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This paper outlines the synthesis and application of a sustainable composite for the photo-Fenton-like degradation of caffeine, bisphenol A, and simazine. The phase, morphology, optical and magnetic properties of the samples were evaluated by different characterization techniques. The composite of Fe 2.5 Co 0.3 Zn 0.2 O 4 and copper-chromium layered double hydroxide (CuCr-LDH) was determined to be the most favorable photocatalyst in the photo-Fenton-like process when compared with Fe 3 O 4 , Fe 2.5 Co 0.3 Zn 0.2 O 4 , CuCr-LDH, and Fe 3 O 4 /CuCr-LDH composite. Studying the efficiency of the photo-Fenton-like degradation process in the presence of the Fe 2.5 Co 0.3 Zn 0.2 O 4 /CuCr-LDH composite revealed a degradation rate constant of caffeine twice more than the sum of those obtained for the individual processes. This ascribes to the synergistic effect by which the photo-generated electron-hole from the catalyst and the efficient reduction of Fe3+, Cu2+, etc. during the photo-Fenton-like reaction is accelerated. Moreover, under the optimal condition and after 120 min of heterogenous photo-Fenton-like process at natural pH, > 90% of pollutants mixture was decomposed. The experiments fulfilled in near-real conditions demonstrated I) the high stability and magnetically recoverability of the photocatalyst and II) the proper degradation performance of the applied heterogenous photo-Fenton-process in the removal of pollutant mixture in different water bodies and in the presence of chloride and bicarbonate ions. [Display omitted] • Co 0.3 Zn 0.2 Fe 2.5 O 4 /CuCr-LDH composite as sustainable photocatalyst was synthesized. • Photo-Fenton-like process showed a synergetic effect in degradation of pollutants. • Under the optimal condition almost 90% of pollutants mixture was degraded. • 68% of TOC removal was observed for the pollutants mixture after 4 h of process. • Different water types and available inorganic ions showed a low inhibiting effect. [ABSTRACT FROM AUTHOR]

TiO 2 nanotube (TNT) layers are prepared via electrochemical anodization of Ti foil in ethylene glycol-based electrolyte containing fluoride ions. Using spin-coating of Fe(III) precursor solutions of different concentrations (10 µM to 10 mM), iron surface-modified TNT (Fe-TNT) layers are formed after annealing at 450 °C for 2 h in air. The Fe-TNT layers are comprehensively characterized by XRD, SEM, DRS and XPS. To identify and assess the contribution of photocatalysis and Fenton-based processes that are simultaneously triggered by Fe-TNT layers, degradation of caffeine is investigated in the dark and under UVA with and without the presence of 500 µM H 2 O 2. It has been found that in the presence of H 2 O 2 under UVA, 100 µM Fe-TNT can degrade 67 % of caffeine after 3 h, of which 4 % is from photolysis, 23.5 % from photocatalysis and 39.5 % from Fenton-based processes. It is important to note that Fenton-based reactions are due to the iron leaching, while the main reactive oxygen species are identified as hydroxyl radicals. In addition, the main degradation by-products are identified by LC-MS and IC-MS techniques, thus leading to the proposal of different degradation pathways of caffeine. To sum up, the research's findings provide novel insights into the concept of photochemical versatility, which is only obliquely explored in the corpus of previous research. [Display omitted] • Fe modified TiO 2 nanotube layers trigger simultaneous processes. • Contribution of photocatalysis, Fenton and photolysis is assessed for the first time. • Fenton process is dependent to iron leaching from Fe-TiO 2. • Efficient degradation of caffeine under UVA in the presence of H 2 O 2. • Degradation pathway of caffeine is proposed using LC-MS and IC-MS data. [ABSTRACT FROM AUTHOR]

The crucial role of manganese(III) species in the oxidative and catalytic reactivity of manganese oxides have been widely reported. However, the direct activation of radical precursors by Mn(III) oxides is still a matter of discussion. In this work, the ability of Mn(III)-bearing oxide (Mn 2 O 3) for activation of peroxydisulfate (PS) and peroxymonosulfate (PMS) was evaluated and compared using caffeine (CAF) as a model pollutant. Complete CAF removal was achieved with 5 mM of PS or PMS after 8 h of reaction time, whereas 48% of mineralization was obtained after 70 h of reaction when PMS was used as oxidant. Electron paramagnetic resonance spin trapping (EPR) and radical scavenging experiments showed that the sulfate radical (SO 4 •–) was the dominant radical in the Mn 2 O 3 /PMS system. In comparison, a non-radical mechanism such as Mn 2 O 3 surface-activated PS promoted the removal of CAF in the system of Mn 2 O 3 /PS. Liquid chromatography coupled to mass spectrometry analyses enabled the detection of main degradation products and the proposition of the CAF degradation pathways. Investigations in the real sewage treatment plant water showed that the decrease of CAF removal observed in wastewater as compared to pure water can be alleviated by increasing the Mn 2 O 3 dosage. These findings highlight the great ability of Mn-species in PS or PMS activation in different water matrices, which have important implications for the development of novel wastewater treatment technologies. [Display omitted] • Mn 2 O 3 with PS and PMS systems are able to degrade and mineralize caffeine in water. • The CAF degradation mechanism via radical and non-radical pathways is elucidated. • Mn 2 O 3 /PMS system is found to be more efficient for caffeine degradation in STPW. • Mn(III)-based AOPs can be considered as promising and efficient water treatments. [ABSTRACT FROM AUTHOR]