Cetyltrimethylammonium Bromide Research Articles

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.

Fabrication and characterization of carvacrol encapsulated gelatin/chitosan composite nanofiber membrane as active packaging material

In this study, carvacrol was effectively encapsulated in gelatin/chitosan composite nanofiber membrane using the electrospinning method with the help of the cationic surfactant cetyltrimethylammonium bromide (CTAB). The effects of CTAB (0.0 %, 1 %, w/w) and bioactive carvacrol (0.0 %, 1.0 %, 3.0 %, 5.0 %, 7.0 %, 10 %, w/w) on the structural, physicomechanical, antibacterial, and antioxidant characteristics of the nanofiber membranes were investigated. The results demonstrated that the antibacterial and antioxidant characteristics of the gelatin/chitosan composite nanofiber membrane (GC) and GC-CAR membrane (with the addition of 1.0 % carvacrol) were unsatisfactory. As carvacrol and CTAB were both added, the elongation at break, antibacterial, and antioxidant properties of the nanofiber membranes significantly improved (p < 0.05), while the water vapor permeability (WVP) significantly decreased (p < 0.05). When the added amount of carvacrol was 5 % (w/w), the nanofiber membrane (GC-CAR5-CTAB) exhibited the best antioxidant and antibacterial performance. Finally, the GC-CAR5-CTAB membrane was applied to the preservation of strawberries and Erjingtiao chilies, and their shelf life was effectively extended. The above results indicate that the nanofiber membrane prepared in this study has great potential for application in food-active packaging.

Synergistic inhibition effect of thioureido imidazoline and cationic surfactants with different alkyl chain lengths on X80 carbon steel in CO2-satureted NaCl solutions

The corrosion inhibition performance of the thioureido imidazoline (TU-IM) corrosion inhibitor, along with three surfactants, was assessed for X80 carbon steels in a CO2-saturated NaCl solution using weight loss tests, electrochemical and microstructural characterization. Results demonstrate that the corrosion-inhibition efficiency of surfactants improves with increasing alkyl-chain length in the following order: cetyltrimethylammonium bromide (CTAB) > tetradecyltrimethylammonium bromide (TTAB) > dodecyltrimethylammonium bromide (DTAB). A synergistic corrosion inhibition effect between TU-IM and DTAB/TTAB was observed, with the best performance achieved using 10mg/L TU-IM and 10mg/L DTAB/TTAB (inhibition efficiency: 97.68%), which is mainly attributed to the cooperative adsorption of both substances. By contrast, the synergistic inhibition capability of TU-IM with the surfactants decreased as the alkyl-chain length increased, and even an antagonistic effect was noted for the combination of TU-IM + CTAB owing to the competitive adsorption between the surfactant and the corrosion inhibitor.

Lateral flow chromatography strip system for rapid fluorescence determination of phycocyanin in water samples

Phycocyanin (PC) is of great significance to biomedicine and water environmental safety. Hence, it is indispensable to develop facile and rapid method for PC determination. In this investigation, a system containing lateral flow chromatography (LFC) strip (which was deposited with molecularly imprinted polymer (MIP) capped CdTe quantum dots (QDs) based mesoporous structured coated silica nanoparticles, SiO2@QDs@ms-MIP NPs) and miniaturized fluorimeter was first fabricated. In detail, a two-step strategy was utilized for preparation of SiO2@QDs@ms-MIP NPs, which consisted of modification of CdTe QDs onto the silica NPs first, and synthesis of mesoporous imprinting shell by using PC as template molecule and cetyltrimethylammonium bromide (CTAB) as surfactant. After that, novel fluorescence NPs possessing specific recognition and sensitivity toward PC in seawater and lake water were acquired. The resulting fluorescent sensing system exhibited outstanding performances, which included excellent sensitivity (4.5 nmol/L), satisfactory specificity (imprinting factor, 2.31), appropriate linearity range (0.01~5 μmol/L), good recovery (96.0~101.7%), excellent stability (relative standard deviation, RSD<1.1%), wonderful reproducibility (RSD<1.1%), and excellent anti-interference ability. The results of the fluorescent sensing system were superior to those of the commonly used ultraviolet (UV) method. The proposed strategy showed great potential for fast (<10min) and convenient fluorescence detection of PC in real samples.

A new isolate of mungbean yellow mosaic India virus in Vigna mungo L. reported from a Dayalbagh field, Agra.

Black gram (Vigna mungo L.) plants showing yellow mosaic symptoms during 2019-2022 crop seasons were collected randomly from a Dayalbagh field, Agra Region of Uttar Pradesh, India. Total genomic DNA was isolated from the infected leaf samples by the Cetyltrimethylammonium bromide (CTAB) method and subjected to PCR. After viral confirmation, the viral genome was amplified by rolling circle amplification following the standard protocol. The DNA A and DNA B subgenomes were cloned individually as a PstI and BamHI fragment in the pUC18 vector. Positive clones were subjected to DNA sequencing. The results revealed that DNA A and DNA B show the closest nucleotide identity with "mungbean yellow mosaic India virus-[Mungbean], DNA-A, the complete sequence" (GeneBank Accession No AF416742.1) with 98.14% identity, and "mungbean yellow mosaic India virus isolate Mu1-Dholi segment DNA-B, the complete sequence" (GeneBank Accession No MW814723.1) with 97.94% identity, respectively. The new isolate of mungbean yellow mosaic India virus (MYMIV) shows sequence similarity with the coat protein gene of various strains of MYMIV. In the new isolate of MYMIV, a point mutation wasobserved at the 2036th nucleotide of DNA B, which disrupts the reading frame to introduce a stop codon and thus leading to a decrease in the size of the movement protein gene. In the present study we are reporting the whole genome sequence of the MYMIV Dayalbagh isolate for the first time.

Evaluation of DNA Extraction Methods for Microbial Community Profiling in Deadwood Decomposition.

As technologies advance alongside metabarcoding and metagenomic resources, particularly for larger fungal genomes, DNA extraction methods must be optimized to meet higher thresholds, especially from complex environmental substrates. This study focused on extracting fungal genomic compounds from woody substrates, a challenge due to the embedment of endophytic and saprotrophic fungi within wood cells, the physical recalcitrance of wood, the adsorption of nucleic acids to wood polymers, and the release of downstream inhibitors. Hypothesizing that cetyltrimethylammonium bromide would be the best option, we compared prominent methods by extracting and sequencing microbial DNA from sound and decayed birch (Betula papyrifera) and pine (Pinus resinosa). DNA quantities varied significantly depending on extraction methods and decay stage. The quality of DNA, in terms of purity and integrity, significantly impacted whether the samples could be amplified and sequenced. However, amplicon sequencing of bacterial and fungal communities revealed no significant extraction bias. This, along with the sequencing effectiveness and cost/time efficiency, indicates that Qiagen is the gold standard for woody substrates. This study increases confidence in published amplicon data sets regardless of the extraction methods, provides a cost-benefit table for making protocol decisions, and offers guidance on fungal DNA extractions from complex organic substrates (sound and decayed wood) that would best suit future metagenomic efforts.

Inhibition of the growth rate of ZnS anode crystal plane: boosting photocatalytic hydrogen production performance

The catalyst's particle size plays a crucial role in enhancing photocatalytic performance. However, it is still unclear to analyse the mechanism by which surfactants affect the particle size of photocatalysts from the perspective of crystal growth. Herein, ZnS nanomaterials with different particle sizes were synthesized using a simple solid-state chemical synthesis method, and the intrinsic influence mechanism between surfactant and catalyst particle size was analyzed from the perspective of crystal growth. It was discovered that the particle size of ZnS kept getting smaller due to changes in polyethylene glycol, cetyltrimethylammonium bromide, and sodium dodecyl sulfate. Analyzing the reasons revealed that the catalyst's particle size was related to the type of surfactant: anionic surfactants could reduce the catalyst size. Correspondingly, the catalyst with a smaller particle size has the optimal performance for photocatalytic hydrogen production. Photocatalysts Z-SDS exhibited outstanding photocatalytic performance, yielding 11.47 mmol/g of hydrogen after a five-hour illumination. Furthermore, the intrinsic influence mechanism between anionic and cationic surfactants, photocatalyst particle size, and catalytic performance was investigated. This investigation provides a new idea for synthesizing small-size and high-performance photocatalysts.

Modified Cellulose Nanocrystals Encapsulating Cannabigerol: A Step Forward in Controlling Intestinal Inflammatory Disorders

Cannabigerol (CBG) from Cannabis sativa L. is known for its anti-inflammatory, antibacterial, and antioxidant properties, showing potential against intestinal inflammation. However, its lipophilic nature limits its absorption and stability. Researchers have explored cellulose nanocrystals (CNCs) to deliver lipophilic compounds and enhance their biological outcomes. This study investigated the capability of modified CNC with cetyltrimethylammonium bromide (CTAB) to effectively deliver CBG. The encapsulation process’s impact on cytotoxicity, biological activity, and controlled release during digestion was assessed. Results indicated that CNC-CTAB encapsulation significantly reduced CBG’s cytotoxicity on intestinal cells, allowing safer administration of higher doses. The antioxidant and anti-inflammatory properties of the encapsulated CBG were retained, resulting in a decrease in reactive oxygen species and cytokine levels in intestinal cells. Additionally, the system inhibited the growth of the intestinal pathogen Campylobacter jejuni. The study supports using CNC-CTAB as an efficient delivery system to enhance CBG’s potential against intestinal inflammation. Incorporating this system into food matrices could lead to novel functional foods for managing intestinal inflammation.

Surface Modification of Cellulose Nanofiber (CNF) from Banana (&lt;i&gt;Musa paradisiaca&lt;/i&gt;) Pseudo-Stem with Cetyltrimethylammonium Bromide (CTAB)

Modifying cellulose nanofiber (CNF) is necessary to improve its hydrophobic properties for broader applications. The surface of CNF from the banana pseudo-stem (Musa paradisiaca) was modified using a cationic surfactant, Cetyltrimethylammonium Bromide (CTAB). Principally, CNF surface sulfate ester group counterions are substituted for cetyltrimethylammonium (CTA+), which acts as a bulky, amphiphilic cation. Three steps produce CNF from banana pseudo-stem: delignification, bleaching, and acid hydrolysis. The acid hydrolysis process was optimized by adjusting the concentration of sulfuric acid. A 50% sulfuric acid concentration produced CNF with a size of 118 nm and the highest stability of its zeta potential value of -28.4 mV. The hydrophobicity of CNF increased after CTAB modification, as demonstrated by a change in surface charge from -28.4 mV to +3.63 mV. The modified CNF50-CTAB had a contact angle of 45.5º. In addition, CNF50-CTAB was unstable in water and formed stable colloidal suspensions in chloroform.

Tailoring Natural and Fly Ash-Based Zeolites Surfaces for Efficient 2,4-D Herbicide Adsorption: The Role of Hexadecyltrimethylammonium Bromide Modification

Global development has led to the generation of substantial levels of hazardous contaminants, including pesticides, which pose significant environmental risks. Effective elimination of these pollutants is essential, and innovative materials and techniques offer promising solutions. This study examines the modification of natural zeolite (clinoptilolite) and fly ash-based NaA and NaX zeolites with hexadecyltrimethylammonium bromide (CTAB) to create inexpensive adsorbents for removing 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide from water. Detailed characterization of these materials was performed, along with an evaluation of the effects of pH, contact time, temperature, and initial 2,4-D concentration on their sorption capacities. The modified samples exhibited significant changes in elemental composition (e.g., reduced SiO2 and Al2O3 content, presence of Br) and textural properties. The adsorption of the pesticide was found to be an exothermic, spontaneous process of pseudo-second-order kinetics and was consistent with the Langmuir model. The highest sorption capacities were observed for samples modified with 0.05 mol L−1 CTAB, particularly for CliCTAB-0.05.

Investigation of the synergistic effects of SiO2 and Al2O3 nanoparticles with SDS and CTAB surfactants on the stability and improving phase behavior of water-oil emulsions

The stability of emulsions is a significant challenge across various industries, including food, pharmaceutical, and petroleum. Surface-active agents utilized for enhanced oil recovery often exhibit inadequate performance under reservoir conditions with high salinity, presenting a critical barrier to effective emulsion stabilization. Furthermore, due to the extreme hydrophilic or hydrophobic nature of nanoparticles (NPs), they are not effective in stabilizing emulsions on their own. To address this limitation, a minimal quantity of surfactant was introduced into the NPs to improve their wettability and achieve dual wettability. This research has examined the synergistic effects of SiO₂ and Al₂O₃ NPs combined with sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) surfactants on water-oil emulsion stability. This approach enhances emulsion stability by combining the stabilizing effects of both the NPs and the surfactants, an aspect that has not been previously addressed in phase behavior studies through the examination of the interactions and surface behavior of surfactant-nanoparticle complexes at the oil-water interface. Several experiments, including phase behavior, FT-IR, zeta potential, contact angle, and interfacial tension (IFT) tests, were performed to evaluate the interaction of surfactants with NPs. The results demonstrate that combining NPs with surfactants, especially those with opposite charges, significantly reduces IFT to the order of 10−6 mN/m, which can overcome capillary pressure, and enhances optimal salinity levels even up to 75000 ppm. Interactions between CTAB-SiO₂ and SDS-Al₂O₃ notably improve the hydrophobicity of NPs, resulting in IFT reductions of 11.4 and 7 mN/m, respectively, compared to NPs alone.

Comparison of Four Different DNA Isolation Methods from MGIT Culture for Long-Read Whole Genome Sequencing of Mycobacterium tuberculosis

Background: Tuberculosis (TB) remains a global health challenge, particularly due to drug resistance and limitations in rapid diagnosis. Next-generation sequencing (NGS), especially long-read whole genome sequencing (WGS), shows promise for rapidly detecting TB and drug resistance, but it requires high-quality DNA, which is difficult to extract from Mycobacterium tuberculosis due to its complex cell wall. Objectives: This study evaluated four DNA isolation methods for extracting pure DNA from M. tuberculosis, aiming to standardize protocols for long-read WGS. Methods: Mycobacterium tuberculosis H37RV colonies were grown in BACTEC MGIT liquid medium. Two pellets were prepared as the initial material for the DNA extraction protocol: Pellets from 1 mL McFarland 2 suspensions and all growing colonies from two MGIT liquid cultures. Four DNA extraction methods were used: The cetyltrimethylammonium bromide (CTAB) method, GeneJET Genomic DNA Purification Kit, Quick-DNA Fecal/Soil Microbe Kit, and Genematrix Tissue/Bacterial DNA Purification Kit, with some modifications. DNA quality was assessed based on concentration, purity, and integrity. Results: Among the tested methods, the Quick-DNA Fecal/Soil Kit yielded approximately 85 ng/mL of DNA and a purity of 1.9 at 260/280 nm from the colonial pellet of two MGIT tubes. However, lower intact DNA [DNA integrity number (DIN) ~ 6.8] was obtained with this kit. The CTAB method provided the highest intact DNA (DIN ~ 9.5), although the purity of the DNA was not sufficient. Conclusions: Based on three repetitions of McF-2 and colonial pellet extractions, the Quick-DNA Fecal/Soil Kit yielded the highest DNA quantity and purity but showed lower integrity compared to other methods, indicating the need for adjustments. A pellet from two MGIT cultures (~ 100 µL) is suitable for long-read WGS with this kit. However, a larger sample size is required to generalize these findings. For effective long-read sequencing of M. tuberculosis, DNA extraction protocols must be optimized to balance yield, fragment size, and purity for accurate sequencing and drug resistance analysis.

Dispersion and Stability Behaviour of Graphene and MWCNT Based Nano-Lubricant for Vapour Compression Refrigeration (VCR) System

Incorporating nanoparticles into oil compressors marks a significant advancement in scientific research. It has been widely demonstrated that the inclusion of nanoparticles can markedly improve the system's efficiency by reducing energy consumption, decreasing evaporator temperatures, and increasing condenser temperatures. Nanoparticles made of carbon, including those of metal, metal oxide, and metal hybrids, are particularly valued for their superior properties and are deemed to have considerable potential for achievements. This study focuses on examining the stability of graphene and multi-walled carbon nanotubes (MWCNT) in polyolester (POE) oil as a precursor to replacing conventional lubricating oil in refrigeration systems separately. Graphene nano-lubricants were tested at concentrations ranging from 0.1 to 0.3 g/L with the selected surfactant, cetyltrimethylammonium bromide (CTAB), in a 1:1 ratio, while MWCNT nano-lubricants were tested from 0.5 to 0.7 g/L. All samples were prepared using a two-step method that involved magnetic stirring at 1250 rpm for 45 minutes, followed by ultrasonication for 30 minutes. The samples underwent evaluation through three methods of observation. Initial visual observation was conducted immediately after production, then after a 24-hour settling period, and finally, after seven days, the three most optimal samples were identified. For MWCNT, an additional stability test was necessitated due to the high concentration levels, making it challenging to determine the three most stable concentrations. The UV-VIS spectrophotometer played a crucial role in analyzing the stability of the samples, providing data that enabled more precise results. The absorption peak at a wavelength of 294 nm reached its highest absorption value of 0.892 (a.u.) at a concentration of 0.2 g/L. In the case of MWCNT, after testing all samples, concentrations of 0.5, 0.55, and 0.65 g/L were identified as the best options based on peak absorption at different wavelengths, with their peaks at 4.87, 4.045, and 4.116 (a.u.), respectively. The Zeta Potential Analyzer confirmed the stability of these concentrations, indicating a moderate stability with values around -37.4 mV. This level of stability was also observed in MWCNT samples, with the three chosen concentrations showing excellent stability at 88.4, -84.9, and -137 mV, respectively. Among all tested nano-lubricant samples, those with concentrations of 0.2 g/L and 0.65 g/L for Graphene/CTAB/POE and MWCNT/POE, respectively, demonstrated the highest stability and optimum performance. This suggests that these concentrations have the potential to serve as replacements for POE oil in refrigeration systems.

Nanoarchitectonics with cetrimonium bromide on metal nanoparticles for linker-free detection of toxic metal ions and catalytic degradation of 4-nitrophenol.

Heavy metal ions and organic pollutants, such as 4-nitrophenol (4-NP), pose significant environmental and human health threats. Addressing these challenges necessitates using advanced nanoparticle-based systems capable of efficient detection and degradation. However, conventional approaches utilizing strong capping agents like cetrimonium bromide (CTAB) on nanoparticles lead to limitations due to the rigid nature of CTAB. This restricts its utility in heavy metal detection and 4-NP degradation, requiring additional surface modifications using linker molecules, thereby increasing process complexity and cost. To overcome these limitations, there is a critical need for the development of an easy-to-use, dual-functional, linker-free nanosystem capable of simultaneous detection of heavy metals and efficient degradation of 4-NP. For enabling linker-free/ligand-free detection of heavy metal ions and catalytic degradation of 4-NP, CTAB was engineered as a versatile capping agent on gold and silver nanoparticles. Various factors, including nanoparticle characteristics such as shape, size, metal composition, centrifugation, and NaOH amount, were investigated for their impact on the performance of CTAB-capped nanoparticles in heavy metal detection and 4-NP degradation. CTAB-Au nanospheres demonstrated limited heavy metal ion detection capability but exhibited remarkable efficiency in degrading 94.37% of 4-NP within 1 min. In contrast, silver nanospheres effectively detected Hg2+, Cu2+, and Fe3+ at concentrations as low as 1 ppm and degraded 90.78% of 4-NP within 30 min. Moreover, anisotropic gold nanorods (CTAB-AuNR1 and CTAB-AuNR2) showed promising sensing capabilities towards Cu2+, Cr3+, and Hg2+ at 0.5 OD, while efficiently degrading 4-NP within 5 min at 1 OD. This study emphasizes the importance of tailoring parameters of CTAB-capped nanoparticles for specific sensing and catalytic applications, offering potential solutions for environmental remediation and human health protection.

Adsorptive removal of carcinogenic azo dye from aqueous solution using NaCPT@HDTMA

ABSTRACT This study investigated the effectiveness of the clinoptilolite (Na@CPT) surface as an adsorbent for removing anionic dyes. The Na@CPT surface was modified using hexadecyltrimethylammonium bromide (NaCPT@HDTMA) to improve its ability to remove Reactive Blue 171 (RB171) from water. A thorough study was conducted to analyze the adsorption isotherms, kinetics, temperature, and pH effects of RB171 onto Na@CPT and NaCPT@HDTMA. A pH of 1.0 was found to be the optimum value for adsorbents. Kinetic studies revealed that both adsorbents followed the pseudo-second-order kinetic model, with NaCPT@HDTMA exhibiting a faster adsorption process and quickly reaching equilibrium with increasing temperature. The adsorption efficiency of RB171 was found to improve by 83.56% after the modification at 50°C. The equilibrium data showed that the adsorption of RB171 on Na@CPT and NaCPT@HDTMA fit the Freundlich and Langmuir isotherm models, respectively. The thermodynamic parameters showed that the overall adsorption process of both adsorbents was endothermic and spontaneous. NaCPT@HDTMA is a highly effective adsorbent for removing RB171 from aqueous solution due to its low cost and abundant presence in nature.

Efficient RhB degradation and antimicrobial activity with molecular docking study of polymers doped ZnSe nanostructure

A facile coprecipitation approach was adopted to synthesize zinc selenide (ZnSe) doped with a fixed amount (3 wt%) of cetyltrimethylammonium bromide (CTAB) and different concentrations (2 and 4 wt%) of eudragit to form ternary nanostructure (NSs). Eud and CTAB inhibit the dimension and reduce the rate of recombination of NSs to intensify catalytic performance against rhodamine B (RhB) and bactericidal action against MDR Staphylococcus aureus (S. aureus). Doped ZnSe increase active sites, porosity, and surface area to enhance the degradation of RhB dye and antimicrobial efficacy to kill pathogenic S. aureus. Assessment of 4 wt% Eud/CTAB exhibited effective performance for degradation of RhB and bactericidal potential highlights an impressive 94.3 % degradation efficiency and 8.85 ± 0.05 mm of the inhibition zone against MDR S. aureus. Computational molecular docking studies suggest that NSs, such as Eud/CTAB-doped ZnSe, have the ability to inhibit the DNA gyrase enzyme in MDR S. aureus.

Surfactant-modified zein nanoparticles adsorbents for ultrafast and efficient removal of Cr(VI)

The adsorption and removal of heavy metal ions Cr(VI) is of great significance for human health and ecological environment. Here, an ultrafast and high efficient adsorbent for Cr(VI) was developed based on cetyltrimethylammonium bromide (CTAB)-modified zein nanoparticles (C-ZNPs). In comparison to pristine zein nanoparticles (ZNPs) (11.199 m2 g−1), the surfactant-modified C-ZNPs exhibited larger specific surface area (17.002 m2 g−1). Moreover, C-ZNPs had superior dispersion and more positive charge distribution, which contributed to the improvement for adsorption performance. The results showed that the saturated adsorption of Cr(VI) was reached up to 192.27 mg/g using the C-ZNPs nanosorbent at T = 298 K, pH = 4, t = 10s, and C0 = 125 mg/L. The removal rate was significantly faster than that reported natural polymer-based adsorbents. The experimental values were followed Freundich isothermal model and pseudo-second-order kinetic model, indicating that the adsorption occurred primarily through a multimolecular layer adsorption process, with a strong emphasis on chemisorption. Mechanistic investigations further revealed that the adsorption of Cr(VI) onto C-ZNPs was mediated by various interactions, including electrostatic attraction, complexation, and ion exchange. These findings provide insights into the efficient removal of Cr(VI) by C-ZNPs and suggest potential applications in water treatment and environmental remediation.

Efficient removal of perfluorooctanoic acid from aqueous matrices using cationic surfactant functionalized graphene oxide nanocomposite: RSM and ANN modeling, and adsorption behaviour

Perfluorooctanoic acid (PFOA), a persistent and recalcitrant emerging organic contaminant, has garnered worldwide attention due to its pervasiveness and strong bioaccumulation, emphasizing the urgent necessity for effective removal strategies. To address PFOA contamination in the global aquatic environment, this study prepared cetyltrimethylammonium bromide (CTAB)-functionalized graphene oxide (GO-C) nanocomposites. The functionality of GO-C is controlled by varying loading ratios of CTAB to achieve satisfactory performance. After preliminary experiments that confirmed the superior performance of GO-C0.5 in PFOA removal, the response surface methodology (RSM) revealed the effects of different process parameters, which followed the sequence: adsorbent dose > pH > time. The optimum PFOA removal of 98.5 % was achieved at adsorbent dose: 200 mg/L, pH: 3.5, and time: 50 min, at an experimental temperature of 298 K. Furthermore, a predictive model using an artificial neural network was developed for PFOA adsorption, which closely aligns with the experimental data (R2: 0.9999). The PFOA adsorption was most accurately represented by Freundlich isotherm (R2: 0.9747) and pseudo-second-order kinetics (R2: 0.9995), with a maximum experimental adsorption capacity of ~709.94 mg/g under RSM optimized conditions. The adsorption mechanism involves electrostatic and hydrophobic interactions and hydrogen bonding, as confirmed by the spectroscopic and zeta potential analyses. Lastly, the competitive adsorption and regeneration experiments underscore the potential of GO-C nanocomposite in removing PFOA. Overall, this study provides insights into the development and application of sustainable and promising adsorbent for the removal of PFOA in wastewater stream.

Nano-sized MIL-101(Cr) MOF for CO2 separation: Crystal downsizing effects on adsorption and mixed matrix membranes

In this paper, nano-sized MIL-101(Cr) metal–organic framework (MOF) and the micro-sized one were synthesized. To reduce the average crystal size, a surfactant namely cetyltrimethylammonium bromide (CTAB) in its optimum amount (Cr3+:CTAB = 1:0.3) along with microwave heating (600 W, 30 min) were applied. The prepared MOFs were characterized by FESEM, EDS, PXRD, BET, FTIR, and TGA analyses. Moreover, CO2 and CH4 adsorption isotherms and kinetics were investigated at 298 K and equilibrium pressures up to 1 bar. The results revealed that the CO2/CH4 ideal adsorption selectivity was improved by 27.15 % for the downsized MOF, so-called MIL-101(Cr)/CTAB, compared to the micro-sized one. Furthermore, by incorporation of the MOFs into the Ultem® 1000 polymer, mixed matrix membranes (MMMs) were fabricated. The morphological analysis of the prepared membranes displayed proper dispersion and compatibility between the polymer and MOFs. The best separation performance was obtained for the MMM containing 20 wt% of the mesoporous MIL-101(Cr)/CTAB. For this MMM, the CO2 permeability and CO2/CH4 ideal perm-selectivity values were enhanced by ∼ 136 % and ∼ 18 %, respectively at 298 K and 4 bar, compared to the neat membrane.

Surface engineering of Fe3O4@SiO2 Core–Shell nanoparticles: Role of CTAB/TEOS ratio

Core– shell Fe3O4@SiO2 nanoparticles with tunable SiO2 shell thickness and porosity were successfully synthesized using cetyltrimethylammonium bromide (CTAB) as the crosslinking agent and tetraethyl orthosilicate (TEOS) as the silica precursor. The increase in the O-H stretching peak intensity observed in the Fe3O4/CTAB and Fe3O4/CTAB/SiO2 nanoparticles was attributable to the increased number of hydroxyl groups resulting from hydrogen bonding between the head of CTAB and water molecules and the increased exposure of the SiO2 surface owing to CTAB dissolution. The shell thickness and porosity of the nanoparticles were controlled by adjusting the TEOS/CTAB ratio. Increasing the CTAB content while maintaining a fixed amount of TEOS resulted in a constant shell thickness but increased porosity. Conversely, increasing the TEOS content while fixing the amount of CTAB led to the formation of a double-shell structure with a new dense silica layer on top of the existing shell at concentrations exceeding a certain threshold. These findings provide valuable insights into the design and application of SiO2-coated nanoparticles tailored for various applications.