Nanoparticles continue to remain an important and diverse class of materials with applications in all major areas of the economy, including manufacturing, medicine, and energy, with new products finding their way to market [1]. The main classes of nanoparticles utilized in products include carbon-based (nanotubes and fullerenes), metallic (including gold, silver, iron, and copper), metal oxide (MgO, ZnO, TiO2, CeO2, SiO2 among others), and quantum dots [2].
The synthesis and analysis of nanoparticles have become crucial in various scientific fields due to their unique properties and diverse applications. Among the various nanoparticles, magnesium oxide (MgO) has gained significant attention for its roles in catalysis, antibacterial activity, and as an additive in refractory materials [3]. However, traditional methods of synthesizing MgO nanoparticles often involve hazardous chemicals and high energy consumption. This necessitates the exploration of greener synthesis routes, such as bio-synthesis, which utilizes natural resources and offers a more sustainable and environmentally friendly approach [4].
Bio-synthesis of nanoparticles leverages plant extracts, which contain a variety of phytochemicals such as flavonoids, alkaloids, and tannins, acting as reducing and stabilizing agents [5]. In this study, the focus is on the bio-synthesis of MgO nanoparticles mediated by the leaves of Rubber (Hevea brasiliensis), Awolowo (Chromolaena odorata), and Oil palm (Elaeis guineensis). These plants are chosen due to their rich phytochemical content and abundance in tropical regions, making them ideal candidates for green synthesis.
The Rubber tree (Hevea brasiliensis) are primarily known for latex production, but the leaves contain various bioactive compounds [6]. Similarly, Awolowo (Chromolaena odorata), a medicinal plant, is rich in secondary metabolites with potential applications in nanoparticles synthesis [10]. Oil palm (Elaeis guineensis), primarily cultivated for oil production, has leaves that are often considered waste but possess valuable phytochemicals [8]. By utilizing these plant extracts, the synthesis of MgO nanoparticles can be achieved in an eco-friendly manner.
The analysis of these bio-synthesized nanoparticles is critical to understanding their properties and potential applications. Some of the most common methods for nanoparticles analysis include microscopy, spectroscopy, elemental characterization, and particle sizing methods. According to Ikhouria et al. [7], these techniques provide comprehensive information about the nanoparticles’ size, shape, morphology, elemental and structural characteristics, and particle sizes.
Microscopy methods such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are essential for visualizing the sample’s size, shape, and morphology [10]. SEM provides insights into particle sizes, morphology, and the degree of agglomeration or networking [11], while TEM reveals the internal structure and crystallinity of the particles[12]. Spectroscopy methods like Raman spectroscopy, UV/Visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR) are used to analyze the nanoparticles’ electronic structure, surface chemistry, and chemical groups [13]. Raman spectroscopy is particularly useful for determining sizes for very small particles and identifying order/disorder within the structure [14]. Elemental characterization techniques, including the use of X-ray fluorescence Spectroscopy provide detailed information about the elemental composition of the nanoparticles [15]. Particle sizing methods such as dynamic light scattering yield information about the size and shape of the particles [16].
Thermal analysis methods, which measure the properties of the sample as a result of changes in temperature or heat flow, are often used to provide quick information on nanoparticles in manufacturing or laboratory settings [17]. Techniques such as thermogravimetric analysis (TGA) and differential thermal analysis (DTA) are critical for understanding the thermal stability and composition of bio-synthesized nanoparticles. TGA measures the amount and rate of weight change in a material as a function of temperature or time, offering insights into decomposition patterns [18]. DTA complements TGA by detecting exothermic and endothermic transitions, providing a deeper understanding of the thermal properties and stability of the synthesized nanoparticles [19].
The purity and composition of nanoparticles is vital for both their practical applications and for maintaining quality control in manufacturing processes [20]. The wide array of production methods introduces significant challenges, particularly regarding potential impurities or residues that can influence nanoparticles properties. For instance, nanoparticles synthesized through solution-based methods, which involves precipitation from chemical reactions. By-products or residues may become trapped within or adsorbed onto the nanoparticles [21]. In applications such as drug delivery, bio-reduction precipitation technique can encapsulate components of the suspension solution within the nanoparticles themselves
Thermogravimetric analysis (TGA) serves as a crucial technique for assessing nanoparticles composition. TGA measures the sample's weight change as it is heated, offering insights into thermal stability and decomposition patterns [17–22]. This method allows researchers to quantify the mass percentage of specific components present in the nanoparticles mixture, aiding in the identification and quantification of impurities or encapsulated materials [23]. However, a primary challenge in TGA analysis of nanoparticles lies in isolating them from their surrounding solution or matrix. Techniques like centrifugation or other separation methods are often necessary to extract nanoparticles accurately for analysis[24]. Once isolated, heating the nanoparticles sample reveals temperature transitions indicative of oxidation, which are compared to those of pure components to determine chemical composition [25]. TGA plays a pivotal role in nanoparticles analysis by providing essential information on purity, composition, and thermal properties. This capability is crucial for understanding and optimizing nanoparticles production processes, ensuring their suitability for diverse applications in fields ranging from medicine to materials science [26]. This research aims to explore the thermal behavior of MgO nanoparticles synthesized using the extracts of Rubber, Awolowo, and Oil palm leaves. Through a comprehensive TGA/DTA analysis, this study seeks to provide insights into the thermal stability, composition, and potential applications of these bio-synthesized nanoparticles and contribute to the growing body of knowledge on green synthesis methods and their applications in nanotechnology.