Persea americanaseed extract mediated gold nanoparticles for mercury(ii)/iron(iii) sensing, 4-nitrophenol reduction, and organic dye degradation

Abstract

In this work, Persea americana (Avocado) seed extract mediated systematically optimized synthesis has been employed for the formation of small sized gold nanoparticles (Av-AuNPs) at different pH values. The size, shape and crystallinity of the as-prepared AuNPs have been studied using transmission electron microscopy and X-ray diffraction. The nanoparticles were found to be selective towards mercury(II) upon the prior or subsequent addition of iron(III), revealing a blue shift and an enhancement of the characteristic surface plasmon resonance (at 519 nm). Similar absorbance based selectivity has been observed towards Fe(III) in the presence of Hg(II). The high sensitivity and selectivity of Av-AuNPs towards Hg(II) and Fe(III) has been attributed to the formation of core-shell structures. From the UV-visible spectroscopic measurements, the limits of detection for Hg(II) and Fe(III) are found to be 50 nM and 30 nM (around one order of magnitude less than the Environment Protection Agency limit of 0.7 mM for Fe(III) in drinking water) respectively, with an excellent linear dependence over a wide range of concentrations. Additionally, as-prepared Av-AuNPs have been demonstrated to be efficient in the reduction of organic pollutant 4-nitrophenol to 4-aminophenol and degradation of some organic dyes, such as Methylene Blue, Direct blue, Rhodamine 6G, Bromophenol blue and methyl orange. The use of the proposed Av-AuNPs for sensing and green catalysis can form the basis of high-performance analytical assays, effective multiplexed intracellular sensors, and sophisticated and sustainable probes/ catalysts. View Article Online a P.S. ¼ present study. Scheme 1 Possible mechanism for Hg(II) and Fe(III) sensing using Av-AuNPs. Fig. 5 Absorbance spectra for (a) the sensing of Hg(II)using Av-AuNPs-Fe(III) and (b) sensing of Fe(III) using Av-AuNPs-Hg(II); the linear fitting of concentration vs. absorbance intensity of (c) Hg(II) (R 2 ¼ 0.997) and (d) Fe(II) sensing (R 2 ¼ 0.999).39838 | RSC Adv., 2019,9,[39834][39835][39836][39837][39838][39839][39840][39841][39842] This journal is

Honeybee pollen assisted biosynthesis of nanogold and its application as catalyst in reduction of 4-nitrophenol

“…Among all nitrophenolic compounds, 4-NP is an important raw material used in various chemical industries (dye, electronics, textiles, food, medicine, agrochemical) and is stable in aqueous media for an extended period of time. Its excessive use poses several environmental and health hazards including shortness of breath, nausea, cianosis, methemoglobinemia, fervescence, liver and kidney damage, dizziness, headaches, etc., to humans [27,28]. Therefore, removal of 4-NP from the environment is of great interest and a challenging task for the J o u r n a l P r e -p r o o f scientist.…”

Solution‐based deposition of nano‐embossed metal electrodes on cotton fabrics for wearable heaters and supercapacitors

“…The XRD pattern of commercial cotton is corresponded well with the results of other studies, corresponding to the crystallized cellulose fiber in the cotton sheet. After deposition of the Au NP seeds, the Au NP‐cotton showed weak peaks at 2 θ = 38.4°, 44.6°, 64.8°, and 77.8° with a crystallinity of 50.4%, corresponding to the face‐centered cubic structure of the Au crystal 52 . Similarly, the XRD pattern of the Au‐cotton electrode showed four distinct peaks at 38.4°, 44.6°, 64.8°, 77.8°, and 81.9° with a crystallinity of 82.9%.…”

Reduction of 4-nitrophenol using green-fabricated metal nanoparticles

“…35 The particle size of metal nanoparticles plays a significant role in the removal of 4-nitrophenol. These particle size measurements have been achieved using dynamic light scattering 27 -based particle size analyzers and high-resolution transmission electron microscopy. 37 As is known, the surface charge and functional groups present on the catalyst can improve the adsorption of the organic pollutant, followed by the fast catalyst reduction of 4-NP, which have been obtained from zeta potential and Fourier transform infrared spectroscopy (FT-IR) studies, respectively.…”

“…Also, several green reducing agents, such as ascorbic acid, 24 formic acid, 23 tetramethyl disiloxane, 25 plant or seed extracts, and microorganisms, 26 have been studied. 19,[27][28][29] The purpose of this review is to present the scientic advances in the green synthesis of noble metal nanoparticles and their application in the reduction of 4-nitrophenol in aqueous media, clearly explaining the reaction mechanisms of both metal nanoparticle synthesis and 4-NP reduction.…”

“…Also, several green reducing agents, such as ascorbic acid, 24 formic acid, 23 tetramethyl disiloxane, 25 plant or seed extracts, and microorganisms, 26 have been studied. 19,27–29…”