Enhanced catalytic reduction of 4-nitrophenol and congo red dye By silver nanoparticles prepared from Azadirachta indica leaf extract under direct sunlight exposure
“…Metallic NPs can promote the rate of reaction by increasing the adsorption of reactants on their surface, thereby diminishing activation energy barriers [ 119 , 120 ] (Fig. 8 ).…”
“… Fig. 8 Schematic of the metallic NP-mediated catalytic reduction of 4-nitrophenol to 4-aminophenol [ 120 ] Fig. 9 UV-visible spectra illustrating Chenopodium aristatum L. stem extract synthesized Ag NP-mediated catalytic reduction of 4-NP to 4-AP at three different temperatures a 30 °C, b 50 °C, and c 70 °C.…”
In materials science, “green” synthesis has gained extensive attention as a reliable, sustainable, and eco-friendly protocol for synthesizing a wide range of materials/nanomaterials including
metal/metal oxides nanomaterials, hybrid materials, and bioinspired materials. As such, green synthesis is regarded as an important tool to reduce the destructive effects associated with the traditional methods of synthesis for nanoparticles commonly utilized in laboratory and industry. In this review, we summarized the fundamental processes and mechanisms of “green” synthesis approaches, especially for metal and metal oxide [e.g., gold (Au), silver (Ag), copper oxide (CuO), and zinc oxide (ZnO)] nanoparticles using natural extracts. Importantly, we explored the role of biological components, essential phytochemicals (e.g., flavonoids, alkaloids, terpenoids, amides, and aldehydes) as reducing agents and solvent systems. The stability/toxicity of nanoparticles and the associated surface engineering techniques for achieving biocompatibility are also discussed. Finally, we covered applications of such synthesized products to environmental remediation in terms of antimicrobial activity, catalytic activity, removal of pollutants dyes, and heavy metal ion sensing.
“…Metallic NPs can promote the rate of reaction by increasing the adsorption of reactants on their surface, thereby diminishing activation energy barriers [ 119 , 120 ] (Fig. 8 ).…”
“… Fig. 8 Schematic of the metallic NP-mediated catalytic reduction of 4-nitrophenol to 4-aminophenol [ 120 ] Fig. 9 UV-visible spectra illustrating Chenopodium aristatum L. stem extract synthesized Ag NP-mediated catalytic reduction of 4-NP to 4-AP at three different temperatures a 30 °C, b 50 °C, and c 70 °C.…”
In materials science, “green” synthesis has gained extensive attention as a reliable, sustainable, and eco-friendly protocol for synthesizing a wide range of materials/nanomaterials including
metal/metal oxides nanomaterials, hybrid materials, and bioinspired materials. As such, green synthesis is regarded as an important tool to reduce the destructive effects associated with the traditional methods of synthesis for nanoparticles commonly utilized in laboratory and industry. In this review, we summarized the fundamental processes and mechanisms of “green” synthesis approaches, especially for metal and metal oxide [e.g., gold (Au), silver (Ag), copper oxide (CuO), and zinc oxide (ZnO)] nanoparticles using natural extracts. Importantly, we explored the role of biological components, essential phytochemicals (e.g., flavonoids, alkaloids, terpenoids, amides, and aldehydes) as reducing agents and solvent systems. The stability/toxicity of nanoparticles and the associated surface engineering techniques for achieving biocompatibility are also discussed. Finally, we covered applications of such synthesized products to environmental remediation in terms of antimicrobial activity, catalytic activity, removal of pollutants dyes, and heavy metal ion sensing.
“…Till date, there are various reports available in which many plant extracts were utilized for nanoparticles synthesis. [9][10][11][12][13] Likewise, Savithramma et al, 14 studied the antimicrobial activity of silver nanoparticles (Ag NPs) synthesized using medicinal plants were studied. Their results indicated that the Ag NPs exhibited maximum inhibition on the growth of Pseudomonas and Rhizophus species.…”
Nowadays there is an imperative demand to build up reliable, sustainable, and ecofriendly protocols for manufacturing a large collection of metal and metal oxide nanoparticles. The green synthesis of those nanomaterials has gained considerable attention as a promising tool to obstruct the harmful effects of nanoparticles resulting from conservative synthesis approach. Plant extracts in particular have been extensively utilized for the preparation of metal nanoparticles with the aid of essential phytochemicals in plant extracts. This short review describes the importance of plants as green sources for synthesis of metal nanoparticles.
“…Metal nanoparticles have been extensively explored due to their diverse applications in the areas of catalysis, biosensing, medicine, drug delivery etc. [1,[4][5][6][7][8]. In particular, silver nanoparticles (AgNPs) have received close attention due to their unique physicochemical properties [9][10][11][12].…”
Green synthesis of silver nanoparticles (AgNPs) using plant extracts has emerged as a viable environment-friendly method. The aim of the study was to biosynthesize AgNPs using cauliflower (Brassica oleracea var. botrytis) waste extract and further test their potential applications in photocatalytic degradation of methylene blue (MB) dye and Hg 2+ biosensing. Optimum extract concentration, AgNO 3 concentration, pH and temperature required for biosynthesis of stable AgNPs were determined by UV-visible spectroscopy. FT-IR, XRD, SEM, TEM, SAED, XPS and BET analysis were performed for characterizing AgNPs. MB dye degradation using AgNPs was determined by analyzing the intensity of dye absorption maxima at 664 nm. Specificity and sensitivity of biosynthesized AgNPs for Hg 2+ ions were studied for assessing their biosensing abilities. Optimum conditions needed for biosynthesis of stable AgNPs were observed to be 3 ml extract, 0.5 mM AgNO 3 , pH 8.5 and microwave-assisted heating at 600 W for 5 min. FT-IR analysis showed that the extract contained necessary functional groups that facilitated biosynthesis of AgNPs. XRD, SEM, TEM, SAED, XPS results confirmed the formation of AgNPs. BET analysis showed that AgNPs had an average size of 35.08 nm and surface area of 19.22 m 2 /g. Maximum MB dye degradation percentage of 97.57% was obtained at 150 min without any significant silver leaching thereby, signifying notable photocatalytic property of AgNPs. Biosensing studies showed that AgNPs were specifically able to detect up to 0.1 mg/l Hg 2+ ions. In summary, cauliflower waste served as a useful source of reducing agents for biosynthesizing AgNPs with promising environmental applications.
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