The synthesis of mesoporous aluminosilicate using microcline for adsorption of mercury(II).

An economical mesoporous aluminosilicate was synthesized with microcline as starting material and the precursor 13X zeolite as seed for crystal structure on mesoporous walls. In this method, a mixture of microcline and Na2CO3 with a molar ratio of 1:1.05 was first calcined at 1093 K for 2.5 h. The calcined materials were mixed with 35 ml C16TMABr aqueous solution (containing 8.2 g C16TMABr) and the precursors of 13X zeolite, resulting in mesoporous aluminosilicate after crystallization of the solution at 378 K for 48 h and calcination of the powder at 823 K for 5 h. The as-synthesized sample has a uniform pore diameter distribution centered at 3.7 nm. The as-synthesized sample had BET surface area of 725 m2/g and BJH mean pore diameter of 3.7 nm. The FT-IR results revealed that the building units of 13X zeolite were inserted into the pore walls of the as-synthesized sample. The adsorption ratio of mercury(II) onto the as-synthesized adsorbent was about 95%. The adsorption process was found to be spontaneous and can be explained by particle diffusion and chemical ion-exchange mechanisms. The equilibrium concentration of mercury(II) using the as-synthesized sample as the adsorbent was under 1 microg/L, making the concentration of mercury meet the limit for drinking water in China as recommended by the World Health Organization.