Cetyldimethylethylammonium Bromide Research Articles

Removal of Surfactant Cetyldimethylethyl Ammonium Bromide from Water using Adsorption in Combination with a Membrane Pilot Plant

Abstract In this study, a magnetic carbon nanocomposite (MCNC) was prepared using peanut shell biomass as carbon source. The prepared adsorbent was characterised by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric/differential thermal analysis (TGA/DTA) and BET surface analysis. Batch experiments were carried out to determine the adsorption parameters of cetyl dimethylethyl ammonium bromide (CDEAB) on MCNC. Of the isotherm and kinetics models used, the Langmuir model fitted the equilibrium adsorption data best, while the kinetics data were best explained by the second-order kinetic pseudo-equation. The numerical values of enthalpy change (ΔH8 = 38 kJ mol–1) and Gibb free energy (ΔG8 = 70.95 kJ mol–1, 72.19 kJ mol–1 and 73.32 kJ mol–1 corresponding to 20°C, 30°C and 40 °C, respectively) were positive, while the value of entropy change (ΔS8 = –0.11 kJ mol–1 K–1) indicated an endothermic and non-spontaneous process. After determining the optimal adsorption parameters, the adsorbent was used in a hybrid plant with a membrane pilot plant equipped with ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membranes. In MCNC/membrane operation, an improvement in permeate flux was observed for the three selected membranes. The percentage retention of UF and NF membranes was also improved by MCNC pre-treatments in hybrid mode.

Aggregation behavior of cetyldimethylethylammonium bromide under the influence of bovine serum albumin in aqueous/electrolyte solutions at various temperatures and compositions: conductivity and molecular dynamics study.

Herein, we have investigated the interaction of bovine serum albumin (BSA), the most abundant globular protein, with a conventional cationic surfactant, cetyldimethylethylammonium bromide (CDMEAB), through a conductivity technique in the absence/presence of electrolyte solutions at various temperatures (298.15–323.15 K). The interaction of the protein with drugs/surfactants and other additives plays a crucial role in the body. Hence, the main concern of the study is to extract the impact of BSA on surfactant molecules and vice versa. From the specific conductivity versus concentration of surfactant plots, three different noticeable critical micelle concentration (c*) values were obtained for pure CDMEAB and its mixture with protein/protein + salts. The presence of BSA and electrolytes altered the c* values of CDMEAB revealing interactions among the studied constituents where the salt solutions reduced the c* values and created a convenient environment for favorable micellization. The negative magnitudes achieved for standard free energy changes (ΔG0m) suggest spontaneity of micellization while the values of ΔH0m and ΔS0m signified the existence of some electrostatic and hydrophobic interactions. The values of molar heat capacity (ΔC0m) were positive as well as small which was an indication of less structural deformation. Molecular Dynamics (MD) simulation for all atoms revealed that the salt ions promoted non-covalent interaction between BSA and CDMEAB, and such interactions were not observed in the absence of the salt. Protein structure remained nearly same in spite of strong interaction with CDMEAB as evident from the overall RMSD (root-mean-square deviation) values of the alpha carbons and backbone of the protein and RMSF (root-mean-square fluctuation) values of the amino acid residues present in BSA. In this work thermodynamic parameters of transfer (such as ΔG0m.tr., ΔH0m.tr., and ΔC0p.m.tr.) were also evaluated and the results are discussed in detail. Besides, contributions of enthalpy and entropy to free energy changes were also analyzed.

Thermal Characterization and Mesomorphic Properties of Binary Mixture of Two Non-Mesogenic Compounds

The binary mixture of two non-mesogenic compounds, viz., cetyl-dimethyl-ethyl-ammonium bromide (CDEAB) and orthophosphoric acid (H3PO4) exhibits very interesting liquid crystalline smectic phases at large range of concentrations and temperature. The mixture with lower and higher concentrations of CDEAB exhibits SmA, SmE, and SmB phases, sequentially when the specimen is cooled from its isotropic phase. Different liquid crystalline phases observed in the mixture were studied using differential scanning calorimetry (DSC), X-ray, and optical microscopic techniques. The temperature variations of optical anisotropy and electrical conductivity have also been discussed. Helfrich potential and elastic moduli have been estimated in the smectic phase using Helfrich model.

Anisotropic Molecular Orientation of Micellar Nematic Phase in a Binary Mixture of Two Nonmesogenic Compounds

We report the results of our studies on the optical and thermal properties of two nonmesogenic compounds, namely, Cetyl-dimethyl-ethylammonium bromide (CDEAB) and Glacial acetic acid. The mixture exhibits very interesting schilieren texture of micellar nematic phase, SmA, SmC*, and SmE phases, respectively, at different concentrations of CDEAB sequentially when the specimen is cooled from its isotropic phase. The order parameter (S) of the micellar nematic phase is estimated with the help of temperature dependence of optical anisotropy from the measured values refractive index and density data. The temperature variation of order parameter of the experimental curve is very well fitted with the Mayer–Saupe theoretical curve. X-ray studies have been discussed. The formation of above phases has been confirmed by optical and DSC studies.

Interaction of cephradine monohydrate with Cetyldimethylethylammonium Bromide

Interaction of cephradine monohydrate (CDM) with Cetyldimethylethylammonium Bromide (CDMEAB) has been studied by conductance measurements in pure form and in the presence of salts like potassium chloride (KCl) and potassium sulphate (K2SO4) over the temperature range of (298.15 to 318.15)K. From conductivity vs. surfactant concentration plots, two critical micelle concentrations like c1∗ and c1∗ were obtained for (CDM+CDMEAB) systems. The variation of c∗ values of CDMEAB in the presence of CDM is the indication of the interaction between CDM and CDMEAB. For the (CDM+CDMEAB) system, the values of c∗ values are higher in magnitude in contrast to that of pure CDMEAB in water over the range in temperature studied. In aqueous solutions of KCl and K2SO4, the c∗ values are changed with the increase of the concentration of salts and hence the micellization is dependent on salt concentration. The ΔGm0 values were negative and the spontaneity of micellization process is found to be increased with increase of temperature. The values of ΔH1,m0 and ΔS1,m0 indicated that the drug mediated CDMEAB aggregation in water was controlled at lower temperatures while at higher temperatures the aggregation was both enthalpy and entropy controlled. The ΔH2,m0 and ΔS2,m0 values revealed that the micellization in water was both enthalpy and entropy controlled at lower and higher temperatures though the effect of entropy at middle temperature was dominant. The results indicated that binding interactions between CDM and CDMEAB are both electrostatic and hydrophobic in nature while the contribution of hydrophobic interaction is dominant at lower temperatures. In aqueous solution of KCl, The ΔHm0 and ΔSm0 values indicated that the micellization was both enthalpy and entropy controlled at lower temperature while the process was entirely entropy driven at higher temperatures. In case of aqueous K2SO4 solution, the micellization was mostly entropy driven over the range of temperatures studied.The negative molar heat capacity change (ΔmCp0) for micelle formation shows that ΔHm0 comes to be more negative as the temperature rises. The small ΔmCp0 and the overall positive binding entropy indicate slight structural rearrangement of CDMEAB micelle in the course of binding with CDM. The presence of linear correlation between ΔHm0 and ΔSm0 values was perceived in all cases.

Destabilization of sol of aerosil OX-50 in solutions of surfactants. II. Aerosil OX-25 in solutions of cationic and nonionic surfactants

The aggregate stability of the sol of Aerosil OX-50 in solutions of cationic surfactants (SAS) of cetyldimethylethylammonium bromide (CDEAB) and cetyltrimethylammonium bromide (CTAB), as well as nonionic SAS alkylphenyl ethers of ethylene glycol, has been studied. Destabilization of the sol in the solutions of SAS was considered in the terms of the balance of surface forces and with regard to the hydrophobic effects.

Interaction of cefalexin monohydrate with cetyldimethylethylammonium bromide

A study of the interaction of cefalexine monohydrate (CLM) with Cetyldimethylethylammonium Bromide (CDMEAB) has been carried out by conductance measurements in aqueous medium and in aqueous solution of salts over temperature range of 303.15K to 318.15K. From conductivity versus surfactant concentration plots, two critical micelle concentrations c1∗ and c2∗ were obtained for both CDMEAB and CLM–CDMEAB systems in all the cases. The changes of c∗ values of CDMEAB in the presence of CLM is indicative of the interaction between CLM and CDMEAB. For the CLM–CDMEAB system, the values of c1∗ are lower and c2∗ values are higher in magnitude compared to that of pure CDMEAB in water over the range in temperature studied. In aqueous solutions of KCl and K2SO4, the decrease of c∗ values indicates the favour of micellization of CLM–CDMEAB system. The ΔG0m values are negative and the spontaneity of micellization process is found to increase with increase of temperature. The values of ΔH01,m and ΔS01,m indicate that the drug mediated CDMEAB aggregation is both enthalpy and entropy controlled while ΔH02,m and ΔS02,m values indicate entropy driven micellization. The results indicate that binding interactions between CLM and CDMEAB are both electrostatic and hydrophobic in nature while the contribution of hydrophobic interaction is dominant at higher temperature. The linear correlation between ΔH0m and ΔS0m values is observed in all cases.

Influence of Organo-Clay on Mechanical and Thermal Properties of O-Muscovite/PP Layered Silicate Nanocomposite

O-Muscovite/PP Layered Silicate Nanocomposites were prepared via melt compounding using different filler content. Muscovite was organomodified with Cetyldimethylethylammonium bromide (CEDAB). The thermal and mechanical properties of nanocomposites, based on polypropylene (PP) filled by organo-clay (O-Muscovite), were studied in order to clarify the effect of O-Muscovite on the O-Muscovite/PP layered silicate nanocomposites by WAXD, TEM and DSC analyses. XRD indicated that O-Mica layers were intercalated and dispersed into polypropylene. Analysis of test data shows that, addition of organo-clay improved mechanical properties of O-Mica/PP nanocomposites. With the incorporation of 5 wt% O-Mica (optimal filler loading) into polypropylene Izod impact increased to 23%. The DSC analyses have shown that the influence of organo-clay on the thermal properties of material was significant in composites with O-Mica as fillers, compared to virgin PP. The enhancements of properties can be caused by the formation of intercalated and exfoliation nanocomposite structure at this clay content and stronger interaction of O-Mica with polymer matrix. At a higher filler loading, degradation in mechanical properties maybe attributes to the formation of agglomerated clay tactoids. O-Muscovite/PP Layered Silicate Nanocomposites were prepared via melt compounding using different filler content. Muscovite was organomodified with cetyltrimethylammoniumbromide (CTAB). The thermal and mechanical properties of nanocomposites, based on polypropylene (PP) filled by organo-clay (O-Muscovite), were studied in order to clarify the effect of O-Muscovite on the O-Muscovite/PP layered silicate nanocomposites by WAXD, TEM and DSC analyses. XRD indicated that O-Mica layers were intercalated and dispersed into polypropylene. It was found that the mechanical and thermal properties of organo-clay nanocomposite possess better properties as compared to the unmodified clay nanocomposites. The reason was partly due to the formation of intercalated and exfoliation nanocomposite structure at this clay content and stronger interaction of O-Mica with polymer matrix.

Competitive biosorption of Acid Blue 25 and Acid Red 337 onto unmodified and CDAB-modified biomass of Aspergillus oryzae

The performance of unmodified and cetyldimethylethyl ammonium bromide (CDAB) modified nonviable Aspergillus oryzae for removal of Acid Blue 25 (AB 25) and Acid Red 337 (AR 337) was investigated in single and binary systems. In single system, the biosorption capacities of CDAB-modified biosorbent reached 160.36 and 280.39 mg g −1 for AB 25 and AR 337, respectively, which were 1.52 and 1.66 times higher than that of unmodified biosorbent. In binary system, the biosorption capacities of unmodified and CDAB-modified biosorbents for both dyes decreased significantly compared to that in single system. Relative competitiveness analysis demonstrated that there existed critical initial concentration ratio which determined the predominance of dyes during biosorption process. The biosorption of AB 25 was found to be in dominant position at initial concentration ratio of [AB 25]/[AR 337] above 0.63. Kinetic analysis indicated that intraparticle diffusion was the limiting step for biosorption of two dyes onto biosorbents.

Factors Affecting Quantification of Total DNA by UV Spectroscopy and PicoGreen Fluorescence

The total amount of DNA in a preparation extracted from tissues can be measured in several ways, each method offering advantages and disadvantages. For the sake of accuracy in quantitation, it is of interest to compare these methodologies and determine if good correlation can be achieved between them. Different answers can also be clues to the physical state of the DNA. In this study, we investigated the lack of correlation between ultraviolet (UV) absorbance and fluorescent (PicoGreen) measurements of the concentration of DNAs isolated from plant tissues. We found that quantitation based on the absorbance-based method correlated with quantitation based on phosphorus content, while the PicoGreen-based method did not. We also found evidence of the production of single-stranded DNA under conditions where the DNA was not fragmented into small pieces. The PicoGreen fluorescent signal was dependent on DNA fragment size but only if the DNA was in pure water, while DNA in buffer was much less sensitive. Finally, we document the high sensitivity of the PicoGreen assays to the detergent known as CTAB (cetyldimethylethylammonium bromide). The CTAB-based method is highly popular for low-cost DNA extraction with many published variations for plant and other tissues. The removal of residual CTAB is important for accurate quantitation of DNA using PicoGreen.

The aggregation of branched polyethylenimine and cationic surfactants in aqueous systems

The aggregation of binary mixtures of branched polyethylenimine with a molecular mass of 30 000 and cationic surfactants, such as cetyltrimethylammonium bromide, cetyldimethylethylammonium bromide, or cetyldimethyl(2-hydroxyethyl)ammonium bromide, in aqueous solutions is studied. The critical micellization concentrations, as well as the sizes and shapes of aggregates, are determined by conductometry, small-angle neutron scattering, and dynamic light scattering methods. Catalytic activity of cationic surfactant-polyethylenimine compositions in the hydrolysis of tetracoordinated phosphorus acid 4-nitrophenyl esters is studied via spectrophotometry. The influence of spatial characteristics of aggregates on the catalytic activity and selectivity of nanostructured polymeric systems is revealed.

Headgroup effect on drag reduction and rheological properties of micellar solutions of quaternary ammonium surfactants

Two sets of cationic surfactants each with essentially the same alkyl chains but different headgroup structures were studied to investigate the effects of surfactant headgroup structure on micelle microstructures, drag reduction (DR) and rheological properties at certain counterion and surfactant concentrations. Cetyldimethylethylammonium bromide (CDMEAB) was compared with alkyltrimethyl ammonium bromide (CnTAB) and benzyldimethyl(hydrogenated tallow)ammonium chloride (DMHTB) was compared with alkyltrimethylammonium chloride (CmTAC), respectively. Surfactants with larger headgroups showed lower high temperature limits for DR. CDMEAB systems have better DR abilities than CnTAB below room temperature but the opposite is true at higher temperatures. DMHTB has stronger counterion binding ability than CmTAC, giving better DR properties than CmTAC at low counterion concentration, but has a lower upper temperature limit for DR. These results provide further understanding of the self-assembly nature of threadlike micelles of cationic surfactants and guidance for design of effective surfactant structures to meet particular DR requirements.

Microspectrophotometric determination of thorium(IV) and uranium(VI) with methylthymol blue

Attempts have been made to improve the sensitivity of complexation reactions of Th I V and U V I with methylthymol blue (MTB) in presence of cationic surfactant cetyldimethylethylammonium bromide (CDEAB). The marked bathochromic shift in λ m a x , considerable increase in sensitivity and extreme stability of these ternary complexes in presence of CDEAB were found to be useful in microdetermination of metal ions under study. The composition and values of conditional formation constants have been evaluated in presence of CDEAB and various analytical parameters, viz. conformity to Beer's law, photometric ranges, Sandell's sensitivity and molar absorptivity have been studied.

DPC와 CDEAB의 혼합마이셀화에 미치는 n-부탄올의 효과

The critical micelle concentration (CMC) and the counterion binding constant ( B) in a mixed micellar state of the Dodecylpyridinium chloride (DPC) with the Cetyldimethylethylammonium bromide (CDEAB) at 25 o C in aqueous solutions of n-butanol were determined as a function of α 1 (the overall mole fraction of DPC) by the use of elec- tric conductivity method. Various thermodynamic parameters ( Xi, γi, Ci, ai M , β, and ∆ Hmix) were calculated by means of the equations derived from the nonideal mixed micellar model. The effect of n-butanol on the mixed micellization of the DPC/CDEAB mixtures has been also studied by analyzing the measured and calculated thermodynamic parameters (CMC, B, and ∆ G o m).

Effect of cationic and non-ionic surfactants on the hydrolysis of N-glutaryl- l-phenylalanine catalysed by chymotrypsin iso-enzymes

The hydrolysis of N-glutaryl- l-phenylalanine p-nitroanilide catalysed by various chymotrypsin (CT) iso-enzymes (α-CT, β-CT, δ-CT, and γ-CT) has been studied in the presence of cationic and non-ionic surfactants at concentration higher than the critical micellar concentration. The enzyme activity was tested in the presence of the following surfactants: cetyltrimethylammonium bromide (CTABr), cetyldimethylethylammonium bromide (CDMEABr), cetyltripropylammonium bromide (CTPABr), Triton X100 (TX100) and polyoxyethylene 9 lauryl ether (PO9). The activity of the iso-enzymes depends on the surfactant concentration and it varies with the surfactant head group dimensions (CTPABr>CDMEABr>CTABr). For all the iso-enzymes, superactivity has been detected only in the presence of CTPABr and CDMEABr. The extent of superactivity depends on the enzyme used (δ-CT>β-CT>γ-CT>α-CT). The observed reaction rate has been compared with the prediction of a theoretical model for enzymatic activity in the presence of surfactant aggregates in aqueous media developed in a previous paper. The results can be explained by introducing an equilibrium relation between the enzyme confined in the free bulk water and in the bound water pseudo-phase, and by allowing for different catalytic behaviours of the two forms of enzyme. The theoretical model enables the initial reaction rate to be related to the substrate concentration with an overall Michaelis–Menten equation. Good agreement has been found between experimental and model predicted values of the kinetic parameters.

Cetyldimethylethylammonium-Selective PVC Electrode Basedon its Ion-Associate with Phosphotungstic Acid

A PVC membrane electrode selective for cetyldimethylethylammonium (CDEA) ion was prepared. The active element is a plasticized poly vinyl chloride membrane containing a dissolved ion associate complex of CDEA with phosphotungstic acid (PTA). The electrode showed a near-Nernstian response within the CDEA+ concentration range 2.34 × 10−6 to 1.96 × 10−4 M at 25 ± 1^C, good selectivity, and is usable within the pH range 3.5–9.0. The isothermal temperature coefficient of the electrode amounted to −0.00012 V/°C. The electrode has been used for the direct determination of cetyldimethylethylammonium bromide either by the standard addition method or by potentiometric titration against PTA.

Kinetis of the reaction of alkaline hydrolysis of thiophosphates in micellar and hexagonal phases of the cetyldimethylethylammonium bromide/NaOH/water system.

Abstract Reactivity of O-p-nitrophenyl-O,O-dimethylthiophosphate ( A ), O-p-nitrophenyl-O,O-diethylthiophosphate ( B ) and O-p-nitrophenyl-O,O-dimethylphosphate ( C ) in alkaline hydrolysis in the cetyldimethylethylammonium bromide (CDAB)/NaOH/water system in micellar (MI) and and hexagonal (E) phases was investigated with the help of the spectrophotometrical method. Kinetic parameters of micellar-catalysed reactions (binding constants and rate constants in micellar pseudophase) are defined from kinetic dependence k obs = f(C CDAB ) in accordance with the pseudophase model. The formation of micelles results in maximum acceleration of the alkaline hydrolysis A and C by 6 and 8 times. The reaction becomes slower in an ordered E-phase in comparison with the Mi-phase for A, B and C by 16, 18 and 9 times, accordingly. The process is inhibited 3 and 5 times accordingly in comparison with aqueous alkaline hydrolysis in the E phase for A and B .

Surfactant effects on the physical properties of mesoporous silica and silicates

Mesostructured silicas and silicates have been synthesized using hydrogels with molar composition: M:26.0SiO 2:5.2(C 2H 5) 4NOH:7.5[CH 3(CH 2) 15N(CH 3) 3] 2O:790H 2O, where M=0, Zr(OC 3H 7) 4 or Ti(OC 4H 9) 4. In all preparations, colloidal silica (Ludox) was used as the source of silica. The hydrothermal transformation at 110°C of these gels produced solids with the hexagonal structure typical of MCM-41 type materials. The effects of chain length and surfactant terminal alkyl groups on the properties of mesoporous materials containing Ti or Zr, have been investigated by using different surfactants such as cetyl trimethyl ammonium bromide and chloride, cetyl dimethyl ethyl ammonium bromide, and myristyl trimethyl ammonium bromide. When the surfactant's carbonyl chain decreased to 14 from 16 carbon atoms, a reduction in unit cell dimension and average pore diameter was observed in the mesoporous silicas, titaniumsilicates and zirconiumsilicates under study. Replacement of methyl groups with ethyl groups on the surfactant hydrophobic head, had no measurable effects on crystals' properties. However, a surfactant with a bulky aromatic head group, such as cetyl pyridinium chloride, inhibited crystallization. In general, the use of bromide in place of chloride salts yielded more ordered MCM-41 type crystals. The high thermal stability (to 800°C), surface area (1000–1500 m 2/g), pore volume (0.90–1.20 cm 3/g) and uniform mesoporosity (with pore diameter in the 2.9 nm–3.6 nm range), of these metalsilicates could be of particular interest in the preparation of catalysts requiring siliceous metal supports.

PHYSICAL CHEMICAL STUDIES OF THE AGGREGATION AND CATALYTIC PROPERTIES OF THE SURFACTANT CETYLDIMETHYLETHYLAMMONIUM BROMIDE (CDEAB)

The micellization of cetyldimethylethylammonium bromide (CDEAB) in water was studied by means of surface tensiometry. The critical micellar concentration (CMC) was determined at 25°, 32°, and 40°C, and thermodynamic properties such as the free energy of micellization (∆G°mic), enthalpy (∆H°mic) and entropy (∆S°mic) of micellization were measured. The CMC at 25°C was 9.05 x 10-4 M and the corresponding values of the thermodynamic parameters were: ∆G°mic = -4.15 kcal/mol; ∆H°mic = -1.37 kcal/mol and ∆S°mic = + 9.33 e.u. Micelles of the surfactant CDEAB were good catalysts for the alkaline hydrolysis of p-nitrophenyl diphenyl phosphate (NPDPP) with a maximum catalytic factor of approximately 80, comparable to that of CTAB. Typical activation parameters measured for 0.005 M NaOH were: Ea = 9.0 kcal/mol; ∆H°≠ = 8.4 kcal/mol; ∆G°≠ = 19.2 kcal/mol and ∆S°≠ = -36.3 e.u. The kinetic results were also analyzed in terms of the pseudo-phase ion-exchange models (PPIE) and showed that the model is applicable and gave reasonable fits

Kinetics of alkaline hydrolysis of esters of phosphorus acids in micellar and hexagonal phases in the cetyldimethylethylammonium bromide—NaOH—water system

The influence of micellar (Mi) and hexagonal (E) mesophases of the cetyldimethylethylammonium bromide—NaOH—water system (I) on the rates on alkaline hydrolysis ofO-p-nitrophenyl-O,O-diethyl phosphate (2),O-p-nitrophenyl-O-ethylethyl phosphonate (3), andO,O-di(p-nitrophenyl)methyl phosphonate (4) was studied by UV spectrophotometry. The binding constants of the substrates, critical micelle concentrations, and rate constants of reactions in the micellar phase were determined. In micellar solutions of systemI, a tenfold increase in the rates of alkaline hydrolysis of2–4 was observed. An increase in the degree of medium ordering during the formation of the E-phase results in a twofold acceleration of alkaline hydrolysis of2 and3 and in the inhibition of this process in the case of4.