Kinetics and mechanism of aqueous degradation of carbamazepine by heterogeneous photocatalysis using nanocrystalline TiO2, ZnO and multi-walled carbon nanotubes–anatase composites

Photochemical Fate of Carbamazepine in Surface Freshwaters: Laboratory Measures and Modeling

“…Note that I, II, IV, V, VI, VIII have also been detected with TiO 2 /UV, 28 Modeling of intermediates photogeneration. Intermediates I, II, IV, V are formed from CBZ via direct photolysis and reaction with • OH, with different yields depending on the process (see Table 1).…”

“…While some authors suggest that CDOM occurrence would inhibit CBZ direct photolysis by an inner-filter effect, 18,23,24 others underline the key role of CDOM as photosensitiser, although the reactive species involved in CDOM photosensitization were not reported. 17,[19][20][21] Additionally, and perhaps most importantly, despite the many studies aimed at identifying CBZ phototransformation intermediates under a wide variety of environmentally or technologically significant conditions, e.g., [27][28][29][30] there has been no attempt so far to predict or model the formation kinetics of intermediates in the environment, let alone under variable conditions of water chemical composition and depth. Finally, because of the large overlap between CBZ biotransformation and phototransformation metabolites/intermediates, the same compounds are produced by quite different processes.…”

“…Finally, because of the large overlap between CBZ biotransformation and phototransformation metabolites/intermediates, the same compounds are produced by quite different processes. 1,[27][28][29][30][31] Largely out of this reason, to date there is no indication of which intermediates could be used as reliable markers of CBZ phototransformation in the environment. Therefore, it is presently not possible to distinguish between human metabolism, the (however limited) WWTP processing and photochemistry, as sources of CBZ intermediates in surface waters.…”

Syntheses of Carbon Nanotube-Metal Oxides Composites; Adsorption and Photo-degradation

“…The first is adsorption ability of the nanotubes since the adsorption is a key process in the catalytic destruction of organic pollutants. While the second is the electron transfer from nanoparticels into the nanotubes, in other words the electron injection (Xu et al, 2010& Martinez et al, 2011. In general, irradiation of metal oxide semiconductor with a photon of sufficient energy, greater or equal to band gap energy could promote an electron from valence band (VB) to conduction band (CB).…”

Impact of water quality on removal of carbamazepine in natural waters by N-doped TiO2 photo-catalytic thin film surfaces

“…The main limitation of TiO 2 is a relatively wide band gap, (3.02 eV for rutile, 3.2 eV for anatase) [14], which results in about 5% spectral overlap between its absorbance and sunlight emission (λ < ~390 nm). Different attempts to overcome this drawback have made use of physical and chemical means such as morphological modifications to increase active surface area [15], use of other semiconductors such as WO 3 or ZnO, used with TiO 2 or as independent catalysts [16,17], and doping the TiO 2 with different elements, such as nitrogen. Asahi et al [18] were one of the first to describe N-doped TiO 2 materials.…”