An overview of biogas upgrading via pressure swing adsorption: Navigating through bibliometric insights towards a conceptual framework and future research pathways

Biogas upgrading is an attractive solution to mitigate greenhouse gas emissions, presenting an alternative renewable source of energy to meet the SDG 13 and SDG 7 of the UN charters. Pressure swing adsorption (PSA) distinguishes itself from water scrubbing, amine absorption, and cryogenic separation methods in CO₂ separation from biogas mixtures by offering lower energy consumption, enhanced purity, and immunity to corrosion issues. This review provides a comprehensive analysis of the current development status, research trends, and emerging frontiers of PSA in biogas upgrading. Leveraging the bibliometric analysis capabilities of VOSViewer software, a total of 127 articles related to CO₂ separation from CH₄ streams using PSA technology were scrutinized for specific characteristics, including publication year, authors, institutions, countries, references, and keywords. Co-citation analysis, complemented by content analysis of highly cited articles, identifies four primary research streams: i) modifications to existing PSA system designs, ii) development of novel adsorbents, iii) exploration of composite materials and diverse bed configurations, and iv) simulation studies for comprehensive mass and energy analyses. This study unveils current trends, global collaboration patterns, foundational knowledge, research hotspots, and emerging frontiers in the field of CO₂ separation from CH₄ streams using PSA technology.