Showing papers on "Silica gel published in 2015"
TL;DR: In this paper, the structure and morphology of the synthesized biogenic nanoparticles were analyzed using transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectra showed O-Si-O stretching vibrations between 1056 and 1078 cm −1.
142 citations
TL;DR: In this paper, the authors optimized the amount of diglycolic anhydride used for the synthesis of the adsorbent and evaluated the utility of the adorbent in terms of its selectivity for rare earth metal ions, the rate of metal ion adsorption, and the desorption behavior of the ions.
141 citations
TL;DR: Composite aerogels based on interpenetrated cellulose-silica networks were prepared and characterised and revealed an almost threefold increase in pores specific surface area, from cellulose aerogel alone to organic-inorganic composite.
130 citations
TL;DR: In this paper, the authors used 29Si NMR and 27Al NMR spectroscopy with XRD to investigate the degraded layer on hardened cement paste exposed to HCl and H2SO4.
125 citations
TL;DR: A bifunctional ammonium salt covalently bound to a polystyrene or silica support proved to be an efficient and recyclable catalyst for the solvent-free synthesis of cyclic carbonates from epoxides and CO2.
Abstract: A bifunctional ammonium salt covalently bound to a polystyrene or silica support proved to be an efficient and recyclable catalyst for the solvent-free synthesis of cyclic carbonates from epoxides and CO2. The catalyst can be easily recovered by simple filtration after the reaction and reused in up to 13 consecutive runs with retention of high activity and selectivity even at 90 °C. The scope and limitations of the reaction has been evaluated in terms of reaction conditions and substrate scope.
108 citations
TL;DR: In this article, the effects of the weight ratios of Gel to MCM-41, amine loadings, adsorption temperatures, and CO 2 partial pressures at different temperatures were investigated in a self-assembled fixed bed reactor.
90 citations
TL;DR: In this paper, different zeolite-like powders (SAPO34 and FAPO-34) coated aluminum sheets were fabricated and their performance was tested and analyzed to investigate the feasibility in a DCHE system.
80 citations
TL;DR: In this paper, different silica gel-LiCl composite desiccant coated aluminum sheets were fabricated and some key parameters were studied, which indicated that composite sheets exhibited higher dynamic sorption quantities and faster sorption rates.
Abstract: Desiccant coated aluminum-fin is an important part in desiccant coated heat exchanger (DCHE). It will affect the overall performance of this novel solid desiccant component. In the paper, different silica gel-LiCl composite desiccant coated aluminum sheets were fabricated and some key parameters were studied. Nitrogen adsorption suggested that texture properties of composite desiccants were different from silica gel due to impregnated salt and combined action of silica sol and silica gel. The highest thermal conductivity of composite sheets was 5.8 Wm−1K−1, which is twice of silica gel coated one. Sorption kinetics indicated that composite sheets exhibited higher dynamic sorption quantities and faster sorption rates. Sorption isotherms were also obtained and fitted with Dubinin–Astakhov equation. Besides, dehumidification capacity of composite DCHE was tested and compared with silica gel one. Results indicated that enhanced dehumidification capacity can be achieved with use of composite desiccant in the DCHE system.
76 citations
TL;DR: In this article, composite desiccant based on silica gel and lithium chloride is adopted as solid adsorbent in DCHE, and the equilibrium isotherms of aluminum foils were obtained and analyzed through experiment.
74 citations
TL;DR: In this article, two nonporous metallic mesh arrangements having high thermal conductivity compared to silica sand and silica gel were used as a packing material in a fixed bed setup for faster hydrate growth kinetics.
74 citations
TL;DR: In this paper, the authors presented adsorption cooling systems with silica gel and activated carbon as adsorbents, which are powered by low grade heat sources, and the previous experimental and numerical models are discussed.
Abstract: This study presents adsorption cooling systems with silica gel and activated carbon as adsorbents. Adsorption cooling systems powered by low grade heat sources are presented here. Moreover, the previous experimental and numerical models are discussed. The study revealed that the performances of silica gel and activated carbon based adsorption cooling systems are still low and hence these systems are in the stage of demonstration and prototyping. It was concluded that there is still an opportunity for adopting more modern solar energy collecting and transferring technologies, and more advanced design optimization and simulation models. However, heat recovery, mass recovery, multi-bed and multi-stage technologies are promising technologies in improving the COP and SCP of these systems.
TL;DR: In this paper, the authors present the thermodynamic frameworks to describe the dynamic uptakes of water vapor on various sizes and layers of silica gels for adsorption cooling applications.
TL;DR: Li et al. as discussed by the authors developed a new type of consolidated composite sorbent by using activated carbon (AC) as a porous host matrix to carry LiCl, mixing with expanded natural graphite treated with sulfuric acid (ENG-TSA) to increase heat transfer and adding silica solution (SS) as binder to enhance mechanical strength.
TL;DR: In this article, a very fast (less than 2 h) and one-pot synthetic strategy was developed for the synthesis of silica aerogels, which showed a great potential to synthesize silica aerosol in the industrial scale.
TL;DR: In this paper, a renewable β-cyclodextrin (β-CD) was grafted onto the surface of silica gel using (3-chloropropyl)trimethoxysilane and ethylenediamine as linking groups to construct adsorbent in water treatment (CD@Si).
TL;DR: In this article, porous silica gel-solid beads have been made from economically affordable water-glass precursors via sol-gel nano casting technique, and they were impregnated with 3-aminopropyltrimethoxysilane (APTMS) and polyethylenimine (PEI) active functional groups at different percentages.
TL;DR: Scaffolds containing silicon dioxide for tissue engineering may enhance cell growth through ERK1/2 activation only when NPs around 50–120 nm in size are included, and single component silica-derived NPs could be useful for bioscaffolds in stem cell therapy.
Abstract: Background Silicon dioxide composites have been found to enhance the mechanical properties of scaffolds and to support growth of human adipose tissue-derived stem cells (hADSCs) both in vitro and in vivo. Silica (silicon dioxide alone) exists as differently sized particles when suspended in culture medium, but it is not clear whether particle size influences the beneficial effect of silicon dioxide on hADSCs. In this study, we examined the effect of different sized particles on growth and mitogen-activated protein kinase signaling in hADSCs. Methods Silica gel was prepared by a chemical reaction using hydrochloric acid and sodium silicate, washed, sterilized, and suspended in serum-free culture medium for 48 hours, and then sequentially filtered through a 0.22 μm filter (filtrate containing nanoparticles smaller than 220 nm; silica NPs). hADSCs were incubated with silica NPs or 3 μm silica microparticles (MPs), examined by transmission electron microscopy, and assayed for cell proliferation, apoptosis, and mitogen-activated protein kinase signaling. Results Eighty-nine percent of the silica NPs were around 50-120 nm in size. When hADSCs were treated with the study particles, silica NPs were observed in endocytosed vacuoles in the cytosol of hADSCs, but silica MPs showed no cell entry. Silica NPs increased the proliferation of hADSCs, but silica MPs had no significant effect in this regard. Instead, silica MPs induced slight apoptosis. Silica NPs increased phosphorylation of extracellular signal-related kinase (ERK)1/2, while silica MPs increased phosphorylation of p38. Silica NPs had no effect on phosphorylation of Janus kinase or p38. Pretreatment with PD98059, a MEK inhibitor, prevented the ERK1/2 phosphorylation and proliferation induced by silica NPs. Conclusion Scaffolds containing silicon dioxide for tissue engineering may enhance cell growth through ERK1/2 activation only when NPs around 50-120 nm in size are included, and single component silica-derived NPs could be useful for bioscaffolds in stem cell therapy.
TL;DR: The performance analysis revealed that SiO2MIP displayed better affinity to the three investigated isoflavones compared with SiO1NIP, and indicated the structural differences between imprinted and non-imprinted polymers.
TL;DR: In this article, a heterogeneous acid catalyst, silica sulfuric acid, was prepared from silica gel (SiO2) and sulfic acid (H2SO4) adding SO3H functional group to SiO2 has been confirmed through various characterization techniques.
TL;DR: In this paper, a green methodology for the direct amidation of carboxylic acids with amines using silica gel as a solid support and catalyst is described, which is exemplified by the use of several aliphatic, aromatic, unsaturated and fatty acids.
TL;DR: A novel purification process for the enrichment of sc-SWCNTs that combines selective conjugated polymer extraction (CPE) with selective adsorption using silica gel, termed hybrid-CPE (h- CPE), has been developed, providing a high purity sc- SWCNT material with a significant improvement in process efficiency and yield.
Abstract: A novel purification process for the enrichment of sc-SWCNTs that combines selective conjugated polymer extraction (CPE) with selective adsorption using silica gel, termed hybrid-CPE (h-CPE), has been developed, providing a high purity sc-SWCNT material with a significant improvement in process efficiency and yield. Using the h-CPE protocol, a greater than 5 fold improvement in yield can be obtained compared to traditional CPE while obtaining sc-SWCNT with a purity >99.9% as assessed by absorption spectroscopy and Raman mapping. Thin film transistor devices using the h-CPE derived sc-SWCNTs as the semiconductor possess mobility values ranging from 10–30 cm2 V−1 s−1 and current ON/OFF ratio of 104–105 for channel lengths between 2.5 and 20 μm.
TL;DR: In this paper, a CNC-based composite film with 40% hydrophobic binder was used as a solid electrolyte for alkaline fuel cells, and the film with 60% CNC and 40% binder is characterized by the lowest hydroxide conductivity normalized swelling ratio.
Abstract: Cellulose nanocrystal (CNC)-based composite films were prepared as a solid electrolyte for alkaline fuel cells. Poly(vinyl alcohol) (PVA) and silica gel hybrid were used to bind the CNCs to form a robust composite film. The mass ratio (i.e., 1 : 1, 1 : 2) of PVA and silica gel was tuned to control the hydrophobicity of the resulting films. Composite films with a range of CNC contents (i.e., 20–60%) were prepared to demonstrate the impact of CNCs on the performance of these materials as a solid electrolyte for alkaline fuel cells. Different from previously reported cross-linked polymer films, CNC-based composite films with 40% hydrophobic binder (i.e., PVA : silica gel = 1 : 2) exhibited simultaneous low water swelling (e.g., ∼5%) and high water uptake (e.g., ∼80%) due to the hydrophilicity and extraordinary dimensional stability of CNCs. It also showed a conductivity of 0.044 and 0.065 S cm−1 at 20 and 60 °C, respectively. To the best of our knowledge, the film with 60% CNC and 40% binder is characterized by the lowest hydroxide conductivity-normalized swelling ratio. Decreased CNC contents (i.e., 40 and 20%) resulted in comparable hydroxide conductivity but a greater swelling ratio. These results demonstrate the advantage of CNCs as a key component for a solid electrolyte for alkaline fuel cells over conventional polymers, suggesting the great potential of CNCs in improving the dimensional stability while maintaining the conductivity of existing anion exchange membranes.
TL;DR: The properties of core–shell and silica gel monolithic columns are briefly summarized and their applications in two-dimensional separations of peptides, proteins, oligomer surfactants, fats and oils, carotenoids, phenolic and flavone compounds in plant extracts, food, and beverages are reviewed.
Abstract: The crucial point affecting the separation time in comprehensive two-dimensional liquid chromatography is the performance of the column used in the second dimension, which should allow highly efficient fast chromatographic separations in the short time available for the analysis of fractions transferred from the first to the second dimension (often 1 min or less) This can be accomplished on short columns packed with sub-2-μm particles, at the cost of very high operation pressure Core-shell or silica monolithic columns have better permeability, and their use in the second dimension of comprehensive two-dimensional liquid chromatography with conventional liquid chromatography instrumentation is continuously increasing Monolithic columns based on organic polymer matrices offer a wide selection of stationary phase chemistries, including new hydrophilic interaction liquid chromatography materials, which can be used in the design of novel two-dimensional separations Some organic polymer monolithic materials offer a dual retention mechanism (reversed-phase hydrophilic interaction liquid chromatography), so a single column can be used in alternating runs for highly orthogonal off-line two-dimensional and even three-dimensional separations In the present work, the properties of core-shell and silica gel monolithic columns are briefly summarized and their applications in two-dimensional separations of peptides, proteins, oligomer surfactants, fats and oils, carotenoids, phenolic and flavone compounds in plant extracts, food, and beverages are reviewed
TL;DR: In this paper, N-(2-aminoethyl)-2,3-dihydroxybenzaldimine group (AEDHB-SG) was functionalized with silica gel and characterized by elemental analysis and FT-IR spectroscopy.
TL;DR: In this article, six kinds of different ionic liquid-modified silica were synthesized and characterized with infrared spectroscopy, thermogravimetric analysis, elemental analysis, N 2 adsorption-desorption isotherms and particle size distribution.
TL;DR: A novel mixed-mode stationary phase was synthesised starting from N-Boc-glutamine, aniline and spherical silica gel and used for HILIC separation of four nucleotides and five nucleosides and phytohormones and phenolic compounds were separated to see influence of the new stationary phase in reverse phase conditions.
TL;DR: In this article, the effect of hydrogels on calcite micro-and mesostructure in the gel/calcite composits was investigated using high-resolution microscopy and electron backscatter diffraction (EBSD).
Abstract: We investigate the effect of gelatin, agarose, and silica hydrogel with and without magnesium in the growth medium on calcite single crystal growth and aggregate formation. We characterize the hydrogel and the mineral by cryo-scanning electron microscopy (SEM), high-resolution SEM, and electron backscatter diffraction (EBSD). We image the pristine hydrogel fabric and the fabric of hydrogel incorporated into the mineral. We visualize the hydrogel–mineral interface and investigate the effect of the hydrogels on calcite micro- and mesostructure in the gel/calcite composits. We compare hydrogel fabrics in biomimetic hybrid composites with biopolymer matrices and networks in biological carbonate tissues of bivalves, gastropods, brachiopods, and corraline red algae. In Mg-free environments, silica gel has very little effect on crystal morphology and arrangement; the gel/calcite composite that forms is a single gradient mesocrystal. Agarose and gelatin hydrogels influence mineral organization in gel/calcite aggr...
TL;DR: In this article, the effects of two types of silica particles, with different characteristics of porosity, on segmental mobility of poly(dimethylsiloxane), PDMS, in core-shell nanocomposites with two contents of polymer, 40 and 80,wt%, were studied by employing thermal (DSC) and dielectric (DRS, TSDC) techniques, under different annealing procedures.
TL;DR: In this paper, the authors developed a composite material to be used in air conditioning systems by combining silica gel with both polyacrylic acid and sodium polyacrylate, and the results showed that the optimal composite material was produced at a mixing ratio of 10:1:1.
TL;DR: In this paper, an acid functionalized ionic liquid was entrapped within a silica gel to yield a recyclable liquid phase catalyst for the dehydration of rac-1-phenyl ethanol.
Abstract: An acid-functionalized ionic liquid was entrapped within a silica gel to yield a recyclable liquid phase catalyst for the dehydration of rac-1-phenyl ethanol. Hot filtration tests showed that the activity was within the gel. Comparison with an analogous Supported Ionic Liquid Phase (SILP) system revealed fundamental differences in the properties and behavior of the materials.