Abstract:In this study, UV irradiation combined with chlorine (UV/chlorine) was used to degrade naproxen (NPX), a typical non-steroidal anti-inflammatory drug (NSAID) widely used for the treatment of symptoms associated with inflammation, in water. Compared with UV irradiation alone and direct chlorination, the UV/chlorine process shows a synergistic effect on NPX degradation. The effects of different factors, including the chlorine dose, solution pH, and the presence of Cl À , HCO 3 À or humic acid (HA), on NPX degrad… Show more
“…Seven main intermediates with m/z of 262, 216, 216, 200, 188, 170, and 358 were identified in the process of NPX photodegradation. The detection of intermediates was based on the transformation pathway of NPX degradation in the previous research literatures [4,6,[31][32][33][34]. The methyl and methoxyl groups on the aromatic ring are the two sites easily attacked by reactive oxygen species [6].…”
Section: Photodegradation Intermediates and Suggested Pathwaysmentioning
The development of photocatalysts with visible light response is of great significance to cope with energy crisis and environmental remediation. In this study, a visible light-driven photocatalyst reduced graphene oxide/ZnIn2S4 (rGO/ZIS) was prepared by a facile one-pot hydrothermal method. The photocatalyst was used for the degradation of naproxen under visible light illumination and it exhibited remarkably degradation efficiency (nearly 99% within 60 min). The improved photocatalytic degradation performance can be attributed to the enhancement of light adsorption capacity and effective separation of photoinduced electron–hole pairs. The reactive species quenching experiments and EPR measurements demonstrated that superoxide radical (O2−) and hole (h+) play a dominant role in the photocatalytic degradation reactions. In addition, the degradation intermediates were identified and the degradation pathway was suggested.
“…Seven main intermediates with m/z of 262, 216, 216, 200, 188, 170, and 358 were identified in the process of NPX photodegradation. The detection of intermediates was based on the transformation pathway of NPX degradation in the previous research literatures [4,6,[31][32][33][34]. The methyl and methoxyl groups on the aromatic ring are the two sites easily attacked by reactive oxygen species [6].…”
Section: Photodegradation Intermediates and Suggested Pathwaysmentioning
The development of photocatalysts with visible light response is of great significance to cope with energy crisis and environmental remediation. In this study, a visible light-driven photocatalyst reduced graphene oxide/ZnIn2S4 (rGO/ZIS) was prepared by a facile one-pot hydrothermal method. The photocatalyst was used for the degradation of naproxen under visible light illumination and it exhibited remarkably degradation efficiency (nearly 99% within 60 min). The improved photocatalytic degradation performance can be attributed to the enhancement of light adsorption capacity and effective separation of photoinduced electron–hole pairs. The reactive species quenching experiments and EPR measurements demonstrated that superoxide radical (O2−) and hole (h+) play a dominant role in the photocatalytic degradation reactions. In addition, the degradation intermediates were identified and the degradation pathway was suggested.
“…However, these technologies may have some drawbacks; for example, AOPs may induce high energy consumption of the UV lamp and the generation of more toxic products. 42,43 Adsorption cannot completely remove contaminants from the environment, and the catalytic process may introduce new chemicals into the water, which may cause new problems.…”
Section: Introductionmentioning
confidence: 99%
“…42,43 Adsorption cannot completely remove contaminants from the environment, and the catalytic process may introduce new chemicals into the water, which may cause new problems.…”
a Clofibric acid is one of the most frequently detected pharmaceuticals in various aquatic environments.Photodegradation of clofibric acid in water under simulated sunlight was investigated. The effects of different initial concentrations, pH conditions and dissolved oxygen were examined. Photodegradation of clofibric acid followed a pseudo-first-order kinetics model, and the rate decreased gradually with the increasing initial concentration of clofibric acid. Dissolved oxygen inhibited the photodegradation of clofibric acid. As a result of varying reaction species of clofibric acid, the initial pH conditions greatly influenced its photodegradation. Quenching experiments showed that the self-sensitization process via $OH and
“…In pathways II and III, NPX oxidation was performed by h + and ·O 2− and carbon-based radical species were formed by decarboxylation 117 . All produced intermediates during the process were decomposed by ring-opening reactions to malic acid, succinic acid, propionic acid and acetic acid, and finally mineralized to CO 2 and H 2 O 39 , 118 , 119 . Figure 15 Photo degradation reaction mechanism of NPX by ZrO 2 /TiO 2 /Fe 3 O 4 .…”
In this study, ZrO2, TiO2, and Fe3O4 components were synthesized by co-precipitation, sol–gel, and co-precipitation methods, respectively. In addition, solid-state dispersion method was used for synthesizing of ZrO2/TiO2/Fe3O4 ternary nanocomposite. The ZrO2/TiO2/Fe3O4 nanocomposite was characterized by different techniques including XRD, EDX, SEM, BET, FTIR, XPS, EELS, and Photoluminescence (PL). The FTIR analysis of ZrO2/TiO2/Fe3O4 photocatalyst showed strong peaks in the range of 450 to 700 cm−1, which represent stretching vibrations of Zr–O, Ti–O, and Fe–O. The results of FTIR and XRD, XPS analyses and PL spectra confirmed that the solid-state dispersion method produced ZrO2/TiO2/Fe3O4 nanocomposites. The EELS analysis confirmed the pure samples of Fe3O4, TiO2 and ZrO2. The EDAX analysis showed that the Zr:Ti:Fe atomic ratio was 0.42:2.08:1.00. The specific surface area, pores volume and average pores size of the photocatalyst were obtained 280 m2/g, 0.92 cm3/g, and 42 nm respectively. Furthermore, the performance of ZrO2/TiO2/Fe3O4 nanocomposite was evaluated for naproxen removal using the response surface method (RSM). The four parameters such as NPX concentration, time, pH and catalyst concentration was investigated. The point of zero charge of the photocatalyst was 6. The maximum and minimum degradation of naproxen using photocatalyst were 100% (under conditions: NPX concentration = 10 mg/L, time = 90 min, pH = 3 and catalyst concentration = 0.5 g/L) and 66.10% respectively. The stability experiment revealed that the ternary nanocatalyst demonstrates a relatively higher photocatalytic activity after 7 recycles.
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