Cetyltrimethylammonium Bromide Research Articles

Structural and optical properties of mesoporous akermanite derived from industrial waste for multifunctional applications

The present study focuses on the synthesis of akermanite by chemical free hydrothermal route using two major industrial waste ground granulated blast furnace slag (GGBS) and coal fly ash (FA) as the initial precursors. Further, leaf extract and Cetyltrimethyl ammonium bromide (CTAB) have been used as stabilizing and chelating agent to observe their effect on the structural, optical and morphological properties of the nanoparticles. The synthesized powders were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), ultraviolet visible (UV–visible) spectroscopy, Brunauer-Emmett-Teller (BET) analyser techniques. The detailed structural studies implied that the fabricated powders are akermanite and the average crystallite size was calculated to be in the range 23–27 nm. Field emission scanning electron microscopy analysis showed that the samples synthesized using water and leaf extract adopt rod like morphology while the sample fabricated using CTAB are seed shaped. The calculated bandgap of the developed powders from the UV-Visible reflectance spectra using Kubelka-Munk method lie in the range 3.1–3.26 eV. BET analysis revealed all the samples are mesoporous in nature and their specific surface area were estimated.

Preparation of modified Jordanian bentonite with cetyltrimethylammonium bromide as novel adsorbent for phosphate ion removal from synthetic and real wastewater

Jordanian bentonite was examined for its capacity to remove phosphate ions from aqueous solutions, both synthetic and natural. by converting Jordanian bentonite to organo-bentonite (CTAB-bentonite). Investigation on the ability of organo-bentonite to remove phosphate ions under different conditions including initial concentration, temperature, particle size, pH levels, adsorbent dosage, and contact time. Kinetic experiments results were analyzed employing first and second pseudo order models. The results of R2 for both kinetic models confirmed that fill in the pseudo- second-order and was preferred for the transport of phosphates other than pseudo-first order. For both synthetic and actual wastewater, the activation energy for removal was computed and determined to be 22.88 kJ/mol and 58.73 kJ/mol, respectively. The rate of phosphate ion absorbing was investigated at different temperatures, particle sizes, agitation levels, and pH values. The study predicted both particle diffusion (Dp) and film diffusion (Df) coefficients, concluding that film diffusion (Df) determines rate.

Enhancing the Antimicrobial Properties of Experimental Resin-Based Dental Composites through the Addition of Quaternary Ammonium Salts.

Secondary caries is one of the main reasons for dental filling replacement. There is a need to obtain dental restorative material that is able to act against caries-inducing microorganisms. This study explores the antimicrobial properties of cetyltrimethylammonium bromide (CTAB) or dimethyldioctadecylammonium bromide (DODAB)-modified photo-cured experimental dental composites against Escherichia coli, Streptococcus mutans, and Candida albicans. The antimicrobial activity against Escherichia coli, Streptococcus mutans, and Candida albicans was assessed by using an Accuri C6 flow cytofluorimeter, and then analyzed using BD CSampler software (1.0.264). Bacterial/yeast surface colonization was carried out by using an GX71 inverted-optics fluorescence microscope equipped with a DP 73 digital camera. For bactericidal surface analysis of each sample type, simultaneous standardization was performed using a positive control (live cells) and a negative control (dead cells). A positive correlation between the increasing concentration of CTAB or DODAB and the dead cell ratio of Escherichia coli, Streptococcus mutans, and Candida albicans was revealed. In particular, CTAB at a 2.0 wt% concentration exhibits superior efficiency against pathogens (65.0% dead cells of Escherichia coli, 73.9% dead cells of Streptococcus mutans, and 23.9% dead cells of Candida albicans after 60 min). However, Candida albicans is more resistant to used salts than bacteria. A CTAB- or DODAB-modified experimental dental composite exhibits antimicrobial potential against Escherichia coli, Streptococcus mutans, and Candida albicans after 10 and 60 min of incubation, and the antimicrobial efficiency increases with the wt% of QAS in the tested material.

Microwave-assisted synthesis and functionalization of nanocrystalline molybdenum trioxide for enhanced antimicrobial and photocatalytic activity

Molybdenum Trioxide nanoparticles (MoO3) were synthesized using ammonium heptamolybdate tetrahydrate [(NH4)6Mo7O24·4H2O] as the primary precursor via the microwave-assisted method and subsequently functionalized with surfactants such as Cetyltrimethylammonium bromide (CTAB), Sodium n-dodecyl sulfate (SDS), and Thioglycolic acid (TGA). The characterization involved X-ray diffraction, field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and UV–Visible spectroscopy, revealing hexagonal plate-like morphology, UV absorbance at 202–216 nm with a band gap of 4.2 eV, and a crystalline structure with a 44 nm size calculated by the Scherrer's equation. The synthesized pure (MoO3) and functionalized molybdenum trioxide nanoparticles (FMoO3) were tested for antibacterial activity against gram-positive Staphylococcus aureus and gram-negative Salmonella typhi. Furthermore, MoO3 and FMoO3 also demonstrated enhanced antifungal activity against the fungi Aspergillus niger (Accession No. MZ435922) and Aspergillus fumigatus (Accession No. MZ435863). Photocatalytic experiments demonstrated significant degradation of malachite green dye under UV light irradiation, notably with SDS functionalized MoO3 achieving 98.17 % degradation rate within 20 min, with a linear rate constant of 0.20343 min−1. These findings highlight the potential of MoO3 and FMoO3 nanoparticles as effective antimicrobial agents and their suitability for water purification due to their low toxicity.

Surfactant-assisted hydrothermal synthesis of FeVO4 nanoparticles for supercapacitor applications

Due to their high capacitance, stability, and conductivity, binary transition metal oxides, such as iron vanadate, have the potential to be ideal electrode materials for supercapacitors. The effect of surfactants such as polyethylene glycol, cetyltrimethylammonium bromide, and thioglycolic acid (TGA) on the formation and properties (structural, morphological, optical, and vibrational) of iron vanadate nanoparticles has been investigated using various analytical techniques. The results show that the surfactants significantly influence the morphology of the prepared FeVO4 nanoparticles. The nanoparticles prepared using TGA show a nanomat-like structure with the smallest particle size, and they were subjected to Cyclic Voltammetry analysis, showing a specific capacitance of 48 Fg−1 and demonstrating potential to be used for supercapacitors.

Lipid-Based Catalysis Demonstrated by Bilayer-Enabled Ester Hydrolysis.

Lipids have not traditionally been considered likely candidates for catalyzing reactions in biological systems. However, there is significant evidence that aggregates of amphiphilic compounds are capable of catalyzing reactions in synthetic organic chemistry. Here, we demonstrate the potential for the hydrophobic region of a lipid bilayer to provide an environment suitable for catalysis by means of a lipid aggregate capable of speeding up a chemical reaction. By bringing organic molecules into the nonpolar or hydrophobic region of a lipid bilayer, reactions can be catalyzed by individual or collections of small, nonpolar, or amphiphilic molecules. We demonstrate this concept by the ester hydrolysis of calcein-AM to produce a fluorescent product, which is a widely used assay for esterase activity in cells. The reaction was first carried out in a two-phase octanol-water system, with the organic phase containing the cationic amphiphiles cetyltrimethylammonium bromide (CTAB) or octadecylamine. The octanol phase was then replaced with phospholipid vesicles in water, where the reaction was also found to be carried out. The reaction was monitored using quantitative fluorescence, which revealed catalytic turnover numbers on a scale of 10-7 to 10-8 s-1 for each system, which is much slower than enzymatic catalysis. The reaction product was characterized by 1H-NMR measurements, which were consistent with ester hydrolysis. The implications of thinking about lipids and lipid aggregates as catalytic entities are discussed in the context of biochemistry, pharmacology, and synthetic biology.

Improvement of the Oxidative Desulfurization Performance Using MoO3/CuO‐Modified Hierarchical HY Zeolite

AbstractThe presence of sulfur compounds in the chemical industry poses significant environmental and economic problems, including endangering human and animal lives and damaging equipment. For this purpose, hierarchical HY zeolite (Hie‐Y) with a SiO2/Al2O3 molar ratio 10 was successfully synthesized through sequential desilication‐dealumination using NH4OH treatment. A weak alkaline media with surfactant cetyltrimethylammonium bromide (CTAB) facilitates mesoporosity formation and preserves the zeolite structure. Metal oxide (CuO, MoO3) ‐ hierarchical HY zeolite nanocomposites have been prepared by one or a combination of 3 methods: 1) ion exchange, 2) precipitation, and 3) calcination. The obtained catalysts were characterized using XRD, FT‐IR, FESEM, UV‐Vis, EDS, and BET techniques. The formation of a hierarchical structure is associated with structure preservation, but partial destruction occurs based on the entering Cu in the zeolite pores. These catalysts have been studied in the oxidative desulfurization (ODS) reaction. Several parameters, including temperature, catalyst amount, DBT concentration, and reaction time, were evaluated in ODS using the Taguchi Design of Experiments. Catalytic activity order was obtained as Y<Hie‐Y<Hie‐Y/CuO<Hie‐Y/MoO3<Hie‐Y/MoO3/CuO. Results indicate an activity increase for the Hie‐Y/MoO3/CuO hierarchical structure owing to synergistic effects of secondary mesoporosity and metal oxides. The catalyst was recoverable and reused for five consecutive runs with preservation of catalytic activity.

Investigation of physical properties of microalgae‐pectin‐based bio‐composite with addition of pine needle for environmental application

AbstractPolymers and biopolymers have gained significance due to their applicability and use in industry reducing the negative impact of polymers based on petroleum. A possible solution for the conventional polymer's biodegradability is bio‐composites, which contain natural fibers or aggregates such as microalgae. Hence, microalgae biomass has a promising application to address the biodegradability issue of conventional polymers. In this study, Chlorella vulgaris biomass was mixed with pectin for control samples with glycerol as plasticizer. The mixture microalgae‐pectin‐glycerol, and the addition of pine needles was used to evaluate the tensile strength and compression of the bio‐composite. This bio‐composite showed a higher Young's modulus of 95.66 MPa for blend C2 and a higher strength with 20% of pectin concentration in the mixture. Additionally, the pine needle addition did not have a low effect between the compression results. On the other hand, analysis on elasticity showed that the full recovery of the bio‐composite happened after 10 min in all the blends. Also, the bio‐composite showed a slow release of nitrogen and phosphorous after 5 days of water addition, indicating an effective slow release for blend B for both nutrients. Water uptake capacity and loss of soluble material was studied using pullulan, chitosan, and cetyltrimethylammonium bromide additives. These cationic surfactants demonstrated their potential for reduction of water solubility of the bio‐composite.

Hydroxyapatite-Filled Acrylonitrile-Butadiene Rubber Composites with Improved Cure Characteristics and Reduced Flammability.

The goal of this work was to develop acrylonitrile-butadiene (NBR) elastomer composites filled with hydroxyapatite (HAP) characterized by improved cure characteristics and resistance to burning. Silane, i.e., (3-aminopropyl)-triethoxysilane, ionic liquid, i.e., 1-decyl-3-methylimidazolium bromide and surfactant, i.e., cetyltrimethylammonium bromide, were used to improve the filler's dispersibility in the elastomer matrix and to reduce the time and temperature of vulcanization. The effects of HAP and dispersants on the cure characteristics, crosslink density and physico-chemical properties of NBR composites were explored. The additives used, especially the ionic liquid and surfactant, effectively improved the dispersion of HAP in the NBR matrix. The amount of HAP and the dispersant used strongly affected the cure characteristics and crosslink density of NBR. The optimal vulcanization time significantly increased with HAP content and was pronouncedly reduced when ionic liquid and surfactant were applied. In addition, ionic liquid and surfactant significantly lowered the onset vulcanization temperature and improved the crosslink density and hardness of the vulcanizates while impairing their elasticity. HAP and dispersants did not significantly affect the damping properties or chemical resistance of NBR vulcanizates. Above all, application of HAP considerably enhanced the resistance of vulcanizates to thermo-oxidative aging and reduced their flammability compared with the unfilled NBR.

Effect of surfactants on the luminescence, bonding, and catalytic properties of CaWO4 spheres

BackgroundThis work focuses on improving the luminescence and catalytic properties of CaWO4 spheres by manipulating their electron density distribution. The goal is to enhance their suitability for optoelectronic applications and to increase their efficiency in degrading the industrial dye methylene blue (MB). The study utilizes a co-precipitation technique and the addition of three surfactants to synthesize phase-pure CaWO4 with a tetragonal crystal structure. MethodsThe synthesis involved a co-precipitation technique with simultaneous addition of three surfactants. Extensive characterization employed various analytical and spectroscopic methods to assess structural, morphological, luminescent, and catalytic properties. Particularly, the use of cetyltrimethylammonium bromide (CTAB) surfactant induced intense green emission around 500 nm attributed to luminescent center WO42−. Solar irradiation evaluated catalytic performance, with CaWO4: CTAB degrading methylene blue remarkably in just 40 min under natural sunlight. Significant FindingsThe research yielded a CaWO4 material, particularly when assisted by the CTAB surfactant, exhibiting intense green luminescence, making it promising for optoelectronic applications. Furthermore, this material demonstrated remarkable catalytic performance in degrading methylene blue under solar irradiation, suggesting its potential in environmental remediation. The study also delved into electron density distribution by examining differences in bond lengths and mid-bond electron density within a single unit cell, shedding light on the material's underlying properties.

Room temperature detection of isopropyl alcohol using CTAB-assisted silver-doped ZnO nanorods as chemiresistive gas sensor

In this study, pristine silver-doped zinc oxide (Ag–ZnO) and Plumbago zeylanica leaf extract (PZE) incorporated with Ag–ZnO, along with the additional material of cetyltrimethylammonium bromide (CTAB)-assisted Ag–ZnO nanorods, were synthesized and extensively characterized. The basic properties of the samples were studied and optimized. Gas sensing measurements were conducted, and the obtained results were thoroughly interpreted. The study includes demonstrating and examining pure Ag–ZnO, PZE-added Ag–ZnO, and CTAB-assisted Ag–ZnO. Notably, the presence of CTAB exhibited a favorable effect on the Ag–ZnO, indicating an enhanced isopropyl alcohol gas sensing response time of 20 s at 15 ppm within an ambient temperature. Additionally, improvements in selectivity and reduced sensor resistance in current (nanoampere - nA) were observed in CTAB-assisted Ag–ZnO. The sensing mechanism was investigated, focusing on the depletion layer of Ag–ZnO with the surfactant. The work emphasizes the sensing abilities of PZE-assisted Ag–ZnO and CTAB Ag–ZnO, highlighting the significance of these noble metals in systematic gas sensing applications.

Visible Light-Driven Photocatalytic CH4 Production from an Acetic Acid Solution with Cetyltrimethylammonium Bromide-Assisted ZnIn2S4

Photocatalytic methods have been popular in energy production and environmental remediation. Designing high-efficiency photocatalysts is still challenging in converting solar energy into chemical fuels. Herein, a series of surfactant-assisted ZnIn2S4 (ZIS) photocatalysts were synthesized by utilizing the one-pot hydrothermal method. Photocatalytic methane production from an acetic acid solution was carried out under LED light (450 nm) irradiation, and the evolved gas was analyzed by the GC-FID system. Reaction factors (surfactant amount, catalyst dose, reaction temperature, substrate concentration, and reaction pH) were optimized for photocatalytic production. With the increase in cetyltrimethylammonium bromide (CTAB) amount, CH4 production gradually increased. The ZIS-3.75 photocatalyst exhibited the highest photocatalytic CH4 production rate (0.102 µmol g−1·h−1), which was approximately 1.8 times better than that of pure ZIS (0.058 µmol g−1·h−1). The presence of CTAB reduced the charge transfer resistance and improved photocurrent response efficiency. Structure and morphology were characterized by XRD, FTIR, SEM, TEM, and N2 adsorption–desorption isotherm analysis. Optical properties were investigated by UV-DRS and PL spectroscopic techniques. The electrochemical evaluation was measured through EIS, Mott–Schottky, and transient photocurrent response analysis. The CTAB-modified catalyst showed excellent stability and reusability, even after five irradiation cycles. Methane production was enhanced by lowering the photogenerated charge transfer resistance and boosting the dispersion of ZIS-3.75 under visible light (450 nm) irradiation.

Preparation and application of wormlike micelles generated from a rosin-based aggregation-induced emission surfactant through coordinating aggregation

Fluorescent nanomaterials have drawn considerable attentions due to their high fluorescence sensitivity, excellent signal stability and tunable luminescent properties. A bio-based aggregation-induced emission (AIE) surfactant (Sodium 4-(tetraphenylstyrene)maleate, MPA-TPE-Na) was prepared from rosin, which showed typical AIE characteristic, obvious solvatochromism and a large Stokes shift (>100 nm). AIE viscoelastic solutions were further prepared by complexing MPA-TPE-Na and cetyltrimethylammonium bromide (CTAB) through coordinating aggregation and their microstructure, fluorescence properties and viscoelasticities were investigated. The aggregates in the viscoelastic solutions were wormlike micelles. As the concentration of MPA-TPE-Na increased, the fluorescence intensity of the viscoelastic solutions increased, and their viscosity increased at first and then decreased. The fluorescence emission intensity of the viscoelastic solutions was barely affected by the change in pH. But reducing the pH could increase its viscosity. This system can specifically recognize Fe3+ without any organic solvent and has anti-interference ability. The present work provided a bio-based fluorescent nanomaterial and verified the feasibility of preparing aqueous AIE nanomaterials by modifying AIE groups with rosin skeleton.

Application of a novel mixed anionic/cationic collector in the selective flotation separation of lepidolite and quartz

A novel mixed anionic/cationic collector of sodium dodecyl sulfonate (SDS) and cetyltrimethylammonium bromide (CTAB) was applied in the flotation separation of lepidolite from quartz. The micro-flotation experiment proved that the obvious floatability difference between lepidolite and quartz can achieve their flotation separation in this mixed collector system. The optimum dosage of SDS and CTAB were 60 mg/L and 10 mg/L respectively, and the optimal pulp pH was 7.0. Zeta potential analyses showed that the further adsorption of CTAB affects a positive shift of 17.14 mV in the potential of lepidolite after the pre-adsorption of SDS, while quartz shifted positively by only 4.89 mV. Fourier transform infrared analyses indicated that CTAB and SDS can co-adsorb on the surface of lepidolite to enhance its hydrophobicity. X-ray photoelectron spectroscopy analyses further demonstrated that the mixed collector of SDS and CTAB had a stronger selectivity for adsorption on the lepidolite surface than that of quartz. The adsorption strength of SDS on lepidolite was greater than that of quartz, and the co-adsorption of SDS and CTAB on the surface of lepidolite can additionally enlarge their differences in flotation behavior. These may be the essence of achieving the selective separation of the two minerals.

NANO.PTML model for read-across prediction of nanosystems in neurosciences. computational model and experimental case of study

Neurodegenerative diseases involve progressive neuronal death. Traditional treatments often struggle due to solubility, bioavailability, and crossing the Blood-Brain Barrier (BBB). Nanoparticles (NPs) in biomedical field are garnering growing attention as neurodegenerative disease drugs (NDDs) carrier to the central nervous system. Here, we introduced computational and experimental analysis. In the computational study, a specific IFPTML technique was used, which combined Information Fusion (IF) + Perturbation Theory (PT) + Machine Learning (ML) to select the most promising Nanoparticle Neuronal Disease Drug Delivery (N2D3) systems. For the application of IFPTML model in the nanoscience, NANO.PTML is used. IF-process was carried out between 4403 NDDs assays and 260 cytotoxicity NP assays conducting a dataset of 500,000 cases. The optimal IFPTML was the Decision Tree (DT) algorithm which shown satisfactory performance with specificity values of 96.4% and 96.2%, and sensitivity values of 79.3% and 75.7% in the training (375k/75%) and validation (125k/25%) set. Moreover, the DT model obtained Area Under Receiver Operating Characteristic (AUROC) scores of 0.97 and 0.96 in the training and validation series, highlighting its effectiveness in classification tasks. In the experimental part, two samples of NPs (Fe3O4_A and Fe3O4_B) were synthesized by thermal decomposition of an iron(III) oleate (FeOl) precursor and structurally characterized by different methods. Additionally, in order to make the as-synthesized hydrophobic NPs (Fe3O4_A and Fe3O4_B) soluble in water the amphiphilic CTAB (Cetyl Trimethyl Ammonium Bromide) molecule was employed. Therefore, to conduct a study with a wider range of NP system variants, an experimental illustrative simulation experiment was performed using the IFPTML-DT model. For this, a set of 500,000 prediction dataset was created. The outcome of this experiment highlighted certain NANO.PTML systems as promising candidates for further investigation. The NANO.PTML approach holds potential to accelerate experimental investigations and offer initial insights into various NP and NDDs compounds, serving as an efficient alternative to time-consuming trial-and-error procedures.

Hydrothermal synthesis of pore-expanded hydroxyapatite for enhanced Cu2+ adsorption from aqueous solutions

This paper describes the hydrothermal synthesis of a pore-expanded hydroxyapatite (PE-HAp) from fine–grained calcareous sludge using a cetyltrimethylammonium bromide (CTAB) as a template and 1,3,5-trimethylbenzene (TMB) as a pore expander for the removal of Cu2+ ions from aqueous solutions. The PE-HAp was characterized using XRD, SEM, DTA/TGA and BET surface analysis. Adsorption behavior was assessed using Langmuir, Freundlich, Dubinin–Radushkevich, Temkin and Sips isotherms. In a solution with an initial Cu2+ concentration of 200 mg L-1 and a pH of 5.0, the highest Cu2+ removal efficiency was achieved using PE-HAp synthesized at a hydrothermal temperature of 180 °C at a concentration of 15 g/L over a period of 60 min. Using Langmuir isotherms, the highest single-layer adsorption capacity value was 9.90 mg g-1. Gibbs free energy (ΔG°), changes in enthalpy (ΔH°), and changes entropy change (ΔS°) revealed that the adsorption of Cu2+ on PE-HAp was spontaneous and exothermic. The PE-HAp synthesized in this study is a promising material for the removal of Cu2+ from aqueous solutions.

Preparation of Nanosized Copper–Manganese Composite Oxides and Their Catalytic Performance in the Oxidation of Toluene

Nanosized Cu–Mn composite oxide catalysts were prepared from potassium permanganate, copper nitrate, n-butanol, and cetyltrimethylammonium bromide as a manganese source, copper source, reducing agent, and surfactant, respectively. The Cu[Formula: see text]–Mn sample possessed a small particle size (10–40[Formula: see text]nm) and a relatively high specific surface area ([Formula: see text]); its main components were Cu[Formula: see text]Mn[Formula: see text]O4 and Mn3O4. As a consequence, the Cu[Formula: see text]–Mn catalyst exhibited good catalytic activity in the oxidation of toluene. At a toluene concentration of 1000[Formula: see text]ppm and a space velocity of [Formula: see text], the [Formula: see text] and [Formula: see text] of the Cu[Formula: see text]–Mn catalyst toward toluene were 239[Formula: see text]C and 250[Formula: see text]C, respectively. Furthermore, even after 30[Formula: see text]h of operation at 275[Formula: see text]C, the conversion of toluene was 99% (at the space velocity of [Formula: see text]).

Amphipathic Surfactant on Reconstructed Bismuth Enables Industrial-Level Electroreduction of CO2 to Formate.

Developing efficient electrocatalysts for selective formate production via the electrochemical CO2 reduction reaction (CO2RR) is challenged by high overpotential, a narrow potential window of high Faradaic efficiency (FEformate), and limited current density (Jformate). Herein, we report a hierarchical BiOBr (CT/h-BiOBr) with surface-anchored cetyltrimethylammonium bromide (CTAB) for formate-selective large-scale CO2RR electrocatalysis. CT/h-BiOBr achieves over 90% FEformate across a wide potential range (-0.5 to -1.1 V) and an industrial-level Jformate surpassing 100 mA·cm-2 at -0.7 V. In situ investigations uncover the reconstructed Bi(110) surface as the active phase, with CTAB playing a dual role: its hydrophobic alkyl chains create a CO2-enriching microenvironment, while its polar head groups fine-tune the electronic structure, fostering a highly active phase. This work provides valuable insights into the role of surfactants in electrocatalysis and guides the design of electrocatalysts for the large-scale CO2RR.

Effect of surfactants on the permeation rate and selectivity of polyamide composite membranes for organic solvent nanofiltration

Solvent-resistant membranes are pivotal in industrial separations. This study aims to develop thin-film composite polyamide (TFC-PA) membranes with enhanced organic solvent nanofiltration (OSN) capabilities. Polyallylamine hydrochloride (PAAH) was used as the aqueous amine and isophthaloyl chloride (IPC) as the crosslinker to form the polyamide active layer by interfacial polymerization (IP) on a polyacrylonitrile (PAN) support. The impact of using anionic sodium dodecyl sulfate (SDS) and cationic cetyltrimethylammonium bromide (CTAB) to act as phase transfer agents during IP was investigated to understand their potential for facilitating the transfer of PAAH to the organic phase for reaction with IPC. The SDS and CTAB were separately dissolved into the PAAH solutions before IP to evaluate their effects on membrane properties. Extensive characterization including SEM, EDX, AFM, Water Contact Angle, ATR-FTIR, and Solid (CP-MAS) 13C NMR revealed various chemical and structural features of the membrane. The membrane M2 (PAAH-IPC) (exhibited >98% rejection for various anionic and cationic dyes. The inclusion of SDS during interfacial polymerization led to a substantial 3-fold increase in methanol permeate flux from 31 L m−2 h−1 to 119 L m−2 h−1, at a pressure of 15 bar. Conversely, the addition of CTAB resulted in membranes with higher permeate flux but insufficient dye rejection. Moreover, after three weeks of static aging of the membranes no significant changes were detected in either permeability or solute rejection, substantiating the stability of membranes.

Characterization of aqueous foams of alkyl polyglycoside, GreenZyme, alpha-olefin sulfonate, and cetyltrimethylammonium bromide in the presence of divalent ions

In this study, the impacts of divalent ions (calcium and magnesium) on aqueous foam stability and its rheological properties are investigated. A biodegradable surfactant of alkyl polyglycoside, (APG) and a commercial enzyme (GreenZyme, GZ) are used and their performance were compared with synthetic surfactants of alpha-olefin sulfonate (AOS) and cetyltrimethylammonium bromide (CTAB). The findings of the study revealed that the stability of all foams decreased with increasing concentrations of divalent ions, GZ recorded the lowest foam stability in the presence of the two ions and precipitation occurred in the AOS solution. On the other hand, foams generated by APG achieved the highest stability and the foams generated by CTAB showed the second highest stability among the foaming agents. Through rheological analyses, APG and CTAB exhibited shear thinning behaviour and their behaviour were modelled using a power law model in which the model can incorporate the effects of temperature and salinity.