About this Research Topic
Due to the increasing CO2 accumulation in the atmosphere and the associated environmental impact, the development of effective capture systems is considered an urgent priority. Of the various techniques, adsorption presents particular prominence. This is mainly due to the low energy consumption, cyclability, fast kinetics, and the fact that it is environmentally friendly. Currently, a variety of low-medium and high-temperature solid adsorbents are being investigated, including siliceous and carbonaceous materials, clays, alumina, metal-organic frameworks (MOFs), zeolites, porous polymers, alloy-based dry sorbents, etc. Intense efforts are focused on these materials chemical modification, including surface functionalization, pore tuning, hybrids formation, ion exchange, organic-inorganic composites synthesis, etc. This focus is to enhance their capture performance and selectivity at various conditions of pressure and temperature, and for a wide range of mixture characteristics including gas streams with low CO2 content (5-10%), along with a broad applicability, including energy exchangeable multi-stage CO2 capture technology schemes.
The materials that are being investigated for CO2 adsorption need to be optimized to meet the specifications required for large-scale capture applications. The optimal adsorbents should exhibit high capacity, selectivity, chemical and thermal stability, fast kinetics, sustainable performance for many cycles, low energy consumption, low manufacturing cost, and resistance to attrition and erosion. Intense research efforts are underway as to grant materials with these highly sought-after qualities. To this end, adsorbents are being functionalized by post-synthesis chemical grafting or impregnation with moieties, that can enhance uptake capacity and selectivity. Also, hybrids of combinations of adsorbents or adsorbent-support configurations are being prepared as to enhance stability, pore functionalities are being modified, molecules with CO2 binding function are getting involved in situ in the synthesis sols of the adsorbents, MOFs with high-density open metal sites are produced, K2CO3-promoted hydrotalcites and Na2O-promoted aluminas are modified to limit structural transformations during adsorption at HT etc. These modification efforts, which are experimental as well as simulation-based, will be the focus of the current Research Topic collection.
The current Research Topic collection will focus on chemical modification of adsorbents to enhance their performance for CO2 capture. Original research, as well as review articles of experimental and/or modeling contributions, are welcome, including – yet not limited - to the below topics:
• Amine grafting of adsorbents
• Pore tuning of materials including hierarchical porosity formation
• Alteration of pore functionalities in MOFs, COFs, and related materials
• Formation of hybrid structures, such as MOFs and zeolites with graphene oxide, CNTs, clays, etc. as to achieve multifunctionality
• Modification of adsorbents for efficient capture of CO2 from very low concentration mixtures
• Modification of adsorbents to enhance their chemical stability in the presence of reactive species such as H2S
• Modification of adsorbents to increase cyclability, and reduce energy of regeneration.
Keywords: CO2, Adsorption, Porous Materials, Functionalization, Carbon Capture, Gas Separation
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.