Screening,preparation,and prototyping of metal–organic frameworks for adsorptive carbon capture under humid conditions

Adsorption-based carbon capture has been recognized as an attractive method for mitigating global warming.Metal–organic frameworks(MOFs)are promising candidate adsorbents for this purpose due to their high adsorption uptake and selectivity for carbon dioxide.However,in real-world applications,such as direct air capture,the presence of moisture in the feed gas may pose a grand challenge for CO_(2)adsorption in MOFs.This paper aims to address the issue of water–CO_(2)co-adsorption in MOFs and present screening criteria for selecting MOFs that preferentially adsorb CO_(2)under humid conditions.First,we uncover a comprehensive overview of CO_(2)–water co-adsorption characteristics of various MOFs.Then,the high-throughput screening methods are summarized.Both computational and experimental efforts have been dedicated to identify the promising MOFs for humid CO_(2)capture.According to the screening results and adsorption mechanism,the optimal preparation strategies are proposed tomodulate the effect of water on CO_(2)uptake in MOFs.Finally,current MOF-based CO_(2)capture prototypes are presented to evaluate their practical feasibility and performance.This work could offer valuable guidance for the development and application of MOFs for CO_(2)capture in the presence of water and inspire further research in this field.

Thermodynamic analysis on direct air capture for building air condition system:Balance between adsorbent and refrigerant

Direct air capture(DAC)is one of the most potential technologies to mitigate CO_(2) emission.Adsorption technol-ogy is recognized as a promising CO_(2) capture method in view of its desirable characteristics including reusability of adsorbents and low capital investment.To further improve thermal performance,evaporation/condensation heat of vapor compression refrigeration(VCR)cycle in air condition system of buildings is adopted for adsorp-tion/desorption process of DAC.Thermal performance of a 4-step temperature swing adsorption process(TSA)is analyzed at various adsorption/desorption temperatures by using different adsorbents.Analysis on Coefficient of Performance(COP)of VCR cycle is also conducted in search for a balance between adsorbent and refrigerant.Taking both real working capacity and COP into consideration,Mg-MOF-74&R134a is the best choice for more amounts of CO_(2).Real working capacity of Mg-MOF-74 is up to 0.38 mol•kg−1 at 70°C,which is twice as much as that of zeolite 13X.While zeolite 13X&R134a shows the best performance of two cycles in view of exergy efficiency and COP,which could reach 81.9%and 7.21,respectively,at 35°C.These matches will provide some guidelines for the practical application of the combination of DAC with heating,ventilation and air conditioning(HVAC).