Biosynthesis of NiO nanoparticles for photodegradation of free cyanide solutions under ultraviolet light

Abstract

In this study, we used an environmentally friendly green method to synthesize NiO nanoparticles (NiO NPs) with an extract from Persea americana seeds for use as photocatalysts in the photodegradation of free cyanide (FCN). The characteristics of the NiO NPs were determined by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), ultraviolet-visible (UV-Vis) analysis, and Fourier transform infrared (FTIR) spectroscopy. The XRD results indicated a cubic-type structure with space group Fm m 3 , No. ( 225). Morphological analysis conducted using TEM showed that the NiO NPs had rhombohedral and spherical shapes with slight agglomeration. The particle size calculated based on the TEM results was 11 nm. EDS analysis confirmed the elemental constituents of the samples with Ni and O atoms. The phase purity and chemical bonds in NiO were confirmed using FTIR spectroscopy analysis. UV-Vis analysis indicated that the NiO NPs samples exhibited good optical properties with a well-defined peak at 338.9 nm. The energy band gap E g obtained for NiO NPs based on the optical analyses was 3.75 eV. The NiO NPs performed well as a photocatalyst under UV light during the photodegradation of FCN, where the maximum photocatalytic oxidation efficiency was 84% after irradiation for 30 min. The FCN photodegradation mechanism was elucidated based on the photocatalytic oxidation of compounds by oxygen with semiconductors.

Investigation of structural and optical properties of biosynthesized Zincite (ZnO) nanoparticles (NPs) via an aqueous extract of Rosmarinus officinalis (rosemary) leaves

“…The bulk of nanoparticles appeared to be polycrystalline. From these results, it was established that the Bunsenite is generally cubically structured [4,12,14].…”

“…The absorption band 1387 cm À1 was assigned the C = O, CH 3 and C = C aromatic functional groups associated with various bioactive compounds in the Rosemary leaves extracts. The weak bands at 1645 and 3468 cm À1 may well be attributed to moisture absorbed/adsorbed on to the surface of the nanoparticles and the (OH) hydroxyl groups, respectively [4,11,13].…”

“…Metallic oxide nanoparticles, specifically nano-scale NiO has attracted considerable attention in recent decades due to its high chemical stability, electrocatalysis, electron transfer capabilities, and supercapacitance properties. Bunsenite is an environmentally friendly material, a p-type semiconductor metal oxide with a wide bandgap ranging from 3.6 to 4.0 eV [3,4]. In terms of synthesis, several chemical and physical methods are commonly used.…”

“…Consequently, an alternative and environmentally benign synthesis route that adheres to the green chemistry approach involving phytoexudes or extracts is becoming a popular approach for nanoparticles synthesis and advocated for its rapidity, simplicity, minimized energy intensity thus reduced synthesis costs with minimum waste generation to produce the desired metal oxides NPs [8][9][10]. Plant extracts such as those from Callistemon viminalis (Weeping bottlebrush) Sageretia thea (Osbeck), Aspalathus linearis (Rooibos), Agathosma betulina (Buchu), Aegle marmelos L. (Bael) have been used as capping, reducing, chelating, and stabilizing agents for NiO nanoparticles [4,[11][12][13][14] except leaves extract from Rosmarinus officinalis, commonly known as rosemary has not been reported in the literature as a viable source for the synthesis of Bunsenite to the best of our knowledge.…”

Phytogenic Generation of NiO Nanoparticles Using Stevia Leaf Extract and Evaluation of Their In-Vitro Antioxidant and Antimicrobial Properties

“…Moreover, a few of them were slightly agglomerated, which may be due to the large volume of heat produced in the annealing process. However, the small-sized particles were very reactive due to sharp edges, which contain a high surface-to-volume ratio (the higher portion of outward atoms) and less cohesive energy compared with bulk materials [27,28]. Furthermore, the particle size, shape, and distribution of the synthesized nanoparticles were determined using HR-TEM analysis and their lattice fringes were evaluated.…”