Substituent effect on nano TiO₂‐ and ZnO‐catalyzed phenol photodegradation rates

Abstract

Photodegradation of phenol on TiO 2 P25 Degussa, TiO 2 Hombikat, TiO 2 anatase, and ZnO nanoparticles exhibits identical photokinetic behavior. The degradation rates of 15 ortho-, meta-and para-substituted phenols on the four semiconductor nanocrystals do not conform to the electronic effect of the substituents but show some common features. While the orthosubstituents slow down the reaction, nitro and hydroxyl groups enhance the same. The effects are rationalized. C 2008 Wiley Periodicals, Inc. Int J Chem Kinet 41: 275-

A Study of the Photocatalytic Oxidation of Humic Acid on Anatase and Mixed-phase Anatase–Rutile TiO2 Nanoparticles

“…2b. 3.2 pH Effect Figure 3a and b show the changes of VIS 400 -UV 254 and DOC-SUVA values of HA solution as a function of pH 3, 5, 6, and 9, respectively. pH zero-point-ofcharges (pH pzc ) of Fluka anatase TiO 2 is 5.8 (Karunakaran and Dhanalakshmi 2009). Below pH pzc the surface of anatase TiO 2 positively charged, while above the pH pzc surface is negatively charged.…”

Photocatalytic degradation of phenol by iodine doped tin oxide nanoparticles under UV and sunlight irradiation

“…Several studies have been carried out on the application of TiO 2 and ZnO for mineralization of organics [14][15][16][17][18]. A new class of activated iodine doped TiO 2 was found to enhance photocatalytic oxidation of phenol under UV and visible light illumination [19].…”

Comparative Assessment of the Photocatalytic Efficiency of TiO2 Wackherr in the Removal of Clopyralid from Various Types of Water

“…Because the real effluent stuff of pesticide can be discharged at a different pH, the pH effect on the photocatalytic rate degradation of CLP was studied in the pH range from 2.4 to 9.8 ( Figure 6). The point of zero charge (pH pzc ) of anatase is 5.8 (Karunakaran & Dhanalakshmi, 2009). Thus, the TiO 2 surface will be positively charged ( 2 TiOH  ) in acidic media (pH  pH pzc ) and negatively charged (TiO  ) in alkaline media (pH  pH pzc ).…”