scholarly journals Predicting growth of gold nanoparticle by photochemical reduction process associated with mathematical modelling

2015 ◽  
Vol 11 (3) ◽  
Author(s):  
Hazidatul A. Hamlan ◽  
Norma Alias ◽  
Jia Cherng Chong ◽  
Hood Hong Ley ◽  
Noriah Bidin ◽  
...  
Keyword(s):  
Growth Rate ◽  
Gold Nanoparticles ◽  
Numerical Analysis ◽  
Iterative Method ◽  
Mathematical Modelling ◽  
Chemical Properties ◽  
Reduction Process ◽  
Photochemical Reduction ◽  
New Generation ◽  
Photocatalytic Processes

Nowadays, to develop new generation of nanodevices, most researchers such as chemists, physicists, biologists, even the engineers are focusing their studies towards the uniqueness as well as the chemical properties of metal nanoparticles. Even, the mathematician also has governed the appropriate mathematical modelling regarding of properties of nanoparticles such as gold nanoparticles. In this paper, some experiment regarding the photochemical and photocatalytic processes for predicting the growth of gold nanoparticles from previous studies has been reviewed. Besides that, in observing the growth rate of gold nanoparticles, a mathematical modelling has been governed. Where, ultraviolet, UV radiation with wavelength of 366 nm and 253.7 nm has been fixed as the constant parameters. The governing equation is then solved numerically using some iterative method known as Jacobi and Gauss Seidel. The convergence of both methods is discussed in detail and the numerical analysis is presented in table form to justify and validate the convergence as well as the performance of the proposed iterative methods.

scholarly journals Characterization of Biocompatible Gold Nanoparticles Synthesized by using Curcuma xanthorrhiza and their Catalytic Activity

2020 ◽  
Vol 16 (2) ◽  
pp. 214-225
Author(s):  
Khairiza Lubis ◽  
Nuannoi Chudapongse ◽  
Hau Van Doan ◽  
Oratai Weeranantanapan
Keyword(s):  
Electron Microscopy ◽  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Ftir Spectroscopy ◽  
Dye Degradation ◽  
Chemical Properties ◽  
Reduction Process ◽  
Industrial Applications ◽  
Biological Synthesis ◽  
Curcuma Xanthorrhiza

Background: Based on various distinguished physical and chemical properties of gold nanoparticles, they have far wide applications in several areas of industry and medicine, such as catalysis, bio-sensor and drug delivery. Compared to a chemical method, biological synthesis is an economical and less toxic process, thus it is a better alternative for nanoparticle synthesis. In this study, an environmentally friendly method was chosen to produce AuNPs using Curcuma xanthorrhiza. Methods: Alkaline aqueous extract of C. xanthorrhiza rhizomes, which acts as a reducing and stabilizing agent was used to produce AuNPs by bio-reduction of HAuCl4. The formation of AuNPs was periodically monitored by UV-visible spectroscopy. The obtained AuNPs were characterized by Xray diffraction, energy dispersive spectroscopy, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared (FTIR) spectroscopy. Catalytic activity and toxicity of the AuNPs were evaluated. Results: The AuNPs obtained from this study mostly were spherical in shape with approximately 15 nm in size. The presence of functional groups derived from C. xanthorrhiza rhizome extract involved in the gold bio-reduction process was confirmed by the spectrum of FTIR spectroscopy. The biosynthesized AuNPs at the concentration of 0.5 μg/ml had catalytic activity in dye degradation of Congo red. The results showed that this biogenic AuNPs did not cause any toxicity to zebrafish embryos and all tested cell lines. Conclusion: The biocompatible AuNPs with catalytic activity were successfully fabricated with C. xanthorrhiza rhizome extract by simple eco-friendly and inexpensive method. This catalytic activity of the obtained AuNPs is potentially useful for industrial applications as well as nanoscience and nanotechnology.

scholarly journals Green Silver and Gold Nanoparticles: Biological Synthesis Approaches and Potentials for Biomedical Applications

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 844 ◽  
Author(s):  
Andrea Rónavári ◽  
Nóra Igaz ◽  
Dóra I. Adamecz ◽  
Bettina Szerencsés ◽  
Csaba Molnar ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Biomedical Applications ◽  
Biological Activities ◽  
Large Body ◽  
Chemical Properties ◽  
Biological Synthesis ◽  
Silver And Gold Nanoparticles ◽  
Comprehensive Collection ◽  
Synthetic Approaches ◽  
Physical And Chemical

The nanomaterial industry generates gigantic quantities of metal-based nanomaterials for various technological and biomedical applications; however, concomitantly, it places a massive burden on the environment by utilizing toxic chemicals for the production process and leaving hazardous waste materials behind. Moreover, the employed, often unpleasant chemicals can affect the biocompatibility of the generated particles and severely restrict their application possibilities. On these grounds, green synthetic approaches have emerged, offering eco-friendly, sustainable, nature-derived alternative production methods, thus attenuating the ecological footprint of the nanomaterial industry. In the last decade, a plethora of biological materials has been tested to probe their suitability for nanomaterial synthesis. Although most of these approaches were successful, a large body of evidence indicates that the green material or entity used for the production would substantially define the physical and chemical properties and as a consequence, the biological activities of the obtained nanomaterials. The present review provides a comprehensive collection of the most recent green methodologies, surveys the major nanoparticle characterization techniques and screens the effects triggered by the obtained nanomaterials in various living systems to give an impression on the biomedical potential of green synthesized silver and gold nanoparticles.

Effect of Voltage on Colloidal Gold (Au) Nanoparticles Produced Using Electro-Dissolution-Reduction Method

2015 ◽  
Vol 1115 ◽  
pp. 386-389
Author(s):  
Haroon Haiza ◽  
I.I. Yaacob ◽  
Ahmad Zahirani Ahmad Azhar
Keyword(s):  
Gold Nanoparticles ◽  
Electron Microscope ◽  
Colloidal Gold ◽  
Reduction Process ◽  
Chloride Ions ◽  
Complex Ions ◽  
Dc Power ◽  
Colloidal Gold Nanoparticles ◽  
Transmission Electron ◽  
The Mean

Colloidal gold nanoparticles have been successfully prepared using a simple two-electrode cells connected to a DC power supply. During the electro-dissolution-reduction process, the bulk gold at the anode oxidized into gold cations which then reacted with the chloride ions to form aurochloride complex. The complex ions were then reduced by the citrate ion to form colloidal gold nanoparticles. The size and shape of the nanoparticles were modulated by varying the terminal voltages. The colloidal gold nanoparticles obtained were characterized by field-emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and ultraviolet-visible spectrophotometer (UV-Vis). From FESEM analysis, it was found that by increasing the voltage, the size of colloidal gold nanoparticles produced marginally decreased. The mean sizes of gold nanoparticles were roughly about 23.5 nm, 23.2 nm and 19.3 nm for 32 V, 36 V and 40 V, respectively. TEM micrograph showed that the shape of gold nanoparticles obtained is almost spherical. The characteristic peaks of UV-Vis spectra revealed that the suspension was indeed colloidal gold nanoparticles. Keywords: Gold, Nanoparticles, Electro-dissolution-reduction

Gold nanoparticle based fluorescent oligonucleotide probes for imaging and therapy in living systems

The Analyst ◽  
2019 ◽  
Vol 144 (4) ◽  
pp. 1052-1072 ◽  
Author(s):  
Yanjing Yang ◽  
Shian Zhong ◽  
Kemin Wang ◽  
Jin Huang
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Chemical Properties ◽  
Living Systems ◽  
Oligonucleotide Probes ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
And Chemical Properties

Gold nanoparticles (AuNPs) with unique physical and chemical properties have become an integral part of research in nanoscience.

scholarly journals One-pot synthesis of a new generation of hybrid bisphosphonate polyoxometalate gold nanoparticles as antibiofilm agents

2019 ◽  
Vol 1 (9) ◽  
pp. 3400-3405 ◽  
Author(s):  
S. Tomane ◽  
E. López-Maya ◽  
S. Boujday ◽  
V. Humblot ◽  
J. Marrot ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Antibiofilm Activity ◽  
Hybrid Nanomaterials ◽  
One Pot ◽  
One Pot Synthesis ◽  
Antibiofilm Agents ◽  
New Generation

A reduced polyoxovanadate functionalized with alendronate molecules was used for the synthesis of gold nanoparticles; these hybrid nanomaterials exhibit high antibiofilm activity.

Electrooxidation of Methanol on Carbon Supported Gold Nanoparticles

2013 ◽  
Vol 313-314 ◽  
pp. 232-236
Author(s):  
Dan Zhang
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Competitive Adsorption ◽  
Chemical Reduction ◽  
Reduction Process ◽  
Carbon Support ◽  
Transmission Electron ◽  
Supported Gold Nanoparticles ◽  
Supported Gold

Activated carbon supported gold nanoparticles (Au/C) were prepared by a chemical reduction process using NaBH4as a reducing agent. The characterization of transmission electron microscope indicated that the Au nanoparticles (AuNPs) in the Au/C catalyst were highly well dispersed on the carbon support. The catalytic activity of the Au/C catalyst for the methanol electrooxidation (MEO) was investigated by the cyclic voltammetry (CV). The results displayed that the Au/C catalyst exhibited a favorable catalytic activity towards the MEO in alkaline solution. Moreover, the competitive adsorption between OH-and CH3OH on the surface of the AuNPs in the Au/C catalyst existed in the course of the MEO. Based on this competitive adsorption, the mechanism of the MEO on the Au/C catalyst was further investigated.

A functional Ag-TiO2 nanocomposite solar selective absorber with antimicrobial activity by photochemical reduction process

2019 ◽  
Vol 199 ◽  
pp. 111626 ◽  
Author(s):  
M. Shiva Prasad ◽  
V.G. Vasavi Dutt ◽  
K.K. Phani Kumar ◽  
S.R. Atchuta ◽  
V. Anbazhagan ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Reduction Process ◽  
Photochemical Reduction

scholarly journals Innovation, Mark-Up and Firm Growth: Evidence from China’s New Generation IT Industry

2019 ◽  
Vol 11 (7) ◽  
pp. 2000
Author(s):  
Hongya Li ◽  
Laiqun Jin ◽  
Yuanyao Ding
Keyword(s):  
Growth Rate ◽  
Market Power ◽  
Firm Growth ◽  
Capital Intensity ◽  
Least Square ◽  
Export Demand ◽  
Negative Effects ◽  
Industrial Firms ◽  
New Generation ◽  
The Impact

In this paper, we provide empirical evidence for understanding the growth behavior of China’s new generation of information technology (IT) industrial firms and the impact of innovation and market power on them. Based on the data of China’s new generation IT industrial firms covering the period 2000–2007, we use ordinary least square (OLS) and two-stage least squares (IV-2SLS) methods to study the effects of innovation and markup on the growth of China’s new generation IT industrial firms in the framework of Gibrat’s law. IV-2SLS estimations show that: (1) Innovation and markup have positive and significant effects on the firm’s total revenue growth rate, but have no significant or negative effects on the growth rate of the firm’s total assets and employment. (2) Innovation has a positive and significant effect on the firm’s mark-up. The results indicate that for China’s new generation IT industrial firms which are technology-intensive, improving the technological innovation and market power will reduce the firm’s input and increase the firm’s output. Innovation can significantly increase the firm’s mark-up. (3) From the perspective of the dynamic evolution of a firm’s growth, firm size has a negative and significant impact on the firm growth while firm age has a positive and significant impact on the firm’s growth. In addition, we also examine the different effects of capital intensity and export demand on the firm’s growth.

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