Influence of pH on green synthesis of Ag nanoparticles

Velgosová, Oksana; Mražíková, Anna; Marcinčáková, R.

doi:10.1016/j.matlet.2016.04.045

Cited by 80 publications

(43 citation statements)

References 21 publications

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“…However, insignificant changes in the red-shift of the SPR band (from 432 to 434 nm) were observed after a long storage (range 30-150 days) suggesting a good stability of the prepared AgNPs for a long time. The intensity of the SPR bands gradually increased over time due to the continuous synthesis of AgNPs [19,20]. As shown in Fig.…”

Section: Resultsmentioning

confidence: 86%

Stability of Synthesized Silver Nanoparticles in Citrate and Mixed Gelatin/Citrate Solution

Kavuličová¹,

Mražíková²,

Velgosová³

et al. 2018

Acta Polytech

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Abstract. The study focuses on an investigation of the influence of both citrate and mixed gelatin/citrate as a reductant and stabilizer on the colloidal stability of silver nanoparticles (AgNPs) synthesized by a chemical reduction of Ag + ions after a short-(7th day) and long-(118th day) term storage. Formed AgNPs were characterized by a UV-vis Spectroscopy, Transmission Electron Microscope (TEM), Dynamic light scattering (DLS) and Zeta-potential (ZP). The obtained results revealed that a short-term stability of the synthesized AgNPs was greatly influenced by a citrate stabilizer with the absence of gelatin. Smaller-sized AgNPs (average particle diameter of 3 nm), roughly spherical in a shape, were obtained with a narrow size distribution. The very negative value of the Zeta-potential confirmed a strong stability of the citrate capped AgNPs. However, a surface coating of the AgNPs by a gelatin/citrate stabilizer was found to be a dominant contributor in improving a long-term stability of the AgNPs (average particle diameter of 26 nm). The use of gelatin in mixed stabilizer solution provided the AgNPs with higher monodispersity and a controllable size after both the short and long-term storage.

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Section: Resultsmentioning

confidence: 86%

Stability of Synthesized Silver Nanoparticles in Citrate and Mixed Gelatin/Citrate Solution

Kavuličová¹,

Mražíková²,

Velgosová³

et al. 2018

Acta Polytech

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“…The maximum absorption band of AgNPs in this work is 450 nm. The region of 350-450 nm is typical for the maximum absorption band of AgNPs [13]. The broad and asymmetrical peak of the UV-Visible absorption band of the synthesized AgNPs indicates AgNPs with a broad interval of size and non-uniform shape.…”

Section: Uv-visible Spectrophotometrymentioning

confidence: 95%

Green synthesis of silver nanoparticle using rambutan (Nephelium lappaceum L.) peel extract and its antibacterial activity against Salmonella parathypi A.

2018

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Abstract. Ag nanoparticles (AgNPs) have been synthesized via green method using rambutan (Nephelium lappaceum L.) peel (RP) extract. RP extract was prepared by washing the RP using tap water thoroughly and boiling it in distilled water at 70°C for 60 min. RP extract and AgNO3 were used as the starting materials for the synthesis of AgNPs. RP extract was added to 10 -3 M AgNO3 solution with a ratio by volume of 1:10 (RP : AgNO3), stirred at room temperature. The solution's color changes from reddish to dark brown, indicating the reduction of Ag + in the solution. The synthesized AgNPs were characterized using UV-Visible Spectrophotometer, FTIR Spectrophotometer, and Scanning Electron Microscopy-Energy-dispersive X-ray Spectroscopy (SEM-EDS) instruments. UV-Visible spectra show that the AgNPs have the maximum absorption band at 450 nm which is typical for AgNPs. The FTIR spectra revealed that the protein in RP extract acts as the capping agent for the synthesized AgNPs. The synthesized AgNPs were tested for their antibacterial activity against Salmonella parathypi A. The antibacterial test shows that 50 µL of AgNPs resulted in the inhibition zone of 4 mm against the aforementioned microorganism.

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“…1, what confirmed the presence of AgNPs in all experimental solutions. The colour change is the result of the radiation absorption in the visible region of the electromagnetic spectrum (380 -450 nm) due to the localised surface plasmon of AgNPs [20][21][22]. UV-vis spectra on Fig.…”

Section: Resultsmentioning

confidence: 99%

Limitations and possibilities of green synthesis and long-term stability of colloidal Ag nanoparticles

Velgosová

Mražíková

2017

AIP Conference Proceedings

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Abstract. In this paper the influence of algae life cycle and the solutions pH on the green synthesis of colloidal Ag nanoparticles (AgNPs) as well as effect of different storage conditions on AgNPs long-term stability was investigated. Silver nanoparticles were biologically synthesized using extracts of Parachlorella kessleri algae cultivated 1, 2, 3 and 4 weeks. The formation of AgNPs was monitored using a UV-vis spectrophotometer and verified by TEM observation. The results confirmed formation of polyhedron and/or near polyhedron AgNPs, ranging between 5 and 60 nm in diameter. The age of algae influenced the synthesis rate and an amount of AgNPs in solution. The best results were obtained using tree weeks old algae. UV-vis analysis and TEM observation also revealed that the size and the stability of AgNPs depend on the pH of solution. AgNPs formed in solutions of higher pH (8 and 10) are polyhedron, fine, with narrow size interval and stabile. Nanoparticles formed in solutions of low pH (2, 4 and 6) started to lose their stability on 10 th day of experiment, and the particle size interval was wide. The long-term stability of AgNPs can be influenced by light and temperature conditions. The most significant stability loss was observed at day light and room temperature (21°C). After 200-days significant amount of agglomerated particles settled on the bottom of the Erlenmeyer flask. AgNPs stored at dark and room temperature showed better long-term stability, weak particles agglomeration was observed. AgNPs stored at dark and at temperature 5°C showed the best long-term stability. Such AgNPs remained spherical, fine (5-20 nm), with narrow size interval and stable (no agglomeration) even after more than six months.

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Influence of pH on green synthesis of Ag nanoparticles

Cited by 80 publications

References 21 publications

Stability of Synthesized Silver Nanoparticles in Citrate and Mixed Gelatin/Citrate Solution

Stability of Synthesized Silver Nanoparticles in Citrate and Mixed Gelatin/Citrate Solution

Green synthesis of silver nanoparticle using rambutan (Nephelium lappaceum L.) peel extract and its antibacterial activity against Salmonella parathypi A.

Limitations and possibilities of green synthesis and long-term stability of colloidal Ag nanoparticles

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