Photocatalytic Degradation Of Carbamazepine Research Articles

Degradation of carbamazepine in surface water: performance of Pd-modified TiO2 and Ce-modified ZnO as photocatalysts.

Carbamazepine is a widely used antiepileptic drug to control and treat a variety of disorders that is frequently detected in surface water, and in municipal and urban wastewater. This recalcitrant pollutant could be removed by alternative advanced oxidation technology such as heterogeneous photocatalysis. Ce-modified ZnO and Pd-modified TiO2 were synthesized by a microwave-assisted sol-gel method. According to the characterizations (Raman spectroscopy, UV-Vis diffuse reflectance spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy), a mixture of oxides was determined in both materials: CeO2/ZnO and PdO/TiO2. Photocatalytic degradation of carbamazepine in pure water under visible light (3h) was assayed. The degradation percentage obtained with each catalyst was 80%, 53%, 20%, and 9% for ZnO, Ce-modified ZnO, TiO2, and Pd-modified TiO2, respectively. The leaching of Zn as a possible source of water contamination was tested, finding the lowest value for Ce-modified ZnO by adjusting the initial pH up to neutrality. Later, an environmentally relevant concentration of carbamazepine (228µg L-1) was assayed, using local surface water (pH = 8.3). Despite the presence of other compounds in the real water matrix, after 5h of photocatalysis, a 56% of degradation of the pharmaceutical and low leaching of Zn were achieved. The use of Ce-modified ZnO activated by visible light is a promising strategy for the abatement of pharmaceutical active compounds.

Photocatalytic degradation and pollutant-oriented structure-activity analysis of carbamazepine, ibuprofen and acetaminophen over faceted TiO2

Photocatalytic degradation of carbamazepine, ibuprofen, acetaminophen and phenol was studied in the presence of anatase photocatalyst, exposing three different crystal facets in the majority of {0 0 1}, {1 0 0} or {1 0 1}. It was found that octahedral anatase particles exposing {1 0 1} facets allow to achieve the best degradation and mineralization of all persistent organic pollutants. This confirms that the previous findings, showing high {1 0 1} activity, are not limited to phenol and could be generalized for other water pollutants. Based on the obtained results, a correlation model including exposed TiO2 crystal facet and chemical hardness of the pollutant was developed to predict the degradation rate of pollutants with a possibly diverse electronic structure. The structure-activity analyses, based on the reactivity predictors obtained from the DFT calculations for all tested compounds, have shown that pollutants with higher chemical hardness react faster with the photocatalyst. Alternatively, a similar effect was observed for the higher HOMO-LUMO energy gap of the compound. This relation indicates that for compounds with a low energy position of LUMO orbital, e.g., carbamazepine, process efficiency is not strictly dependent on the stability of h+ generated organic radical, which is often pointed out as an initial reactive form. Based on these results, a correlation model was developed for the first time to quantitatively describe the effect of the facet-pollutant interactions based on their independent electronic properties. Finally, this was followed by the detailed degradation study of the pharmaceuticals mixture, showing the impact of the total concentration and role of active species on the degradation efficiency over facet-engineered TiO2 photocatalysts.

Photocatalytic Activity of Sulfanyl Porphyrazine/Titanium Dioxide Nanocomposites in Degradation of Organic Pollutants.

Magnesium(II) sulfanyl porphyrazine with peripheral morpholinethoxy substituents was embedded on the surface of titanium(IV) dioxide nanoparticles. The obtained nanocomposites were characterized with the use of particle size and distribution (NTA analysis), electron microscopy (SEM), thermal analysis (TGA), FTIR–ATR spectroscopy, and X-ray powder diffraction (XRD). The measured particle size of the obtained material was 327.4 ± 15.5 nm. Analysis with XRD showed no visible changes in the crystallinity of the material after deposition of porphyrazine on the TiO2 surface. However, SEM images revealed noticeable changes in the morphology of the obtained hybrid material: higher aggregation and less ordered structure of the aggregates. The TGA analysis revealed the lost 3.6% (0.4 mg) of the mass of obtained material in the range 250–550 °C. In the FTIR–ATR analysis, C-H stretching vibratins in the range of 3000–2800 cm−1, originating from porphyrazine moieties, were detected. The photocatalytic applicability of the nanomaterial was assessed in photodegradation studies of methylene blue and bisphenol A as reference environmental pollutants. In addition, the photocatalytic degradation of carbamazepine with porphyrazine/TiO2 hybrids as photocatalysts was studied, accompanied by an HPLC chromatography assessment of photodegradation. In total, 43% of the initial concentration was achieved in the case of bisphenol A, after 4 h of irradiation, whereas 57% was achieved in the case of carbamazepine. In each photodegradation reaction, the activity of the obtained photocatalytic nanomaterial was proved with almost linear degradation. The photodegradation reaction rate constants were calculated, and revealed 5.75 × 10−5 s−1 for bisphenol A and 5.66 × 10−5 s−1 for carbamazepine.

Synergistic improving photo-Fenton and photo-catalytic degradation of carbamazepine over FeS2/Fe2O3/organic acid with H2O2in-situ generation

Herein, a heterogeneous photo-Fenton and photo-catalytic system was constructed using oxide pyrite (FeS2/Fe2O3) mineral and organic acids including tartaric acid (TA), ascorbic acid (AA), and citric acid (CA). In the proposed system, FeS2/Fe2O3 can be successfully activated through irradiation to generate photogenerated carriers, which generated H2O2in-situ through the reduction reactions between e- and O2. The addition of organic acids enhanced the dissolution of iron from FeS2/Fe2O3. Based on the iron and in-situ generated H2O2, •OH was produced through a photo-Fenton reaction. Furthermore, h+, e-, and •O2−, which were generated through the photo-catalytic activation of FeS2/Fe2O3, also played a certain role in the degradation of carbamazepine (CBZ). Therefore, the synergistic photo-Fenton and photo-catalytic reaction improved the degradation of CBZ, with the degradation efficiencies of 86%, 62%, and 68% in FeS2/Fe2O3/TA, FeS2/Fe2O3/AA, and FeS2/Fe2O3/CA systems, respectively. This investigation provides an innovative strategy for the removal of organic pollutants using natural minerals.

Anodic TiO2 nanotube: influence of annealing temperature on the photocatalytic degradation of carbamazepine

Anodic TiO2 nanotube: influence of annealing temperature on the photocatalytic degradation of carbamazepine

Degradation of Carbamazepine from Aqueous Solutions via TiO2-Assisted Photo Catalyze.

Photocatalytic degradation of carbamazepine (CBZ) from spiked aqueous solutions, via a UV/TiO2 system, was investigated, and the optimum photocatalyst type (P25 Degussa) and dose (500 mg/L), as well as irradiation time (45 min), were established. The degradation process kinetics was studied, and a degradation rate constant of 3.14 × 10−5 M min−1 was calculated for CBZ, using the Langmuir–Hinshelwood equation. Experiments performed in the presence of scavengers showed that the main reactive species involved in the degradation process are holes and free hydroxyl radicals; superoxide radicals also play a role in CBZ degradation. Eight transformation products of CBZ were identified, and a possible degradation pathway, consisting of four routes, was proposed. Toxicity and genotoxicity tests were also performed for both untreated and treated CBZ solutions, proving that the use of a UV/TiO2 system represents a suitable treatment approach for aqueous systems with CBZ content.

CNTs/MOF-808 painted plates for extended treatment of pharmaceutical and agrochemical wastewaters in a novel photocatalytic reactor

The photocatalysis technology suffers a yawning gap between the extravagant academic studies and substantive implementation. The viability of photocatalysis may thrive by steering the research towards the reactor design, fixed photocatalysts, real wastes, and cost estimation. Herein, we prepared novel nanocomposites of metal-organic framework-808 (MOF-808) and carbon nanotubes (CNTs) with different ratios to employ them in the photocatalytic degradation of carbamazepine (CBZ) and diazinon. A photocatalytic reactor with CNTs/MOF-808 painted plates was employed to use the catalyst in a reusable form. Various analyses were conducted to study the morphology and composition of CNTs/MOF-808 composites. The response surface methodology (RSM) was used for the optimizing the operational parameters. The reuse of the coated plates in continuous cycles indicated the proper stability of CNTs/MOF-808. For instance, the degradation of diazinon was 99.7%, 96.3%, 94.8%, 93.5% and 92.1% for five cycles. The degradation mechanism and the oxidation pathways have been intensively investigated. Furthermore, the reactor was employed for the treatment of real agrochemical and pharmaceutical liquid wastes showing a reduction in the total organic carbon (TOC) by 93% and 76%, respectively. A cost-estimation study implies that a large-scale photocatalytic system costs 2.523 $/m3 including the amortization and operating costs.

Photocatalytic degradation of carbamazepine using ozonation and photocatalytic ozonation with TiO2 and WO3

AbstractOzonation, TiO2 photocatalytic ozonation (PCO) and WO3 PCO were used to demonstrate the removal of carbamazepine (CBZ), an antiepileptic drug commonly found in water bodies. The experiment was carried out in a lab-scale reactor (500 mL) at pH 7, CBZ concentration 1 mg/L and 0.25 g/L catalyst dose. The mixture was stirred in the dark for 30 minutes to achieve adsorption equilibrium. A UV and visible light source of 8 watt was used to photoactivate TiO2 and WO3. Ozonation alone using an ozone dose of 10 mg/hour was found to be very effective for CBZ removal. In all the processes investigated, CBZ was easily removed while the removal of by-products varied depending on the reaction pathway. The mineralization efficiencies (TOC removal) for complete by-products removal using ozonation, TiO2 PCO and WO3 PCO were 95, 73 and 62% respectively. TiO2 PCO performed better than WO3 PCO in achieving complete mineralization, but it would not be a sustainable solution considering the costs of UV lamps, harmful UV rays and toxicity of TiO2. The removal efficiency of WO3 PCO can be increased by increasing the ozone dose and duration of treatment.

Synthesis of Fe- and Co-Doped TiO2 with Improved Photocatalytic Activity Under Visible Irradiation Toward Carbamazepine Degradation.

Pure TiO2 and Fe- and Co-doped TiO2 nanoparticles (NPs) as photocatalysts were synthesized using wet chemical methods (sol-gel + precipitation). Their crystalline structure and optical properties were analyzed using X-ray diffraction (XRD), Raman spectroscopy and Fourier-transform infrared (FTIR) spectroscopy, ultraviolet-visible light (UV-Vis) diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy. The photocatalytic activity of the synthesized nanoparticles was evaluated through degradation of carbamazepine (CBZ) under UV-A and visible-light irradiations. The XRD and Raman analyses revealed that all synthesized nanomaterials showed only the anatase phase. The DRS results showed that the absorption edge was blue-shifted for Fe-doped TiO2 NPs. The decrease in charge recombination was evidenced from the PL investigation for both Co-doped and Fe-doped TiO2 nanomaterials. An enhancement in photocatalytic degradation of carbamazepine in aqueous suspension under both UV-A light and visible-light irradiations was observed for Fe-doped Titania NPs by comparison with pure TiO2. These results suggest that the doping cations could suppress the electron/hole recombination. Therefore, the photocatalytic activity of TiO2-based nanomaterials was enhanced.

Effects of inorganic ions on the photocatalytic degradation of carbamazepine

Abstract Carbamazepine (CBZ) is a typical class of pharmaceuticals and personal care products (PPCPs), and is a serious threat to the environment and human health. Photocatalytic degradation is an efficient technology to remove CBZ. However, the present work focused mainly on the improvement of photocatalytic degradation performance. The information about the effects of inorganic ions on the photocatalytic degradation activity of environmental pollutants is still scarce. This study systematically investigated the effects of inorganic ions on the photocatalytic degradation of CBZ in view of the practical applications. The addition of inorganic anions showed a negative effect on photocatalytic degradation of CBZ with the order of inhibition effects of HCO3− > Cl− > NO3−. This was due to the quenching effects of hydroxyl radicals or holes, which decreased the photocatalytic degradation of CBZ. The presence of Al3+ could adsorb on the surface of a photocatalyst to shield the active site, resulting in the decreased CBZ degradation, while coexistence of Ca2+ significantly promoted the photocatalytic degradation of CBZ owing to the enhanced CBZ adsorption. Mg2+ showed concentration and time-dependent effects (suppression or promotion) on the photocatalytic degradation of CBZ.

Fabrication of Sb2O3/PbO photocatalyst for the UV/PMS assisted degradation of carbamazepine from synthetic wastewater

Photocatalytic degradation of carbamazepine (CBZ) was investigated by hydrothermally synthesized antimony trioxide (Sb2O3)/lead oxide (PbO) photocatalyst. The photocatalyst synthesized with different ratio of Sb2O3 and PbO viz. 1:1, 2:1, 3:1, 1:2, and 1:3. Photocatalyst with 3:1 ratio of Sb2O3 and PbO showed the best photocatalytic activity towards CBZ. Transmission electron microscopy (TEM) analysis suggested that the particle size increased by increasing PbO ratio in the catalyst. It was observed that Sb2O3 synthesis with PbO showed less band gap energy in comparison to Sb2O3. The Brunauer–Emmer–Teller (BET) surface area of the Sb2O3/PbO (3:1) was determined to be 4.78 m2 g−1. In absence of catalyst, very low degradation of CBZ was achieved, while significant enhancement in CBZ degradation was observed in presence of the synthesized catalyst. CBZ degradation followed the pseudo first-order kinetics with rate constant of 0.016 min−1. Increased degradation rate was recorded when peroxymonosulfate (PMS) was used with UV/Sb2O3/PbO. Active species trapping experiment revealed that in CBZ degradation, O2– radical produced by synthesized catalysts played a major role. In presence of PMS, generation of SO4-∙ radical enhanced the catalytic activity of synthesized catalyst.

Photocatalytic degradation behavior of multiple xenobiotics using MOCVD synthesized ZnO nanowires

In this study, we investigated the beneficial properties of ZnO nanowires grown via a MOCVD (Metal Organic Chemical Vapor Deposition) process for the photocatalytic treatment of a solution containing seven xenobiotics that are commonly found in waste or surface water. A physicochemical characterization of the ZnO nanowires was performed to highlight the advantages of the high-temperature gas-phase MOCVD process for the synthesis of photocatalytic ZnO materials. In addition, the photocatalytic degradation of carbamazepine, diclofenac, lidocaine, metoprolol, propranolol, sulfadimidine and atenolol was studied for the first time using a one-step experiment under a low power 365nm UV light (2.28mWcm−2). We determined the fast photodegradation kinetics of all of the xenobiotics present in the solution. These results support the use of photocatalytic methods for the removal and degradation of xenobiotics.

Photocatalytic oxidation of trace carbamazepine in aqueous solution by visible-light-driven Znln2S4: Performance and mechanism

In this work, visible-light-driven Znln2S4 photocatalyst (band gap 1.98 eV, absorption wavelength 300–600 nm) was synthesized by a facile hydrothermal method for photocatalytic degradation of trace pharmaceutical carbamazepine (CBZ) in aqueous solution, and characterized by UV–Vis diffusive reflectance spectroscopy, BET, SEM and XRD, respectively. It demonstrated that a complete degradation of CBZ was achieved with an optimal Znln2S4 dosage of 30 mg/L under a 100 W iodine-gallium lamp irradiation of 20 min, which afforded the reaction rate constant and half-life being respectively 10.44 times higher and 1/8 less than that obtained by a direct photolysis without Znln2S4 photocatalyst. A negligible influence of initial solution pH on photocatalytic degradation of CBZ was confirmed under the given pH range of 5.0–9.0. The degradation efficiency of CBZ was slightly decreased from 91% to 84% after five consecutive cycles. Hydroxy radical (·OH) plays an important role in CBZ degradation accompanying a synergistic effect of photogenerated hole (h+) and O2− active species during reaction. Further, 44 intermediates were detected by LCMS-IT-TOF technique and tentative degrading pathways were proposed on the basis of the experimental results.

Synthesis, characterization and performance of visible light active C-TiO2 for pharmaceutical photodegradation

The present paper deals with photocatalytic degradation of carbamazepine and diclofenac by using a modified catalyst with band gap excitations in visible light. The C-doped TiO2 was synthesized using a microwave digestion method from titanium oxyacetylacetate with glucose as the carbon source. The synthesized catalyst was then characterized using Scanning Electron microscopy (SEM), X-ray Diffractometry (XRD), X-ray photoelectron spectroscopy (XPS) and UV-VIS-NIR spectrophotometer. The TiO2 present was in anatase phase and showed significant absorption in visible region. The catalyst was tested for the degradation of carbamazepine and diclofenac under visible light, where complete removal was achieved and the reaction followed first order kinetics. System parameters like catalyst and pollutant concentration, light intensity and time of reaction, were optimized using response surface methodology. In optimum conditions (catalyst concentration of 244mg/L and light intensity of 7715lx) 99% removal was achieved.

Photocatalytic degradation of carbamazepine and three derivatives using TiO2 and ZnO: Effect of pH, ionic strength, and natural organic matter

Removal of pharmaceuticals (PhCs) by photocatalysis is a promising avenue in water treatment. The efficiency of these treatments on PhC derivatives compared to their parent molecules remains poorly documented. The present study investigates the efficiency of photodegradation catalyzed by TiO2 and ZnO nanoparticles on the removal of carbamazepine (CBZ) and three of its derivatives; carbamazepine epoxide (CBZ-E), acridine (AI), and acridone (AO). The effects of environmental parameters such as pH, ionic strength, and natural organic matter content on photodegradation efficiency (transformation after 6h and kinetics) were tested. We report that the efficiency of the catalysts (TiO2 and ZnO) can be very different when comparing CBZ and its derivatives (CBZ-E, AI and AO). TiO2 was more efficient than ZnO at degrading CBZ and CBZ-E. For AI and AO, no significant differences were observed between the two catalysts. We also report that environmental parameters have contrasting effects on the efficiency of the photodegradation of CBZ compared to its derivatives. Changing pH and organic matter content had the most contrasted effects; the photodegradation of CBZ and CBZ-E was significantly affected by pH (especially in presence of TiO2 NPs) and by the presence of natural organic matter. In contrast, the photodegradation of AI and AO was not affected by pH and organic matter. Only the photodegradation of CBZ was clearly affected by IS and solely at very high IS (1M). Overall, our results highlight that TiO2 and ZnO catalysts present contrasted efficiency on the removal of CBZ when compared to its derivatives (CBZ-E, AI and AO). Our results also show that the effect of environmental parameters on the efficiency of the photodegradation of CBZ derivatives cannot be predicted based on the behavior of the parent molecule (CBZ).

The photocatalytic degradation of carbamazepine and prediction by artificial neural networks

The three layer artificial neural network model was applied to predict the degradation efficiency for carbamazepine in photocatalytic oxidation under UV radiation. Titania–zirconia was employed as a catalyst for the photooxidation. The catalyst was prepared using titanium isopropoxide and zirconium oxychloride by sol–gel method and characterized by transmission electron microscopy and BET analysis. Different process parameters such as, initial concentration of carbamazepine, pH of the solution, catalyst concentration and time of UV irradiation were employed as the input to the artificial neural network model and the output of the network was degradation efficiency of carbamazepine. The multilayer feed-forward networks with the Levenberg–Marquardt (trainlm) backpropagation training algorithm was used for the network training. The smallest mean square error was obtained for three-layer network with ‘logsig’ transfer function and five neurons in the hidden layer gave optimal results. A comparison between the predicted values and selective experimental data of degradation efficiency showed a high correlation coefficient (R2) of 0.997.

Photocatalytic degradation of carbamazepine by tailored BiPO4: efficiency, intermediates and pathway

This study firstly explored the photodegradation of carbamazepine, one of the most frequently detected pharmaceuticals, with tailored BiPO4 nanomaterials. BiPO4 was synthesized with a hydrothermal method. The physicochemical properties of the obtained samples were characterized and the results indicated that both the hydrothermal temperature and reaction time influenced the phase, morphology and optical properties of the BiPO4 catalysts, which may further determine their specific photocatalytic performances. The intrinsic microstructure and optical properties reflected the crystal properties of the catalysts to some extent. The BiPO4 prepared at 180°C for 72h (BPO-180-72) displayed the best photocatalytic activity under UV irradiation, during which carbamazepine was nearly completely eliminated from ultrapure water after 60min irradiation. The good photocatalytic activity was ascribed to the synergistic effect of monoclinic phase and relatively ordered morphology of the resulting BiPO4. Particularly, the monoclinic phase was firstly proved to be more active than the hexagonal phase for BiPO4 samples. BPO-180-72 removed approximately 72.4% of carbamazepine from lab-prepared simulated wastewater after 60min irradiation, suggesting the potential application of this material in wastewater treatment. Ten reaction intermediate products were observed and identified by HPLC–MS/MS, and a tentative reaction pathway was proposed. Results indicated that photogenerated holes and hydroxyl radicals were the main reactive species for the photodegradation of carbamazepine in the system.

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

The photocatalytic degradation of Carbamazepine (CBZ), 5H-dibenzo[b,f]azepine-5-carboxamide, under near UV–Vis and UV irradiation is studied using P25, synthesized TiO2 (anatase and rutile), mechanical mixtures and composites of oxidized-multi-walled-carbon-nanotube:anatase, and ZnO suspensions as catalyst, to identify intermediates, and to elucidate its degradation mechanism. Factors affecting the kinetics of the process, such as the type and load of photocatalyst, and the presence of dissolved O2 or addition of co-oxidants (H2O2), have been compared. Optimal conditions for degradation were obtained using P25 (0.5g/L), 5mM of H2O2 or 50% O2 (v/v), with rate constants ca. 0.3144min−1 and 0.2005min−1, respectively. Complete removal of CBZ was achieved, showing the efficiency of the photocatalytic process. Ten photoproducts of CBZ were assigned by using high-resolution mass spectrometry, the most important of which identified as 10,11-dihydro-CBZ-10,11-epoxide, in accordance with the literature. The reaction mechanism includes previous proposals, and accounts for the pathways giving rise to the identified photoproducts.

Photocatalytic degradation of clofibric acid, carbamazepine and iomeprol using conglomerated TiO2 and activated carbon in aqueous suspension

The combination of powdered activated carbon (PAC) and TiO(2) has been tested for synergistic/antagonistic effects in the photocatalytic degradation of carbamazepine, clofibric acid and iomeprol. Synergistic effects are thought to be caused by rapid adsorption on the PAC surface followed by diffusion to the TiO(2) surface and photocatalytic degradation. The Freundlich constant K(F) was used for comparing the sorption properties of the three substances and it was found that K(F) for clofibric acid was 3 times lower than for carbamazepine and iomeprol, regardless of the kind of PAC used. A PAC with a distinct tendency to form conglomerates was selected so that a high percentage of the PAC surface was in direct proximity to the TiO(2) surface. The photocatalytic degradation of the pharmaceutically active compounds studied followed pseudo-first order kinetics. Synergistic effects only occurred for clofibric acid (factor 1.5) and an inverse relationship between adsorption affinity and synergistic effects was found. High affinity of the target substances to the PAC surface seemed to be counterproductive for the photocatalytic degradation.

Photochemischer und photokatalytischer Abbau von Carbamazepin, Clofibrinsäure, Iomeprol und Iopromid

Photochemical and Photocatalytic Degradation of Carbamazepine, Clofibric Acid, Iomeprol and Iopromide