Cetyltrimethylammonium Bromide Research Articles

A novel portable microchip electrophoresis system for rapid on-site detection of soil nutrient ions

Abstract The conventional techniques for soil nutrient ion detection face challenges, including prolonged preparation periods and the necessity for distinct instruments tailored to each specific ion. To address these issues, we have engineered a cutting-edge soil nutrient ion detection apparatus: the Microchip Electrophoresis Soil Nutrient Ion Portable Detection System (ME-SNI-PDS). This system, leveraging microchip electrophoresis with a capacitively coupled contactless conductivity detector (ME-C4D), simplifies the detection process with user-friendly touchscreen controls. Our system is capable of simultaneous detection of key soil nutrient ions—ammonium (NH4 +), calcium (Ca2+), magnesium (Mg2+), potassium (K+), nitrate (NO3 −), and dihydrogen phosphate (H2PO4 −)—in a swift 180 s, facilitated by precise voltage regulation. We have refined the buffer solution, consisting of 20 mM 2-(N-morpholinyl)-ethanesulfonic acid and L-histidine, with the addition of 0.01 mM cetyltrimethylammonium bromide and 10 mM 18-crown-6, to ensure the complete resolution of soil nutrient ions. Following this, we established highly accurate peak height-to-concentration correlations for the six aforementioned ions, each with a coefficient of determination (R2) exceeding 0.99. The detection limits for these ions stand at a remarkably low concentration of 0.05 mM, translating to 0.9 mg l−1 for NH4 +, 2.0 mg l−1 for Ca2+, 1.2 mg l−1 for Mg2+, 1.96 mg l−1 for K+, 3.1 mg l−1 for NO3 −, and 4.85 mg l−1 for H2PO4 −. Subsequent soil leachate analysis via the ME-SNI-PDS has yielded ion content data that, upon comparison with results from continuous flow analyser (CFA) and inductively coupled plasma atomic emission spectrometry, confirm the system’s exceptional integration, compactness, portability, speed, and efficiency. The ME-SNI-PDS shows immense promise for application in precision agriculture and the prevention of surface soil pollution. It is poised to make a significant impact in the realm of crop fertilization and environmental stewardship.

Efficient Poly-Adenine-Tailed DNA Functionalization of Gold Nanorods for Tailored Nanostructure Assembly.

Gold nanorods (AuNRs) with unique optical properties play a pivotal role in applications in plasmonic imaging, small molecule detection, and photothermal therapy. However, challenges in DNA functionalization of AuNRs hinder their full potential due to the presence of a dense cetyltrimethylammonium bromide (CTAB) bilayer, impeding close DNA contact. In this study, we introduced a convenient approach for the rapid assembly of polyadenine (polyA) tailed DNA on AuNRs with control of DNA density, rigidity, and valence. We explored the impact of DNA with designed properties on the construction of core-satellite structures by employing AuNRs as cores and spherical gold nanoparticles (AuNSs) as satellites. Density, rigidity, and valence are identified as crucial factors for efficient construction. Specifically, polyA-tailed DNA modulated DNA density and reduced spatial hindrance and electrostatic repulsion, thereby facilitating the construction. Enhancing the rigidity of DNA and incorporating multiple binding sites can further improve the efficiency.

Critical Assessment of Micellar Surface Charge-Dependent Disaggregation and Reaggregation of a Bis-Indole Self-Aggregate: What Should Be Our Case-Dependent Choice?

"Aggregation-caused quenching" is a deep-seated mechanism and has been widely used by the researchers as the possible basis for new sensor development. Contrast to aggregation, its turn around process, disaggregation, has gained much less consideration so far. Unfortunately, study of the further scope for reaggregation of the disaggregated probe assembly in the same solution, as and when required, is still under the rare category. The central theme of the current study is focused on this aspect. For this purpose, the effects of headgroup charge (cationic, anionic, and nonionic) and polarity of the micelles on the degree of disaggregation and subsequent emission amelioration of a synthesized bis-indole derivative, 3,3'-bisindolyl(phenyl)methane (BIPM), are studied using steady-state and time-resolved spectroscopic techniques. The relative emission yield of BIPM (φf = 0.01) is significantly enhanced in the presence of cetyltrimethylammonium bromide (φf = 0.21) and polyoxyethylene (20) sorbitan monolaurate (φf = 0.24), whereas comparatively less emission enhancement is recorded within the sodium dodecyl sulfate system (φf = 0.07). In contrast, addition of an external biophilic agent, uric acid, causes requenching of the enhanced emission because of the reaggregation of the disaggregated probes. Detailed microscopic and calorimetric studies are also adopted to investigate the disaggregation-reaggregation mechanism of BIPM associations. The study will provide prior insights about the use of suitable micellar systems for the required degree of disaggregation as well as for the modulation of emission efficiency by controlled tuning of the disaggregation-reaggregation equilibrium for similar probe associations in pure aqueous medium avoiding any chemical transformation.

Cetyltrimethylammonium Bromide-Modified Laponite@Diatomite Composites for Enhanced Adsorption Performance of Organic Pollutants.

This work aims to enhance the adsorption performance of Laponite @diatomite for organic pollutants by modifying it with cetyltrimethylammonium bromide (CTAB). The microstructure and morphology of the CTAB-modified Laponite @diatomite material were characterized using SEM, XRD, FTIR, BET, and TG. Furthermore, the influences of key parameters, containing pH, adsorbent dosage, reaction time, and reaction temperature, on the adsorption process were investigated. The kinetics, thermodynamics, and isotherm models of the adsorption process were analyzed. Finally, potential adsorption mechanisms were given based on the characterization. The research findings indicate that CTAB-La@D exhibits good adsorption performance toward Congo red (CR) over a broad pH range. The maximum adsorption capacity of CR was 451.1 mg/g under the optimum conditions (dosage = 10 mg, contact time = 240 min, initial CR concentration = 100 mg/L, temperature = 25 °C, and pH = 7). The adsorption process conformed to the pseudo-second-order kinetic model, and the adsorption isotherms indicated that the adsorption process of CR was more in line with the Langmuir model, and it was physical adsorption. Thermodynamic analysis illustrates that the adsorption process is exothermic and spontaneous. Additionally, the mechanisms of electrostatic adsorption and hydrophobic effect adsorption of CR were investigated through XPS and FTIR analysis. This work provides an effective pathway for designing high-performance adsorbents for the removal of organic dye, and the synthesized materials hold great capability for practical utilization in the treatment of wastewater.

Synthesis and Study of Superhigh-Concentrated Organosols of Silver Nanoparticles

Abstract Due to their unique properties, organosols of silver nanoparticles are widely used in optical and semiconductor devices, to produce electrically and thermally conductive films, as catalysts, antibacterial materials, etc. This work proposes a simple and highly productive method for the preparation of silver organosols, which have a metal concentration as high as 1800 g/L and contain spherical nanoparticles with low polydispersity and a median size of 9.1 nm. The method consists in the initial preparation of silver nanoparticle hydrosols with a concentration of higher than 30 g/L followed by the transfer of the NPs into an organic phase of o-xylene. A set of physical research methods has been employed to study the regularities of the extraction of silver nanoparticles with o-xylene in the presence of cetyltrimethylammonium bromide (CTAB) and ethanol and to determine the optimal process conditions, under which the extraction degree is as high as 62.5%. It has been found that bromine anions contained in CTAB molecules cause the aggregation of some amount of silver nanoparticles with the formation of silver metal sediment in the aqueous phase. According to X-ray photoelectron spectroscopy data, the sediment contains bromide ions (up to 4 at %) on the particle surface. Organosols synthesized under optimal conditions are stable for more than 7 months and withstand repeated cycles of drying and redispersing. Silver organosols have been used to obtain metal films with an electrical conductivity of about 68 500 S/cm, which increases to 412 000 and 509 500 S/cm (87.8% of the electrical conductivity of bulk silver) after thermal treatment at 150 and 250°C, respectively.

Potentiometric Surfactant Sensor with a Pt-Doped Acid-Activated Multi-Walled Carbon Nanotube-Based Ionophore Nanocomposite

Two new surfactant sensors were developed by synthesizing Pt-doped acid-activated multi-walled carbon nanotubes (Pt@MWCNTs). Two different ionophores using Pt@MWCNTs, a new plasticizer, and (a) cationic surfactant 1,3-dihexadecyl-1H-benzo[d]imidazol-3-ium-DHBI (Pt@MWCNT-DHBI ionophore) and (b) anionic surfactant dodecylbenzenesulfonate-DBS (Pt@MWCNT-DBS ionophore) composites were successfully synthesized and characterized. Both surfactant sensors showed a response to anionic surfactants (dodecylsulfate (SDS) and DBS) and cationic surfactants (cetylpyridinium chloride (CPC) and hexadecyltrimethylammonium bromide (CTAB)). The Pt@MWCNT-DBS sensor showed lower sensitivity than expected with the sub-Nernstian response of ≈23 mV/decade of activity for CPC and CTAB and ≈33 mV/decade of activity for SDS and DBS. The Pt@MWCNT-DHBI surfactant sensor had superior response properties, including a Nernstian response to SDS (59.1 mV/decade) and a near-Nernstian response to DBS (57.5 mV/decade), with linear response regions for both anionic surfactants down to ≈2 × 10−6 M. The Pt@MWCNT-DHBI was also useful in critical micellar concentration (CMC) detection. Common anions showed very low interferences with the sensor. The sensor was successfully employed for the potentiometric titration of a technical grade cationic surfactant with good recoveries. The content of cationic surfactants was measured in six samples of complex commercial detergents. The Pt@MWCNT-DHBI surfactant sensor showed good agreement with the ISE surfactant sensor and classical two-phase titration and could be used as an analytical tool in quality control.

High Quality and Purified DNA Extraction Protocol from Transplastomic Potato Lines by Cetyltrimethylammonium Bromide (CTAB)-Based Method

For the advanced molecular techniques high quality and pure DNA is important requirement where a quick and cost-effective extraction method is a crucial factor. Commonly, prolong incubation period, multiple precipitations, and highly expensive commercial kits are remaining basic barrier to introduce swift and easiest method of DNA extraction from transgenic plants. Non-cellulose components present in the leaf and elevated level of starch content as well as protein content also makes this extraction procedure challenging and difficult. Present study was conducted to establish a unique DNA isolation method with some modification of existing CTAB method to ensure high-quality and purified genomic DNA from the potato plants. Through the implementation of solution based and selective DNA precipitation method, 100 mg of potato leaves from every transplastomic potato lines was applied to extract genomic DNA. Ethanol (70%) was used as elution buffer where maximum DNA yield was 3415.500 ng/µl and the ranges of DNA purity (A260/A280 nm) was recorded as 1.954-2.048, respectively. Compared to existing methods, this modified CTAB mediated procedure is swift (at least one hour can be saved ) and proficient enough for high quality DNA yield, free from the selective precipitation, regents and laboratory equipment’s are cost-effective and non-toxic to human health.

Insights into the Ligand Effect in β-CD@Fe3O4 Composites to Activate Peroxymonosulfate for Efficient Degradation of Pharmaceutical Contaminants: A Study Employing Density Functional Theory

This study presents a detailed investigation into the use of β-cyclodextrin (β-CD) encapsulated iron oxide nanoparticle (β-CD@Fe3O4) composites, modified with different ligands, to activate peroxymonosulfate (PMS) for the degradation of pharmaceutical contaminants, namely, diclofenac, carbamazepine, and erythromycin. The focus is on understanding the ligand effect, particularly using citric acid (CIT), polyethyleneimine (PEI), and cetyl trimethyl ammonium bromide (CTAB), on the degradation performance of these composites. Employing density functional theory (DFT) calculations, this work examines the electronic structure and charge distributions of β-CD@Fe3O4 composites, providing insights into their interaction with various pollutants. The study reveals that the β-CD@PEI@Fe3O4 composite demonstrates superior degradation efficiency due to optimal electrostatic interactions, regardless of the pollutant’s hydrophobicity. On the other hand, β-CD@CIT@Fe3O4 shows moderate efficiency, and β-CD@CTAB@Fe3O4 exhibits selective efficiency, particularly for hydrophobic compounds. These findings underscore the significant role of surface chemistry in modulating the activation of PMS and the degradation of contaminants, opening avenues for designing tailored β-CD composites for environmental remediation.

Chiral Biocatalytic Oxidations at 90 °C in Microemulsions Driven by Electrocatalytic Oxygen Reduction to Hydrogen Peroxide

AbstractChirality plays a significant role in the manufacture of pharmaceuticals and fine chemicals. The use of chemical catalysts to control stereoselectivity relies on the use of chiral catalysts with labor–intensive synthesis and purification. Natural enzymes offer inherent stereoselectivity, making them attractive catalysts for this purpose. We report here chiral biocatalytic oxidations in microemulsions driven by horseradish peroxidase coupled with a synthetic Cu2+‐polymer catalyst. This hybrid system features crosslinked layer–by–layer (LBL) films composed of polyions with Cu2+‐containing pyrene–labelled poly(2‐hydroxy‐3‐dipicolylamino) propyl methacrylate (Py−PGMADPA) to drive oxygen reduction to form hydrogen peroxide. Peroxide in turn activates horseradish peroxidase (HRP) crosslinked in LbL films on magnetic particle beads to biocatalytically oxidize styrene, ethylbenzene, and methyl phenylacetate to chiral products. R‐stereoisomers of these reactants were selectively formed with a high enantiomeric excess of ≥80 % at 90 °C. The enzyme films show high thermal stability at 90 °C in cetyltrimethylammonium bromide microemulsion. Reactions at 90 °C were essentially complete in 2 hr. This hybrid approach opens a door to new designs of biocatalytic syntheses using a separate electrocatalyst for enzyme activation.

Online structural health monitoring of polymer composite structure using gold nanoparticles (AuNPs)

A mechanism for online structural health monitoring of composite structure was established by developing highly sensitive strain gauges based on colloidal Gold Nano Particles (AuNPs). They were synthesized using well known Turkevich-Frens method followed by phase transfer in chloroform using surfactant Cetyltrimethylammonium bromide (CTAB). Flexible Strain gauges / smart sensors were formed by mixing colloidal AuNPs-chloroform solution in polystyrene (PS) – chloroform solution and depositing their thick paste on hand-made flexible thermoplastic polyurethane (TPU) film. These sensors were used as strain gauges on composite substrates for tensile testing. The developed AuNP based strain gauges were found to have 10 times higher sensitivity than normal metal foil strain gauges.

Engineering Interconnected Open-Porous Particles via Microfluidics Using Bijel Droplets as Structural Templates.

Designing porous structures is key in materials science, particularly for separation, catalysis, and cell culture systems. Bicontinuous interfacially jammed emulsion gels represent a unique class of soft matter formed by kinetically arresting the separation of the spinodal decomposition phase, which is stabilized by colloidal particles with neutral wetting. This study introduces a microfluidic technique to create highly interconnected open-porous particles using bijel droplets stabilized with hexadecyltrimethylammonium bromide (CTAB)-modified silica particles. Monodisperse droplets comprising a hydrophobic monomer, water, ethanol, silica particles, and CTAB were initially formed in the microfluidic device. The diffusion of ethanol from these droplets into the continuous cyclohexane phase triggered spinodal decomposition within the droplets. The phase-separated structure within the droplets was stabilized by the CTAB-modified silica particles, and subsequent photopolymerization yielded microparticles with highly interconnected, open pores. Moreover, the influence of the ratio of the CTAB and silica particles, fluid composition, and microchannel direction on the final structure of the microparticles was explored. Our findings indicated that the phase-separated structure of the particles transitioned from oil-in-water to water-in-oil as the CTAB/silica ratio was increased. At intermediate CTAB/silica ratios, microparticles with bicontinuous structures were formed. Regardless of the fluid composition, the pore size of the particles increased with time after phase separation. However, this coarsening was arrested 15 s after droplet formation in the CTAB-modified silica particles, accompanied by a change in the particle shape from spherical to ellipsoidal. In situ observations of the bijel droplet formation revealed that the particle shape deformation is caused by the rolling of elastic bijel droplets at the bottom of the microchannel. As such, the channel setup was altered from horizontal to vertical to prevent the deformation of bijel droplets, resulting in spherical particles with open pores.

Seed-Mediated Electrodeposition of Silver Nanowires and Nanorods.

Here, we compare the amount and morphology of silver (Ag) nanostructures electrodeposited at varied potentials and times in the presence of cetyltrimethylammonium bromide (CTAB) onto glass/indium tin oxide (glass/ITO) electrodes functionalized with mercaptopropyltrimethoxysilane (MPTMS) and coated or not coated with 4 nm average diameter Au nanoparticle (Au NP) seeds. There is a significantly larger amount of Ag deposited on the seeded electrode surface compared to that in the nonseeded electrode at potentials of -150 to -300 mV (vs Ag/AgCl) since the Au NP seeds act as catalysts for Ag deposition. At more negative overpotentials of -400 to -500 mV, the amount of Ag deposited on both electrodes is similar because the deposition kinetics are fast enough on glass/ITO that the Au seed catalyst does not make as big of a difference. Ag nanorods (NRs) and nanowires (NWs) form on the seeded surfaces, especially at more positive potentials, where deposition primarily occurs on the Au seed catalysts. Deposition of Ag onto the Au seeds appears as a separate peak in the voltammetry. This procedure mimics the seed-mediated growth of Ag NRs observed in solution in the presence of CTAB using ascorbic acid as a reducing agent. The yield, length, and aspect ratio of the Ag NRs/NWs depend on the deposition time and potential with the average length ranging from 300 nm to 3 μm for times of 30-120 min and potentials of -150 to -200 mV. The electrochemical seed-mediated growth of Ag NRs/NWs across electrode gaps could find use for resistive and surface-enhanced Raman-based sensing and molecular electronic applications.

Synthesis and characterization of MOF polymer nanocomposites for Chromium adsorption and their antimicrobial properties

This study describes the preparation of MOF and its polymer composites, namely Co@BTC(MOF1), Co@BTC(PAA)(MOF2), and Co@BTC(PAA)(CTAB)(MOF3), by assimilating cobalt nitrate hexahydrate [(CoNO3)2·6H2O] with trimesic acid, polyacrylic acid (PAA), and cetyltrimethylammonium bromide (CTAB) using a solvothermal procedure at 100℃ for 12 h. All MOF composites exhibited remarkable adsorption properties and thermal and chemical stability properties. These polymer composite MOFs are explored for the adsorption of anionic dyes such as Methyl Orange (MO) and Congo Red (CR), cationic dye Methylene Blue (MB), and Chromium (VI) from wastewater. A 90–95 % adsorption rate for MO and CR dyes was observed within 60 min using 100 mg of MOF composites. Within 60 min, the MOF composites achieved an adsorption rate of 90–95 % for MO and CR dyes when 100 mg of the composites were used. Furthermore, MOF2 and MOF3 have exhibited a remarkable 92 % efficiency in adsorbing Cr(VI) during one hour, following a pseudo-second-order kinetic model. The composites were examined for their anti-bacterial efficacy against Bacillus (Gram-positive), E. Coli (Gram-negative), and Saccharomyces cerevisiae. The results were compared to ciprofloxacin, a conventional antibiotic, using the agar diffusion method. MOF2 and MOF3 have demonstrated long-lasting and potent antimicrobial activity, successfully inhibiting the growth of bacteria for a period of at least 90 days. Furthermore, the polymer composites of MOFs exhibit notable capability in scavenging radicals, particularly against ascorbic acid, as determined by the DPPH method. The inhibition rates for the composites are 68.7 % and 65.9 %, respectively. This indicates that these polymer MOF composites possess potent anti-microbial activity, making them an ideal candidate for addressing the inhibition of bacterial growth.

Controlled release of foam from mesoporous silica-surfactant nanocomposite for enhanced natural gas production

Foam generated from solid foam sticks plays a crucial role in enhancing natural gas production by mitigating liquid accumulation in gas wells. Traditional solid foam sticks dissolve rapidly, releasing foam instantly, particularly at high downhole temperatures in gas wells. This necessitates frequent addition of surfactants to sustain foam generation. To address this issue, this study investigates the use of mesoporous silica nanocomposite to encapsulate the surfactant, cetyltrimethylammonium bromide (CTAB), as foam sticks, allowing for extended foam release. Mesoporous silica was synthesized through a sol–gel process involving a silica precursor and surfactant, utilizing alkali-acid catalysts in two steps. The resulting nanocomposite solid sticks were formed through aging and drying in a mold. The silica-surfactant nanocomposite was characterized by infrared spectroscopy (IR), scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), and small angle X-ray diffraction (SAXD). Experimental results demonstrated the successful encapsulation of 68.2 % surfactant into an average size of 50 nm nanosized silica capsules with a mesoporous structure. Quantitative determination of surfactant release over time in brine at a high temperature (130 °C) was determined through thermogravimetric analysis (TGA), which showed 6.3 % surfactant remained in nanocomposite after 3 days. Foam performance from the released surfactants was evaluated using a dynamic foam apparatus and blender test. The study showed that foam could be control-released over a period of 7 days through surfactant diffusion from mesoporous nanoparticles. The release of CTAB follows the first-order release kinetic model. This research provides a sustainable solution by utilizing mesoporous silica nanoparticles as carriers for surfactants, resulting in longer-lasting foam for the gas well deliquification and the enhancement of gas production.

Influence of pH on spectroscopic and interfacial features of phenol in aqueous cetrimonium bromide solutions of different concentrations

Phenol is an aromatic compound with toxic effects on the environment and living organisms. Cetrimonium bromide (CTAB) is a cationic, quaternary ammonium surfactant, constituent in industrial formulations, and is employed for solubilization as well as removal of pollutants. This study explores the impact of pH on the behavior of phenol in the micellar solution of CTAB via UV–Visible spectroscopy and surface tension measurements at room temperature. Binding coefficient (Kb), free energy change of binding (ΔGb), change in molar absorptivity (Δε), partition coefficient (Kc), free energy change of partitioning (ΔGp) and number of molecules per micelle (n) were determined at different pH. Results showed that phenol exhibits no appreciable interaction with the CTAB, however phenolate ions have the tendency to bind with CTAB micelles and penetrate in the palisade layer of CTAB.Surface properties such as surface excess (τmax), minimum area per molecule (Amin), packing parameter (P), surface area per head group (as), free energy changes of micellization (ΔGm), adsorption ΔGads, and transfer (ΔGtrans), and surface pressure (Π) for CTAB, and phenol in CTAB solutions were also determined. Interfacial studies supported the role of phenol in facilitating micellization of CTAB thermodynamically and hence a fall in CMC values of CTAB except for pH 7.11. Calculated interfacial parameters established the influence of phenol over rearrangement and surface adsorption of CTAB molecular ions at air/water interface. Surface tension results also showed that unionized phenol molecules have low surface activity (62.23mN/m), but when phenol is ionized into phenolate ion surface dramatically increased (44.17 mN/m).

Solvent selective gelation of cetyltrimethylammonium bromide: structure, phase evolution and thermal characteristics.

We report herein the gelation behaviour of cetyltrimethylammonium bromide (CTAB), a cationic surfactant, in a variety of solvent compositions. A turbid gel of CTAB in a binary solvent mixture at a critical composition was observed to be 1 : 3 v/v toluene : water. The molecular structure of the as-formed gel was investigated by X-ray diffraction and microscopic techniques, namely, optical and polarizing microscopy, scanning electron microscopy and small-angle X-ray scattering (SAXS). The phase evolution has been studied using UV-visible transmittance measurements and the thermal characteristics of the gel by differential scanning calorimetry measurements. SAXS studies, in conjunction with molecular modelling, revealed the gel to assemble as lamellae with high interdigitation of bilayer assembly of CTAB molecules with predominant non-covalent interactions, where the gel lamellae were inferred from the interplanar spacings. Rheological studies revealed the viscoelastic nature of the CTAB gels. The ability to form a gel has been evaluated in several polar solvents, such as methanol and chloroform, and non-polar solvents, such as toluene and carbon tetrachloride.

Adsorption of anionic dyes from aqueous solutions by a novel CTAB/MXene/carbon nanotube composite: Characterization, experiments, and theoretical analysis

A novel three-dimensional composite was prepared by the self-assembly of MXene nanosheets and carbon nanotubes (CNTs) with the assistance of cetyltrimethylammonium bromide (CTAB), which was named as CMC composite. Adsorption of three anionic dyes, including Acid orange (AO7), Methyl orange (MO) and Congo red (CR), from aqueous solutions on the composite and the mechanisms were investigated in this study. Compared with MXene and CNTs, the CMC composite exhibited superior adsorption performance for AO7, MO and CR with maximum adsorption capacities of 367.9, 294.2, and 628.5 mg/g, respectively. The adsorption capacities of AO7 and MO on the CMC composite decreased, while that of CR increased with increasing temperatures. Quantum chemical calculations indicated that electrostatic interactions, π-π electron-donor-acceptor interactions and hydrogen bonding played important roles on the adsorption. The approximate site energy distribution analysis demonstrated that more adsorption active sites existed on the CMC composite than on MXene and CNTs, which endowed the CMC composite with higher adsorption capacities for these anionic dyes. The differences of adsorption behaviors for three anionic dyes could be ascribed to the number of available adsorption sites and the change of the site heterogeneity on the CMC surface.

Regression analysis on the stability of surfactant mixed-MoO3 nanoparticles dispersed Gossypium arboretum biodiesel

ABSTRACT The stability, physicochemical characteristics, molybdenum trioxide (MoO3) nanoparticles in Gossypium arboretum biodiesel (BD20), and deduction of the regression equation for parameters governing the stability of biodiesel are the main subjects of this study. With and without the surfactant Cetyltrimethylammonium Bromide (CTAB), MoO3 nano additions were combined with BD20 at 60, 80, and 100 ppm concentrations. A spectrophotometer that measures the samples’ absorbance and transmittance was used to examine the stability of nano fuels on days 1, 10, and 20. CTAB mixed nano samples demonstrated high stability and enhanced essential fuel qualities when compared to basic nano fuels. The fuel BD20MoO380CTAB80 (BD20+ MoO3 80 ppm+ CTAB 80 ppm) showed a decreased transmittance of 88.3% and a higher absorbance of 4.3 AU.BD20MoO380CTAB80 recorded a higher value of Cetane number of 64 and a heating value of 41,238 kJ/kg. Physicochemical properties such as Kinematic Viscosity and Relative Density recorded lower values of 4.23 cSt and 880 kg/m3. Linear regression is applied to the obtained absorbance and transmittance values.

Synergistic Humidification and Chemical Agglomeration to Improve Capturing the Fine Particulate Matter by Electrostatic Precipitator

The wet electrostatic precipitator (WESP) overcomes the shortcomings of traditional electrostatic precipitators, such as dust re-entrainment and back corona. It can effectively remove high-specific-resistivity dust, with a good removal effect on PM2.5. It is proposed to adopt chemical agglomeration and humidification agglomeration technology in the wet electrostatic precipitators to achieve ultra-low dust emissions from coal-fired power plants. The results show that the addition of chemical agglomerates, surfactants, and water vapor all affect the dust diameter of coal-fired power plants. After adding sesbania gum (SG), the D50 of dust particles increases from 28.29 μm to 48.22 μm. And the D50 of dust particles is 36.46 μm when spraying 3.6 kg/h water vapor only. With the cooperation of chemical agglomeration agents and water vapor, the dust agglomeration effect and removal efficiency can be further improved. When 10 mg/L SG is synergistically combined with 2.9 kg/h water vapor, the D50 is 64.75 μm, and the dust removal efficiency reaches 97.88%. On this basis, by adding 5 mg/L of Hexadecyltrimethylammonium bromide (CTAB), the D50 is 83.06 μm, and the dust removal efficiency increases to 98.62%. The synergistic effect of chemical agglomeration and humidification agglomeration promotes the aggregation of dust from coal-fired power plants. It can improve the removal efficiency of WESP for fine particulate matter but has little impact on the operation of existing equipment. The synergistic effects of multiple agglomeration technologies are also the direction for future research on the removal efficiency of fine particulate matter.

In English

Samples of MnOx-Na2WO4/SiO2 based on a mesoporous silica matrix were synthesized using manganese acetate, sodium tungstate, tetraethoxysilane (TEOS) as precursors and cetyltrimethylammonium bromide (CTAB), citric acid and triethanolamine as pore generating agent and characterized by scanning electron microscopy with energy dispersive elemental analysis (SEM/EDS), X-ray diffractometry (XRD), electron magnetic resonance (EMR), N2 adsorption-desorption measurements and tested as a catalyst for the reaction of oxidative condensation of methane (OCM). It is shown that the MnNaW/SiO2 catalyst consists of Mn2O3, MnO2, Na2WO4 and SiO2 phases. The EMR and SEM/EDS data indicate a noticeable effect of the reaction conditions on the surface structure and the distribution of catalytically active components in the catalyst structure. Significant changes in the values of the specific surface area and pore volume of the samples with increasing temperature and duration of the reaction were found (the values of the specific surface area and pore volume, respectively, 116.8 m2/g and 0.590 cm3/g - up to and 46.1 m2/g and 0.232 cm3/g after 15 hours of catalyst operation in the OCM reaction at 800 °C). It has been shown that under the conditions of the OCM reaction, the elemental composition of the surface of the MnOx-Na2WO4/SiO2 catalyst changes, and the degree of change depends on the duration of the OCM reaction. Under the influence of the reaction mixture CH4/O2, the content of Mn and W decreases in the first two hours, and the trend towards a decrease in their amount on the catalyst surface with an increase in the duration of the OCM reaction is generally preserved. A detailed X-ray phase analysis also indicates a change in the phase composition of this catalyst under the influence of the CH4/O2 reaction mixture. It is assumed that under the reaction conditions (700–800 °C) the MnOx-Na2WO4/SiO2 catalyst is silicon dioxide particles basely with the cristabolite structure, the surface of which is coated with molten sodium tungstate containing nanosized particles of MnOx structures activated by sodium ions and WOx.