The effectiveness of iron-based additives in enhancing methane and hydrogen production: a systematic review

The proper treatment of animal manure, sewage biosolids, agricultural by-products, and food waste is becoming increasingly vital due to environmental concerns. Hydrogen is currently regarded as a clean energy source with a high energy density, whereas methane has been utilized extensively. Using anaerobic digestion, biohydrogen and methane are produced. Alternative performance-influencing factors, such as metallic nanoparticles and process optimization, must be identified. Consequently, iron-based materials are inexpensive and effective; however, if the threshold is exceeded, the biological process may be inhibited. This review focuses on analyzing the most recent advancements in the biological process enhanced by iron-based materials, the current state of knowledge, identifying the gaps for future research, methods for studying microbial communities, and promising new materials. It was supplemented by a bibliographic analysis that evaluated the difficulties of large-scale facilities and emphasized the economic implications and strategies for recovering iron-based materials. This article discusses possible future directions for research.