scholarly journals Synthesis, characterization and adsorption properties of nanostructured hybrid materials modified by boron and zirconium

2012 ◽  
Vol 10 (5) ◽  
pp. 1484-1494 ◽  
Author(s):  
Ralitsa Georgieva ◽  
Paunka Vassileva ◽  
Albena Detcheva ◽  
Dimitrinka Voykova ◽  
Tsvetelina Gerganova ◽  
...  

AbstractThe adsorption properties of two new nanostructured hybrid materials containing B2O3 and ZrO2 were studied. The new organic-inorganic materials were synthesized via a sol-gel method. As a modifying agent, a quantity of 10 wt.% Zr(OPr)4 or B(OCH3)3 was added. The structure of the hybrid materials was investigated by means of (Fourier transform infrared spectroscopy (FTIR), x-ray diffractometry (XRD), scanning electron microscopy (SEM), (atomic force microscopy (AFM) and nuclear magnetic resonance spectroscopy (NMR). Based on the obtained data, the most probable cross-linking mechanism for the derived gels was proposed. The characterization of texture parameters of both materials was carried out with the use of low-temperature adsorption of nitrogen. Adsorption of Cu(II), Fe(III), Cr(III), Cd(II) and Pb(II) ions on both materials was investigated using multi-component solutions with different concentrations and acidity by means of the batch method. Kinetics of adsorption was also investigated. Pseudo-first order, pseudo-second order and intraparticle diffusion models were used to analyze kinetic data. The adsorption was significantly affected by the pH value. Equilibrium data were fitted to linear Langmuir, Freundlich and Dubinin-Radushkevich models and maximum adsorption capacities were calculated.

2011 ◽  
Vol 9 (5) ◽  
pp. 932-940 ◽  
Author(s):  
Albena Detcheva ◽  
Paunka Vassileva ◽  
Ralitsa Georgieva ◽  
Dimitrinka Voykova ◽  
Tsvetelina Gerganova ◽  
...  

AbstractIn the present work the adsorption of some transition metal ions from aqueous solutions on a silica-based nanostructured hybrid material modified by aluminium was investigated. The novel organic-inorganic material was synthesized via a sol-gel method through hydrolysis and co-condensation reactions. Its structure was characterized by means of SEM, XRD and FTIR. Based on the data obtained the most probable cross-linking mechanism for the derived xerogel was proposed. The characterization of its texture parameters was carried out by low-temperature adsorption of nitrogen. The adsorption properties of this material with respect to Cu(II), Cr(III) and Pb(II) ions from single-component aqueous solutions and multi-component aqueous solutions containing also Cd(II) and Fe(III) were evaluated. The effect of contact time, acidity of initial solutions and metal ion concentrations was investigated using the batch method. Pseudo-first order, pseudo-second order and intraparticle diffusion models were used to analyze kinetic data. In all cases the adsorption was significantly affected by the pH value. Equilibrium modelling data were fitted to linear Langmuir, Freundlich and Dubinin-Radushkevich models. Best fit was observed for Langmuir model, which showed determination coefficients greater than 0.992 for all ions studied. The maximum adsorption capacities for single- and multi-component adsorption were calculated.


2008 ◽  
Vol 55-57 ◽  
pp. 749-752
Author(s):  
A. Buasri ◽  
K. Liangraksa ◽  
T. Sirisom ◽  
N. Tangkachalakul

Hybrid organic-inorganic materials were fabricated using sol-gel technique using poly(methyl methacrylate) and methacrylic acid 3-(trimethoxysilyl)propyl ester (MAMSE) with 90/10, 80/20 and 70/30 (%w/w) ratios with tetrahydrofuran (THF) solvent. The thin films were then characterized using FTIR spectra, SEM, DSC and TGA thermograms. From the preliminary characterization, the hybrid material was found to have nano and ultra scale tight pore ranges. FT-IR spectroscopy uncovered all the signature peaks characteristic of silicate structures in the near-surface regions. Fingerprints of Si-O-Si groups in cyclic and linear molecular substructures are present. The SEM image clearly shows that hybrid materials have homogenous and smooth surface. DSC analysis of the material shows interesting phenomenon regarding glass transition temperature (Tg). The hybrid material was found to have higher Tg than pure PMMA. From TGA analysis, the hybrid materials were observed to have higher thermal stability than pure PMMA.


2015 ◽  
Vol 80 (8) ◽  
pp. 1061-1071 ◽  
Author(s):  
Canan Kizilkaya ◽  
Merve Bicen ◽  
Sevim Karatas ◽  
Atilla Gungor

In this work, the effect of two different diamine monomers, containing phosphine oxide, on thermal, mechanical and morphological properties of copolyimides and their hybrid materials was investigated. Gas separation properties of the synthesized copolyimides were also analysed. Two different diamine monomers with phosphine oxide were bis(3-aminophenyl) phenylphosphine oxide (BAPPO) and bis(3-aminophenoxy-4-phenyl) phenylphosphine oxide (m-BAPPO). In the synthesis of copolyimides 3,3?-diamino-diphenyl sulfone (DDS) was also used as the diamine, as well as 2,2?-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA). Copolyimide films were prepared by thermal imidization. Hybrid materials containing 5 % SiO2 were synthesised further by sol-gel technique. The Fourier-transform infrared spectroscopy (FTIR), Nuclear magnetic resonance spectroscopy (NMR) confirmed the expected structure. Dynamic mechanical analysis (DMA) demonstrated that m-BAPPO based copolyimides had lower glass transition temperatures (Tg) than BAPPO based copolyimides. m-BAPPO containing copolyimide without silica shifted the thermal decomposition temperature to a higher value. The moduli and strength values of BAPPO diamine containing copolyimide and its hybrid were higher than those of m-BAPPO containing materials. The contact angle measurements showed the hydrophobicity. Scanning electron microscope (SEM) analysis exhibited the silica particles dispersion in the copolyimides. These copolyimides may be used in the coating industry. The CO2 permeability and the permselectivity were the highest among the other values in this study, when m-BAPPO containing copolyimide in the absence of silica was used. The gas permeabilities obtained from this work were in this decreasing order: PCO2 > PO2 > PN2.


2004 ◽  
Vol 847 ◽  
Author(s):  
Lucía Téllez ◽  
Juan Rubio ◽  
Miguel A. Valenzuela ◽  
Fausto Rubio ◽  
Ernesto Morales ◽  
...  

ABSTRACTPorous SiO2-PDMS-TiO2 hybrid materials have been prepared by the Sol-Gel method using tetraethoxysilane (TEOS), silanol terminated-Polydimethylsiloxane (PDMS) and tetrabuthylortotitanate (TBT) as precursors. These materials were characterized by means of nitrogen adsorption, mercury porosimetry and helium picnometry. It was found that the meso and microporosity are predominant in all samples. The influence of the TBT concentration in the final pore structure and texture of SiO2-PDMS-TiO2 hybrid materials was studied. Results showed that increasing the TBT concentration decreases the pore volume of micropores, mesopores and macropores. On the other hand the specific surface areas of meso and macropores decreases with increasing TBT content, but micropore areas increase with TBT. These results are assigned to the formation of ultramicropores when TBT is added. In addition, surface roughness is found to increase with TBT concentration which is attributed to the formation of hydrous titanium oxide based nanoparticles.


MRS Bulletin ◽  
2001 ◽  
Vol 26 (5) ◽  
pp. 402-408 ◽  
Author(s):  
Barry Arkles

Sol-gel processing readily yields both inorganic and hybrid organic–inorganic materials. Commercial applications of solgel technology preceded the formal recognition of this technology as an important field of study. Likewise, successful commercial hybrid organic–inorganic polymers have been part of manufacturing technology since the 1950s.


2013 ◽  
Vol 726-731 ◽  
pp. 2687-2690
Author(s):  
Qian Cheng ◽  
Xing Yong Liu ◽  
Min Li

With the development of the biogas construction, a plenty of biogas slurry was generated. It brought destruction to the environment for the biogas slurry was rich in nutrient components, especially ammonia-nitrogen. Its important that biogas slurry should be treated before it returns to the environment. The zeolite is extensively used in ammonia-nitrogen adsorption for its good adsorption effect. In this study, a modified coal fly ash (CFA) which was produced from raw CFA and had similar structure with zeolite was used as the adsorbent to adsorb ammonia-nitrogen in biogas slurry. The optimum adsorption conditions of modified CAF on adsorbing ammonia-nitrogen in biogas slurry were explored. The results showed that the best conditions were: the mass of modified CAF 1.3g, the initial pH value of solution 5~7 and the adsorption time 20 min.


2000 ◽  
Vol 628 ◽  
Author(s):  
Guang-Way Jang ◽  
Ren-Jye Wu ◽  
Yuung-Ching Sheen ◽  
Ya-Hui Lin ◽  
Chi-Jung Chang

This work successfully prepared an UV curable organic-inorganic hybrid material consisting of organic modified colloidal silica. Applications of UV curable organic-inorganic hybrid materials include abrasion resistant coatings, photo-patternable thin films and waveguides. Colloidal silica containing reactive functional groups were also prepared by reacting organic silane and tetraethyl orthosilicate (TEOS) using sol-gel process. In addition, the efficiency of grafting organic moiety onto silica nanoparticles was investigated by applying TGA and FTIR techniques. Experimental results indicated a strong interdependence between surface modification efficiency and solution pH. Acrylate-SiO2 hybrid formation could result in a shifting of thermal degradation temperature of organic component from about 200°C to near 400°C. In addition, the stability of organic modified colloidal silica in UV curable formula and the physical properties of resulting coatings were discussed. Furthermore, the morphology of organic modified colloidal silica was investigated by performing TEM and SEM studies‥


2020 ◽  
Vol 3 (3) ◽  
Author(s):  
Jothi M ◽  
Sowmiya K

Nickel Oxide (NiO) is an important transition metal oxide with cubic lattice structure. NiO is thermally stable that is suitable for tremendous applications in the field of optic, ceramic,glass, electro-chromic coatings, plastics, textiles, nanowires, nanofibers, electronics,energy technology, bio-medicine, magnetism and so on. In this present study, NiO nanoparticles were successfully synthesized by sol-gel technique. Nano-sols were prepared by dissolving Nickel-Chloride [NiCl2.6H2O] in NaOH solvent and were converted into nano structured gel on precipitation. A systematic change in preparation parameters like calcination temperature, time, pH value has been noticed in order to predict the influence on crystallite size. Then the prepared samples were characterized by the X-ray Diffraction Spectroscopic (XRD), UV-VIS Spectroscopy, Fourier Transform Infra-Red Spectroscopy (FTIR), Energy Dispersive X-ray Spectroscopy (EDX), Scanning Electron Microscopy (SEM) and Particle Size Analyzer (PSA). From XRD, the average crystalline-size has been calculated by Debye-Scherrer Equation and it was found to be 12.17 nm and the band gap energy of Nickel oxide (NiO) from UV studies reveals around 3.85 eV. Further, EDX and FTIR studies, confirm the presences of NiO nanoparticles. The SEM study exhibits the spherical like morphology of Nickel oxide (NiO). Further from PSA, the mean value of NiO nanoparticles has been determined.


2016 ◽  
pp. 565-570
Author(s):  
Huang Qin ◽  
Zhu Si-ming ◽  
Zeng Di ◽  
Yu Shu-juan

Sugar beet pulp (SBP) was used as low value adsorbent for the removal of calcium from hard water. Batch experiments were conducted to determine the factors affecting adsorption of the process such as pH value and Ca concentration. The adsorption equilibrium of Ca2+ by the SBP is reached after 100min and a pseudo second-order kinetic model can describe the adsorption process. The initial concentrations of Ca varied from 927 to 1127mgCa2+/L. A dose of 30g/L sugar beet pulp was sufficient for the optimum removal of calcium. The overall uptake of Ca ions by sugar beet pulp has its maximum at pH=8. The adsorption equilibrium data fitted well with the Langmuir adsorption isotherm equation.


2000 ◽  
Vol 42 (7-8) ◽  
pp. 283-290 ◽  
Author(s):  
H.-C. Tsai ◽  
R.-A. Doong

A sol-gel based fiber-optic biosensor with acetylcholinesterase as the biorecognition element has been developed for the rapid determination of organophosphorus pesticides. Nine fluorescent indicators, acridine, acridine orange, neutral red, DAPI, rhodamine B, fluorescein, umbelliferone, FITC on celite and FITC-dextran, have been examined to optimize the fiber-optic system. Results showed that acridine and FITCs were sensitive to the change of pH value caused by the enzyme-substrate catalysis reaction. However, the sensitivity of acridine was 260 times lower than that of FITCs. Higher toxicity of acridine to acetylcholinesterase than FITC was also observed. Moreover, the high-molecular-weight FITC-dextran showed low leakage rate when immobilizing using sol-gel technology, showing that the FITC-dextran was a suitable pH sensitive fluorescent indicator for the OPPs biosensor. The response of the fiber-optic biosensor to the substrate, acetylcholine, was highly reproducible (RSD=3.5%). A good linearity of acetylcholine in the range from 0.5 to 20 mM was also obtained (R2=0.98). Furthermore, a 30% inhibition can be achieved in 30min when 152 ppb paraoxon was added into the system. The results show the possibility for real-time determination of organophosphorus pesticides by using the biosensor developed in this study.


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