Influence of zero-valent iron nanoparticles on anaerobic digestion of swine manure: effects on methane yield

• Published in: Environmental technology 2024-12, Vol.45 (27), p.5784-5793
• Main Authors: Yañez Palma, Rosimary, Córdova-Lizama, Alfredo Javier, Zepeda Pedreguera, Alejandro, Ruiz Espinoza, Juan Enrique
• Format: Article
• Language: English
• Subjects: Acetic acid; Anaerobes; Anaerobic digestion; Anaerobiosis; Animals; biochemical methane potential; biochemical pathways; Biological activity; Bioreactors; Chemical composition; Composition effects; Control systems; electron transfer; Electron transport; environmental technology; Iron; Iron - chemistry; Manure; Manures; Metal Nanoparticles - chemistry; Methane; Methane - chemistry; Methane - metabolism; methane production; Microbial activity; Microorganisms; Nanoparticles; Pig manure; Reactors; Swine; swine manure; Transportation systems; Volatile fatty acids; zero-valent iron nanoparticles
• ISSN: 0959-3330; 1479-487X; 1479-487X
• DOI: 10.1080/09593330.2024.2306798

This study evaluated the effect of zero-valent iron nanoparticles (NZVI) on the anaerobic digestion of swine manure. A wide range of doses of NZVI was evaluated (5, 10, 15, 20, 25, 50, and 100 mgFe°/gVS). The maximum methane yield of 0.4506 L/gVSremoved was obtained with the concentration of 10 mgFe°/gVS representing an increase of 58.99% than the control system with 0.2834 L/gVSremoved, indicating that Fe° improves the methanogenic activity. However, when using doses greater than 20 mgFe°/gVS, there were decreases in the methane yield of 34.4-47.98%. Also, to observe the effect of NZVI in anaerobes was evaluated the activity in the electron transport system (ETS), where the control reactor showed an activity of 31.91 μg INTred/gVS*h, while in reactors with NZVI showed values of 39.48 μg INTred/gVS*h (10 Fe°mg/gVS), observing a stimulation of Fe° in microbial activity. However, the dose of 100 mgFe°/gVS showed the greatest decrease in methane yield (0.1474 L/gVSremoved) and a reduction in ETS was observed by 8.5% compared to the control. The effect on the composition of the volatile fatty acids was observed, where the control system obtained a maximum production of acetic acid of 639 mg/L, which was exceeded with the dose of 10 mg Fe°/gVS by 215% and a decrease of 41.15% with the inhibitory concentration of 100 mg Fe°/gVS. As a result, higher doses of NZVI affect the metabolic activity of anaerobes as well as the acetoclastic pathway causing a decrease in the methane production.