scholarly journals Biosynthesis of Ag/almond shell nanocomposite as a cost-effective and efficient catalyst for degradation of 4-nitrophenol and organic dyes

RSC Advances ◽  
2017 ◽  
Vol 7 (1) ◽  
pp. 180-189 ◽  
Author(s):  
Maryam Bordbar

Silver nanoparticles have been immobilized on the surface of waste almond shell using Ruta graveolens sleeves extract as a reducing and stabilizing agent in the present work.

2020 ◽  
Vol 9 (1) ◽  
pp. 451-461 ◽  
Author(s):  
Abid Hussain ◽  
Ansar Mehmood ◽  
Ghulam Murtaza ◽  
Khawaja Shafique Ahmad ◽  
Aneela Ulfat ◽  
...  

AbstractIn this study, we reported an easy, rapid, cost-effective and environmentally benign method for the fabrication of silver nanoparticles (Ag-NPs) using Olea ferruginea as reducing, capping and stabilizing agent. For this, an aqueous extract of leaf and bark of O. ferruginea was treated with 1 mM AgNO3, which reduces Ag ions to Ag-NPs by establishing reddish brown color. The synthesized Ag-NPs were spherical crystals, with a mean size of 23 and 17 nm for leaf- and bark-mediated Ag-NPs, respectively. Fourier transform infrared spectroscopy affirmed the role of leaf and bark extracts of O. ferruginea as reducing, capping and stabilizing agent. These biosynthesized Ag-NPs showed profound antibacterial activity against Gram-negative (Pseudomonas aeruginosa and Escherichia coli) and Gram-positive (Streptococcus pneumonia and Staphylococcus aureus) bacteria. The highest antibacterial activity was shown by bark Ag-NPs against S. aureus (14.00 mm), while leaf Ag-NPs showed higher activity against S. pneumonia (13.00 mm). Additionally, they produced effective antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) as compared to plant extracts and positive control. It was observed that the bark-mediated Ag-NPs had higher percentage (90%) of scavenging potential than the leaf-mediated Ag-NPs (78%). The significance of the current study is the synthesis of eco-friendly, easy and cost-effective Ag-NPs as biomedical products.


2021 ◽  
Vol 14 ◽  
Author(s):  
Olfat M. El-Monairy ◽  
Ahmed A. El-Sayed ◽  
Manar M. Emara ◽  
Abla D. Abdel-Meguid

Background: Metal nanoparticles synthesized by various chemical reactions have significantly gained worldwide interest for their use in biomedical applications. These processes exhibit a broad range of toxicity in none target organisms. To avoid the chemical toxicity, green synthesis of metal nanoparticles is proposed as a cost-effective and eco-friendly alternative. Aloe vera (A. vera) leaf extract is a medicinal agent with multiple properties including antibacterial effect. Its constituents include lignin, pectin and hemicellulose which can be used in the reduction of silver ions to produce silver nanoparticles (AgNPs). Objective: The aim of this article is to study the use of naturally occurring compounds as a reducing and stabilizing agent for the biosynthesis of nanoparticles and to investigate the insecticidal activity of these compounds against Musca domestica (M. domestica) larvae. Methods: Phytochemical analysis of A. vera gel extract was performed and the phytochemical components identified by Gas chromatography–mass spectrometry (GC-MS) analysis. AgNPs and encapsulated chitosan nanoparticles (CsNPs) were prepared by an eco-friendly method using A. vera gel extract as a reducing and stabilizing agent. A. vera-AgNPs and A. vera encapsulated CsNPs were characterized using Ultraviolet-visible spectrophotometer (UV–vis spectrum), Transmission Electron Microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Then, the insecticidal activity of these compounds was investigated against late second instar larvae of house fly. Results: : The most active ingredients identified by GC-MS analysis were Terpene and Sesquiterpens hydrocarbons. The synthesized AgNPs were spherical with average size about 12-75 nm as revealed by TEM. While encapsulated CsNPs were ranged between 34-75 nm and the shape seems spherical with dark parts confirmed the capsulated plant extract. FTIR and XRD confirmed the successful encapsulation of the gel extract within the chitosan nanoparticles. Results proved the insecticidal potential of the tested compounds against M. domestica larvae and the relative potency of encapsulated CsNPs was nearly 148.51 times more potent than A. vera crude extract whereas, AgNPs was nearly 40.65 times more potent than A. vera crude extract. Furthermore, a prolongation of larval duration and reduction in the percentage pupation and adult emergence were observed. Conclusion: Overall, green-synthesized silver and chitosan nanoparticles are used as a biopesticide for house fly control through safer and cost-effective approach.


2019 ◽  
Vol 4 (2) ◽  
pp. 112-124
Author(s):  
Edward K.B. Bragais ◽  
Lynne M. Labaclado

Background and Objective: In this study, dudoa (Hydnocarpus alcalae C.DC.) leaf extract was used as a reducing and stabilizing agent in a novel one-step green synthesis of silver nanoparticles. Dudoa is an endemic plant in the province of Legazpi, Philippines and its seed oil was used as an anti-leprotic drug. Method: Therefore, the dudoa leaf extract was used to synthesize silver nanoparticles. Moreover, optimization of various parameters greatly affected the size and morphology of the synthesized AgNPs as indicated by the Ultraviolet-visible (UV-vis) spectrophotometry. The synthesized AgNPs were further characterized using spectral analyses such as XRD, EDX, SEM, FT-IR, TGA and DLS. The antimicrobial activity of synthesized AgNPs was also demonstrated. Results and Discussions: The synthesized AgNPs exhibited a diffraction pattern and a particle size ranging from 22-48 nm. The AgNPs also showed complete inhibitory and mild reactivity against representative pathogenic gram-positive (S.aureus) and gram-negative (E.coli) bacteria. Conclusion: Silver nanoparticles were successfully synthesized using H. alcalae leaf extract. Furthermore, this green synthesis approach appeared to be cost-effective, non-toxic, and eco-friendly which is a best alternative to the conventional chemical methods.


2019 ◽  
Vol 48 (3) ◽  
pp. 1051-1059 ◽  
Author(s):  
Rui-Lei Wang ◽  
Dong-Peng Li ◽  
Lu-Jie Wang ◽  
Xiao Zhang ◽  
Zi-Yan Zhou ◽  
...  

Ag@TPHH-COF can be used as efficient catalyst for the reduction of the various nitroaromatic compounds and organic dyes in industrial wastewater.


2019 ◽  
Vol 25 (34) ◽  
pp. 3645-3663 ◽  
Author(s):  
Muhammad Ismail ◽  
Kalsoom Akhtar ◽  
M.I. Khan ◽  
Tahseen Kamal ◽  
Murad A. Khan ◽  
...  

: Water pollution due to waste effluents of the textile industry is seriously causing various health problems in humans. Water pollution with pathogenic bacteria, especially Escherichia coli (E. coli) and other microbes is due to the mixing of fecal material with drinking water, industrial and domestic sewage, pasture and agricultural runoff. Among the chemical pollutants, organic dyes due to toxic nature, are one of the major contaminants of industrial wastewater. Adequate sanitation services and drinking quality water would eliminate 200 million cases of diarrhea, which results in 2.1 million less deaths caused by diarrheal disease due to E. coli each year. Nanotechnology is an excellent platform as compared to conventional treatment methods of water treatment and remediation from microorganisms and organic dyes. In the current study, toxicity and carcinogenicity of the organic dyes have been studied as well as the remediation/inactivation of dyes and microorganism has been discussed. Remediation by biological, physical and chemical methods has been reviewed critically. A physical process like adsorption is cost-effective, but can’t degrade dyes. Biological methods were considered to be ecofriendly and cost-effective. Microbiological degradation of dyes is cost-effective, eco-friendly and alternative to the chemical reduction. Besides, certain enzymes especially horseradish peroxidase are used as versatile catalysts in a number of industrial processes. Moreover, this document has been prepared by gathering recent research works related to the dyes and microbial pollution elimination from water sources by using heterogeneous photocatalysts, metal nanoparticles catalysts, metal oxides and enzymes.


2020 ◽  
Vol 13 ◽  
Author(s):  
Kumari Jyoti ◽  
Punyasloka Pattnaik ◽  
Tej Singh

Background:: Synthesis of metallic nanoparticles has attracted extensive vitality in numerous research areas such as drug delivery, biomedicine, catalysis etc. where continuous efforts are being made by scientists and engineers to investigate new dimensions for both technological and industrial advancements. Amongst numerous metallic nanoparticles, silver nanoparticle (AgNPs) is a novel metal species with low toxicity, higher stability and significant chemical, physical and biological properties. Methods:: In this, various methods for the fabrication of AgNPs are summarized. Importantly, we concentrated on the role of reducing agents of different plants parts, various working conditions such as AgNO3 concentration; ratio of AgNO3/extract; incubation time; centrifugal conditions, size and shapes. Results:: This study suggested that eco-friendly and non toxic biomolecules present in the extracts (e.g. leaf, stem and root) of plants are used as reducing and capping agents for silver nanoparticles fabrication. This method of fabrication of silver nanoparticles using plants extracts is comparatively cost-effective and simple. A silver salt is simply reduced by biomolecules present in the extracts of these plants. In this review, we have emphasized the synthesis and antibacterial potential of silver nanoparticles using various plant extracts. Conclusion:: Fabrication of silver nanoparticles using plant extracts have advantage over the other physical methods, as it is safe, eco-friendly and simple to use. Plants have huge potential for the fabrication of silver nanoparticles of wide potential of applications with desired shape and size.


Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 613
Author(s):  
Sankar Sekar ◽  
Sejoon Lee

High-quality silicon (Si) nanocrystals that simultaneously had superior mesoporous and luminescent characteristics were derived from sticky, red, and brown rice husks via the facile and cost-effective magnesiothermic reduction method. The Si nanocrystals were confirmed to comprise an aggregated morphology with spherical nanocrystals (e.g., average sizes of 15–50 nm). Due to the surface functional groups formed at the nanocrystalline Si surfaces, the Si nanocrystals clearly exhibited multiple luminescence peaks in visible-wavelength regions (i.e., blue, green, and yellow light). Among the synthesized Si nanocrystals, additionally, the brown rice husk (BRH)-derived Si nanocrystals showed to have a strong UV absorption and a high porosity (i.e., large specific surface area: 265.6 m2/g, small average pore diameter: 1.91 nm, and large total pore volume: 0.5389 cm3/g). These are indicative of the excellent optical and textural characteristics of the BRH-derived Si nanocrystals, compared to previously reported biomass-derived Si nanocrystals. The results suggest that the biomass BRH-derived Si nanocrystals hold great potential as an active source material for optoelectronic devices as well as a highly efficient catalyst or photocatalyst for energy conversion devices.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Ram Prasad ◽  
Vyshnava Satyanarayana Swamy

The unique property of the silver nanoparticles having the antimicrobial activity drags the major attention towards the present nanotechnology. The environmentally nontoxic, ecofriendly, and cost-effective method that has been developed for the synthesis of silver nanoparticles using plant extracts creates the major research interest in the field of nanobiotechnology. The synthesized silver nanoparticles have been characterized by the UV-visible spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM). Further, the antibacterial activity of silver nanoparticles was evaluated by well diffusion method, and it was found that the biogenic silver nanoparticles have antibacterial activity against Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 29213), Pseudomonas aeruginosa (ATCC 27853), Azotobacter chroococcum WR 9, and Bacillus licheniformis (MTCC 9555).


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