Production of High-Quality Biogas Using Recycled Trimetallic Nanoparticles from Electronic Waste

A plethora of nanoparticles (NPs) significantly enhanced the biogas production from organic waste anaerobic digestion upon their optimized addition to the reactors. In this study, trimetallic Sn–Mn–Fe.NPs, recovered from waste-printed circuit boards, were used to enhance the quality and productivity of the anaerobic digestion (AD) of cow manure as an organic substrate. This study aims to make the biogas production process more efficient and economically sustainable, taking into account the environmentally friendly nature of the AD process. The obtained nanoparticles were characterized using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD) techniques. Various concentrations (20, 50, and 100 mg/L) of the trimetallic Sn–Mn–Fe NPs were added to the biogas reactors, which were made of 1000-ml autoclave glass bottles to host the animal waste during the AD process. The pressure of the biogas produced was monitored daily for 45 days as retention time, and the volume of the produced biogas was calculated at a constant temperature (15 °C) and pressure (1.013 bar). Generally, NP-based reactors showed superiority in biogas production over blank reactors. Also, among the different concentrations, the best biogas-producing digester (RC2200) revealed the highest performance with a 113.6% enhancement in biogas production. In addition, it showed a significant increase of 231.2% in methane production.