Nitrate occlusion studies in Y zeolite and in a clay pillared with aluminium oxide

The occlusion of nitrates is a subject that is important, for instance, in soil amendment, as far as the control of the release of nitrates to the environment is concerned. In this work, the occlusion of molten nitrates was studied in the sodium form of zeolite Y and, to our knowledge, for the first time, in a pillared clay. The samples were characterized by different techniques, such as low-temperature nitrogen adsorption, X-ray diffraction, differential scanning calorimetry, FTIR, Na-23 MAS NMR and N-15 MAS NMR. From the different techniques evidence was obtained that supports the existence of occluded nitrates in the studied samples. Both materials, i.e., zeolite Y and the clay from Wyoming pillared with aluminum oxide, seem to have a potential in the release of nitrates for use in soil amendment. (C) 2002 Elsevier Science Inc. All rights reservzed.