Synthesis of Nano-sized SAPO-34 via Concentrated Gel Conversion Method and Its CH4/N2 Separation Performance

Nano-sized SAPO-34 molecular sieve with a thickness of ca. 50 nm was synthesized by concentrated gel conversion method. The obtained samples were characterized by means of XRD , SEM, ICP as well as N-2 adsorption-desorption isotherms (77 K). The results show that the synthesized nano-sized SAPO-34 has higher specific surface area (818.68 m(2)/g) and pore volume (0.57 cm(3)/g) compared with the micron cubic SAPO-34(2 mu m). With higher specific surface and pore volume, the adsorption capacity of CH4 on the nano-sized SAPO-34 is greatly increased(60%) , reaching 25.74 cm(3)/g, which is higher than most of the commercial zeolite adsorbents. At the same time, the adsorption selectivity of CHIN, is not significantly decreased (3.1) , and reaches the level of commercial adsorbents (>3.0). Through CH4/N-2 (volume ratio 1:1) mixture gas breakthrough test, it is proved that the synthesized nano SAPO-34 is indeed an effective CH4/N-2 separation adsorbent and has great potential in the industrial application of coalbed methane enrichment and denitrification.