Natural Zeolites as Sustainable Materials for Environmental Processes

In this chapter, the application of natural zeolites as sustainable materials for environmental protection is described. In particular, the clinoptilolite was studied for capturing carbon dioxide (CO2) emitted from industrial processes at moderate outlet temperatures and for wastewater remediation. Specifically, for CO2 capture and storage, the clinoptilolite was used as an adsorbent solid and it was tested at 20 and 65 °C. The wastewater treatment was achieved via Fenton-type reactions with a solution of azo-dyes acid orange 7 (AO7), as target molecule for azo dyes. The physico-chemical properties of the clinoptilolite, along with the ion-exchanged materials, were analyzed by means of N2 physisorption at −196 °C, X-Ray Diffraction (XRD), Field Emission Electron Microscopy (FESEM), and Energy Dispersive X-ray spectroscopy analysis (EDX). The results evidenced that the clinoptilolite can be a sustainable material for capturing CO2, because of the interesting adsorption capacity at moderate temperature. On the other hand, remarkable results for the AO7 degradation were obtained with the Fe-clinoptilolite catalyst in the presence of both ascorbic acid and H2O2.