Adsorption of Carbon Dioxide from Gas Streams via Mesoporous Spherical-Silica Particles

A relatively new mesoporous silica sorbent for environmental protection applications (i.e., mesoporous spherical-silica particles [MSPs]), was modified by N-[3(trimethoxysilyl)propyl]ethylenediamine (EDA) solution and was tested for its potential in the separation of carbon dioxide (CO2) from flue gas. The CO2 adsorption capacity of MSP and MSP(EDA) increased with temperature from 20 to 60 degrees C but decreased with temperature from 60 to 100 degrees C. The mechanism of CO2 adsorption on both samples is mainly attributed to physical interaction regardless of temperature change. The MSP(EDA) have good adsorption performance as compared with EDA-modified zeolite or granular activated carbon conducted in this study and many types of silica sorbents reported in the literature. The cyclic CO2 adsorption showed that spent MSP(EDA) could be effectively regenerated at 120 degrees C for 25 min and CO2 adsorption capacity of MSP(EDA) was preserved during 16 cycles of adsorption and thermal regeneration. These results suggests that MSP(EDA) are efficient CO2 sorbents and can be stably used in the prolonged cyclic operation.