Synthesis of zeolite materials from asbestos wastes: An economical approach

Several types of zeolite materials were synthesized using industrial asbestos wastes, which were of different natures and origins: Cords (S1) and Plates (S2) of thermal insulation, but also a specimen of the Jussieu building in Paris (S3). This revaluing process includes two steps. Firstly, the alteration of the wastes into amorphous silica is achieved by acid leaching with H2SO4 at different concentrations for variable periods of time. Preliminary characterizations performed on the treated materials revealed the presence of amorphous compounds that confirmed the structural damage of asbestos fibers. Secondly, zeolite materials such as Na-A (LTA), Na-X (FAU), silicalite-1 (pure silica MFI zeolite) and BEA are synthesized using the resulting amorphous compound as a unique silica source. The obtained materials were fully characterized by usual techniques. Amorphous silica derived from asbestos wastes is found to be an economical and highly reactive source for the zeolite synthesis.