3-glycidyloxypropyl Trimethoxysilane Research Articles

Hybrid Adhesives Filled with Functionalized and Non Functionalized Silica Nanoparticles

Hybrid adhesives epoxy-silica-zirconia were prepared and applied to bond aluminum sheet specimens. Silica nanoparticles were synthesized with the sol-gel “in situ” technique utilizing two different precursors, namely tetraethyl orthosilicate (TEOS) and 3 glycidyloxypropyltrimethoxysilane (GPTMS). Zirconia nanoparticles were prepared also with sol-gel technique and added to the hybrid adhesives before curing. The adhesive properties of the prepared materials were improved after performing several physical and chemical treatments to the aluminium specimens. The best apparent shear strength tests were for the adhesive hybrid materials prepared at 100°C with TEOS.

Soft-Pillared@Magadiite: influence of the interlayer space and amine type on CO2 adsorption.

Layered silicates are versatile materials that can be grafted with different organosilanes for several applications. Despite this, there are few studies on the use of layered silicate-based materials in CO2 adsorption. In this regard, the present study describes the synthesis of organo-magadiite followed by simultaneous grafting with two organosilanes ((3-glycidyloxypropyl)trimethoxysilane (GPTS) and N1-(3-trimethoxysilylpropyl)diethylenetriamine (TMSPETA)) to prepare an adsorbent labeled Soft-Pillared@Magadiite. The adsorbents were characterized through XRD, 13C- and 29Si-NMR, TGA/DTG, and elemental analyses of carbon, hydrogen, and nitrogen (CHN). The results suggest that this adsorbent has an expanded interlayer space (3.05 nm) that is larger than the interlayer space when the layered material is grafted with the organosilanes separately, and it may display improved CO2 adsorption. The CO2 adsorption was evaluated by TGA, CO2-TPD, and DSC. Moreover, the adsorption isotherms were fitted using a pseudo-second order, a fractional order, and Avrami models. The optimum adsorption temperature of Soft-Pillared@Magadiite was 25 °C, and the adsorption capacity and efficiency were 0.36 mmol g-1 and 0.15, respectively, obtained using 5 vol% CO2 in He for 3 h. The CO2-TPD shows that the desorption of CO2 occurs below 90 °C, and from DSC, it is found that thermodynamic parameters, specifically sensible heat and heat of regeneration, are low as compared to those of aqueous MEA solution; the current technology indicates that Soft-Pillared@Magadiite has a good potential for CO2 adsorption.

Self-Healing Effect of Hybrid Sol-Gel Coatings Based on GPTMS, TEOS, SiO2 Nanoparticles and Ce(NO3)3 Applied on Aluminum Alloy 7075-T6

Aluminum alloy AA7075-T6 is most commonly used in the aircraft and automotive industries. Due to the presence of intermetallic particles, AA7075-T6 is susceptible to localized corrosion in chloride solutions. In the present work multilayer hybrid sol-gel coatings, based on silane precursors 3-glycidyloxypropyl(trimethoxysilane) (GPTMS) and tetraethoxysilane (TEOS), were used to protect AA7075-T6 from corrosion. To enrich the barrier properties of the coating, SiO2 nanoparticles were added to the GPTMS/TEOS sol-gel solution. Inhibition and a self-healing effect were achieved by doping Ce(NO3)3 in the coating. A multi-layer system was applied on the substrate composed of a first layer doped with Ce(NO3)3 and the second, undoped sol-gel layer. The addition of cerium increases the lifespan of hybrid sol-gel coating and has a role in self-healing if it is locked within the first layer of the multilayer coating. The self-healing effect was confirmed by immersion of unscribed and scribed coated substrates in 0.1 mol/L NaCl by using the immersion test, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy with chemical analysis.

Exploring electrochemical reactivity toward ametryn of hybrid silicate films with phosphomolybdic acid

This paper describes the synthesis of organically-modified silicates (ormosils) with phosphomolybic acid (HPMo), and their use to detect ametryn. Gold electrodes coated with an ormosil film made of 3-cyanopropyltriethoxysilane (CPTS) and HPMo were used to detect ametryn between 3.5 and 24 µmol L−1 in an acidic medium. There was no evidence of electroreduction of ametryn when ormosils with HPMo and (3-glycidyloxypropyl)trimethoxysilane (GLPTS) or 3-aminopropyltriethoxysilane (APTS) were used. This difference in behavior is ascribed to aggregation in CPTS ormosil, while GLPTS and APTS ormosils displayed homogeneous surfaces, according to scanning electron microscopy. HPMo had its structure preserved in CPTS ormosil as indicated by 31P solid-state nuclear magnetic resonance spectra. Using polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS), we inferred that the functional group dipole moments in all ormosils are oriented parallel to the interface. Control of morphology thus seems essential for applications of ormosil films, being particularly promising to monitor environmentally-relevant herbicides.

The Effect of Different Coupling Agents on Nano-ZnO Materials Obtained via the Sol–Gel Process

Hybrid nanomaterials based on zinc oxide were synthesized via the sol–gel method, using different silane coupling agents: (3-glycidyloxypropyl)trimethoxysilane (GPTMS), phenyltriethoxysilane (PhTES), octyltriethoxysilane (OTES), and octadecyltriethoxysilane (ODTES). Morphological properties and the silane precursor type effect on the particle size were investigated using dynamic light scattering (DLS), environmental scanning electron microscopy (ESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The bonding characteristics of modified ZnO materials were investigated using Fourier transform infrared spectroscopy (FTIR). The final solutions were deposited on metallic substrate (aluminum) in order to realize coatings with various wettability and roughness. The morphological studies, obtained by ESEM and TEM analysis, showed that the sizes of the ZnO nanoparticles are changed as function of silane precursor used in synthesis. The thermal stability of modified ZnO materials showed that the degradation of the alkyl groups takes place in the 300–500 °C range. Water wettability study revealed a contact angle of 142 ± 5° for the surface covered with ZnO material modified with ODTES and showed that the water contact angle increases as the alkyl chain from the silica precursor increases. These modified ZnO materials, therefore, can be easily incorporated in coatings for various applications such as anti-corrosion and anti-icing.

Optimization of binding B-lymphocytes in a microfluidic channel: surface modification, stasis time and shear response

Binding and maintaining cells inside microfluidic channels is a challenging task due to the potential release of cells from the channels with the flow and accompanying shear stress. In this work we optimized the binding of human B-lymphocyte cells (HR1K) inside a microfluidic channel and determined the strength of this binding under shear stress of flowing liquid. In order to determine the parameters required for a live/dead test in microfluidic devices, populations of both living and dead cells were tested separately. Channels were prepared in glass-polydimethylsiloxane hybrid chips, with a self-assembled monolayer of 3-(glycidyloxypropyl)trimethoxysilane (GPTMS) before covalently immobilizing anti-CD20 antibody. Without GPTMS linker, ∼90% of the CD20-expressing cells detached at 200 μl min−1 (the highest flow rate studied). With GPTMS linker, the bonding method proved critical for sustained immobilization of HR1K cells under flow. Masking the channel area during plasma bonding preserves the antibody functionality; the masked surface gives 15% cell detachment at 200 μl min−1 compared with 80% for an unmasked surface. Sealing the chip via clamping (without plasma treatment) was similar to masked plasma treatment (20% detachment) and allowing a post-adhesion stasis time (30 min) did not significantly change the relative cell detachment for the flow rates studied. Membrane integrity and calcium spiking behaviour were measured fluorescently, and demonstrated that the live cells retained comparable functionality to unanchored cells for the duration of the flow experiments. Non-viable HR1K cells were found to detach more readily, exhibiting only 20% cell retention at 200 μl min−1 compared with >80% for live cells.

Low-temperature poly(oxymethylene) direct bonding via self-assembled monolayer

A direct bonding of poly(oxymethylene) (POM) was feasible at 100 °C by using self-assembled monolayer (SAM) as a surface modification method. (3-aminopropyl)triethoxysilane (APTES) and (3-glycidyloxypropyl)trimethoxysilane (GOPTS) were used in our work. X-ray photoelectron spectroscopy showed that both APTES and GOPTS modified the POM surface successfully. Bonding strength evaluation revealed that surface modification was affected by pretreatment (VUV/O3) process time. In addition, the bonding condition with highest strength had an average strength of 372 kPa. This technology is expected to be used in packaging for micro-/nano-electromechanical systems, such as biomedical devices.

Hybrid custom-tailored sol-gel derived microscaffold for biocides immobilization

The present paper regards the development of silica-epoxy matrices, in the form of functional spherical microscaffolds with controlled morphology, comprising an immobilized biocide, for antifouling purposes. The microscaffolds herein presented were obtained from sol–gel processing combined with a microemulsion technique, using as Si precursors, tetraethylorthosilicate (TEOS) and 3-glycidyloxy propyl trimethoxysilane (GPTMS) to be further loaded with biocide Econea®, which has been approved in 2014 by EU Regulator (BPR) as a safe biocide. Biocide immobilization is proposed to be carried out by chemical grafting mainly between the microscaffolds' oxirane ring and the secondary amino groups of the biocide Econea®, as well as by physical entrapment within the “worm-like” morphology and multimodal pore size distribution of the microscaffolds. The presence of Econea® within the microscaffolds was confirmed by Fourier transformed infrared spectroscopy (FTIR), thermogravimetric analyses and scanning electron microscopy (SEM-EDX) and it was found to be nearly constant over the time when those are immersed in artificial seawater, while under mild agitation. The biocidal effect of the Econea® loaded silica-epoxy spherical microscaffolds was assessed by microbiological tests, exhibiting an effective activity against Staphylococcus aureus bacteria, by contact mode, even after exposure to turbulent saline water. These microscaffolds were designed for enabling a more environmental friendly anti-fouling strategy, able to combine a more efficient, long-lasting antifouling performance for water-immersed applications, together with non-toxic properties, being, therefore, a promising and attractive alternative to the actual conventional releasing strategies.

Borosilicate Glass Fiber-Optic Biosensor for the Detection of Escherichia coli.

Polyclonal antibodies against Escherichia coli and fluorescent, secondary, antibodies were immobilized on borosilicate glass fibers pre-treated with 3-glycidyloxypropyl trimethoxysilane (GPS). Light with an average wavelength of 627nm, emitted by a diode placed at one end of the glass fiber, was detected by an ultrasensitive photodiode with peak sensitivity at 640nm. Changes in fluorescence, caused by binding of E. coli to the antibodies, changed the net refractive index of the glass fiber and thus the internal reflection of light. These evanescent changes in photon energy were recorded by an ultrasensitive photodiode. Signals were amplified and changes in voltage recorded with a digital multimeter. A linear increase in voltage readings was recorded over 2h when 3.0×107 CFU/ml and 2.77×109 CFU/ml E. coli were adhered to the antibodies. Voltage readings were recorded with E. coli cell numbers from 2×103 CFU/ml to 2×106 CFU/ml, but readings remained unchanged for 2h, indicating that the limit of detection is 3.0×107 CFU/ml. This simple technology may be used to develop a low-cost, portable, fiber-optic biosensor to detect E. coli in infections and may have applications in the medical field. Research is in progress to optimize the sensitivity of the fiber-optic biosensor and determine its specificity.

Influence of chemical treatments on mechanical properties of hemp fiber reinforced composites

Abstract Natural Fibers Reinforced Composites (NFRC) are finding much interest as a substitute for glass or carbon reinforced polymer composites, like for instance automobile interior linings (roof, rear wall, side panel lining), shipping pallets, construction products (i.e. composite roof tiles), furniture and household products (i.e. storage containers, window and picture frames as well as food service trays, toys and flower pots) as well as fan houses and blades. However, a notable disadvantage of lignocellulosic fibers as reinforcements is their polarity which makes it incompatible with hydrophobic thermoplastic matrix. This incompatibility results in poor interfacial bonding between the fibers and the matrix. This in turn leads to impaired mechanical properties of the composites. This defect can be remedied by chemical modification of fibers so as to make it less hydrophilic. In this paper experiments have been performed to further the development of natural fiber reinforced composites. Untreated and treated surfaces of hemp fibers were characterized using Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM). Fiber-matrix adhesion was promoted by fiber surface modifications using an alkaline treatment and (3-Glycidyloxypropyl) trimethoxysilane coupling agent. The mechanical behaviour of epoxy matrix composite reinforced with woven hemp was studied and mechanical test results show that silane treatment of hemp fibers improves, both tensile and flexural properties of the composites, although no high values are obtained.

Enhanced Dielectric Properties of Polyimide Matrix Using Modified Electrospun Barium Titanate Nanofibers

Recently, many researchers focus on the nanoscale fillers to enhance electrical properties of composite due to the uniqueness of material. In this study, polyimide/barium titanate (BaTiO3) nanofibers films were prepared by incorporating electrospun BaTiO3 nanofibers with polyimide derived from 2,2-Bis [4-(4-aminophenoxy) phenyl] propane (BAPP) and 3,3',4,4'-Biphenyl tetracarboxylic dianhydride (BPDA). The obtained nanofibers were modified with (3-Glycidyloxypropyl) trimethoxysilane as coupling agent before integrating into the polyimide matrix. Microstructure and dielectric properties of BaTiO3 nanocomposites were investigated. The results showed BaTiO3 nanofibers were successfully produced at nanoscale regime and well dispersed in the hybrid film after modification and ultrasonication method. Dielectric constant of the nanofibers films were improved and increased with increasing of BaTiO3 nanofibers concentration while dielectric loss remains relative low.

Poly(3,4-ethylenedioxythiophene)-Based Nanofiber Mats as an Organic Bioelectronic Platform for Programming Multiple Capture/Release Cycles of Circulating Tumor Cells.

In this investigation, we employed a novel one-step electrospinning process to fabricate poly(ethylene oxide) (PEO)/poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) core/shell nanofiber structures with improved water resistance and good electrochemical properties and characterized them using scanning electron microscopy, transmission electron microscopy, and time-of-flight secondary ion mass spectrometry imaging. We then integrated a biotinylated poly-(l-lysine-graft-ethylene glycol) (PLL-g-PEG-biotin) coating with three-dimensional (3D) PEDOT-based nanofiber devices for dynamic control over the capture/release performance of rare circulating tumor cells (CTCs) on-chip. The detailed capture/release behavior of the circulating tumor cells was studied using an organic bioelectronic platform comprising PEO/PEDOT:PSS nanofiber mats with 3 wt % (3-glycidyloxypropyl)trimethoxysilane as an additive. We have demonstrated that these nanofiber mats deposited on five-patterned indium tin oxide finger electrodes are excellent candidates for use as functional bioelectronic interfaces for the isolation, detection, sequential collection, and enrichment of rare CTCs through electrical activation of each single electrode. This combination behaved as an ideal model system displaying a high cell-capture yield for antibody-positive cells while resisting the adhesion of antibody-negative cells. Taking advantage of the electrochemical doping/dedoping characteristics of PEDOT:PSS materials, the captured rare cells could be electrically triggered release through the desorption phenomena of PLL-g-PEG-biotin on device surface. More than 90% of the targeted cancer cells were captured on the 3D PEDOT-based nanofiber microfluidic device; over 87% of captured cancer cells were subsequently released for collection; approximately 80% of spiked cancer cells could be collected in a 96-well plate. Therefore, this 3D PEDOT-based nanofiber approach appears to be an economical route for the large-scale preparation of systems for enhancing the downstream characterization of rare CTCs.

Manipulation of Pickering emulsion rheology using hydrophilically modified silica nanoparticles in brine

HypothesisPrevious work on Pickering emulsions has shown that bromohexadecane-in-water emulsions (50% oil) stabilized with fumed and spherical particles modified with hexadecyl groups develop a noticeable zero shear elastic storage modulus (G′0) of 200Pa and 9Pa, respectively, while in just 50mM NaCl. This high G′0 can be problematic for subsurface applications where brine salinities are higher and on the order of 600mM NaCl. High reservoir salinity coupled with low formation pressure drops could prevent an emulsion with a high G′0 from propagating deep into formation. It is hypothesized that G′0 of an emulsion can be minimized by using sterically stabilized silica nanoparticles modified with the hydrophilic silane (3-glycidyloxypropyl)trimethoxysilane (glymo). ExperimentsBromohexadecane-in-water emulsions were stabilized with low and high coverage glymo nanoparticles. Oscillatory rheology was used to monitor G′0 asa function of nanoparticle concentration, oil volume fraction, salinity, and pH. Cryogenic scanning electron microscopy was used to make observations on the emulsion microstructure. FindingsG′0 of bromohexadecane-in-water emulsions were minimized by using particles with a high coverage of glymo on the particle surface, which reduced the Ca2+/silanol site interactions. Emulsions that were stabilized with low surface coverage particles had noticeably higher G′0, however, their G′0 could be reduced by a factor of 3.3 by simply lowering the solution pH to 3. Cryo-SEM images showed that nanoparticle bridging was more pronounced with nanoparticles that had low glymo coverage as opposed to high coverage.

Synthesis of chitosan based magnetic molecularly imprinted polymers for selective separation and spectrophotometric determination of histamine in tuna fish

A novel chitosan molecularly imprinted polymers (CHI/MIPs) coated on Fe3O4 magnetic nanoparticles (MNPs) for selective solid phase extraction (SPE) of histamine (His) was synthesized by cross-linking of CHI with (3-Glycidyloxypropyl) trimethoxysilane (GPTMS) in the presence of His as the template molecule, and GPTMS/MNPS. Synthesized sorbent was characterized by scanning electron microscopy, X-ray diffraction, FT-IR and via adsorption kinetics and adsorption isotherms. The application of this sorbent was investigated in preconcentration and spectrophotometric determination of His by charge transfer complexation. The method is based on the adsorption of His on CHI/MMIPs and subsequent reaction of desorbed His with 2,3-Dichloro 5,6-dicyano-p-benzoquinone (DDQ) reagent for final spectrophotometric detection. The experimental parameters affecting separation efficiency and spectrophotometric determination were optimized. Under optimum conditions and at an analytical wavelength of 468nm, the calibration plot is linear in the 5.0–160.0ngmL−1 concentration range, and the limit of detection (estimated at S/N=3) is 1.5ngmL−1. The intra-day and inter-day precisions are in the range from 2.9 to 4.1%. The method was successfully applied for determination of His in spiked tuna fish samples where it gave recoveries ranging from 94.3 to 107.0%.

Fabrication of Biocompatible, Functional, and Transparent Hybrid Films Based on Silk Fibroin and Epoxy Silane for Biophotonics.

In this work we explored the fabrication of flexible and transparent hybrids of silk fibroin (SF) and epoxy-modified siloxane for photonic applications. It is well-known that regenerated SF solutions can form free-standing films with high transparency. Although SF has a restricted number of chemically reactive side groups, the main issues of as-cast pristine SF films regard the high solubility into aqueous media, brittleness, and low thermal stability. The design of SF films with enhanced functionality but high transparency triggers new opportunities on a broader range of applications in biophotonics. Here we present a simple, functional, yet remarkably versatile hybrid material derived from silica sol-gel process based on SF protein and (3-glycidyloxypropyl)trimethoxysilane (GPTMS), an organically modified silicon-alkoxide owning a reactive terminal epoxy group. Specifically, we investigated the effect of the addition of GPTMS into SF solutions on the processability, morphology, crystallinity, and mechanical and optical properties of the resulting hybrid films. Highly transparent (ca. 90%) and flexible free-standing hybrid films were achieved. Cell viability assays revealed that the hybrid films are noncytotoxic to rat osteoblast cells even at high GPTMS content (up to 70 wt %). The hybrid films showed enhanced thermal stability and were rich in organic (epoxy) and inorganic (silanol) functional groups according to the content of GPTMS. We also evaluated the successful preparation of high-quality optical red emissive SF hybrid films by loading YVO4:Eu3+ nanoparticles at low concentration (<5 wt %). A meaningful description of the hybrid film structure is reported from the combination of scanning electron and atomic force microscopies, vibrational spectroscopy, solid-state NMR, and X-ray diffraction analyses.

Alumina-graphene hybrid filled epoxy composite: Quantitative validation and enhanced thermal conductivity

Abstract Alumina-graphene hybrid fillers (Gr-Al2O3) were synthesized and added to the epoxy matrix to improve thermal properties of the epoxy composite. The alumina particles were surface modified with silane coupling agents like 3-Aminopropyl triethoxysilane (A-Al2O3). 3-Glycidyloxypropyl trimethoxysilane (GPTMS) was used for the surface modification of the graphene (G-Graphene). These modifications on the filler surface help to develop the interface between the fillers and the epoxy matrix, which might help to form the effective 3D thermal conductive networks. The generation of these 3D networks facilitated in reducing the Kapitza resistance and increases the transportation of phonons in the matrix, Furthermore; it improved the integral procedure decomposition temperature (IPDT) and activation energy (Ea) of the composite. Alumina-graphene hybrid filled epoxy composite (hAG-Epoxy) with 50 vol% of hybrid filler (Gr-Al2O3) expressed the considerable improvement in in-plane thermal conductivity and IPDT by ∼8.4 and ∼3.1 folds in comparison with neat epoxy, respectively. The significant improvement in thermal conductivity was related to the generation of effective 3D thermal conductive pathways formed by 2D graphene and 1D alumina in the composite.

Chitosan–silica anion exchange membrane for the vanadium redox flow energy storage battery applications

In this study, chitosan–silica anion exchange membranes were synthesized using a sol-gel process and nucleophilic substitution reaction. The basic properties of the synthesized ion exchange membranes were assessed, including water uptake, contact angle, ion exchange capacity, vanadium ion permeability, impedance, and conductivity. Furthermore, we used the chitosan–silica membranes as a separator in a single all‑vanadium redox flow battery system to investigate their charge–discharge characteristics. We then compared the performance of the chitosan–silica membranes with that of commercially available membranes in terms of impedance as a function of thickness and efficiency. In addition, we studied the relationships between the basic properties and the charge–discharge efficiency of the membranes by varying the concentration of (3-glycidyloxypropyl)trimethoxysilane (GPTMS). The results demonstrate that the mechanical strength and chemical stability of the synthesized chitosan–silica membranes were enhanced with the increase in GPTMS concentration. The chitosan–silica anion exchange membranes exhibited lower vanadium ion permeability and higher coulombic efficiency, and have a lower cost than their commercial counterparts. The highest measured coulombic efficiency reached 91%.

Electrospun Poly(γ-glutamate)/Silica Hybrids for Tissue Regeneration: Influences of Silane Coupling Agents on Chemistry, Degradation and Florescent Dye Release

Background: Electrospun hybrids consisting of poly(γ-glutamate) and silica derived from (3-glycidyloxypropyl) trimethoxysilane (GPTMS) are able to encapsulate proteins with no denaturation because of the water-based synthesis and facilitate the controlled release of encapsulated molecules into buffer solutions. We prepared new types of hybrids using (8-glycidoxyoctyl) trimethoxysilane(GOTMS) in lieu of GPTMS to examine influences of silane coupling agents on chemical structure, degradation behaviour and controlled release of molecules encapsulated in the electrospun hybrids. Methods: The calcium salt form of the polymer and GOTMS or GPTMS was mixed in water and then electrospun(polymer ratio; 48 ~ 66 wt%). Fluorescent dyes with three different molecular weights were added to the hybrid solution 0.5 h before electrospinning. The electrospun hybrids were characterised with SEM, ATR-FTIR and 29Si MAS/NMR. Degradation and molecule release behaviours of the electrospun hybrids were estimated by soaking them in buffer solutions. Results: Results of 29Si MAS/NMR demonstrated that polymer/GOTMS hybrids contained highlycondensed siloxane phases than polymer/GPTMS hybrids. Polymer/GOTMS hybrids showed a burst of Si release 12 h after soaking in buffer solutions and then stopped the release, whereas the polymer/ GPTMS hybrids showed a gradual release in the overall testing time. Some of the GOTMS in the hybrids was expected not to contribute to crosslinking between polymer chains and release from the hybrids immediately. However, the total degradation rate was smaller for the polymer/GOTMS hybrids than for the polymer/GPTMS hybrids. The polymer/GOTMS and polymer/GPTMS hybrids both exhibited molecular release with a molecular-weight dependence; however, the release rate was smaller for polymer/GOTMS than for polymer/GPTMS. Conclusion: The degradation rate and molecular release behaviour were controlled by changing the cross-linker of the hybrids from GPTMS to GOTMS. This might be because siloxane phases derived from GOTMS became more condensed and GOTMS possesses a lower hydrophilicity than GPTMS.

Polyethyleneimine modified bentonite for the adsorption of amino black 10B

The modified bentonite with a graft amount of 30% was prepared by polyethylenimine reacting with the epoxy bonds on the molecular of (3-Glycidyloxypropyl) trimethoxysilane and being grafted on the bentonite to remove amino black10B. The effects of pH, time, temperature and concentration on the adsorption capacity were studied. As the pH value increases from 3 to 10, the adsorption capacity decreased from 264.5 to 140.4mg/g. The adsorption process reached equilibrium at 90min when pH=3. The adsorption kinetics indicates that the adsorption process was very fast and in accordance with the secondary adsorption kinetics. The data about thermodynamic equilibrium was consistent with the Langmuir model. The adsorption process mainly depended on electrostatic attraction and hydrogen bonding and the adsorption data of Bent-PGLYMO-PEI showed that the maximum adsorption capacity reached 327.7mg/g.

Thiamine immobilized on silane-functionalized magnetic nanoparticles for catalytic synthesis of 2,3-dihydroquinazolin-4(1H)-ones in water

Thiamine (VB1) modified with (3-glycidyloxypropyl)trimethoxysilane (GMSI) moiety grafted onto magnetic nanoparticles (Fe3O4@SiO2@GMSI-VB1) was prepared for the first time and applied as a magnetically retrievable catalyst for an efficient and environmental friendly synthesis of 2,3-dihydroquinazolin-4(1H)-ones in aqueous media. Fe3O4@SiO2@GMSI-VB1 a have higher catalytic activity for the condensation reaction of 2-aminobenzamide and an aldehyde/ketone in aqueous medium, thus providing a novel, stable and sustainable approach to the library of 3,4-dihydroquinazolin-2(1H)-one derivatives. Various desired products have been prepared in good to excellent yields (72–95%) and selectivity with a wide range of substrates under identical conditions. The novel catalyst was characterized by FT-IR, XRD, SEM/EDX, TGA and VSM spectroscopy. In addition, the synthesized magnetic nanoparticles was recovered with the using a simple external magnet and was successfully reused for five runs without any appreciable loss of catalytic activity.