scholarly journals Synthesis of Gold Nanoparticles Using Tannin-Rich Extract and Coating onto Cotton Textiles for Catalytic Degradation of Congo Red

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Penwisa Pisitsak ◽  
Kwandee Chamchoy ◽  
Varanrada Chinprateep ◽  
Wiphawan Khobthong ◽  
Pisutsaran Chitichotpanya ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Gold Nanoparticles ◽  
Congo Red ◽  
Catalytic Reduction ◽  
Average Diameter ◽  
Chloroauric Acid ◽  
Ambient Conditions ◽  
Transmission Electron ◽  
Cr Concentration ◽  
Coated Fabrics

Gold nanoparticles (AuNPs) were synthesized under ambient conditions from chloroauric acid in aqueous solution at pH 4. Tannin-rich extract from Xylocarpus granatum bark was used as both reducing and capping agent, rapidly converting Au (I) salt to AuNPs. Transmission electron microscopy showed the as-prepared AuNPs to be predominantly spherical, with an average diameter of 17 nm. The AuNPs were tested for catalytic reduction of Congo red (CR), a carcinogenic azo dye, in aqueous sodium borohydride solution. Cotton samples were coated with the AuNPs, taking on a reddish-purple color. The samples showed significantly reduced tearing strength after coating, though tensile strength was unaffected. UV-visible spectroscopy was used to determine the dye concentration in the water. CR degradation was observed only when AuNPs were present, and the efficiency of degradation was strongly linked to the AuNP loading. The AuNP-coated fabrics left only a 4.7% CR concentration in the solution after 24 h and therefore promise as a heterogeneous catalyst for degradation of CR in aqueous solution.

scholarly journals Green Synthesis of Silver and Gold Nanoparticles via Sargassum serratifolium Extract for Catalytic Reduction of Organic Dyes

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 347
Author(s):  
Beomjin Kim ◽  
Woo Chang Song ◽  
Sun Young Park ◽  
Geuntae Park
Keyword(s):  
Gold Nanoparticles ◽  
Green Synthesis ◽  
Catalytic Reduction ◽  
Organic Dyes ◽  
Low Cost ◽  
Inorganic Nanoparticles ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Sargassum Serratifolium

The green synthesis of inorganic nanoparticles (NPs) using bio-materials has attained enormous attention in recent years due to its simple, eco-friendly, low-cost and non-toxic nature. In this work, silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) were synthesized by the marine algae extract, Sargassum serratifolium (SS). The characteristic studies of bio-synthesized SS-AgNPs and SS-AuNPs were carried out by using ultraviolet–visible (UV–Vis) absorption spectroscopy, dynamic light scattering (DLS), high-resolution transmission electron microscope (HR-TEM), selected area electron diffraction (SAED), energy-dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Phytochemicals in the algae extract, such as meroterpenoids, acted as a capping agent for the NPs’ growth. The synthesized Ag and Au NPs were found to have important catalytic activity for the degradation of organic dyes, including methylene blue, rhodamine B and methyl orange. The reduction of dyes by SS-AgNPs and -AuNPs followed the pseudo-first order kinetics.

scholarly journals Exploration of the Antimicrobial and Catalytic Properties of Gold Nanoparticles Greenly Synthesized by Cryptolepis buchanani Roem. and Schult Extract

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Kamonpan Wongyai ◽  
Phitchayapak Wintachai ◽  
Rasimate Maungchang ◽  
Parawee Rattanakit
Keyword(s):  
Staphylococcus Aureus ◽  
Gold Nanoparticles ◽  
Analytical Techniques ◽  
Average Diameter ◽  
Face Centered Cubic ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Face Centered

A green, simple, and rapid synthesis of gold nanoparticles using plant extract, Cryptolepis buchanani Roem. and Schult, and their applications are first described in this paper. The formation of gold nanoparticles was visually observed by the appearance of a ruby red color, which was further indicated by an absorption peak at 530 nm in UV-Vis spectroscopy. Optimization of reaction parameters for the gold nanoparticles was also investigated. Various analytical techniques were employed as part of the process of characterizing the resulting gold nanoparticles. Fourier transform infrared (FTIR) analysis revealed that the phenol compounds present in the extract were responsible for gold(III) reduction and stabilization of gold nanoparticles. Transmission electron microscopy (TEM) analysis showed that the gold nanoparticles were spherical in shape with an average diameter of 11 nm. Powder X-ray diffraction (XRD) pattern indicated that the green synthesis approach produced highly crystalline, face-centered cubic gold nanoparticles. Energy-dispersive X-ray spectroscopy (EDS) measurements confirmed the presence of elemental gold in the prepared nanoparticles. The negative zeta potential value of gold nanoparticles was found to be -30.28 mV. The green synthesized gold nanoparticles expressed effective antibacterial activity against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Acinetobacter baumannii and exhibited an excellent catalytic property in terms of its reduction ability of methylene blue.

Synthesis of Gold Nanoparticles Using Glutamic Acid as a Reductor and Capping Agent

2020 ◽  
Vol 840 ◽  
pp. 472-477
Author(s):  
Naura Nadhifah ◽  
Wening Rara Pratita ◽  
Eko Sri Kunarti ◽  
Nuryono Nuryono ◽  
Sri Juari Santosa
Keyword(s):  
Gold Nanoparticles ◽  
Acid Solution ◽  
Glutamic Acid ◽  
Color Change ◽  
Reaction Times ◽  
Chloroauric Acid ◽  
Optimum Synthesis ◽  
Transmission Electron ◽  
Particle Size Analyzer ◽  
Uv Visible

The synthesis of gold nanoparticles (AuNPs) was carried out by reacting chloroauric acid [AuCl4]‒ and glutamic acid solution in a water bath at 80 °C. The reaction was confirmed by the color change from colorless solution into pink. Various concentrations of the glutamic acid solution, reaction times and pH were examined to determine the optimum condition of AuNPs synthesis. The AuNPs colloid was characterized by UV-Visible spectrophotometer at wavelength 350-800 nm, particle size analyzer (PSA) and transmission electron microscope (TEM). The optimum synthesis condition for obtained [AuCl4]‒ was 4 mM glutamic acid solution at pH 11 and 60 min reaction. TEM results showed that the particles were round in shape with the article size indicated by PSA was 40 nm.

Adsorption of Congo Red from Aqueous Solution onto Chitosan/Rectorite Composite

2013 ◽  
Vol 690-693 ◽  
pp. 438-441 ◽  
Author(s):  
Tao Feng ◽  
Lei Xu
Keyword(s):  
Aqueous Solution ◽  
Adsorption Kinetics ◽  
Congo Red ◽  
Adsorption Process ◽  
Order Equation ◽  
Interlayer Distance ◽  
Kinetics Studies ◽  
Pseudo Second Order ◽  
Cr Concentration ◽  
Cr Uptake

The chitosan/rectorite composite was prepared and characterized by XRD. The interlayer distance of rectorite was enlarged from 2.53 nm to 3.01 nm. Congo red (CR) was selected as a model anionic dye and the adsorption tests of CR onto chitosan/rectorite composite were carried out. The results showed that the CR adsorption process is dependent on pH and initial CR concentration and temperature. The maximal CR uptake by chitosan/rectorite composite was 73.8 mg g-1 in the test. Adsorption kinetics studies indicated that the sorption processes were better fitted by pseudo-second order equation.

scholarly journals Role of Surfactant in the Formation of Gold Nanoparticles in Aqueous Medium

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Abhishek Das ◽  
Ridhima Chadha ◽  
Nandita Maiti ◽  
Sudhir Kapoor
Keyword(s):  
Gold Nanoparticles ◽  
Aqueous Medium ◽  
Sodium Dodecyl ◽  
Chloroauric Acid ◽  
Synthesis Mechanism ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
The Stability ◽  
Mediated Reduction

The stability of gold nanoparticles is a major issue which decides their impending usage in nanobiotechnological applications. Often biomimetically synthesized nanoparticles are deemed useless owing to their instability in aqueous medium. So, surfactants are used to stabilize the nanoparticles. But does the surfactant only stabilize by being adsorbed to the surface of the nanoparticles and not play significantly in moulding the size and shape of the nanoparticles? Keeping this idea in mind, gold nanoparticles (GNPs) synthesized by l-tryptophan (Trp) mediated reduction of chloroauric acid (HAuCl4) were stabilized by anionic surfactant, sodium dodecyl sulphate (SDS), and its effect on the moulding of size and properties of the GNPs was studied. Interestingly, unlike most of the gold nanoparticles synthesis mechanism showing saturation growth mechanism, inclusion of SDS in the reaction mixture for GNPs synthesis resulted in a bimodal mechanism which was studied by UV-Vis spectroscopy. The mechanism was further substantiated with transmission electron microscopy. Zeta potential of GNPs solutions was measured to corroborate stability observations recorded visually.

A Simple Method to Self-Assemble Two-dimensional and Three-dimensional Superlattices of Gold Nanoparticles

2007 ◽  
Vol 1056 ◽  
Author(s):  
Tao Fu ◽  
Hai-Yan Qin ◽  
Wen-Jiang Li ◽  
Sailing He
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Particle Dispersion ◽  
Diameter Distribution ◽  
Chloroauric Acid ◽  
Two Dimensional ◽  
Visible Absorption ◽  
Simple Method ◽  
Transmission Electron

ABSTRACTCitrate-capped gold nanoparticles with narrow diameter distribution were prepared by the reduction of chloroauric acid with borohydride. After the gold nanoparticles were transferred to toluene solution through ligand conformation change, close-packed two-dimensional nanocrystal lattices were obtained on transmission electron microscopy (TEM) copper grids by evaporating approximately 10 μL of concentrated particle dispersion. The formation of the thiolate gold nanoparticles was investigated by UV-visible absorption spectroscopy and FTIR spectra. The 2D Fourier transform power spectra of the monolayer confirmed the supperlattices' hexagonal symmetry. Furthermore, long-range-ordered bilayer superlattices, of which the nanoparticles in the top layer piled on the ones in the bottom layer, could also be observed by transmission electron microscopy.

scholarly journals Caffeic Acid: Potential Applications in Nanotechnology as a Green Reducing Agent for Sustainable Synthesis of Gold Nanoparticles

2015 ◽  
Vol 10 (4) ◽  
pp. 1934578X1501000
Author(s):  
Yu Seon Seo ◽  
Song-Hyun Cha ◽  
Seonho Cho ◽  
Hye-Ran Yoon ◽  
Young-Hwa Kang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Caffeic Acid ◽  
Average Diameter ◽  
Reducing Agent ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Potential Applications ◽  
Acid Potential ◽  
Sustainability Initiatives

The sustainable synthesis of gold nanoparticles from gold ions was conducted with caffeic acid as a green reducing agent. The formation of gold nanoparticles was confirmed by spectroscopic and microscopic methods. Spherical nanoparticles with an average diameter of 29.99 ± 7.43 nm were observed in high-resolution transmission electron microscopy and atomic force microscopy images. The newly prepared gold nanoparticles exhibited catalytic activity toward the reduction of 4-nitrophenol to 4-aminophenol in the presence of sodium borohydride. This system enables the preparation of green catalysts using plant natural products as reducing agents, which fulfills the growing need for sustainability initiatives.

Preparation of Sub-Micrometre Size Platinum Particles via Chemical Reduction of Hexachloroplatinic Acid in Aqueous Solution

2014 ◽  
Vol 1058 ◽  
pp. 48-51
Author(s):  
Luan Liu ◽  
Jin Hu ◽  
Yu Tian Wang ◽  
Kai Jun Wang ◽  
Lin Su
Keyword(s):  
Aqueous Solution ◽  
Ftir Spectroscopy ◽  
Chemical Reduction ◽  
Average Diameter ◽  
Visible Spectroscopy ◽  
Hexachloroplatinic Acid ◽  
Transmission Electron ◽  
Platinum Particles ◽  
Uv Visible ◽  
Pvp K30

The sub-micrometre size platinum particles via chemical reduction of hexachloroplatinic acid in aqueous solution was investigated by UV-Visible Spectroscopy, Transmission Electron Microscopy, X-ray diffraction and FTIR Spectroscopy. Hydrazine hydrate was used as the reducing agent, and polyvinylpyrrolidone (PVP-K30) was used for stabilizing the particles. By varying the amount of PVP-K30 the average diameter of the platinum particles could be adjusted. The TEM and XRD results revealed that the final sub-micrometre size Pt particles were the result of an aggregation of small (~5 nm) nanoparticles. The UV-Visible Spectroscopy and FTIR Spectroscopy investigations indicates the mechanism of anti-aggregation of Pt particles by the steric effect of PVP-K30.

Synthesis of L-Phenylalanine Stabilized Gold Nanoparticles and Their Thermal Stability

2006 ◽  
Vol 6 (11) ◽  
pp. 3512-3516 ◽  
Author(s):  
Nimai C. Nayak ◽  
Kwanwoo Shin
Keyword(s):  
Thermal Stability ◽  
Gold Nanoparticles ◽  
Electron Microscope ◽  
Ambient Condition ◽  
Synthesis Methods ◽  
Chloroauric Acid ◽  
Borohydride Reduction ◽  
Thermal Stabilities ◽  
Transmission Electron ◽  
Vis Spectroscopy

Here we described the two synthesis methods of L-phenylalanine (L-phe) coated gold nanoparticles through a reduction of aqueous chloroaurate ions directly by L-phe, and also the borohydride reduction of chloroauric acid followed by capping with L-phe molecules. Phenylalanine reduced gold nanoparticles and the phenylalanine capped gold nanoparticles were evaluated by transmission electron microscope and UV-vis spectroscopy, and then their thermal stabilities were compared. We found that the phenylalanine reduced gold nanoparticles were unstable and form linearly arranged aggregates on aging, while as the phenylalanine capped gold nanoparticles were stable for months in ambient condition.

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