Photocatalytic Oxidative Degradation of Carbamazepine by TiO2 Irradiated by UV Light Emitting Diode

Abstract

Here, ultraviolet light-emitting diodes (UV-LED) combined with TiO2 was used to investigate the feasibility of carbamazepine (CBZ) degradation. The effects of various factors, like crystal form of the catalyst (anatase, rutile, and mixed phase), mass concentration of TiO2, wavelength and irradiation intensity of the UV-LED light source, pH of the reaction system, and coexisting anions and cations, on the photocatalytic degradation of CBZ were studied. The mixed-phase (2.8 g/L) showed the best degradation efficiency at 365 nm among three kinds of TiO2, wherein CBZ (21.1 µM) was completely oxidized within 1 h. The results of batch experiments showed that: (i) CBZ degradation efficiency under UV-LED light at 365 nm was higher than 275 nm, due to stronger penetrability of 365 nm light in solution. (ii) The degradation efficiency increased with increase in irradiation intensity and pH, whereas it decreased with increase in initial CBZ concentration. (iii) The optimal amount of mixed-phase TiO2 catalyst was 2.8 g/L and excessive catalyst decreased the rate. (iv) The co-existence of CO32−, HCO3−, and Fe3+ ions in water significantly accelerated the degradation rate of photocatalytic CBZ, whereas Cu2+ ions strongly inhibited the degradation process of CBZ. ·OH was found to be the main active species in the UV-LED photocatalytic degradation of CBZ. UV-LED is more environmentally friendly, energy efficient, and safer, whereas commercial TiO2 is economical and readily available. Therefore, this study provides a practically viable reference method for the degradation of pharmaceuticals and personal care products (PPCPs).

Removal of Pharmaceuticals and Personal Care Products (PPCPs) by Free Radicals in Advanced Oxidation Processes

“…When the semiconductor makes contact with water, strongly oxidizing free radicals (i.e., HO•) are generated on its surface (as shown in Equations ( 1) and (2) [71,72]), which react with PPCPs and degrade them in water. As among the most promising photocatalyst materials, nano-TiO 2 is highly utilized to remove PPCPs from water, and nano-TiO 2 has been studied by numerous studies [73][74][75].…”

Performance of TiO2/UV-LED-Based Processes for Degradation of Pharmaceuticals: Effect of Matrix Composition and Process Variables

“…The fastest degradation was for SMX during UV-C photolysis, attaining better k app results without the catalyst. A possible explanation is that TiO 2 nanofilm may cause a screening effect, given that UV-C light has lower penetration capacities than UV-A [60]. Since UV-C photolytic degradation for SMX was already very fast (complete degradation in less than 45 min in the individual test), the presence of the TiO 2 nanofilm hinders the direct contact between SMX and photons, and the increase in degradation provided by ROS production does not compensate for the losses in available photons for the direct photolysis faster degradation route [61,62].…”

MOF-Derived Porous Fe2O3 Nanoparticles Coupled with CdS Quantum Dots for Degradation of Bisphenol A under Visible Light Irradiation

“…Driven by the increased awareness of the risks involved with EDCs, researchers have investigated many treatment processes that remove these chemicals from water. Photocatalytic oxidation technology has attracted much attention because it completely degrades organic pollutants in water [ 3 , 4 ]. As a typical n-type semiconductor, α-Fe 2 O 3 is an ideal candidate for photocatalytic treatment of wastewater, offering excellent chemical stability, a suitable band gap (2.3 eV) and nontoxicity.…”