High-throughput microrespirometric characterization of activated sludge inhibition by silver nanoparticles

2018 ◽  
Vol 4 (5) ◽  
pp. 721-730
Author(s):  
Gabriel R. Hernández-Martínez ◽  
Alejandro Zepeda ◽  
Alberto Ordaz ◽  
Luis A. Sánchez-Catzin ◽  
Zaira D. Estrada-Díaz ◽  
...  

This study present for first time the application of microrespirometric method to evaluate the effect of nanomaterial on biological process.

2015 ◽  
Vol 179 ◽  
pp. 59-77 ◽  
Author(s):  
Cornelia M. Völkle ◽  
Denis Gebauer ◽  
Helmut Cölfen

Nucleation and growth of silver nanoparticles has already been investigated with various experimental and computational tools. However, owing to inherent problems associated with the analytical characterization of nucleation processes, there is a general lack of experimental data regarding the earliest precursors and smallest Ag(0) clusters. Here, we address this problem by the application of Synthetic Boundary Crystallization Ultracentrifugation, utilizing a multiwavelength detector for the first time, complemented by a specialized titration assay. These techniques shed new light on silver nanoparticle precursors existing in the pre-nucleation regime, and the initially nucleated ensemble of nanoclusters. For the first time, we present experimental data of UV-Vis spectra for fractionated silver clusters. These allow for unsurpassed insights into the sequence of nucleation and early growth species as well as their optical properties.


2021 ◽  
Vol 11 (10) ◽  
pp. 4638
Author(s):  
Jose Luis López-Miranda ◽  
Rodrigo Esparza ◽  
Marlen Alexis González-Reyna ◽  
Beatriz Liliana España-Sánchez ◽  
Angel Ramon Hernandez-Martinez ◽  
...  

This work reports, for the first time, the synthesis of silver nanoparticles using extracts of the species of Sargassum natans and Sargassum fluitans (AgNPs-S). Their antibacterial and catalytic properties are compared with silver nanoparticles obtained by chemical synthesis (AgNPs-C). The characterization of AgNPs-S and AgNPs-C was carried out using ultraviolet–visible spectroscopy (UV–Vis), dynamic light scattering (DLS), zeta potential, a scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis. The synthesis of silver nanoparticles using Sargassum extract was optimized through varying experimental parameters, such as the type of solvent used to prepare the extract, the volume of the extract, and the pH of the system. The most efficient sample (AgNPs-S) was prepared with a water–ethanol-based extract, using a 3:1 volumetric ratio of extract: a precursor salt with the addition of 1 mL of NaOH pH = 14. The AgNPs-C were spherical in shape, with an average particle size of 11.55 nm, while the AgNPs-S were polyhedral shaped, with an average particle size of 26.39 nm. The synthesized AgNPs-S were found to have significantly higher catalytic activity for the degradation of methylene blue and more effective antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa than AgNPs-C.


2016 ◽  
Vol 4 (5) ◽  
pp. 1771-1783 ◽  
Author(s):  
Guijia Cui ◽  
Zebin Sun ◽  
Haizhen Li ◽  
Xiaoning Liu ◽  
Yan Liu ◽  
...  

In this study, magnetic elongated hollow mesoporous silica nanocapsules (MSNCs) with center-radial pore channels were successfully fabricated for the first time by using the surfactant-template synthesis approach.


2019 ◽  
Author(s):  
Erick Nyakundi Ondari ◽  
Samuel Gichaba Omwenga ◽  
Nalini Madanagopal

Abstract Our previous findings showed that amines from Tridax procumbens (Family: Asteraceae) were responsible for the synthesis of silver nanoparticles. T. procumbens is a weed plant with rich source of medicinal compounds. In the current work, we studied the initial characterization of bioactive compounds by LC-MS, an essential tool for the characterization and identification of low molecular compounds. Further the isolated compound was investigated for silver nanoparticle synthesis. The leaf extracts examined revealed many novel amine derivative compounds reported for the first time mainly belonging to the group of free amines: n-Pentylhydrazine hydrochloride, 2-Nitrobenzenesulfonyl chloride, 1,7-Dichlorooctamethyltetrasiloxane, 5-Chloro-1,2,4-trihydroxybenzene, 3-Chloro-2-hydroxy-5-(trifluoromethyl)pyridine and 2-(Diphenylphosphino) ethyltriethoxysilane and conjugated amines: 5-Methoxy-diisopropyltryptamine, 4-Chlorophenoxyacetic acid, Diphenhydramine, Erucamide, n(4-((2-(2,5-dimethoxybenzylidene)hydrazino)carbonyl)ph)-4-me-benzenesulfonamide and 1,3,5-Trithia-2,4,6-tristannacyclohexane, 2,2,4,4,6,6-hexamethyl. Characterization by UV-Vis spectra, XRD, EDX and TEM revealed well separated spherical shaped AgNPs size ranging 8-50 nm. These findings suggest that further work could be extended to isolate and elucidate the structures of the identified molecules using powerful instruments such as HPLC-MS, HPLC-NMR and high resolution-MS (HR-MS). Further biotechnological approaches towards synthesis of novel metals will be enhanced to promote green chemistry technology adoption for the synthesis of nanoparticles.


Nanoscale ◽  
2012 ◽  
Vol 4 (2) ◽  
pp. 380-385 ◽  
Author(s):  
Tao Huang ◽  
Wei Cao ◽  
Hani E. Elsayed-Ali ◽  
Xiao-Hong Nancy Xu

Tick-borne encephalitis virus (TBEV) was isolated for the first time in Sweden in 1958 (from ticks and from 1 tick-borne encephalitis [TBE] patient).1 In 2003, Haglund and colleagues reported the isolation and antigenic and genetic characterization of 14 TBEV strains from Swedish patients (samples collected 1991–1994).2 The first serum sample, from which TBEV was isolated, was obtained 2–10 days after onset of disease and found to be negative for anti-TBEV immunoglobulin M (IgM) by enzyme-linked immunosorbent assay (ELISA), whereas TBEV-specific IgM (and TBEV-specific immunoglobulin G/cerebrospinal fluid [IgG/CSF] activity) was demonstrated in later serum samples taken during the second phase of the disease.


2019 ◽  
Vol 29 (3) ◽  
Author(s):  
Mai Ngọc Tuan Anh

Silver nanoplates (SNPs) having different size were synthesized by a seed-mediated method. The seeds -silver nanoparticles with 4 – 6 nm diameters were synthesized first by reducing silver nitrate with sodium borohydride in the present of Trisodium Citrate and Hydrogen peroxide. Then these seeds were developed by continue reducing Ag\(^+\) ions with various amount of L-Ascorbic acid to form SNPs. Our analysis showed that the concentratrion of L-Ascorbic acid, a secondary reducing agent, played an important role to form SNPs. In addition, the size and in-plane dipole plasmon resonance wavelenght of silver nanoplates were increased when the concentration of added silver nitrate increased. The characterization of SNPs were studied by UV-Vis, FE-SEM, EDS and TEM methods.


Author(s):  
Alfred Ludwig ◽  
Mona Nowak ◽  
Swati Kumari ◽  
Helge S. Stein ◽  
Ramona Gutkowski ◽  
...  

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