Synthesis, characterization and high temperature CO2 capture capacity of nanoscale Ca-based layered double hydroxides via reverse microemulsion

In this study, we report a reverse microemulsion method to prepare stable homogeneous suspensions containing dispersed Ca-Al layered double hydroxide (LDH) nanoparticles. By changing the concentration, reaction time and temperature, the nano-particles with different structural morphology was developed from amorphous aggregation to platelet, regular hexagon and hydrangea-like hierarchical structure. The crystallization and growth of Ca-Al LDH nanoparticles were involved with a nucleation and growth process under nonaqueous polar solvent/surfactant system. After calcination at 700 degrees C, the calcined nano-sized Cal-Al LDH powders synthesized from the reverse microemulsion display remarkable CO2 capture behavior at 600 degrees C, which is strongly dependent on the reaction conditions (concentration, time and temperature). The calcined powder synthesized at 80 degrees C exhibits a faster rate of CO2 absorption and higher CO2 capture capacity of 44 wt% CO2 without apparent degradation under multiple cycles of carbonation-calcination. (C) 2013 Elsevier B. V. All rights reserved.