Plant‐supported silver nanoparticles: Efficient, economically viable and easily recoverable catalyst for the reduction of organic pollutants

Abstract

Ginger rhizome powder was used for the synthesis of supported metallic nanoparticle catalysts. A simple and novel adsorption method was used for the synthesis of silver nanoparticles loaded on ginger powder (Ag/GP), copper on ginger powder (Cu/GP) and nickel on ginger powder (Ni/GP). Among these, Ag/GP showed selective reduction of methyl orange and was used for further reactions. The prepared nanomaterials were characterized through X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, fourier transform infrared spectroscopy and energy-dispersive X-ray spectroscopy. The prepared Ag/GP catalyst was employed in the catalytic reduction of 4-nitrophenol (4-NP), 2-nitrophenol (2-NP), rhodamine B, methyl red and congo red. Ag/GP showed excellent catalytic reduction activity, the rate constants being 1.26 × 10 −3 and 2.38 × 10 −3 s −1 for 2-NP and 4-NP, respectively.The turnover frequency reached 1.06 min −1 for 2-NP and 1.16 min −1 for 4-NP when using the Ag/GP catalyst. The prepared Ag/GP catalyst demonstrated outstanding activity for the degradation of a mixed solution of dyes. Also, stability and reusability of the prepared catalyst were investigated, which showed outstanding reusability up to five times and was stable up to five days. KEYWORDS dye reduction, green synthesis, pseudo first-order kinetic, reusability and stability of catalyst, turnover frequency

Characterizations and analysis of the antioxidant, antimicrobial, and dye reduction ability of green synthesized silver nanoparticles

“…EDS pattern of AgNPs is presented in Figure 4. The strong peak at EDS pattern around 3 keV is because of the binding energies of Ag [41,61]. Results obtained coincide with the peak value obtained for AgNPs synthesized by using Coleus aromaticus [62].…”

“…Many methods are used to treat sewage, such as photocatalysis, adsorption, catalysis, etc. Most industries like textiles, cosmetics, and plastics are manufacturing various synthetic dyes and using them for the colouring of their products [41]. For example, dyes with azo groups like MO are highly toxic and cancercausing, resulting in a severe threat to aquatic organisms.…”

Plant Extract Induced Biogenic Preparation of Silver Nanoparticles and Their Potential as Catalyst for Degradation of Toxic Dyes

“…The best way to reduce toxic effects of these dyes is to convert them into less toxic products by using NaBH 4 as reductant. Thus, these products are alternatively reduced to further non-toxic products [46]. However, the reduction of dyes by BH 4 −1 ions is a thermodynamically favorable process.…”

“…Monitoring of reaction was continued until the change in absorbance of reaction mixture became constant. Due to excessive use of NaBH 4 as compared to CR (NaBH 4 /CR ≥ 100), the kinetic aspect of reduction reactions was explained by pseudo first order [ln(A t /A o ) against time] [46]. CR was not reduced immediately after the addition of catalyst in the reaction mixture in the presence of NaBH 4 reductant.…”

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“…A part from its therapeutic action, the ginger rhizome powder can be formulated into silver nanoparticles (which showed the best result than copper and nickel) where it can be used as a recoverable and reusable catalyst for the reductive hydrogenation of nitro-phenols and degradation of organic pollutants (azo dyes) that can cause harm to the surroundings 60 . Several research works of plant-derived nano-vesicles (like ginger-derived nanoparticles) was considered as a novel form of nano-medicine in aspects of anti-cancer in ulcercolitis 61 anti-inflammation, modulating commensal microbiota by promoting Lactobacillus rhamnosus (LGG) growth in the gut 62 tissue regeneration in case of alcohol-induced liver damage 63 and inhibiting Porphyromonas gingivalis in the oral cavity 64 .…”