Cetyltrimethylammonium Bromide Template Research Articles

Pemanfaatan Lumpur Lapindo sebagai Sumber Silika Magnetik untuk Adsorpsi Tumpahan Crude Palm Oil

In this paper, synthesis of silica magnetite adsorbent has been carried out from Lapindo Mud silica and magnetite (Fe3O4) using the template Cetyltrimethylammonium bromide (CTAB) through a microemulsion process. This research aims to determine the adsorption ability of magnetic silica material as an adsorbent for Crude Palm Oil (CPO) with varying contact times of 10, 20, 30, 60, 90 minutes and an adsorbate concentration of 0,2, 0,4, 0,6, 0,8 and 1 gram. Silica is obtained from Lapindo Mud extraction using the acid leaching method using HCl. Magnetite was prepared by mixing ferric chloride and ferrous chloride salts with an alkaline base. Synthesis of magnetic silica adsorbent using CTAB and 1-butanol as a surfactant and co-surfactant, respectively. The characterization results from FTIR and SEM-EDX data identified the presence of silanol (Si-OH) and Fe-O groups, magnetic silica adsorbent showed an irregular morphological pattern, the size tended to be heterogeneous, contained Fe, O and Si elements. The XRD results show that there are peaks in the (200), (311) and (440) planes, the GSA results show that the pore surface area is 37.048 m2/g, the total pore volume is 0.321 cm3/g and the pore diameter is 33.907 nm, which indicates that the pores have a mesoporous structure. Based on this research, the optimum contact time is 60 minutes with adsorption kinetics following the pseudo-second order and Langmuir isotherm with an adsorption capacity of 1.76 mg/g.

Phosphorous, boron and sulphur-doped silver tungstate-based nanomaterials toward electrochemical methanol oxidation and water splitting energy applications

We employed a one-step precipitation approach to produce B, P, and S-doped Ag2WO4 (AgW) with the aid of a cetyltrimethylammonium bromide template in order to develop novel catalytic materials with components and architectures that tolerate harsh conditions. The P@AgW with the spherical (13.7 nm) shape was found to possess the greatest electrocatalytic activity for the oxidation of methanol in an acidic environment. It provides remarkable performance with an overpotential of 0.58 V (at a current density of 10 mA cm−2 comprised of mass activity of 1172 mA g−1) and considerable long-term reliability. This is attributed to the intense increase in the β-Ag2WO4/α-Ag2WO4 ratio (4:1), the formation of Ag–O–P, the highest electrochemical surface area, and the ease of charge transfer. The B@AgW electrode of polymorphic structure, on the other hand, performed the best for water electrolysis in the basic medium (1.0 M KOH). It produces an OER at overpotentials of 50 mA cm−2 at 0.42 V and 399 mV at 10 mA cm−2. At 10 mA cm−2, the HER overpotential was 0.33 V. Additionally, the B@AgW electrolyzer shows a cell voltage of 1.44 V for overall water splitting, which is lower than that of P@AgW (1.56 V), and it demonstrates great durability for 20 h. The notably higher activity of B@AgW compared to other electrolyzers is due to improved electrical conductivity, transport of mass, more active sites, and reduced particle size (7.2 nm). This work offers a simple way for the large-scale manufacture of electrocatalysts with considerable activity and reliability over time.

In Ukrainian

Regulation of enterohepatic circulation of bile acids in human body is actual task to overcome cardiovascular diseases. The aim of this work was to create biocompatible sorbents with improved sorption ability in relation to bile acids. Mesoporous organosilicas of MCM‑41 type with chemically grafted 3‑aminopropyl and steroid groups were obtained by sol‑gel condensation of tetraethyl orthosilicate and functional silanes in the presence of template cetyltrimethylammonium bromide. Porous structure of synthesized organosilicas was characterized by low‑temperature nitrogen adsorption–desorption and X‑ray diffraction analysis. Formation of typical for MCM‑41 hexagonal arrangement of cylindrical mesopores was confirmed. Structural parameters of synthesized silica materials were calculated. The influence of surface steroid groups on sorption ability of organosilicas was studied on example of bile salts (sodium cholate and taurocholate) in dependence of duration of contact, acidity of medium, and equilibrium concentration. Analysis of kinetic parameters of sorption estimated by Lagergren and Ho-McKey models confirms the proceeding of pseudo-second order process. The most effective sorption of sodium cholate and taurocholate was observed at pH ~ 5 and pH ~ 2, respectively, where the ovterlapping of pH regions of 3‑aminopropyl groups protonation and bile acids dissociation takes place. Analysis of experimentally obtained isotherms by use of Freundlich, Redlich‑Peterson, and BET models was carried out. It has been found that protonated amino groups are the main sorption centers of bile acids protolytic forms by synthesized aminosilica in pH range from 1 to 8. Introduction of steroid groups in surface layer at sol-gel synthesis leads to the increase of bile salts sorption due to the cooperative interactions with formation of supramolecular structures in the surface layer of organosilica. Obtained results prove prospects of usage of organosilica sorbents with surface steroid groups for regulation of bile acids content in human body.

Electrochemical Performance of Flower-like ZnO Nanostructure Crystal for Supercapacitor Electrode Applications

straightforward, easy and low-cost process using cetyltrimethylammonium bromide (CTAB) as a templated sonochemical production method was used to prepare ZnO nanostructures with the appearance of flowers. The morphological characteristics of ZnO materials have a more significant impact on variables like the CTAB template and sonochemical reaction time. The advantage of the flower-like ZnO materials is the more active reaction centre, which improves redox processes and results in outstanding electrochemical attributes like greater specific capacitance, excellent rate capability and better cyclic stability. The specific capacitance of the flower-shaped ZnO nanostructures (ZnO-2) from the cyclic voltammetric (CV) analysis was found to be 425 F g–1 at a scan rate of 5 mV s–1 and the charge/discharge study renders the specific capacitance is 426 F g–1 at a current density of 1 Ag–1. After 3000 CV cycles at a scan rate of 100 mV s–1, 89% of the initial capacitance still was retained in the long-term cyclic stability analysis. The distinctive flower-like ZnO nanostructures can be extended more for supercapacitor device applications.

Synergistic Effect, Structural and Morphology Evolution, and Doping Mechanism of Spherical Br-Doped Na3 V2 (PO4 )2 F3 /C toward Enhanced Sodium Storage.

Na3 V2 (PO4 )2 F3 has attracted wide attention due to its high voltage platform, and stable crystal structure. However, its application is limited by the low electronic conductivity and the ease formation of impurity. In this paper, the spherical Br-doped Na3 V2 (PO4 )2 F3 /C is successfully obtained by a one-step spray drying technology. The hard template polytetrafluoroethylene (PTFE) supplements the loss of fluorine, forming porous structure that accelerates the infiltration of electrolyte. The soft template cetyltrimethylammonium bromide (CTAB) enables doping of bromine and can also control the fluorine content, meanwhile, the self-assembly effect strengthens the structure and refines the size of spherical particles. The loss, compensation, and regulation mechanism of fluorine are investigated. The Br-doped Na3 V2 (PO4 )2 F3 /C sphere exhibits superior rate capability with the capacities of 116.1, 105.1, and 95.2mAhg-1 at 1, 10, and 30 C, and excellent cyclic performance with 98.3% capacity retention after 1000 cycles at 10 C. The density functional theory (DFT) calculation shows weakened charge localization and enhanced conductivity, meanwhile the diffusion energy barrier of sodium ions is reduced with Br doping. This paper proposes a strategy to construct fluorine-containing polyanions cathode, which enables the precise regulation of structure and morphology, thus leading to superior electrochemical performance.

Multifunctional Hybrid Nanoprobe for Photoacoustic/PET/MR Imaging-Guided Photothermal Therapy of Laryngeal Cancer.

Laryngeal cancer is highly aggressive and insensitive to conventional targeted therapies, which often result in poor therapeutic outcomes. Image-guided precision therapy is a promising strategy in oncology that has superior safety and efficacy versus conventional therapies. Here, we present a multifunctional theranostic nanoplatform based on melanin-coated gold nanorod (GNR) that exhibits excellent multimodal imaging ability and photothermal effects. These attributes make the platform applicable for multimodal photoacoustic (PA)/positron emission tomography (PET)/magnetic resonance (MR) image-guided photothermal treatment of laryngeal cancer. The melanin nanoparticles markedly suppress the cytotoxicity of the template cetyltrimethylammonium bromide bilayer and conferred the GNR with excellent PET/MR imaging performances, due to their native biocompatibilities and strong affinities to metal ions. Moreover, the introduction of GNR to the melanin nanoparticles greatly improved the near-infrared absorbances and passive targeting capabilities, leading to exceptional PA imaging and photothermal ablation of tumors. The nanoplatform exhibits high stability and dispersity under physiological conditions. After intravenous injection, the nanoplatform could be precisely tracked in vivo and enabled laryngopharyngeal superficial cancer to be located and imaged. Combined photothermal therapy effectively ablated tumors with negligible side effects. Thus, this work presents a unique and biocompatible nanoplatform that allows multimodal imaging, high anti-tumor PTT efficacy, and negligible side effects in the treatment of laryngeal cancer.

Gold@Silver bimetallic nanoparticles: fabrication and removal of toxic chromium(VI)

Gold@Silver bimetallic nanoparticles (Au@Ag NPs) were fabricated by using galvanic displacement reaction with soft template cetyltrimethylammonium bromide (CTAB). UV–visible spectroscopy, TEM, EDX, and XRD used to determine the morphology of Au@Ag NPs. The surface plasmon resonance (SPR) band position strongly depends on the ratio of metal salt precursors. Au@Ag employed as an adsorbent to the chromium(VI) removal from an aqueous solution. Effects of adsorption time, pH, temperature, the dose of Au@Ag, and concentration of chromium(VI) were studied and the removal percentage was calculated. Langmuir adsorption monolayer, Freundlich, intraparticle diffusion, and multilayer adsorption isotherms were used for the determination of maximum adsorption efficiency and adsorption isotherm parameters. The kinetics of chromium(VI) removal have also been discussed with various kinetic rate laws. Chromium (VI) adsorption followed Langmuir isotherm and the pseudo-second-order model with the highest linear regression coefficient.

Several Shapes of Single Crystalline Gold Nanomaterials Prepared in the Surfactant Mixture of CTAB and Pluronics.

Twin structures in gold nanomaterials are destined because they reduce the severe strains in the misfit region of nanostructures. Defect-free single crystalline plasmonic nanomaterials gain interests these days as the integration of plasmonic materials or plasmons into electronic devices and circuits becomes more common. In this study, without subtle experimental adjustments, such as pH or halide additives, several shapes of single crystalline gold nanoparticles (NPs) are prepared in the surfactant mixture of cetyltrimethylammonium bromide (CTAB) and Pluronic triblock copolymers. The synthesized NPs are primarily composed of {100} planes with small numbers of particles possessing a [110] zone axis. Pluronic copolymers with low number average molecular weights (Mn), such as L-31 (Mn ≈ 1100) and L-64 (Mn ≈ 2900), prefer anisotropic nanorods with the aspect ratios of 4.3 and 3.0, respectively, while Pluronics with high Mn values, such as F-68 (Mn ≈ 8400) and F-108 (Mn ≈ 14 600), favor more concentric and isotropic cube-like NPs. Extended micelles are believed to form in Pluronics with low Mn values in which hydrophobic cores are merged with the increase of temperature, while the corona regions that are composed of long tails of PEO prevent the merge of hydrophobic cores, and the growth of the micelles is limited in Pluronic copolymers with high Mn values. The catalytic degradation reactions of methyl orange are conducted, and rather than isotropic particles, gold nanorods exhibit better catalytic performances. More hydrophilic environment and the steric alignment of rigid aromatic structures of methyl orange along the nanorods are thought to contribute to the catalytic activities. Overall, highly confined geometries of the appropriately swollen micellar templates of Pluronics and CTAB, which is not so hydrophobic as for the formation of contracted deswollen templates and for the inhibition of the growth of NPs, and which is not so hydrophilic as for the formation of coarse templates and for the formation of isotropic spheres with varying sizes, are believed as the main factor for the formation of single crystalline gold NPs.

Reduced cytotoxicity of CTAB-templated silica layer on gold nanorod using fluorescence dyes and its application in cancer theranostics

Cytotoxicity of cetyltrimethylammonium bromide (CTAB)-templated silica-coated gold nanorod (CGNR@SiO2) was confirmed to be severe even after the washing process because of the residual CTAB surfactant. Calcination to eliminate the CTAB template induced dissolution of the gold nanorod (GNR) core and caused a blue-shift in the longitudinal surface plasmon resonance (LSPR) mode of the GNR from the near-infrared to visible wavelength. In contrast, the CTAB template was effectively removed from CGNR@SiO2 without interference of the plasmonic property of the core GNR by amine-functionalized fluorescence dyes such as methylene blue (MB) and rhodamine B (RB). The RB was more efficient in substituting the residual CTAB through electrostatic interactions than the MB. Moreover, the resulting products exhibited excellent surface-enhanced Raman scattering performance to detect a few cancer cells. The MB and RB molecules as visible light photosensitizer (PS) were activated by near-infrared (NIR) excitation light through transfer of the NIR-driven plasmonic hot electrons from the core GNR to the PS molecules. It is noteworthy that the RB-loaded CGNR@SiO2 exhibited excellent cancer cell killing efficiency via generation of abundant reactive oxygen species (ROS) under NIR laser irradiation, although the concentration of the intracellular GNR was too low to induce the photothermal effect.

Enhancing propene selectivity in methanol and/or butene conversion by regulating channel systems over ZSM-5/ZSM-48 composite zeolites

Abstract ZSM-5/ZSM-48 composite zeolite was synthesized via an one-pot method by using mixed templates of cetyltrimethyl ammonium bromide (CTAB) and 1,6-hexamethylenediamine (HDA), and its catalytic performance was tested in methanol-to-olefin reaction (MTO), butene conversion and co-reaction of methanol with butene. The results show that the amount of added CTAB plays a vital role in the synthesis of ZSM-5/ZSM-48 composite zeolite. The increase in the amount of CTAB in the synthesis gels leads to an increase in the content of zeolite with MFI structure, a higher specific surface area, more Al atoms located at channel intersections and more acid sites than ZSM-48 synthesized by the conventional method with HDA as a template. The catalytic results show that ZSM-5/ZSM-48 composite zeolite gives much higher propene selectivity in MTO reaction, butene conversion and co-reaction compared with ZSM-5, ZSM-48 and their mechanical mixtures due to that the combined effect of catalyst acidity and pore structure promotes the olefin-based cycle and inhibits the aromatization and hydride transfer reactions.

A facile route to synthesize CuO sphere-like nanostructures for supercapacitor electrode application

The sphere-like nanostructure has been developed using the cetyl trimethyl ammonium bromide (CTAB) template-assisted simple co-precipitation method subsequently succeeded by an effective heat treatment. The surface morphological features of the CuO materials can be easily tuned using various concentrations of the CTAB template. The thermal behavior, phase and bonding characteristics were analyzed using thermogravimetric analysis (TGA), Scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD) and Fourier transform infrared spectroscopic (FTIR) analyses. The morphological study declares that the prepared CuO has aggregated definitely shaped nanoparticles and sphere-like nanostructure morphologies. The sphere-like nanostructure exhibits large reaction centers, which permits well electrolyte accessible and provide the shortest path for ions. The electrochemical performance of the materials has been studied using cyclic voltammetric (CV) and galvanostatic charge/discharge (GCD) analysis. The sphere-like CuO nanostructure delivers 494 F g−1 as the specific capacitance at a scan rate of 5 mV s−1 whereas the GCD curves provide the specific capacitance of 468 F g−1 at a current density of 1 A g−1. The retainment of 94% of the initial capacitance after 2000 cycles of CV curves at a scan rate of 100 mV s−1 reveals the cyclic stability studies. The present study recommends the synthesis of low-cost CuO material and its fine-tuning surface characteristics to be very much essential for energy storage applications.

Mesoporous Silica Encapsulated Metal-Organic Frameworks for Heterogeneous Catalysis

Encapsulation of metal-organic frameworks (MOFs) with a shell of mesoporous silica can boost overall performance of MOFs, offering versatility for synthetic architecture of integrated nanocatalysts with reactor-like features. Recently, Yu et al. report a green approach to make yolk-shell nanoreactors.

Fast responsive thermally stable silica microspheres for sensing evaluation: sol–gel approach

Cetyltrimethylammonium bromide (CTAB) micelle-templated mesoporous SiO2 particles (MSPs) are synthesized by sol–gel method. The CTAB templated SiO2 particles (SPs) possessed spherical structure with low average surface roughness (Ra) 1 nm. The CTAB template is effectively removed from SPs by 400 °C heat treatment without any cracks and disruption of the bonding between the functional groups and the SiO2 surface. After CTAB template removal, SiO2 microspheres (SMSs) possessed high surface area 640 m2/g, pore radius 10 nm, and Ra ~ 4.4 nm, making them highly attractive for sensing. Thermal gravimetric analysis (TGA) confirmed that SMSs are thermally stable, showing 0.7% weight loss after 429 °C temperature. Phenol red immobilized SMSs show large pKa value 8.1 at 560 nm. Good repeatability, no leaching traces, and fast response time ~0.09 s in basic media suggested that proposed material has potential for opto-chemical sensing/photonic applications.

Influence of swelling agents on pore size distributions of porous silica-alumina hollow sphere particles in acid-promoted hydrolytic generation of hydrogen from ammonia borane

We studied the influence of swelling agents on pore size distributions in the shell of porous silica-alumina hollow sphere particles for acid-promoted hydrolytic generation of hydrogen from ammonia borane. Their well-ordered porous shells were formed with micelle templates of cetyltrimethylammonium bromide on spherical polystyrene (PS) particle templates, and swelling agents were introduced into the micelle templates for expanding the pores. Non-polar agents (hexane and toluene) did not significantly influence the size of the pores, whereas, polar agents (1-dodecanol and 1-dodecylamine) effectively expanded the pores. The hollow sphere particles formed with 1-dodecylamine possessed narrow pore distribution with a high peak pore volume. The activity of the hollow sphere particles in the hydrolytic generation of hydrogen increased according to increasing pore size with a narrow distribution, and the hollow sphere particles formed with 1-dodecylamine showed an approximately five times higher TOF for the hydrogen evolution than those formed without a swelling agent.

A robust method for fabrication of monodisperse magnetic mesoporous silica nanoparticles with core-shell structure as anticancer drug carriers

This paper presents a novel method based on an inverse microemulsion system to synthesize monodisperse magnetic mesoporous silica nanoparticles (MMSN) with core-shell structure. In this method, the water-in-oil microemulsion system was prepared using of cyclohexane containing silica precursor as a continuous oil phase, discrete water droplets containing magnetic seeds (Fe3O4 nanoparticles) and urea as an aqueous phase, and cetyltrimethylammonium bromide (CTAB) and 1-butanol as a surfactant and co-surfactant, respectively. Unlike the traditional reverse microemulsion method, the magnetic seeds used in this system were first covered by a self-organized two-layer surfactant including oleic acid and CTAB as a good host for silica formation. Hence, by removing the CTAB template from the silica structure, a mesoporous silica shell remains on the surface of Fe3O4 nanoparticles. The effects of catalyst types (urea and NaOH), TEOS content, and reaction temperature on the morphology and size of the prepared samples were investigated. It was found that by rising the reaction temperature from 70 to 120 °C, the thickness of the silica layer was increased from 3 to 17 nm. Moreover, a thicker silica coating (26 nm) was obtained by increasing the TEOS content. Also, the performance of the prepared nanocomposite for drug delivery applications was investigated using 5-fluorouracil (5-Fu) as a drug model in a physiological medium. The obtained results showed that the prepared magnetic mesoporous silica nanocomposite has great potential for biomedical applications.

Novel scheme for rapid synthesis of hollow mesoporous silica nanoparticles (HMSNs) and their application as an efficient delivery carrier for oral bioavailability improvement of poorly water-soluble BCS type II drugs.

Hollow mesoporous silica nanoparticles (HMSNs) are one of the most promising carriers for drug delivery. However, a facile method to synthesize HMSNs has hardly been reported so far. The primary objective of our current study was to develop HMSNs using a simple, quick, and inexpensive method and evaluate their ability to enhance solubility, dissolution rate, and bioavailability of poorly water-soluble model BSC type II drug Carvedilol. Traditional mesoporous silica nanoparticles (MSNs) are synthesized using classical Stober method and HMSNs with an entire hollow core was induced by immersing cetyltrimethylammonium bromide (CTAB) in hot water. Initial MSNs were added in boiling distilled water to synthesize hollow structure, to enhance pore size, and also to remove CTAB template. HMSNs prepared in our current study has exhibited high surface area (886.84 m2/g), pore volume (0.79 cm3/g), and uniform pore size (3.18 nm), which also enabled the greater encapsulation of the model BSC II drug Carvedilol (CAR) inside the HMSNs. This technique also helped in achieving a high drug loading of (40.22 ± 0.73)%. Add to all this, in vitro studies conducted in the present work showed that compared with pure CAR and CAR loaded MSNs (CAR-MSNs) synthesized by Stober method, the drug-loaded HMSNs (CAR-HMSNs) exhibit sustained drug release performance. The high drug loading and sustained release can be attributed to the hollow porous structure of the HMSNs. Finally, a pharmacokinetic analysis in rats indicated a significant increase in bioavailability of carvedilol HMSNs in vivo compared to the pure carvedilol and carvedilol loaded MSNs. This study, therefore, offered a new, simple, and quick method to develop HMSNs with the ability to support higher loading and controlled release behavior in vitro and enhanced absorption of poorly-aqueous soluble drugs in-vivo.

Influences of cetyltrimethyl ammonium bromide template on photocatalytic degradation of ofloxacin on porous La2Ti2O7

Influences of cetyltrimethyl ammonium bromide template on photocatalytic degradation of ofloxacin on porous La2Ti2O7

Polyethylene glycol-coated porous magnetic nanoparticles for targeted delivery of chemotherapeutics under magnetic hyperthermia condition

Purpose: Although magnetite nanoparticles (MNPs) are promising agents for hyperthermia therapy, insufficient drug encapsulation efficacies inhibit their application as nanocarriers in the targeted drug delivery systems. In this study, porous magnetite nanoparticles (PMNPs) were synthesized and coated with a thermosensitive polymeric shell to obtain a synergistic effect of hyperthermia and chemotherapy.Materials and methods: PMNPs were produced using cetyltrimethyl ammonium bromide template and then coated by a polyethylene glycol layer with molecular weight of 1500 Da (PEG1500) and phase transition temperature of 48 ± 2 °C to endow a thermosensitive behavior. The profile of drug release from the nanostructure was studied at various hyperthermia conditions generated by waterbath, magnetic resonance-guided focused ultrasound (MRgFUS), and alternating magnetic field (AMF). The in vitro cytotoxicity and hyperthermia efficacy of the doxorubicin-loaded nanoparticles (DOX-PEG1500-PMNPs) were assessed using human lung adenocarcinoma (A549) cells.Results: Heat treatment of DOX-PEG1500-PMNPs containing 235 ± 26 mg·g−1 DOX at 48 °C by waterbath, MRgFUS, and AMF, respectively led to 71 ± 4%, 48 ± 3%, and 74 ± 5% drug release. Hyperthermia treatment of the A549 cells using DOX-PEG1500-PMNPs led to 77% decrease in the cell viability due to the synergistic effects of magnetic hyperthermia and chemotherapy.Conclusion: The large pores generated in the PMNPs structure could provide a sufficient space for encapsulation of the chemotherapeutics as well as fast drug encapsulation and release kinetics, which together with thermosensitive characteristics of the PEG1500 shell, make DOX-PEG1500-PMNPs promising adjuvants to the magnetic hyperthermia modality.

Role of cetyltrimethyl ammonium bromide on sol–gel preparation of porous cerium titanate photocatalyst

Cetyltrimethyl ammonium bromide (CTAB) was used as template agent to prepare porous cerium titanate by sol–gel method. Besides major brannerite CeTi2O6 in monoclinic system, the addition of CTAB template leads to formation of minor anatase TiO2 and CeO2 phases. FT-Far-IR spectra also prove Ce-O and Ti-O-Ti bonds in the porous cerium titanate. The addition of CTAB template in the precursor can obviously enlarge BET surface area and pore volume of cerium titanate. Removal of CTAB template during calcination leaves mesoporous structure in the cerium titanate samples, which are presented in the N2 adsorption-desorption isotherms. Not only more hydroxyl radicals can be produced on the samples obtained using CTAB, but also photocatalytic oxidation efficiency is strongly influenced by the variation of CTAB amount. The reaction rate constant is 2.44 × 10−2 min-1 on the porous cerium titanate sample obtained using 2 g CTAB, while the reaction rate constant is only 9.60 × 10−3 min-1 on the sample without CTAB. UV-Visible spectra of ofloxacin solution during photocatalytic oxidation demonstrate the degradation of typical organic groups in ofloxacin molecule.

Synthesis, characterization, and catalytic performance of hierarchical ZSM-11 zeolite synthesized via dual-template route

Hierarchical zeolite materials were prepared via one-pot synthesis of ZSM-11 zeolites with different molar ratios (R) of a mesoporogen, i.e., cetyltrimethylammonium bromide template (CTAB), to a microporogen, i.e., tetra-n-butylammonium bromide (TBABr). The structures, morphologies, and textural properties of the resultant materials were investigated. Initially, with increasing R, the crystal size of the synthesized product decreased, the number of intercrystalline mesopores increased, and a pure ZSM-11 zeolite phase was present. Then an MCM-41-like phase was produced and embedded in the ZSM-11 zeolite phase. Finally, an MCM-41-like phase was obtained. The alkalinity had important effects on the physicochemical and textural properties of the prepared samples. A possible mechanism of formation of the hierarchical ZSM-11 zeolite was proposed on the basis of a combination of various characterization results. The role of CTAB varied depending on the R value, and it showed a capping effect, micellar effect, and template effect. These effects of CTAB were synergetic in ZSM-11 synthesis, but they were competitive with the structure-directing effect of TBABr. In addition, the impact of the acidic properties and porosities of the hierarchical ZSM-11 catalysts on their performances in the alkylation of benzene with dimethyl ether was investigated.