Preparation of zeolite coatings by induction heating of the substrate

Induction heating was used as a tool to prepare zeolite coatings on stainless steel substrates. The substrates were double-layer wire meshes which were placed in a Teflon reactor and were heated from a distance by the alternating magnetic field produced by a generator. The reaction mixture, also heated to some extent in the reactor, was circulated in the system to be cooled in a water bath to a temperature lower than that of the mixture at the exit of the reactor. Different synthesis conditions were investigated and the coatings obtained initially using two previously published synthesis compositions were characterized by X-ray diffraction (XRD) and thermogravimetry (TG). Induction heating was shown to allow the formation of crystalline zeolite A and X coatings. Relatively thick coatings of these zeolites could be prepared in much shorter times than by conventional synthesis, and even the substrate heating method using conduction. The cylindrical geometries of the induction coil and the substrate allowed the uniform heating of the substrate, leading to the formation of uniformly thick coatings. Utilizing substrates consisting of two layers of wire meshes, also played significant role in obtaining thick and highly stable coatings by the induction heating synthesis method.