In situ pore-forming alginate hydrogel beads loaded with in situ formed nano-silver and their catalytic activity

2016 ◽  
Vol 18 (18) ◽  
pp. 12610-12615 ◽  
Author(s):  
Qin Wang ◽  
Shanshan Liu ◽  
Hong Wang ◽  
Yajiang Yang
Keyword(s):  
Catalytic Activity ◽  
Alginate Hydrogel ◽  
Nano Silver ◽  
Hydrogel Beads

Advances in Preparation and Application of Supported Nano-Silver Composites

2019 ◽  
Vol 11 (11) ◽  
pp. 1477-1488
Author(s):  
Yonghang Xu ◽  
Fangya Zhou ◽  
Tao Zhang ◽  
Limiao Lin ◽  
Jingshu Wu ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Catalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Research Progress ◽  
Nano Silver ◽  
Silver Composites ◽  
Preparation Techniques

Supported nano-silver composites, famous for large specific surface area, good dispersibility and high catalytic activity, have been widely used in chemistry and chemical engineering, biomedicine and new materials. In this paper, we report recent research progress on supported nano-silver composites as reviewed from preparation techniques (chemical reduction, physical reduction and in-situ formation), types of supporters (organic and inorganic) and anti-microbial/catalytic activity. Firstly, the principles and merits/demerits of three preparation techniques for silver nanoparticles are elaborated. Afterwards, preparation, structures and properties of supported nano-silver composites are summarized through different types of supporters, as well as their applications in catalytic reaction, pollutant control and antimicrobial. Furthermore, it has been demonstrated that silver nanoparticles produced by in-situ formation are more stable and well-distributed, readily meeting the demands for practical applications. Finally, superior supporters for nano-silver composites should be of high specific surface area and good stability, non-expensive, environmentally friendly and low-toxicity.

scholarly journals PREPARATION OF MAGNETIC HYDROGEL BY IN-SITU COPRECIPITATION PROCESS

2018 ◽  
Vol 56 (1A) ◽  
pp. 167
Author(s):  
Ngoc Uyen Nguyen
Keyword(s):  
Ammonium Hydroxide ◽  
Coprecipitation Method ◽  
Iron Ions ◽  
Alginate Hydrogel ◽  
Magnetite Nanoparticle ◽  
Hydrogel Beads ◽  
Magnetic Hydrogel ◽  
Hydrogel Matrix ◽  
Co Precipitation

This study describes a preparation of magnetite nanoparticle by co-precipitation of Fe(II) and Fe(III) in alginate hydrogel matrix. This simple process is sufficient for producing a superparamagnetic, well dispersible magnetite nanoparticle in polymer hydrogel matrix. Two approaches for iron ions loadings are induced. The first approach includes two steps, the hydrogel beads are formed before the iron ions are being diffused into the hydrogel matrix. The second approach is the simultaneous forming of hydrogel containing iron ions. The ions loaded hydrogel is then coprecipitated in the presence of ammonium hydroxide to afford iron oxide magnetite nanoparticles in alginate hydrogel matrix. The composition and characteristics of the hydrogel containing magnetite nanoparticle were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and transmission electron microscopy (TEM). The results showed that the particles size of magnetic nanoparticles prepared by in-situ coprecipitation method is around ~ 6 nm and smaller than that produced by normal coprecipitation method. The magnetic hydrogel exhibits superparamagnetic properties with the saturation magnetization of about 25 emu/g, the ratio of Mr/Ms about 0.8 ×10-3. Possessing the biocompatibility as well as superparamagnetism, the magnetite hydrogel is a promising materials for environmental and biomedical applications.

Catalytic activity of rhodium(I) complexes containing (ω-trimethylsilylalkyl)diphenylphosphines

1980 ◽  
Vol 45 (8) ◽  
pp. 2219-2223 ◽  
Author(s):  
Marie Jakoubková ◽  
Martin Čapka
Keyword(s):  
Catalytic Activity ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Electron Density ◽  
Phosphorus Atom ◽  
Proton Acceptor ◽  
Trimethylsilyl Group ◽  
Kinetics Of

Kinetics of homogenous hydrogenation of 1-heptene catalysed by rhodium(I) complexes prepared in situ from μ,μ'-dichloro-bis(cyclooctenerhodium) and phosphines of the type RP(C6H5)2 (R = -CH3, -(CH2)nSi(CH3)3; n = 1-4) have been studied. The substitution of the ligands by the trimethylsilyl group was found to increase significantly the catalytic activity of the complexes. The results are discussed in relation to the electron density on the phosphorus atom determined by 31P NMR spectroscopy and to its proton acceptor ability determined by IR spectroscopy.

On the selective aerobic oxidation of benzyl alcohol with Pd/Au-nanoparticles in batch and flow

2014 ◽  
Vol 3 (1) ◽  
pp. 99-110 ◽  
Author(s):  
Hannes Alex ◽  
Norbert Steinfeldt ◽  
Klaus Jähnisch ◽  
Matthias Bauer ◽  
Sandra Hübner
Keyword(s):  
Catalytic Activity ◽  
Benzyl Alcohol ◽  
Aerobic Oxidation ◽  
X Ray ◽  
X Ray Scattering ◽  
Oxidation Of Benzyl Alcohol ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Selective Aerobic Oxidation

AbstractNanoparticles (NP) have specific catalytic properties, which are influenced by parameters like their size, shape, or composition. Bimetallic NPs, composed of two metal elements can show an improved catalytic activity compared to the monometallic NPs. We, herein, report on the selective aerobic oxidation of benzyl alcohol catalyzed by unsupported Pd/Au and Pd NPs at atmospheric pressure. NPs of varying compositions were synthesized and characterized by UV/Vis spectroscopy, transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). The NPs were tested in the model reaction regarding their catalytic activity, stability, and recyclability in batch and continuous procedure. Additionally, in situ extended X-ray absorption fine structure (EXAFS) measurements were performed in order to get insight in the process during NP catalysis.

Construction of multilayer alginate hydrogel beads for oral delivery of probiotics cells

2017 ◽  
Vol 105 ◽  
pp. 924-930 ◽  
Author(s):  
Yang Li ◽  
Chao Feng ◽  
Jing Li ◽  
Yuzhi Mu ◽  
Ya Liu ◽  
...  
Keyword(s):  
Oral Delivery ◽  
Alginate Hydrogel ◽  
Hydrogel Beads

A facile approach to fabricate halloysite/metal nanocomposites with preformed and in situ synthesized metal nanoparticles: a comparative study of their enhanced catalytic activity

2015 ◽  
Vol 44 (19) ◽  
pp. 8906-8916 ◽  
Author(s):  
Sankar Das ◽  
Subhra Jana
Keyword(s):  
Catalytic Activity ◽  
Comparative Study ◽  
Metal Nanoparticles ◽  
Heterogeneous Catalysts ◽  
Cost Effective ◽  
Environmentally Benign ◽  
Metal Nanocomposites

Halloysite/metal nanocomposites have been synthesized through the immobilization of preformed and in situ synthesized metal nanoparticles over halloysite surfaces, which in turn produce efficient, cost-effective, and environmentally benign heterogeneous catalysts.

scholarly journals Ultra-Small Pd(0) Nanoparticles into a Designed Semisynthetic Lipase: An Efficient and Recyclable Heterogeneous Biohybrid Catalyst for the Heck Reaction under Mild Conditions

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2358 ◽  
Author(s):  
David Lopez-Tejedor ◽  
Blanca de las Rivas ◽  
Jose M. Palomo
Keyword(s):  
Catalytic Activity ◽  
Protein Structure ◽  
Heck Reaction ◽  
Catalytic Performance ◽  
Reducing Agent ◽  
Chemically Modified ◽  
Mild Conditions ◽  
In Situ Formation ◽  
Geobacillus Thermocatenulatus

A novel heterogeneous enzyme-palladium (Pd) (0) nanoparticles (PdNPs) bionanohybrid has been synthesized by an efficient, green, and straightforward methodology. A designed Geobacillus thermocatenulatus lipase (GTL) variant genetically and then chemically modified by the introduction of a tailor-made cysteine-containing complementary peptide- was used as the stabilizing and reducing agent for the in situ formation of ultra-small PdNPs nanoparticles embedded on the protein structure. This bionanohybrid was an excellent catalyst in the synthesis of trans-ethyl cinnamate by Heck reaction at 65 °C. It showed the best catalytic performance in dimethylformamide (DMF) containing 10–25% of water as a solvent but was also able to catalyze the reaction in pure DMF or with a higher amount of water as co-solvent. The recyclability and stability were excellent, maintaining more than 90% of catalytic activity after five cycles of use.

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