Development of HMMM based Adsorbents by Nanocasting for CO2 Capture

Abstract

With CO2 being one of the main contributors to global warming, there is increasing interest in recovery of carbon dioxide (CO2) from flue gases. Post-combustion CO2 capture from the flue gases is one of the key technology options to reduce greenhouse gases, because this can be retrofitted to the existing coal-fired power stations. In view of this, in the past few years, several research groups have been involved in the development of new solid sorbents for CO2 capture from flue gas with superior performance and desired economics. The enhancement of specific adsorption capacity may be carried out by increasing the affinity of the adsorbent surface to CO2. Nitrogen enrichment is reported to be effective in introducing basic functionalities that enhance specific adsorbate-adsorbent interactions. A variety of promising sorbents such as activated carbonaceous materials, microporous/mesoporous silica or zeolites, carbonates, and polymeric resins loaded with or without nitrogen functionality for the removal of CO2 from the flue gas streams have been reviewed. In this work, we report successful synthesis of nitrogen-doped mesoporous carbon by templating or nanocasting method using HMMM as precursor and MCM-41 silica as sacrificial template. The templated carbon with nitrogen containing organic molecules was subjected to carbonization and activation over range of temperatures from 500-800 °C followed by removal of silica template. The resultant adsorbents were characterized for their chemical composition and textural properties. The effect of carbonization and adsorption temperature on CO2 uptake was studied. Adsorption capacities upto 0.801 mmol g-1 of CO2 at 30 ºC were measured using thermogravimetric analysis and discussed how textural and chemical properties of carbon influence CO2 capture performance. Finally, the stability and regenerability of the carbons over numerous thermal swing adsorption cycles have been described. Kinetics of adsorption was studied by using pseudo first order and pseudo second order kinetic models.