Nonionic TX-100 Research Articles

Integration of the partition effect into the model of non-aqueous phase liquid solubilization by non-ionic surfactant.

Accurately predicting the efficiency of surfactant-enhanced recovery of non-aqueous phase liquid (NAPL) using non-ionic surfactants requires a precise estimation of the kinetics of rate-limited solubilization under the effect of bulk partition. This study investigated the kinetics of surfactant partition from aqueous phase into liquid NAPL and its subsequent impact on the solubilization kinetics of dodecane. For all surfactants examined, the solubilization of dodecane by anionic rhamnolipid (RL) and SDBS, presenting NAPL-water interface adsorption loss only, closely followed the first-order mass transfer model under the assumption of constant solubility. In contrast, the solubilization of dodecane by non-ionic TX-100 showed significant deviations due to the progressive partition of TX-100 into the bulk of liquid dodecane. The first-order mass transfer model, based on the physical hypothesis of the two-film model, accurately depicted the dynamic partition loss of TX-100. The accuracy of the first-order mass transfer model in depicting the dynamic solubilization kinetics of dodecane by TX-100 was improved by setting the equilibrium solubility as variable to account for the effect of the bulk partition loss. The findings quantified the capability of surfactants to solubilize NAPL with considering the impact of bulk partition loss, providing insights into the fundamental processes of NAPL solubilization with the application of non-ionic surfactants.

Physicochemical investigations of interaction of antitumor etoposide with ionic and nonionic micelles: a spectroscopic, conductivity and voltammetric study

This work aims to comprehend the physicochemical interaction of etoposide (trade name “VP-16”) with biological membranes using biomembrane models. Surfactants, owing to their remarkable chemical similarity with biomembranes, can be used to simulate the interactions and behavior of VP-16 in biological systems. The present study explores the physicochemical interactions of chemopreventive VP-16 with ionic dodecyltrimethylammonium bromide (DTAB), sodium dodecyl sulfate (SDS), and nonionic TX-100 & Tween-80 surfactants at the molecular level using different techniques. UV-visible spectroscopy results at 298.15 K indicate that both hydrophilic and hydrophobic interactions significantly influence the solubility of the drug in micellar systems. According to the estimated partition coefficient (Kx ) and binding constant (Kb ) obtained from the differential mode of the UV-Vis, VP-16 exhibits better binding and partitioning with nonionic surfactants compared to ionic surfactants. Thermodynamic parameters ( Δ H m o , Δ S m o , & Δ G m o ) are computed from 298.15 K to 318.15 K with a temperature interval of 5 K using conductivity data. The positive values of Δ H m o and Δ S m o and the negative values of Δ G m o indicate the disruption of water structure during the micellization process in the presence of VP-16 and the spontaneous transport of drug molecules into micelles, respectively. Voltammetric data at 298.15 K show that DTAB and TX-100 favor the oxidation of VP-16. This kind of study may be used to modify currently available drugs, design new chemotherapeutics, and formulate effective drug delivery systems to boost the drugs bioavailability.

The role of titanium dioxide surface modification on UV protective properties of eco-friendly PA coating

The aim of this work is to prepare polyacrylate emulsions (PA) with the addition of modified titanium dioxide (TiO2) nanoparticles. The modifiers used in this work are the nonionic emulsifier TX-100, the cationic initiator AIBA, the silane AMPTS, and the trisilanol POSS. The results show that particles with a larger hydrodynamic diameter are formed by the addition of modified fillers and that the viscosity of the PA emulsion increases significantly due to the modification of the TiO2 surface. The morphology indicates poorer dispersibility and distribution of the modified fillers in the polymer compared to coating with unmodified fillers. The thermal stability of PA is significantly increased by the addition of modified TiO2 nanoparticles. The results have also shown that the modification of TiO2 with AMPTS increases the UV absorbing ability of TiO2, while the modification with other modifiers enhances the photocatalytic effect of TiO2.

The effect of nanosilica sizes in the presence of nonionic TX100 surfactant on CO2 foam flooding

The aim of this research is to study the effect of hydrophilic silica nanoparticles, sizes as CO2 foam stabilizer in the presence of nonionic TX100 surfactant. Two nanosilica sizes, 15 and 70 nm, have been examined thoroughly. Physisorption of TX100 on silica nanoparticles (nanosilica) was characterized by adsorption isotherm and surface tension measurement, while CO2 foams stability was quantified based on their foamability, foam stability, particle partitioning in the foams, and bubble sizes. Results show that direct contact of TX100 with nanosilica does altered the wettability of hydrophilic nanosilica surface, enable them to lengthen CO2 foams life at certain surfactant and nanoparticles concentrations. For 15 nm nanosilica, CO2 foam stability shows excellent performance at 0.1 and 0.5 wt% TX100 concentrations. As for 70 nm nanosilica, CO2 foam demonstrates longer lifetime at much lower TX100 concentration, 0.01 wt%. Without the presence of TX100, CO2 foams exhibit undesirable lifetime performances for both nanosilica sizes. Nanosilica partitioning in CO2 foams structures demonstrate consistent relation with contact angle measurement. Estimated bubble sizes shows insignificant effect on CO2 foams life. With the assists of nanosilica and TX100, enhanced oil recovery via CO2 foam injection succeeds in increasing oil production by 13–22% of original oil-in-place (OOIP).

Effects of Different Surfactant Charges on the Formation of Gold Nanoparticles by the LASiS Method.

The laser ablation synthesis in solution (LASiS) method has been widely utilized due to its significant prospects in laser microprocessing of nanomaterials. In this study, the LASiS method with the addition of different surfactant charges (cationic CTAB, nonionic TX-100, and anionic SDS) was used to produce Au NPs. An Nd:YAG laser system at 532 nm excitation with some synthetic parameters, including different laser fluences, ablation times, and surfactant concentrations was performed. The obtained Au NPs were characterized by UV-Vis spectroscopy, transmission electron microscopy, and zeta potential analyzer. The Au NPs exhibited the maximum absorption peak at around 520 nm for all samples. The color of Au NPs was changed from red to reddish by increasing the laser fluence. The surfactant charges also played different roles in the Au NPs’ growth during the synthesis process. The average sizes of Au NPs were found to be 8.5 nm, 5.5 nm, and 15.5 nm with the medium containing CTAB, TX-100, and SDS, respectively. Besides, the different surfactant charges induced different performances to protect Au NPs from agglomeration. Overall, the SDS and CTAB surfactants exhibited higher stability of the Au NPs compared to the Au NPs with TX-100 surfactant.

Temperature dependence on the size control of palladium nanoparticles by chemical reduction in nonionic surfactant/ionic liquid hybrid systems

Metal nanoparticles of palladium (Pd) were synthesized by the chemical reduction of palladium acetylacetonate (Pd (acac)2) dissolved in room-temperature ionic liquids (ILs) containing various nonionic Brij series surfactants (such as Brij-30, Brij-52, Brij-56, Brij-58, Brij-35, and Brij-700) and TX-100. The obtained self-assembled structure of Pd nanoparticles in the surfactant/IL hybrid systems without any cosurfactant/cosolvent was investigated using in situ small-angle X-ray scattering measurements and cryo transmission electron microscopy observations. Size control of Pd nanoparticles was accomplished by simply adjusting the reaction temperature to around 433 K and choosing the surfactant. Brij-58 and Brij-35 were the most appropriate of our experimental conditions for the formation of a stable surfactant/IL hybrid system containing Pd nanoparticles. The most efficient method to regulate Pd nanoparticle size was a temperature-controlled gradual synthesis whereby the reaction temperature for the reduction of Pd (II) ions was increased stepwise from 333 K to 433 K over approximately 60 min. Furthermore, the detailed formation mechanisms of the self-assembled structure of Pd nanoparticles in surfactant/IL hybrid systems were shown using in situ and time-resolved small-angle X-ray scattering measurements.

Effects of surfactants on the removal of nitrobenzene by Fe(II) sorbed on goethite

Surfactants are easily accumulated in groundwater, sediment, and aquifers, due to their excessive use in household, industrial, and agricultural processes. These residual surfactants are expected to influence the transformation and fate of organic contaminants by Fe(II) sorbed on iron oxides in anaerobic environments. Here, we investigated the effects of various surfactants including nonionic TX-100, anionic SDBS and bio-surfactant saponin on the removal of nitrobenzene (NB) by Fe(II) sorbed on goethite (goethite/Fe(II)) through batch experiments. We also elucidated the mechanism behind the effects by XPS, XRD, and determination of the amounts of sorbed Fe(II) on goethite. The results showed that the presence of TX-100 improved NB removal from 77.2% in the absence of surfactant, to 93.8% within 6 h, and improved the removal rate by about 1.3 times. In contrast, the presence of SDBS decreased the removal efficiency to 45.5%, and the presence of saponin nearly inhibited the removal of NB completely. The removed NB was finally nearly reduced to aniline in the absence or presence of surfactants, except in the case of saponin. The amounts of sorbed Fe(II) listed in the sequence as goethite/Fe(II)+TX-100 > goethite/Fe(II) > goethite/Fe(II)+SDBS > goethite/Fe(II)+saponin, and this order negatively correlated with that in the redox potential of these systems. These results confirmed that the presence of surfactants influenced the sorption of Fe(II) on goethite and changed the reactivity of goethite/Fe(II) for NB removal. This finding will promote a clear understanding of the impact of coexisting surfactants on the transformation and fate of organic contaminants in real anaerobic environments.

Quantifying the effect of solution formulation on the removal of soft solid food deposits from stainless steel substrates

The role of detergent formulation on the cleaning of a complex carbohydrate-fat food soil from stainless steel surfaces was studied using a modified version of the millimanipulation device described by Ali et al. (2015b) which allowed the force required to scrape the soil from the surface to be measured as the soil is immersed, in situ and in real time. This allowed the influence of temperature, solution chemistry and time on the mechanical forces (rheology) and removal behaviour of the soil to be studied – in effect quantifying the relationships in Sinner's cleaning circle. The soil simulated a burnt-on baked-on deposit and featured regular cracking in the 300 μm thick layer. The removal force decreased noticeably on hydration: the cleaning mechanism was then determined by the agents present. At 20 °C, below the temperature at which the fat phase was mobile, removal was characterised by cohesive failure except in the presence of the cationic surfactant CTAB, which promoted adhesive failure and fast decay in removal force. At 50 °C, when the fat was mobile, a transition between cohesive and adhesive failure was observed at pH 7 which was inhibited at higher pH. Adhesive failure and fast decay in removal force was observed at higher pH and 50 °C in the presence of the anionic and non-ionic surfactants, SDBS and TX-100, respectively.

Competitive partitioning of phenanthrene in carbon nanomaterials and anionic and nonionic micelles

Presence of carbon nanomaterials in the environment can significantly impact the removal of polycyclic aromatic hydrocarbons by surfactant-enhanced remediation. The aim of this study was to investigate the impact that carbon nanomaterials have on surfactant remediation, which was done by analyzing the partitioning of phenanthrene, a model polycyclic aromatic hydrocarbon, in mixed carbon nanomaterials (carbon nanotubes and graphene) and surfactant (anionic SDBS and nonionic TX-100) solutions via batch solubilization and adsorption experiments. The presence of carbon nanomaterials was found to suppress phenanthrene solubilization as it absorbed both phenanthrene and surfactants; decreasing the amount of surfactants further lowered phenanthrene solubilization. Compared with SDBS, TX-100 showed a greater ability to solubilize phenanthrene in the presence of carbon nanomaterials. The adsorption of phenanthrene to carbon nanomaterials was suppressed with TX-100, demonstrating competitive adsorption between TX-100 and phenanthrene. Conversely, with SDBS present, the adsorption of phenanthrene to carbon nanomaterials increased, showing complementary adsorption between SDBS and phenanthrene; the maximum amount of phenanthrene adsorbed to both graphenes and carbon nanotubes was approximately 170 mg/g with SDBS present, compared to 122.8 and 95 mg/g without SDBS, respectively. The contrasting effects of TX-100 and SDBS on the distribution of phenanthrene was explained as follows: a) SDBS is less able to solubilize phenanthrene, b) carbon nanomaterials have high adsorption affinity for SDBS, and c) phenanthrene can be absorbed by SDBS. Overall, these findings demonstrate the mechanisms for the impact of carbon nanomaterials on phenanthrene partitioning in anionic (SDBS) and nonionic (TX-100) surfactants.

Alkaline Hydrolysis of Methyl Decanoate in Surfactant-Based Systems.

Surfactant-modified reaction systems are one approach to perform organic reactions with water as the solvent involving hydrophobic reactants. Herein, the alkaline hydrolysis of the long-chain methyl decanoate in cationic and nonionic surfactant-modified systems is reported. The physicochemical behavior of the reaction mixture and the performance of the alkaline hydrolysis were systematically investigated. In water as the solvent, the reaction is slow, but at elevated temperatures, the alkaline hydrolysis of methyl decanoate is accelerated because the reaction product sodium decanoate acts as an ionic surfactant, leading to an increased solubility of methyl decanoate in the aqueous phase. The rate can be significantly increased by the addition of surfactants as solubilizers. In nonionic TX-100 solutions, the reaction rate can be increased by a factor of about 100 for a surfactant concentration of 5 wt %. If cationic surfactants are applied, the reaction rate can be further increased due to the electrostatic interaction between the hydroxide ions in solution and the charged head groups of the cationic micelles.

Quinolinium bound chromium(VI) reagents for efficient electrophilic aromatic nitration and thiocyanation reactions using sodium nitrate and ammonium thiocyanate

Quinolinium dichromate (QDC) and quinolinium chlorochromate (QCC) were studied as efficient reagents for electrophilic aromatic nitration using sodium nitrite and thiocyanation by using ammonium thiocyanate under conventional, ultrasonic and solvent-free microwave assisted conditions. The microwave-assisted protocols exhibited remarkable rate acceleration and offered selective thiocyanation of the aromatic and heteroaromatic compounds with good yields. Addition of anionic (SDS) micelle to the reaction medium afforded considerable rate enhancements, while cationic (CTAB) and nonionic (Tx-100) micelles did not affect the rate noticeably. These protocols have were extended to regioselective thiocyanation of various aromatic compounds. Results were are completely similar to the nitration protocols. However, the reactions revealed comparatively shorter reaction times, and better yields in nitration reactions than in thiocyanation protocols. Catalytic effect of the SDS was attributed to the electrostatic stabilization of the cationic electrophile (NO2+ in nitration, and SCN+ in thiocyanation).

Dyeing properties of CI reactive violet 2 on cotton fabric in non-ionic TX-100/Span40 mixed reverse micelles

In order to improve the dyeing properties of reactive dyes onto cotton fabric in reverse micelles, non-ionic mixed reverse micelles were prepared using non-ionic TX-100 and Span40 as a dyeing media. The maximum water solubilization, diameter of water pool, aggregation density, and conductivity values of the reverse micelles with different concentrations of TX-100/span40 were measured and compared. The adsorption and dyeing capacity of reactive dyes on cotton fabric in reverse micelles were investigated. Additionally, the Lagergren first-order equation and the pseudo second-order equation were also employed to fit the experimental data. The results indicated that the diameter of water pool and packing density of reverse micelles were increased with an increasing amount of Span40, which caused lower conductivity. The repelling force and competitive adsorption between the dyes and cotton fabric were decreased with an increasing amount of Span40, and the higher adsorption and improved dyeing properties in reverse micelles were obtained. Moreover, the dye adsorption process in mixed TX-100/Span40 reverse micelles could be described using pseudo-second-order kinetic equations. The adsorption is a chemical process.

Investigations on zwitterionic alkylsulfobetaines and nonionic triton X-100 in mixed aqueous solutions: Effect on size, phase separation and mixed micellar characteristics

Zwitterionic sulfobetaine surfactants are widely applied in industries dealing with personal care products, mainly due to an advantage of minimal irritating effects to skin as compared to ionic surfactants. We investigate on the aqueous solution behaviour of zwitterionic surfactant, namely alkyl N,N-dimethyl-3-ammonio-1-propanesulfonate (CnPS, n=10, 12, 14, 16) in pure and mixed state with Triton X-100 (non-ionic surfactant) by using surface tensiometry, dynamic light scattering (DLS) and cloud point measurements. The critical micelle concentration (CMC) for aqueous CnPS solutions decreases with corresponding increase in alkyl chain length and is also accompanied by an increase in aggregation number. The calculated interfacial parameters for binary mixed aqueous systems involving zwitterionic surfactant and TX-100 depict almost independent behaviour of πCMC and Γmax, indicating a non-associative ideal mixing. The calculated interaction parameter (βm) for TX-100+CnPS mixed system reveals insignificant deviation from ideal behaviour as confirmed by calculated values in proximity to zero. As concluded from size measurements using DLS, the apparent hydrodynamic size of the mixed micelles decreases with gradual addition of alkylsulfobetaines due to demicellization of formerly present ellipsoidal aggregates of TX-100. The clouding temperature of formed mixed micelles increases on gradual addition of CnPS due to corresponding increase of ionic charge and accordingly improved solubility. It is assumed that electrically neutral nature of sulfobetaines confines its electrostatic interactions with non-ionic TX-100 and accordingly deters feasible interactions leading to synergism.

Micellar-enhanced ultrafiltration for the solubilization of various phenolic compounds with different surfactants.

Micellar-enhanced ultrafiltration (MEUF) was applied to the separation of phenolic compounds p-nitrophenol (PNP), p-chlorophenol (PCP), p-cresol (PC) and phenol (P) from effluents using a hydrophilic polyethersulfone ultrafiltration membrane. Cationic cetylpyridinium chloride (CPC), nonionic TX-100 and anionic sodium dodecyl benzene sulfonate (SDBS) were chosen as the surfactants. Several important parameters, i.e. the separation efficiency, the distribution coefficient of phenolic compounds and the removal ratio of surfactants, were investigated. It was shown that the separation efficiency and the distribution coefficient of phenolic compounds ascended with the increasing surfactant concentration and could be arranged as the following order: PNP>PCP>PC>P. Moreover, in the case of phenolic compound separation, CPC achieved the highest treatment efficiency, and the separation efficiency of SDBS was a little lower than that of TX-100. The removal ratios of the same surfactant when treating different phenolic effluents were nearly similar. However, when treating the same phenolic compound, the sequence of the surfactant rejection was in the following order: TX-100>CPC>SDBS. These results indicate that CPC has a distinct superiority in the treatment of phenolic effluents via the MEUF process, and PNP easily solubilizes in the surface of the micelles.

Effect of surfactant type on platinum nanoparticle size of composite Pt/α-Al2O3 catalysts synthesized by a microemulsion method

A facile method for the generation of platinum-on-alumina hybrid materials with high-surface area is presented, employing a microemulsion-based synthesis of metal nanoparticles. Pt nanoparticles (NPs) supported on α-Al2O3 were prepared by the reduction of metal ions in water-in-oil microemulsion systems stabilized by a range of different surfactants with cationic, anionic and nonionic headgroups, namely AOT, CTAB, Tween80 and TX-100. The synthesized materials were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). It is demonstrated that choice of surfactant can be used to tailor the size of the generated Pt nanoparticles, and seen that surfactant charge has a determining role in this process. Pt NPs formed in microemulsion systems based on charged surfactants (AOT and CTAB) are smaller than those prepared in nonionic microemulsion systems (TX-100 and Tween80). A solvent-induced demixing process was used to cleanly obtain the hybrid materials from the reaction medium at low energy cost.

Influence of surfactants on the adsorption and elektrokinetic properties of the system: guar gum/manganese dioxide

The adsorption of non-ionic polysaccharide—guar gum (GG) in the presence or absence of the surfactants: anionic SDS, cationic CTAB, nonionic TX-100 and their equimolar mixtures SDS/TX-100, CTAB/TX-100 from the electrolyte solutions (NaCl, CaCl2) on the manganese dioxide surface (MnO2) was studied. The increase of GG adsorption amount in the presence of surfactants was observed in every measured system. This increase results from formation of complexes between the GG and the surfactant molecules. This observation was confirmed by the determination of the influence of GG on surfactants adsorption on the MnO2 surface. The increase of GG adsorption on MnO2 was the largest in the presence of the surfactant mixtures (CTAB/TX-100; SDS/TX-100) which is the evidence of the synergetic effect. The smallest amounts of adsorption were obtained in the presence of TX-100, which results from non-ionic character of this surface active agent. In the case of single surfactant solution CTAB has the best efficiency in increasing the amount of GG adsorption on MnO2 which results from strong interactions with GG and also with the negatively charged surface of the adsorbent. In order to determine the electrokinetic properties of the system, the surface charge density of MnO2 and the zeta potential measurements were performed in the presence of the GG macromolecules and the above mentioned surfactants and their mixtures. The obtained data showed that the adsorption of GG or GG/surfactants complexes on the manganese dioxide surface strongly influences the diffused part of the electrical double layer (EDL)—MnO2/electrolyte solution, but has no influence on the compact part of the electric double layer. This is the evidence that the polymers chains are directly bonded with the surface of the solid and the surfactants molecules are present in the upper part of the EDL.

Physicochemical and antibacterial properties of surfactant mixtures with quaternized chitosan microgels

Antibacterial surfactant mixtures attract widespread interest in the design of consumer product formulations, but often use toxic biocidal agents such as cationic surfactants, triclosan or bleach. To address this, we explored replacing these toxic ingredients with quaternized chitosan microgels, which combine high antibacterial activity with cytocompatibility with mammalian cells. Specifically, three essential properties of microgel mixtures with model anionic (sodium dodecyl sulfate, SDS) and nonionic (Triton X-100, TX-100) surfactants (and with SDS/TX-100 mixtures) were investigated: (1) colloidal stability, (2) antibacterial activity, and (3) hydrophobe solubilization. Additionally, the effect of surfactant on dispersion turbidity, which can be important in the formulation of aesthetically-appealing products, was explored. The microgels formed more-stable dispersions when mixed with nonionic TX-100, but quickly precipitated when mixed with the electrostatically-binding SDS and SDS/TX-100 surfactant systems at fairly-low (millimolar) surfactant concentrations. At higher SDS concentrations the microgels were redispersed and ultimately dissolved when mixed with only SDS, but remained precipitated in SDS/TX-100 mixtures. Furthermore, the electrostatic binding of SDS to quaternized chitosan diminished its antibacterial activity and (because the SDS-bearing mixtures with strong biocidal activity were limited to low surfactant concentrations) also resulted in limited hydrophobe solubilization. Conversely, microgels mixed with TX-100 maintained their biocidal activity even when the surfactant was in excess, and exhibited good solubilization properties. This suggests that surfactant-based products that use quaternized chitosan microgels as antibacterial agents should optimally be formulated using nonionic surfactants.

Effect of t-octylphenoxylpolyethoxyethanol (TX-100) on the dilute aqueous solution phase diagrams, surface activity and micellization behavior of non-ionic silicone surfactants (SS) in aqueous media

Dilute aqueous solution phase diagrams, surface tension, dynamic light scattering (DLS) and dilute solution viscosity measurements have been made in aqueous solutions of nonionic silicone surfactants (SS) in presence of t-octylphenoxylpolyethoxyethanol (TX-100). Critical micelle concentration, thermodynamic parameters of association, interfacial characteristics such as pC20, surface excess, Γmax , area per adsorbed molecule, a1s along with the size and shape and intrinsic viscosities of the associates have been determined and discussed to ascertain the effect of TX-100 as an additive in SS aqueous solutions. The importance of hydrophobic/hydrophilic (hp/hl) ratio of the SS rather than their molecular architecture and molar mass on their overall interaction with TX-100 micelles has been reflected in the above parameters for the mixture solutions. It was observed that the mixed species in SS aqueous solutions in TX-100 are more hydrophilic in nature and the overall association process in the mixture solutions is entropy driven. TX-100 addition to SS micellar solutions induces the dissociation of SS micelles. As compared to the room temperature, the mixed micelles at elevated temperatures were large in size suggesting that the ellipsoidal micelles in mixed state grow along their major axis that is typically characteristic of the micelles of the individual nonionic SS or TX-100 surfactants at temperatures close to the turbid point.

UV-Visible Spectrometric Study and Micellar Enhanced Ultrafiltration of Alizarin Red S Dye

Ultraviolet spectrometric study of alizarin red S (ARS) showed the substantial change in dye spectra by cationic CTAB as compared to anionic SDS and nonionic TX-100 surfactant. High spectral change by CTAB confirms the anionic nature of ARS dye and thus ARS-CTAB complex formation takes place due to electrostatic force of attraction. A little spectral change by SDS is the result of similarly charged repulsive forces that overcome weak hydrophobic-hydrophobic interaction between dye and surfactant micelles. TX-100 exhibited moderate spectral effect responsive to weak hydrophobic-hydrophobic interaction alone. MEUF study of ARS dye justified the spectral changes and dye rejection percentage (R) decreases in the following order: cationic > nonionic > anionic surfactant. Permeate flux (J) slightly decreases in presence of CTAB and it remains virtually constant for both SDS and TX-100. Addition of copper salt (i.e., CuCl2) in dye-CTAB complex solution, favors rejection (%) removing dye and copper simultaneously via micellar enhanced ultrafiltration.

Kinetics of Reduction of Colloidal MnO2 by Glyphosate in Aqueous and Micellar Media

The kinetics of the reduction of colloidal MnO2 by glyphosate has been investigated spectrophotometrically in an aqueous and micellar (cetyltrimethylammonium bromide, sodium lauryl sulfate) media. The reaction follows first-order kinetics with respect to colloidal MnO2 in both the aqueous and micellar media. The rate of oxidation increases with increase in [glyphosate] in the lower concentration range but becomes independent at its higher concentrations. The addition of both the anionic (NaLS) and cationic (CTAB) micelles increased the rate of reduction of colloidal MnO2 by glyphosate while the nonionic TX-100 micelles did not influence the rate of reaction. In both aqueous and micellar media, the oxidation of glyphosate occurs through its adsorption over colloidal MnO2 surface. The reaction in micellar media was treated by considering the pseudophase model. The values of reaction rates and binding constants in the presence of micelles were determined.