Title : Synthesis and characterization of green nano fertilizer using banana peels, watermelon rinds and aloe vera gel extract
Abstract:
Traditional fertilizer production relies on non-renewable resources and energy-intensive methods that negatively impact the environment. Repurposing agricultural waste as feedstock offers a sustainable and eco-friendly route for developing green nano-fertilizers. In this study, a green nano-fertilizer was synthesized by combining banana peel extract (BPE), watermelon rind extract (WRE), and aloe vera gel extract (ALvE). These extracts served a dual role, supplying nutrients and acting as natural reducing and capping agents. The green nano-fertilizer was prepared by blending the peels or gel with distilled water (1:2 w/v). The BPE and WRE slurry were subsequently alkalized with potassium hydroxide and boiled for 30 min. BPE and WRE were combined in defined ratios (50:50, 75:25, and 25:75, v/v) and ALvE (5, 10, and15 mL) was added dropwise into the mixture at 70 °C with constant stirring, resulting in nine formulations. The resulting formulations were characterized using Ultraviolet-Visible (UV-Vis) spectroscopy, pH and Electrical Conductivity (EC) measurements, Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction (SAED) and Scanning Electron Microscopy-Energy-Dispersive X-ray Spectroscopy (SEM-EDS). The UV-Vis spectroscopy revealed that the characteristic absorption bands of each plant extract were retained in the composite material, with slightly bathochromic and hypsochromic shifts observed. This indicates the successful formation of noncovalent composite derived from BPE, WRE and ALvE. The BPE and WRE, along with their composites produced strongly alkaline formulations (pH 9.78–12.26) and higher EC (7.12–12.26 mS cm-¹), while ALvE exhibited a mildly acidic pH of 5.2 and lower EC of 0.53 mS cm-¹. TEM analysis showed nanosized particles with average particle size < 100 nm. SEM-EDS confirmed the presence of essential macro-nutrients (N, P, K), and the 75%BPE+25%WRE+5 mL ALvE formulation contained all three macronutrients (NPK). The present study presents an efficient, green-synthesis route for synthesizing tunable NPK nano-fertilizer using plant extract from plant-based waste materials.
Keywords: Green Nano-Fertilizer, Plant Extracts, Banana Peel, Watermelon Rind, Aloe Vera Gel Extract, UV-Vis, TEM, SEM-EDS.
