MODIFIED MOLECULAR SIEVE, PREPARATION METHOD THEREFOR, AND USE THEREOF

The present invention relates to the technical field of molecular sieves, and in particular to a preparation method for a modified molecular sieve, a modified molecular sieve prepared by the preparation method, and use of the modified molecular sieve. The preparation method comprises: (1) subjecting a Na-type molecular sieve to metal ion exchange to obtain a metal ion slurry; (2) adding a first precipitant to allow part of metal ions in the metal ion exchange slurry to be subjected to first precipitation to obtain a first precipitation slurry; (3) subjecting the first precipitation slurry to filtering, first ammonium sulfate exchange, first water washing, and first roasting sequentially to obtain a one-exchange one-roasting molecular sieve dry powder; and (4) adding a second precipitant to allow part of metal ions in the one-exchange one-roasting molecular sieve dry powder to be subjected to second precipitation, and then carrying out second ammonium sulfate exchange, second water washing, and optional second