Modification of molecular sievesl — direct fluorination

Structure and surface modification of a zeolite molecular sieve can be achieved by a dilute fluorine gas (0–20%) treatment under ambient temperature and pressure. Both dealumination and structural stabilization occur after the fluorine treatment. Depending on the treatment conditions, e.g. fluorine concentration and treatment duration, the surface characteristics (hydrophilicity and hydrophobicity) and the catalytic acidity can be modified.