Abstract
A new composite photocatalyst called POF/TiO2 was prepared from commercial P25 TiO2 and Posidonia oceanica fibers (POF), a biomaterial collected from Tunisia’s beach. The composite material was prepared by a classical sol-gel synthesis and was characterized by different methods. SEM images show a TiO2 layer formed on top of the fibers, which was verified by XRD and XPS. Diffuse reflectance UV-vis spectroscopy shows that the layer has the same optical properties (Eg = 3.0 eV) as bulk P25. The photodegradation of phenol as a model compound was studied under different operating conditions using POF/TiO2 and the results show degradation efficiencies between 4% (100 ppm) and 100% (<25 ppm) after 4 h of UV-C light irradiation (254 nm) using a POF/TiO2 concentration of about 1 g/L. The composite material showed good stability and could be recycled up to three times.
Highlights
During the last years, clean water resources have become one of the most significant worries of governments due to population growth, a considerable increase in water withdrawal, and the production of large amounts of wastewater by various industries
The lower degradation efficiency with increasing phenol concentration is a combination of different effects taking place simultaneously: (a) more phenol adsorbs onto the surface of POFNaOH /TiO2, (b) fewer photons are adsorbed by the photocatalyst and photons might be adsorbed by phenol, and c) the formation of hydroxyl radicals decreases since the number of adsorption sites for the hydroxyl ions decreases
The POF/TiO2 photocatalyst was successfully prepared via a sol-gel route from Posidonia oceanica fibers as the support material and P25 as the TiO2 photocatalyst
Summary
Clean water resources have become one of the most significant worries of governments due to population growth, a considerable increase in water withdrawal, and the production of large amounts of wastewater by various industries. To avoid the agglomeration of photocatalyst particles and to improve their photocatalytic activity, they can be mixed with low cost and abundant materials forming composite photocatalysts as shown in the literature, e.g., clay for ZnO [14,15], zeolites for TiO2 [16,17], chitosan for TiO2 [18,19], perlite for TiO2 [20], and cellulose/lignocellulose for TiO2 [21,22] In many of these composite photocatalysts, the natural and abundant material acts as support for the photocatalyst particles, allowing a good dispersion of the titanium oxide particles while avoiding their agglomeration. Several operating parameters (e.g., phenol concentration, photocatalyst concentration, and light source) are varied to study their effect on the degradation efficiency
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