Preparation and properties of silver nanocomposite fabrics with in situ-generated silver nano particles using red sanders powder extract as reducing agent

Small metal particles have peculiar chemical and physical properties as compared to bulk materials. They are especially important in catalysis since metal particles are common constituents of supported catalysts. The structural characterization of small particles is of primary importance for the understanding of structure-catalytic activity relationships. The shape and size of metal particles larger than approximately 5 nm in diameter can be determined by several imaging techniques. It is difficult, however, to deduce the shape of smaller metal particles. Coherent electron nanodiffraction (CEND) patterns from nano particles contain information about the particle size, shape, structure and defects etc. As part of an on-going program of STEM characterization of supported catalysts we report some preliminary results of CEND study of Ag nano particles, deposited in situ in a UHV STEM instrument, and compare the experimental results with full dynamical simulations in order to extract information about the shape of Ag nano particles.

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Development of antibacterial and UV protective cotton fabrics using plant food waste and alien invasive plant extracts as reducing agents for the in-situ synthesis of silver nanoparticles

Cellulose ◽

10.1007/s10570-021-03715-y ◽

2021 ◽

Author(s):

Nina Čuk ◽

Martin Šala ◽

Marija Gorjanc

Keyword(s):

Silver Nanoparticles ◽

Green Tea ◽

Food Waste ◽

Cotton Fabrics ◽

Reducing Agent ◽

Plant Food ◽

Japanese Knotweed ◽

Tea Leaves ◽

Green Tea Leaves

Abstract The development of cellulose-based textiles that are functionalised with silver nanoparticles (AgNP), synthesised according to a green approach, and offer protection against ultraviolet (UV) radiation and pathogenic bacteria is very important today. In the present work we demonstrate the environmentally friendly approach to obtain such textile material by AgNP synthesis directly (in-situ) on cotton fabrics, using water extracts of plant food waste (green tea leaves, avocado seed and pomegranate peel) and alien invasive plants (Japanese knotweed rhizome, goldenrod flowers and staghorn sumac fruit) as reducing agents. The extracts were analysed for their total content of phenols and flavonoids and their antioxidant activity. The synthesised AgNP on cotton were round, of different size and amount depending on the reducing agent used. The highest amount of AgNP was found for samples where Japanese knotweed rhizome extract was used as reducing agent and the lowest where extracts of goldenrod flowers and green tea leaves were used. Regardless of the reducing agent used to form AgNP, all cotton samples showed excellent protection against E. coli and S. aureus bacteria and against UV radiation with UV protection factor values above 50. The best results for UV protection even after the twelve repetitive washing cycles were found for the sample functionalized with AgNP synthesised with an extract of the Japanese knotweed rhizome. Due to the presence of AgNP on cotton, the air permeability and thermal conductivity decreased. AgNP had no effect on the change in breaking strength or elongation of fabrics. Graphic abstract

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Poly(N-isopropylacrylamide-co-methacrylic acid) microgel stabilized copper nanoparticles for catalytic reduction of nitrobenzene

Materials Science-Poland ◽

10.1515/msp-2015-0074 ◽

2015 ◽

Vol 33 (3) ◽

pp. 627-634 ◽

Cited By ~ 14

Author(s):

Zahoor H. Farooqi ◽

Zonarah Butt ◽

Robina Begum ◽

Shanza Rhauf Khan ◽

Ahsan Sharif ◽

...

Keyword(s):

Copper Nanoparticles ◽

Methacrylic Acid ◽

Catalytic Reduction ◽

Aqueous Media ◽

Activation Parameters ◽

Reducing Agent ◽

Different Temperatures ◽

Entropy Of Activation ◽

Micro Reactors

Abstract Poly(N-isopropylacrylamide-co-methacrylic acid) microgels [p(NIPAM-co-MAAc)] were synthesized by precipitation polymerization of N-isopropylacrylamide and methacrylic acid in aqueous medium. These microgels were characterized by dynamic light scattering and Fourier transform infrared spectroscopy. These microgels were used as micro-reactors for in situ synthesis of copper nanoparticles using sodium borohydride (NaBH4) as reducing agent. The hybrid microgels were used as catalysts for the reduction of nitrobenzene in aqueous media. The reaction was performed with different concentrations of catalyst and reducing agent. A linear relationship was found between apparent rate constant (kapp) and amount of catalyst. When the amount of catalyst was increased from 0.13 to 0.76 mg/mL then kapp was increased from 0.03 to 0.14 min-1. Activation parameters were also determined by performing reaction at two different temperatures. The catalytic process has been discussed in terms of energy of activation, enthalpy of activation and entropy of activation. The synthesized particles were found to be stable even after 14 weeks and showed catalytic activity for the reduction of nitrobenzene.

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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 ◽

10.3390/molecules23092358 ◽

2018 ◽

Vol 23 (9) ◽

pp. 2358 ◽

Cited By ~ 7

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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3D Measurements of Nano-Particle Transport in Complex 2.5D Micro-Models

Volume 7B: Fluids Engineering Systems and Technologies ◽

10.1115/imece2015-50635 ◽

2015 ◽

Cited By ~ 1

Author(s):

Jagannath Upadhyay ◽

Daniel S. Park ◽

Karsten E. Thompson ◽

Dimitris E. Nikitopoulos

Keyword(s):

Particle Velocity ◽

Particle Transport ◽

Three Dimensional ◽

Laser Scanning Microscopy ◽

Nano Particles ◽

Confocal Laser ◽

Nano Particle ◽

Micro Model ◽

Micro Particle Image Velocimetry

A confocal Micro-Particle Image Velocimetry (C-μPIV) technique along with associated post image processing algorithms is established to quantify three dimensional distributions of nano-particle velocity and concentration at the micro-scale (pore-scale) in 2.5D porous media designed from a Boise rock sample. In addition, an in-situ, non-destructive method for measuring the geometry of the micro-model, including its depth, is described and demonstrated. The particle experiments use 900 nm fluorescence labeled polystyrene particles at a flow rate of 10 nLmin−1 and confocal laser scanning microscopy (CLSM), while in-situ geometry measurements use regular microscope along with Rhodamine dye and a depth-to-fluorescence-intensity calibration. Image post-processing techniques include elimination of background noise and signal from adsorbed nano-particle on the inner surfaces of the micro-model. In addition, a minimization of depth of focus technique demonstrates a capability of optically thin slice allowing us to measure depth wise velocity in 2.5D micro-model. The mean planar components of the particle velocity of the steady-state flow and particle concentration distributions were measured in three dimensions. Particle velocities range from 0.01 to 122 μm s−1 and concentrations from 2.18 × 103 to 1.79 × 104 particles mm−2. Depth-wise results show that mean velocity closer to the top wall is comparatively higher than bottom walls, because of higher planar porosity and smooth pathway for the nano-particles closer to the top wall. The three dimensional micro-model geometry reconstructed from the fluorescence data can be used to conduct numerical simulations of the flow in the as-tested micro-model for future comparisons to experimental results after incorporating particle transport and particle-wall interaction models.

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Surface integrity and Flank wear response under Pure coconut oil-Al2O3 nano MQL turning of Al-7079/7wt.%-TiC in-situ metal matrix composites

Journal of Tribology ◽

10.1115/1.4051863 ◽

2021 ◽

pp. 1-21

Author(s):

Sujith S V ◽

Rahul Mulik

Keyword(s):

Metal Matrix ◽

Coconut Oil ◽

Nano Particles ◽

Cutting Fluids ◽

Matrix Composites ◽

Dry Machining ◽

Cutting Zone ◽

Cutting Zone Temperature ◽

Zone Temperature

Abstract Major cooling and lubricating properties such as conduction, convection and lubricant stability at higher temperature are improvised by the addition nano particle into metal cutting fluids. The present investigation is mainly focused into the effects of pure coconut oil (PC) based nano-fluids through minimum quantity lubrication (MQL) on oblique cutting performance of Al-7079/7wt.%-TiC in-situ reinforced metal matrix composites (MMCs). The machining performance has been evaluated under dry machining, pure coconut oil (PC)-MQL and MQL by varying 0.1 % to 0.6 vol. % nano particles into PC. The performance of nano cutting fluids were compared to dry machining and PC machining in terms of cutting forces, tool wear, cutting zone temperature, and surface roughness respectively. It has found that, compared to dry and PC-MQL machining, the performance of nano MQL machining was superior among all cutting conditions. However, above 0.4 % nano particles, the nano MQL performance was degraded drastically which leads to the substantial increment in cutting forces, tool wear, surface roughness and cutting zone temperature respectively.

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