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Reverse osmosis (RO) membranes have been widely used in seawater desalination and drinking water preparation due to their outstanding ability to retain low valence salt ions and large organic molecules. Small neutral molecules (SNMs) are widely present in water, typically represented by boric acid in seawater and urea in wastewater. Reducing SNMs to meet drinking water standards is a new challenge for RO membranes. In this study, we developed a thin-film composite RO membrane tailored for seawater desalination, demonstrating exceptional selectivity against SNMs and heightened permeability. Specifically, a nonionic surfactant, flexible polyisobutylene succinimide (PIBSI), was added into the organic phase to react with trimesoyl chloride (TMC). The results showed that the new product, PIBSI–TMC, effectively exhibited the dual function of surfactant and co-monomer changed the physicochemical structure of PA formation during the interfacial polymerization process based on the detailed characterization. PIBSI integrated into the PA matrix significantly enhanced the hydrophobicity of the membrane surface and increased the specific surface area. Simultaneously, the pore size within the layer was reduced, and defects on the RO membrane surface were filled. The objectives were achieved by enhancing the size exclusion mechanisms effect, reducing SNMs diffusion rate, and ultimately improving selectivity. Experimental results demonstrated that the novel membrane achieved excellent desalination performance and a maximum boron removal efficiency of up to 90.40% in simulated seawater (32000 ppm NaCl, 5 ppm boron) compared to virgin membrane. The produced freshwater meets drinking water standards in various regions. Additionally, it exhibited higher flux (48.0 L m−2 h−1, 55.0 bar, approximately 26.4% permeate flux decline) compared to similar membranes. In addition, the rejection of SNMs in wastewater represented by urea was also effective. Therefore, it is favorable for application in resource recovery and pollutant removal. In conclusion, this novel RO membrane holds broad prospects for applications in seawater desalination and potable water production. [ABSTRACT FROM AUTHOR]

Aqueous solutions of nonionic surfactants behave differently than those of ionic surfactants. Micellar properties and structural characterization of Polysorbate 80 (commonly known as Tween 80) were investigated in the presence of different additives at different temperatures (303–323 K) by using cloud point (CP), densitometry, and viscometry techniques. Nonionic surfactant shows the optimum effect when used near their CP, as the presence of additives strongly influences them. The compounds or additives that break the structure of water will increase the CP, while those that help to build the water structure show a decrease in the CP. Adding ester, urea, and carbohydrates decreases the CP of Polysorbate 80, while alcohol and thiourea show the opposite trend. Density and viscosity measurements of Polysorbate 80 in the presence of monovalent salts (NaX, X = Cl–, Br–, , and salicylate) confirmed the change in molecular structure. [ABSTRACT FROM AUTHOR]

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The Museum of Sun Yat-sen University houses a collection of antique glass slides dating back to the 1940s. These historical artifacts not only serve as a record of the past but also bring history to life. During extended storage, the emulsion layer on glass slides may harden and become brittle, leading to cracking and buckling. This study suggests a method to enhance the physical property of the emulsion layer by using a combination of nonionic surfactant isomeric alcohol ethoxylates eight (TO-8) and waterborne epoxy resin (WER). We investigated the microscopic action mechanism of the two on the emulsion layer of glass slides using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), water contact angles, and other techniques. Our study revealed that TO-8 can significantly eliminate the spherulitic crystal structure of the emulsion layer, as well as improve its softness and hydrophilicity. The addition of the WER ensures that the cracking and warping of the emulsion layer film is fully corrected, resulting in a flat surface. Additionally, the size of the emulsion layer film remains stable even after wetting. The WER has minimal impact on the image information of glass slides. The emulsion layer of the glass slides, restored using the softening protection solutions developed in this study, showed almost full recovery of image information. This research holds significant theoretical and practical value for repairing cracked and warped emulsion layers on glass slides. [ABSTRACT FROM AUTHOR]

Dynamic light scattering has been employed to investigate aqueous Pluronic P123 solutions at different temperatures and in the presence of different solvents and quercetin additives. Significant changes have been revealed in the average particle size and polydispersity index depending on the conditions. The effect of temperature on micellization of the block copolymer in aqueous solutions has been studied in a range T = 15–45°C, which is most often considered when using P123 in the sol–gel synthesis of silica. The most pronounced effect of temperature on the micellization of the studied surfactant has been observed at T = 15–20°C. In this temperature range, the scattered light intensity distribution over particle sizes has a polymodal character, which indicates the presence of macromolecules, micelles, and their aggregates in the system. A further increase in temperature up to 45°C causes no significant changes in the particle size. In aqueous solutions, micelles with a narrow size distribution (minimum polydispersity index) are formed within temperature ranges of 21–25 and 35–40°C. Substantial effects have been found when adding alkanols and polyphenolic substances as solubilizers capable of influencing the structure of micelles both in their bulk and on the surface of polar moieties of the surfactant. It has been shown that, in the presence of butanol-1, micelles are stabilized at temperatures of 15–20°C. At T > 30°C, the structure of micelles is transformed. As the fraction of butanol-1 in the solution increases, its influence is manifested at lower temperatures. It has been noted that ethanol has a destructive effect on micelles. Additives of quercetin exhibit an opposite effect of micelle stabilization, which leads to the formation of a homogeneous surfactant structure. It has been shown that, by varying solvent composition, the flavonoid–micelle binding can be controlled due to changes in the solvation. The greatest influence of quercetin on the structure formation of P123 has been observed at a solvent composition corresponding to ethanol-to-block copolymer molar ratio of n(EtOH) : n(P123) = 80 : 1. [ABSTRACT FROM AUTHOR]

Water and several chemicals, including dyestuffs, surfactants, acids, and salts, are required during textile dyeing processes. Surfactants are harmful to the aquatic environment and induce several negative biological effects in exposed biota. In this context, the present study aimed to assess acute effects of five surfactants, comprising anionic and nonionic classes, and other auxiliary products used in fiber dyeing processes to aquatic organisms Vibrio fischeri (bacteria) and Daphnia similis (cladocerans). The toxicities of binary surfactant mixtures containing the anionic surfactant dodecylbenzene sulfonate + nonionic fatty alcohol ethoxylate and dodecylbenzene sulfonate + nonionic alkylene oxide were also evaluated. Nonionic surfactants were more toxic than anionic compounds for both organisms. Acute nonionic toxicity ranged from 1.3 mg/L (fatty alcohol ethoxylate surfactant) to 2.6 mg/L (ethoxylate surfactant) for V. fischeri and from 1.9 mg/L (alkylene oxide surfactant) to 12.5 mg/L (alkyl aryl ethoxylated and aromatic sulfonate surfactant) for D. similis, while the anionic dodecylbenzene sulfonate EC50s were determined as 66.2 mg/L and 19.7 mg/L, respectively. Both mixtures were very toxic for the exposed organisms: the EC50 average in the anionic + fatty alcohol ethoxylate mixture was of 1.0 mg/L ± 0.11 for V. fischeri and 4.09 mg/L ± 0.69 for D. similis. While the anionic + alkylene oxide mixture, EC50 of 3.34 mg/L for D. similis and 3.60 mg/L for V. fischeri. These toxicity data suggested that the concentration addition was the best model to explain the action that is more likely to occur for mixture for the dodecylbenzene sulfonate and alkylene oxide mixtures in both organisms. Our findings also suggest that textile wastewater surfactants may interact and produce different responses in aquatic organisms, such as synergism and antagonism. Ecotoxicological assays provide relevant information concerning hazardous pollutants, which may then be adequately treated and suitably managed to reduce toxic loads, associated to suitable management plans. [ABSTRACT FROM AUTHOR]

The purpose of the current work is to explore the interactions between antidepressant drug amitriptyline hydrochloride (AMT, an amphiphilic) and Triton-165 (TX-165, a nonionic surfactant) by applying surface tension, and UV–visible spectroscopy methods. In diverse solvents (aqueous system/50 mmol kg−1 NaCl/500 mmol kg−1 urea), experimental results using the surface tension technique revealed non-ideal behavior along with attractive/synergistic interactions at interface among the AMT drug and TX-165 mixed systems. As contrasted with aqueous system, NaCl media boosted the interfacial properties, resulting in increased synergism/attractive interaction between ingredients (AMT and TX-165), while urea media had the opposite effect. Numerous interfacial parameters such as surface excess concentration (Γmax), surfactant composition at mixed monolayer ( X 1 σ ), interaction parameters (βσ) activity coefficient [f1σ (TX-165) and f2σ (AMT)], and minimum area per molecule ( A min ) were assessed and illustrated in detail. Interaction parameters (βσ) at surface were attained negative in each case revealing the attractive/synergism among the constituents. It was found that the Gibbs energy of adsorption ( Δ G ads ∘) throughout all utilized solvent was negative, which indicates spontaneity in the adsorption phenomena. AMT + TX-165 mixtures show synergistic or attractive interactions and non-ideal mixing behaviors at surface depending on mixture composition. In addition, UV–visible analysis detected peak shifts and a surge in absorbance during the interaction of TX-165 with TX-165. It was suggested in the current study that TX-165 surfactant could be used for effective drug delivery of antidepressants. [ABSTRACT FROM AUTHOR]

A surfactant with biodegradability and amphiphilicity was prepared from cellulose nanocrystals by grafting fatty acids. The structure of the modified cellulose nanocrystals was investigated by infrared spectroscopy, XRD, particle size detection and scanning electron microscopy. The changes in surface tension of the modified cellulose nanocrystals under different salt ion concentrations and pH were tested, and the molecular model of the modified cellulose nanocrystals was constructed. The optimum reaction conditions for the grafting of different fatty acid groups were determined by the degree of substitution. Infrared characterization and X-ray diffraction analysis showed that the reactants were successfully esterified and chemically modified. The particle detection shows that the average particle size of the modified cellulose nanocrystals is slightly increased, but it is still at the nanometer level and still has large specific surface area. The surface tension of the surfactant in the aqueous phase will decrease by changing the salt concentration and pH of the test environment, while the range is not large. Therefore, using trifluoroacetic anhydride as co-reactant, long-chain fatty acids can be grafted onto cellulose nanocrystals to form hydrophobic modified cellulose nanocrystals. The modified cellulose nanocrystals have little change in average particle size and have hydrophilic and lipophilic properties and are nonionic surfactants, which can be used as emulsifier for emulsion preparation. It is found that the modified cellulose nanocrystals have good salt resistance and acid and alkali resistance by testing the changes in surface tension under different environments. [ABSTRACT FROM AUTHOR]

Chemical flooding is a beneficial approach to enhance oil recovery from hydrocarbon reservoirs. Surfactant flooding due to the capability of oil/water interfacial tension (IFT) reduction is a very well-known approach. However, the adsorption of surfactants on the rocks' surface makes this approach less feasible and too complex to model. This study attempts to analyze the adsorption behavior of saponin on sandstone rocks. Saponin is a natural surfactant found in more than 500 plant species. The adsorption behavior of this surfactant follows the Langmuir isotherm model with a negligible error of 0.98%. Experimental studies revealed that saponin adsorption capacity decreases when the temperature rises, but the behavior still follows the Langmuir isotherm model in elevated temperatures. Furthermore, the effect of particle size on adsorption behavior was also investigated experimentally, whereas smaller particles were found to provide higher adsorption capacities for saponin molecules. In the current research, a model based on thermodynamic equations has been constructed capable of predicting the adsorption behavior of saponin on sandstone rocks in extended conditions. Experimental data were also employed to verify the model performance. Moreover, the core plug and batch adsorption capacities were compared to each other, which showed that the core adsorption capacity is much lower than the batch condition. Comparing results achieved in this study with other natural surfactants, it is explicit that saponin induces a ten times lower critical micelles concentration (CMC) and adsorption tendency on sandstone rocks, which can make saponin a superior natural surfactant with invaluable applications in chemical EOR jobs. [ABSTRACT FROM AUTHOR]

Alkylphenolpolyethoxylates whose bioresistant metabolites (alkylphenols, short-chain alkylphenolpolyethoxylates and alkylphenoxycarboxylic acids) are compounds with hormonal activity that pose a serious threat to living organisms are among the main types of nonionic surfactants widely used in industry and everyday life. Advanced oxidation processes (AOPs)—in particular, photocatalytic processes—are capable of effectively removing such impurities from an aqueous medium. However, photocatalytic oxidation of some synthetic surfactants with oxygen until their complete mineralization proceeds slowly. The combined use of a photocatalyst and oxidizing agents that are stronger than oxygen contributes to an increase in the degree of mineralization of organic impurities and a decrease in the reaction time compared to those achieved with separate treatment by both methods, which gives rise to the lower cost of water purification and improves the environmental friendliness of the combined process. The photocatalytic processes of degradation of nonionic surfactant octylphenol ethoxylate (Triton X-100) in an aqueous medium by ozone (O3), by ozone and UV radiation jointly (O3/UV), and by ozone and atmospheric oxygen in a TiO2 Degussa P-25 suspension (O3/TiO2/UV and O2/TiO2/UV) under UV irradiation with a DB-15 low-pressure mercury quartz lamp (λ = 254 nm) have been studied. The parameters of photocatalytic ozonation have been determined to ensure the nearly complete destruction of Triton X-100 (97% according to total organic carbon). The advantages of photocatalytic ozonation of a Triton X-100 solution in comparison with ozonation, O3/UV treatment, and photocatalytic oxidation with air oxygen are demonstrated. [ABSTRACT FROM AUTHOR]

Reactive dyes of three primary colours used for exhaustion dyeing of cotton fabric in conventional water dyeing system and APG-based reverse micelle dyeing system, with D5 and alkane solvents as dyeing medium, were investigated. Calibration curves of both systems were established. Absorbance and dye concentration were found to be directly correlated with each other. The curves exhibited high linearity with R2 above 0.99, validating their suitability for subsequent SERF measurement. The values of substantivity factor (S), exhaustion factor (E), rate of fixation (R) and fixation factor (F) were measured and calculated in percentage. The results revealed that APG reverse micellar dyeing system obtains higher S and E, but lower R and F values than the conventional water dyeing system, verifying excellent final dye exhaustion and good leveling properties of the APG reverse micellar dyeing system when compared with the conventional aqueous dyeing system. The use of D5 and alkane solvents as dyeing medium causes no significant effect on the establishment of SERF profile in APG reverse micellar dyeing system. [ABSTRACT FROM AUTHOR]

New nonionic surfactant LMAEO-3 has been synthesized and characterized using Fourier-transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (1HNMR). An analysis of the critical micelle concentration (CMC) ratio was conducted, which reached 11 × 10−5 M. This surfactant protected aluminum from reacting with 1.0 M hydrochloric acid. In the process of checking its efficiency, electrochemical impedance spectroscopy (EIS) was employed. The double layer's resistance and capacity increased significantly due to the experiment, and it had a percentage of efficiency of 82.8%. Further, the potentiodynamic polarization study demonstrated that LMAEO-3 is a mixed-type inhibitor that inhibits current density as surfactant concentrations increase, making sense from electron frequency modulation (EFM). Observe how Langmuir's theory applies to the adsorption of this surfactant on aluminum. These results were in agreement with the theoretical results derived from Materials Studio and atomic force microscopy (AFM) testing results, which demonstrated the smoothness of the aluminum surface when only exposed to hydrochloric acid in the presence of a surfactant. [ABSTRACT FROM AUTHOR]

A new synthesis procedure is presented, for the first time, to prepare mesoporous silica nanosphere by using mixed surfactants of nonionic, biocompatible alkylpolyglucoside and cationic cetyltrimethylammonium bromide (CTAB). This method aimed to decrease the CTAB mole ratio due to its high toxicity while keeping a well-defined morphology and structure of the particles. The obtained materials were tuned by changing the template and its concentrations. The structural and morphological properties were investigated by transmission electron microscopy, nitrogen adsorption and small-angle X-ray diffraction. Highlights: Sol–gel synthesis technique was used to produce the amorphous mesoporous silica. Present research work deals with synthesis with APG surfactant and cationic surfactant both. Without small content of CTAB, the APG surfactant cannot react with itself. The objective is the possible reduction of cationic surfactant and replace it by APG with keeping the same spherical morphology. [ABSTRACT FROM AUTHOR]

The inhibition effect of the synthetic nonionic surfactants (NIS) on the dissolution of carbon steel in 0.5 M H2SO4 solution has been demonstrated using different techniques. NIS compounds were characterized by IR and 1H NMR spectra. Corrosion parameters resulting from the techniques used confirm that inhibiting power of NIS compounds was increased with increasing NIS compounds, lowering temperature and surface properties e.g., surface tension, interfacial tension and critical micelles concentrations. Low values of surface properties increase the adhesive strength between NIS compounds and the carbon steel surface, which improves the adsorption process. Adsorption of NIS compounds is spontaneous and obeys Temkin's isotherm. The high inhibition efficiency of NIS compounds depends on the presence of more electron donor atoms, which increases the electron density at the adsorption center. Some thermodynamic functions have been identified and interpreted. [ABSTRACT FROM AUTHOR]

The SAPO-34 catalysts were successfully synthesized with different amounts of a cheap and green nonionic surfactant (Triton X-100) as a mesoporogen additive and MOR/TEAOH as microporous mixed templates. The prepared samples were characterized and tested in the methanol to olefins (MTO) reaction under the industrial feed composition of 72 wt% methanol in water. The results revealed that the surfactant concentration affects the acidity, particle size, and textural properties which results in different catalytic performances. The sample prepared with the surfactant molar ratio of 0.02 exhibits a 12% improvement in the light olefins selectivity (90%) as well as the longer catalyst lifetime (more than 330 min) compared to the parent one (79.3% selectivity and 260 min lifetime). This could be attributed to the high crystallinity, smaller crystallite size, proper lower acidity, higher surface area, and the facilitation of reactants and product transportation through mesoporosity created in the structure of crystals. Highlights: SAPO-34 molecular sieve was synthesized with a new and cost-effective surfactant (Triton X-100) as a green route. Catalytic performance was carried out under severe feed composition (72 wt% methanol in water) which is close to industrial conditions. The sample SP-34 (0.02) showed a promising performance for MTO reaction with 90% total olefins selectivity and more than 330 min lifespan. Compared with the best catalyst synthesized with TX-100 by Rami et al. (Synthesis and characterization of a nano-sized hierarchical porous AuSAPO-34 catalyst for MTO reaction: Special insight on the influence of TX-100 as a cheap and green surfactant, 2019), SP-34 (0.02) showed more than 12% improvement in the catalyst lifetime with comparable olefins selectivity. [ABSTRACT FROM AUTHOR]

Petroleum hydrocarbons are applied in various energy activities. If accidents happen, they may result in environmental contamination, especially in soil. Petroleum hydrocarbons have low evaporation rates and are adsorbed on the soil surface, making it necessary to treat contaminated soil before the pollutants spread to other areas. Soil washing with surfactant solution is a method used to treat petroleum hydrocarbon contamination. The process relies on surfactant properties which reduce surface tension and desorb diesel from soil particles prior to flushing out with water. The relationship between efficiency of diesel extraction from contaminated soil and factors of both single surfactants (Span20, Tween20, Tween80, Dehydol LS9) and mixed surfactants (Span20+Tween20, Span20+Tween80, Span20+Dehydol LS9) were investigated including hydrophile-lipophile balance (HLB) and interfacial tension (IFT) to select a suitable surfactant. Diesel was analyzed by GC-FID. Findings revealed that extraction efficiency significantly increased when the HLB of the surfactant increased in every solution pair (p = 0.05). Span20+Dehydol LS9 solution with HLB 12 showed the lowest IFT (17.767 ± 0.013 mN/m) and the highest diesel extraction efficiency (66.2%). The water washing process, repeated twice after washing with 1% (w/v) Span20+Dedydol LS9, resulted in less toxicity on germination and growth of tomato, rice, and green bean compared with diesel washing solution and fresh washing solution. Diesel-contaminated soil washing with mixed surfactant is an interesting alternative as an environmentally friendly soil treatment. [ABSTRACT FROM AUTHOR]

The inhibiting action of nonionic surfactants, namely, propoxylated fatty esters (PFE) with different number of propylene oxide toward the corrosion of Zn in 0.1 M HCl solutions was investigated. Four techniques were used in this study such as weight loss, galvanostatic polarization, potentiodynamic anodic polarization and electrochemical impedance spectroscopy. The inhibition efficiency of PFE compounds increases by increasing the concentrations of PFE, number of propylene oxide unit and with lowering temperature. The inhibition was interpreted by adsorption of PFE molecules on the Zn surface according Temkin's isotherm. Galvanstatic polarization indicated that the PFE acts as a mixed type inhibitor. PFE molecules inhibit the pitting corrosion of Zn in a solution containing Cl– ions by moving the pitting potentials into a more noble direction. The activation thermodynamic parameters such as , ΔH* and ΔS* are calculated and explained. [ABSTRACT FROM AUTHOR]

The paper focuses on the behaviour of nonionic surfactants (NISs) for enhanced oil recovery (EOR) processes with special reference to its applicability in the reservoirs of Upper Assam. The present work specifically studies three NISs, viz. Tergitol 15-s-7(Tg7), Tergitol 15-s-9 (Tg9) and Triton X 405(TX), based on their surface tension (ST), dynamic interfacial tension, hydrophilic–lipophilic balance, emulsion stability, aqueous stability, particle size analysis and phase behaviour. Simultaneously, crude oil from an oil field of upper Assam Basin was characterized based on API gravity, kinematic and dynamic viscosities, pour point and acid number. Core flood studies were conducted in the reservoir core to determine the recovery of crude oil during secondary water flood and EOR by NISs. It was observed that Tergitol 15-S-7 when mixed with Triton X-405 (Tg7TX) had the least interfacial tension (IFT) as compared to individual NIS and their mixtures. The recovery was found to be as high as 25.67% after secondary water flood from the original oil in place when Tg7TX followed by chase water was used as an exotic fluid for EOR. This work is an attempt to identify NISs mixtures for EOR for Upper Assam Basin. [ABSTRACT FROM AUTHOR]

The micellization behavior of amphoteric sodium 3-(N-dodecyl ethylenediamino)-2-hydroxypropyl sulfonate (C12AS) and nonionic octylphenol polyoxyethylene ether having ten oxyethylene glycol ether (OP-10) was investigated in water–isopropanol (IPA)–sodium chloride (NaCl) solution. The critical micelle concentration (cmc) including the single cmc for the single surfactant and the mixed cmc for the binary mixture of C12AS/OP-10 was determined by both tensiometry and the UV–Vis spectrometry. The mole fraction of component (X1 and X 1 ideal ) and activity coefficients (f1 and f2) in mixed micelle, the interaction parameter (β12) between two surfactants, and thermodynamic parameters (ΔGM and (∆Gmic) were estimated according to the pseudophase separation model, the Clint's model, the Rubingh's treatment, the Maeda's treatment, etc. Based on the regular solution theory, cosolvent effects on the interaction between two surfactants were analyzed. It shows that the mole fraction of C12AS in mixed micelle decreases with the concentration of IPA. The addition of IPA in the water/NaCl solution induces a non-monotonous change in the synergistic effect between the two surfactants. Thermodynamic data show that the increase in the concentration of IPA disfavors the spontaneous process of micellization. These phenomena are attributed to the changes in the hydrophobic effect of the hydrophobic group of the surfactant, the electrostatic repulsion between the ionic head groups of C12AS, and the steric effect of the head groups of two surfactants on adding IPA. [ABSTRACT FROM AUTHOR]

Abstract: Use of reactive dyes of red, blue and yellow colours for exhaustion dyeing of cotton conventional water-based dyeing method and PEG-based solvent-assisted reverse micelle dyeing method was investigated. Calibration curves of both dyeing approaches were established. The calibration results show that red dye can achieve higher absorbance value than yellow and blue dyes and the R-square of the curves can reach a value above 0.99 which indicates the curves are linear in structure and suitable for subsequent measurement. The values of substantivity factor (S), exhaustion factor (E), rate of fixation (R) and fixation factor (F) (SERF) are measured in percentage. The results reveal that using reverse micelle method can achieve higher dye absorption in both exhaustion and fixation processes, resulting in higher final exhaustion of dye in fibre than with the conventional water-based method. Therefore, the reverse micellar dyed samples generally can obtain higher dye absorption, lower reflectance percentage and darker shade in appearance than conventional water-based dyeing.Graphical abstract: [ABSTRACT FROM AUTHOR]

Nonionic surfactants have been utilized to improve the enzymatic hydrolysis of lignocellulosic materials. However, the role of surfactant adsorption affecting enzymatic hydrolysis has not been elaborated well. In this work, nonionic surfactants differing in their molecular structures, namely the polyoxyethylene sorbitan monooleate (Tween 80), the secondary alcohol ethoxylate (Tergitol 15-S-9), and the branched alcohol ethoxylate (Tergitol TMN-6), were studied for their effects on the enzymatic hydrolysis of palm fruit bunch (PFB). The PFB was pretreated with a 10% w/v sodium hydroxide solution and then hydrolyzed using the cellulase enzyme from Trichoderma reesei (ATCC 26921) at 50 °C and pH 5. The optimal conditions providing similar yields of reducing sugar required Tween 80 and Tergitol TMN-6 at 0.25% w/v, while Tergitol 15-S-9 was required at 0.1% w/v. All the surfactants improved the enzymatic conversion efficiency and reduced unproductive binding of the enzyme to lignin. In addition, the adsorption isotherm of cellulase was fit well by the Freundlich isotherm, while adsorption of the three nonionic surfactants agreed well with the Langmuir isotherm. Adsorption capacities of the three nonionic surfactants were consistent with their enhancement efficiencies in hydrolysis. The critical micelle concentration was observed as a key property of nonionic surfactant for adsorption capacity. [ABSTRACT FROM AUTHOR]

Electrokinetic removal of hydrophobic organic compounds from soil systems of various compositions making it possible to avoid an ingress of toxicants into groundwater has been investigated. Solubilization of impurities was ensured by using aqueous solutions of nonionic surfactants belonging to the group of oxyethylated alkylphenols. The distribution curves of residual impurity content were obtained after the termination of electric treatment of soils following the passage of different volumes of electroosmotic solutions containing surfactants. The specified curves allow us to predict the possibility of achieving the required treatment efficiency. [ABSTRACT FROM AUTHOR]

Monascus pigments are promising sources of natural food colorants, and their productivity can be improved by a novel extractive fermentation technology. In this study, we investigated the variations in pigment characteristics and biosynthetic gene expression levels in resting cell culture systems combined with extractive fermentation in Monascus anka GIM 3.592. Although the biomass was low at about 6 g/L DCW, high pigment titer of approximately 130 AU was obtained in the resting culture with cells from extractive fermentation, illustrating that it had a good biocatalytic activity for pigment synthesis. The oxidation-reduction potential value correlated with the rate of relative content of the intracellular orange pigments to the yellow pigments (O/Y, r > 0.90, p < 0.05), indicating that the change in pigment characteristics may be responsible for the cellular redox activity. The up- or down-regulation of the pigment biosynthetic genes ( MpFasA2, MpFasB2, MpPKS5, mppD, mppB, mppR1, and mppR2) in the resting culture with extractive culture cells was demonstrated by real-time quantitative polymerase chain reaction analysis. Moreover, the mppE gene associated with the yellow pigment biosynthesis was significantly ( p < 0.05) down-regulated by about 18.6%, whereas the mppC gene corresponding to orange pigment biosynthesis was significantly ( p < 0.05) up-regulated by approximately 21.0%. These findings indicated that extractive fermentation was beneficial for the biosynthesis of the intracellular orange pigment. The mechanism described in this study proposes a potential method for the highly efficient production of Monascus pigments. [ABSTRACT FROM AUTHOR]

We have investigated the interaction of nonionic conventional surfactants, Brij 35 and Brij 58, with three homologous oxy-diester-linked cationic gemini surfactants, 2,2′-[(oxybis(ethane-1,2-diyl))bis(oxy)]bis( N-alkyl- N, N-dimethyl-2-oxoethanaminium) dichloride (C-DEG-C, m = 12, 14, 16), by the surface tension measurements at 30 °C. The tensiometric data were used to calculate the critical micelle concentration (cmc) of the pure and mixed (equimolar) gemini-conventional surfactant systems. cmc values of the gemini surfactants are well below those of their monomeric counterparts which contain the same number of carbon atoms in the hydrophobic tail per polar head group. From the experimentally obtained cmc values of the binary surfactant mixtures (1:1), various physicochemical parameters were calculated. Lower cmc values of the binary solutions than the ideal cmc and also the negative β values indicate that the interactions between the component surfactants of the mixed systems are synergistic in nature; the C-DEG-C + Brij 58 system is an exception, in which antagonism is observed. The occurrence of mixed micellization is indicated by the decrease in cmc of the binary surfactant solutions and nonideality of the mixed systems. Interaction parameters ( β , β ) of the mixed systems were evaluated by using the theoretical models suggested by Clint, Rubingh, and Rosen. Negative values of β and $$ \varDelta {G}_{\mathrm{ex}}^m $$ (excess free energy of mixing) indicate an overall attractive force in the mixed state. The cationic gemini surfactant with lower chain length shows higher interaction with the nonionic conventional surfactants. [ABSTRACT FROM AUTHOR]

The structure and properties of a water-oil emulsion have been studied. The ultrafiltration of the water-oil emulsion has been performed with the use of spiral wound and hollow fiber membranes to separate the emulsion into a filtrate and a concentrate. The effect of pH on the following performance characteristics of the ultrafiltration process has been studied: the efficiency and the degree of separation of oil products and nonionic surfactants. It was found that an increase in the pH value of the emulsion decreased the efficiency of membranes and the degree of separation of nonionic surfactants. It has been found that a Raifil UF membrane effectively rejects oil products from acidic emulsion and, on the contrary, an EMU 45-300 membrane is effective in an alkaline medium. This behavior has been associated with to a positive surface charge of the EMU 45-300 membrane. The maximum efficiencies and degrees of separation of oil products and nonionic surfactants from emulsions with the use of the Raifil UF ultrafiltration membrane and the EMU 45-300 membrane have been attained in the pH ranges from 2.1 to 2.9 and from 2.2 to 2.5, respectively. After ultrafiltration, the size of particles in the filtrate increased by a factor of about 18 due to the coalescence of oil particles in the near-membrane layer because of polarization effects. The increase in the particle size of the dispersed phase in the filtrate can also be explained by a positive surface charge of polysulfonamide membranes. [ABSTRACT FROM AUTHOR]

The use of critical nanoemulsions based on toluene, acetone, and water for isolation and identification of individual esters has been demonstrated. Analytical equations for the calculation of the eluent efficiency coefficient for individual oxyethyl esters of n-aliphatic acids have been suggested. [ABSTRACT FROM AUTHOR]

Monascus pigments that were generally produced intracellularly from Monascus spp. are important natural colorants in food industry. In this study, change of pigment metabolism and secretion was investigated through fed-batch extractive fermentation and continuous extractive fermentation. The biomass, secreting rate of pigment and total pigment yield closely correlated with the activated time of extractive fermentation as well as the composition of feeding nutrients. Metal ions played a key role in both the cell growth and pigment metabolism. Nitrogen source was necessary for a high productivity of biomass but not for high pigment yield. Furthermore, fermentation period for the fed-batch extractive fermentation could be reduced by 18.75% with a nitrogen source free feeding medium. Through a 30-day continuous extractive fermentation, the average daily productivity for total pigments reached 74.9 AU day with an increase by 32.6 and 296.3% compared to that in a 6-day conventional batch fermentation and a 16-day fed-batch extractive fermentation, respectively. At the meantime, proportions of extracellular pigments increased gradually from 2.7 to 71.3%, and yellow pigments gradually became dominated in both intracellular and extracellular pigments in the end of continuous extractive fermentation. This findings showed that either fed-batch or continuous extractive fermentation acted as a promising method in the efficient production of Monascus pigments. [ABSTRACT FROM AUTHOR]

The effect adsorption layers of nonionic surfactant (pluronic P123) have on the distribution of nanodiamonds (NDs) between aqueous and organic phases is studied with radioactive tracers using compounds labeled with tritium. The values of reversible and irreversible adsorptions of P123 on NDs are determined. It is shown that the distribution coefficients of NDs modified by irreversibly adsorbed layers of P123 are several times higher than those of raw nanodiamonds. This result is explained by the hydrophobization of an ND's surface, as is shown by data obtained via interfacial tensiometry and wetting. [ABSTRACT FROM AUTHOR]

Effects of monovalent and monatomic salts on lamellar repeat distances d of nonionic surfactants (monomyristolein and $${\mathrm {C_{12}E_{2}}}$$ ) are investigated using small-angle X-ray diffraction. The lamellar repeat distances (sum of thicknesses of a bilayer and a sandwiched water layer) increase with increasing salt concentration with a strong anion dependence (Br $$^->$$ Cl $$^- $$ ). The increase of the thickness of the water layer is found to dominate the increase in d. Since the anion dependence is inconsistent with the ion dependence of the strength of the primary hydration, we reported previously (Hishida et al. J Chem Phys 142:171101, 2015), the hydration force classically considered is not the origin of the increase in d. This means the increase in d cannot be explained by the existing model of the forces between neutrally charged bilayers. The temperature dependence of d also supports the necessity for a new mechanism of the effect of ions. The new mechanism seems to be related to the water structure beyond the primary hydration water, i.e., the secondary hydration water, which depends on the ion species. [ABSTRACT FROM AUTHOR]

$$\hbox {CO}_{2}$$ flood is one of the most successful and promising enhanced oil recovery technologies. However, the displacement is limited by viscous fingering, gravity segregation and reservoir heterogeneity. Foaming the $$\hbox {CO}_{2}$$ and brine with a tailored surfactant can simultaneously address these three problems and improve the recovery efficiency. Commonly chosen surfactants as foaming agents are either anionic or cationic in class. These charged surfactants are insoluble in either $$\hbox {CO}_{2}$$ gas phase or supercritical phase and can only be injected with water. However, some novel nonionic or switchable surfactants are $$\hbox {CO}_{2}$$ soluble, thus making it possible to be injected with the $$\hbox {CO}_{2}$$ phase. Since surfactant could be present in both $$\hbox {CO}_{2}$$ and aqueous phases, it is important to understand how the surfactant partition coefficient influences foam transport in porous media. Thus, a 1-D foam simulator embedded with STARS foam model is developed. All test results, from different cases studied, have demonstrated that when surfactant partitions approximately equally between gaseous phase and aqueous phase, foam favors oil displacement in regard to apparent viscosity and foam propagation speed. The test results from the 1-D simulation are compared with the fractional flow theory analysis reported in the literature. [ABSTRACT FROM AUTHOR]

Growing cell submerged culture is usually applied for fermentative production of intracellular orange Monascus pigments, in which accumulation of Monascus pigments is at least partially associated to cell growth. In the present work, extractive fermentation in a nonionic surfactant micelle aqueous solution was utilized as a strategy for releasing of intracellular Monascus pigments. Those mycelia with low content of intracellular Monascus pigments were utilized as biocatalyst in resting cell submerged culture. By this means, resting cell submerged culture for production of orange Monascus pigments was carried out successfully in the nonionic surfactant micelle aqueous solution, which exhibited some advantages comparing with the corresponding conventional growing cell submerged culture, such as non-sterilization operation, high cell density (24 g/l DCW) leading to high productivity (14 AU of orange Monascus pigments at 470 nm per day), and recycling of cells as biocatalyst leading to high product yield (approximately 1 AU of orange Monascus pigments at 470 nm per gram of glucose) based on energy metabolism. [ABSTRACT FROM AUTHOR]

Microemulsions are interesting formulations for cosmeceutical applications due to their good appearance, high solubilization power, thermodynamic stability, and enhancement of skin penetration. In addition, they can spontaneously form when suitable types and amounts of components are simply mixed. In this study, the phase behavior of the nonionic systems with various parameters was studied by construction of phase diagrams using titration method. Natural oils, i.e., coconut oil (CO), rice bran oil (RBO), and palm oil (PO), were analyzed for their fatty acid compositions and then mixed with blends of nonionic surfactants (Tween80: Span80) and water or mixtures of water and a cosolvent, propylene glycol (PG), to find the microemulsion regions. Subsequently, some microemulsions were selected for physical characterization. The largest microemulsion regions which were obtained from CO, RBO, and PO covered the sizes of 11.65, 9.84, and 9.24 %, respectively. The surfactant mixture at weight ratio of 1:1 was the most suitable for CO and PO, but for RBO, it was 2:1. PG could increase the microemulsion regions of PO from 9.24 to 15.33 %, depending on PG concentrations. Hence, the sizes of the microemulsion regions were related to oil types, surfactant mixtures, and ratios between water and PG. The studied microemulsions were water-in-oil (w/o) type, and their internal droplets were in the nanosize range. They exhibited Newtonian flow behavior and their mean viscosity values were from 247.53 to 690.35 cP which were correlated with the types and concentrations of the components in the formulations. In conclusion, natural oils could form w/o microemulsions with nonionic surfactants. The microemulsion formation and characteristics were related to many parameters of the components. [ABSTRACT FROM AUTHOR]

Four eco-friendly ('green') non-ionic surface active agents were synthesized via reaction of fatty acids obtained from hydrolysis of castor oil with vanillin. The products were then reacted with monoethanol amine to form a vanillin ester Schiff base. The vanillin ester Schiff base was ethoxylated using ethylene oxide gas in the presence of tri-ethyl amine as a catalyst to give the desired non-ionic surfactants. The chemical structures of the obtained surfactants were characterized using FTIR and HNMR spectroscopy. The inhibition effect of the four synthesized non-ionic surfactants derived from vanillin (VE15, VE20, VE40, and VE60) on the corrosion of carbon steel in acidic media of 0.5-M HCl was studied by weight loss, potentiodynamic and electrochemical impedance spectroscopy measurements. The results show that the synthesized inhibitors are effective inhibitors even at very low concentrations, and the adsorption on carbon steel surface obeys the Langmuir adsorption isotherm. Potentiodynamic polarization curves reveal that the synthesized inhibitors behave as mixed-type inhibitors. Adsorption of used inhibitors led to a reduction in the double layer capacitance and an increase in the charge transfer resistance. Calculated Δ G values indicated that the mechanism by which these inhibitors adsorb onto carbon steel in 0.5-M HCl solution is chemical adsorption. The surface activities of the synthesized surfactants were determined using surface tension measurements. The biodegradability of these surfactants indicates that the compounds readily degrade in the environment and can be considered as green corrosion inhibitors. [ABSTRACT FROM AUTHOR]

In the last decade, increasing interest on the use of aqueous micellar solution has been found in the field of separation science. The unique physical and chemical properties of ionic liquids make them most suitable candidates as an additive with nonionic surfactants in cloud point extraction. A surfactant-mediated cloud point extraction process has been adopted for the removal of Coralene red dye using tetraethyl ammonium tetrafluoroborate ionic liquid as an additive with nonionic surfactant Triton X-100. The detailed study on effect of various operating parameters such as temperature, time, concentration of surfactant, dye and IL on extraction of dye has been carried out to find out optimum conditions. The extraction of dye was found to be increased with temperature, time, surfactant concentration and IL concentration. A developed Langmuir isotherm was used to compute the feed surfactant concentration required for the removal of Coralene red dye up to an extraction efficiency of 90 %. The effect of temperature and concentration of surfactant and dye on various thermodynamic parameters was examined, and it was found that the values of Δ G increased with temperature and decreased with surfactant and dye concentration. The values of Δ H and Δ S increased with surfactant concentration and decreased with dye concentration. The developed approach for IL-assisted cloud point extraction has proved to be an efficient and green route for extraction of Coralene red from water sample. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A series of nonionic surfactants were synthesized from gallic acid and polyethylene glycols with different molecular weights. Chemical structures of the surfactants were confirmed using elemental analysis, infrared and nuclear magnetic resonance (H-NMR) spectroscopy. Surface activities of the surfactants in their solutions were determined by surface tension measurements. Increasing the polyethylene glycol chain length increased the surface activity of the surfactants in solutions. Measurements of interfacial tension between surfactants solutions and substrates with different polarity showed that the type of substrates plays functioning role on the interfacial properties. Thermodynamic properties of adsorption and micellization processes showed their tendency towards adsorption at solution interface and micellization in their solutions. Results showed reasonable surface activities compared to conventional nonionic surfactants. [ABSTRACT FROM AUTHOR]

Recent progress in modeling of the surfactant behavior from atomistic to continuous at the air/water interface across different space-time scales is reviewed. Advantages and disadvantages of modern quantum mechanical, molecular dynamical, and mesoscale methods are discussed for description of interactions between amphiphilic molecules leading to formation of 2D films. The use of nonempirical and semiempirical methods for assessment of the thermodynamic and structural parameters of large van der Waals complexes is of particular interest. An approach for calculation of the thermodynamic and structural parameters of clusterization for nonionic surfactants at the air/water interface is proposed on the basis of the quantum chemical semiempirical PM3 method. This approach implicitly takes into account the influence of the interface on the surfactant molecules via stretching and orienting effect. The calculations are carried out in the supermolecule approximation for a limited number of small amphiphilic aggregates with different alkyl chain. The correlation analysis of the calculated data array provides the increments contributing by the intermolecular CH · · · HC interactions and interactions between hydrophilic parts into the thermodynamic parameters of formation and clusterization. Obtained increments are further used for constructing the dependencies of the thermodynamic clusterization parameters per one monomer on the alkyl chain length for large clusters up to 2D films. In the framework of the proposed theoretical approach, the next parameters are calculated as follows: enthalpy, entropy, and Gibbs' energy of clusterization for 11 homologous series of nonionic surfactants, threshold chain length enabling the process of monolayer formation at standard conditions, the 'temperature effect' of clusterization, and the structural parameters of the monolayer unit cell (particularly the tilt angle) depending on the size of the hydrophilic headgroup of the amphiphilic compound. [ABSTRACT FROM AUTHOR]

Monascus species can produce various secondary metabolites of polyketide structure. In the current study, it is found that an interesting phenomenon, i.e., submerged culture of Monascus species in an aqueous solution majorly accumulated intracellular orange Monascus pigments exhibiting one peak at 470 nm with absorbance of 32 OD while extractive fermentation in a nonionic surfactant micelle aqueous solution produced extracellular and intracellular yellow Monascus pigments exhibiting one peak at 410 nm with absorbance 30 OD and 12 OD, respectively. The spectrum profiles of both intracellular and extracellular Monascus pigments were affected by surfactant loading, extractive fermentation time, and surfactant adding time. Meanwhile, the instability of orange Monascus pigments in the extracellular nonionic surfactant micelle aqueous solution was also confirmed experimentally. The mechanism behind this phenomenon is attributed to the export of intracellular yellow Monascus pigments into its broth by extractive fermentation. The transferring of intracellular yellow Monascus pigments into its broth blocks yellow Monascus pigments from further enzymatic conversion or eliminates the feedback inhibition of yellow Monascus pigments based on the biosynthetic pathway of Monascus pigments. [ABSTRACT FROM AUTHOR]

In nuclear power plants and nuclear laboratories, laundry wastewater is generated from decontaminating polluted instruments, worker's clothes and taking shower after work. Laundry wastewater contains radionuclides and surfactants. The surfactants included in laundry wastewater affect the extraction of radionuclides. Therefore, surfactants should be removed before extraction of radionuclides. The objective of the present work is to assess the ability of commercial charcoal for the removal of nonionic surfactants, where, commercial charcoal is a commonly available adsorbent for treatment. Charcoal was characterized using different analytical techniques. The isotherm models and thermodynamic parameters were evaluated. Charcoal was applied to the removal of surfactant from liquid radioactive waste. The data obtained can be used for designing a plant for treatment of surfactant rich water and wastewater economically. [ABSTRACT FROM AUTHOR]

This work presents the results of tribological investigations of lubricating substances composed of water and a nonionic surfactant: lauric acid random copolyether (LPE), as additive. At the current stage of investigation, aqueous solutions with LPE additives are prepared and subsequently the lowering friction and reducing wear behaviors are tested by means of friction/wear tester, in conjunction with that the film forming properties experiments are carried out with a nanoscale film thickness measure apparatus. The contact is under condition of steel-steel tribo-pair. The results show that the coefficient of friction measured decreases considerably to about over 60% relative to water. The film thickness data of friction process lubricated by aqueous solutions with LPE added show that the lubrication is in boundary lubrication regime. The results indicate that aqueous solutions with LPE added can be used to improve the lubricity and they may be applied to real tribological systems. [ABSTRACT FROM AUTHOR]

Cloud point extraction (CPE) is an efficient and green separation technology as an alternative to conventional organic solvent extractions. How to accelerate the phase separation of aqueous surfactant solutions conveniently is of great importance. In this study, the effect of power ultrasound on the phase separation of aqueous solutions of a nonionic surfactant, Triton X-114 [(1,1,3,3-tetramethylbutyl) phenyl-polyethylene glycol], has been studied as a function of temperature by means of rheo-small angle light scattering. It is found that anomalous viscosity enhancements and micron-sized scattering aggregates are observed for the surfactant solutions after ultrasound irradiation. The aggregate growth is quantified by the characteristic length of the aggregates. It is proposed that ultrasonic cavitation can promote the aggregation or transition of surfactants in the aqueous solutions, resulting in the formation of micrometer-scale phase-separated droplets. This work may advance further understanding of the controlled transformation of aggregates in surfactant solutions via power ultrasound and promote its applications in CPE. [ABSTRACT FROM AUTHOR]

We report an autopsy case of death due to accidental ingestion of a liquid laundry detergent with special regard to the histochemical findings. A female inpatient suffering from schizophrenia in a psychiatric institution, was found unconscious lying on the floor of her room, with a container of detergent nearby, and died despite intensive life-support measures. At autopsy, the stomach and duodenum contained whitish translucent foamy viscous fluid, and the mucous membranes, from the esophagus to the duodenum, had diffuse erosions with congestion and edema. There was otherwise no significant pathology other than signs of acute death and hemolysis. Toxicological investigations detected 1-methyl-4-prop-1-en-2-ylcyclohexene (detergent additive) in the gastric contents using headspace-gas chromatography/mass spectrometry, and a nonionic surfactant by a color identification test. Although these substances could not be detected in the blood, body fluid or viscera, histochemical examination using Oil red O demonstrated droplet-like staining in the pulmonary alveoli, suggesting aspiration of detergent, and similar staining in the vasculature of the lung, Kupffer cells of the liver, Bowman capsules of the kidney, and capillaries of the brain, suggesting the systemic effect of ingested/aspirated detergent. These findings were in keeping with death from ingestion of detergent and demonstrated the importance of preventing accidents such as this in healthcare facilities for elderly people. [ABSTRACT FROM AUTHOR]

Knowledge of colloid straining mechanism in porous media is of importance for protecting groundwater from being contaminated by biocolloids (e.g., bacteria and protozoa) and by contaminants whose transport can be facilitated by mobile particles. This study examined effects of flow velocity on colloid straining in porous media under unfavorable chemical conditions. Saturated column experiments were conducted using glass beads as collector and a $$3\,\mu \text{ m}$$ carboxylate-modified polystyrene latex microsphere as model colloid. To unambiguously examine colloid straining mechanisms, attachment was minimized by extensively cleaning the collectors and adopting deionized water as solution. Results show that increasing flow velocity decreases colloid straining under unfavorable chemical conditions, in agreement with to theoretical finding in literature. This study additionally examined effects of nonionic surfactant (Triton X-100) on colloid straining in porous media under unfavorable chemical conditions. Results show that the addition of Triton X-100 decreases colloid straining and the decrease is enhanced by increasing the concentration of Triton X-100. [ABSTRACT FROM AUTHOR]

The recovery of Tween 80 from a liquid residue, obtained after washing of a contaminated soil with p-Cresol, was studied by selective adsorption of p-Cresol with activated carbons. A modified expression of the Langmuir equation was succesfully used to predict the adsorption isotherms of p-Cresol in the absence and presence of different surfactant concentrations. The presence of surfactant seems to modify the adsorption equilibrium, but it does not produce any significant influence on the adsorption kinetic of p-Cresol. A mathematical model was developed to predict the optimum activated carbon dosage demanded to reduce the p-Cresol concentration as a function of the surfactant concentration, also obtaining the corresponding surfactant loss. The regenerated solution was favorably used as washing solution in a new contaminated soil. These results indicate that this technique can be adequate to recover the surfactant solution, with a relatively minimal loss, for a subsequent application. [ABSTRACT FROM AUTHOR]

A cloud point extraction coupled with high performance liquid chromatography (HPLC/UV) method was developed for the determination of Δ-tetrahydrocannabinol (THC) in micellar phase. The nonionic surfactant 'Dowfax 20B102' was used to extract and pre-concentrate THC from cannabis resin, prior to its determination with a HPLC-UV system (diode array detector) with isocratic elution. The parameters and variables affecting the extraction were investigated. Under optimum conditions (1 wt.% Dowfax 20B102, 1 wt.% NaSO, T = 318 K, t = 30 min), this method yielded a quite satisfactory recovery rate (~81 %). The limit of detection was 0.04 μg mL, and the relative standard deviation was less than 2 %. Compared with conventional solid-liquid extraction, this new method avoids the use of volatile organic solvents, therefore is environmentally safer. [ABSTRACT FROM AUTHOR]

Surfactants have been used for environmental remediation to remove hydrophobic organic compounds (HOCs) in water and soil. However, there are limited studies on the use of surfactants in confined micelle arrays to remove pesticides and polycyclic aromatic hydrocarbons from water. We studied the recovery of HOCs using two confined surfactants: nonionic Triton X-100 and cationic 3-(trimethoxysily)propyl-octadecyldimethyl-ammonium chloride (TPODAC). The micelle arrays were confined on a mesoporous silica matrix deposited onto a magnetic iron core. These magnetic, dispersible sorbents can be used to recover HOCs, minimizing the application of surfactants when compared to soil-washing techniques. The TPODAC-based sorbent had better average recovery of the HOCs studied compared to the Triton-X sorbent, and was, in general, comparable to activated carbon. It performed well with the chlorinated pesticides, in part due to additional interactions between the cationic sites and the polar compounds. [ABSTRACT FROM AUTHOR]

'Milking processing' describes the cultivation of microalgae in a water-organic solvent two-phase system that consists of simultaneous fermentation and secretion of intracellular product. It is usually limited by the conflict between the biocompatibility of the organic solvent to the microorganisms and the ability of the organic solvent to secret intracellular product into its extracellular broth. In the present work, submerged cultivation of Monascus in the nonionic surfactant Triton X-100 micelle aqueous solution for pigment production is exploited, in which the fungus Monascus remains actively growing. Permeabilization of intracellular pigments across the cell membrane and extraction of the pigments to the nonionic surfactant micelles of its fermentation broth occur simultaneously. 'Milking' the intracellular pigments in the submerged cultivation of Monascus is a perstraction process. The perstractive fermentation of intracellular pigments has the advantage of submerged cultivation by secretion of the intracellular pigments to its extracellular broth and the benefit of extractive microbial fermentation by solubilizing the pigments into nonionic surfactant micelles. It is shown as the marked increase of the extracellular pigment concentration by the submerged cultivation of Monascus in the nonionic surfactant Triton X-100 micelle solution. [ABSTRACT FROM AUTHOR]

In order to develop turbulent drag-reducing technology by using an environmentally friendly additive in a water-transporting system, the drag reducing characteristics in a non-ionic surfactant (Oleyldimethylamineoxide, ODMAO) dilute aqueous solution flowing in a circular pipe of 5 mm diameter have been experimentally investigated with an air-driven fluid resistance test device. The rheological characteristics of the solution have also been examined by a rheometer with a cone-plate flow cell. The results show that the ODMAO solutions are drag-reducing when concentration is 400 ppm or higher, that the critical Reynolds number corresponding to the maximum drag reduction rate increases with both concentration and temperature, and that the maximum drag reduction rate can reach up to 70% in the straight pipe. At low shear rates, the shear viscosity of ODMAO solutions with a relatively high drag-reduction behaves similarly to Newtonian fluids; at above a certain critical shear rate, it is firstly shear-thickening, then shear-thinning. Such shear-rate-dependent characteristics of the shear viscosity are attributed to the different transitions of micellar network structure induced by different shear rates. Relaxation of shear stress after removing an applied constant shear rate at which the solution is in the SIS (shear-induced structure) state is found to be well expressed by a 2-step Maxwell model with a tail relaxation time much shorter than that for a drag-reducing cationic surfactant, which indicates that for the ODMAO solution, a viscoelasticity as strong as a drag-reducing cationic surfactant is not needed to realize turbulent drag-reduction. [ABSTRACT FROM AUTHOR]

The extraction of polycyclic aromatic hydrocarbons (PAHs) from petroleum source rock by nonionic surfactants with the assistance of microwave irradiation was investigated and the conditions for maximum yield were determined. The results showed that the extraction temperatures and type of surfactant have significant effects on extraction yields of PAHs. Factors such as surfactant concentration, irradiation power, sample/solvent ratio and mixing surfactants (i.e., mixture of surfactant at specific ratio) also influence the extraction efficiencies for these compounds. The optimum temperature for microwave-assisted nonionic surfactant extraction of PAHs from petroleum source rock was 120 °C and the best suited surfactant was Brij 35. The new method showed extraction efficiencies comparable to those afforded by the Soxhlet extraction method, but a reduction of the extraction times and environmentally friendliness of the new nonionic surfactant extraction system are clear advantages. The results also show that microwave-assisted nonionic surfactant extraction is a good and efficient green analytical preparatory technique for geochemical evaluation of petroleum source rock. [ABSTRACT FROM AUTHOR]

The direct electron transfer and adsorption behavior of hemoglobin (Hb) in a series of surfactants with different poly(ethylene oxide) (PEO) unit lengths on a glassy carbon electrode have been studied. With a surfactant of appropriate PEO unit length, the surfactant film-modified electrode exhibited a more stable adsorption state with a larger surface coverage of Hb and a more positive formal potential, which can be attributed to the effect of hydrogen bonding between proteins and surfactants. The electrochemical behavior of surfactants with different PEO unit lengths is discussed in detail. Moreover, UV-visible spectroscopy demonstrated that the structure of Hb was not destroyed in the surfactant films. The electrocatalytic activity of hydrogen peroxide on three neutral surfactant-modified electrodes has also been investigated. [ABSTRACT FROM AUTHOR]

Self-aggregation of polyoxyethylene (POE)-type nonionic surfactants in ionic liquids, 1-butyl- and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (bmimCFSO and emimCFSO), was investigated by means of H-NMR chemical shift, dynamic light-scattering (DLS), and surface tension measurements. The surfactants showed no definite aggregate formation in bmimCFSO. This shows a remarkable contrast to the previous observation in bmimBF and bmimPF, and demonstrates an importance of anion species to determine the property of ionic liquids as a solvent to support the self-assembly of amphiphilic compounds. On the other hand, the surfactants formed micelles in emimCFSO, which shows an importance of alkyl chain attached to imidazolium ring to determine the solvophobic interaction between surfactant hydrocarbon chains in imidazolium-based ionic liquids. The low solvophobicity of the surfactants to the ionic liquid composed of imidazolium cation with long alkyl chain is attributed to an affinity of the surfactant hydrocarbon chain to the imidazolium alkyl chain. The values of micellization parameters and surface adsorption parameters obtained for the surfactant solutions in emimCFSO are reported. [ABSTRACT FROM AUTHOR]