Decomposition Of Carbamazepine Research Articles

The efficient abatement of contaminants of emerging concern by LED-UV275nm/electrochemical chlorine for wastewater reuse: kinetics, degradation pathways, and cytotoxicity

Treating wastewater to augment surface water can be a practicable solution to water scarcity, while the residual contaminants of emerging concern (CECs) and inorganic ions put forward new requirements to the treatment methods. Electrochemical chlorine process (EC/Cl2) utilizes the remaining Cl− in wastewater to generate free chlorine and radicals, which could be further improved in conjunction with LED UV275nm irradiation (UV-EC/Cl2). Compared to UV only and EC/Cl2, UV-EC/Cl2 could effectively decompose the selected CECs at higher rates due to the much higher yield of reactive chlorine species (Cl•, ClO•, and Cl2•−). A MATLAB R2021a programming method was developed to estimate the order of magnitude of these radicals, and Cl2•− was the most abundant radical. In the UV-EC/Cl2 system, CECs with phenolic or aniline moieties were mainly degraded by electrochemical oxidation (EC), ClO•, and Cl2•−; and the CECs with weakly electron-donating moieties were predominately decomposed by EC, •OH, and Cl•. The degradation pathways of levofloxacin, diclofenac, carbamazepine (CBZ), and ibuprofen were proposed according to the transformation products (TPs) detected by LC/Q-TOF-MS. Moreover, the cytotoxicity of spiked CBZ in real water samples, that were discharged to surface water, was significantly reduced by UV-EC/Cl2. Interestingly, the electrical energy per order (EE/O) for CBZ decomposition by LED UV275nm-EC/Cl2 (1.46 kWh m−3 order−1) is lower than that by UV/Cl2, EC/Cl2, and UV254nm-EC/Cl2. The results indicate that UV-EC/Cl2 could be used as a promising method to remediate CECs during the tertiary treatment and reuse of wastewater for augmenting surface water.

Efficient degradation of carbamazepine in a neutral sonochemical FeS/persulfate system based on the enhanced heterogeneous-homogeneous sulfur-iron cycle

In this study, a novel ultrasound enhanced FeS/persulfate Fenton-like system (US/FeS/PDS) was developed for the synergistic degradation of a typical drug carbamazepine (CBZ) under neutral circumstances. Factors such as FeS dosage, PDS dosage, initial pH and temperature, as well as coexisting anions were investigated. High dosages of FeS and PDS, elevated temperature and acidic circumstances were favorable for the oxidation of CBZ. Presence of HCO3− strongly inhibited the CBZ degradation in the US/FeS/PDS system, while slight suppression was observed with either NO3− or Cl−. Seven intermediates were identified as the products from the decomposition of CBZ by hydroxyl radicals (OH·) and sulfate radicals (SO4−·). Time-dependent radical examination indicated that homogeneous OH· and SO4−· would contribute to the CBZ removal from 22.6 to 34.7% and 12.9 to 50.5%, respectively, while the contribution of solid-liquid interfacial radicals decreased from 64.5 to 20.2%. Meanwhile, the oxidation of S2− occurred concurrently with reduction of Fe(III) to Fe(II). The reaction mechanism in the US/FeS/PDS system was proposed based on the sonochemical heterogeneous-homogeneous sulfur-iron cycle in the US/FeS/PDS system. US would firstly enhance the interfacial sulfur-iron electron transfer and the disintegration of the passivation layer, and then lead to the overall improvement in both interfacial and bulk sulfur-iron cycle, as well as the degradation of CBZ.

Heat capacities of selected active pharmaceutical ingredients

Condensed-phase heat capacities of selected pharmaceutical active pharmaceutical ingredients (APIs), namely (RS)-ibuprofen (CAS RN: 15687-27-1), (S)-ibuprofen (CAS RN: 51146-56-6), (S)-naproxen (CAS RN: 22204-53-1), indomethacin (CAS RN: 53-86-1), and carbamazepine (CAS RN: 298-46-4), were determined using Tian-Calvet calorimetry and power-compensated differential scanning calorimetry in the temperature range 216 to 471 K. In most cases, previously published heat capacities of the studied APIs are in significant disagreement both with each other and our measurements. By analyzing the literature values, many previously published data sets were shown to be erroneous. The heat capacities of supercooled liquid, an important parameter in the modeling of API solubility, were also measured in a wide temperature range when feasible. The phase behavior study of carbamazepine suggests that its thermal stability is lower than previously thought, which is in accordance with the most recent studies on carbamazepine decomposition. This work significantly extends the availability of reliable API heat capacity data for clearly defined polymorphic forms and liquid phase.

Enhanced photocatalytic activity of accordion-like layered Ti3C2 (MXene) coupled with Fe-modified decahedral anatase particles exposing {1 0 1} and {0 0 1} facets

New composites consisting of decahedral anatase particles exposing {001} and {101} facets coupled with accordion-like layered Ti3C2 with boosted photocatalytic activity towards phenol and carbamazepine degradation were investigated. The photocatalysts were characterized with X-ray diffraction (XRD), diffuse reflectance spectroscopy (DR/UV–Vis), Brunauer-Emmett-Teller (BET) specific surface area, Raman spectroscopy, scanning electron microscopy (SEM), electron paramagnetic resonance (EPR) spectroscopy, emission spectroscopy, luminescence decay analysis, electrochemical impedance spectroscopy (EIS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and electrophoretic mobility measurements. The effect of hydrothermal reaction parameters on physicochemical, structural, and photocatalytic properties was studied. In all photodegradation processes, ortho-hydroxyphenol and para-hydroxyphenol were detected as the first intermediates of phenol decomposition. For the TiO2/Ti3C2(140,12) sample containing VTi, a higher concentration of para-hydroxyphenol than ortho-hydroxyphenol was observed, whereas for sample TiO2/Ti3C2(220,24) higher concentration of ortho-hydroxyphenol was noticed. The formation of surface heterojunction between {101} and {001} facets of decahedral anatase particles grown on Ti3C2 surface led to improved photoelectron transfer and enhanced photocatalytic activity towards degradation of carbamazepine - non-biodegradable and susceptible to bioaccumulation in living organisms commonly used pharmaceutical agent. Moreover, modification of TiO2/Ti3C2 surface with iron by magnetron sputtering deposition markedly improved photocatalytic activity in carbamazepine decomposition, with nearly 100% degradation in 60 min of irradiation under simulated solar light.

Electro-oxidation and solar electro-oxidation of commercial carbamazepine: effect of the support electrolyte

ABSTRACT Carbamazepine (CBZ) is an anticonvulsant pharmaceutical that is resistant to photodegradation and biodegradation in conventional wastewater treatment plants. In this research, the degradation of commercial CBZ was studied using a boron-doped diamond-Fe system in continuous flow. A response surface model was created to determine the contributions of the current intensity (0.39, 0.50, 0.75, 1.00, and 1.10 A) or current density (1.69, 2.16, 3.25, 4.33, and 4.76 mA/cm2, respectively), support electrolyte (NaCl and CaCl2), and initial CBZ concentration ([CBZ]0) (0.1, 1.0, 5.5, 10.0, and 11.8 mg/L). The highest CBZ removal (%) was achieved with NaCl as a support electrolyte at a current intensity of 0.64 A (2.77 mA/cm2) and [CBZ]0 of 4.5 mg/L at a neutral pH (6–7) and a treatment time of 120 min. The electro-oxidation (EO) process achieved a removal efficiency of 77.25%, whereas solar EO removed 90.77% of CBZ in the presence of ultraviolet radiation (536.37 W/m2). CBZ degradation was fitted to the Behnajady–Modirshahla–Ghanbery kinetic model with constant values of 1/m = 0.31 and 1/b = 0.93, thereby indicating the fast decomposition of CBZ. The toxicity was significantly reduced in the effluent.

Enhanced thermal stability of carbamazepine obtained by fast heating, hydration and re-crystallization from organic solvent solutions: A DSC and HPLC study

Although drugs are usually stored at room temperature, their thermal stability up to the melting point is often required for processing such as quenching or hot-melt extrusion. It especially concerns substances which have poor water solubility, as these techniques are used to either assess the glass forming ability or to prepare solid dispersions with the aim to enhance dissolution rate and bioavailability. Carbamazepine (CBZ), an antiepileptic drug, is an example of active pharmaceutical ingredient which shows both limited solubility in water and decomposition below melting point. This paper suggests and discusses different ways to enhance CBZ thermal stability, namely fast heating of the sample, hydration and re-crystallization from organic solvents (ethanol, acetone and dichloromethane). The presence of a model degradation product, i.e. iminostilbene is evaluated using differential scanning calorimetry and high-performance liquid chromatography. Obtained results show that all three proposed approaches are able to reduce the degree of CBZ thermal degradation, however none of them entirely stops the decomposition of CBZ in the vicinity of the melting point.

Improving ozonation to remove carbamazepine through ozone-assisted catalysis using different NiO concentrations.

The carbamazepine (CBZ) abatement is herein evaluated using catalytic ozonation at different NiO concentrations as catalyst: 100, 300, and 500mgL-1, revealing its total destruction after 5min of reaction either by conventional or catalytic ozonation. The NiO incorporation in the reactor does not increase the destruction rate, but the catalyst presence enhances the partial mineralization of the contaminant by conversion into oxalic and formic acids and the removal of total organic carbon (TOC) associated with the formation of oxidant species such as hydroxyl radical. Evidence for this behavior is the accumulation rate of the above acids which rise proportionally to the NiO concentration. The highest NiO concentration (500mgL-1) reached a maximum TOC removal of 79.2%, which exceeds by 50% the outcome of the conventional treatment. The accumulation-decomposition profiles of oxalic and formic acids suggest the occurrence of simultaneous reaction mechanisms (hydroxyl radicals and complex formations) on the catalyst during CBZ ozonation. According to XPS analysis, the presence of nitrogen species in the NiO-ozonated was attributable to byproducts of CBZ decomposition. The toxicity bioassay based on Lactuca sativa seeds demonstrate that ozonated samples attained similar plant germination than the reference substance (water) after 120min of treatment. This result is comparable with or without the catalyst presence, indicating the formation of non-toxic accumulated byproducts at the end of the ozonation reaction.

Effect of alpha-hydroxy acids on transformation products formation and degradation mechanisms of carbamazepine by UV/H2O2 process

The role of dissolved organic matters (DOM) in the matrix of water on the degradation of refractory pharmaceutical has aroused broad concerns. However, The effect of alpha-hydroxy acids as vulnerable aliphatic acids in the water on the degradation of Carbamazepine (CBZ) has been lack of research. The decomposition kinetics and transformation products (TPs) of CBZ by UV/H2O2 process were studied in the existence of glycolic acid (GA) and lactic acid (LA) and the degradation pathways were proposed. Both GA and LA had significantly negative effects on the decomposition kinetics and mineralization of CBZ by UV/H2O2 process. The declination of steady-state OH concentration in the presence of GA and LA justified the negative effects. GA was demonstrated to be stronger at scavenging and competing OH with CBZ, compared with LA, with the rate constant of slightly less than the common OH scavenger methanol. One-step dosing mode of H2O2 was better than multi-step dosing mode for CBZ decomposition, especially in the presence of GA and LA. The identification of TP253a, TP253b, TP271a, TP271b, TP226, and TP180 in the absence and presence of GA and LA were performed by HPLC-MS/MS and two main degradation pathways were presented. Except for TP271a and TP271b, GA and LA retarded the abundance peaks of other four TPs, of which the formation kinetics rates and decay kinetics rates were negatively affected. Tailing peaks of all TPs caused by GA and LA inevitably resulted in the toxicity of the treated effluent of UV/H2O2 process even when CBZ was decomposed completely. Therefore, alpha-hydroxy acids play important roles in determining the fate and transformation of refractory pharmaceuticals in AOPs treatment.

In situ growth of Ag-SnO2 quantum dots on silver phosphate for photocatalytic degradation of carbamazepine: Performance, mechanism and intermediates toxicity assessment

The occurrence of carbamazepine (CBZ) in environments poses a potential risk to aquatic life and exhibits growth inhibition of human embryonic cells. In this work, for the first time a series of Ag-SnO2 quantum dots (QDs)/silver phosphate (AgSn/AgP) composites were synthesized and used as photocatalysts for CBZ degradation. The obtained AgSn/AgP composites showed superior photodegradation efficiency for CBZ removal. The degradation rate constant of 10AgSn/AgP (with 10 wt% of Ag-SnO2 QDs) was almost 8.5, 5.7, 5.7, and 1.9 times as that of Ag-SnO2 QDs, Ag3PO4, Ag/Ag3PO4, and SnO2 QDs/Ag3PO4, respectively. The improved photocatalytic activity could be primarily ascribed to the improved charge separation through a collaborative effect of Ag-SnO2 QDs and Ag3PO4, and in situ photoreduced metallic silver. Electron spin resonance (ESR) measurement and radical trapping experiments suggested that holes (h+), (superoxideradical) ·O2− and (hydroxylradical) ·OH corporately participated in the decomposition of CBZ. Moreover, a reasonable mechanism for photocatalytic degradation of CBZ over 10AgSn/AgP composites was tentatively proposed. Additionally, eight degradation intermediates were determined by liquid chromatography-mass spectrometry (LC-MS). Toxicity evaluation using the Ecological Structure Activity Relationships (ECOSAR) program revealed that the toxicity of most photodegradation intermediates were much lower than that of the parent compound CBZ. This work not only provides a new technique for preparing Ag3PO4-based photocatalysts with high activity, but also demonstrates that 10AgSn/AgP could be a promising photocatalyst for treating water and wastewaters containing CBZ.

Effective mineralization of anti-epilepsy drug carbamazepine in aqueous solution by simultaneously electro-generated H2O2/O3 process

A novel electro-generated hydroxyl radical (OH) technique was constructed to effectively degrade the anti-epilepsy carbamazepine (CBZ) representing typical recalcitrant pharmaceutical only through electrochemical method as an alterative peroxone process. The technique involves simultaneously electro-generated H2O2 using a carbon-polytetrafluoroethylene (C/PTFE) cathode to reduce the injected O2 and electro-generated O3 using H2O oxidation with a Ti mesh/PbO2 anode in membrane electrode assembly (MEA). The significant OH formation through the synergetic system of in-situ produced H2O2 and O3 electrochemically could achieved carbamazepine decomposition and total organic carbon (TOC) removal as compared to electro-generated H2O2 or O3 alone. The main influential factors including current density and aqueous pH were investigated to reveal their effect on CBZ removal efficiencies. Under optimal parameters, CBZ decomposition and TOC mineralization could be completely accomplished after 10 min and 90 min electrolysis, respectively. According to intermediates distribution (e.g. hydroxylated CBZ, phenolics, and carboxylic acids) identified by HPLC-MS/MS, the degradation pathways were proposed for CBZ removal by the synergetic system of C/PTFE-O2 and MEA. The above results indicated that this electrochemically synergetic system is a potential technique to further purify the water contaminated by recalcitrant pharmaceuticals.

Heterostructural TiO2/Ti3C2Tx (MXene) for photocatalytic degradation of antiepileptic drug carbamazepine

A simple hydrothermal treatment process was used for the fabrication of a Ti3C2Tx (MXene) nanosheet-based hybrid photocatalyst. The chemical composition of the MXene and its derivatives (nanosize {0 0 1} facets of TiO2 in Ti3C2Tx (001-T/MX)), as well as the structural properties and morphology of the as-prepared photocatalyst, were well characterised. The heterostructure of the as-prepared photocatalyst was obtained by controlled oxidation action via the Schottky junction formed between TiO2-MXene interfaces. The adsorption/photocatalytic degradation abilities of the pristine MXene and the as-synthesised 001-T/MX nanocomposite for carbamazepine (CBZ) were investigated. The determined Kapp value of CBZ under ultraviolet light was 0.0304 min−1, higher than that under natural solar light, and the degradation capacity was strongly controlled under acidic conditions (pH 3.0–5.0). During the photocatalytic degradation, OH and O2 attacked the CBZ molecule; detailed degradation pathways were proposed accordingly. The novel heterojunction 001-T/MX exhibited excellent applicability for CBZ decomposition.

Titania-coated nanosilica–cobalt ferrite composites: Structure and photocatalytic activity

Abstract In this study, a set of CoFe 2 O 4 /SiO 2 /TiO 2 nanocomposites was synthesized. The total concentration of metals (Co + Fe) was varied from 3 to 9 mmol with respect to 1 g of SiO 2 . Titania was formed in two concentrations — 2 and 4 mmol/g. The structure of the samples was analyzed by application of XRD, UV–vis spectroscopy, magnetometry, SEM, low-temperature nitrogen adsorption–desorption and Mossbauer spectroscopy. Photocatalytic degradation of an organic model compound – carbamazepine (CBZ) – was studied in the presence of the nanocomposites under ultraviolet irradiation ( λ = 254 nm) in a batch reactor. Two types of media (distilled and tap water) were used. The X-ray diffraction patterns demonstrate the formation of CoFe 2 O 4 and TiO 2 (anatase). The studied materials reveal a better activity than commercial sample of P25 (Evonik) during degradation of carbamazepine (CBZ). It has been found that the type of water medium affects the CBZ decomposition differently: there is residual CBZ observed in distilled water in 60 min of treatment. Contrastingly, in tap water the total decomposition of CBZ took place. This may be due to the occurrence of Fe 3+ ions which stimulate the formation of active sites of chlorine dissolved in tap water.

Transformation Pathways of the Recalcitrant Pharmaceutical Compound Carbamazepine by the White-Rot Fungus Pleurotus ostreatus: Effects of Growth Conditions.

The widely used anticonvulsant pharmaceutical carbamazepine is recalcitrant in many environmental niches and thus poses a challenge in wastewater treatment. We followed the decomposition of carbamazepine by the white-rot fungus Pleurotus ostreatus in liquid culture compared to solid-state fermentation on lignocellulosic substrate where different enzymatic systems are active. Carbamazepine metabolites were identified using liquid chromatography-high-resolution mass spectrometry (LC-Q-TOF-MS). In liquid culture, carbamazepine was only transformed to 10,11-epoxy carbamazepine and 10,11-dihydroxy carbamazepine as a dead-end product. During solid-state fermentation, carbamazepine metabolism resulted in the generation of an additional 22 transformation products, some of which are toxic. Under solid-state-fermentation conditions, 10,11-epoxy carbamazepine was further metabolized via acridine and 10,11-dihydroxy carbamazepine pathways. The latter was further metabolized via five subpathways. When (14)C-carbonyl-labeled carbamazepine was used as the substrate, (14)C-CO2 release amounted to 17.4% of the initial radioactivity after 63 days of incubation. The proposed pathways were validated using metabolites (10,11-epoxy carbamazepine, 10,11-dihydroxy carbamazepine, and acridine) as primary substrates and following their fate at different time points. This work highlights the effect of growth conditions on the transformation pathways of xenobiotics. A better understanding of the fate of pollutants during bioremediation treatments is important for establishment of such technologies.

Aquatic photolysis of carbamazepine by UV/H2O2 and UV/Fe(II) processes

In this work, the degradation of carbamazepine (CBZ) in water by UV/H2O2 and UV/Fe(II), two UV-based photolysis processes, was investigated. The addition of H2O2 and Fe(II) significantly improved the CBZ decomposition rate relevant to UV treatment alone. For UV/H2O2 photolysis, CBZ photodegradation followed pseudo-first-order kinetics. The rate of CBZ degradation increased with the increase of H2O2 concentrations and the decrease of initial CBZ concentrations. CBZ oxidation rates in sea water and surface water were lower than that in pure water and the maximum CBZ degradation occurred at pH 7. Additionally, both Cl− and HCO3 − could inhibit the CBZ decomposition in UV/H2O2 photolysis. For the UV/Fe(II) system, CBZ photodegradation also showed pseudo-first-order kinetics. The results showed that the degradation increased as the initial Fe(II) concentration increased up to a certain limit at which Fe(II) reduced the degradation by scavenging the $$\cdot {\text{OH}}$$ . O2 was favorable for CBZ degradation in UV/Fe(II) process. Finally, major degradation products of CBZ, including degradation intermediates, organic acids, and inorganic ions were detected by LC/MS/MS and IC. Based on the LC/MS/MS and IC analysis, the possible degradation pathways of CBZ photolysis were proposed. Results demonstrated that UV/H2O2 and UV/Fe(II) were both potential technologies for water treatment containing CBZ. However, considering the energy consumption, UV/Fe(II) was more efficient than UV/H2O2 process for CBZ degradation.

Thermally activated persulfate (TAP) oxidation of antiepileptic drug carbamazepine in water

Sulfate radicals-based advanced oxidation processes have been applied in water treatment and in situ chemical oxidation. Batch experiments were conducted to investigate the influencing factors including persulfate dosage, initial carbamazepine (CBZ) concentrations, solution pH, coexisting inorganic anions and cations on the decomposition of CBZ using thermally activated persulfate (TAP) technology. The results showed that TAP oxidation was efficient process for the CBZ degradation in water. The generation of sulfate radicals was accounted for the CBZ degradation in TAP system. The CBZ degradation rate constant increased as persulfate dosage increased and decreased as the initial CBZ concentrations increased. The CBZ decomposition rate decreased with the increasing pH and the best degradation occurred at pH 3. The exception was the strong alkaline condition under which a higher CBZ degradation performance was achieved. Coexisting inorganic anions slowed down the CBZ degradation to different degrees and the inhibiting effect abided by the following order: CO32->HCO3->Cl->SO42->NO3-. In contrast, coexisting cations could significantly enhance the CBZ degradation, and the promoting effect was in the order of Fe2+>Cu2+>Fe3+. In this study, six major intermediate products were generated during the TAP oxidation.