| abstract |
FIELD: chemistry. n SUBSTANCE: method for the zeolite material post-treatment that has a framework structure of the type LEV, SNA, MFI, MWW, BEA. In step (i), a zeolitic material is provided, in which the wireframe structure includes YO 2 and X 2 O 3 , where Y is Si, X is a trivalent element selected from the group consisting of Al, B, In, Ga, Fe, and combinations of two or more thereof. In step (ii), the zeolitic material treatment provided in step (i) is carried out by the method comprising: (a) treating the material with an aqueous solution having a pH value of not more than 5, wherein the aqueous solution comprises an organic acid and/or an inorganic acid; (b) treating the material produced in step (a) with a liquid aqueous system having a pH in the range of 5.5 to 8 at the temperature of, at least, 75°C, wherein the liquid aqueous system contains not less than 90 wt % of water. The pH value of the aqueous solution is determined by using a glass electrode sensitive to pH. n EFFECT: invention allows the degree of crystallinity of the treated zeolite to be maintained or increased. n 25 cl, 4 ex |