Cetyltrimethylamonium Bromide Research Articles

Removal of beta-lactam antibiotic in water environment by adsorption technique using cationic surfactant functionalized nanosilica rice husk

This study aims to investigate the adsorption characteristics of cationic surfactant, cetyltrimethylamonium bromide (CTAB) onto negatively nanosilica rice husk surface and the application for antibiotic treatment in water environment. Adsorption of CTAB onto nanosilica increased with an increase of solution pH, due to an enhancement of the electrostatic attraction between cationic methylamomethylamonium groups and negatively charged nanosilica surface enhanced at higher pH. Adsorption of CTAB decreased with a decrease of ionic strength while a common intersection point (CIP) was observed for adsorption isotherm at different ionic strengths, suggesting that hydrophobic interactions between alkyl chains in CTAB molecules significantly induced adsorption and admicelles with bilayer formation were dominant than monolayer of hemimicelles. The CTAB functionalized nanosilica (CFNS) was applied for removal of beta-lactam amoxicillin (AMX). The best conditions for AMX treatment using CFNS were selected as pH 10, contact time 60 min and CFNS dosage 10 mg/mL. Removal efficiency of AMX using CFNS reached to 100% under optimum conditions while it was only 25.01% using nanosilica without CTAB. The maximum AMX adsorption capacity using CFNS of about 25 mg/g was much higher than other adsorbents. The effects of different organics such as humic acid, anionic surfactant, and other antibiotics on AMX removal using CFNS were also studied. A two-step model can fit CTAB uptake isotherms onto nanosilica and AMX onto CFNS well at different KCl concentrations. Based on the desorption of CTAB with AMX adsorption as well as adsorption isotherms, the change in surface charge and functional vibration groups after adsorption, we indicate that AMX adsorption onto CFNS was mainly controlled by electrostatic interaction. We reveal that CFNS is an excellent adsorbent for antibiotic treatment from aqueous solution.

Adsorptive removal of residual amoxicillin antibiotic using cationic surfactant cetyltrimethylamonium bromide modified nanosilica rice husk

Amoxicillin (AMX) is a highly antibiotic resistance so that many studies focus on the removal of AMX in water environment. The present study investigated adsorptive removal of beta-lactam antibiotic AMX using a cationic surfactant, cetyltrimethylamonium bromide (CTAB) modified nanosilica (CMNS). The CTAB adsorption on nanosilica was independent of ionic strength, indicating that both electrostatic and hydrophobic interaction induced adsorption. Effective conditions for AMX removal using CMNS were systematically studied. The AMX removal using 10 mg/ mL CMNS reached 99 % at pH 9. Adsorption isotherms of AMX on CMNS at two salt concentrations were in good agreement with Langmuir model than Freundlich model. Adsorption isotherms at different ionic strengths and the surface modification by Fourier transform infrared (FT-IR) spectroscopy demonstrate that AMX adsorption on CMNS was mainly controlled by electrostatic interaction.

Organic Composomes as Supramolecular Aptamers.

Information contained in the sequences of biological polymers such as DNA and protein is crucial to determining their function. Lipids are not generally thought of as information-containing molecules. However, from a supramolecular perspective, the number of possible combinations of lipids in a mixture is comparable to the complexity of DNA or proteins. Here, we test the idea that an organic composome can exhibit molecular recognition. We use water/octanol as a model two-phase system and investigate the effect of organic solutes in different combinations in the organic phase on selective partitioning of two water-soluble dyes (Brilliant Blue FCF and Allura Red AC) from the aqueous phase into the organic phase. We found that variation in the concentration of the surfactant cetyltrimethylamonium bromide (CTAB) in the octanol phase alone was sufficient to cause a switch in selectivity, with low CTAB concentrations being selective for the red dye and high CTAB concentrations being selective for the blue dye. Other organic components were added to the organic phase to introduce molecular diversity into the composome and directed evolution was used to optimize the relative concentrations of the solutes. An improvement of selective partitioning in the heterogeneous system over the pure CTAB solution was observed. The results indicate that supramolecular composomes are sufficient for molecular recognition processes in a way analogous to nucleic acid aptamers.

Fabrication of gold nanoparticles within hierarchically ZSM-5-based micro-/mesostructures (MMZ) with enhanced stability for catalytic reduction of p-nitrophenol and methylene blue

Gold nanoparticles (Au NPs) have received great attention in diverse catalytic reactions due to their excellent activity. However, the activity is severely relying on dispersion and size of Au NPs. Therefore, regulation of Au NPs for degradation of organic pollutants in water is of vital significance for environmental remediation. Herein, we developed microporous/mesoporous silica, MMZ, using ZSM-5 (SiO2/Al2O3 = 28) as structural constructing precursor and cetyltrimethylamoniumbromide (CTAB) as template via sequential dissolution-self-assembly strategy. The Au precursor is introduced into MMZ and ZSM-5 by ultrasound assisted impregnation and subsequent reduced for Au0 formation. The obtained materials were characterized by XRD, TEM, XPS, SEM, UV-DRS, N2 adsorption and TG/DTG techniques. XRD and TEM study revealed that up to1.0 wt% of Au can be well dispersed with smaller size of 2.8 nm in the material from MMZ (denoted as 1.0Au/MMZ), while serious aggregation and formation of large Au NPs occurs over ZSM-5 with the same Au loading (denoted as 1.0Au/ZSM-5). Catalytic studies also demonstrated that Au/MMZ has much higher catalytic activity for reduction of p-nitrophenol (P-NP) and methylene blue (MB) to p-aminophenol (P-AP) and leuco methylene blue compared with Au/ZSM-5 analogue and other reported Au-based catalysts previously. Moreover, Au/MMZ has good reusability and showed no change in its original catalytic performance till 7th cycles in reduction of P-NP and MB, which is attributed to stable structure and well dispersion of Au NPs over MMZ. Therefore, compared with other Au based catalysts used for catalytic reaction, this Au/MMZ is cheap and promising for industrial applications.

Multivariate Optimization for Preconcentration and Separation of Brilliant Green using Magnetite Nanoparticles Functionalized by Cetyltrimethylamonium Bromide

Adsorptive removal and preconcentration of Brilliant Green (BG) on Fe3O4 magnetic nanoparticles functionalized with cetyltrimethylamonium bromide (CTAB) was investigated in a batch system. The method was based on the analyte adsorption and direct determination by UV–visible spectrophotometry. Various experimental factors such as pH, adsorbent dose (m) and initial concentration (cd) were evaluated and optimized using Box-Behnken design through adsorption of BG on the modified adsorbent. The optimized conditions for maximum removal efficacy (99%) were: pH 9; amount of nanoparticles, 7.1 mg; CTAB, 5.4 mg and cd = 100 mg/L. Under optimum conditions, preconcentration of BG with enrichment factor of 35, LOD = 4 µg/L and RSD = 2.7% (n = 10) for 10 µg/L sample were achieved. The maximum monolayer adsorption of BG onto nano-Fe3O4‒CTAB through running Langmuir isotherm was obtained as 416 mg/g. The morphology and characteristics of the prepared nano-Fe3O4‒CTAB were investigated by scanning electron microscopy, X-ray diffraction, vibrating sample magnetometer, Fourier transform infrared spectroscopy and thermogravimetric analysis.

Rheo-kinetics of bovine serum albumin in catanionic surfactant systems

The effects of catanionic surfactant systems consisting of mixtures of cationic cetyltrimethylamonium bromide (CTAB) and anionic sodium dodecyl sulfate (SDS) on the rheological properties and kinetics of bovine serum albumin (BSA) were investigated. The ionic strength of the solution was varied by using different mixing ratio of SDS and CTAB. Gelation curves observed in dynamic viscoelastic measurements were fitted with gelation kinetics models to describe the gelation under isothermal and non-isothermal conditions. Overall, the gelation of BSA in cationic-rich solutions was found to be more energetically favorable when compared with BSA solvated in anionic-rich solutions. Consequently, highest gel temperature (Tgel) and time (tgel) were observed for anionic-rich solutions with SDS/CTAB molar ratio of 4.0 (i.e., SDS/CTAB=4.0), while lowest gel temperature and time were found for cationic-rich solutions with SDS/CTAB molar ratio of 0.25 (SDS/CTAB=0.25). BSA in equal molar ratio of the mixed surfactants (SDS/CTAB=1.0) showed a gel temperature and time in the halfway between the anionic and cationic-rich regions. Interestingly, under isothermal and non-isothermal conditions, BSA in equimolarly mixed and anionic-rich solutions showed a heat-dependent protective effect against thermal denaturation and gelation. The protective effect on BSA gelation in equimolar and anionic-rich solutions was diminished by increasing the catanionic concentration under non-isothermal conditions, while under isothermal conditions, protective effect on BSA gelation increased with catanionic concentration. On the other hand, cationic-rich solutions did not protect BSA from thermal denaturation and gelation, and therefore the gelation rate increased with catanionic concentration in all heating conditions examined.

Strong UV Emission from Colloidal Eu2+‐Doped BaSO4 Nanoparticles: A Material for Enhancing the Photocatalytic Activity of Carbon Dots

AbstractIn this article, we report a facile microwave‐assisted green synthetic route for the preparation of highly luminescent water dispersible polyacrylic acid‐coated europium (Eu2+)‐doped BaSO4 nanoparticles at low temperature for the first time. Polyacrylic acid coating over nanoparticles renders them water dispersible. Upon ultraviolet (UV) (250 nm) excitation, europium‐doped BaSO4 nanoparticles exhibit a strong and broad UV luminescence near at 368 nm. This emission peak is quite strong and has a relative luminescence quantum yield (QY) of 53 %. The high QY of the UV emission from the nanoparticles is explored for the enhancement of the visible photocatalytic properties of the carbon dots (Cdots). In fact, faster degradation of the Rhodamine B is noted for the mixture containing both Eu2+‐doped BaSO4 nanoparticles and cetyl trimethylamonium bromide capped carbon dots. This is attributed to the strong overlap of the UV emission of Eu2+ with the absorption spectrum of Cdots leading to high energy transfer efficiency (∼64 %). The energy transfer process is supported by the observation of lower dye degradation for the diluted colloidal mixtures where the average distance between Eu2+ in BaSO4 to Cdots nanoparticles is increased.

Binding of Sulfonamide Antibiotics to CTABr Micelles Characterized Using (1)H NMR Spectroscopy.

Interactions of nine sulfonamide antibiotics (sulfadoxine, sulfathiazole, sulfamethoxazole, sulfamerazine, sulfadiazine, sulfamethazine, sulfacetamide, sulfaguanidine, and sulfanilamide) with cetyltrimethylamonium bromide (CTABr) micelles were examined using (1)H NMR spectroscopy. Seven of the nine provided a significant change in the (1)H NMR chemical shift such that the magnitude and direction (upfield vs downfield) of the chemical shift could be used to propose a locus and orientation of the sulfonamide within the micelle structure. The magnitude of the chemical shift was used to estimate the binding constant for seven sulfonamides with CTABr micelles, providing values and an overall pattern consistent with previous studies of these sulfonamides.

Synthesis and spectroscopic characterization of gold nanobipyramids prepared by a chemical reduction method

Gold nanobipyramids (NBPs) have attracted much attention because they have potential for applications in smart sensing devices, such as medical diagnostic equippments. This is due to the fact that they show more advantageous plasmonic properties than other gold nanostructures. We describe a chemical reduction method for synthesizing NBPs using conventional heating with ascorbic acid reduction and cetyltrimethylamonium bromide (CTAB) + AgNO3 as capping agents. The product was characterized by ultraviolet–visible spectroscopy (UV–vis), Fourier transmission infrared spectroscopy (FTIR), transmission electron microscopy (TEM), x-ray powder diffraction (XRD). The results showed that gold nanoparticles were formed with bipyramid shape (tip-to-tip distance of 88.4 ± 9.4 nm and base length of 29.9 ± 3.2 nm) and face-centered-cubic crystalline structure. Optimum parameters for preparation of NBPs are also found.

Aging process of some pyrogenic silica samples exposed to controlled relative humidities

Abstract In the present study, we have examined the influence of the aging process under controlled relative humidity on the surface properties of 3 silicas samples of increasing specific surface area. Both comparison of the specific surface areas, determined using either nitrogen (BET) or cetyltrimethylamonium bromide (CTAB), and the surface nanoroughness indexes, determined by size exclusion inverse gas chromatography, indicates that the ageing process has no significant influence on the surface morphology at the molecular level. On the contrary, IGC at finite concentration using isopropanol as probe evidences clearly an increase of the surface heterogeneity induced by the formation of new silanol groups into the preexisting hydrophilic domains by opening of siloxane bridges by water.

P.3.d.047 Non-adherence factors in the treatment of psychotic disorders

Nanostructured materials have exceptional and highly attractive properties, including catalyst, adsorbent, separation media and chemo sensor. Technical advances in these fields require the development of ordered porous materials with controllable structures, systematic tailoring pore architecture and the synthesis of mesoporous materials using a more economical silica source. Ordered mesoporous silica SBA-3 material has been synthesized successfully using cetyltrimethylamonium bromide (CTAB) as a structure-directing agent, NaOH and inexpensive silica gel as a silica source without additives. We studied the influence of NaOH concentration on the structure and morphology of mesoporous silica SBA-3. This variation was defined as modulus L=[NaOH/SiO2] ratio. The structural order of the samples was found to be greatly affected by L variations. The results suggest that, by controlling the L value (0.70–1), SBA-3 is obtained with appropriate physicochemical characteristics.

Synthesis of ordered mesoporous SBA-3 materials using silica gel as silica source

Nanostructured materials have exceptional and highly attractive properties, including catalyst, adsorbent, separation media and chemo sensor. Technical advances in these fields require the development of ordered porous materials with controllable structures, systematic tailoring pore architecture and the synthesis of mesoporous materials using a more economical silica source. Ordered mesoporous silica SBA-3 material has been synthesized successfully using cetyltrimethylamonium bromide (CTAB) as a structure-directing agent, NaOH and inexpensive silica gel as a silica source without additives. We studied the influence of NaOH concentration on the structure and morphology of mesoporous silica SBA-3. This variation was defined as modulus L=[NaOH/SiO2] ratio. The structural order of the samples was found to be greatly affected by L variations. The results suggest that, by controlling the L value (0.70–1), SBA-3 is obtained with appropriate physicochemical characteristics.

The influence of temperature on the adsorption of CTAB on coals

The influence of temperature on the adsorption behavior of the cationic surfactant cetyltrimethyl amonium bromide (CTAB) has been studied. Batch mode was used for the adsorption of CTAB on three different types of coal, namely oxidative altered coal (BO), subbituminous coal (SB) and bituminous coal (BC). Adsorption from aqueous solutions was carried out at 25, 40, 60 and 80 °C. The linear as well as nonlinear regression of experimental data confirmed that the adsorption process can be described using the Langmuir adsorption theory of monolayer coverage. Thus, the equilibrium constant of adsorption could be calculated from the Langmuir binding constant b. Further, thermodynamic parameters such as enthalpy Δ H ads, entropy Δ S ads and Gibbs energy Δ G ads were determined from the dependence of the b constant on temperature. The calculated thermodynamic parameters indicate that the adsorption of CTAB on coals is an exothermic (Δ H ads < 0) and spontaneous (Δ G ads < 0) process. It was proved that the adsorption capacity of CTAB on coal increased with a rise in temperature for all the studied samples; the highest adsorption capacity was observed for the oxidative altered coal. Moreover, a close relationship between the adsorption capacity and the critical micelle concentration (CMC) of CTAB has been discovered. In addition, measuring the zeta potential proved that the adsorbed amount of CTAB on the coal surface corresponded to the zeta potential value. Addition of the cationic surfactant (CTAB) affects the value of ξ-potential, making the zeta potential values more positive.

A reliable and efficient method for total rna isolation from various members of spurge family (Euphorbiaceae)

It is prerequisite and crucial to extract RNA with high quality and integrity in order to carry out molecular biology studies in any plant species of a family. Euphorbiaceae members are known for high levels of their waxes, oils with polysaccharides, polyphenolics and secondary metabolites. These conditions are recognised to interfere unfavourably with various methodologies of RNA isolation. To develop a simple, rapid and reproducible cetyltrimethylamonium bromide (CTAB)-based protocol, to reduce the time and cost of extraction without reducing quality and yield of RNA extracted from various recalcitrant Euphorbiaceae member plant tissues such as from tree leaves (Hevea brasilensis), woody shrubs leaves (Ricinus communis, Jatropha curcas, Manihot esculenta) and storage root tissue (M. esculenta). Simple modifications and fast steps were introduced to the original CTAB protocol. All centrifugation steps were carried out at 4°C at 12000 rpm for 10 min, the sample weight was decreased and usage of spermidine and LiCl was omitted, reducing incubation time prior to RNA precipitation. This rapid CTAB protocol was compared with various RNA isolation methods intended for use with plants rich in polysaccharides and secondary metabolites. The procedure can be completed within 2 h and many samples can be processed at the same time. RNA of high quality could be isolated from all the tissues of species that we tried. The isolated RNA from different species served as a robust template for RT-PCR analysis. The study has shown that the improvement of a CTAB-based protocol allows the rapid isolation of high-quality RNA from various recalcitrant Euphorbiaceae members.

Synthesis of nickel hierarchical microstructures by a simple hydrothermal route

Nickel hierarchical microstructures have been synthesized from the reduction of nickel hydrazine complexes by a simple hydrothermal method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and superconducting quantum interference device (SQUID). The results indicated that the Ni hierarchical microstructures are face-centered cubic phase with a size of 2–3 μ for a single hierarchical microstructure while some thick petals with a length in the range of 0.5–1.5 μ extrude around the surface. The value of coercivity reached 121 Oe at room temperature, which is vastly superior to that of bulk nickel. Parallel experiments showed that the hydrothermal reaction time and the presence of surfactant cetyltrimethylamonium bromide (CTAB) played important roles in the formation of such hierarchical morphology.

Solubilization Capabilities of Some Cationic, Anionic, and Nonionic Surfactants toward the Poorly Water-Soluble Antibiotic Drug Erythromycin

Surfactants can be used to increase the solubility of poorly soluble drugs in water and to increase drug bioavailability. In this article, solubilization of macrolide antibiotic erythromycin is investigated by employing spectrophotometry and tensiometry in micellar solutions of nonionic (Brij56, Brij58, Brij35, Brij30), cationic (cetyltrimethylamonium bromide, CTAB; tetradecyltrimethylammonium bromide, TTAB; dodecyltrimethylammonium bromide, DTAB), and anionic (sodium dodecylbenzenesulfonate, SDBS; sodium dodecylsulfate, SDS) surfactants and then compared. The results showed that irrespective of the surfactant type, the solubility of erythromycin increases linearly with increasing surfactant concentration, as a consequence of association between the drug and micelles. Solubilization capacity has been quantified in terms of molar solubilization ratio (Rm,S), micelle−water partition coefficient (KM), binding constant (K1) between solubilizate monomer and vacant micelle, and the free energy of solubilization (ΔGso) of the drug in the micelles. Cationic surfactants of the same chain length as that of nonionic and anionic surfactants exhibited higher solubilization capacity, probably due to solubilization at the micelle−water interfaces. The order of solubilization powers among nonionic, cationic, and anionic surfactants for erythromycin was found to be Brij56 > Brij58 > Brij35 > Brij30, CTAB > TTAB > DTAB, and SDBS > SDS, respectively. This comparative study can be used to select an appropriate medium for erythromycin solubilization, where nonionic surfactants are advantageous due to their minimal protein binding and retention of their micellar form even after large dilution in blood owing to their very low critical micellar concentration (cmc) values.

Templated Synthesis of Gold Nanorods (NRs): The Effects of Cosurfactants and Electrolytes on the Shape and Optical Properties

Seeded growth of gold nanorods (NRs) has been accomplished in a micellar medium containing mixed surfactants or a high salt concentration. Cetyl trimethylamoniumbromide (CTAB) forms micelles upon which the growth of rod shaped gold nanoparticles occurs. AgNO3 is introduced into the growth solution to enhance the formation of NRs. The roles of non-ionic surfactants such as Tween and Triton, and of electrolytes such as sodium chloride and potassium chloride have been examined. As the concentration of these additives in the growth solution is increased, the aspect ratio of the NRs increases to a critical limit, after which it decreases again. Upon carefully controlling the content of Triton X-100 or Tween 20 in the growth solution, these non-ionic surfactants assisted in fine-tuning the shape of gold NRs (e.g. rectangular or “dogbone”). The growth pattern of the NRs fits into the model of a soft template formed by the mixture of CTAB and non-ionic surfactants.

Micellar versus hydro-organic reversed-phase liquid chromatography: A solvation parameter-based perspective

The performance of the solvation parameter model is examined for micellar liquid chromatography. The results are compared with those offered with hydro-organic eluents, intending to reveal the properties that influence the retention and distinguish the particular behaviour of micellar systems. The retention data of several series of non-ionisable and ionisable compounds (mainly steroids, polyaromatic hydrocarbons, phenols, sulfonamides, β-blockers, phenethylamines, antihistamines, and diuretics) were used as probe compounds. The micellar mobile phases contained an anionic (sodium dodecyl sulphate), non-ionic (Brij-35), or cationic (cetyltrimethylamonium bromide) surfactant, with or without the addition of an organic solvent (either propanol, butanol, pentanol or acetonitrile). In some instances (steroids, sulfonamides, β-blockers and diuretics), the processed data were obtained in both micellar and hydro-organic chromatographic modes using the same column. Accuracy in predictions is critically examined and a correction term that takes into account contributions not considered in the original Abraham model, such as electrostatic or steric ones, is suggested to improve the correlations. The proposed correction takes into account differences between the descriptors of ionic and neutral species. The case of compounds showing different degrees of ionisation is discussed. Three solvation parameter approaches that allow the prediction of retention at varying mobile phase composition are proposed, which also revealed differences between the micellar and hydro-organic modes.

Ordered circular mesoporosity induced by phospholipids

Circular mesoporous materials with different geometries have been prepared by surfactant-templated sol–gel synthesis involving the condensation of tetraethylortosilicate (TEOS) under basic conditions. In this study, cetyltrimethylamonium bromide (CTAB) has been used as a surfactant and controlled amounts of l-α-phosphatidylcholine (lecithin) as a co-surfactant. For small concentrations of lecithin, the obtained materials retain the hexagonal pore ordering characteristic of MCM-41, as evidenced by X-ray diffraction and electron microscopy. However, the channels are no longer straight and parallel but circular and concentric. At higher concentrations of lecithin, vesicular silica was produced.

HPMC effect on catalyzed hydrolysis of α-naphthyl acetate in cationic micellar systems

Micelle formation is an important property of surfactants. Micellar solutions of cetyltrimethylamonium bromide (CTAB) have been found to accelerate the hydrolysis of α-naphthyl acetate (α-NA) by o-iodosobenzoic acid (IBA), a strong nucleophile. Critical micelle concentration (CMC) of CTAB was determined in the absence and presence of various concentrations and grades of hydroxypropylmethyl cellulose (HPMC) using surface tension measurement. Reaction under pseudo-first-order condition was utilized for rate constant determination. The aggregation of CTAB in the polymer solution started at higher concentration than in the absence of the polymer. The observed rate constants for the degradation of α-NA in the presence of various concentrations of CTAB with and without HPMC were calculated. The presence of HPMC retarded the reaction rate. However, there was no obvious difference in the observed rate constant among the different grades of HPMC (Methocel E50 ®, Methocel E4M ®, Methocel E10M ®) while the higher the polymer concentration the lower the rate constant.