Abstract

Biomass, as a source of lignocellulose, can be valorized into carbon micro/nanofibers for adsorbing greenhouse gas (GHGs) emissions, especially CO<inf>2</inf>. This article is derived from systematic evidence evaluation of published studies, presenting new, innovative, and systemic approaches to lignocellulose-based carbon micro/nanofiber studies. The review covers a general overview of carbon micro/nanofiber studies, mapping chronicles of the studies, carbon micro/nanofiber types for CO<inf>2</inf> uptake, carbon micro/nanofibers fabrication and characterization, obtained carbonaceous material activation and performances, regulatory frameworks, and sustainability. The published studies show that carbon fiber has been researched for GHG emissions adsorption since the 1950s, with an increasing trend of publication numbers. The trend of studies has commenced from activated carbon to nanocarbonaceous materials and their composites. The excellent performance of both micro/nano-sized carbon provides promising opportunities for absorbing CO<inf>2</inf> and other GHGs, such as NO<inf>2</inf> and CH<inf>4</inf>, facilitating decarbonization. Several types of carbonaceous activation processes and modifications were utilized to enhance the performances of the resultant biochars, especially in surface materials, CO<inf>2</inf> adsorption capacity, and CO<inf>2</inf> selectivity. Proposed mechanisms for the absorption of CO<inf>2</inf> by activated carbonaceous materials through physisorption and chemisorption were also observed. To date, regulatory frameworks on the use of activated carbon for CO<inf>2</inf> capture are still rarely found, but biochar has been mainstreamed and regulated internationally for CO<inf>2</inf> removal. Other regulations have been enacted but have not yet internationally harmonized, mostly focusing on the terminology of carbon nanotubes, characterization, general applications, labelling, packaging, transportation, and the effects of toxicity on health. This study also proposed the sustainability aspects and performance indicators that can be used for circular economy application with an ultimate goal of climate change mitigation through GHG reduction. Besides the regulatory framework, elements of the business model and sustainability were proposed in the circular economy framework of the fibers. By scoping carbon micro/nanofibers studies, it is shown with obvious evidence that carbon micro/nanofibers and their composites have the potential for CO<inf>2</inf> adsorption and removal, leading to the acceleration of the decarbonization process that is in line with the Paris Agreement, especially in applying innovative CO<inf>2</inf> capture, storage, and utilization (CCSU) technologies.