Photodegradation Efficiencies in a Photo-CREC Water-II Reactor Using Several TiO₂ Based Catalysts

Abstract

This study reports phenol degradation using several TiO2 photocatalysts (DP25, Anatase 1, Hombikat UV-100, Anatase 2) in a Photo-CREC Water-II Reactor. The physicochemical properties of the photocatalysts used, such as crystallinity, superficial area, and pore size distribution are reported. Reactor efficiencies are calculated using both Quantum Yields (QYs) and Photochemical and Thermodynamic Efficiency Factors (PTEFs). This is accomplished using phenol and phenol intermediate photoconversion rates. This allows the determination of hydroxyl radical consumption rates, at every step of the photodegradation process. With these data, and with the absorbed photon rates, energy efficiencies are calculated. It is shown that for the best performing photo catalysts the maximum QYs reach 50 % levels. These favourable photoconversion efficiencies confirm the critical importance of having available highly performing photocatalysts and photoreactors, such is the case of Photo-CREC Water-II Reactor unit.

Photochemical Thermodynamic Efficiency Factors (PTEFs) for Hydrogen Production Using Different TiO2 Photocatalysts

“…The quantum yield definition established for the photoconversion of chemical species − ,,, has to be modified for hydrogen production. As reported in eq , the φ H 2 shall involve H • radicals, which are the primary chemical species leading to the formation of H 2 as follows Thus, the φ H 2 accounts for hydrogen production as a ratio of the H • radical species produced over the number of photons absorbed in the Pt- or Pd-doped TiO 2 . ,, ,, This is only the case if all photons absorbed lead to hydrogen formation.…”

“…They are used to calculate the energy efficiencies during the photocatalytic photoconversion or during the photocatalytic photodegradation of organic pollutants. The significance of energy efficiencies has been stressed in recent years in the scientific technical literature by our research team. ,,− Proposed efficiency factors are as follows The analysis of photocatalytic processes for organic pollutant conversion showed that the maximum value to be assigned to η OH • was 1.33 …”

“…Quantum Yield for Photocatalytic Hydrogen Production (φ H 2 ). The quantum yield definition established for the photoconversion of chemical species [9][10][11]13,14,18 has to be modified for hydrogen production. As reported in eq 4, the φ H 2 shall involve H • radicals, which are the primary chemical species leading to the formation of H 2 as follows…”

Photo-degradation of P-Nitro Toluene Using Modified Bentonite Based Nano-TiO2 Photocatalyst in Aqueous Solution

“…Aby et al [18] published an article on how to make a nano-silver and zinc (Ag/ZnO) photocatalyst and demonstrated its elevated efficiency. The effect of photocatalyst degradation on organic pollutants such as some dyes was investigated, and it was concluded that the efficacy of ZnO <Ag / ZnO (% 1wt) <Ag / ZnO (4 wt%) [18].…”

Photocatalytic Activity of TiO2 Thin Films: Kinetic and Efficiency Study

“…Heterogeneous photocatalysis is one of the advanced oxidation processes, which exhibit a significant potential for use in environmental remediation, hydrogen production and cancer treatment (de Lasa and Serrano Rosales 2009;Serrano Rosales et al 2016;Fujishima and Zhang 2006). Photocatalytic reactions are result of interaction between photons with the appropriate wavelength and a solid semiconductor (Linsebigler, Lu, and Yates 1995;Fujishima, Zhang, and Tryk 2008).…”