Influence of the Photoreactor Configuration and of Different Light Sources in the Photocatalytic Treatment of Highly Polluted Wastewater

Abstract

In this study, a highly polluted wastewater from tannery industry is treated by photocatalysis using home-made N-doped TiO2 as catalyst. The doping by nitrogen of titania particles leads to a reduction in the absorption threshold from 3.2 to 2.5 eV, permitting the absorption of radiation characterized by a wavelength in the visible spectrum.Experiments were carried out by using different light sources, in particular white LEDs, blue LEDs, and UV lamps, with the aim to evaluate the process efficiency at different operating conditions. The obtained performances were compared with those using an undoped commercial TiO2 catalyst (Degussa P25).Moreover, a simplified mathematical model capable to correlate the power input of the used light sources, the geometrical properties of the reactor, and emitting sources spectra with the performances of the photocatalytic reaction was developed.

A Short Review of Techniques for Phenol Removal from Wastewater

“…In other work, Vaiano et al studied the degradation of organic matter present in tannery wastewater by means of an undoped commercial TiO 2 catalyst, Degussa P25, and Ndoped titania nanoparticles under UV or visible light irradiation, respectively. It was observed that P25 was only active in the presence of UV light whereas N-doped titania was potent in treating tannery wastewater in the presence of visible light emitted by LEDs [26].…”

Simultaneous Production of CH4and H2from Photocatalytic Reforming of Glucose Aqueous Solution on Sulfated Pd-TiO2Catalysts

“…In order to support a sustainable hydrogen economy, it is crucial to produce hydrogen cleanly and renewably. Typically, heterogeneous photocatalysis is studied with the aim of removing organic pollutants from wastewater [19,20] through oxidation reactions which can finally result in the production of CO 2 and water. An interesting approach is to explore, in parallel to wastewater treatment, opportunities of mass recovery which can be sold as secondary raw material or used as energy resources, such as hydrogen and methane.…”

N-Doped TiO2: An Efficient Catalyst for the Photocatalytic Treatment of Water and Wastewater under Visible Light Irradiation

“…The optimized formulation of N-TiO 2 has shown very effective in the removal of organic dyes, such as methylene blue and methyl orange [1], antibiotics such as spyramicin [2] and in the inactivation of E. coli [3]. It is also important to evidence that this optimized N-TiO 2 photocatalyst resulted also able to reduce the total chemical oxygen demand (COD) of a highly polluted wastewater such as tannery wastewater [4].A successful implementation of photocatalytic processes at large scales, however, calls for a global interdisciplinary view over the interplay between all the important parameters that affect the capture and utilization of photons in a photoreactor [4]. Moreover, one of the most important drawbacks of photocatalytic process is that photocatalysts are often used in slurry reactors.…”

“…The optimized formulation of N-TiO 2 has shown very effective in the removal of organic dyes, such as methylene blue and methyl orange [1], antibiotics such as spyramicin [2] and in the inactivation of E. coli [3]. It is also important to evidence that this optimized N-TiO 2 photocatalyst resulted also able to reduce the total chemical oxygen demand (COD) of a highly polluted wastewater such as tannery wastewater [4].…”

“…In this case, the experimental results were carried out by using different light sources, in particular white LEDs, blue LEDs and UV lamps, with the aim to evaluate the process efficiency at different operating conditions [4]. Utilizing the collected experimental data, it was developed a simplified mathematical…”