Synthesis and Characterization of SAPO-34 Nanoparticles For CO2 Capture

Synthesis of SAPO-34 nanocrystals which has been recently considered as a challenging task was successfully performed by sonochemical method using TEAOH as structure directing agent (SDA). The products were characterized by scanning electron microscope (SEM), transmittance electron microscope (TEM), X-ray diffraction (XRD), and Fourier transform Infrared (FTIR). From TEM results, the average crystal size of the final product prepared sonochemically is 25 nm that is much smaller than that of synthesized under hydrothermal condition and the morphology of the crystals changes from uniform spherical nanoparticles to spherical aggregates of cube type SAPO-34 crystals respectively. In a sonochemical process, a huge density of energy for crystallization is provided by the collapse of bubbles which formed by ultrasonic waves. The fact that small SAPO-34 crystals could be prepared by the sonochemical method suggests a high nucleation density in the early stages of synthesis and slow crystal growth after nucleation. After the characterization, SAPO-34 particles were tested for its CO2 adsorption characteristic. The effect of particle size on its adsorption behaviour was studied using CO2 physisorption analyzer. The CO2 adsorption isotherm results show that the size and crytallinity of SAPO-34 are important factors on the adsorptions of CO2. The smaller the size of SAPO-34 particles, the higher the adsorptions of CO2 rate. Thus, the reduction in particle size increase the surface area of the resulting SAPO-34, therefore, higher CO2 adsorption rate was obtained.