Ferroelectric bio-based materials with a high water content (z90 z 90 wt %) were not previously developed. Here, we develop hydrogels containing z 90 wt % water, amino acids (lysine and arginine) and oleic acid. The NH and CH groups of lysine hydrogen bond water, as shown by attenuated total reflectance-Fourier transform infrared spectroscopy, yielding electrically conductive solutions. Lysine also interacts with oleic acid, yielding hard materials with a lamellar crystal structure, as revealed by synchrotron small angle X-ray scattering. Polarized light microscopy and shear rheology show that aqueous mixtures of amino acids and oleic acid are birefringent gels. These gels have a columnar, hexagonal crystal structure with 54-85 wt % water, and a bi-continuous sponge crystal structure with 89 wt % water. They are piezoelectric, as demonstrated by cyclic voltammetry. Thus, they deform and undergo crystalline phase transitions when exposed to electric fields. The piezoelectric materials developed can find use in medical applications and clean energy harvesting.

Tetrahydrofuran (THF) is miscible in water due to hydrogen (H) bonding. Fatty acids and alcohols are miscible in THF and separate it from water, yielding bulk layers or emulsions. Separation is more effective with fatty alcohols and acids having intermediate solubility in THF-water mixtures. Fatty acids are more effective than fatty alcohols at separation, because carboxylic acid heads interact with THF more strongly than OH heads, as highlighted by activity coefficients estimated using COSMO RS (Conductor-like Screening Model for Realistic Solvents). These are lower with fatty acids than fatty alcohols. Infrared spectroscopy shows that THF disrupts H bonding of fatty alcohols, while enhancing H bonding of fatty acids. Moreover, activity coefficients are lower for acetic acid (representative of the heads) than alkanes (representative of the tails), indicating that THF interacts more strongly with the carboxylic heads than the tails. Therefore, we propose that fatty alcohols self-assemble into micelles with the heads pointing outwards and reside in the THF phase to prevent mixing with water. Small angle X ray scattering shows that oleic acid (unsaturated) self-assembles into micelles, similar to stearic acid (saturated), but is more disordered. While fatty acids interact with THF primarily through their heads, tails matter because they impede water-fatty acid interactions. Acetic acid does not induce separation. Fatty alcohols also self-assemble into micelles, which swell with water. Water H bonds the alcohol heads more strongly than THF, which instead interacts with the tails. With no or little water, longer tails enhance fatty alcohol solubility, yielding smaller clusters.

This study correlates the solution behaviour of an aqueous mixture to hydrogen bonding between its three components (water, liquid Pluronic L31 and either tetrahydrofuran, THF or dimethyl-sulfoxide, DMSO). Pluronic L31 is miscible in either THF, DMSO or water, but separates from ternary mixtures, at specific solvent to water ratios. Water species can either donate a single (SD) or two hydrogens (DD), and accept a single (SA) or two (DA) hydrogens, depending on the other components in the mixture. This is reflected in the OH stretch band, as probed using attenuated total reflectance-Fourier transform infrared spectroscopy. Pluronic L31 and THF both compete for hydrogen bonding with DD-DA, with up to 30% THF (v/v, relative to water), where separation occurs. Above 30% THF, Pluronic L31 and THF do not compete for the same water species and mix freely. Pluronic L31 separates from DMSO-water mixtures with 10-80% DMSO. Competition for similar water species explains separation up to 50% DMSO. Above 50% DMSO, we must also consider two-way interactions between all components. At low DMSO concentrations, DMSO mainly interacts with water trough the SO group, while methyl groups from DMSO can interact with Pluronic L31. At higher DMSO contents, the methyl groups of DMSO interact more markedly with water. The second derivative of the & nu;asCH3 peak displays a split with & LE; 50% DMSO, which disappears at higher DMSO percentages. The four peaks in the second derivative of the of the & nu;asCH3 peak correlate to the interactions between DMSO and the four water species.

Stearic acid separates tetrahydrofuran (THF) and water into either bulk phase or emulsions, above 30 % THF (relative to water, v/v). The oxygen on the THF ring interacts with either water or stearic acid through hydrogen (H) bonding, as probed using attenuated total reflectance - Fourier transform infrared spectroscopy. Upon mixing with water, the COC band of THF splits into four peaks (at 1020 cm(-1), 1040 cm(-1), 1050 cm(-1) and 1070 cm(-1)). These correspond to different THF species, i.e., THF molecules which coordinate in different ways with water. In THF-water mixtures containing >30 % THF (v/v), the dominant THF species yields a peak at 1050 cm- 1 & sdot;THF also interacts with stearic acid through H bonds, splitting the nu(COC) vibration into three peaks, at 1030 cm(-1), 1050 cm(-1) and 1065 cm(-1). Similar to THF-water mixtures, the peak at 1050 cm-1 is dominant in THF-stearic acid mixtures. Therefore, we propose that stearic acid induces separation by competing against water for interactions with the same THF species. Synchrotron X Ray diffraction in the small angle X ray scattering region shows that stearic acid self assembles into reverse micelles. Water likely partitions inside them, yielding either kinetically stable emulsions or rapidly separating into bulk layers. Upon separation, stearic acid resides in the THF-rich phase. This is because its hydrophobic tail prevents it from mixing with water, thereby rendering THF-stearic acid interactions more favorable. Acetic acid resembles the head of stearic acid and H bonds THF, without yielding separation. This demonstrates the importance of the stearic acid tail.

Sulfolane is a toxic pollutant freely miscible in pure water. However, above benchmark concentrations of sulfate or thiosulfate ions, it behaves as a light non-aqueous phase liquid and separates into either bulk phases or kinetically stable emulsions. Sulfolane droplets bear a negative electrostatic charge, as revealed by electrophoretic measurements. With high sulfate salt concentrations, the counterions screen the negative charge of sulfolane droplets. This promotes droplet coalescence and bulk phase separation, as well as droplet adhesion onto negatively charged mineral substrates such as clay and sand. NaCl does not separate sulfolane from water but favors its partitioning into toluene, as demonstrated by attenuated total reflectance-Fourier transform infrared spectroscopy. Water activity measurements show that sodium sulfate interacts with water more strongly than sulfolane, justifying its ability to displace sulfolane and induce its separation. Both sulfolane and sulfate ions interact with water through hydrogen (H) bonds. Water is comprised of water species that donate and accept a different number of H bonds, depending on other molecules in water. Sulfolane is an H bond acceptor. Therefore, it mainly interacts with double H bond donors that either do not accept H or accept only one H (double donorsingle acceptor, DD-SA). ATR-FTIR data indicate that sulfate ions compete with sulfolane more effectively than chlorides for interactions with DD-SA, thereby promoting better separation. Sulfolane phase separation can retard its migration in polluted aquifers. This study reveals the complex behaviour of sulfolane in water, with potential implications for sulfolane transport in groundwater.

Tetrahydrofuran (THF) and water are miscible and interact trough hydrogen (H) bonds. Span 80 (sorbitan ester) is soluble in THF, but not water. Nonetheless, Span 80 H bonds with water, as shown by attenuated total reflectance – Fourier transform infrared spectroscopy. In pure water, species are single (SD) or double (DD) donors, and single (SA) or double (DA) acceptors. In pure water, SD-SA and DD-DA are dominant and have similar abundance. Span 80 and THF alter the distribution of water species. When THF and Span 80 compete for the same water species, THF separation from water is most effective. Span 80 induces a marked shift of SD-SA to higher wavenumbers, which are close to DD-DA. This species intermediate between DD-DA and SD-SA is dominant, indicating that Span 80 mainly interacts with it. This same species is also dominant in THF-water mixtures containing 50–70% THF. Instead, DD-DA is dominant up to 40% THF, while DD-SA dominate at the highest THF percentages. Bottle tests show that Span 80 separates THF and water into bulk phases with 50–70% THF within 1 hr. In contrast, outside this THF range, emulsions are stable for more than 1 hr, as observed by either light scattering or optical microscopy. In mixtures with 50–70% THF, bulk phase separation occurs within 1 hr, because Span 80 competes with THF for the same water species. Separation is poorer outside of this THF range, where Span 80 and THF interact with different water species.

Rhamnolipids are bacterial amphiphiles. In addition to emulsifying hydrophobic solvents, they affect the phase behaviour of miscible solvents. In mixtures of toluene and water, rhamnolipids mediate the migration of metal ions (e.g., iron and copper) from the water to the toluene phase. Also, rhamnolipids phase separate the miscible solvent tetrahydrofuran (THF) from water, yielding emulsions even in the absence of toluene. This is because they compete with THF for hydrogen (H) bonding with similar water species. Water is an ensemble of species, including single donors (SD) or double (DD) donors, and single acceptors (SA) or double (DA) acceptors. In pure water, SD-SA and DD-DA have similar abundance and are dominant, as shown by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). With 50–200 g/L rhamnolipids, a water species intermediate between SD-SA and DD-DA is dominant, indicating that rhamnolipid-water interactions mainly occur through this species. This same species primarily interacts with THF, at 50–80% THF. At lower THF percentages, a similar (albeit not identical) species dominates, namely DD-DA, explaining separation. Emulsions are THF in water, as demonstrated by synchrotron mid-infrared spectro-microscopy and confocal microscopy using a hydrophobic dye. Synchrotron small angle X-ray scattering (SAXS) showed that rhamnolipids self- assemble into micelles, which contain THF. These findings have potential implications for miscible pollutant migration in groundwater, and their toxicity to rhamnolipid-secreting bacteria.

This study separates tetrahydrofuran (THF)-water mixtures containing varying THF percentages, using sorbitan esters (Spans) with different tail characteristics. We probe the separation mechanisms using attenuated total reflectance-Fourier transform infrared spectroscopy and small angle X ray scattering (SAXS). THF and water are miscible and interact through hydrogen bonds. Water splits the COC absorbance band of THF into a peak at ≈1,070 cm−1 (crystalline THF) and a dominant peak at ≈1,050 cm−1 (glassy THF), indicating disorder. Depending on the Span, separation occurs for mixtures containing up to 70% THF (v/v, relative to water). Spans with unsaturated tails separate the lowest THF percentages. Tail length and number of Span tails enhances ordering of THF, and the crystalline THF peak at ≈1,070 cm−1 dominates. Spans interact with THF through hydrogen bonds, as reflected in the splitting of the COC band of THF. Furthermore, C-H…O hydrogen bonds cause a blueshift in the νas(CH2) band of Spans with increasing THF. This effect is most significant in Span 40 and 60, indicating that they interact with THF more strongly than Span 20, Span 80 and Span 85. In contrast, they interact with water less strongly than Span 20, Span 80 and Span 85, as indicated by their flocculation at low THF percentages. Therefore, we propose that separation between THF and water occurs primarily through two mechanisms: 1) Span 20, Span 80 and Span 85 compete against THF for interactions with water through their hydrophilic head, and 2) Span 40 and Span 60 preferentially interact with THF through their tails. Nonetheless, water also interacts with the heads of Span 40 and Span 60, as indicated by SAXS. SAXS shows that in THF Spans self-assemble into micelles, which aggregate into either surface fractals or mass fractals. There are two persistence lengths because of the limited order in THF. Water orders self-assembled structures, likely by favoring the formation of micelles which host water in their interior. Therefore, we identify a single persistence length (≈25 Å), representative of the distance between the micelle centers.

Water is miscible with dimethylsulfoxide (DMSO), with which it interacts through hydrogen bonds (H -bonds). Glycerol monooleate (GMO, 53 g/L) demixes water and DMSO, yielding kinetically stable DMSO in water emulsions with up to X75 % DMSO (relative to water, v/v), as demonstrated by Fourier Transform Infrared (FTIR) spectromicroscopy, ultra small angle X-ray scattering (USAXS) and light scat-tering experiments, and optical microscopy. With > 75 % DMSO (relative to water) emulsions reverse and DMSO becomes the continuous phase (as shown by electrical conductivity measurements). The size of emulsified droplets decreases with increasing DMSO ratios (relative to water), as demonstrated by USAXS. Synchrotron X-ray Diffraction (XRD) measurements conducted in the small (SAXS) and wide angle (WAXS) regions show that the DMSO:water ratio affects GMO self-assembly. GMO (53 g/L) self -assembles into cubic crystal mesophases with 40 % DMSO (relative to water) and into disordered lamellar phases with 50 % DMSO. At even higher DMSO percentages, GMO self-assembles into reverse micelles, which contain water and are surrounded by DMSO (as shown by analyzing XRD data with the Steubner and Strey model). Although GMO mainly partitions in the DMSO rich phase, attenuated total reflectance (ATR)-FTIR measurements show that GMO interacts with water through H-bonds. Importantly, it increases the proportion of single H-bond donors (SD, which structure water the most) relative to double donors (DD, which structure water less). H-bonding between the hydrophilic head of GMO and initiates separation between DMSO and water, which would be H-bonded to one another in the absence of GMO. While this study focuses on DMSO, GMO also emulsifies water and tetrahydro-furan (THF), dimethylformamide (DMF) and dioxane. Our findings redefine which solvents can be emul-sified with water, and have potential implications for water treatment.(c) 2022 Elsevier B.V. All rights reserved.

Tetrahydrofuran (THF) is fully miscible in water, and it interacts with it via hydrogen (H) bonds. We discover that the fatty acid hydroxystearic acid (HSA) separates THF from water because it preferentially H-bonds water and increases the proportion of single H-bond donors (SD) relative to double H-bond donors (DD). This change in the coordination of water molecules from DD to SD leads to phase separation between THF and water. We previously established this separation mechanism using sugars and surfactants and other water miscible solvents. Here, we use attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) to prove that this mechanism is also responsible for THF–water separation using HSA, thereby demonstrating the universality of the proposed separation mechanism. Using synchrotron small-angle x-ray scattering, we show how HSA self-assembles into reverse micelles in THF–water mixtures and determine their persistence length and periodicity using a modified Landau model. Reverse micelles host water in their interior and swell upon increasing the water content, as shown by light scattering. They then turn into droplets detectable using optical or confocal microscopy. When THF–water emulsions separate, they yield water-rich and THF-rich free phases. ATR-FTIR reveals that the top phase of THF–water mixtures separated by HSA is THF-rich. Moreover, when Cu2+ ions are in solution, HSA causes their migration into the THF-rich phase, enabling the simultaneous separation of THF and Cu2+ cations from water. This study demonstrates the potential for engineering the water structure to aid in the separation of water-miscible solvents from water with important implications for water treatment.

Sodium lauroyl lactylate (SLL) is soluble in water and insoluble in organic solvents, while glycerol monooleated (GMO) is soluble in organic solvents and insoluble in water. These amphiphiles separate miscible solvents (e.g., water and either dimethylsulfoxide, DMSO, dimethylformamide, DMF, acetonitrile, AN, or tehtrahydrofuran, THF). Separation segregates water and the organic solvents into either microdomains (emulsified droplets) or free phases. With mixtures containing 3:7-7:3 DMF:water ratios (v/v), SLL kinetically stabilizes DMF-water emulsions for over a week (longer times were not investigated). Emulsions are DMF in water with DMF:water ratios <= 2:3, and water in DMF for DMF:water ratios >= 1:1. Optical microscopy and SEM illustrate emulsification, and confocal microscopy qualitatively shows segregation between DMF (dyed with fluorescein) and water (which appears dark in confocal images). Water droplets in DMF are kinetically stable because they are surrounded by self-assembled SLL cubic mesophases, either gyroid or primitive, depending on the SLL and DMF concentrations (as demonstrated by x-ray diffraction, XRD). SLL also stabilizes DMSO-water emulsions (for over a week), thereby segregating the two solvents with similar mechanisms. DMSO-water separation is quantitatively demonstrated by mid-infrared (mid-IR) spectromicroscopy. Separation between AN and water occurs for AN-water mixtures in which SLL has intermediate solubility, i.e., with 3:2 and 4:1 AN:water ratios (v/v). In this range, SLL yields emulsions which destabilize overnight, separating into AN-rich and water-rich phases, as demonstrated using nuclear magnetic resonance (NMR). In water, SLL self-assembles into primitive cubic liquid mesophases and it affects hydrogen bonding (H-bonding) of water, as shown by deconvolving the H-bond peak into peaks representative of different water clusters, comprised of water molecules donating and accepting a different number of H-bonds. In water, SLL induces a blue shift of the hydrogen bonding (H-bonding) of absorbance peaks for double (DD) and single (SD) H-bond donors, indicating that it strengthens H-bonding. Importantly, it increases the ratio between the amplitude A of SD relative to DD, and SD are most effective at structuring water. As a result, SLL would inhibit interactions between organic solvents and water, initiating separation. Similar to SLL, GMO is known for its ability to form cubic mesophases. GMO stabilizes emulsions of water miscible solvents (THF, DMSO and DMF) and water. This result indicates that selected amphiphiles selfassembled into cubic mesophases can emulsify miscible solvents.

This study uses sugars (dextrose, sucrose, ribose, fructose and mannose) and sugar alcohols (maltitol, erythritol, sorbitol, xylitol) to separate water from tetrahydrofuran (THF) and acetonitrile (AN). Bottle tests and nuclear magnetic resonance (NMR) show that above 0.25 M all sugars and sugar alcohols effectively separate water from either THF or AN. At 0.5 M concentrations, maltitol and sucrose yield a non-negligible interfacial tension between AN and water, while the interfacial tension is negligible with all other compounds. This indicates that while all compounds have similar separation effectiveness above a benchmark concentration, maltitol and sucrose (which are dimers) have a stronger effect on water structure compared to the other compounds tested (which are monomers). Attenuated Total Reflectance - Fourier Transform Infrared spectroscopy (ATR-FTIR) was used to explain solvent separation, based on the effect of sugars on hydrogen bonding (H-bonding) and on the nitrile band. The H-bonding peak was deconvolved into peaks representative of different water clusters, comprised of water molecules donating and accepting a different number of H-bonds. Principal component analysis (PCA) shows that single H-bond donors (SD) (at approximately 3200 cm(-1)) and double H-bond donor (DD) (at approximately 3400 cm(-1)) are most affected by maltitol and sucrose. All sugars tested induce a blue shift of the H-bonding of absorbance peaks for DD and SD, in either water or in mixtures of water-AN and waterTHF. This indicates that they strengthen H-bonding in these clusters. The effect of all sugars is comparable when concentrations are expressed as OH equivalents. Sugars increase the ratio between the amplitude A of SD relative to DD, and SD are most effective at structuring water. The difference between the ratio A(SD)/A(DD) after and before sugar addition is lowest in water (approximate to 0.9), followed by THF-water mixtures (approximate to 1.1) and AN-water mixtures (approximate to 1.2). This indicates that solvents enhance the effect of sugars on H bonding. This is likely because sugars are not soluble in either THF or AN, which therefore excludes them and promotes their interactions with water. In turn, water-sugar H-bonding weakens interactions between AN-water or THF-water, leading to solvent separation. The analysis of the nitrile band shows that sugars and sugar alcohols increase the relative amount of free nitrile, which is correlated to weaker interactions between AN and water. Maltitol and sucrose display approximately two times the relative amount of free nitrile compared to dextrose and erythritol. Our study confirms that sugars and sugar alcohols weaken solvent-water interactions, and reveals that they separate solvents by increasing the proportion of SD relative to DD.

Co-contamination by organic solvents (e.g., toluene and tetrahydrofuran) and metal ions (e.g., Cu 2+ ) is common in industrial wastewater and in industrial sites. This manuscript describes the separation of THF from water in the absence of copper ions, as well as the treatment of water co-polluted with either THF and copper, or toluene and copper. Tetrahydrofuran (THF) and water are freely miscible in the absence of lauric acid. Lauric acid separates the two solvents, as demonstrated by proton nuclear magnetic resonance ( 1 H NMR) and Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR). The purity of the water phase separated from 3:7 (v/v) THF:water mixtures using 1 M lauric acid is ≈87%v/v. Synchrotron small angle X-Ray scattering (SAXS) indicates that lauric acid forms reverse micelles in THF, which swell in the presence of water (to host water in their interior) and ultimately lead to two free phases: 1) THF-rich and 2) water-rich. Deprotonated lauric acid (laurate ions) also induces the migration of Cu 2+ ions in either THF (following separation from water) or in toluene (immiscible in water), enabling their removal from water. Laurate ions and copper ions likely interact through physical interactions (e.g., electrostatic interactions) rather than chemical bonds, as shown by ATR-FTIR. Inductively coupled plasma—optical emission spectrometry (ICP-OES) demonstrates up to 60% removal of Cu 2+ ions from water co-polluted by CuSO 4 or CuCl 2 and toluene. While lauric acid emulsifies water and toluene in the absence of copper ions, copper salts destabilize emulsions. This is beneficial, to avoid that copper ions are re-entrained in the water phase alongside with toluene, following their migration in the toluene phase. The effect of copper ions on emulsion stability is explained based on the decreased interfacial activity and compressional rigidity of interfacial films, probed using a Langmuir trough. In wastewater treatment, lauric acid (a powder) can be mixed directly in the polluted water. In the context of groundwater remediation, lauric acid can be solubilized in canola oil to enable its injection to treat aquifers co-polluted by organic solvents and Cu 2+ . In this application, injectable filters obtained by injecting cationic hydroxyethylcellulose (HEC +) would impede the flow of toluene and copper ions partitioned in it, protecting downstream receptors. Co-contaminants can be subsequently extracted upstream of the filters (using pumping wells), to enable their simultaneous removal from aquifers.

Rapid swelling, high amylopectin starches including Thermally Inhibited (TI), Chemically Modified (CM), and Granular Cold- Swelling (GCS) were assessed for their supporting matrix forming potential and properties. Starches displayed identical calorimetric profiles with no endothermic events, and completely amorphous structure as judged by powder X-ray diffraction. However, they each provided different textural attributes. The starches were combined with pea protein isolate at a total concentration of 47%w/w (d.b.) to create a proteinacious supporting matrix. The starch protein matrix was then tested in a non-cold-set dough state as well as in a cold-set state after storage for 24h at 5oC. In the non-cold-set state, hardness increased with the addition of protein. CM was the softest dough and was difficult to work with, while TI and GCS were harder, with TI having the greatest resilience. Once cold-set, the textural properties changed, and GCS was not able to form a solid structure, instead remaining a viscoelastic dough. The hardness and storage modulus (G') of TI and CM displayed a negative correlation with the addition of protein due to matrix disruption. However, the combination of TI starch and pea protein at a ratio of 70% starch and 30% protein in the dry fraction displayed a synergistic effect, with increased resilience, chewiness, and ductility. FTIR of TI starch and protein at the same 70:30 ratio provided further evidence for the existence of an interaction between pea protein and TI starch. The results support the use of TI rapid swelling starch and pea protein isolate as a supporting matrix for application in meat analogue systems.

Flexible and hydrophobic biobased films were obtained using zein esterified with methanol and para-toluene (p-toluene) sulfonic acid, cutin from tomato peels and ethanol. Esterification was confirmed by proton nuclear magnetic resonance and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Non-modified zein films were brittle and hydrophilic. ATR-FTIR demonstrated that zein esterification increased zein hydrophobicity. Without cutin, esterified zein films were hydrophobic but brittle. Addition of cutin yielded films that were flexible and hydrophobic, as demonstrated by contact angle measurements. Principal component analysis (PCA) of ATR-FTIR data showed that intensities at 3195 cm(-1) and 3490 cm(-1) were correlated to the relative hydrophobicity of zein films. PCA also showed that films of esterified zein and cutin were more hydrophobic than their counterparts (non-modified zein without cutin). Optical and scanning electron microscopy demonstrated that esterified zein was compatible with cutin and yielded cohesive films, which did not fracture upon bending.

Fracking is an enhanced oil recovery technology, which uses viscoelastic fluids (fracking fluids) to fracture oil reservoirs and to transport sand within the fractures, to prop them open. This technology enables oil recovery from scarcely permeable formations. Fractured formations release saline water over time. This saline water (called "produced water") is discarded rather than used to produce fracking fluids because it can decrease fracking fluid viscosity. Nonetheless, it would be advantageous to use produced water to reduce freshwater consumption and wastewater production. Our study analyzes the effect of chloride salts (CaCl2, MgCl2, and Fe(III)Cl) and of sulfate salts (MgSO4 and FeSO4) at different concentrations (0.05-1 M) on the viscosity of aqueous guar solutions. All chloride salts tested increase the viscosity of guar solutions in the concentration range analyzed and promote the formation of small guar aggregates. At 0.05 M concentrations, MgSO4 has effects similar to chloride salts. In contrast, 1 M MgSO4 decreases the viscosity of guar solutions. FeSO4 also decreases the viscosity of aqueous guar solutions, at either 0.05 or 1 M concentrations. The decrease in viscosity of guar solutions is attributed to large guar aggregate formation (as opposed to a cohesive network). Sodium cocoyl glutamate (SCG) increases the viscosity of non-cross-linked guar solutions and the shear viscoelastic moduli of guar solutions cross-linked with sodium tetraborate. Specifically, SCG restores the viscosity of guar solutions with MgSO4 and increases it above values measured in deionized (DI) water in the presence of MgCl2. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy shows that hydrogen bonding was more significant in guar + SCG + 0.7 M MgCl2 samples than in guar + SCG + 0.7 M MgSO4, indicating that the formation of a hydrogen-bonded network was correlated to high viscosity. ATR-FTIR also indicates that MgSO4 weakened hydrogen bonding of water clusters, whereas SCG restored it, enabling guar hydration even in the presence of MgSO4. Our study highlights which salts are most problematic (e.g., FeSO4) and proposes a potential additive (SCG) to enhance the viscosity of guar in the presence of selected salts (e.g., magnesium salts) by promoting hydrogen bonding.

High groundwater concentrations of heavy metals such as copper are toxic to humans. Attenuated total reflectance - Fourier transform infrared spectroscopy (ATR-FTIR) demonstrated that the environmentally benign surfactant sodium lauryl lactylate (SLL) formed bidentate complexes with copper ions. CuSO4 increased the surface tension and the compressional rigidity of SLL films at air-water interfaces, providing additional evidence of SLL-Cu interactions. Here, we harness for the first time the formation of Cu-SLL complexes to achieve the three following objectives. First, SLL enabled the facile detection of copper in water samples, by enhancing the color of copper solutions (10-3 M copper concentrations could be detected with the naked eye). Second, SLL promoted the desorption of copper from model polluted soils. Therefore, SLL can be useful for surfactant flushing applications, in which surfactants are used to enhance the remediation of polluted aquifers through pump and treat. Third, SLL enhanced the treatment of water polluted with copper ions. Specifically, SLL favored the partitioning of Cu2+ into canola oil, purifying water. Therefore, canola oil could be used as liquid sorbent for the treatment of groundwater in SLL-enhanced pump and treat, in which polluted groundwater would be pumped and then treated at the surface. The safety of the proposed treatment can be improved by injecting fluids obtained with the biopolymer sodium alginate (Na-alginate) around the treated area. Na-alginate fluids (at 0.5 wt%) had low viscoelastic moduli before contact with Cu2+ (facilitating their injection) and gelled when intercepting Cu2+ ions (to allow their confinement inside the boundaries of the treated area).

Zein and laccase were used to remove naphthalene from water using two approaches. The first approach sorbed naphthalene onto laccase-containing solid zein sorbents coagulated with either CaCl2 at pH = 13 or with Fe2Cl3 at pH = 10. These sorbents were never used before for this purpose. Fluorescence spectroscopy showed that laccase degraded naphthalene in water at neutral pH. Laccase activity was pH-dependent: laccase retained its activity after exposure to pH values as high as 10, and had maximum activity at pH = 5.5. Laccase immobilized in zein sorbents coagulated with Fe2Cl3 at pH = 10 had a relative activity of approximately 8%, whereas activity significantly decreased in zein sorbents coagulated with CaCl2 at pH = 13. Attenuated total reflection Fourier-Transform Infra-Red (ATR-FTIR) spectroscopy showed naphtalene sorption onto zein sorbents through hydrophobic interactions and CH/π bonding between naphthalene (the π base) and the aliphatic groups (hydrogen donors) of non-polar residues of zein. Gas Chromatography Mass Spectroscopy (GCMS) demonstrated naphthalene removal from water. The sorption capacity of zein sorbents was ≈ 14 mg/g at 21⁰C, and followed first-order kinetics with a rate constant of 0.0066 min−1. The second approach used zein and laccase to stabilize air bubbles in water, for air sparging applications. Air sparging injects air in contaminated aquifers to strip volatile contaminants from groundwater. Small, stable air bubbles with large surface area enhance contaminant removal. Previous studies used surfactants to stabilize air bubbles. However, they did not use foaming agents that were also able to adsorb and degrade contaminants. In this study, we produce "reactors on an air bubble" able to strip and degrade naphthalene in groundwater. Interfacial tension measurements showed that laccase and zein adsorbed at the air-water interface at either acidic or alkaline pH. At acidic pH, the compression isotherms of zein-laccase films at the air-water interface differed from those of the individual components, suggesting zein-laccase co-adsorption. At alkaline pH, iron promoted co-adsorption of zein-laccase at the air-water interface, likely by modulating their electrostatic interactions. Foams were stable at alkaline, with either zein alone or zein-laccase complexes, and iron enhanced foam stability. These results indicate that zein and laccase can facilitate the remediation of naphthalene by promoting air bubble stability and naphthalene sorption at the air-water interface, as well as its enzymatic degradation.

Zein-based materials were produced by dissolving zein water at pH 13, and subsequently congealing it with CaCl2. Biocarbon particles were produced with miscanthus biomass by pyrolization at 650 °C (M-L) and at 900 °C (M-H), followed by ball-milling. Increasing the pyrolization temperature caused the disappearance of functional groups on the particle surface and increased their hydrophobicity of the particles (as shown through Attenuated Total Reflection- Fourier Transform Infrared Spectroscopy, ATR-FTIR and by the preferential partitioning on the particles in toluene rather than water). Therefore, hydrophobic interactions were likely stronger between zein and M-H particles, than between zein and M-L particles. Measurements conducted using a zeta sizer showed that aggregates of zein and M-L particles were > 1 µm, and aggregates of zein and M-H particles were < 1 µm. M-H particles increased the shear viscous (G″) and elastic (G″) moduli of zein, and rendered the material elastic (G′ ≅ 6.6 × 104 Pa > G″ ≅ 5.7 × 104 Pa with M-H and G′ ≅ 4.3 × 104 Pa and G″ ≅ 4.6 × 104 Pa without zein). M-H particles also increased the tensile strength of zein materials, potentially improving their usefulness as bioplastics. M-L particles increased the viscoelastic moduli of zein (G′ ≅ 6.7 × 104 Pa and G″ ≅ 7.3 × 104 Pa), but did not render the material elastic (i.e. G′ was not greater than G″). Moreover, M-L particles stiffened zein at small elongational deformations, but rendered it brittle at larger deformations. M-H particles greatly reduced the permeability of zein barriers injected in sandy media, which can be for instance used to prevent the migration of subsurface contaminants. Flow reduction was 90% with zein and M-H, whereas it was 64% with zein only and 68% with zein and M-L particles and zein.

Oxodegradable agricultural films must have predictable lifetimes if benefits associated with their use are to be maximized. This paper presents results examining the change in degradation of oxodegradable films upon exposure to a commonly used insecticide, Pyrinex 480. Pieces of oxodegradable agricultural film, both untreated and treated with different doses of this pesticide in the range of 3.0-10.6 +/- 0.5 mg/m(2) of film, were placed in a field environment, gravity ovens at 60, 70 and 80 degrees C, and an accelerated aging environment that included elevated temperature and exposure to UV light. Degradation of the films was inferred from carbonyl index values calculated using measured infrared absorbance spectra of films collected as a function of exposure time. A delay in oxidation was observed in films treated with Pyrinex 480 relative to untreated films. This delay was most pronounced in environments that included exposure to light. Measurement of the UV absorbance of the pesticide and measurement of its ability to act as a chain-breaking donor or acceptor suggest that Pyrinex 480 achieves its effect on degradation by acting as a UV screener, which has important implications for the use of this type of film where pesticide exposure may be encountered. (C) 2016 Elsevier Ltd. All rights reserved.