium salts (anion species), LiPF 6, LiBF 4, and LiClO 4, on the interfacial reaction, including lithium intercalation into graphite, was investigated in EC+DMC solutions. In situ AFM observation disclosed that morphological changes are quite different from one another depending on the kind of lithium salt (anion). A large expansion of MCMB particle was observed particularly in LiPF 6/EC+DMC. An expansion of MCMB particle started above 1.0 V versus Li/Li + and this expansion seemed to be caused by the decomposition of ternary graphite intercalation compound (GIC) ( C nLi(sol) y), because the expansion remained after de-intercalation of lithium. IRAS spectra of each electrolyte solution showed different behaviors and different reduction products of solvents. double modulation FTIR (DMFTIR) spectra on graphite electrode, which emphasize the surface species, indicated relatively small changes after cathodic polarization. Therefore, the observed morphological changes were caused mainly by the expansion of graphene layers and not by the precipitation of reduction products.

  20. Characterization of the thermotropic behavior and lateral organization of lipid-peptide mixtures by a combined experimental and theoretical approach: Effects of hydrophobic mismatch and role of flanking residues

    DEFF Research Database (Denmark)

    Morein, S.; Killian, J.A.; Sperotto, Maria Maddalena

    2002-01-01

    , of variable length, of alternating leucine and alanine residues, flanked on both ends with tryptophan and lysine residues, respectively. By systematically varying the peptide hydrophobic length it was thus possible to explore different matching conditions between the peptide's hydrophobic length and the lipid...... bilayer hydrophobic thickness, and to investigate the potential role of flanking residues. The results show that both the WALP and the KALP peptides tend to favor the liquid-crystal line (or fluid) phase of the system; i.e., they tend to depress the main-transition temperature, T-m, of pure DPPC. However...

  1. Hydrophobic features of EPS extracted from anaerobic granular sludge: an investigation based on DAX-8 resin fractionation and size exclusion chromatography.

    Science.gov (United States)

    Cao, Feishu; Bourven, Isabelle; Lens, Piet N L; van Hullebusch, Eric D; Pechaud, Yoan; Guibaud, Gilles

    2017-04-01

    The hydrophobic fractionation of extracellular polymeric substances (EPS) extracted from anaerobic granular sludge was performed on the DAX-8 resin (two elution pH conditions, i.e., pH 2 and pH 5 were tested). The impact of seven different EPS extraction methods on EPS hydrophobicity features was assessed. The results showed that the extraction methods and bulk solution pH influenced dramatically the biochemical composition of the EPS, and in turn, the hydrophobicity determined. Besides, EPS extracting reagents i.e., formaldehyde, ethanol, sodium dodecyl sulfate (SDS), and Tween 20 not only introduced extra carbon content in the total organic carbon (TOC) measurement but also interacted with the DAX-8 resin. By comparing the apparent molecular weight (aMW) distribution of untreated and pH-adjusted EPS samples, more complete EPS aMW information was preserved at pH 5. Thus, elution at pH 5 was preferred in this study for the qualitative analysis of EPS hydrophobic features. The hydrophobic fraction of EPS retained by the resin at pH 5 was ascribed to a wide aMW range, ranging from >440 to 0.3 kDa. Within this range, EPS molecules ranging from 175 to 31 kDa were mostly retained by the DAX-8 resin, which indicates that these EPS molecules are highly hydrophobic.

  2. On the possibility of controlling the hydrophilic/hydrophobic characteristics of toroid Mo138 nanocluster polyoxometalates

    Science.gov (United States)

    Grzhegorzhevskii, K. V.; Adamova, L. V.; Eremina, E. V.; Ostroushko, A. A.

    2017-03-01

    The possibility of changing the hydrophilic (polar) surfaces of toroid nanocluster polyoxomolibdates to hydrophobic (nonpolar) surfaces via the modification of Mo138 nanoclusters by surfactant molecules (dodecylpyridinium chloride) as a result of the interaction between these compounds in solutions is demonstrated. Benzene and methanol are used as molecular probes (indicators of the condition of nanocluster surfaces). Comparative characteristics of the equilibrium sorption of benzene and methanol vapors on the initial and modified surfaces of the solid polyoxometalate, and data on the sorption of organic molecules on the surfaces of Rhodamine B-modified nanoclusters of the toroid (Mo138) and keplerate (Mo132) types are obtained.

  3. Selective adsorption and separation of organic dyes from aqueous solution on polydopamine microspheres.

    Science.gov (United States)

    Fu, Jianwei; Xin, Qianqian; Wu, Xuechen; Chen, Zhonghui; Yan, Ya; Liu, Shujun; Wang, Minghuan; Xu, Qun

    2016-01-01

    Polydopamine (PDA) microspheres, synthesized by a facile oxidation polymerization route, were evaluated as a potential adsorbent for selective adsorption and separation of organic dyes. The adsorption processes towards nine water-soluble dyes (anionic dyes: methyl orange (MO), eosin-Y (EY), eosin-B (EB), acid chrome blue K (ACBK), neutral dye: neutral red (NR), and cationic dyes: rhodamine B (RhB), malachite green (MG), methylene blue (MB), safranine T (ST)) were thoroughly investigated. The adsorption selectivity of organic dyes onto PDA microspheres was successfully applied for the separation of dyes mixtures. Various influential factors such as solution pH, temperature, and contact time were employed to ascertain the optimal condition for adsorption of representative organic dyes including MB, MG and NR. The pseudo-first-order and pseudo-second-order kinetics models were used to fit the adsorption kinetics process. Five isothermal adsorption models (Langmuir, Dubnin-Radushkevich, Temkin, Freundlich and Harkins-Jura) were used to investigate the adsorption thermodynamics properties. The results showed that the PDA microspheres owned good selective adsorption ability towards cationic dyes. The adsorption kinetics process conformed to the pseudo-second-order kinetics model and the Langmuir isotherm model was more appropriate for tracing the adsorption behavior than other isotherm models. Thus, we can conclude PDA microspheres may be a high-efficiency selective adsorbent towards some cationic dyes. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Solution-grown organic single-crystalline donor-acceptor heterojunctions for photovoltaics.

    Science.gov (United States)

    Li, Hanying; Fan, Congcheng; Fu, Weifei; Xin, Huolin L; Chen, Hongzheng

    2015-01-12

    Organic single crystals are ideal candidates for high-performance photovoltaics due to their high charge mobility and long exciton diffusion length; however, they have not been largely considered for photovoltaics due to the practical difficulty in making a heterojunction between donor and acceptor single crystals. Here, we demonstrate that extended single-crystalline heterojunctions with a consistent donor-top and acceptor-bottom structure throughout the substrate can be simply obtained from a mixed solution of C60 (acceptor) and 3,6-bis(5-(4-n-butylphenyl)thiophene-2-yl)-2,5-bis(2-ethylhexyl)pyrrolo[3,4-c]pyrrole-1,4-dione (donor). 46 photovoltaic devices were studied with the power conversion efficiency of (0.255±0.095)% under 1 sun, which is significantly higher than the previously reported value for a vapor-grown organic single-crystalline donor-acceptor heterojunction (0.007%). As such, this work opens a practical avenue for the study of organic photovoltaics based on single crystals.

  5. Phenylalanine containing hydrophobic nanospheres for antibody purification.

    Science.gov (United States)

    Türkmen, Deniz; Denizli, Adil; Oztürk, Nevra; Akgöl, Sinan; Elkak, Assem

    2008-01-01

    In this study, novel hydrophobic nanospheres with an average size of 158 nm utilizing N-methacryloyl-(L)-phenylalanine methyl ester (MAPA) as a hydrophobic monomer were produced by surfactant free emulsion polymerization of 2-hydroxyethyl methacrylate (HEMA) and MAPA conducted in an aqueous dispersion medium. MAPA was synthesized using methacryloyl chloride and L-phenylalanine methyl ester. Specific surface area of the nonporous nanospheres was found to be 1874 m2/g. Poly(HEMA-MAPA) nanospheres were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Average particle size, size distribution, and surface charge measurements were also performed. Elemental analysis of MAPA for nitrogen was estimated as 0.42 mmol/g polymer. Then, poly(HEMA-MAPA) nanospheres were used in the adsorption of immunoglobulin G (IgG) in batch system. Higher adsorption values (780 mg/g) were obtained when the poly (HEMA-MAPA) nanospheres were used from both aqueous solutions and human plasma. The adsorption phenomena appeared to follow a typical Langmuir isotherm. It was observed that IgG could be repeatedly adsorbed and desorbed without significant loss in adsorption amount. These findings show considerable promise for this material as a hydrophobic support in industrial processes.

  6. Hyperaggregating effect of hydroxyethyl starch components and University of Wisconsin solution on human red blood cells : A risk of impaired graft perfusion in organ procurement?

    NARCIS (Netherlands)

    Morariu, AM; Van der Plaats, A; Oeveren, WV; 'T Hart, NA; Leuvenink, HGD; Graaff, R; Ploeg, RJ; Rakhorst, G

    2003-01-01

    Background. The standard preservation solution used during organ procurement and preservation of most organs is the University of Wisconsin (UW) solution. Despite its superiority over other cold storage solutions, the inclusion of hydroxyethyl starch (HES) as one of the components of the UW solution

  7. X-ray imager using solution processed organic transistor arrays and bulk heterojunction photodiodes on thin, flexible plastic substrate

    NARCIS (Netherlands)

    Gelinck, G.H.; Kumar, A.; Moet, D.; Steen, J.L. van der; Shafique, U.; Malinowski, P.E.; Myny, K.; Rand, B.P.; Simon, M.; Rütten, W.; Douglas, A.; Jorritsma, J.; Heremans, P.L.; Andriessen, H.A.J.M.

    2013-01-01

    We describe the fabrication and characterization of large-area active-matrix X-ray/photodetector array of high quality using organic photodiodes and organic transistors. All layers with the exception of the electrodes are solution processed. Because it is processed on a very thin plastic substrate o

  8. Modifying the organic/electrode interface in Organic Solar Cells (OSCs) and improving the efficiency of solution-processed phosphorescent Organic Light-Emitting Diodes (OLEDs)

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Teng [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    thin LiF layer serves typically as the electron injection layer in OLEDs and electron collection interlayer in the OSCs. However, several reports showed that it can also assist in holeinjection in OLEDs. Here we first demonstrate that it assists hole-collection in OSCs, which is more obvious after air-plasma treatment, and explore this intriguing dual role. For OLEDs, we focus on solution processing methods to fabricate highly efficient phosphorescent OLEDs. First, we investigated OLEDs with a polymer host matrix, and enhanced charge injection by adding hole- and electron-transport materials into the system. We also applied a hole-blocking and electron-transport material to prevent luminescence quenching by the cathode. Finally, we substituted the polymer host by a small molecule, to achieve more efficient solution processed small molecular OLEDs (SMOLEDs); this approach is cost-effective in comparison to the more common vacuum thermal evaporation. All these studies help us to better understand the underlying relationship between the organic semiconductor materials and the OSCs and OLEDs’ performance and will subsequently assist in further enhancing the efficiencies of OSCs and OLEDs. With better efficiency and longer lifetime, the OSCs and OLEDs will be competitive with their inorganic counterparts.

  9. Responsive gelation of hydrophobized linear polymer

    DEFF Research Database (Denmark)

    Madsen, Claus Greve; Toeth, Joachim; Jørgensen, Lene;

    In this study we present the rheological properties of a physically linked polymer network, composed of linear hydrophilic chains, modified with hydrophobic moieties in each end. Solutions of the polymer in ethanol-water mixtures showed Newtonian behaviour up to about 99 % ethanol, with the highest...... viscosity observed in a 1:1 mixture of ethanol and water. In pure ethanol, the polymer forms a thermo-responsive, non-Newtonian gel, which collapses upon addition of as little as 1 % water or heating to about 40 °C....

  10. SOLUTIONING

    Directory of Open Access Journals (Sweden)

    Maria de Hoyos Guajardo, Ph.D. Candidate, M.Sc., B.Eng.

    2004-11-01

    Full Text Available The theory that is presented below aims to conceptualise how a group of undergraduate students tackle non-routine mathematical problems during a problem-solving course. The aim of the course is to allow students to experience mathematics as a creative process and to reflect on their own experience. During the course, students are required to produce a written ‘rubric’ of their work, i.e., to document their thoughts as they occur as well as their emotionsduring the process. These ‘rubrics’ were used as the main source of data.Students’ problem-solving processes can be explained as a three-stage process that has been called ‘solutioning’. This process is presented in the six sections below. The first three refer to a common area of concern that can be called‘generating knowledge’. In this way, generating knowledge also includes issues related to ‘key ideas’ and ‘gaining understanding’. The third and the fourth sections refer to ‘generating’ and ‘validating a solution’, respectively. Finally, once solutions are generated and validated, students usually try to improve them further before presenting them as final results. Thus, the last section deals with‘improving a solution’. Although not all students go through all of the stages, it may be said that ‘solutioning’ considers students’ main concerns as they tackle non-routine mathematical problems.

  11. Method for producing hydrophobic aerogels

    Science.gov (United States)

    Hrubesh, Lawrence W.; Poco, John F.; Coronado, Paul R.

    1999-01-01

    A method for treating a dried monolithic aerogel containing non-dispersed particles, with an organometallic surface modifying agent to produce hydrophobic aerogels. The dried, porous hydrophobic aerogels contain a protective layer of alkyl groups, such as methyl groups, on the modified surfaces of the pores of the aerogel. The alkyl groups at the aerogel surface typically contain at least one carbon-metal bond per group.

  12. Coadsorption of organic cations and different anions at the solution/mercury and solution/air interface

    Energy Technology Data Exchange (ETDEWEB)

    Damaskin, B.B.; Gerovich, V.M.; Podgornaya, M.I.

    1986-07-01

    The adsorption of tetraethylammonium ions was studied in the presence of anions SO/sub 4//sup 2 -/, Br/sup -/, and I/sup -/ at the solution/mercury interface by measuring capillary curves, and at the solution/air interface by measuring the maximum pressure in air bubbles. It was concluded from the potential dependence of adsorption energy that two potentials of maximum adsorption exist in the case of TEA bromide and TEA iodide; they are associated with two different orientations of the ion pairs TEA cation-halide anion in the compact double-layer part.

  13. Solution-Processing of Organic Solar Cells: From In Situ Investigation to Scalable Manufacturing

    KAUST Repository

    Abdelsamie, Maged

    2016-12-05

    Photovoltaics provide a feasible route to fulfilling the substantial increase in demand for energy worldwide. Solution processable organic photovoltaics (OPVs) have attracted attention in the last decade because of the promise of low-cost manufacturing of sufficiently efficient devices at high throughput on large-area rigid or flexible substrates with potentially low energy and carbon footprints. In OPVs, the photoactive layer is made of a bulk heterojunction (BHJ) layer and is typically composed of a blend of an electron-donating (D) and an electron-accepting (A) materials which phase separate at the nanoscale and form a heterojunction at the D-A interface that plays a crucial role in the generation of charges. Despite the tremendous progress that has been made in increasing the efficiency of organic photovoltaics over the last few years, with power conversion efficiency increasing from 8% to 13% over the duration of this PhD dissertation, there have been numerous debates on the mechanisms of formation of the crucial BHJ layer and few clues about how to successfully transfer these lessons to scalable processes. This stems in large part from a lack of understanding of how BHJ layers form from solution. This lack of understanding makes it challenging to design BHJs and to control their formation in laboratory-based processes, such as spin-coating, let alone their successful transfer to scalable processes required for the manufacturing of organic solar cells. Consequently, the OPV community has in recent years sought out to better understand the key characteristics of state of the art lab-based organic solar cells and made efforts to shed light on how the BHJ forms in laboratory-based processes as well as in scalable processes. We take the view that understanding the formation of the solution-processed bulk heterojunction (BHJ) photoactive layer, where crucial photovoltaic processes take place, is the one of the most crucial steps to developing strategies towards the

  14. Charge generation layers for solution processed tandem organic light emitting diodes with regular device architecture.

    Science.gov (United States)

    Höfle, Stefan; Bernhard, Christoph; Bruns, Michael; Kübel, Christian; Scherer, Torsten; Lemmer, Uli; Colsmann, Alexander

    2015-04-22

    Tandem organic light emitting diodes (OLEDs) utilizing fluorescent polymers in both sub-OLEDs and a regular device architecture were fabricated from solution, and their structure and performance characterized. The charge carrier generation layer comprised a zinc oxide layer, modified by a polyethylenimine interface dipole, for electron injection and either MoO3, WO3, or VOx for hole injection into the adjacent sub-OLEDs. ToF-SIMS investigations and STEM-EDX mapping verified the distinct functional layers throughout the layer stack. At a given device current density, the current efficiencies of both sub-OLEDs add up to a maximum of 25 cd/A, indicating a properly working tandem OLED.

  15. Solution-processed organic photovoltaic cells based on a squaraine dye.

    Science.gov (United States)

    Chen, Guo; Sasabe, Hisahiro; Wang, Zhongqiang; Wang, Xiaofeng; Hong, Ziruo; Kido, Junji; Yang, Yang

    2012-11-14

    In this work, 2,4-bis[4-(N,N-diisobutylamino)-2,6-dihydroxyphenyl] squaraine (SQ) was systematically studied as an electron donor in solution processed photovoltaic cells, showing power conversion efficiency of >4.0% under AM1.5G 1 sun illumination at room temperature. Low mobilities were found to limit charge transport in the bulk heterojunctions. Efficiency was thus improved to 5.1% at 80 °C mainly due to improvement of photocurrent extraction. We also demonstrated that the SQ compound synthesized via a simple method has high purity, and thus can be used in photovoltaic cells without further purification. Our results suggest the huge potential of SQ and its analogs in organic photovoltaic applications.

  16. Tuning the Microcavity of Organic Light Emitting Diodes by Solution Processable Polymer-Nanoparticle Composite Layers.

    Science.gov (United States)

    Preinfalk, Jan B; Schackmar, Fabian R; Lampe, Thomas; Egel, Amos; Schmidt, Tobias D; Brütting, Wolfgang; Gomard, Guillaume; Lemmer, Uli

    2016-02-01

    In this study, we present a simple method to tune and take advantage of microcavity effects for an increased fraction of outcoupled light in solution-processed organic light emitting diodes. This is achieved by incorporating nonscattering polymer-nanoparticle composite layers. These tunable layers allow the optimization of the device architecture even for high film thicknesses on a single substrate by gradually altering the film thickness using a horizontal dipping technique. Moreover, it is shown that the optoelectronic device parameters are in good agreement with transfer matrix simulations of the corresponding layer stack, which offers the possibility to numerically design devices based on such composite layers. Lastly, it could be shown that the introduction of nanoparticles leads to an improved charge injection, which combined with an optimized microcavity resulted in a maximum luminous efficacy increase of 85% compared to a nanoparticle-free reference device.

  17. Organ repair, hemostasis, and in vivo bonding of medical devices by aqueous solutions of nanoparticles.

    Science.gov (United States)

    Meddahi-Pellé, Anne; Legrand, Aurélie; Marcellan, Alba; Louedec, Liliane; Letourneur, Didier; Leibler, Ludwik

    2014-06-16

    Sutures are traumatic to soft connective tissues, such as liver or lungs. Polymer tissue adhesives require complex in vivo control of polymerization or cross-linking reactions and currently suffer from being toxic, weak, or inefficient within the wet conditions of the body. Herein, we demonstrate using Stöber silica or iron oxide nanoparticles that nanobridging, that is, adhesion by aqueous nanoparticle solutions, can be used in vivo in rats to achieve rapid and strong closure and healing of deep wounds in skin and liver. Nanoparticles were also used to fix polymer membranes to tissues even in the presence of blood flow, such as occurring after liver resection, yielding permanent hemostasis within a minute. Furthermore, medical devices and tissue engineering constructs were fixed to organs such as a beating heart. The simplicity, rapidity, and robustness of nanobridging bode well for clinical applications, surgery, and regenerative medicine.

  18. PEDOT:PSS Films with Metallic Conductivity through a Treatment with Common Organic Solutions of Organic Salts and Their Application as a Transparent Electrode of Polymer Solar Cells.

    Science.gov (United States)

    Yu, Zhimeng; Xia, Yijie; Du, Donghe; Ouyang, Jianyong

    2016-05-11

    A transparent electrode is an indispensable component of optoelectronic devices, and there as been a search for substitutes of indium tin oxide (ITO) as the transparent electrode. Poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) ( PSS) is a conducting polymer that is very promising as the next generation of materials for the transparent electrode if it can obtain conductivity as high as that of ITO. Here, we report the treatment of PSS with organic solutions to significantly enhance its conductivity. Common organic solvents like dimethylformamide and γ-butyrolactone and common organic salts like methylammonium iodide and methylammonium bromide are used for the organic solutions. The conductivity of pristine PSS films is only ∼0.2 S/cm, and it can be increased to higher than 2100 S/cm. The conductivity enhancement is much more significant than control treatments of PSS films with neat organic solvents or aqueous solutions of the organic salts. The mechanism for the conductivity enhancement is the synergetic effects of both the organic salts and organic solvents on the microstructure and composition of PSS. They induce the segregation of some PSSH chains from PSS. Highly conductive PSS films were studied as the transparent electrode of polymer solar cells. The photovoltaic efficiency is comparable to that with an ITO transparent electrode.

  19. Absorption of a volatile organic compound by a jet loop reactor with circulation of a surfactant solution: Performance evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byungjoon; Hwang, Geelsu; Haam, Seungjoo; Lee, Changha [Department of Chemical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Ahn, Ik-Sung [Department of Chemical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)], E-mail: iahn@yonsei.ac.kr; Lee, Kyoungjoo [Advanced Biotech Inc., Seoul (Korea, Republic of)

    2008-05-01

    Biofiltration shows high efficiency for the removal of industrial waste gases and reliable operational stability at low investment and operating cost, especially when the VOC concentration is low, such as 100 ppmv ({mu}L L{sup -1}) or less. However, it has been reported that the abrupt change in VOC concentrations leads to the failure of the biofilter. Hence, the pretreatment of waste gases is necessary to ensure the stable operation of the biofilter. The objective of this study is to develop a jet loop reactor (JLR) with circulation of a surfactant solution to lower the concentration of VOCs, especially hydrophobic VOCs. Toluene and Tween 81 were used as a model industrial waste gas and a surfactant, respectively. Among several non-ionic surfactants tested, Tween 81 showed the most rapid dissolution of toluene. When a JLR is replaced with fresh Tween 81 solution (0.3% w/v) every hour, it successfully absorbed for 48 h over 90% of the toluene in an inlet gas containing toluene at 1000 ppmv ({mu}L L{sup -1}) or less. Therefore, JLR with circulation of a surfactant solution is believed to ensure the stable operation of the biofilter even with the unexpected increase in the VOC concentrations.

  20. Lanthanide metal-organic frameworks as multifunctional luminescent sensor for detecting cations, anions and organic solvent molecules in aqueous solution

    Science.gov (United States)

    Liu, Feng; Gao, Wei; Li, Peng; Zhang, Xiu-Mei; Liu, Jie-Ping

    2017-09-01

    A series of water-stable isostructural mono/bimetallic lanthanide metal-organic frameworks (Ln-MOFs) {[Eu5xTb5(1-x)(OH)6(TZI)3(DMA)1.5(H2O)10.5]·DMA·0.5H2O}n (x = 1.0 (1), 0.5 (3), 0.4 (4), 0.3 (5), 0.2 (6), 0.1 (7), 0.05 (8), 0 (2), H3TZI = 5-(1H-tetrazol-5-yl)isophthalic acid) were synthesized. These Ln-MOFs exhibit 3D frameworks in which 1D chains based on pentanuclear [Ln5(μ3-OH)6(COO)5]4+ clusters are linked by TZI backbones. The luminescent investigations revealed that compounds 1 and 2 not only exhibit characteristic Eu3+ and Tb3+ emissions in the red and green regions, respectively, but also can sensitively and selectively detect Fe3+ cations, CO32-, PO43-, AsO43- anions and acetone molecules in aqueous solution. In addition, the luminescent colors of the bimetallic (Tb5(1-x):Eu5x) compounds can easily be tuned by doping isostructural Ln- MOFs with Eu3+ and Tb3+ ions. This work presents some good candidate materials for the potential multifunctional sensors. Eight water-stable isostructural 3D Ln-MOFs {[Eu5xTb5(1-x)(OH)6(TZI)3(DMA)1.5(H2O)10.5]·DMA·0.5H2O}n based on pentanuclear clusters were prepared. The Ln-MOFs represented the rapid and drastic emission quenching induced by Fe3+ cations, CO32-, PO43-, AsO43- anions and acetone molecules in aqueous solution. the luminescence colors of the bimetallic (Tb5(1-x):Eu5x) compounds can easily be tuned by doping isostructural Ln-MOFs with Eu3+ and Tb3+ ions.

  1. Perovskite light-emitting diodes based on solution-processed self-organized multiple quantum wells

    Science.gov (United States)

    Wang, Nana; Cheng, Lu; Ge, Rui; Zhang, Shuting; Miao, Yanfeng; Zou, Wei; Yi, Chang; Sun, Yan; Cao, Yu; Yang, Rong; Wei, Yingqiang; Guo, Qiang; Ke, You; Yu, Maotao; Jin, Yizheng; Liu, Yang; Ding, Qingqing; di, Dawei; Yang, Le; Xing, Guichuan; Tian, He; Jin, Chuanhong; Gao, Feng; Friend, Richard H.; Wang, Jianpu; Huang, Wei

    2016-11-01

    Organometal halide perovskites can be processed from solutions at low temperatures to form crystalline direct-bandgap semiconductors with promising optoelectronic properties. However, the efficiency of their electroluminescence is limited by non-radiative recombination, which is associated with defects and leakage current due to incomplete surface coverage. Here we demonstrate a solution-processed perovskite light-emitting diode (LED) based on self-organized multiple quantum wells (MQWs) with excellent film morphologies. The MQW-based LED exhibits a very high external quantum efficiency of up to 11.7%, good stability and exceptional high-power performance with an energy conversion efficiency of 5.5% at a current density of 100 mA cm-2. This outstanding performance arises because the lower bandgap regions that generate electroluminescence are effectively confined by perovskite MQWs with higher energy gaps, resulting in very efficient radiative decay. Surprisingly, there is no evidence that the large interfacial areas between different bandgap regions cause luminescence quenching.

  2. Effective Removal of Tetracycline from Aqueous Solution by Organic Acid-Coated Magnetic Nanoparticles.

    Science.gov (United States)

    Guo, Liang; Liang, Yuyan; Chen, Xuelan; Xu, Wei; Wu, Kesheng; Wei, Hua; Xiong, Yonghua

    2016-03-01

    Self-assembled iron oxide nanocomposites are good magnetic nano-adsorbents that can be prepared using simple methods. Four types of organic acid-functionalised (oleic acid, undecenoic acid, caprylic acid or hexanoic acid) magnetic nanoparticles (MNPs) were synthesised through a one-pot chemisorption method for the removal of tetracycline (TC) from aqueous solution. The undecenoic acid-coated MNPs (UA-MNPs) exhibited the highest adsorption efficiency and can be easily retrieved with a low-gradient magnetic separator (0.4 Tesla) at pH 5.0 aqueous solution. The TC adsorption process on the UA-MNPs followed the Langmuir isotherm and the maximum adsorption capacities increased from 86.96 mg g(-1) to 222.2 mg g(-1) with the increase in temperature from 288 K to 318 K. The kinetics of adsorption fits pseudo-second-order model perfectly with a rate constant, 5.946 g mg(-1) min(-1) at 298 K. The positive values of the enthalpy (AH) and the negative value of the free energy (AG) indicated an endothermic and spontaneous adsorption process of TC on the UA-MNPs. Moreover, the UA-MNPs possessed excellent ability to adsorb the other three major types of TC antibiotics, including chlortetracycline, oxytetracycline and doxycycline.

  3. Pyrrolidinone derivatives as processing additives for solution processed organic solar cells

    Science.gov (United States)

    Vongsaysy, Uyxing; Pavageau, Bertrand; Servant, Laurent; Aziz, Hany

    2014-10-01

    Processing additives are widely used to increase the efficiency of solution processed organic solar cells. We use the Hansen solubility parameters (HSPs) to investigate novel processing additives. The HSPs predict pyrrolidinone derivatives to be efficient processing additives for OSC systems based on poly(3-hexylthiophene)/[6,6]-phenyl-C61- butyric acid methyl ester (P3HT/PCBM). Two pyrrolidinone derivatives are identified: 1-methyl-2-pyrrolidinone and 1- benzyl-2-pyrrolidinone. The processing additives are introduced with various concentrations in the formulation of P3HT and PCBM solution. The electrical characterizations show that the two processing additives significantly increase the short circuit current and thus the power conversion efficiency of the OSCs. The results thus highlight HSPs as an effective and relatively straightforward tool that can be employed to optimize OSC morphology from a theoretical standpoint. Such a tool will be invaluable for identifying additives for novel high efficiency polymer species as they are synthesized, and thus to streamline the device fabrication and device optimization process.

  4. Thermally cross-linkable hole transport polymers for solution-based organic light-emitting diodes.

    Science.gov (United States)

    Cha, Seung Ji; Cho, Se-Na; Lee, Woo-Hyung; Chung, Ha-Seul; Kang, In-Nam; Suh, Min Chul

    2014-04-01

    Two thermally cross-linkable hole transport polymers that contain phenoxazine and triphenylamine moieties, X-P1 and X-P2, are developed for use in solution-processed multi-stack organic light-emitting diodes (OLEDs). Both X-P1 and X-P2 exhibit satisfactory cross-linking and optoelectronic properties. The highest occupied molecular orbital (HOMO) levels of X-P1 and X-P2 are -5.24 and -5.16 eV, respectively. Solution-processed super yellow polymer devices (ITO/X-P1 or X-P2/PDY-132/LiF/Al) with X-P1 or X-P2 hole transport layers of various thicknesses are fabricated with the aim of optimizing the device characteristics. The fabricated multi-stack yellow devices containing the newly synthesized hole transport polymers exhibit satisfactory currents and power efficiencies. The optimized X-P2 device exhibits a device efficiency that is dramatically improved by more than 66% over that of a reference device without an HTL.

  5. Adsorption and desorption of dissolved organic matter by carbon nanotubes: Effects of solution chemistry.

    Science.gov (United States)

    Engel, Maya; Chefetz, Benny

    2016-06-01

    Increasing use of carbon nanotubes (CNTs) has led to their introduction into the environment where they can interact with dissolved organic matter (DOM). This study focuses on solution chemistry effects on DOM adsorption/desorption processes by single-walled CNTs (SWCNTs). Our data show that DOM adsorption is controlled by the attachment of DOM molecules to the SWCNTs, and that the initial adsorption rate is dependent on solution parameters. Adsorbed amount of DOM at high ionic strength was limited, possibly due to alterations in SWCNT bundling. Desorption of DOM performed at low pH resulted in additional DOM adsorption, whereas at high pH, adsorbed DOM amount decreased. The extent of desorption conducted at increased ionic strength was dependent on pre-adsorbed DOM concentration: low DOM loading stimulated additional adsorption of DOM, whereas high DOM loading facilitated release of adsorbed DOM. Elevated ionic strength and increased adsorbed amount of DOM reduced the oxidation temperature of the SWCNTs, suggesting that changes in the assembly of the SWCNTs had occurred. Moreover, DOM-coated SWCNTs at increased ionic strength provided fewer sites for atrazine adsorption. This study enhances our understanding of DOM-SWCNT interactions in aqueous systems influenced by rapid changes in salinity, and facilitates potential use of SWCNTs in water-purification technologies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Studies of solution-processed organic light-emitting diodes and their materials

    Energy Technology Data Exchange (ETDEWEB)

    Hellerich, Emily [Iowa State Univ., Ames, IA (United States)

    2013-01-01

    A hitherto unexplored approach is presented in which a small molecule is used as a host to polymer guests in solution-processed OLEDs. We find that the small molecule host results in much more efficient devices than the often-used alternative polymer host when used for the guests presented. It is likely that nano- and microstructural differences between the hosts contribute to the improvements, which highlights some interesting characteristics that can help to better understand the nature of these mixtures. A number of the guests used in this study were newly synthesized benzobisoxazole-based copolymers. New organic copolymers are presented that are based on the chemical structure of benzobisoxazoles, which have been shown in the past to have good electron transporting properties. The novel concept in this publication pertains to a change in the direction of polymerization, also known as the conjugation pathway, which we show increases the emission efficiency. This work highlights a unique and useful property of organic semiconducting materials in that they can be synthesized to create the desired characteristics. Earlier work is described that kick-started in our research group the use of small molecules in solution-processed OLEDs. Originally these devices were to be used in magnetoresistance studies, but the project took a different path when the devices were more efficient than expected. The efficient use of small molecules in solution-processed OLEDs is highlighted, which at the time was not often the case. Also, the important observation of the effect of solvent choice on the resultant film is emphasized, with discussion of the likely cause of these effects. Microcavity OLEDs are introduced in which the transparent anode ITO is replaced with semi-transparent thin silver, which creates an optical cavity within the devices. The goal was to expand a previous work that created an on-chip spectrometer covering wavelengths 493 to 639 nm. In this case, a spin

  7. Optical properties and inclusion of an organic fluorophore in organized media of micellar solutions and beta-cyclodextrin

    Science.gov (United States)

    El-Sayed, Yusif S.

    2013-02-01

    In this study, we prepared a new chalcone compound (3-(4'-diethylaminophenyl)-1-(2-pyridinyl) prop-2-en-1-one abbreviated as DEAPPP) and examined its characterization and photophysical properties such as singlet absorption, molar absorptivity, fluorescence spectra, and fluorescence quantum yield (ϕf). DEAPPP dye exhibited a large red shift in both absorption and emission spectra as solvent polarity increases, indicating a large change in dipole moment of molecule upon excitation. Also, the fluorescence quantum yield was solvent dependent. The absorption and fluorescence emission spectral properties of DEAPPP have been investigated in organized media of aqueous micellar and β-cyclodextrin (CD) solutions. While the absorption spectra were less sensitive to the nature of the added surfactant or CD, the characteristics of the intramolecular charge transfer (ICT) fluorescence were highly sensitive to the properties of the medium. The ICT maximum was strongly blue-shifted with a great enhancement in the fluorescence quantum yield on adding micellar or CD. This indicated that the solubilization of DEAPPP increased in the micellar core and an inclusion complex with β-CD was formed. The critical micelle concentration (CMC) as well as the polarity of the micellar core of sodium dodecyl sulfate (SDS), Cetyltrimethylammonium bromide (CTAB) and Triton X-100 (TX-100) have been determined. The CMC values were in good agreement with the reported values while the polarity was lower indicating that DEAPPP molecules were incorporated in the micellar core not at the micellar interface. The binding constants of DEAPPP: micelles or DEAPPP: CD complexes have been also determined.

  8. Ferroelastic domain organization and precursor control of size in solution-grown hafnium dioxide nanorods.

    Science.gov (United States)

    Depner, Sean W; Cultrara, Nicholas D; Farley, Katie E; Qin, Yueling; Banerjee, Sarbajit

    2014-05-27

    We demonstrate that the degree of branching of the alkyl (R) chain in a Hf(OR)4 precursor allows for control over the length of HfO2 nanocrystals grown by homocondensation of the metal alkoxide with a metal halide. An extended nonhydrolytic sol-gel synthesis has been developed that enables the growth of high aspect ratio monoclinic HfO2 nanorods that grow along the [100] direction. The solution-grown elongated HfO2 nanorods show remarkable organization of twin domains separated by (100) coherent twin boundaries along the length of the nanowires in a morphology reminiscent of shape memory alloys. The sequence of finely structured twin domains each spanning only a few lattice planes originates from the Martensitic transformation of the nanorods from a tetragonal to a monoclinic structure upon cooling. Such ferroelastic domain organization is uncharacteristic of metal oxides and has not thus far been observed in bulk HfO2. The morphologies observed here suggest that, upon scaling to nanometer-sized dimensions, HfO2 might exhibit mechanical properties entirely distinctive from the bulk.

  9. Beyond Fullerenes: Designing Alternative Molecular Electron Acceptors for Solution-Processable Bulk Heterojunction Organic Photovoltaics.

    Science.gov (United States)

    Sauvé, Geneviève; Fernando, Roshan

    2015-09-17

    Organic photovoltaics (OPVs) are promising candidates for providing a low cost, widespread energy source by converting sunlight into electricity. Solution-processable active layers have predominantly consisted of a conjugated polymer donor blended with a fullerene derivative as the acceptor. Although fullerene derivatives have been the acceptor of choice, they have drawbacks such as weak visible light absorption and poor energy tuning that limit overall efficiencies. This has recently fueled new research to explore alternative acceptors that would overcome those limitations. During this exploration, one question arises: what are the important design principles for developing nonfullerene acceptors? It is generally accepted that acceptors should have high electron affinity, electron mobility, and absorption coefficient in the visible and near-IR region of the spectra. In this Perspective, we argue that alternative molecular acceptors, when blended with a conjugated polymer donor, should also have large nonplanar structures to promote nanoscale phase separation, charge separation and charge transport in blend films. Additionally, new material design should address the low dielectric constant of organic semiconductors that have so far limited their widespread application.

  10. Gate-induced superconductivity in a solution-processed organic polymer film.

    Science.gov (United States)

    Schön, J H; Dodabalapur, A; Bao, Z; Kloc, C; Schenker, O; Batlogg, B

    2001-03-08

    The electrical and optical properties of conjugated polymers have received considerable attention in the context of potentially low-cost replacements for conventional metals and inorganic semiconductors. Charge transport in these organic materials has been characterized in both the doped-metallic and the semiconducting state, but superconductivity has not hitherto been observed in these polymers. Here we report a distinct metal-insulator transition and metallic levels of conductivity in a polymer field-effect transistor. The active material is solution-cast regioregular poly(3-hexylthiophene), which forms relatively well ordered films owing to self-organization, and which yields a high charge carrier mobility (0.05-0.1 cm2 V(-1) s(-1)) at room temperature. At temperatures below approximately 2.35 K with sheet carrier densities exceeding 2.5 x 10(14) cm(-2), the polythiophene film becomes superconducting. The appearance of superconductivity seems to be closely related to the self-assembly properties of the polymer, as the introduction of additional disorder is found to suppress superconductivity. Our findings therefore demonstrate the feasibility of tuning the electrical properties of conjugated polymers over the largest range possible-from insulating to superconducting.

  11. Graphene nanosheets and graphite oxide as promising adsorbents for removal of organic contaminants from aqueous solution.

    Science.gov (United States)

    Ji, Liangliang; Chen, Wei; Xu, Zhaoyi; Zheng, Shourong; Zhu, Dongqiang

    2013-01-01

    Graphenes are an emerging class of carbon nanomaterials whose adsorption properties toward organic compounds have not been well understood. In the present study, graphene nanosheets were prepared by reoxidation and abrupt heating of graphite oxide, which was prepared by sequential chemical oxidation of commercial nonporous graphite powder. Adsorption properties of three aromatic compounds (naphthalene, 2-naphthol, and 1-naphthylamine) and one pharmaceutical compound (tylosin) on graphene nanosheets and graphite oxide were examined to explore the potential of these two adsorbents for the removal of organic contaminants from aqueous solutions. Compared with the literature data of adsorption on carbon nanotubes, adsorption of bulky, flexible tylosin on graphene nanosheets exhibited markedly faster adsorption kinetics, which can be attributed to their opened-up layer structure. Graphene nanosheets and graphite oxide showed similar sequences of adsorption affinity: 1-naphthylamine > 2-naphthol > tylosin > naphthalene (with much larger differences observed on graphite oxide). It was proposed that the strong adsorption of the three aromatic compounds was mainly due to π-π electron donor-acceptor interactions with the graphitic surfaces of adsorbents. Additionally, Lewis acid-base interaction was likely an important factor contributing to the strong adsorption of 1-naphthylamine and tylosin, especially for the O-functionality-abundant graphite oxide. After being normalized on the basis of adsorbent surface area, adsorption affinities of all four tested adsorbates on graphene nanosheets were very close to those on nonporous graphite powder, reflecting complete accessibility of the adsorbent surface area in adsorption.

  12. Photosensitized degradation of acetaminophen in natural organic matter solutions: The role of triplet states and oxygen.

    Science.gov (United States)

    Li, Yanyun; Pan, Yanheng; Lian, Lushi; Yan, Shuwen; Song, Weihua; Yang, Xin

    2017-02-01

    The photolysis of acetaminophen, a widely used pharmaceutical, in simulated natural organic matter solutions was investigated. The triplet states of natural organic matter ((3)NOM*) were found to play the dominant role in its photodegradation, while the contributions from hydroxyl radicals and singlet oxygen were negligible. Dissolved oxygen (DO) plays a dual role. From anaerobic to microaerobic (0.5 mg/L DO) conditions, the degradation rate of acetaminophen increased by 4-fold. That suggests the involvement of DO in reactions with the degradation intermediates. With increasing oxygen levels to saturated conditions (26 mg/L DO), the degradation rate became slower, mainly due to DO's quenching effect on (3)NOM*. Superoxide radical (O2(-)) did not react with acetaminophen directly, but possibly quenched the intermediates to reverse the degradation process. The main photochemical pathways were shown to involve phenoxyl radical and N-radical cations, finally yielding hydroxylated derivatives, dimers and nitrosophenol. A reaction mechanism involving (3)NOM*, oxygen and O2(-) is proposed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Hydrophobic mismatch sorts SNARE proteins into distinct membrane domains

    Science.gov (United States)

    Milovanovic, Dragomir; Honigmann, Alf; Koike, Seiichi; Göttfert, Fabian; Pähler, Gesa; Junius, Meike; Müllar, Stefan; Diederichsen, Ulf; Janshoff, Andreas; Grubmüller, Helmut; Risselada, Herre J.; Eggeling, Christian; Hell, Stefan W.; van den Bogaart, Geert; Jahn, Reinhard

    2015-01-01

    The clustering of proteins and lipids in distinct microdomains is emerging as an important principle for the spatial patterning of biological membranes. Such domain formation can be the result of hydrophobic and ionic interactions with membrane lipids as well as of specific protein-protein interactions. Here using plasma membrane-resident SNARE proteins as model, we show that hydrophobic mismatch between the length of transmembrane domains (TMDs) and the thickness of the lipid membrane suffices to induce clustering of proteins. Even when the TMDs differ in length by only a single residue, hydrophobic mismatch can segregate structurally closely homologous membrane proteins in distinct membrane domains. Domain formation is further fine-tuned by interactions with polyanionic phosphoinositides and homo and heterotypic protein interactions. Our findings demonstrate that hydrophobic mismatch contributes to the structural organization of membranes.

  14. Design and synthesis of molecular donors for solution-processed high-efficiency organic solar cells.

    Science.gov (United States)

    Coughlin, Jessica E; Henson, Zachary B; Welch, Gregory C; Bazan, Guillermo C

    2014-01-21

    Organic semiconductors incorporated into solar cells using a bulk heterojunction (BHJ) construction show promise as a cleaner answer to increasing energy needs throughout the world. Organic solar cells based on the BHJ architecture have steadily increased in their device performance over the past two decades, with power conversion efficiencies reaching 10%. Much of this success has come with conjugated polymer/fullerene combinations, where optimized polymer design strategies, synthetic protocols, device fabrication procedures, and characterization methods have provided significant advancements in the technology. More recently, chemists have been paying particular attention to well-defined molecular donor systems due to their ease of functionalization, amenability to standard organic purification and characterization methods, and reduced batch-to-batch variability compared to polymer counterparts. There are several critical properties for efficient small molecule donors. First, broad optical absorption needs to extend towards the near-IR region to achieve spectral overlap with the solar spectrum. Second, the low lying highest occupied molecular orbital (HOMO) energy levels need to be between -5.2 and -5.5 eV to ensure acceptable device open circuit voltages. Third, the structures need to be relatively planar to ensure close intermolecular contacts and high charge carrier mobilities. And last, the small molecule donors need to be sufficiently soluble in organic solvents (≥10 mg/mL) to facilitate solution deposition of thin films of appropriate uniformity and thickness. Ideally, these molecules should be constructed from cost-effective, sustainable building blocks using established, high yielding reactions in as few steps as possible. The structures should also be easy to functionalize to maximize tunability for desired properties. In this Account, we present a chronological description of our thought process and design strategies used in the development of highly

  15. Efficient adsorbents of nanoporous aluminosilicate monoliths for organic dyes from aqueous solution.

    Science.gov (United States)

    El-Safty, Sherif A; Shahat, Ahmed; Awual, Md Rabiul

    2011-07-01

    Growing public awareness on the potential risk to humans of toxic chemicals in the environment has generated demand for new and improved methods for toxicity assessment and removal, rational means for health risk estimation. With the aim of controlling nanoscale adsorbents for functionality in molecular sieving of organic pollutants, we fabricated cubic Im3m mesocages with uniform entrance and large cavity pores of aluminosilicates as highly promising candidates for the colorimetric monitoring of organic dyes in an aqueous solution. However, a feasible control over engineering of three-dimensional (3D) mesopore cage structures with uniform entrance (~5 nm) and large cavity (~10 nm) allowed the development of nanoadsorbent membranes as a powerful tool for large-quantity and high-speed (in minutes) adsorption/removal of bulk molecules such as organic dyes. Incorporation of high aluminum contents (Si/Al=1) into 3D cubic Im3m cage mesoporous silica monoliths resulted in small, easy-to-use optical adsorbent strips. In such adsorption systems, natural surfaces of active acid sites of aluminosilicate strips strongly induced both physical adsorption of chemically responsive dyes and intraparticle diffusion into cubic Im3m mesocage monoliths. Results likewise indicated that although aluminosilicate strips with low Si/Al ratios exhibit distortion in pore ordering and decrease in surface area and pore volume, enhancement of both molecular converges and intraparticle diffusion onto the network surfaces and into the pore architectures of adsorbent membranes was achieved. Moreover, 3D mesopore cage adsorbents are reversible, offering potential for multiple adsorption assays.

  16. 21 CFR 584.700 - Hydrophobic silicas.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hydrophobic silicas. 584.700 Section 584.700 Food... DRINKING WATER OF ANIMALS Listing of Specific Substances Affirmed as GRAS § 584.700 Hydrophobic silicas. (a) Product. Amorphous fumed hydrophobic silica or precipitated hydrophobic silica (CAS Reg. No....

  17. A review of some recently proposed modeling paradigms for the sorption of hydrophobic organic chemicals to heterogeneous carbonaceous matter in soils, sediments, and rocks -- the role of thermally altered carbon

    Science.gov (United States)

    Ball, W. P.; Allen-King, R. M.; Grathwohl, P.; Nguyen, T. H.; Brown, R. A.

    2003-04-01

    Heterogeneity of naturally occurring carbonaceous materials (CMs) in soils, sediments, and rocks causes the sorption of hydrophobic organic chemicals (HOCs) to occur as a combination of surface adsorption and phase partitioning, with the latter typically more linearly dependent on aqueous concentration. In particular, thermally altered CMs (such as wood char, soots, coals, and kerogen) are widespread in the environment and can serve as an important sorbents even when present in small quantities (especially at low concentrations of adsorbates). In this context, recent literature has presented models to simulate HOC sorption as the combined effect of adsorption to thermally altered CM and a more linear solvation-driven absorption into gel-like organic matter. We describe different forms of thermally altered CM, the manner in which these materials can serve as especially strong adsorbents, and the conditions under which they can control solid-aqueous distribution. Individual study with some well-characterized chars, coals, and soots have been conducted in our laboratories and provide some clear indications of the potential role of these materials in affecting overall contaminant uptake. Additionally, some specific examples of model fits to soil, sediment and rock samples with identified thermally altered CM components provide a linkage between such sorption components and sorbent material properties. Because both the adsorption and partition components are scalable by compound solubility, it may often be possible to provide estimates of nonlinear isotherms for a wide range of chemicals based on comparatively few experimental measurements using probe chemical sorbates. Although such a limited experimental study is not expected to provide a precise accounting of all aspects of adsorption and partitioning, we maintain that it will be clearly preferable to an a priori assumption of linear phase partitioning, and particularly so if enough information can be generated to

  18. Fluoroalkyl and Alkyl Chains Have Similar Hydrophobicities in Binding to the “Hydrophobic Wall” of Carbonic Anhydrase

    Energy Technology Data Exchange (ETDEWEB)

    J Mecinovic; P Snyder; K Mirica; S Bai; E Mack; R Kwant; D Moustakas; A Heroux; G Whitesides

    2011-12-31

    The hydrophobic effect, the free-energetically favorable association of nonpolar solutes in water, makes a dominant contribution to binding of many systems of ligands and proteins. The objective of this study was to examine the hydrophobic effect in biomolecular recognition using two chemically different but structurally similar hydrophobic groups, aliphatic hydrocarbons and aliphatic fluorocarbons, and to determine whether the hydrophobicity of the two groups could be distinguished by thermodynamic and biostructural analysis. This paper uses isothermal titration calorimetry (ITC) to examine the thermodynamics of binding of benzenesulfonamides substituted in the para position with alkyl and fluoroalkyl chains (H{sub 2}NSO{sub 2}C{sub 6}H{sub 4}-CONHCH{sub 2}(CX{sub 2}){sub n}CX{sub 3}, n = 0-4, X = H, F) to human carbonic anhydrase II (HCA II). Both alkyl and fluoroalkyl substituents contribute favorably to the enthalpy and the entropy of binding; these contributions increase as the length of chain of the hydrophobic substituent increases. Crystallography of the protein-ligand complexes indicates that the benzenesulfonamide groups of all ligands examined bind with similar geometry, that the tail groups associate with the hydrophobic wall of HCA II (which is made up of the side chains of residues Phe131, Val135, Pro202, and Leu204), and that the structure of the protein is indistinguishable for all but one of the complexes (the longest member of the fluoroalkyl series). Analysis of the thermodynamics of binding as a function of structure is compatible with the hypothesis that hydrophobic binding of both alkyl and fluoroalkyl chains to hydrophobic surface of carbonic anhydrase is due primarily to the release of nonoptimally hydrogen-bonded water molecules that hydrate the binding cavity (including the hydrophobic wall) of HCA II and to the release of water molecules that surround the hydrophobic chain of the ligands. This study defines the balance of enthalpic and

  19. Hydro-physical processes and soil properties correlated with origin of soil hydrophobicity

    Directory of Open Access Journals (Sweden)

    Eduardo Saldanha Vogelmann

    2013-09-01

    Full Text Available Hydrophobicity is the phenomenon where the soil has reduced wettability, usually associated with coating of soil particles by hydrophobic organic substances. This study aimed to provide a description of the hydrophobicity occurrence, highlight recent discoveries about the origin of phenomenon and discuss the main hydro-physical properties and chemical processes linked to the development of hydrophobic behavior in soils. Hydrophobicity is associated with other factors such as soil moisture, presence of some fungi species, particle size, soil pH and occurrence of burnings. The causative substances may be provided by local vegetation, through deposition or decomposition. The dependence and combination of different factors that influence hydrophobicity in soils lead to a spatial and temporal variability of the phenomenon, with negative consequences in the processes of infiltration and water percolation, affecting the three-dimensional distribution and dynamics of soil moisture. Thus, the occurrence of a hydrophobic character requires special attention, especially regarding soil use and management.

  20. Hydrophobic silica aerogel production at KEK

    CERN Document Server

    Tabata, Makoto; Kawai, Hideyuki; Sumiyoshi, Takayuki; Yokogawa, Hiroshi

    2011-01-01

    We present herein a characterization of a standard method used at the High Energy Accelerator Research Organization (KEK) to produce hydrophobic silica aerogels and expand this method to obtain a wide range of refractive index (n = 1.006-1.14). We describe in detail the entire production process and explain the methods used to measure the characteristic parameters of aerogels, namely the refractive index, transmittance, and density. We use a small-angle X-ray scattering (SAXS) technique to relate the transparency to the fine structure of aerogels.

  1. Hydrophobic effects on partial molar volume

    Science.gov (United States)

    Imai, Takashi; Hirata, Fumio

    2005-03-01

    The hydrophobic effects on partial molar volume (PMV) are investigated as a PMV change in the transfer of a benzenelike nonpolar solute from the nonpolar solvent to water, using an integral equation theory of liquids. The volume change is divided into two effects. One is the "packing" effect in the transfer from the nonpolar solvent to hypothetical "nonpolar water" without hydrogen bonding networks. The other is the "iceberg" effect in the transfer from nonpolar water to water. The results indicate that the packing effect is negative and a half compensated by the positive iceberg effect. The packing effect is explained by the difference in the solvent compressibility. Further investigation shows that the sign and magnitude of the volume change depend on the solute size and the solvent compressibility. The finding gives a significant implication that the exposure of a hydrophobic residue caused by protein denaturation can either increase or decrease the PMV of protein depending on the size of the residue and the fluctuation of its surroundings.

  2. Properties and influence of hydrophobically associating polyacrylamide modified with 2-phenoxylethylacrylate

    Institute of Scientific and Technical Information of China (English)

    Yu-hua DAI; Fei-peng WU; Miao-zhen LI; Er-jian WANG

    2008-01-01

    The properties of hydrophobically associating copolymer P(acrylamide (AM)/2-phenoxylethylacrylate (POEA)), composed of acrylamide and a small amount of POEA (≤1.0 mol.%) as hydrophobe, were investi-gated in aqueous solution under various conditions. The results showed that the solution properties were strongly affected by the microstructure of copolymer. The copoly-mers (BP series) with hydrophobic microblocky structure exhibited large viscosity enhancement due to the inter-molecular hydrophobic association, while that did not occur for the random copolymers (RP series). The hydro-phobic association thickening behaviors were also remarkably dependent on the number and length of the hydrophobic block in polymer chain. Nonlinear viscosity relationship was found as increasing hydrophobe content and SMR (surfactant/hydrophobic monomer molar ratio), and a maximum appeared at the middle position as a result of the competitive effect between inter- and intra- molecular hydrophobic associations. Solution properties were further studied as a function of the poly-mer concentration, salinity, temperature and shear rate. The block copolymers show high salt tolerance and shear thinning as well as recovery after shear.

  3. MS-2 and poliovirus transport in porous media: Hydrophobic effects and chemical perturbations

    Science.gov (United States)

    Bales, Roger C.; Li, Shimin; Maguire, Kimberly M.; Yahya, Moyasar T.; Gerba, Charles P.

    1993-04-01

    In a series of pH 7 continuous-flow column experiments, removal of the bacteriophage MS-2 by attachment to silica beads had a strong, systematic dependence on the amount of hydrophobic surface present on the beads. With no hydrophobic surface, removal of phage at pH 5 was much greater than at pH 7. Release of attached phage at both pH values did occur, but was slow; breakthrough curves exhibited tailing. Poliovirus attached to silica beads at pH 5.5 much more than at pH 7.0, and attachment was also slowly reversible. Time scales for phage and poliovinis attachment were of the order of hours. The sticking efficiency factor (α), reflecting microscaie physicochemical influences on virus attachment, was in the range of 0.0007-0.02. Phage release was small but measurable under steady state conditions. Release was enhanced by lowering ionic strength and by introducing beef extract, a high-ionic-strength protein solution. Results show that viruses experience reversible attachment/detachment (sometimes termed sorption), that large chemical perturbations are needed to induce rapid virus detachment, and that viruses should be quite mobile in sandy porous media. Even small amounts of hydrophobic organic material in the porous media (≥0.001%) can retard virus transport.

  4. Different assembly of type IV collagen on hydrophilic and hydrophobic substrata alters endothelial cells interaction.

    Science.gov (United States)

    Coelho, N Miranda; González-García, C; Planell, J A; Salmerón-Sánchez, M; Altankov, G

    2010-06-09

    Considering the structural role of type IV collagen (Col IV) in the assembly of the basement membrane (BM) and the perspective of mimicking its organization for vascular tissue engineering purposes, we studied the adsorption pattern of this protein on model hydrophilic (clean glass) and hydrophobic trichloro(octadecyl)silane (ODS) surfaces known to strongly affect the behavior of other matrix proteins. The amount of fluorescently labeled Col IV was quantified showing saturation of the surface for concentration of the adsorbing solution of about 50microg/ml, but with approximately twice more adsorbed protein on ODS. AFM studies revealed a fine - nearly single molecular size - network arrangement of Col IV on hydrophilic glass, which turns into a prominent and growing polygonal network consisting of molecular aggregates on hydrophobic ODS. The protein layer forms within minutes in a concentration-dependent manner. We further found that human umbilical vein endothelial cells (HUVEC) attach less efficiently to the aggregated Col IV (on ODS), as judged by the significantly altered cell spreading, focal adhesions formation and the development of actin cytoskeleton. Conversely, the immunofluorescence studies for integrins revealed that the fine Col IV network formed on hydrophilic substrata is better recognized by the cells via both alpha1 and alpha2 heterodimers which support cellular interaction, apart from these on hydrophobic ODS where almost no clustering of integrins was observed.

  5. Different assembly of type IV collagen on hydrophilic and hydrophobic substrata alters endothelial cells interaction

    Directory of Open Access Journals (Sweden)

    NM Coelho

    2010-06-01

    Full Text Available Considering the structural role of type IV collagen (Col IV in the assembly of the basement membrane (BM and the perspective of mimicking its organization for vascular tissue engineering purposes, we studied the adsorption pattern of this protein on model hydrophilic (clean glass and hydrophobic trichloro(octadecylsilane (ODS surfaces known to strongly affect the behavior of other matrix proteins. The amount of fluorescently labeled Col IV was quantified showing saturation of the surface for concentration of the adsorbing solution of about 50μg/ml, but with approximately twice more adsorbed protein on ODS. AFM studies revealed a fine – nearly single molecular size – network arrangement of Col IV on hydrophilic glass, which turns into a prominent and growing polygonal network consisting of molecular aggregates on hydrophobic ODS. The protein layer forms within minutes in a concentration-dependent manner. We further found that human umbilical vein endothelial cells (HUVEC attach less efficiently to the aggregated Col IV (on ODS, as judged by the significantly altered cell spreading, focal adhesions formation and the development of actin cytoskeleton. Conversely, the immunofluorescence studies for integrins revealed that the fine Col IV network formed on hydrophilic substrata is better recognized by the cells via both α1 and α2 heterodimers which support cellular interaction, apart from these on hydrophobic ODS where almost no clustering of integrins was observed.

  6. Comparison of physicomechanical properties of films prepared from organic solutions and aqueous dispersion of Eudragit RL

    Directory of Open Access Journals (Sweden)

    H Afrasiabi Garekani

    2011-05-01

    Full Text Available Background and the purpose of the study: Mechanical properties of films prepared from aqueous dispersion and organic solutions of Eudragit RL were assessed and the effects of plasticizer type, concentration and curing were examined. Methods: Films were prepared from aqueous dispersion and solutions of Eudragit RL (isopropyl alcohol-water 9:1 containing 0, 10 or 20% (based on polymer weight of PEG 400 or Triethyl Citrate (TEC as plasticizer using casting method. Samples of films were stored in oven at 60ºC for 24 hrs (Cured. The stress-strain curve was obtained for each film using material testing machine and tensile strength, elastic modulus, %elongation and work of failure were calculated. Results and major conclusion: The films with no plasticizer showed different mechanical properties depending on the vehicle used. Addition of 10% or 20% of plasticizer decreased the tensile strength and elastic modulus and increased %elongation and work of failure for all films. The effect of PEG400 on mechanical properties of Eudragit RL films was more pronounced. The differences in mechanical properties of the films due to vehicle decreased by addition of plasticizer and increase in its concentration. Curing process weakened the mechanical properties of the films with no plasticizer and for films with 10% plasticizer no considerable difference in mechanical properties was observed before and after curing. For those with 20% plasticizer only films prepared from aqueous dispersion showed remarkable difference in mechanical properties before and after curing. Results of this study suggest that the mechanical properties of the Eudragit RL films were affected by the vehicle, type of plasticizer and its concentration in the coating liquid.

  7. Estimation of atomic hydrophobicities using molecular dynamics simulation of peptides

    Science.gov (United States)

    Held, Marie; Nicolau, Dan V.

    2007-12-01

    The hydrophobic force is one of the main driving forces in protein folding and binding. However, its nature is not yet well understood and consequently there are more than 80 different scales published trying to quantify it. Most of the hydrophobicity scales are amino acid-based, but the interaction between the molecular surface of the proteins (and DNA) and surfaces they are immobilized on, e.g., on biomedical micro/nanodevices, occurs on fractions of, rather than whole amino acids. This fragmented structure of the biomolecular surface requires the derivation of atom-level hydrophobicity. Most attempts for the evaluation of atomic hydrophobicities are derived from amino acid-based values, which ignore dynamic and steric factors. This contribution reports on the Molecular Dynamics simulations that aim to overcome this simplification. The calculations examine various tripeptides in an aqueous solution and the analysis focuses on the distance of the nearest water molecules to the individual atoms in the peptides. Different environments result in a variation of average distances for similar atoms in different tripeptides. Comparison with the atomic hydrophobicities derived from the amino acid-based hydrophobicity obtained from peptide partition in water-octanol (Dgoct) and transport through the membrane interface (Dgwif) shows a similar trend to the calculated distances. The variations are likely due to the steric differences of similar types of atoms in different geometric contexts. Therefore, Molecular Dynamics simulations proved convenient for the evaluation of atomic hydrophobicities and open new research avenues. The atomic hydrophobicities can be used to design surfaces that mimic the biomolecular surfaces and therefore elicit an expected biomolecular activity from the immobilized biomolecules.

  8. Floating behavior of hydrophobic glass spheres.

    Science.gov (United States)

    Liu, Xinjie; Wang, Xiaolong; Liang, Yongmin; Zhou, Feng

    2009-08-15

    When a hydrophobic solid sphere is floating on water or salt solutions with different concentrations, it is at equilibrium under the impact of gravity, buoyancy force, and curvature force, the component of surface tension in the vertical direction. We have changed the diameters of the spheres and the concentrations of the two selected salts, NaCl and NaNO(3), to study the floating behaviors of these spheres and the contributions of surface tension and buoyancy force to their floatation. Generally speaking, the surface tension plays a more important role than the buoyancy force when the gravity is small, but the buoyancy force plays an identical or a more important role when the spheres are big enough. The wettability of the spheres significantly influences the height below the contact perimeter especially in salt solutions. The theoretical calculation meniscus slope angles at the sphere three-phase contact line are in agreement with experimental results.

  9. Development of adsorbents from used tire rubber. Their use in the adsorption of organic and inorganic solutes in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Troca-Torrado, Cesar; Alexandre-Franco, Maria; Fernandez-Gonzalez, Carmen; Gomez-Serrano, Vicente [Extremadura Univ., Badajoz (Spain). Dept. de Quimica Organica e Inorganica; Alfaro-Dominguez, Manuel [Extremadura Univ., Badajoz (Spain). Dept. de Ingenieria Mecanica, Energetica y de los Materiales

    2011-02-15

    Using used tire rubber (UTR), carbonaceous adsorbents (CAs) were prepared by chemical treatment of the material with HCl, HNO{sub 3} and NaOH aqueous solutions and by heat treatment at 900 C for 2 h in N{sub 2} atmosphere (H900). UTR and the UTR-derived products were first characterized in terms of texture by N{sub 2} adsorption at - 196 C and of oxygen surface groups by FT-IR spectroscopy and pH of the point of zero charge (pH{sub pzc}). Then, the products were tested as adsorbents of phenol, p-aminophenol, p-nitrophenol, and p-chlorophenol and of chromium, cadmium, mercury and lead in aqueous solution. The development of porosity is very poor in UTR and in the chemically treated products. H900 is the only CA with a better developed porosity, mainly in the regions of meso and macropores. pH{sub pzc} is close to 7.0 for most of the CAs. As an exception to the rule, pH{sub pzc} is 8.4 for H900. For this CA, the adsorption of all the adsorptives is greater. Usually, adsorption kinetics are fast. This is so in particular for p-nitrophenol and p-chlorophenol, on the one side, and for mercury and lead, on the other side. Adsorption is much higher for mercury and lead than for the remaining adsorptives. (author)

  10. Hydrophobic aggregation of ultrafine kaolinite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-ping; HU Yue-hua; LIU Run-Qing

    2008-01-01

    The hydrophobic aggregation of ultrafine kaolinite in cationic surfactant suspension was investigated by sedimentation test, zeta potential measurement and SEM observation. SEM images reveal that kaolinite particles show the self-aggregation of edge-face in acidic media, the aggregation of edge-face and edge-edge in neutral media, and the dispersion in alkaline media due to electrostatic repulsion. In the presence of the dodecylammonium acetate cationic surfactant and in neutral and alkaline suspension, the hydrophobic aggregation of face-face is demonstrated. The zeta potential of kaolinite increases with increasing the concentration of cationic surfactant. The small and loose aggregation at a low concentration but big and tight aggregation at a high concentration is presented At pH=7 alkyl quarterly amine salt CTAB has the best hydrophobic aggregation among three cationic surfactants, namely, dodecylammonium acetate, alkyl quarterly amine salts 1227 and CTAB.

  11. The dynamics of hydrophobic interaction : A microwave dielectric study

    NARCIS (Netherlands)

    Hallenga, Klaas

    1972-01-01

    To investigate the relation between the structure of liquid water and hydrophobic interaction the dielectric relaxation of water in dilute aqueous solutions has been studied. After an introduction of the problem in which the dynamic aspects of water structure are emphasized, a theoretical analysis o

  12. Measurements of activity coefficients at infinite dilution of organic solutes and water on polar imidazolium-based ionic liquids

    OpenAIRE

    Martins, Mónia A. R.; Coutinho, João A. P.; Pinho, Simão; Domańska, Urszula

    2015-01-01

    The activity coefficients at infinite dilution, gamma(infinity)(13), of 55 organic solutes and water in three ionic liquids with the common cation 1-butyl-3-methylimidazolium and the polar anions Cl--,Cl- [CH3SO3](-) and [(CH3)(2)PO4](-), were determined by (gas + liquid) chromatography at four temperatures in the range (358.15 to 388.15) K for alcohols and water, and T = (398.15 to 428.15) K for the other organic solutes including alkanes, cycloalkanes, alkenes, cycloalkenes, alkynes, ketone...

  13. Galvanic corrosion of Cu coupled to Au on a print circuit board; Effects of pretreatment solution and etchant concentration in organic solderability preservatives soft etching solution

    Science.gov (United States)

    Oh, SeKwon; Kim, YoungJun; Shon, MinYoung; Kwon, HyukSang

    2016-09-01

    In present study, we quantitatively define the galvanic corrosion phenomenon of Cu electrically coupled to Au on Print Circuit Board in Organic Solderability Preservatives (OSP) pretreatment (pickling and soft etching) solutions. As a result of polarization and ZRA test, galvanic corrosion rate of Cu in soft etching solution was about 3000 times higher than that of pickling solution. The oxone in OSP soft etching solution was acted as strong oxidant for Cu on PCB substrate. And the galvanic corrosion of Cu in OSP soft etching solution was examined with the change of etchants (oxone (KHSO5), sulfuric acid (H2SO4)) concentration. The galvanic corrosion rate of Cu was increased by the increase of the oxone and sulfuric acid concentrations, which lead to the increase of cathodic reactant such as HSO 5 - and H+ ions. And the degree of galvanic corrosion rate of Cu (Δisoft etching = icouple, (Cu-Au) - icorr, Cu) decreased with the decrease of the oxone and sulfuric acid concentrations.

  14. How microorganisms use hydrophobicity and what does this mean for human needs?

    Directory of Open Access Journals (Sweden)

    Anna eKrasowska

    2014-08-01

    Full Text Available Cell surface hydrophobicity (CSH plays a crucial role in the attachment to, or detachment from the surfaces. The influence of CSH on adhesion of microorganisms to biotic and abiotic surfaces in medicine as well as in bioremediation and fermentation industry has both negative and positive aspects. Hydrophobic microorganisms cause the damage of surfaces by biofilm formation; on the other hand, they can readily accumulate on organic pollutants and decompose them. Hydrophilic microorganisms also play a considerable role in removing organic wastes from the environment because of their high resistance to hydrophobic chemicals. Despite the many studies on the environmental and metabolic factors affecting cell surface hydrophobicity (CSH, the knowledge of this subject is still scanty and is in most cases limited to observing the impact of hydrophobicity on adhesion, aggregation or flocculation. The future of research seems to lie in finding a way to managing the microbial adhesion process, perhaps by steering cell hydrophobicity.

  15. Hydrophobicity of soil samples and soil size fractions

    Energy Technology Data Exchange (ETDEWEB)

    Lowen, H.A.; Dudas, M.J. [Albe