Surfactant Hexadecyltrimethylammonium Bromide Research Articles

Carbamazepine adsorption with a series of organoclays: removal and toxicity analyses

Organoclays have been used as efficient adsorbents for pharmaceutical pollutants present in waters. Carbamazepine (CBZ) is one of the drugs most frequently found in water bodies. In this study, four organoclays were prepared by modifying bentonite with the cationic surfactants hexadecyltrimethylammonium bromide (HDTMA) and octadecyltrimethylammonium bromide. The synthesized materials were characterized by XRD, CHN, FTIR, TG, BET and SEM analyses, confirming organophilization. The surfactants were interspersed in different arrangements in the interlayer space. CBZ sorption was investigated through batch equilibrium experiments, under variation of the pH, contact time, dosage of adsorbent, and initial drug concentration. Changes in pH showed no adsorption influence. CBZ sorption by the organoclays followed a pseudo-second-order kinetics. The best sorption performance was obtained for the BCN1-HDTMA100 clay, with a capacity of 34.34 ± 1.41 mg g−1, about ten times greater than the unmodified bentonite under the same conditions. This may be attributed to the higher surfactant content. The adsorption isotherm at 25 ºC showed linear behavior. Toxicity tests of the organoclays and corresponding medium in presence of CBZ were carried out. This is a novelty report. Most of the organoclays had no toxicity against Artemia salina. The toxicity of the medium after adsorptive treatment was eliminated. Organoclay-CBZ hybrids were also characterized after adsorption. FTIR and TG analyzes confirmed the incorporation of the drug. Hydrophobic interaction was the dominant contribution evaluated to the adsorption of CBZ. The results demonstrated that organoclays can be a promising alternative adsorbent for the removal of pharmaceutical pollutants in water remediation.

Surface-active agent enhanced FRET effect Cu-doped NH2-MIL-88(Fe) for highly sensitive detection of 3-nitro-L-tyrosine

In this study, Cu-doped NH2-MIL-88(Fe) metal–organic frameworks (MOF) were synthesized via a one-step method. Characterization techniques such as XPS, XRD and FTIR confirmed the successful incorporation of Cu2+ into NH2-MIL-88(Fe), naming this MOF as NH2-MIL-88(Fe)@Cu2+. This MOF was employed to develop a highly sensitive fluorescence sensing platform for detecting 3-nitro-L-tyrosine(3-NT). The potential for fluorescence resonance energy transfer (FRET) was suggested by the spectral overlap between NH2-MIL-88(Fe)@Cu2+'s emission and 3-NT's UV absorption. To augment this effect, cationic surfactant hexadecyltrimethylammonium bromide (CTAB), which self-assembled into nanostructured microspheres above its critical micelle concentration, was utilized. The charged surface of these microspheres, formed by the self-assembly of CTAB, is bound to the MOF surface through electrostatic force and simultaneously attracts 3-NT. Adjusting the solution's pH strengthened the interaction between NH2-MIL-88(Fe)@Cu2+ and 3-NT, thereby enhancing their mutual FRET interaction. Experimental results indicated that CTAB's introduction markedly improved the FRET effects, potentially converting a weak FRET into a strong one and enhancing detection sensitivity and accuracy. Under optimal conditions, NH2-MIL-88(Fe)@Cu2+ detected 3-NT within 0–30 μM range, with a limit of detection (LOD, S/N = 3) of 41.1 nM. Finally, the applicability of the sensor is tested by calibrating measurements in fetal bovine serum samples, achieving good performance in terms of sensitivity, selectivity and reproducibility. This research provides a method for efficient and highly sensitive 3-NT detection and insights into the FRET effect between MOF and target molecules, likely advancing related fields and inspiring future fluorescence sensor designs.

Determination of Lead in Bee Products by Solid Surface Fluorescence Using Complexation and Coacervation at Room Temperature Processes. An Environmental Friendly Methodology.

An accurate, economic and green methodology for Pb(II) monitoring in bee products is proposed. Complexed metal traces were preconcentrated on Nylon membranes using the coacervation phenomenon based on room temperature reaction between the cationic surfactant hexadecyltrimethylammonium bromide and the bile salt sodium cholate. The increase in solid surface fluorescence signal of dyes 8-hydroxyquinoleine and o-phenanthroline due to Pb(II) presence was used for the metal quantification. Experimental variables that influence on preconcentration step and fluorimetric sensitivity were optimized using uni-varied assays. Pb(II) concentration was determined on membranes by solid surface fluorescence at λem = 470nm (λexc = 445nm), using a solid sample holder. The calibration at optimal experimental conditions showed a LOD of 4.2 × 10-4mg Kg-1 with a linear range of 1.28 × 10-3mg Kg-1 to 8.73mg Kg-1 and was successfully applied to Pb(II) quantification in different bee products produced in central west region of Argentina. The proposed methodology was applied to all samples after appropriate dilution. Accuracy methodology was evaluated by comparison of the obtained results with those found by ICP-MS, with percentage relative error under 8%. The precision was better than 0.0344 CV for Pb(II) determination.

Phenol degradation and Sb(V) adsorption by superparamagnetic CTAB-modified iron calcium composite

The heavy metal ions and organic dyes in textile wastewater treatment pose a significant environmental burden and are challenging to effectively manage. A magnetic cationic surfactant hexadecyltrimethylammonium bromide (CTAB), modified iron-calcium composite (referred to as CIC), was prepared using a straightforward method from iron-calcium composites as raw materials. The simultaneous catalytic degradation and adsorption efficiency of phenol and Sb(V) from textile wastewater were evaluated using this material. The results indicate that under conditions of pH 5.0 and a duration of 180 min, both phenol and Sb(V) removal rates exceed 90%. Characterization and experimental findings reveal that CIC possesses magnetic properties, facilitating easy separation, and offers a large surface area, ensuring abundant adsorption sites and stability. Additionally, CIC can assist in the enhanced degradation of phenol by H2O2. Pseudo-second-order kinetics describe the adsorption of Sb(V) by CIC, while oxidative kinetics explain the degradation of phenol. The primary removal mechanisms involve the oxidation and degradation of phenol through the generation of hydroxyl radicals by H2O2 and the formation of Fe-O-Sb complexes between Sb(V) and the iron sites on CIC, as well as the precipitation of Ca-O-Sb compounds between Sb(V) and the calcium sites on CIC. Therefore, the synergistic effect of CIC and H2O2 offers an efficient and environmentally friendly method for the simultaneous removal of Sb(V) and phenol in coupled wastewater, presenting broad prospects for application in wastewater treatment.

Bentonite/amino-functionalized cellulose composite as effective adsorbent for removal of lead: Kinetic and isotherm studies

In this study, bentonite/amino-functionalized cellulose composite (BAC) adsorbent was synthesized by intercalating the hexadecyl trimethyl ammonium bromide surfactant (HDTMA) into bentonite followed by exfoliating the HDTMA-modified bentonite (MB) into amino-functionalized cellulose (AC). The physicochemical properties of BAC were evaluated by FTIR, XRD, FE-SEM, EDX, TGA, and Zeta potential measurement. A series of batch mode adsorption experiments were carried out to identify the optimal adsorption conditions as a function of experimental variables such as pH of solution, uptake time, initial Pb2+ concentrations, BAC dosage, and assess both percent removal (%) and Pb2+ uptake (mg g−1). The result demonstrated that the synergetic advantage of combining HDTMA-modified bentonite (MB) and amino-functionalized cellulose (AC) in Pb2+ uptake (69 mg g−1) surpassed that of HDTMA-modified bentonite (12.14 mg g−1) and amino-functionalized cellulose (31.33 mg g−1) alone. Further, Pb2+ uptake onto BAC was higher than the HDTMA-modified bentonite/cellulose composite (BC) (42.12 mg g−1) due to the introduction of the amino group to cellulose through grafting with ethylenediamine (EDA). The adsorption of Pb2+ from aqueous solution by BAC fit well with pseudo - 2nd-order kinetic (R2 = 0.998) and Langmuir isotherm (R2 = 0.999) models. The kinetic study indicated that the active sites in the BAC exhibit heterogeneity and possess different activation energies for chemisorption. The monolayer attachment of Pb2+ onto the BAC surface was realized from the isotherm study, and the maximum predicted adsorption capacity was found to be 71.869 mg g−1. Regeneration studies showed that BAC maintained its good Pb2+ uptake capacity for up to four cycles.

Kinetic characteristics of methane hydrate formation under the synergistic effect of electric field and Hexadecyl trimethyl ammonium Bromide

Exploring hydrate formation methods with high gas storage capacity and high formation rate will be of great significance to the large-scale application of hydrate storage and transportation technology. The synergistic promotion of electric field and surfactant is an effective solution. In this work, the effects of sinusoidal alternating electric field and surfactant Hexadecyl trimethyl ammonium Bromide (CTAB) on the kinetics of methane hydrate generation were investigated. Methane hydrate formation kinetics experiments were conducted at different CTAB concentrations (0, 200, 500, 800 ppm) and voltages (0, 100, 500, 1000, 1500, 2000V) under the condition of 7 MPa and 275.15 K. The results showed that the synergistic effect of electric field and CTAB could effectively shorten the induction time of methane hydrate formation, greatly increase the formation rate, and improve the mobility of the generated hydrate. The downside was a slight decrease in gas storage capacity. A series of microscopic tests demonstrated that the introduction of electric field and CTAB did not change the crystal type of methane hydrate. This study was expected to provide new insights for rapid preparation of hydrates.

Ternary Mixed Micelle Hexadecyltrimethylammonium Bromide-Dodecyltrimethylammonium Bromide-Sodium Deoxycholate: Gibbs Free Energy of Mixing and Excess Gibbs Energy of Mixing.

Pharmaceutical, food, and cosmetic formulations often contain binary or ternary surfactant mixtures with synergistic interactions amongst micellar building blocks. Here, a ternary mixture of the surfactants hexadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, and sodium deoxycholate is examined to see if the molar fractions of the surfactants in the ternary mixed micellar pseudophase are determined by the interaction coefficients between various pairs of the surfactants or by their propensity to self-associate. Critical micelle concentrations (CMC) of the analyzed ternary mixtures are determined experimentally (spectrofluorimetrically using pyrene as the probe molecule). Thermodynamic parameters of ternary mixtures are calculated from CMC values using the Regular Solution protocol. The tendency for monocomponent surfactants to self-associate (lower value of CMC) determines the molar fractions of surfactant in the mixed micelle if there is no issue with the packing of the micelle building units of the ternary mixed micelle. If a more hydrophobic surfactant is incorporated into the mixed micelle, the system (an aqueous solution of surfactants) is then the most thermodynamically stabilized.

A liquid crystal-based sensor exploiting the aptamer-mediated recognition at the aqueous/liquid crystal interface for sensitive detection of serotonin.

We report here a liquid crystal (LC)-based sensor for detecting serotonin (5-HT); the proposed sensor uses target-specific aptamer recognition at a cationic surfactant decorated-aqueous/LC interface. Our detection strategy focuses on the orientational transition of LCs upon biological interactions at the interface. In this sensing system, the cationic surfactant hexadecyltrimethylammonium bromide (CTAB) forms a self-assembled monolayer at the aqueous/LC interface and triggers the homeotropic orientation of LCs. After introducing the 5-HT specific aptamer, an electrostatic attraction occurs between the cationic CTAB and anionic aptamer. This interaction destructs the surfactant monolayer at the interface, inducing reorganization of LC alignment from homeotropic to tilted conditions. In the increasing 5-HT levels, specific binding between 5-HT and the aptamer diminishes the interaction between the aptamer and CTAB, thereby maintaining the homeotropic alignment of LCs. The orientational transition of the LCs was observed under a polarized optical microscope. The developed biosensor has a linear detection range from 1 to 1000nM and a detection limit of 1.68nM. Moreover, the sensor was applied to a human urine sample and a detection limit of 2.25nM was obtained. Overall, the designed LC-based sensor is a sensitive, simple, cost effective, and selective platform for detecting 5-HT in aqueous solutions.

Functionalized Ordered Mesoporous MCM-48 Silica: Synthesis, Characterization and Adsorbent for CO2 Capture.

The ordered mesoporous silica MCM-48 with cubic Ia3d structure was synthesized using the cationic surfactant hexadecyltrimethylammonium bromide (CTAB) as a template agent and tetraethylorthosilicate (TEOS) as a silica source. The obtained material was first functionalized with (3-glycidyloxypropyl)trimethoxysilane (KH560); further, two types of amination reagents were used: ethylene diamine (N2) and diethylene triamine (N3). The modified amino-functionalized materials were characterized by powder X-ray diffraction (XRD) at low angles, infrared spectroscopy (FT-IR) and nitrogen adsorption-desorption experiments at 77 K. Characterization from a structural point of view reveals that the ordered MCM-48 mesoporous silica has a highly ordered structure and a large surface area (1466.059 m2/g) and pore volume (0.802 cm3/g). The amino-functionalized MCM-48 molecular sieves were tested for CO2 adsorption-desorption properties at different temperatures using thermal program desorption (TPD). Promising results for CO2 adsorption capacities were achieved for MCM-48 sil KH560-N3 at 30 °C. At 30 °C, the MCM-48 sil KH560-N3 sample has an adsorption capacity of 3.17 mmol CO2/g SiO2, and an efficiency of amino groups of 0.58 mmol CO2/mmolNH2. After nine adsorption-desorption cycles, the results suggest that the performance of the MCM-48 sil KH N2 and MCM-48 sil KH N3 adsorbents is relatively stable, presenting a low decrease in the adsorption capacity. The results reported in this paper for the investigated amino-functionalized molecular sieves as absorbents for CO2 can be considered as promising.

Facile Fabrication of Monodisperse Micron-Sized Dual Janus Silica Particles with Asymmetric Morphology and Chemical Environment.

Janus particles are a kind of materials with asymmetric morphology or surface chemical environment. But so far, the preparation of particles with dual asymmetry is still a challenging problem. Hence the cation surfactant hexadecyl trimethyl ammonium bromide and co-surfactant octadecylamine are applied to improve the Pickering emulsion stability, and the micron-sized silica particles are arranged in a single layer at the toluene-water interface through electrostatic interaction. Furthermore, organosilane reagents are added in the preparation process, resulting in the construction of asymmetric hydrophilic or hydrophobic mesoporous precisely onto the micron-sized silica particles surface. The cation surfactant-assisted Pickering emulsion method is simple, effective, and convenience, which can be applied in the synthesis of various dual Janus silica particles for specific applications.

Deterministic topological defects and quantum dot assembly in a nematic liquid crystalline medium

Liquid crystal (LC) materials exhibit interesting electro-optic switching and molecular ordering properties. Furthermore, the addition of chemically compatible active emitters such as core-shell quantum dots (QD) in a LC medium allows optical as well as dielectric tuning in an anisotropic, reconfigurable ordered medium. Order in a nematic LC phase is characterized by an orientational order parameter. In this work, we demonstrate the use of patterned substrates to generate arrays of integer topological defects in a nematic LC medium doped with cadmium selenide (core) cadmium sulfide (shell) core–shell QDs. We demonstrate the formation of metastable air-pillar-induced integer topological defects (TDs) in relatively thinner 9 μm LC sandwich cells, and the formation of field-induced TDs in thicker (25 μm) cells. Simultaneously, the self-assembly of core-shell QDs into square arrays on the patterned substrates is discussed, highlighting potential electro-optic device applications. The surfactant hexadecyltrimethylammonium bromide (CTAB) is found to play a significant role in LC TD formation as well as QD spatial organization at the optimized concentration. Self-assembly and ordering of single- and multi-component LCs within structured devices is a highly relevant problem for modern optoelectronic devices. This work opens new possibilities for classical as well as quantum light sources which require spatially ordered optical emitters in a reconfigurable dielectric medium at a micron-scale.

Molecular insight into interfacial tension modulated by mixed cationic and anionic surfactants

The oil/water interfacial tension plays a crucial role in tertiary oil recovery, and the low interfacial tension facilitates oil emulsification and stripping. Here, anionic surfactant sodium dodecyl sulfate and cationic surfactant hexadecyltrimethylammonium bromide were employed to study their ability to reduce the oil/water interfacial tension (IFT). Experimental results show that the mixed cationic and anionic surfactants could produce lower IFT than that of individual cationic or anionic surfactant, and the lowest IFT could be obtained at molar ratio of CTAB:SDS = 2:1. Employing molecular dynamics simulation method, the oil/water IFT was calculated and gave same changing trend with that of the experiment. The underlying mechanism of IFT modulated by mixed cationic and anionic surfactants was unveiled from the insight of interfacial structure, interfacial energy, interaction energy between different molecules and interface roughness, and so on. We found the hydration radius of counterion as well as the charge distribution of polar headgroup of surfactant together play crucial role determining the ion distribution inside water phase and surfactant/water interface, and further influencing the IFT. Our study provides an atomic-level understanding of the IFT modulated by cationic and anionic surfactants, and our results might have some references for enhanced oil recovery.

Molecular dynamics simulation of enhancing surfactant flooding performance by using SiO2 nanoparticles

In this study, four kinds of commonly used surfactants in oil fields, namely anionic surfactant sodium dodecyl sulfate (SDS), cationic surfactant hexadecyl trimethyl ammonium bromide (CTAB), nonionic surfactant primary alcobol ethoxylate (AEO-9) and zwitterionic surfactant dodecyl dimethyl carboxyl betaine (BS-12), were used as the research objects. The oil–water interfacial behaviors at different concentrations were studied by molecular dynamics simulation. Then, silica (SiO2) nanoparticles were combined with surfactant to observe the influence of nanoparticles on the configuration of surfactant monolayer, and to explore the optimal conditions for the synergistic flooding scheme of these nanoparticles and surfactant. The thickness and density of the oil–water interface layer, the radial distribution function (RDF) between the surfactant head group and water molecules, the mean square displacement (MSD) of water molecules around the surfactant head group, the oil–water interfacial tension (IFT) and the surfactant interface formation energy (IFE) were investigated. Surfactant flooding performance of different types and the effect of nanoparticles on surfactants were discussed. The results show that the surfactant with different ionic types have the best concentration in reducing the oil–water interfacial tension, and the interfacial tension is significantly reduced to 7.33 mN/m after adding nano-SiO2 particles in BS-12. After kinetic equilibrium, SDS and CTAB are arranged in an approximately regular manner, non-polar groups are inserted into the oil phase, polar groups extend into the aqueous phase, the long-chain head groups of AEO-9 molecules spread and stack at the interface, and BS-12 is irregularly distributed and some molecules are immersed in the oil phase. After adding nano-SiO2 particles, SDS, BS-12 and nano-SiO2 particles can be observed mutually repulsive in the interface morphology, while CTAB, AEO-9 and nano-SiO2 particles exhibit mutual attraction.

Evaluation of cilazapril release profiles with the use of lignin-based spherical particles

The main focus of this study is the preparation of lignin-based spherical particles as drug delivery systems. First, particles were prepared with the use of kraft lignin and the cationic surfactant hexadecyl (trimethyl)ammonium bromide (CTAB), and their physicochemical and structural characteristics were also determined. It was observed that the particles had a spherical shape and a low polydispersity index (PdI). The lignin particles were combined with the active compound cilazapril (CIL), and the system was tested for its drug-releasing ability. Cilazapril was combined with kraft lignin or lignin-based spherical particles to prepare different formulations. Mixtures with cilazapril as a reference (CIL-DB), kraft lignin (LIG-DB) and lignin-based spheres (LC-DB) were prepared with the use of a liquid base to obtain suspensions. The dialysis bag method was employed for the evaluation of drug release profiles. Release tests were performed at three pH values: 2.0, 5.8 and 6.8. It was observed that the lignin-based material is pH-sensitive, and better results were obtained at low or high pH values. The LC-DB formulation exhibited the best dissolution rates in all pH ranges. At pH 2.0, 5.8 and 6.8 the maximum release of cilazapril was around 80%, 62% and 90%, respectively. Lignin-based spherical particles enabled more efficient, sustainable and controlled release of cilazapril and may therefore have a potential for use in the medical industry, especially in drug delivery systems.

Thermal detection of second critical micelle concentration in SDS and CTAB aqueous solutions using a modified Lewis-Nielsen effective thermal model

When surfactant molecules are in solution, they self-assemble into various configurations, with the structural conformation changing upon concentration, temperature, and pH. The thermal transport of aqueous solutions containing anionic surfactant sodium dodecyl sulfate (SDS) and cationic surfactant hexadecyltrimethylammonium bromide (CTAB) was investigated using the thermal wave resonant cavity (TWRC) technique. We use the Lewis-Nielsen effective thermal conductivity model to explain the observed behavior in a new way. We consider that the form factor of the Lewis-Nielsen model relies entirely on surfactant concentration rather than being a constant, as initially was proposed by Lewis and Nielsen. Our findings indicate that the proposed method can detect the transition between spherical and rod-like surfactant micelles. Additionally, this technique could be used to calculate the thermal conductivity of surfactant molecules in water.

CTAB-mediated lithium disilicate branched structures as superb adsorbents to remove Mn2+ in water

Removal of heavy metal Mn2+ ions in water is of great importance for human health and it is urgently needed to develop efficient adsorption materials. Here, a green and effective strategy to prepare mesoporous micro/nanostructured lithium disilicates (LDs) by employing the cation surfactant hexadecyltrimethyl-ammonium bromide (CTAB) as morphology control agent in hydrothermal environment, and investigated its adsorption behavior toward Mn2+ ions. The LDs possessed branched structures that were consisted of scattering pyramidal rods bestrewn with secondary nucleated and aggregated nanoparticles. Due to the mesoporous structures and negatively charged surfaces, LDs exhibited a high adsorption capacity up to 346.84mgg−1 with corresponding removal efficiency up to 99.82% when initial Mn2+ concentration was 82mgL−1, and their maximum adsorption capacity reached up to 785.25mgg−1 toward Mn2+ of 250mgL−1. Results indicated that the isotherm adsorption behavior of LDs was well described by mono-layer Langmuir model and kinetic adsorption fitted well with pseudo-second-order model, implying them the excellent chemical adsorbent to remove Mn2+ from wastewater. We believe this CTAB-modified approach could be extended to prepare other lithium silicates with mesoporous structures, rendering them wider applications in environmental protection.

CTAB controlled electrochemical deposition of manganese dioxide with enhanced performance in aqueous Zn-ion battery

The collapse and dissolution of the structure of the MnO2 positive electrode in the cycle process is mainly caused by the volume expansion during the phase transition process, which leads to the extrusion of the adjacent parts of the electrode and poor cycle performance. To overcome this issue, morphology of MnO2 films were controlled by adding various concentrations of surfactant Hexadecyl trimethyl ammonium Bromide (CTAB) in the electrolytic cell through changing the current distribution characteristics between substrate and solution. The obtained MnO2 nanofilm materials prepared with different concentrations of surfactant were compared from the aspects of surface morphology, specific capacity and cyclic stability. The morphology and structure of the prepared MnO2 were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer Emmett and Teller (BET). As expected, MnO2 with its unique crystal structure exhibited excellent cycling and superior performance (311.2 mAh g−1 at 0.1 A g−1, 177.6 mAh g−1 at 5 A g−1, 125% capacity retention after 4000 cycles at 5 A g−1). This capacity retention was among the highest reported so far for MnO2-based cathode materials for Zn-ion batteries. The excellent electrochemical performance may be due to its unique nanostructure, which provides enough space for the volume expansion and proper structure for the re-deposition of MnO2. This work provides an new sight to develop long-circulation MnO2 electrodes for aqueous Zn ion batteries by designing an advantageous master structure dynamics.

Interactions between Nanoclay, CTAB and Linear/Star Shaped Polymers.

The influence of star-shaped (PAA-SS) and linear polyacrylic acid (PAA) with different molecular weights (high—PAA-HMW and low—PAA-LMW) on the structure of the adsorption layer, adsorption amount, electrokinetic and stabilizing properties of the PAA/CTAB/nanoclay suspensions was studied. The properties of the systems containing one of these polymers, the cationic surfactant—hexadecyltrimethylammonium bromide (CTAB) and the surface-modified nanoclay (N-SM) were analyzed using the following techniques: BET, CHN, FT-IR, ED-XRF, XRD, HRTEM, UV-Vis, tensiometry and zeta potential measurements. It was proved that PAA could be used as an effective stabilizer of N-SM. Moreover, the addition of CTAB caused a significant increase in the stability of the systems but decreased the adsorption of PAA on the N-SM surface and changed the structure of the adsorption layers. The largest stability was observed in the PAA-HMW/CTAB system. The PAA polymers and PAA/CTAB complexes adsorbed, especially on the clay surface, influenced the primary distribution of the layered sheets but kept the same basal d-spacing. The adsorption of PAA and the PAA/CTAB complexes took place mainly at the plate edges and on the contact space between the sheets. The obtained results will be used for the preparation of the PAA/CTAB/nanoclay composite for water purification.

Nitrate removal from contaminated waters using modified rice husk ash by Hexadecyltrimethylammonium bromide surfactant

Nitrate removal from contaminated waters using modified rice husk ash by Hexadecyltrimethylammonium bromide surfactant

Facile fabrication of hierarchical porous silicon/N-doped carbon composites via biomass fermentation treatment for high-performance lithium-ion batteries

Despite the ultrahigh theoretical capacity of Si anodes, their commercial application is severely restricted due to the lack of scalable and low-cost methods to overcome their considerable volume deformation and poor electrical connectivity. Herein, a novel hierarchical porous silicon/N-doped carbon composite (Si/N-PC) is successfully fabricated via simple biomass fermentation with inexpensive wheat flour, and this composite is then used as a high-performance lithium-ion battery (LIB) anode. Wheat flour blended with silicon nanoparticles can be fermented under the action of yeast while releasing carbon dioxide to construct a unique hierarchical porous structure. The added cationic surfactant hexadecyltrimethylammonium bromide not only helps uniformly deposit the Si particles in the wheat flour under the action of electrostatic forces but also forms an N-doped carbon layer in combination with the protein in the wheat flour, realizing full utilization of the raw materials. Systematic tests verify that the N-doped hierarchical porous structure contributes to mitigating the volume change, ensuring electrode stability and enhancing the electrical conductivity of the Si/N-PC composite during the charge-discharge process. As anticipated, the obtained Si/N-PC composite electrode can maintain a reversible discharge capacity of 696.1 mAh g−1 for over 300 cycles at a current density of 1 A g−1, exhibiting a 0.17% capacity loss per cycle from the 3rd to 300th cycle. Additionally, this composite electrode delivers a superior rate capability of 946.1 mAh g−1 at a high current density of 2 A g−1, showing the synergistic benefit of the hierarchical porous structure and N doping. This is the first time that a hierarchical porous silicon/N-doped carbon composite has been prepared via biomass fermentation treatment for use in high-performance LIBs. The overall fabrication process of the Si/N-PC composites is low cost and scalable, providing a sustainable strategy for the production of high-performance Si/C anode materials.