Green Chemistry Route Research Articles

Bio-based synthesis of silver nanoparticles from orange waste: effects of distinct biomolecule coatings on size, morphology, and antimicrobial activity.

PurposeDespite the numerous reports on biological syntheses of silver nanoparticles (AgNPs), little is known about the composition of their capping agents, protein corona of plant extract-mediated synthesis, and their influence on the properties of AgNPs. Here, orange (Citrus sinensis) waste was utilized as a source of an extract for AgNP synthesis (the protein corona composition of which was elucidated), and also as a starting material for hesperidin and nanocellulose extraction, which were used for bio-based AgNP synthesis. A comparison of the results using the two methods of synthesis is presented.MethodsAgNPs were synthesized using orange (C. sinensis) peel extract (Or-AgNPs) in a biological route, and using hesperidin (Hsd-AgNPs) and nanocellulose (extracted from oranges) in a green chemical route. Characterization of nanoparticles was carried out using zeta potential and hydrodynamic size measurements, transmission electron microscopy, and X-ray diffraction. Elucidation of proteins from protein corona was performed via ultra performance liquid chromatography-tandem mass spectrometer experiments. Antimicrobial activity was assessed via minimum inhibitory concentration assays against Xanthomonas axonopodis pv. citri (Xac), the bacterium that causes citric canker in oranges.ResultsOr-AgNPs were not completely uniform in morphology, having a size of 48.1±20.5 nm and a zeta potential of −19.0±0.4 mV. Stabilization was performed mainly by three proteins, which were identified by tandem mass spectrometry (MS/MS) experiments. Hsd-AgNPs were smaller (25.4±12.5 nm) and had uniform morphology. Nanocellulose provided a strong steric and electrostatic (−28.2±1.0 mV) stabilization to the nanoparticles. Both AgNPs presented roughly the same activity against Xac, with the minimum inhibitory concentration range between 22 and 24 μg mL−1.ConclusionDespite the fact that different capping biomolecules on AgNPs had an influence on morphology, size, and stability of AgNPs, the antibacterial activity against Xac was not sensitive to this parameter. Moreover, three proteins from the protein corona of Or-AgNPs were identified.

Facile Synthesis of Diamino-Modified Graphene/Polyaniline Semi-Interpenetrating Networks with Practical High Thermoelectric Performance.

p-Phenediamino-modified graphene (PDG) has been newly synthesized via a facile green one-step chemical route as a functionalized graphene-based additive to copolymerize with aniline for fabricating innovative PDG/polyaniline conducting polymer composites containing very special semi-interpenetrating networks (S-IPNs). The S-IPNs not only provide additional pathways by creating chemically bonded PDG and PANI for smoothly transporting carriers but greatly reduce the amount of graphene required to less than a few percent could effectively improve the overall electrical conductivity, Seebeck coefficient, and thus the thermoelectric (TE) performance. The found optimized TE figure of merit (ZT) of 0.74 approaches a practical high level which is comparable or much higher than previously reported ones for TE polymers.

Luminescent Silicon Nanocrystal embedded Sodium Silicate Glass

Green luminescent silicon nanoparticles (Si NPs), embedded in sodium silicate (SS) based glass, have been prepared by a simple green chemical synthesis route. (3-aminopropyl) triethoxysilane (APTES) was reduced by sodium ascorbate (SA) in a one-step synthesis method to prepare Si NPs. Extending the same route SS based glass was synthesised by slow evaporation of the aqueous solution of colloidal Si NPs at room temperature. Colloids of Si NPs and the SS-based glass exhibit intense room temperature greenish photoluminescence (PL) that can be detected with the naked eye. Structural investigations reveal that the Si NP sample contains dominant amorphous phase with trace amount of Si nanocrystals (NCs). Analysis of optical properties of the Si NP sample indicates that green PL is dominantly due to the contribution of oxide enriched surface states rather than quantum confinement of excitons and likewise the PL from the SS based glass is due to the presence of trace amount of Si NCs along with agglomerated amorphous oxide embedded in the glass. There is a clear indication of selective reflectance from the prepared SS based glass.

Synthesis of Some Novel Chalcone Derivative Via Microwave Method & It’s Antimicrobial Activity

Growing public awareness about the state of the environment, chemical product safety and new chemical regulatory policies is driving demand for leaders who are able to understand the science underlying environmental challenges and develop innovative solutions. Chalcones belong to the flavonoid family and display several pharmacological activities which are very important. They can be used as an initial compound for synthesis of a lot of compounds. In this research chalcone derivative are made via green chemistry route and analysed their physical and antimicrobial activity.

An Efficient Approach for the Synthesis of 1,1‐bis(2‐phenyl‐3‐indolyl)ethylene Using ZnO Nanocatalyst

A combination of nanocatalyst and green chemical route (mechanochemistry) was used to generate a series of substituted 1,1‐bis(2‐phenyl‐3‐indolyl)ethylene derivatives (4a–e) that were synthesized by reacting various 2‐arylindoles (1a–e) and acetyl chloride in absolute alcohol with or without ZnO nano as catalyst via two approaches, that is, classical and green solvent‐free route. The use of ZnO nano particles is preferred to absence of catalyst in terms of short reaction time and mild reaction conditions with reusability of the catalyst. All the synthesized compounds were characterized on the basis of their elemental and spectral data (IR, proton magnetic resonance, 13C NMR, and Mass).

Natural Honeycomb Flavone Chrysin (5,7-dihydroxyflavone)-Reduced Graphene Oxide Nanosheets Fabrication for Improved Bactericidal and Skin Regeneration

Functionalization of biocompounds on a nanomaterials surface will decrease their detrimental side effects and escape them from immunological rejection. In this study, we developed a sustainable green chemistry route to fabricate natural honeycomb flavone chrysin (5,7-dihydroxyflavone ChR)-reduced graphene oxide nanosheets (ChR-rGONSs) using a simple experimental setup. The hydroxyl (O–H) functional group of ChR wires the reduction and generation of functionalized ChR-rGONSs, and it was characterized through Raman, Fourier transform infrared (FT-IR), and X-ray photo electron (XPS) spectroscopic analyses. Effective reduction of graphene oxide (GO) into ChR-rGONSs was further revealed with X-ray diffraction (XRD), atomic force microscope (AFM), and field emission scanning electron microscopic (FE-SEM) measurements. Using the high resolution transmission electron microscopic (HR-TEM) images, zeta potential, and energy dispersive X-ray spectroscopic (EDAX) analyses, we have shown the fine morphological feature...

Optically important ZnS semiconductor nanoparticles synthesized using organic waste banana peel extract and their characterization

Zinc sulphide nanoparticles (NPs) have been synthesized first time using green chemical route of organic waste banana peels extract (BPE). The precursors Zinc Chloride (ZnCl2) and Thiourea ((NH2)2CS) of 0.01 M with various concentrations of BPE (10, 20 and 30 ml) have taken to synthesized the ZnS NPs. The prepared samples have been analyzed by optical, structural and morphological characterizations. Mixed phase of wurtzite and cubic structure are observed in the XRD pattern. Reduction in particle size from 12.50 to 9.09 nm is observed due to increase in capping strength with increasing BPE. All samples exhibit the tensile strain, while different modelling such as uniform deformation model (UDM), uniform stress deformation model (USDM) and uniform deformation energy density model (UDEDM) on XRD data have performed. The presence of tensile strain in NPs and disappearance of functional peaks in FTIR spectra is observed due to formation of new bonds with ZnS NPs. Samples exhibit strong absorption in UV region at 260–300 nm and luminescence behaviour in visible region make them suitable for various optoelectronic applications.

English

In the present study silver nanoparticles were synthesized using wild Cucumis anguria leaf extract using the green route which is a simple, cost-effective and an environmentally friendly technique. When the aqueous silver ions were exposed to the wild C. anguria leaf extract, they were reduced and this resulted in the formation of silver nanoparticles. The conditions of synthesis were optimized by adjusting the pH, time and amount of leaf extract. The synthesized silver nanoparticles were characterized by different techniques, namely ultra-violet visible spectroscopy, Fourier Transform Infrared Spectroscopy, X-ray diffraction and transmission electron microscopy. The ultra violet-visible spectrum of the synthesized silver nanoparticles shows a maximum peak at 420 nm. Fourier transform infrared spectroscopy results show the presence of alcohols, aromatics and amines suggesting the presence and binding of proteins with silver nanoparticles. Transmission electron microscopy analysis shows that the silver nanoparticles synthesized were spherical in shape with their sizes ranging between 11 and 27 nm depending on the pH conditions. X-ray diffraction analysis results show the presence of silver metal nanoparticles and their crystalline nature. The antibacterial activity of the silver nanoparticles synthesized was evaluated against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacterial and kanamycin was used as a control. The green chemistry route has proven that silver nanoparticles can be synthesized using C. anguria leaf extract in which biomolecules effectively act as reducing and capping agents.    Key words: Silver nanoparticles, green synthesis, Cucumis anguria, antibacterial activity.

Copper/copper oxide nanoparticles synthesis usingStachys lavandulifoliaand its antibacterial activity

Nanoparticles of copper/cuprous oxide (Cu/Cu 2 O) were successfully synthesised by a green chemistry route. The synthesis process was carried out using an extract of Stachys lavandulifolia as both reducing and capping agents with a facile procedure. The nanoparticles were characterised by different techniques including X-ray diffraction, indicating that the synthesised sample comprised both copper and cuprous oxide entity. The nanoparticles had a mean size of 80 nm and represented an impressive bactericidal effect on Pseudomonas aeruginosa .

Straightforward Route To Design Biorenewable Networks Based on Terpenes and Sunflower Oil

By using a combination of bio-based monomers, sunflower oil (S) and monoterperne, the β-myrcene (M), or a sesquiterpene, the β-farnesene (F), a series of novel networks SxM100–x and SxF100–x with different compositions were prepared by a green chemistry route, without any solvent or catalyst, using the Diels–Alder reaction at 100 °C to obtain branched materials. The presence of oxygen during this process is responsible of the formation of oxidation products that are characterized by Fourier transform infrared (FTIR) and Raman spectroscopies, a swell as X-ray photoelectron spectroscopy (XPS) analysis. Materials prepared with 100% terpenes (PM100 and PF100) are very hard and brittle, whereas materials prepared from vegetable oil (PS100) are tearable. The properties of SxM100–x and SxF100–x are closely linked to the composition and, in particular, to the content of terpenes. It is observed that, by increasing the proportion of terpenes from 0 to 80 wt %, there was a marked increase in the glass-transition te...

Enhanced photocatalytic activity of Ag/g-C 3 N 4 composite

Abstract Silver-graphite carbon nitride (Ag/g-C3N4) was designed and synthesized through a simple green chemical route. The photocatalyst was comprehensively characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), High-resolution transmission electron microscopy (HR-TEM), and X -ray photoelectron spectroscopy (XPS). The HR-TEM results indicate that the synthesized Ag spherical–like nanoparticles were randomly loaded on the surface of graphitic carbon nitride (g-C3N4). In addition, the Ag/g-C3N4 nanocomposites exhibited 2.5 times higher photocatalytic activity than pristine g-C3N4 for the degradation of malachite green (MG) dye under UV irradiation.

Low Temperature Synthesis and Properties of Gadolinium-Doped Cerium Oxide Nanoparticles

Gadolinium-doped cerium oxide (GDC) is an attractive ceramic material for solid oxide fuel cells (SOFCs) both as the electrolyte or in composite electrodes. The Ni/GDC cermet can be tuned as a catalytic layer, added to the conventional Ni/yttria-stabilized zirconia (YSZ), for the internal steam reforming of different fuels. Such an anode allows the SOFC to operate with hydrocarbon fuels by internal reforming. GDC exhibits high oxygen ion conductivity at a wide range of temperatures and displays a high resistance to carbon deposition. However, an inconvenience of ceria-based oxides is the high sintering temperature needed to obtain a fully dense ceramic body, which can result in undesired reactions with YSZ. In this study, a green chemistry route for the synthesis of 10 mol% GDC nanoparticles is proposed. Such a low temperature synthesis provides control over particle size and sinterability of the material. The aqueous precipitation method starts from the nitrates of both cerium and gadolinium and uses excess hexamethylenetetramine (HMT) to produce crystalline GDC at 80 ºC. As-produced powders were found to be GDC crystalline fluorite-type structure, with crystallite size ≤ 10 nm. Thermalgravimetric analysis show a small mass loss and dilatometry profiles show a total retraction of ˃ 20% up to 1400 °C. The electrical properties of the material were studied by impedance spectroscopy measurements of sintered samples in a controlled atmosphere. The samples sintered for 2 hours at 1400 °C exhibited electrical conductivity comparable to previously reported data for GDC.

Green synthesis of a nano salt and its application as multifunctional organocatalyst for Knoevenagel condensation

1,2-Ethanediammonium 3-hydroxypropane-1-sulfonate [(EDA)(HPS)] as a novel nano multifunctional organosalt was synthesized via a simple and green chemical route and characterized using various techniques such as proton nuclear magnetic resonance (1H NMR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and elemental analysis. [(EDA)(HPS)] was successfully applied as a multifunctional organocatalyst in Knoevenagel reaction of aryl/heteroaryl/alkyl aldehydes or ketones with active methylene compounds. The hydroxyl and ammonium groups in the structure of [(EDA)(HPS)] showed interesting effects on its catalytic efficiency. [(EDA)(HPS)] was also recovered and reused five times without significant decrease in activity. TEM and elemental analysis of the recovered catalyst after five reaction cycles confirmed its durability and high stability under the applied reaction conditions.

Green Chemical Routes for the Synthesis of Lead-Free Ferroelectric Material 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3

Green Chemical Routes for the Synthesis of Lead-Free Ferroelectric Material 0.5Ba(Zr_0.2Ti_0.8)O₃–0.5(Ba_0.7Ca_0.3)TiO₃

Low Temperature Synthesis and Properties of Gadolinium-Doped Cerium Oxide Nanoparticles

Gadolinium-doped cerium oxide (GDC) is an attractive ceramic material for solid oxide fuel cells (SOFCs) both as the electrolyte and in composite electrodes operating at low and intermediate temperatures. GDC exhibits high oxygen ion conductivity at a wide range of temperatures and displays a high resistance to carbon deposition when hydrocarbons are used as fuels. However, an inconvenience of ceria-based oxides is the high sintering temperature needed to obtain a fully dense ceramic body. In this study, a green chemistry route for the synthesis of 10 mol% GDC nanoparticles is proposed. The aqueous precipitation method starts from the nitrates of both cerium and gadolinium and uses excess hexamethylenetetramine (HMT) to produce crystalline GDC at 80ºC. Such a low temperature synthesis provides control over particle size and sinterability of the material at low temperatures.

Synthesis, Characterization and the Solvent Effects on Interfacial Phenomena of Jatropha Curcas Oil Based Non-Isocyanate Polyurethane.

Non-isocyanate polyurethane (NIPU) was prepared from Jatropha curcas oil (JCO) and its alkyd resin via curing with different diamines. The isocyanate-free approach is a green chemistry route, wherein carbon dioxide conversion plays a major role in NIPU preparation. Catalytic carbon dioxide fixation can be achieved through carbonation of epoxidized derivatives of JCO. In this study, 1,3-diaminopropane (DM) and isophorone diamine (IPDA) were used as curing agents separately. Cyclic carbonate conversion was catalyzed by tetrabutylammonium bromide. After epoxy conversion, carbonated JCO (CJCO) and carbonated alkyd resin (CC-AR) with carbonate contents of 24.9 and 20.2 wt %, respectively, were obtained. The molecular weight of CJCO and CC-AR were determined by gel permeation chromatography. JCO carbonates were cured with different amine contents. CJCO was blended with different weight ratios of CC-AR to improve its characteristics. The cured NIPU film was characterized by spectroscopic techniques, differential scanning calorimetry, and a universal testing machine. Field emission scanning electron microscopy was used to analyze the morphology of the NIPU film before and after solvent treatment. The solvent effects on the NIPU film interfacial surface were investigated with water, 30% ethanol, methyl ethyl ketone, 10% HCl, 10% NaCl, and 5% NaOH. NIPU based on CCJO and CC-AR (ratio of 1:3) with IPDA crosslink exhibits high glass transition temperature (44 °C), better solvent and chemical resistance, and Young’s modulus (680 MPa) compared with the blend crosslinked with DM. Thus, this study showed that the presence of CC-AR in CJCO-based NIPU can improve the thermomechanical and chemical resistance performance of the NIPU film via a green technology approach.

Green synthesis, characterization and antibacterial efficacy of palladium nanoparticles synthesized using Filicium decipiens leaf extract

Synthesis of metal nanoparticles through green chemistry route is an emerging eco-friendly approach in the present days. An eco-friendly, biogenic synthesis of palladium nanoparticles (PdNPs) using Filicium decipiens leaf extract was reported in the present study. The synthesized PdNPs were characterized by UV–visible spectroscopy, Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The PdNPs formation was confirmed by UV–visible spectrophotometer and spherical shaped PdNPs with size range of 2–22 nm was observed in TEM analysis. Energy dispersive X-ray spectroscopy (EDS) analysis confirmed the presence of palladium in the synthesized nanoparticles. The crystalline nature of PdNPs was confirmed by XRD pattern and compared with the standard. The phytochemicals and proteins were identified by their functional groups in FT-IR spectrum and revealed the amide, amine groups present in F. decipiens may have involved in the bio-reduction reaction for PdNPs synthesis. Prepared PdNPs showed potential antibacterial activity against both Gram-positive and Gram-negative bacteria. F. decipiens leaf extract based PdNPs showed high bactericidal activity against Escherichia coli, Pseudomonas aeruginosa as compared to Staphylococcus aureus and Bacillus subtilis Results showed that phytochemicals rich F. decipiens leaf extract may be utilized as an effective non-toxic reducing agent for PdNPs synthesis and prepared PdNPs may useful in biomedical applications.

One-step microwave preparation of a Mn3O4 nanoparticles/exfoliated graphite composite as superior anode materials for Li-ion batteries

The fabrication of exfoliated graphite (EG) is highly polluting due to the discharge of large amount of manganese-contained wastewater. Here, a facile and green chemistry route is developed to prepare a Mn3O4 nanoparticles (NPs)/EG composite by artfully tuning the traditional fabrication process of EG. During this treatment, Mn3O4-NPs with high crystallinity and uniform dimension of ∼7nm are found to be homogeneously and firmly anchored on the surface of EG. The composite as an anode material of Li-ion batteries exhibits favorable electrochemical performances, such as decay-free charge capacity of 655mAhg−1 extending to 120 cycles and excellent rate capability.

Microwave Synthesis of Chitosan Capped Silver-Dysprosium Bimetallic Nanoparticles: A Potential Nanotheranosis Device.

Accurate imaging of the structural and functional state of biological targets is a critical task. To amend paucities associated with individual imaging, there is high interest to develop a multifunctional theranostic devices for cancer diagnosis and therapy. Herein, chitosan coated silver/dysprosium bimetallic nanoparticles (BNPs) were synthesized through a green chemistry route and characterization results inferred that the BNPs are crystalline, spherical, and of size ∼10 nm. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray photoelectron spectroscopy (XPS) confirm the reduced metallic states of Ag and Dy in nanoparticles. These BNPs demonstrate high emission in a second near-infrared (NIR-II, 1000-1400 nm) biological window on excitation at 808 nm. Moreover, magnetization and magnetic resonance imaging (MRI) studies perceive the inherent paramagnetic features of Dy component that displays dark T2 contrast and high relaxivity. Due to high X-ray attenuation effect, BNPs exhibit better Hounsfield unit (HU) value than the reported contrast agents. BNPs unveil good biocompatibility and also express sturdy therapeutic effect in HeLa cells when tethered with doxorubicin.

Facile biosynthesis of antimicrobial zinc oxide (ZnO) nanoflakes using leaf extract of Couroupita guianensis Aubl.

Here, we report a facile green chemistry route to synthesize zinc oxide (ZnO) nanoflakes using the leaf extract of C. guianensis Aubl. (CGLE) as a potential bioreductant. Heterocyclic active constituents present in CGLE predominantly influences the reduction and forms a complexation with ZnO nanomaterials. XRD analysis confirms the growth of hexagonal ZnO with the corresponding planes at 31.8° (100), 34.5° (002), 36.3° (101), 47.6° (102), 56.6° (110), 62.9° (103), 66.4° (002), 67.9° (112), 69.0° (201), and 76.9° (202). Further, it was also demonstrated that the fabricated ZnO was highly stable possessing negative zeta value (−20.7mV) and UV–Visible spectroscopy has shown the absorbance maxima at 367nm. Interestingly, synthesized ZnO nanomaterials exhibits an excellent bactericidal effect against human pathogens and displays very less hemoglobin release, which clearly depicts its suitability to use in diverse nanomedicinal applications.