TiO2/Nb2O5/carbon xerogel ternary photocatalyst for efficient degradation of 4-chlorophenol under solar light irradiation

TiO2-Acetylacetone as an Efficient Source of Superoxide Radicals under Reduced Power Visible Light: Photocatalytic Degradation of Chlorophenol and Tetracycline

“…The photodegradation of 4-CP and TC under visible light with the addition of • O 2 − scavenger confirms the efficient generation of • O 2 − radicals by TiO 2 -ACAC CTC (Figures 3 and 5), in accordance with the EPR characterization and DFT studies carried out on LMCT complexes [16,25,26]. On the other hand, the •OH radicals were not efficiently generated by TiO 2 -A300 CTC under visible light, resulting in the lower photodegradation of 4-CP than the photodegradation of TC, since •OH radicals are the dominant ROS in the 4-CP photodegradation [4,7,32], while • O 2 − radicals play a key role in TC degradation [5]. Figure 6 represents an update of the photocatalytic reactions conducted by TiO 2 -A300 CTC for the ROS generation and consequent degradation of 4-CP and TC.…”

“…The observed photodegradation of 4-CP was 32.8% ± 3.1% after 6 h and was within the error of the degradation measured for TiO 2 -A300 without the addition of the IPA scavenger. On the other hand, Moraes et al [4] revealed that with the addition of the IPA, the degradation of 4-CP (10 mg•L −1 ) using nanometric anatase (0.2 g•L −1 ) was about two times lower in comparison to the degradation without the addition of the IPA, however, under UV light and after 3 h. Therefore, these data indicate that hydroxyl radicals played an important role in the degradation of 4-CP for TiO 2 under UV light, since it promoted the formation of e − /h + pairs and, consequently, •OH radials. The results reported by Moraes et al [4] are in accordance with studies that show that •OH radicals have a dominant role in photodegradation of 4-CP [32,38].…”

“…The intensive use of drugs for the treatment of human health and industrial wastewater disposal are potential sources of contamination of aqueous effluents [1][2][3][4]. Currently, water treatment plants are not designed for the remediation of pharmaceutical and personal care products (PPCPs) [1,2].…”

“…An example of PPCPs is the antibiotic tetracycline, used to prevent bacterial infections, found in sewage from the pharmaceutical industry, hospitals, and livestock [5,6]. The remediation of organic compounds, such as chlorophenol, is a priority due to its high toxicity, low biodegradability, and carcinogenic and endocrine disruptive properties [4,7].…”

“…However, to the best of our knowledge, the individual potential of ROS in the LMCT systems has not been evaluated for photocatalytic applications. The ROS scavengers have been, however, already employed to other photocatalysts in photocatalytic measurements in the liquid medium to assess the individual potential of each ROS [4,6,[27][28][29][30].…”