TiO2/clinoptilolite composites for photocatalytic degradation of anionic and cationic contaminants

The present work aims to study the bulk and surface properties of the TiO2/clinoptilolite composite on the crystalline structure, superficial area, bandgap energy, zeta potential, particle size distribution, and chemical composition; in order to analyze the effect of the clinoptilolite proportion in the photocatalytic degradation of pollutants. TiO2/clinoptilolite composites were prepared by adding different mass proportions of clinoptilolite to a sol-gel bath containing TiCl4 as the titania precursor. Surface charge studies explain the larger sensitivity to composite ratio observed in the photocatalytic degradation of anionic pollutants than in cationic dyes. An optimum TiO2/clinoptilolite ratio of 90/10 was found to be the most efficient in terms of lower tendency to agglomeration, largest surface area, and increased crystallite size. Improvement in composite surface area occurs only at low clinoptilolite wt% and seems to be caused by lower agglomeration of nanometric TiO2 and acid-induced porosity in the zeolite.