Application of surfactant-template technique for preparation of sodium zirconate as high temperature CO2 sorbent

摘要

The purpose of this work was to study the characterization and CO2 sorption behavior of sodium zircon-ate (Na2ZrO3) nanoparticle prepared using surfactant template/ultrasound assisted method. The behavior of prepared Na2ZrO3 adsorbents was also compared with that of Na2ZrO3 prepared by (i) simple surfactant template method (without sonication) and (ii) conventional precursor liquid-state mixing. Samples prepared by surfactant template technique were found to be instable during the very high temperature operation, resulting in the loss of material porosity and creation of sintered particles. Therefore, less activity of Na2ZrO3 samples fabricated by surfactant template (with or without sonication) was obtained during cyclic CO2 sorption operation. For example, the conventional Na2ZrO3 sample (NaZr-5) fabricated by simple liquid-mixing method was characterized by about 10% CO2 uptake capacity reduction at the end of the fourth adsorption cycle conducted under pure CO2, while the sample NaZr-1 (the most efficient sample among all adsorbents prepared by the surfactant template/sonication technique) resulted in about 23% capacity reduction. The sorption behavior at different CO2 partial pressures confirmed an adequate performance of all prepared samples even at CO2 partial pressure as low as 0.3 bar. However, the further decrease to 0.1 bar resulted in considerable reduction in CO2 uptake capacity and kinetics. The adsorption results for sample NaZr-5 were modeled using the double exponential equation representing both CO2 chemisorption and ion diffusion processes.