Preparation method of iron ion exchange modified molecular sieve

Abstract

The invention provides a preparation method of an iron ion exchange modified molecular sieve. The preparation method comprises the following steps of (1) adding reduced iron powder and a matrix molecular sieve in an iron salt solution for carrying out ion exchange reaction; (2) carrying out solid-liquid separation on the iron salt solution after finishing the reaction; (3) washing an obtained solid product for removing the residual iron salt; (4) drying the product after washing; and (5) placing the product in a magnetic field for carrying out magnetic separation, so as to remove the iron powder. The preparation method provided by the invention has the advantages that the iron ion exchange modified molecular sieve with high exchange degree is obtained through once exchange, oxidation of ferrous ions is prevented without protection of inert environment, the generated residual matters which are not exchanged on the molecular sieve in a process are removed, and the pure exchange product is obtained.

Description

technical field [0001] The invention relates to a preparation method of a molecular sieve, in particular to a preparation method of an iron ion exchange modified molecular sieve. Background technique [0002] Iron ion exchange modified molecular sieve is a kind of valuable catalytic material, its x It shows excellent activity and selectivity in a series of catalytic reactions such as selective catalytic reduction (SCR). The usual method for preparing iron ion exchange modified molecular sieves is to obtain them through liquid-phase ion exchange or solid-phase ion exchange between molecular sieve precursors and iron-containing compounds. [0003] The traditional ion exchange is the aqueous solution ion exchange method developed in 1970S: the molecular sieve precursor is suspended in the exchanged metal cation aqueous solution for liquid-solid exchange. The general process can be described as: the suspension is stirred at a certain temperature, Then solid-liquid separation, ...

AI Technical Summary

Problems solved by technology

[0008] Aiming at the shortcomings of the traditional liquid-phase ion exchange and solid-phase ion exchange methods for preparing iron ion-exchange modified molecular sieves, the present invention aims to provide an improved preparation method for iron ion-exchange modified molecular sieves, which can overcome the exchange degree of ordinary liquid-phase ion exchange methods. Low, it needs to be repeated many times, and the ferrous ion is easily oxidized in the liquid phase. The iron ion exchange modified molecular sieve with high exchange degree can be obtained by one exchange; this method can prevent the ferrous ion from inert environment protection Oxidation, the remaining species that are not exchanged to the molecular sieve can be removed during the process, so as to obtain a relatively pure exchange product

Images