The authors examine several groups of nanoparticles, including metallic nanoparticles such as iron, nickel, and silver, metal oxides, and carbon-based nanomaterials. Across the studies reviewed, nanoparticles were found to influence anaerobic digestion through several mechanisms, including stimulating microbial activity, improving enzymatic activity, and facilitating electron transfer between microorganisms involved in the digestion process.

 

Importantly, the effectiveness of nanoparticle addition depends strongly on factors such as the type of material used, particle size, concentration, and dosing strategy. The review shows that these factors can affect both overall biogas production and methane yield. In some cases, nanoparticles can also shorten the time required for biogas production or improve the stability of the digestion process. However, higher concentrations do not necessarily result in better performance and can instead inhibit microbial activity.