Cetyltrimethylammonium Bromide Research Articles

Water-soluble chitosan polymer for enhanced oil recovery in the carbonate reservoir

Numerous surfactants, nanoparticles and polymers have been developed and utilized for enhanced oil recovery applications, irrespective of their environmental impact. Most of these oilfield chemicals were prepared through multi-steps from fossil-based starting materials using hazardous solvents. However, there is a desire to advance eco-friendly and sustainable materials to reduce CO2 emissions and enhance the sustainability of oil production. Herein, we propose the development of chitosan salt, a solely green polymer, prepared in water in the presence of acetic acid (0.1% v/v). The resulting water-soluble polymer demonstrated excellent stability under reservoir conditions and was tested for enhanced oil recovery in the carbonate reservoir. The oil-wet rock wettability was significantly reduced after using chitosan salt solution. Nuclear magnetic resonance (NMR) experiments were used to show the oil displacement at different pores regions using relaxation time (T2 distribution). Imbibition and coreflooding experiments showed that the chitosan salt is able to increase the enhanced oil recovery by extra 16.2% which surpass the recovery obtained from commercial surfactants such as α-olefin sulfonate (AOS) and cetrimonium bromide (CTAB). This study shows that green materials are promising candidates for oil recovery and upstream applications.

Slow release of surfactant by smart thermosensitive polymer-functionalized mesoporous silica for enhanced oil recovery: Synthesis and characterization

The efficiency of surfactant flooding can be improved through slow-release technology, which enables stimuli-sensitive and gradual release of surfactant. In this study, we synthesized a novel nanocomposite capsule composed of mesoporous silica functionalized with thermosensitive poly N-vinyl caprolactam (PNVCL). Well-optimized nanocarriers were synthesized by conducting sensitivity analyses on key synthesis parameters such as pH, reaction duration, and hydrophobic phase, resulting in hydrodynamic diameters ranging from 47 to 109 nm. Characterization of the nanocarrier structure was performed using dynamic light scattering (DLS), Brunauer–Emmett–Teller (BET) analysis, and field emission scanning electron microscopy (FESEM), while Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and energy-dispersive X-ray spectroscopy (EDS) were employed to analyze the nanocarrier composition. Poly N-vinyl caprolactam (NVCL)-functionalized mesoporous silica exhibited high surfactant loading (approximately 52 % w/w) and a large specific surface area (542.88 m2/g), featuring ink-bottle pores. Additionally, it demonstrated thermosensitive behavior, with the lower critical solution temperature of 39 °C. Gradual release of cetyltrimethylammonium bromide (CTAB) was observed in both deionized water and formation brine, with release rates increasing with temperature. Overall, the synthesized nanocomposite carrier holds significant potential as an ideal candidate for effectively controlling the release of surfactants in reservoirs subjected to high-temperature and high-salinity conditions.

Tailoring polypyrrole morphology and electronic properties through CTAB-SDS self-assembly

This study explores the polymerization of polypyrrole (PPy) within a self-assembled catanionic surfactant composed of cetyltrimethylammonium bromide (CTAB) - sodium dodecyl sulfate (SDS), aiming to control its morphology and electronic properties. The research systematically investigates how varying the compositions of CTAB and SDS surfactants influence the structural and electronic characteristics of PPy. Our findings indicate that the surfactant composition predominantly impacts the shape of PPy rather than its crystallinity. Despite the absence of significant crystallinity, variations in surfactant composition notably alter the electronic properties of PPy. Specifically, an increase in CTAB content results in electrical conductivity increasing from 0.34 to 0.01 S/m. Conversely, higher SDS content enhances the bipolaron-to-polaron ratio, particularly in the C−H deformation region, contributing to improved electronic characteristics. Additionally, packing density analysis reveals that the ordered or disordered acyl chain arrangement within the catanionic surfactant system varies significantly with surfactant composition, further influencing the morphology and electronic properties of PPy. These findings provide valuable pave for designing conductive polymers with tailored electronic properties by a catanionic surfactant, where precise control over such properties is crucial.

Engineering interfacial molecular interactions on Ag Hollow fibre gas diffusion electrodes for high efficiency in CO2 conversion to CO.

The electrochemical CO2 reduction reaction (CO2RR) occurs at the nanoscale interface of the electrode-electrolyte. Therefore, tailoring the interfacial properties in the interface microenvironment provides a powerful strategy to optimise the activity and selectivity of electrocatalysts towards the desired products. Here, the microenvironment at the electrode-electrolyte interface of the flow-through Ag-based hollow fibre gas diffusion electrode (Ag HFGDE) is modulated by introducing surfactant cetyltrimethylammonium bromide (CTAB) as the electrolyte additive. The porous hollow fibre configuration and gas penetration mode facilitate the CO2 mass transfer and the formation of the triple-phase interface. Through the ordered arrangement of hydrophobic long-alkyl chains, CTAB molecules at the electrode/electrolyte interface promoted CO2 penetration to active sites and repelled water to reduce the activity of competitive hydrogen evolution reaction (HER). By applying CTAB-containing catholyte, Ag HFGDE achieved a high CO Faradaic efficiency (FE) of over 95 % in a wide potential range and double the partial current density of CO. The enhancement of CO selectivity and suppression of hydrogen was attributed to the improvement of charge transfer and the CO2/H2O ratio enhancement. These findings highlight the importance of adjusting the local microenvironment to enhance the reaction kinetics and product selectivity in the electrochemical CO2 reduction reaction CO2RR.

Electrochemical Determination of 2,4-Dichlorophenol in Industrial Wastewater Using Bimetallic Metal-Organic Framework (MOF) Functionalized Graphene Oxide (GO) and Cetyltrimethylammonium Bromide (CTAB)

This study reports a sensor using a bimetallic metal-organic framework combined with 1,3,5-benzenetricarboxylic acid (BTC) (ZrCuBTC MOFs) functionalized graphene oxide (GO) and cetyltrimethylammonium bromide (CTAB) to determine the concentration of 2,4-dichlorophenol (2,4-DCP) in industrial wastewater. ZrCuBTC/GO was cast on a bare glassy carbon electrode followed by CTAB for analyte adsorption to produce the CTAB/ZrCuBTC/GO@GCE. The ZrCuBTC/GO was characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD), and N2 adsorption–desorption analysis. The electrochemical properties of these materials and 2,4-DCP on the CTAB/ZrCuBTC/GO were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The ZrCuBTC/GO had particle sizes from 20 to 40 nm, a pore diameter of 2.71 nm, a pore volume of 0.793 cm3 g−1, and a surface area of 1227 m2 g−1. Under the optimized conditions, the sensor had excellent electrocatalytic activity and high selectivity for 2,4-DCP. Linear ranges from 0.01 to 0.1, 0.1 to 1.5, and 1.5 to 30 µM were obtained with a low detection limit of 8 nM and excellent reproducibility of 2.71%. Wastewater before and after spiking was analyzed using the sensor and high-performance liquid chromatography (HPLC). The results were comparable with recoveries from 94.9 to 110.3 and 88.6 to 100.2%, respectively. Therefore the developed approach was suitable for the determination of 2,4-DCP in environmental samples.

Surface, micellization, and thermodynamic behavior of cetyltrimethylammonium bromide in sodium polystyrene sulfonate with and without methyl red in water–ethanol mixed solvent media at varying temperatures: A tensiometric analysis

In this study, we aim to systematically investigate the surface, micellization, and thermodynamic properties of Cetyl Trimethyl Ammonium Bromide (CTAB) in Sodium Polystyrene Sulfonate (NaPSS) solutions with and without methyl red (MR) dye in water–ethanol mixed solvent media (0, 0.1, 0.2, and 0.3 vol fraction of ethanol at 298.15 ± 0.2 K, 308.15 ± 0.2 K, and 318.15 ± 0.2 K. By employing surface tension measurements, we seek to uncover the effects of solvent composition, temperature, polyelectrolyte presence, and dye addition on the Critical Micelle Concentration (CMC) and other key surface and thermodynamic parameters. The CMC, slope (dγdlnC), and γCMC values determined from γ versus ln [CTAB] for the CTAB + NaPSS + MR diminish in contrast to the CTAB + NaPSS in the chosen solvent and the temperature range studied. However, with a rising temperature and ethanol volume fraction, the CMC value rises while the obtained γCMC values fall. Various surface and thermodynamic parameters like γCMC,Amin,Γmax, ΠCMC, adsorption efficiency (PC20), packing parameter (P), aggregation number (Nagg), micellization Gibbs’ energy (ΔGm0), adsorption of Gibbs’ energy (ΔGads0), effective Gibbs’ energy (ΔGeff0), minimum Gibbs’ energy (ΔGmin), and many other parameters have been determined, comparatively discussed, and analyzed for CTAB + NaPSS and CTAB + NaPSS + MR systems. This research provides a deeper understanding of the fundamental behaviors of these complex systems, their stability, and their feasibility, with potential implications for their practical applications in fields such as drug delivery, wastewater treatment, and the formulation of personal care products.

Stacking in electrophoresis by electroosmotic flow-assisted admicelle to solvent microextraction.

An in-line sample concentration method for capillary electrophoresis called admicelle to solvent microextraction was proposed. In this technique, analytes were trapped in the cetyltrimethylammonium bromide admicelles formed in situ on the negatively charged capillary surface. A solvent plug was then partially injected hydrodynamically to collapse the admicelles, which liberated and focused the analytes at the solvent front. Voltage was applied across the capillary, completing the stacking process. Various solvents, namely, methanol, ethanol, and acetonitrile, were investigated. The optimal solvent for solvent to admicelle microextraction was 30% acetonitrile in 24mM sodium tetraborate (pH 9.2). Sample injection time and solvent to sample injection ratio were also optimised. For this demonstration, the optimum sample injection time and solvent to sample injection ratio were 320s and 1:2, respectively. Using the optimum conditions, UV detection sensitivity was enhanced 132-176-fold for the model anions. The LOQ, %intra-/inter-day (n = 6/n = 12, 2days) repeatability, and linearity (R2) of admicelle to solvent microextraction were 0.08-2µg/mL, 1.9-3.9%, 2.8-4.9%, and 0.992, respectively. Admicelle to solvent microextraction was applied to the analysis of various fortified water samples, with good repeatability (%RSD = 0.5-3.6%), and no matrix interferences.

Waste Tea as Absorbent for Removal of Heavy Metal present in Contaminated Water

The goal of this study is to investigate the efficacy of tea-derived absorbents for the removal of heavy metals from contaminated water. For this, absorbents were prepared from milk tea (MT) waste, Ilam tea (IT) waste, and various types of tea leaves, including Immature (IML), mature (ML), and old leaves (OL). The characterization of the absorbents revealed distinct physical and chemical properties from X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), with varying degrees of effectiveness observed across different absorbent types. Heavy metal removal efficiency was assessed using a chemical-free UV-spectrophotometer. The results show that the maximum removal efficiency for Cd using the IT absorbent reaches up to 82.14% with 100 ppm cetyltrim ethylammonium bromide (CTAB), while the minimum removal efficiency is 32.14% using the OL absorbent with 20 ppm CTAB. For Zn, the OL absorbent demonstrates a maximum removal efficiency of 52.59% with 100 ppm CTAB, whereas the minimum efficiency is 3.70% using the ML absorbent with 20 ppm CTAB. For Ni, the highest removal efficiency is achieved with the ML absorbent, reaching up to 97.73% with 100 ppm CTAB, and the lowest is 31.82% with the MT absorbent with 20 ppm CTAB. The addition of a catalyst further enhanced removal efficiencies in both absorbents and metals. Also, the removal of heavy metal ions using 0.05 g of tea absorbent combined with CTAB at varying concentrations. Results show that the addition of 20 ppm and 100 ppm CTAB significantly reduces metal ion concentrations from an initial 100 mg/L. The metal ion concentration decreases as CTAB concentration increases, demonstrating the effectiveness of CTAB in enhancing the absorption capacity of tea absorbent for heavy metal removal. The investigation of selective adsorption of Ni, Zn, and Cd by an adsorbent, revealing competitive adsorption behavior with Ni and Zn being adsorbed more rapidly than Cd, suggesting the impact of metal ion interference on adsorption efficiency. However, limitations were observed with certain absorbent types; for instance, immature leaves did not effectively remove Ni. Overall, this study underscores the potential of tea-derived absorbents as sustainable solutions for mitigating heavy metal pollution in industrial wastewater. Further research is needed to optimize absorbent formulations and explore their applicability in real-world environmental remediation scenarios.

Multi-scale evaluation of surfactant effects on asphalt desorption behavior from oil sand surfaces

This study created a hydrophobic oil sand model to investigate the impact of surfactants on the desorption behavior of asphalt from solid surface. Cationic surfactant cetyl trimethyl ammonium bromide (CTAB) and anionic surfactant sodium dodecyl benzene sulfonate (SDBS) were used to soak the model to observe the effect of surfactants on asphalt desorption. The effect of surfactant pretreatment on the wettability of the substrate was evaluated by measuring the contact angle of ultrapure water on the substrate and observing the morphological changes of the solid surface by atomic force microscopy. The results show that the contact angle of the model treated with SDBS decreases to 10° after 3 days, which significantly improves the wettability of the substrate surface and promotes the desorption of asphalt. However, CTAB has no obvious effect on asphalt desorption. The standard deviation of the gray value of the sand surface image is significantly reduced to 38.693 after the SDBS treatment, which can be seen by binarizing the image. This suggests that the asphalt and solution are evenly distributed and that there is hardly any discernible boundary. Nevertheless, neither of the two surfactants can improve the water-based extraction efficiency of oil sands after soaking treatment. The asphalt yield is less than 5% after 30 days of pretreatment with CTAB solution, while only 45% asphalt yield is obtained after 30 days of pretreatment with SDBS solution. Despite these variations, the quality of asphalt foam remains relatively the same. This may be related to the failure of surfactants to improve the surface wettability of hydrophobic sand. Therefore, the surface wettability of the sand is considered to be a key factor affecting the asphalt desorption and final yield. This study can provide a scientific basis for oil sand recovery to a certain extent.

Nanobubble-enabled foam fractionation to remove algogenic odorous micropollutants

Due to climate change and environmental pollution, natural lakes and reservoir water suffer increasingly serious algal blooms and associated water quality problems due to the presence of algal or algogenic organic matter (AOM) such as algal odour and toxins. Effective removal of these micropollutants, especially in the event of algal blooms, is critical to aesthetic values of water bodies, drinking water security and human health. The study investigated the removal efficiency of two common odorous compounds, trans-1,10-dimethyl-trans-9-decalol (geosmin) and 2-Methylisoborneol (2-MIB), using foam fractionation enabled by air nanobubbles with addition of two common cationic and anionic surfactants, sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB), to enhance foaming ability and stability. The results showed that the cationic surfactant (i.e., CTAB), a low pH, and high ionic strength significantly promoted the removal of geosmin and 2-MIB. For example, the removal tests using the synthetic water determined that the conditions of pH = 7, [CTAB] = 20 mg·L−1 and IS = 10 mM as NaCl resulted in both the highest geosmin removal rate of 91.81% and highest 2-MIB removal rate of 85.0%. The removal of two odorous compounds in real lake water was evaluated, which yielded removal rates of 83.2% for geosmin and 48.1% for 2-MIB, highlighting the minor inhibition from water matrixes on the removal performances. Compared to microbubbles, nanobubbles enabled greater surface areas of foam and higher removal efficiencies. The study provided new insights into the use of foam fractionation with air nanobubbles to enhance the removal of odorous compounds from impaired water and mitigate the negative environmental and health impacts of harmful algal blooms (HABs).

Structural modification of mesoporous lanthanum oxide into 3D coral-like and nano needle-like structure for effective broadband microwave absorbing materials☆

Structural modification of three dimensional (3D) materials for the application of dielectric loss-based microwave absorbing materials (MAMs) usually relies on intricate synthesis process and can pose challenges in terms of scalability and mass production for practical application. In this work, we reported a successful attempt in modifying the 3D structure of mesoporous lanthanum oxide (La2O3) for effective broadband MAMs candidate via simple co-precipitation process. The inclusion of cetyl-trimethylammonium bromide (CTAB) and hydrothermal aging treatment result in a significant transformation of La2O3 particles from their original polygonal form to a 3D coral-like and nano needle-like structure. The utilization of CTAB and hydrothermal aging results in the increase of surface area and a two-fold increase in pore volume of the resulting La2O3. Due to its unique 3D structure, the 3D coral-like and nano needle-like La2O3 materials possess a broadband electromagnetic (EM) wave absorption characteristic with the effective absorption bandwidth (EAB) covering the C-band frequency range. Specifically, in the La2O3 C-H sample (with CTAB – with hydrothermal), it exhibits strong EM wave absorption with a reflection loss (RL) value of –33.07 dB which equals to 99.95% EM wave absorption at a thickness of only 1.50 mm. The detailed analysis of EM wave absorption properties reveals that the improvement of La2O3 materials to attenuate EM wave energy arises from the dielectric loss phenomenon, the enhanced interfacial polarization, multiple reflections mechanism, and conduction loss mechanism induced by the 3D structural formation of the La2O3 structure. This work proposes a novel and efficient approach in synthesizing and modifying 3D materials for effective broadband EM wave absorption.

Synthesis, Characterization, and Interaction Studies of Naphtho‐[2,3]‐furan‐Based Molecules with CTAB as Model Surfactant

AbstractThe synthesis of highly sensitive UV–visible active naphthofuran derivatives, namely naphtho‐[2,3]‐furan‐3‐yl acetate (NF), 9‐bromonaphtho‐[2,3]‐furan‐3‐yl acetate (BNF), 9‐nitronaphtho‐[2,3]‐furan‐3‐yl acetate (NNF), 9‐iodonaphtho‐[2,3]‐furan‐3‐yl acetate (INF), and naphtho‐[2,1‐b]‐furan‐4‐carboxylic acid (ONF) as solvatochromic molecules, was carried out through multistep synthetic approach. These molecules possess different substituents that tend to form micelles in cetyl trimethylammonium bromide (CTAB) aqueous system. During the micellization process, the absorption spectrum of the synthesized molecule exhibits sensitivity towards the polarity of the environment, which affects the critical micelle concentration (cmc) of CTAB. This study demonstrates that synthesized molecules can be used for estimating solvent polarity and cmc.

Synergistic antimicrobial effect of daptomycin and ethyl lauroyl arginate containing self-emulsifying drug delivery system against bacterial infections

This study aimed to enhance the antimicrobial properties of daptomycin by ion-pairing with ethyl lauroyl arginate (ELA) and incorporation in a self-emulsifying drug delivery system (SEDDS).Daptomycin was ion-paired with the ELA and the hydrophobic ion pair (HIP) was loaded into SEDDS. SEDDS 1 consisted of 15% oleic acid, 5% soy phosphatidylcholine, 10% cetyltrimethylammonium bromide (CTAB) in medium-chain triglycerides (MCT) at a concentration of 250 mg/ml, 20% benzyl alcohol, and 50% PG-4 caprate. SEDDS 2 comprised 10% soy phosphatidylcholine in MCT at a concentration of 53 mg/ml, 10% CTAB, 20% benzyl alcohol, and 60% PG-4 caprate. SEDDS were characterized regarding droplet size, polydispersity index (PDI), zeta potential, and stability. Cytotoxicity was evaluated on Caco-2, HeLa, and SW620 cells. Antimicrobial activity was assessed by agar diffusion studies and time-kill assays with Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Candida albicans.Both formulations showed a droplet size below 200 nm with a PDI < 0.4, a positive zeta potential, and robust thermodynamic stability. They exhibited low toxicity profiles while maintaining full antimicrobial efficacy on all tested pathogens. Compared to unformulated daptomycin, SEDDS 1 and 2 lowered the minimum inhibitory concentration (MIC) 5- and 8- fold for S. aureus and 10- and 30- fold for S. epidermidis, respectively. Bacterial killing time was 105 -fold shortened with SEDDS 1 and 106 -fold with SEDDS 2. Furthermore, HIP and SEDDS enhanced antibacterial activity against Candida albicans and Pseudomonas aeruginosa. According to these results, ion pairing of daptomycin with ELA and incorporation into SEDDS is a promising approach to improve the antimicrobial activity of this drug.

Enhanced powder characteristics of succinic acid through crystallization techniques for food industry application

During crystallization, succinic acid, an important food additive, exhibit severe agglomeration behaviour, uneven crystal size distribution (CSD), and irregular crystal morphology, resulting in poor powder flow properties. This paper presents an innovative approach to optimize succinic acid crystallization through investigation of novel blade milling method, seeding, and inclusion of green additive, cetyltrimethylammonium bromide (CTAB). CTAB for crystal habit regulation and formation of desired cubic-like morphology. We employ Mask R-CNN, a deep learning-based image analysis tool to quantitatively assess crystal and powder flow properties. Results demonstrate that the inclusion of 0.5 wt% CTAB with two-stage cooling method yields uniform CSD ranging from 30 μm to 160 μm and improves powder properties, reducing the agglomeration degree by 46% and caking ratio to only 6.78%, indicating a decreased tendency for clumping. The integration of crystallization with the proposed deep learning framework not only improves succinic acid food functionality but also showcases highly efficient method for optimizing crystal properties, setting new standard for food crystallization processes. It has been adequately presented with real-time high-precision analysis of CSD, agglomeration, etc, facilitating rapid screening for optimized food quality improvements.

Wet-chemical preparation and physicochemical characterization of nanostructured Zn-Bi2O3/CeO2 composite: A visible-light-driven catalyst for the annihilation of pharmaceutical pollutant

A modified co-precipitation technique assisted with cetyltrimethylammonium bromide (CTAB) surfactant was used to synthesize a nanostructured and zinc-doped mixed metal oxide (Zn-Bi2O3/CeO2) composite. Using X-ray diffraction (XRD), the synthesized nanocomposite was studied in terms of its crystal structure, grain size, percentage crystallinity, and percentage porosity. Energy dispersive X-ray elemental analysis (EDX) was used to ascertain the chemical composition, SEM to confirm the creation of nanostructure material, and Fourier transform infrared spectroscopy (FTIR) to extract the existing functional groups. Investigation of light harvesting properties (UV/Vis) and thermogravimetric analysis (TGA) reveals that the doped composite exhibits a band gap driven by visible light and remarkable thermal stability at high temperatures. The pH value at which a material's net charge is zero, known as pHpzc, is 7.93 for the doped mixed metal oxide composite. The Zn-Bi2O3/CeO2 nanocomposite effectively eliminates 98.4 percent of the quinolone antibiotic (levofloxacin) via a mechanism that integrates sorption and photocatalytic degradation induced by visible light. To determine the optimal circumstances for the efficient operation of a photocatalyst, we experimented with different time intervals, beginning drug concentrations, catalyst dosages, operating temperatures, and pH levels. Reusability tests and post-activity FTIR analysis were used to investigate the long-term usability and structural stability of the newly developed doped composite photocatalyst. The scavenging tests revealed a potential photocatalytic mechanism to explain the annihilation of the levofloxacin drug on the synthesized catalyst. The physicochemical and photocatalytic evaluations recommend that the assembled integrated material has excellent potential for mineralizing medicinal products in pharmaceutical wastes.

Relaxometric properties and biocompatibility of a novel nanostructured fluorinated gadolinium metal-organic framework.

A novel Gd-MOF based on tetrafluoro-terephthalic acid has been synthesized and its structure has been solved using X-ray single crystal diffraction data. The compound, with the formula [Gd2(F4BDC)3·H2O]·DMF, is isostructural with other Ln-MOFs based on the same ligand and has been recently reported. Its crystals were also reduced to nanometer size by employing acetic acid or cetyltrimethylammonium bromide (CTAB) as a modulator. The relaxometric properties of the nanoparticles were evaluated in solution by measuring 1H T1 and T2 as a function of the applied magnetic field and temperature. The biocompatibility of Gd-MOFs was evaluated on murine microglial BV-2 and human glioblastoma U251 cell lines. In both cell lines, Gd-MOFs do not modify the cell cycle profile or the activation levels of ERK1/2 and Akt, which are protein-serine/threonine kinases that participate in many signal transduction pathways. These pathways are fundamental in the regulation of a large variety of processes such as cell migration, cell cycle progression, differentiation, cell survival, metabolism, transcription, tumour progression and others. These data indicate that Gd-MOF nanoparticles exhibit high biocompatibility, making them potentially valuable for diagnostic and biomedical applications.

Effect of surface charge on laser-produced silver nanoparticles for dye reduction and surface-enhanced Raman spectroscopy

Silver nanoparticles (Ag NPs) are widely used in biological, chemical, and physical fields due to their distinct properties. However, the effect of surfactants with different polarities on the catalytic and surface-enhanced Raman spectroscopy (SERS) performance of Ag NPs has not been thoroughly studied. Here, we tailor the surface charge of laser-synthesized Ag NP without changing their morphology and investigate their catalytic and SERS capabilities. The surfactant-free silver nanoparticles (NPBare), synthesized via pulsed laser ablation in liquid (PLAL), are subsequently coated with ionic surfactants sodium dodecyl sulfate (NPSDS) and cetyltrimethylammonium bromide (NPCTAB). The synthesis and morphology of Ag NPs are confirmed using UV-Vis absorption spectroscopy and scanning electron microscopy. The surface charge of fabricated NPs is determined using zeta potential (ZP) measurements. The ZP values of NPBare, NPSDS, and NPCTAB are determined to be -17 mV, 28.7 mV, and 5.58 mV, respectively. The catalytic activity of bare and coated Ag NPs was tested against the cationic and anionic dyes, Methylene blue (MB) and Methyl orange (MO) respectively. The reduction rate of both dyes was highest when using NPBare. However, in the case of coated nanoparticles, the rate of MB and MO reduction depends on the difference between the ZP of the dye and nanoparticles: the rate of reduction increases with the difference between the zeta potentials of the dye and coated nanoparticles increases. The SERS capability of bare and coated NPs was evaluated for anionic (MO) and cationic (MB, Rhodamine B, and Crystal Violet) dyes. The SERS intensity of dyes strongly enhanced with the increase in ZP difference between the dye molecules and NPs. Surface charge modified NPs shown excellent SERS sensitivity with detection limit up to nanomolar for dye molecules as well as the homogeneity of NPs demonstrated in Raman mapping results with relative standard deviation of 17%. The results suggest that the electrostatic interaction between the nanoparticles and dye molecules plays a dominant role in SERS enhancement. These findings highlight the significance of surface charge in improving the catalytic and sensing properties of noble metal nanoparticles.

Effect of solvent and temperature on the micellization and thermophysical properties of cetyltrimethylammonium bromide

The Micellization is the fundamental phenomenon in colloid and surface chemistry which plays a pivotal role in a multitude of industrial processes, biological systems, and everyday applications. In this study, we investigate the micellization behavior of the cationic surfactant, cetyltrimethylammonium bromide (CTAB) within aqueous and ethanol–water mixtures across a temperature range. The electrical conductivity measurements unveil insights into the critical micelle concentration (CMC) and the degree of counterion dissociation (β) at each temperature. Notably, as ethanol content increases in the solvent, both CMC and β values exhibit a corresponding uptick. These findings enable the assessment of standard Gibbs free energy (ΔGmic0). Furthermore, our investigation extends to find out the thermophysical properties (viz., density, dynamic viscosity, and kinematic viscosity) assessments across varying ethanol compositions and temperatures. These metrics facilitate the calculation of activation energy for mixed systems. The implications of these results (data) could be useful for both the fundamental as well applied research, and promise valuable insights for future endeavors.

Evaluation of CO2 storage properties and mobility through NMR technique in post-grafting synthetized organically functionalized porous silica

Functionalized porous silica materials were synthesized in alkaline conditions by post-grafting method using hexadecyltrimethylammonium bromide (CTAB) as templating agent, tetraethyl orthosilicate (TEOS) as silica precursors and trialkoxysilanes functionalised with different organic groups. Textural features, halfway between microporosity and mesoporosity, combined with the surface physico-chemical ones related to various organic groups, determined different CO2 storage properties highlighting a strong interaction with the precursor 3-Aminopropyl)triethoxysilane. NMR spectroscopy also showed how physisorption is the mainstream mechanism for CO2 adsorption in all the sorbents, except for the aforementioned organic group in which an important chemisorption contribution occurs. Diffusion and molecular mobility analysis revealed that at least two species coexist within the micro-/meso-pores of the sorbents, namely, CO2 molecules powerfully interacting with the pore surface (pore-surface CO2) and “bulk-like” CO2 filling the central region of the pores. Furthermore, the post functionalization suppresses the diffusion of CO2 molecules through the pore channels with all the functionalized materials exhibiting a single self-diffusion coefficient. On the other side, D// strictly depends on the average pore size of the sorbent.

Structure-directing agent mediated synthesis of SnS2 coupled with UltrapheneTM as highly stable anode material for sodium-ion battery

Sodium-ion battery (SIB) with abundant resources has been intensively developed as the efficient energy storage device. Tin disulfide (SnS2) is one of the attractive anode materials due to its high capacity and two-dimensional structure. Nevertheless, volume expansion and low conductivity result in the poor rate performance and stability. In this study, three strategies are applied to design efficient SnS2-based anode materials for the SIB. Two precursor solvents of deionized water (DIW) and ethanol and one structure-directing agent of cetyltrimethylammonium bromide (CTAB) are incorporated to synthesize SnS2. The commercial UlrapheneTM is further mixed with SnS2 to design composites (U/s-SnS2) with different ratios. The optimal SnS2 and U/s-SnS2 anodes respectively show the specific capacities of 187.7 and 326.3 mAh/g at 1.6 A/g. After 100 cycles, the U/s-SnS2 anode still attains specific capacities of 308.7 and 438.9 mAh/g at 1.0 and 0.1 A/g corresponding to capacity retentions of 74.5 % and 80.1 %, respectively. The excellent rate performance and cycling stability of the U/s-SnS2 anode are attributed to the smaller charge-transfer resistance and the larger Na+ diffusion coefficient. This work successfully brings a blueprint for adopting several useful strategies to improve the electrochemical performance of SnS2. The effects for all parameters are also carefully explained.