Effects Of Calcination Temperature On The Structure And CO_2 Sorption Properties Of Li_4SiO_4 Sorbents From Rice Husk Ash

摘要

Highly efficient Li_4SiO_4-based sorbents for CO_2 capture at high temperature, were developed using waste rice husk ash (RHA). Two different RHAS resulted from different calcination temperature as raw materials for preparing the Li_4SiO_4-based sorbents. These raw ashes and their resulting Li_4SiO_4-based sorbents were characterized by X-ray diffraction, thermogravimetry (dynamic and isothermically), and nitrogen adsorption. CO_2 sorption stability was investigated in a dual fixed-bed reactor. The characteristic results showed that high calcination temperature could lead to crystalline silica, which may produce the lower crystalline size, higher porosity and larger surface area as compared with the case of low temperature. This favourable structure appeared to be the main reason for increasing in CO_2 capture performance and kinetic behavior as illustrated by the thermogravimetric analyses. This pretreatment Li_4SiO_4-based sorbent also maintained a higher capacity during the multiple cycles. It was concluded that the synthesis of Li_4SiO_4-based sorbents obtained from biomass ash is a promising approach for CO_2 capture at high temperature.