Green nanotechnology: silver nanoparticle synthesis via brewed coffee grounds extract

Silver nanoparticles (AgNPs) are increasingly valued for their diverse applications, but traditional preparation methods often involve toxic chemicals, necessitating environmentally friendly alternatives. This study explores a sustainable alternative: the green synthesis of AgNPs using brewed coffee grounds (BCG). BCG, a readily available agricultural byproduct rich in phenolic compounds, particularly chlorogenic acid, acts as a reducing and capping agent, facilitating the sustainable and efficient reduction of silver ions to AgNPs. The preparation process was optimized by varying the pH (6 and 8), impacting nanoparticle size and morphology. Characterizations using UV-Vis spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy confirmed the formation of crystalline AgNPs with a face-centered cubic structure. The results demonstrate that alkaline conditions (pH 8) yielded smaller, more uniformly distributed AgNPs with superior stability than those prepared at pH 6. This green synthesis method offers a promising approach to producing AgNPs while promoting sustainability and resource efficiency. The study highlights the potential for waste valorization and the development of eco-friendly nanomaterials for various applications.