Iron-Modified Titanate Nanorods for Oxidation of Aqueous Ammonia Using Combined Treatment with Ozone and Solar Light Irradiation

Abstract

Sodium titanate nanorods were synthesized by a hydrothermal method and subsequently modified with an iron precursor. For comparison, Fe2O3 nanocubes were also obtained through a similar hydrothermal treatment. Pristine, Fe-modified nanorods and Fe2O3 nanocubes were suspended in diluted ammonia solutions (20 ppm) and exposed to ozone and simulated light irradiation. Ammonia abatement, together with the resulting nitrogen-containing products (NO3−), was monitored by ion chromatography measurements. The generation of reactive oxygen species (·OH and O2−) in the investigated materials and their photoelectrochemical behaviour were also investigated. Morphological and structural characterizations (SEM, XRD, XRF, UV–Vis, H2-TPR, NH3-TPD, PL, PZC) of the studied catalysts were correlated with their activity for ammonia degradation with ozone- and photo-assisted oxidation. An increase in ammonia conversion and a decreasing amount of NO3− were achieved by combining the above-mentioned processes.

Effect of the Modification of Catalysts on the Catalytic Performance

“…The authors further investigated the influence of the support properties, the presence of TiO 2 and Au species, and their interaction with amoxicillin photodegradation under UV and visible light irradiation. In another paper [7] pristine titanate nanorods were modified with iron to improve the light absorption and separation of photogenerated charges and to favor ammonia photodegradation under solar light irradiation. The morphological and structural characterizations (SEM, XRD, XRF, UV-Vis, H 2 -TPR, NH 3 -TPD, PL, PZC) of the studied catalysts were correlated with their activity on ammonia degradation with ozone-and photo-assisted oxidation.…”

“…The morphological and structural characterizations (SEM, XRD, XRF, UV-Vis, H 2 -TPR, NH 3 -TPD, PL, PZC) of the studied catalysts were correlated with their activity on ammonia degradation with ozone-and photo-assisted oxidation. Preda et al [7] optimized the aqueous ammonia oxidation process to obtain a high ammonia conversion and increase selectivity to gaseous nitrogen-containing products. In reference [8], the authors focused on the preparation of a ZnO/CuO/g-C 3 N 4 (ZCG) nanocomposite through an efficient co-crystallization method, performed a photocatalytic test for the treatment of dye-containing wastewater followed by visible light irradiation and evaluated the material's durability and recycling capability.…”