Cationic Cetyltrimethylammonium Bromide Research Articles

Анализ распространения фитоплазм почернения древесины и золотистого пожелтения на виноградниках Краснодарского края

The purpose of research is to study the spread of phytoplasma infection in the vineyards of the Krasnodar Region using the PCR method. The object of the study is grape plants of various varieties with external symptoms of phytoplasma infection. The material for total DNA extraction was symptomatic leaves (their veins and petioles) collected from plantings of Shiraz, Chardonnay, Cabernet Sauvignon, Saperavi, Mizar, Moldova, Augustine, Pinot Blanc, Riesling, and Aligote varieties. DNA extraction was carried out using a buffer based on the cationic detergent CTAB (cetyltrimethylammonium bromide), according to the protocol recommended by EPPO (European plant protection organization) for the isolation of phytoplasmas from grape plant material. Sampling was carried out in industrial vineyards of the Krasnodar Region in 9 different geographical locations of the Novorossiysk, Temryuk and Anapa Regions. DNA was isolated from symptomatic leaves according to the protocol recommended by EPPO (European plant protection organization). Determination of the presence of phytoplasma infection was carried out by real-time PCR on a Quant Studio 5 amplifier using a commercial kit designed to detect phytoplasmas – Candidatus Phytoplasma solani and Candidatus Phytoplasma vitis (Synthol) and a test system recommended by EPPO. Using a kit produced by Synthol, 239 samples were analyzed, including 12 rechecked with markers recommended by EPPO. As a result of the analysis, it was found that DNA of Candidatus Phytoplasma solani was present in 113 samples studied. DNA from the phytoplasma Candidatus Phytoplasma vitis, which causes golden yellowing of leaves, was not detected in any of the analyzed samples.

Effect of surfactants on the interfacial viscoelasticity and stability of silk fibroin at different oil-water interfaces.

The biocompatible amphiphilic silk fibroin, extracted from domesticated silkworms, can adsorb at the oil-water interface and form elastic interfacial layers. In this study, three surfactants (cationic cetyltrimethylammonium bromide, the nonionic polyoxyethylene sorbitan monolaurate, and the anionic sodium dodecyl sulfate) were selected to investigate, through interfacial shear rheology, the influences of surfactants on the interfacial viscoelasticity and stability of silk fibroin at the interfaces between water and two different oils. The presence of surfactant prolongs the equilibration time and enhances the interfacial elastic modulus and toughness of the interfacial silk fibroin layers, especially at the nonpolar dodecane-water interface. However, when the surfactant exceeds a critical concentration, the shear modulus and stability of interfacial silk fibroin layers begin to decrease due to the competitive adsorption of surfactant molecules and the weakening of the protein network. Owing to electrostatic interactions, the ionic surfactants cetyltrimethylammonium bromide and sodium dodecyl sulfate can form more hydrophobic complexes with silk fibroin, which results in higher shear moduli than for silk fibroin and silk fibroin-polyoxyethylene sorbitan monolaurate mixture. Both the surfactant type and oil polarity play important roles in the adsorption, shear viscoelasticity, and stability of silk fibroin at the oil-water interface. Enhanced interactions between a silk fibroin-surfactant mixture and the oil phase delay the equilibration of the adsorption layers but strengthen the stability of interfacial layers. © 2023 Society of Chemical Industry.

Effect of glycerol on micellization of quasi-binary mixture of zwitterionic cocamidopropyl hydroxysultaine and cetyltrimethylammonium bromide in aqueous solution

The micellization behavior of quasi-binary mixture of zwitterionic cocamidopropyl hydroxysultaine (CAPHS) with cationic cetyltrimethylammonium bromide (CTAB) was investigated both in aqueous solution and in glycerol-water. Both the tensiometric and the conductive techniques were adopted to determine the critical micelle concentrations (cmc) of individual and mixed surfactants. In the framework of the regular solution theory and based on the pseudophase separation model, some micellization and thermodynamic parameters were estimated by the Rubingh’s and the Clint’s models. The results indicate that the nonideal mixing of CAPHS with CTAB and the synergistic interaction between them play vital roles on the reduction of mixed cmc, the amplitude of synergistic interaction depends on the composition of mixture and the presence of glycerol induces the increase in the individual and mixed cmc values and the change of the participation of CAPHS in mixed micelle with the composition in bulk solution. The electrostatic repulsion, the diversity of molecular conformation and the steric hindrance can account for the formation of mixed micelle and the difference in micellar composition. Thermodynamic parameters show that the entropy makes overwhelming contributions on the spontaneous process of micellization, the release of mixing heat makes the stable mixed micelle formed and the presence of glycerol makes for reducing the contribution of entropy and forming the more stable mixed micelle. These findings help with understanding the interaction behavior between two species and the effect of glycerol and further providing some information for the design of the related surfactant formulations.

Decolorization and mineralization of methylene blue by potassium permanganate

Methylene blue (MB)-permanganate redox reaction has been studied spectrophotometrically in absence and presence of cationic cetyltrimethylammonium bromide (CTAB). The UV–visible spectroscopy reveals the presence of intermediate reaction products (Azure B, Azure A, and thionine) during interaction confirming the real degradation of MB. The gas chromatography-mass spectrometry (GC-EIMS) was used to establish the formation of MB degradation products. The electron transfers lead to a rapid N-demethylation oxidative reaction to form colored intermediary compounds. The key factors ([MnO4−], [MB], [H2SO4], and temperature) that affect the degradation rate of MB solution are analyzed. The redox reaction proceeds through a complex formation between the MB and MnO4−. The position of absorption band of MB was shifted from 666 nm to 603 nm with increasing the reaction time. The degradation efficiency decreases drastically from 82.1 % to 41.8 % in presence of 1.0 mM H2SO4. The results show that the degradation rate in acidic solutions is lower than that in neutral reaction media. The MnO2 was not formed as the product with H2SO4. The degradation efficiency of MB decreases with increasing CTAB concentrations. Sub-micellar inhibitory role of CTAB indicates that the MnO4− interact with positive head group of CTAB, and inhibit the oxidation of MB.

Spectroscopic insights for the enhanced partitioning and removal of Reactive Violet 5 by mixed micellar formulations under optimized conditions: An ionic-nonionic mechanistic approach

This study demonstrates MEUF (micellar enhanced ultrafiltration) as an effective method for the removal of Reactive Violet 5 (RV5) coming from the synthetic waste. MEUF technique is currently employed to decrease aqueous systems toxicity by employing cationic surfactants micellar media, specifically CPC (cetylpyridinium chloride) and CTAB (Cetyltrimethylammonium bromide). The study also examines the impact of nonionic surfactant on the addition of Triton X-100 (TX-100), on solubilizing capacity of the cationic surfactants. Our goal is to determine the optimal conditions for achieving maximum removal efficiency. RV5 partitioning constant, Kb as well as Gibbs energy of the partition ΔGp determines surfactant and dye molecules interaction. Dye molecules initially interact with ionic surfactants to form ion pairs. Subsequently, these ion pairs become incorporated into micelles and later on can subsequently be removed by MEUFThe maximum values of ΔGp (free energy of partition) were determined to be −42.30 kJmol−1 and −37.15 kJmol−1 using cationic surfactants, CPC and CTAB, respectively. Increase in pollutant size results in easy filtration. This study examines the impact of different factors, such as pH, transmembrane pressure, electrolyte (NaCl), surfactant concentration and revolutions per minute (RPM), on the removal of RV5 from an aqueous system. MEUF efficiency has been evaluated through the determination of permeate flux and rejection percentage values. It has been noticed that both surfactants had the potential to effectively encapsulate RV5. However, overall, the highest R% (rejection percentage) of 97.17% was attained.

Surfactants interaction with sulfathiazole: Spectroscopic, conductometric, and thermodynamic approach

Taking into the account the advantages of surfactant micelles as drug carrier, the interaction of sulfathiazole (STZ) with three types of surfactants, namely, cationic cetyltrimethylammonium bromide (CTAB), anionic sodium dodecyl sulfate (SDS), and non-ionic t-octylphenoxypolyethoxyethanol (TX-100) has been studied by using UV–visible spectroscope and conductivity measurements. The critical micelle concentration (CMC), degree of ionization (α), counter ion binding constant (β), free energy change of micellization (ΔG0m), relative solubility (St/S0), STZ-surfactant interaction constant (θ), approximate number (n) of STZ molecules incorporated per micelle, heat capacity (ΔC0m), and transfer of thermodynamic parameters were calculated and discussed for both the systems. The CMC values of CTAB and SDS were found to decrease in presence of increasing STZ concentrations. The values of counter ions dissociation were also found to be dependent of temperature. The ΔG0m values are obtained to be negative of both systems. A comparison of the binding constants (KC) calculated from the Kawamura equation indicated that the solubilization tendency of STZ with CTAB is much higher than that with SDS micelles. However, this interaction was weak since no significant change in the micellization phenomenon was observed with TX-100 under our experimental conditions.

Low‐Cost Multi‐Function Electrolyte Additive Enabling Highly Stable Interfacial Chemical Environment for Highly Reversible Aqueous Zinc Ion Batteries

AbstractThe practicality of aqueous zinc ion batteries (AZIBs) for large‐scale energy storage is hindered by challenges associated with zinc anodes. In this study, a low‐cost and multi‐function electrolyte additive, cetyltrimethyl ammonium bromide (CTAB), is presented to address these issues. CTAB adsorbs onto the zinc anode surface, regulating Zn2+ deposition orientation and inhibiting dendrite formation. It also modifies the solvation structure of Zn2+ to reduce water reactivity and minimize side reactions. Additionally, CTAB optimizes key physicochemical parameters of the electrolyte, enhancing the stability of the electrode/electrolyte interface and promoting reversibility in AZIBs. Theoretical simulations combined with operando synchrotron radiation‐based in situ Fourier transform infrared spectra and in situ electrochemical impedance spectra further confirm the modified Zn2+ coordination environment and the adsorption effect of CTAB cations at the anode/electrolyte interface. As a result, the assembled Zn‐MnO2 battery demonstrates a remarkable specific capacity of 126.56 mAh g−1 at a high current density of 4 A g−1 after 1000 cycles. This work highlights the potential of CTAB as a promising solution for improving the performance and practicality of AZIBs for large‐scale energy storage applications.

The Formation Analysis of Ca (II), Mg (II), Zn (II) and 5-Hydroxysalicylic Acid Binary Complexes in Cetyltrimethylammonium Bromide Cationic Micelles

The Formation Analysis of Ca (II), Mg (II), Zn (II) and 5-Hydroxysalicylic Acid Binary Complexes in Cetyltrimethylammonium Bromide Cationic Micelles

Enabling high rate capability and stability all-solid-state batteries via cationic surfactant modification of composite electrolyte

The garnet-type solid electrolyte Li6.4La3Zr1.4Ta0.6O12 (LLZTO) was modified with a cationic surfactant Cetyltrimethylammonium Bromide (CTAB) to improve the dispersion of LLZTO inorganic particles in Poly (ethylene oxide) (PEO) electrolyte (PEO-LLZTO@CTAB) by a liquid phase casting method. During fabrication, the cationic modifier CTAB is uniformly adsorbed on the surface of LLZTO particles, which can effectively reduce their surface energy and lead to a thin CTAB surface coating layer. This fabricated PEO-LLZTO@CTAB can avoid the aggregation of LLZTO particles in the composite solid-state electrolyte (CSSE) and improve the interfacial contact at the PEO/LLZTO interface, thus reducing the overall resistance of PEO-LLZTO@CTAB/Li half-cell and inhibiting the dendrite growth during cycling. The all-solid-state batteries (ASSBs) with LiFePO4 (LFP) as the cathode, PEO-LLZTO@CTAB as the electrolyte and Li as the anode exhibit a high initial discharge capacity of 146.6 mAh-g−1, excellent rate performance and high-capacity retention of 91.0 % after 300 cycles at 0.2 C multiplier and 60 °C within the voltage range of 2.7–4.0 V.

Exploring the pH-Responsive Interaction of β-Blocker Drug Propranolol with Biomimetic Micellar Media: Fluorescence and Electronic Absorption Studies.

Interaction of neutral and charged lipophilic beta-blocker drug, propranolol (PPL) with biomimicking nanocavities formed by micelles bearing same and opposite charges namely, cationic cetyltrimethylammonium bromide (CTAB), a surface-active ionic liquid 1-hexadecyl-3-methylimidazolium chloride (HDMIC) and anionic sodium dodecyl sulphate (SDS) have been investigated using fluorescence and absorption spectroscopic techniques. Binding of PPL to SDS at pH < pKa is characterised by biphasic interactions with decrease in fluorescence intensity at lower concentrations and subsequent increase post micellization. All the surfactants show significant interactions with the neutral drug molecule at pH > pKa, which is evident from the strongest binding constant ( ) values at pH 10.4. Results of quenching studies indicate that the location of drug molecule is determined by its charge, which is influenced by both pH and charge on micelle surface. For PPL-CTAB and PPL-HDMIC systems, quenching was strongest at pH 10.4, moderate at pH 7.4 and was absent at pH 3.5. However, the PPL-SDS system displayed similar values at all pH conditions, suggesting that the probe is at the same position regardless of pH. Non-covalent interactions, which play crucial role in biological systems, are similarly the primary driving force governing the interaction between PPL and surfactant micelles.

Thermodynamics of modulation of interaction of α-helix inducer 2, 2, 2-trifluoroethanol with lysozyme in presence of cationic, anionic and non-ionic surfactants

The interactions of anionic sodium dodecyl sulphate (SDS), cationic cetyltrimethylammonium bromide (CTAB) and nonionic triton X-100 (TX-100) surfactants with lysozyme at pH = 2.4 have been studied individually as well as in combination with 2,2,2-trifluoroetanol (TFE). Urea has also been used in combination with surfactants. By using these combinations, efforts have been made to obtain partially folded conformations of the protein in the presence of surfactants and effect of α-helix inducer 2,2,2-trifluoroethanol on these intermediate states. Thermodynamic analysis of all these interactions has been done employing a combination of UV-visible, fluorescence and circular dichroism spectroscopies. The results have been correlated with each other and characterized qualitatively as well as quantitatively. At lower concentration of surfactant, the thermodynamic parameters indicated the destabilizing effect of SDS, stabilizing effect of CTAB and unappreciable destabilizing impact of TX-100 on lysozyme. The enhancement in destabilization effect or reduction in stabilization effect of surfactants on lysozyme in the presence of TFE and urea has also been indicated. Communicated by Ramaswamy H. Sarma

Transport of polystyrene nanoplastics in porous media: Combined effects of two co-existing substances

Both surfactants and natural organic matters (NOMs) are substances commonly found in aqueous environments, and their effects on the transport of nanoplastics that is gradually gaining widespread attention in porous media are currently in their infancy, while their combined effects are absent. We investigated innovatively the combined effect of surfactants and NOMs on the transport of polystyrene nanoplastics (PS-NPs) in saturated porous media. Adsorption tests of surfactants and NOMs onto PS-NPs, adsorption tests of PS-NPs onto quartz sand, and transport tests of PS-NPs in saturated quartz sand were conducted. Hydrophobicity and Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energy were measured and calculated. A mathematical model was employed to fit the transport of PS-NPs in porous media. It was found that the effects and action mechanisms of cationic cetyl trimethylammonium bromide (CTAB) and anionic sodium dodecylbenzene sulfonate (SDBS) on the transport of PS-NPs in porous media were distinct. In the presence of CTAB, 1 mg/L humic acid (HA) and 10 mg/L sodium alginate (SA) could promote aggregation of PS-NPs by decreasing the absolute zeta potential of PS-NPs, and reducing the energy barrier between PS-NPs and porous media and increasing the blocking and straining, thus inhibiting the transport of PS-NPs. In the presence of SDBS, SA and HA could improve the adsorption of SDBS onto PS-NPs by bridging and increasing adsorption sites, thus increasing the hydrophilicity of PS-NPs and improving the transport of PS-NPs. Whether or not NOMs were present, the transport of PS-NPs in porous media was mainly governed by the DLVO interaction energy in the presence of cationic surfactants and by hydrophobicity in the presence of anionic surfactants. This innovative observation has led to an understanding on the environmental behaviour of nanoplastics in porous media under complex environments.

Enhanced electronic absorption and solubility of Mammeigin in aqueous micelles and protein aggregate solutions compared to water

The physicochemical properties of plant polyphenol Mammeigin (MMG) from Mesua ferrea, upon interactions with carrier molecules like surfactants and Hen Egg-White Lysozyme (HEWL) aggregates were investigated using UV–Vis and Fluorescence spectroscopy; and Zeta potential (ZP) measurements in aqueous solutions. The role of surfactant charge on the interactions of MMG was studied using anionic Sodium Dodecyl Sulfate (SDS), cationic Cetyltrimethylammonium Bromide (CTAB), and neutral Tween 20 (T20). It was observed that ionic surfactants offered more stability to the system, which was enhanced in the presence of salt at physiological concentration and lower amounts of surfactant. The environment of MMG in these micelles was proposed to be partially semi-polar in nature based on solvent studies in organic and binary solvent systems. A similar favorable environment was found in early and partially exposed aggregates of HEWL at pH 2 and pH 9 respectively, which significantly diminished at later stages of aggregation and fibrillation at pH 2. With growing interest in plant polyphenols as bioactive, a major challenge for their utility in biological systems is the aqueous insolubility and thus, research in the field of drug/compound delivery is expanding. Our study could provide insights for developing better molecular carriers and formulations of MMG at physiological conditions for therapeutic applications with improved efficacy.

Effects of anionic and cationic surfactants on the surface Plasmon resonance intensity of biogenic silver nanoparticles: Stability, and position of optical band

Fabrication of noble metal nanoparticles by using green plant extract as reducing agent have been the subject of various investigators due to their enhanced plasmonic properties for various applications. This paper describes the effects of cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfate (SDS) on the nucleation of silver sols formation by using coriander seeds extract and silver nitrate redox reaction. The wavelength maxima (λmax) were blue shifted from 433 nm to 425, 423, and 420 nm, respectively, with 0.0, 0.4, 1.0, and 1.6 mM CTAB. The blue and red shifts were also observed from 433 nm to 421, 421, 418, and 438 with 0.0, 0.4, 1.0, 1.6 and 2.0 mM SDS, respectively. The pre-micellar inhibition, and post-micellar catalytic effects were observed on the formation of silver sols with cationic CTAB surfactant. SDS exhibits inhibitory effect on the nucleation rate for an entire range of concentration. Additionally, antioxidant activity in vitro revealed that the percentage scavenging with 2,2-diphenyl-1-picrylhydrazyl (DPPH•) were depended on the dose of AgNPs.

Activation of persulfate by heat, FeNPs, and Fe/MnO2 for the advanced oxidation processes

In this work, we used only persulfate (S2O82−), Fe0/S2O82−, Fe/MnO2/S2O82− systems as an activator to generate reactive radical species for the chemical oxidation of Congo red azo dye. The formation of a new colored species at 363 nm and its decomposition was observed at a specific reaction condition for the first time. Congo red-S2O82− redox reaction was very slow at 22 °C. After the addition of small amount of Fe/MnO2, the red color was decolorized completely within 6 min. The maximum degradation of Congo red was achieved at optimum parametric values of [S2O82−] = 0.2 mM, [Congo red] = 0.6 mM, amount of Fe/MnO2 = 10 mg, pH = 6.5, and temperature = 22 °C. The presence of MnO2 accelerates the generation of sulfate radicals (SO4−•) during the Fenton- like reaction between Fe/MnO2 and S2O82− due to the synergistic effect. The activation energy was found to be 40.1, 48.0, and 92.2 kJ/mol for Fe/MnO2/S2O82−, Fe/S2O82−, and only S2O82−, respectively. The oxidation of Congo red follows complex order kinetics with respect to pH as well as concentrations of S2O82−. Chemical probes experiments with various radical scavengers such as ethanol, tertiary butyl alcohol (TBA), and potassium iodide showed that the SO4−• radicals participate effectively in situ chemical oxidation of Congo red. Cationic cetyltrimethylammonium bromide (CTAB) retarded the persulfate activation by Fe/MnO2 significantly. The morphology of Fe/MnO2 was determined by XRD, EDX, FTIR, SEM, and TEM.

Effect of dispersants on the stability of calcite in non-polar solutions

The surface modification of calcite has been widely used to improve the compatibility of calcite with non-polar solutions, but this method is complex, time-consuming and uneconomical. Thus, we propose to use dispersants for improving the compatibility of calcite with non-polar solutions and systematically study the dispersion effect and mechanism of various dispersants. Anionic bis (2-ethylhexyl) sulfosuccinate sodium (AOT), non-ionic sorbitol monooleate sodium (Span 80) and sorbitol trioleate (Span 85), cationic cetyltrimethylammonium bromide (CTAB), oleic acid (OA) and stearic acid (SA), are used to change the surface properties of calcite in nonpolar solutions. The results of sedimentation and rheology showed that the anionic dispersant AOT had the best dispersion performance and efficiency. All dispersants, except CTAB, can significantly improve the wettability of particle surface, and the calcite adsorbed AOT has the best hydrophobicity. XRD results showed that all dispersants were adsorbed on the surface of calcite. FT-IR and XPS confirmed that AOT adsorbed on the particle surface through the coordination between AOT and Ca2+. Zeta potential shows that the calcite system with anionic AOT has the highest surface charges, indicating that the strong electrostatic interaction is one reason of the stabilization of calcite particles. This work has guiding implications for the selection of dispersants to improve the compatibility of calcite with non-polar solvents.

Application of micellar liquid chromatography to model ecotoxicity of pesticides. Comparison with immobilized artificial membrane chromatography and n-octanol-water partitioning

The potential of Micellar Liquid Chromatography (MLC) to model ecotoxicological endpoints for a series of pesticides was investigated. To exploit the flexibility in MLC conditions, different surfactants were employed and retention mechanism was tracked and compared to Immobilized Artificial Membrane (IAM) chromatographic retention and n-octanol- water partitioning, logP. Neutral polyoxyethylene (23) lauryl ether (Brij-35), anionic sodium dodecyl sulfate (SDS) and cationic cetyltrimethylammonium bromide (CTAB) were used in presence of PBS at pH=7.40 and acetonitrile as organic modifier when necessary. Similarities/ dissimilarities between MLC retention and IAM or logP were investigated by Principal Component Analysis (PCA) and Liner Solvation Energy Relationships (LSER). LSER revealed that hydrogen bonding acidity is the most important factor for differentiation between MLC and IAM or logP. The impact of hydrogen bonding is exemplified in the relationships of MLC retention factors with IAM or logP, which necessitate the inclusion of a relevant descriptor. PCA further revealed that MLC retention factors are clustered together with IAM indices and logP within a broader ellipse formed by ecotoxicological endpoints, involving LC50/ EC50 values of six aquatic organisms namely Rainbow Trout, Fathead Minnow, Bluegill Sunfish, Sheepshead Minnow, Eastern Oyster and Water Flea as well as LD50 values of Honey Bee, thus justifying their use to construct relevant models. Satisfactory specific models for individual organisms, as well as general fish models, were obtained, in most cases, upon combination of MLC retention factors with Molecular Weight (MW) or/ and hydrogen bond parameters. All models were evaluated and compared to previously reported IAM and logP based models using an external validation data set. Predictions with Brij-35 and SDS based models were comparable, although slightly inferior than those obtained with IAM, while they were in all cases better than those obtained with logP. CTAB led to a satisfactory prediction model for Honey Bee, but it was found less suitable for aquatic organisms.

Toxicity of Different Types of Surfactants via Cellular and Enzymatic Assay Systems.

Surfactants have a widespread occurrence, not only as household detergents, but also in their application in industry and medicine. There are numerous bioassays for assessing surfactant toxicity, but investigations of their impact on biological systems at the molecular level are still needed. In this paper, luminous marine bacteria and their coupled NAD(P)H:FMN-oxidoreductase + luciferase (Red + Luc) enzyme system was applied to examine the effects of different types of surfactants, including cationic cetyltrimethylammonium bromide (CTAB), non-ionic polyoxyethylene 20 sorbitan monooleate (Tween 80) and anionic sodium lauryl sulfate (SLS), and to assess whether the Red + Luc enzyme system can be used as a more sensitive indicator of toxicity. It was shown that the greatest inhibitory effect of the surfactants on the activity of luminous bacteria and the Red + Luc enzyme system was in the presence of SLS samples. The calculated IC50 and EC50 values of SLS were 10-5 M and 10-2 M for the enzymatic and cellular assay systems, respectively. The results highlight the benefits of using the enzymatic assay system in ecotoxicology as a tool for revealing surfactant effects on intracellular proteins if the cellular membrane is damaged under a long-term exposure period in the presence of the surfactants. For this purpose, the bioluminescent enzyme-inhibition-based assay could be used as an advanced research tool for the evaluation of surfactant toxicity at the molecular level of living organisms due to its technical simplicity and rapid response time.

Effect of Surfactants on the Binding Properties of a Molecularly Imprinted Polymer.

In molecularly imprinted polymers, non-specific interactions are generally based on weak forces between the polymer surface and the sample matrix. Thus, additives able to interfere with such interactions should be able to significantly reduce any non-specific binding effect. Surfactants represent an interesting class of substances as they are cheap and easily available. Here, we present a study of the effect of three surfactants (the anionic sodium dodecylsulphate, SDS, the cationic cetyltrimethylammonium bromide (CTAB) and the non-ionic polyoxyethylene-(20)-sorbitan monolaurate Tween 20) on the binding affinity of a 2,4,5-trichlorophenoxyacetic acid (2,4,5-T)-imprinted polymer for the template and its analogue 2,4-dichlorophenoxyacetic acid (2,4-D). The experimental results indicate that increasing amounts of surfactant decrease the binding affinity for the ligands strongly for the ionic ones, and more weakly for the non-ionic one. This effect is general, as it occurs for both 2,4,5-T and 2,4-D and for both the imprinted and the not-imprinted polymers. It also proves that the magnitude of this effect mainly depends on the presence or absence of an ionic charge, and that the hydrophobic "tail" of surfactants plays only a minor role.

Efficient extraction of phenol from wastewater by ionic micro-emulsion method: Anionic and cationic

Phenolic wastewater is one of the priorities in the field of wastewater treatment, which poses a serious threat to the human health and nature environment. In this paper, cationic cetyltrimethylammonium bromide (CTAB) and anionic sodium oleate (NaOL) microemulsions were utilized to extract phenol from the wastewater. The optimal extraction factors were investigated by exploring the effects of microemulsion composition ratio and extraction conditions on the phenol extraction performance. Furthermore, the enhanced extraction mechanism of phenol by cations microemulsions is illustrated by studying the extraction process of cationic and anionic microemulsions in the extraction of phenol. The optimum components were obtained: surfactant concentration of 0.2 mol·L–1, isoamyl alcohol volume of 30%, internal aqueous phase concentration of CTAB microemulsion of 0.05 mol·L–1, and internal aqueous phase concentration of NaOL microemulsion of 0.09 mol·L–1. The extraction efficiencies were 96.44% and 82.0% when using CTAB and NaOL microemulsions under optimal conditions (water–emulsion ratio of 5, contact time of 9 min, extraction temperature of 298.15 K, and pH of 9), confirming the enhanced extraction of phenol by CTAB cationic microemulsion. It was analyzed that the enhanced extraction of CTAB microemulsion was due to the electrostatic adsorption of cations with phenol root ions.