Green synthesis and characterization of silver nanoparticles using Prunus persica L. (peach pomace) with natural deep eutectic solvent and plasma-liquid process

Biosynthesized and chemically synthesized Ag/TiO2 nanocomposites: Effect of reaction parameters on synthesis using watermelon rind extract and comparative analysis

This work synthesized Ag/TiO2 nanocomposite via an aqueous reduction method using a green and chemical reducing agent. Citrullus lanatus (watermelon) rind extract (WMRE) and sodium borohydride (NaBH4) were used as the reducing agents during green synthesis and chemical synthesis, respectively. During green synthesis, a pH of 12, a reaction time of 45 min, and an operating temperature of 100 °C yielded the best visible light activity. The biosynthesized and chemically-synthesized Ag/TiO2 were compared using UV-Vis spectroscopy, X-ray fluorescence spectroscopy (XRF), X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive spectroscopy-scanning electron microscopy (EDS-SEM) and transmission electron microscopy (TEM). Synthesis using WMRE yielded spherical Ag nanoparticles modified on the surface of TiO2 nanoparticles. The Ag nanoparticles had enhanced monodispersity with an average diameter of 7.48 ± 4.06 nm. Therefore, the developed WMRE green synthesis method provides a simple, less chemical-intensive, and effective alternative to chemical synthesis.

Green Synthesis, Characterization and Application of Silver Nanoparticles Using Bioflocculant: A Review

Nanotechnology has emerged as an effective means of removing contaminants from water. Traditional techniques for producing nanoparticles, such as physical methods (condensation and evaporation) and chemical methods (oxidation and reduction), have demonstrated high efficiency. However, these methods come with certain drawbacks, including the significant energy requirement and the use of costly and hazardous chemicals that may cause nanoparticles to adhere to surfaces. To address these limitations, researchers are actively developing alternative procedures that are cost-effective, environmentally safe, and user-friendly. One promising approach involves biological synthesis, which utilizes plants or microorganisms as reducing and capping agents. This review discusses various methods of nanoparticle synthesis, with a focus on biological synthesis using naturally occurring bioflocculants from microorganisms. Bioflocculants offer several advantages, including harmlessness, biodegradability, and minimal secondary pollution. Furthermore, the review covers the characterization of synthesized nanoparticles, their antimicrobial activity, and cytotoxicity. Additionally, it explores the utilization of these NPs in water purification and dye removal processes.

From nature to nanomedicine: bioengineered metallic nanoparticles bridge the gap for medical applications

The escalating global challenge of antimicrobial resistance demands innovative approaches. This review delves into the current status and future prospects of bioengineered metallic nanoparticles derived from natural sources as potent antimicrobial agents. The unique attributes of metallic nanoparticles and the abundance of natural resources have sparked a burgeoning field of research in combating microbial infections. A systematic review of the literature was conducted, encompassing a wide range of studies investigating the synthesis, characterization, and antimicrobial mechanisms of bioengineered metallic nanoparticles. Databases such as PubMed, Scopus, Web of Science, ScienceDirect, Springer, Taylor & Francis online and OpenAthen were extensively searched to compile a comprehensive overview of the topic. The synthesis methods, including green and sustainable approaches, were examined, as were the diverse biological sources used in nanoparticle fabrication. The amalgamation of metallic nanoparticles and natural products has yielded promising antimicrobial agents. Their multifaceted mechanisms, including membrane disruption, oxidative stress induction, and enzyme inhibition, render them effective against various pathogens, including drug-resistant strains. Moreover, the potential for targeted drug delivery systems using these nanoparticles has opened new avenues for personalized medicine. Bioengineered metallic nanoparticles derived from natural sources represent a dynamic frontier in the battle against microbial infections. The current status of research underscores their remarkable antimicrobial efficacy and multifaceted mechanisms of action. Future prospects are bright, with opportunities for scalability and cost-effectiveness through sustainable synthesis methods. However, addressing toxicity, regulatory hurdles, and environmental considerations remains crucial. In conclusion, this review highlights the evolving landscape of bioengineered metallic nanoparticles, offering valuable insights into their current status and their potential to revolutionize antimicrobial therapy in the future.

Synthesis of Kaolin-Supported Nickel Oxide Composites for the Catalytic Oxidative Degradation of Methylene Blue Dye

Organic dye contamination of water is a contributing factor to environmental pollution and has a negative impact on aquatic ecology. In this study, unsupported NiO and kaolin-supported NiO composites were synthesized by a one-step wet impregnation-precipitation method through the precipitation of nickel hydroxide onto locally accessible, inexpensive, and easily treated kaolin surfaces by using sodium hydroxide as a precipitating agent. The product was calcined at 500 °C and used for the catalytic oxidative degradation of methylene blue (MB) dye in an aqueous solution. The morphology, structure, and interactions of the synthesized materials were explored by SEM, XRD, and FT-IR spectroscopy. The characterization results revealed the fabrication and the growth of NiO on the kaolin surface. To determine the catalytic oxidative degradation performance of the catalyst, many experiments have been performed using the MB dye as a model dye. The catalytic degradation tests confirmed the importance of NiO and the high catalytic activity of the synthesized NiO/kaolin composite toward MB dye degradation. The oxidative degradation results showed that the optimized precursor amount on the kaolin surface could efficiently enhance the removal of MB dye. The kinetic investigation of the catalytic degradation of MB dye fitted the pseudo-first-order kinetic model. High removal efficiency was observed after eight reuse cycles, proving the exceptional stability and reusability of the composite. The catalytic process also proceeded with a low activation energy of 30.5 kJ/mol. In conclusion, the kaolin-supported NiO composite was established to be a favorable catalyst to degrade a model dye (MB) from an aqueous solution in the presence of inexpensive and easily available NaOCl with a catalytic efficiency of the material higher than 99% of the 20.3 mg catalyst within 6 min with an apparent rate constant, kapp, higher than 0.44625 min-1, which is far better than that of the unsupported catalyst with a kapp of 0.0926 min-1 at 10 mg dose in 20 min.

Green Synthesis of Gold Nanoparticles Using Peach Extract Incorporated in Graphene for the Electrochemical Determination of Antioxidant Butylated Hydroxyanisole in Food Matrices

Butylated hydroxyanisole (BHA) is a synthetic phenolic antioxidant widely used in various food matrices to prevent oxidative rancidity. However, its presence has been associated with liver damage and carcinogenesis in animals. Thus, an electrochemical sensor was built using a composite of gold nanoparticles synthesized in peach extract (Prunus persica (L.) Batsch) and graphene. Peach extract served as a reducing and stabilizing agent for gold nanoparticles, as a dispersing agent for graphene, and as a film former to immobilize the composite on the surface of a glassy carbon electrode. The gold nanoparticles were characterized using spectroscopic and microscopic techniques, and the electrodes were electrochemically characterized using electrochemical impedance spectroscopy and cyclic voltammetry. The sensor provided higher current responses and lower charge transfer resistances compared to the unmodified glassy carbon electrode. Under the established optimized working conditions (0.1 mol L-1 Britton-Robinson buffer, pH 4.0, and differential pulse voltammetry), the calibration curve exhibited a linear range from 0.2 to 9.8 µmol L-1, with a detection limit of 70 nmol L-1. The proposed sensor represented a sensitive and practical analytical tool for the accurate determination of BHA in mayonnaise samples.

Kaolin-Supported Silver Nanoparticles as an Effective Catalyst for the Removal of Methylene Blue Dye from Aqueous Solutions

Water contamination by organic dyes has become a reason for severe environmental pollution and has been threatening the aquatic ecosystem. In this study, kaolin-supported silver nanoparticle (Ag-NP) composites were synthesized by a facile two-step adsorption-reduction method through the reduction of silver ions adsorbed onto locally available, inexpensive, and easily pretreated kaolin surfaces by using sodium borohydride (NaBH₄) for the catalytic degradation of methylene blue (MB) dye in aqueous solution. The morphology, structure, surface area, and interaction of the synthesized materials were investigated by scanning electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller, and Fourier transform infrared spectroscopy, respectively. Characterization results showed the successful growth of Ag-NPs on the kaolin surface. To understand the catalytic degradation performance of the catalyst, batch experiments were carried out using MB dye as a model dye. The catalytic reduction tests confirmed the importance of Ag-NPs and the high catalytic activities of the synthesized Ag-NPs/kaolin composite toward MB dye reduction. The degradation results indicated that the increased Ag-NP content on the kaolin surface through repeating cycles could effectively enhance the removal of MB dye from an aqueous solution. The kinetic analysis of the MB dye degradation of the catalyst has fitted the pseudo-first-order kinetic model. More than 97% removal efficiency was still present after five reuse cycles, demonstrating exceptional stability and reusability of the composite. In conclusion, the Ag-NPs supported kaolin (Ag-NPs/kaolin) composite was found to be a promising catalyst for the excellent catalytic activity to reduce a model dye MB from the aqueous solution in the presence of NaBH₄ with catalytic efficiency higher than 97% and a reduction rate constant, k _red, higher than 0.86 min^-1.

From Biorefinery to Food Product Design: Peach (Prunus persica) By-Products Deserve Attention

There is an increasing demand for functional foods to attend the consumers preference for products with health benefits. Peach (Prunus persica), from Rosaceae family, is a worldwide well-known fruit, and its processing generates large amounts of by-products, consisting of peel, stone (seed shell + seed), and pomace, which represent about 10% of the annual global production, an equivalent of 2.4 million tons. Some studies have already evaluated the bioactive compounds from peach by-products, although, the few available reviews do not consider peach by-products as valuable materials for product design methodology. Thereby, a novelty of this review is related to the use of these mostly unexplored by-products as alternative sources of valuable components, encouraging the circular bioeconomy approach by designing new food products. Besides, this review presents recent peach production data, compiles briefly the extraction methods for the recovery of lipids, proteins, phenolics, and fiber from peach by-products, and also shows in vivo study reports on anti-inflammatory, anti-obesity, and anti-cerebral ischemia activities associated with peach components and by-product. Therefore, different proposals to recover bioactive fractions from peach by-products are provided, for further studies on food-product design.