scholarly journals Green Method for Synthesis of Gold Nanoparticles Using Polyscias scutellaria Leaf Extract under UV Light and Their Catalytic Activity to Reduce Methylene Blue

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Yoki Yulizar ◽  
Tresye Utari ◽  
Harits Atika Ariyanta ◽  
Digha Maulina
Keyword(s):  
Methylene Blue ◽  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Leaf Extract ◽  
Uv Light ◽  
Reduction Rate ◽  
Hydroxyl Groups ◽  
Face Centered Cubic ◽  
Pseudo First Order Reaction ◽  
Aqueous Fraction

The aqueous fraction of Polyscias scutellaria leaf extract (PSE) has been used as a reducing agent and stabilizer in the green synthesis of gold nanoparticles (AuNPs). UV-Vis spectrophotometry, particle size analyzer (PSA), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy-selected area electron diffraction (TEM-SAED), and X-ray diffraction (XRD) were used to characterize AuNPs. The AuNPs have a size of 5–20 nm and have a face centered cubic (fcc) crystal structure and are stable for 21 days. Phenolic compounds, which are secondary metabolites of PSE, act as an active compound to reduce Au3+ ion to Au0, as well as stabilize the AuNPs through their surface interaction with carbonyl and hydroxyl groups of phenols. AuNPs exhibit excellent catalytic activity for the reduction of methylene blue with NaBH4. The reduction of methylene blue using AuNPs catalysts is a pseudo-first-order reaction with a reduction rate constant (kobs) of 0.0223 min−1.

scholarly journals Design and Synthesis of Metal Complexes of (2E)-2-[(2E)-3-Phenylprop-2-en-1-ylidene]hydrazinecarbothioamide and Their Photocatalytic Degradation of Methylene Blue

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
P. Murali Krishna ◽  
N. B. Gopal Reddy ◽  
Nagaraju Kottam ◽  
B. C. Yallur ◽  
Hussain Reddy Katreddi
Keyword(s):  
Methylene Blue ◽  
Catalytic Activity ◽  
Metal Complexes ◽  
Photocatalytic Degradation ◽  
Organic Pollutants ◽  
Metal Ion ◽  
Uv Light ◽  
Cationic Dye ◽  
Design And Synthesis ◽  
Effects Of Ph

The photocatalytic degradation has been considered to be an efficient process for the degradation of organic pollutants, which are present in the effluents released by industries. The photocatalytic bleaching of cationic dye methylene blue was carried out spectrometrically on irradiation of UV light using Cu(II), Ni(II), and Co(II) complexes of (2E)-2-[(2E)-3-phenylprop-2-en-1-ylidene]hydrazinecarbothioamide (HL). The effects of pH and metal ion were studied on the efficiency of the reaction. Cu(II) complex shows better catalytic activity and the highest percentage degradation (~88.8%) of methylene blue was observed at pH 12. A tentative mechanism has also been proposed for the photocatalytic degradation of methylene blue.

scholarly journals Shape-Dependent Catalytic Activity of Gold and Bimetallic Nanoparticles in the Reduction of Methylene Blue by Sodium Borohydride

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1442
Author(s):  
Heike Lisa Kerstin Stephanie Stolle ◽  
Jonas Jakobus Kluitmann ◽  
Andrea Csáki ◽  
Johann Michael Köhler ◽  
Wolfgang Fritzsche
Keyword(s):  
Methylene Blue ◽  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Surface Area ◽  
Sodium Borohydride ◽  
Bimetallic Nanoparticles ◽  
Pure Gold ◽  
Gold Nanoprisms ◽  
Bimetallic Nanorods ◽  
The Impact

In this study the catalytic activity of different gold and bimetallic nanoparticle solutions towards the reduction of methylene blue by sodium borohydride as a model reaction is investigated. By utilizing differently shaped gold nanoparticles, i.e., spheres, cubes, prisms and rods as well as bimetallic gold–palladium and gold–platinum core-shell nanorods, we evaluate the effect of the catalyst surface area as available gold surface area, the shape of the nanoparticles and the impact of added secondary metals in case of bimetallic nanorods. We track the reaction by UV/Vis measurements in the range of 190–850 nm every 60 s. It is assumed that the gold nanoparticles do not only act as a unit transferring electrons from sodium borohydride towards methylene blue but can promote the electron transfer upon plasmonic excitation. By testing different particle shapes, we could indeed demonstrate an effect of the particle shape by excluding the impact of surface area and/or surface ligands. All nanoparticle solutions showed a higher methylene blue turnover than their reference, whereby gold nanoprisms exhibited 100% turnover as no further methylene blue absorption peak was detected. The reaction rate constant k was also determined and revealed overall quicker reactions when gold or bimetallic nanoparticles were added as a catalyst, and again these were highest for nanoprisms. Furthermore, when comparing gold and bimetallic nanorods, it could be shown that through the addition of the catalytically active second metal platinum or palladium, the dye turnover was accelerated and degradation rate constants were higher compared to those of pure gold nanorods. The results explore the catalytic activity of nanoparticles, and assist in exploring further catalytic applications.

scholarly journals Photocatalytic degradation of methylene blue dye solution using different amount of ZnO as a photocatalyst

2021 ◽  
Vol 15 (1) ◽  
pp. 1
Author(s):  
Hartini Ahmad Rafaie ◽  
Nur Fitrahana Mohd Yusop ◽  
Nurathira Faqihah Azmi ◽  
Nur Syakirah Abdullah ◽  
Nurul Infaza Talalah Ramli
Keyword(s):  
Methylene Blue ◽  
Zinc Oxide ◽  
Photocatalytic Degradation ◽  
Uv Light ◽  
Blue Dye ◽  
X Ray Diffraction ◽  
Pseudo First Order Reaction ◽  
Photodegradation Rate ◽  
Photocatalytic Activities ◽  
Zno Powder

Zinc oxide (ZnO) powder was used as a photocatalyst for the photocatalytic degradation of methylene blue (MB) dye solution. In this study, different amount of ZnO (10, 20 and 30 mg) as photocatalyst was used to investigate the performance of photocatalytic degradation of MB dye solution. The morphology and structural properties of ZnO powder were studied by X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) techniques. The photocatalytic activities of the ZnO powder were investigated by degrading the MB dye solution under UV light irradiation at different amounts of ZnO photocatalyst. The percentage degradation of MB dye solution in the presence of 10 mg ZnO powder was found to be the highest at 96.2 % within 60 min irradiation compared to 20 and 30 mg of ZnO powder. The photodegradation rate constants, k obtained in this study were 0.0661, 0.0558, and 0.0507 min-1 for 10, 20, and 30 mg ZnO powder, respectively that follow the pseudo first-order reaction kinetics. Keywords: Methylene blue, photocatalytic degradation, photocatalyst, Zinc Oxide

scholarly journals Synthesis, characterization and functional evaluation of gold nanoparticles prepared using Dovyalis abyssinica leaf extracts as reducing and surface capping agent

2021 ◽  
Vol 14 (2) ◽  
pp. 171-190
Author(s):  
Abera Beyene Gebresilassie ◽  
Adam Mekonnen Engida
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Plant Extract ◽  
Radical Scavenging ◽  
Diffraction Spectrum ◽  
Functional Evaluation ◽  
Capping Agent ◽  
Aqueous Fraction ◽  
Au Nps ◽  
Surface Capping

Green synthesis of nanoparticles using plants and microorganisms is biologically safe, cost effective, and environmentally friendly technology. Gold nanoparticles (Au NPs) were synthesized using aqueous extracts of leaves of Dovyalis abyssinica as reducing and surface capping agent and the catalytic activity, antibacterial action and antioxidant potential of the synthesized AU NPs were evaluated. Firstly, HAuCl4 was synthesized in the laboratory from metallic gold and hydrochloric acid using a predesigned method. Secondly, Au NPs was synthesized by mixing HAuCl4 and the plant extract at 45 oC with a digestion time of 1 h. The size of the nanoparticles was modulated by varying the ratio of the plant extract and HAuCl4 with known concentrations. The synthesized Au NPs showed strong absorption around 540 nm which lies in the characteristic absorption region of Au metal nanoparticles (520–580 nm). The X-ray diffraction spectrum of the synthesized Au NPs showed characteristic crystalline structures of gold. The scanning electron spectroscopy images of the synthesized Au NPS revealed the presence of mixed shapes predominantly of irregular shapes and a particle size analyzer displayed an average size of 63.13 nm. The fourier-transform infrared spectrum of Au NPS confirmed the presence of amine, carbonyl and hydroxyl functional groups as surface capping molecules. Although the synthesized Au NPs showed poor bacterial growth inhibition activity on two selected bacteria, it demonstrated excellent free radical scavenging activity against 2, 2-Diphenyl-2-picrylhydrazyl (DPPH) radical and good catalytic activity for degrading bromothymol blue and methyl red compounds. In contrast to the hexane and ethyl acetate extracts, the aqueous fraction was identified as powerful reducing fraction for the synthesis of Au NPs in this experiment. 

scholarly journals Reduction mechanisms of Ag(I) and Au(III) in the synthesis of silver and gold nanoparticles using leaf extract of Terminalia catappa

2021 ◽  
Vol 21 (2) ◽  
pp. 89-98
Author(s):  
MUHAMMAD ZAKIR ◽  
MAMING MAMING ◽  
MISKA SANDA LEMBANG ◽  
ESTY YURNITA LEMBANG
Keyword(s):  
Gold Nanoparticles ◽  
Silver Nanoparticles ◽  
Leaf Extract ◽  
Hydroxyl Groups ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
Terminalia Catappa ◽  
Particle Size Analyzer ◽  
Reduction Mechanisms ◽  
Average Size

Synthesis of silver nanoparticles (AgNP) and gold nanoparticles (AuNP) was carried out by the reduction method with leaf extract of Ketapang (Terminalia catappa). The biomolecules present in the extract generated the reduction of Ag+ and Au3+ ions from AgNO3 and HAuCl4, respectively. The growth of nanoparticles was monitored by UV-Vis spectrophotometer. The maximum absorption of biosynthesis of AgNP and AuNP were observed in the respective range of 421-431nm and 530-535nm. Those peaks correspond to surface plasmon absorbance of AgNP and AuNP, respectively. Analysis on the functional groups change of the extract by Fourier Transform Infra Red (FTIR) Spectroscopy showed the formation of carbonyl- from hydroxyl-groups which suggested the oxidation and reduction processes involved in the formation of both nanoparticles. The average size distributions determined by PSA (Particle Size Analyzer) are 55-71nm and 18-44nm for AgNP and AuNP, respectively. Morphology of the silver nanoparticles was observed by Scanning Electron Microscope (SEM) and the structure of the compounds was characterized using X-ray Diffraction (XRD). The shape of AgNP varied from triangular, cubic and hexagonal polyshaped, while AuNP were spherical. XRD studies showed that the nanoparticles obtained were crystalline gold and silver.

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