Recent advancements and future pathways in biogas purification technologies for a circular economy

Abstract

Biogas, produced through the anaerobic digestion of organic matter, serves as a vital renewable energy source, mitigating greenhouse gas emissions and promoting energy independence. This review critically analyzes the current landscape of biogas upgrading technologies, categorizing them into physical, chemical, and biological methods. Also, the review evaluates and establishes techniques, including water scrubbing, pressure swing adsorption (PSA), chemical absorption, membrane separation, and cryogenic distillation, as well as emerging biological methods such as biofiltration. Evidently, the review highlights membrane separation as a technologically efficient, rapidly growing commercial alternative that has garnered significant recent research interest. This is thanks to its modularity, low energy intensity, and recent advances in materials, such as mixed-matrix membranes, which enhance selectivity across various scales. Though no single method obtained a generally accepted optimum, findings reveal that integration of hybrid configurations such as biofiltration coupled with pressure swing adsorption and smart control strategies is essential to optimize methane recovery and cost-effectiveness. However, these advancements remain limited by a lack of field-scale data and the need for degradation-resistant materials. Future research should focus on leveraging artificial intelligence, developing advanced materials, and designing hybrid systems to optimize biogas purification and support a sustainable circular bioeconomy.