Photomineralization of phenol on Al2O3: synergistic photocatalysis by semiconductors

Abstract

Phenol gets adsorbed on Al 2 O 3 and mineralizes under UV light in the presence of dissolved O 2 . The degradation exhibits first-order kinetics and its rate increases linearly with the light intensity and decreases with pH. 2,4-Diphenoxycyclohexanone and 2,6-diphenoxycyclohex-3-ene-1-ol are the intermediates of the reaction. While particulate TiO 2 , ZnO, ZnS, Fe 2 O 3 , CuO, CdO, and Nb 2 O 5 individually photocatalyze the degradation, each semiconductor exhibits synergistic photocatalysis, an enhanced photodegradation, when present along with Al 2 O 3 , indicating electron abstraction by illuminated semiconductors from the phenol adsorbed on Al 2 O 3 .

Photoinduced oxidative transformation of diphenylamine on Al2O3 with enhancement by ZnO synergism

“…The mean particle sizes (t) of Al 2 O 3 and ZnO, obtained using the formula t ¼ 6/rS, where r is the material density and S is the specific surface area, are 167 and 87 nm, respectively. The obtained powder X-ray diffractograms (XRD) show the alumina used as a blend of gamma and chi phases (g:c:52:48) and ZnO in hexagonal zincite lattice [16]. The mean crystallite sizes obtained from the XRD results agree with those deduced from BET surface area measurements.…”

“…The heterogeneous photoinduced reaction taking place in a continuously stirred tank reactor (CSTR) conforms to the kinetic law [16]:…”

Heterogeneous Fenton-like catalytic degradation of phenazine dye over CeO2 (CP-2) nanoscale powder

“…Thus, wastewater treatment, refinement, and recycling are crucial for environmental pollution control and industrial applications [2,3]. Recently, innovative approaches, such as advanced oxidation processes (AOPs) based on the in situ generation of highly reactive hydroxyl radicals ( • OH) have been recommended as the most effective technique for water and wastewater treatment owing to the enhanced biodegradability, extensive ability of recalcitrance substances degradation and mineralization as well as efficient toxicity reduction [4][5][6][7][8][9]. It is recognized that the conventional AOPs (O 3 , O 3 /UV, O 3 /H 2 O 2 , O 3 /H 2 O 2 /UV, O 3 /catalysts, UV/H 2 O 2 , Fe 2+ /H 2 O 2 , Fe 3+ /H 2 O 2 , and Fe 2+ /H 2 O 2 /UV) or with nonconventional AOPs (photo-electro-Fenton and sono-electro-Fenton processes) techniques are detrimental for effective treatment of wastewater [10][11][12][13].…”

In situ and ex situ synthesis of poly(vinyl alcohol)–Fe3O4 nanocomposite flame retardants

“…The principal benefits of these compounds over many metallic alloys are corrosion resistance, low density, and thermal insulation. However, the main disadvantage of polymeric compounds is high flammability (Karunakaran, Dhanalakshmi, & Gomathisankar, 2010;Grigsby, Ferguson, Franich, & Russell, 2005;Wang, Fang, Chen, & Wang, 2007;Henrist, Mathieu, Vogels, Rulmont, & Cloots, 2003;Laoutid, Bonnaud, Alexandre, Lopez-Cuesta, & Dubois, 2009).…”