Abstract: The invention relates to a process for modifying a molecular sieve, whereby the molecular sieve is brought into contact with a modifying agent containing at least one weak acid, a salt of a weak acid or a derivative of a weak acid of at least one element of Groups III, IV or V of the Periodic Table of Elements, by dry mixing the molecular sieve and the modifying agent, optionally followed by adding liquid to form a slurry or paste, whereafter the resulting mixture is subjected to a thermal treatment.

Abstract: The invention relates to a process for the separation of at least one gas from a mixture containing at least two gases, which process comprises contacting a pore containing molecular sieve with the mixture of gaseous components, selectively adsorbing at least one component of the mixture in the pores of the molecular sieve, separating the molecular sieve from the non-adsorbed component or components and optionally desorbing the adsorbed component or components, the molecular sieve having been modified with a modifying agent containing at least one weak acid, a salt of a weak acid, or a derivative of a weak acid of at least one element of the Groups III, IV and V of the Periodic Table of Elements.