Heterogeneous catalytic ozonation: The significant contribution of PZC value and wettability of the catalysts

Investigation of the Removal of Several Micropollutants Presenting Different Ozone Reactivities from Natural Potable Water Matrix by the Application of Ozonation with the Use of SiO2 and Al2O3 as Catalysts

“…Both have been shown to enhance the production of hydroxyl radicals, and they present different PZC values and wettability. More details about their specific physicochemical characteristics can be found in Psaltou et al [17]. The examined solid materials were used without further purification; however, they were subjected to appropriate preparation by the application of preliminary ozonation before the experiments.…”

“…The examined solid materials were used without further purification; however, they were subjected to appropriate preparation by the application of preliminary ozonation before the experiments. Pre-ozonation is an important step in the relevant studies because it helps to simulate the real conditions of the respective full-scale applications (see Psaltou et al [17]). Acetonitrile, phosphoric acid, methanol, and water were used for the determination of micropollutants by the application of HPLC analytical technique; they were purchased from Chem-Lab (Zedelgem, Belgium) and Sigma-Aldrich (St. Louis, MO, USA).…”

“…Al 2 O 3 and SiO 2 are two commonly used inexpensive metal oxides that have been added as catalysts in similar research works [8,[14][15][16]. In one of our previously published studies, it was proven that Al 2 O 3 and SiO 2 materials can be characterized as effective catalysts for the removal of refractory organic compound p-CBA from deionized water by the application of the ozonation process [17]. These metal oxides present different surface charges at the common pH values of natural waters (i.e., pH close to 7.5).…”

“…The wettability of silica (SiO 2 ) is much higher than alumina (Al 2 O 3 ). The PZC values and the wettability are two properties that can greatly influence the contact of ozone with the surface of the catalyst, enhancing its subsequent decomposition towards hydroxyl radicals [17]. As a result, it is considered that the contact of ozone with the surface of alumina is favored due to the higher PZC value (being almost neutrally charged), whereas in the case of SiO 2 , the contact is favored by the higher wettability of the solid.…”

Removal of Paracetamol from Aqueous Solutions by Photocatalytic Ozonation over TiO2-MexOy Thin Films

“…This is the reason for a large number of studies regarding the development of catalytic systems capable of assisting the oxidative power of ozone mainly through the radical route. A large number of solids based on transitional metals in complex form or oxides, carbonaceous materials, etc., were studied for an evaluation of catalytic activity [22][23][24][25][26][27][28][29][30]. Additionally, catalyst precursors can be obtained from different industrial or agricultural wastes or pure metals salts.…”