Initial Carbamazepine Concentration Research Articles

Enhanced Selective Degradation of Pharmaceutical and Personal Care Products by β-Cyclodextrin-Decorated ZIF-67 Nanocomposites in Reclaimed Water.

A peroxymonosulfate oxidation system was developed via modification of β-cyclodextrin (β-CD) on the surface of Fe2+-doped ZIF-67 (CD/Fe@ZIF-67) as an activator. The 99.7% carbamazepine, 91.3% bisphenol A (BPA), and 95.4% diclofenac (DCF) degradation efficiency were achieved within 10 min, 60, and 1 min, respectively. The hydrophobicity of these three pollutants is positively correlated with their adsorption kinetic constants by CD/Fe@ZIF-67 due to the introduction of β-CD. Scavenger experiments and electron spin resonance spectra confirmed that carbamazepine was preferentially oxidized by SO4•- [λ(SO4•-)(70.5%) > λ(•OH)(28.2%) > λ(O2•-)(1.3%)], where SO4•- and O2•- played dominant roles in the degradation of BPA [λ(SO4•-)(71.7%) > λ(O2•-)(22.8%) > λ(•OH)(5.5%)], and O2•- was responsible for DCF removal [λ(O2•-) = 93.2%]. Additionally, the particulate catalyst was immobilized in the shell side of a ceramic membrane in a membrane reactor for catalyst recovery. This reactor achieved nearly 100% removal efficiency under optimal conditions: 0.036 wt % catalyst loading, 0.5 mM peroxymonosulfate concentration, 1 L inflow, 10 mg/L initial carbamazepine concentration, and 0.012 L/min hydraulic retention time. In summary, this study elucidates the active role of β-CD in a polymetallic/peroxymonosulfate system and provides valuable insights into the development of effective oxidation methods for pharmaceutical and personal care products in wastewater.

Bio-electrochemical degradation of carbamazepine (CBZ): A comprehensive study on effectiveness, degradation pathway, and toxicological assessment

Recent attention on the detrimental effects of pharmaceutically active compounds (PhACs) in natural water has spurred researchers to develop advanced wastewater treatment methods. Carbamazepine (CBZ), a widely recognized anticonvulsant, has often been a primary focus in numerous studies due to its prevalence and resistance to breaking down. This study aims to explore the effectiveness of a bio-electrochemical system in breaking down CBZ in polluted water and to assess the potential harmful effects of the treated wastewater. The results revealed bio-electro degradation process demonstrated a collaborative effect, achieving the highest CBZ degradation compared to electrodegradation and biodegradation techniques. Notably, a maximum CBZ degradation efficiency of 92.01% was attained using the bio-electrochemical system under specific conditions: Initial CBZ concentration of 60 mg/L, pH level at 7, 0.5% (v/v) inoculum dose, and an applied potential of 10 mV. The degradation pathway established by identifying intermediate products via High-Performance Liquid Chromatography-Mass Spectrometry, revealed the complete breakdown of CBZ without any toxic intermediates or end products. This finding was further validated through in vitro and in vivo toxicity assays, confirming the absence of harmful remnants after the degradation process.

Preparation of Cobalt-Nitrogen Co-Doped Carbon Nanotubes for Activated Peroxymonosulfate Degradation of Carbamazepine.

Cobalt-nitrogen co-doped carbon nanotubes (Co3@NCNT-800) were synthesized via a facile and economical approach to investigate the efficient degradation of organic pollutants in aqueous environments. This material demonstrated high catalytic efficiency in the degradation of carbamazepine (CBZ) in the presence of peroxymonosulfate (PMS). The experimental data revealed that at a neutral pH of 7 and an initial CBZ concentration of 20 mg/L, the application of Co3@NCNT-800 at 0.2 g/L facilitated a degradation rate of 64.7% within 60 min. Mechanistic investigations indicated that the presence of pyridinic nitrogen and cobalt species enhanced the generation of reactive oxygen species. Radical scavenging assays and electron spin resonance spectroscopy confirmed that radical and nonradical pathways contributed to CBZ degradation, with the nonradical mechanism being predominant. This research presents the development of a novel PMS catalyst, synthesized through an efficient and stable method, which provides a cost-effective solution for the remediation of organic contaminants in water.

Plant-based synthesis of TiO2 – rGO nanocomposite for the efficient photocatalytic degradation of an emerging contaminant: Experimental and theoretical investigations

The need to develop sustainable and efficient photocatalysts for the degradation of contaminants of emerging concern has gained considerable attention. In this study, plant-based titanium dioxide-reduced graphene oxide (TiO2-rGO) photocatalyst was synthesized by a hydrothermal method using Azadirachta indica (AI) leaf extract. Morphological and chemical properties of the AI-TiO2-rGO photocatalyst were evaluated in detail. The clusters of AI-TiO2 wrapped in AI-rGO were identified with TEM analysis, and from the XRD, the purity of AI-TiO2-rGO was confirmed. The low band gap (2.80 eV) of AI-TiO2-rGO made it a suitable photocatalyst under visible light. The X-ray photoelectron spectroscopy (XPS) results indicated the establishment of strong Ti-O-C chemical linkage within the AI-TiO2-rGO photocatalyst. The efficiency of AI-TiO2-rGO was assessed for the degradation of carbamazepine (CBZ) under UV-A irradiation (94.28%) and visible light (59.97%) in a batch photocatalytic reactor for 60 min. The optimized conditions such as AI-TiO2-rGO dosage (50 mg/L), initial CBZ concentration (4.5 mg/L), and light source (UV-A (60 W)), were validated with response surface methodology (RSM). The mechanism of degradation of CBZ by AI-TiO2-rGO was explained with the identification of intermediate compounds, and three plausible CBZ degradation pathways were proposed. The reusability study suggested that the AI-TiO2-rGO photocatalyst could be effectively used for 8 cycles. The evaluation of toxicity of treated water with E.Coli growth curve (reduction in Iind to 30.12% (UV) and 27.65% (visible)) signified that the treated water was less toxic. The comparison of AI-TiO2-rGO with chemically synthesized TiO2-rGO indicated that even though AI-TiO2-rGO exhibited a slightly higher band gap (2.80 eV), it can be the better alternative for the photocatalysts synthesized by chemical route. The economic analysis of the overall process proved that the application of AI-TiO2-rGO was more cost-effective and sustainable than the conventional TiO2 photocatalyst. Overall, the study provides valuable insight into synthesizing recyclable plant-based photocatalysts to degrade recalcitrant emerging contaminants in the water.

Removal efficiency and energy consumption optimisation for carbamazepine degradation in wastewater by electrohydraulic discharge.

The treatment of recalcitrant emerging pollutants is a major concern in wastewater treatment. The purpose of this study was the optimisation of emerging recalcitrant pollutant degradation using carbamazepine as a representative pollutant. Investigations of the carbamazepine degradation in wastewater was carried out by manipulating discharge current, air flow rate, and initial concentration to maximise removal efficiency and minimise energy consumption. The study utilised a three factor at two levels factorial design with randomised central runs. Discharge current, air flow rate, and initial concentration were the independent variables while to removal efficiency and minimise energy consumption were the response variables. ANOVA analysis was performed on the data. Discharge current, air flow rate, and initial concentration significantly impacted the removal efficiency to different degrees. However, for energy consumption, only current and air flow rate were the significant variables. The highest removal efficiency obtained was 93% ± 4% for 10 and 40 mg/L initial carbamazepine concentration after 10 minutes of plasma treatment at a current of 0.45 A and no air flow rate. The reactor demonstrated the capability to treat high cyclic organic chemical contaminant concentration in wastewater with possible applications in pre-concentrated wastewater remediation. However, there is still room for reactor design optimisation. One key area of focus is reducing treatment cost, which may be achieved theoretically, pending further experimental investigation, by introducing an alternating current power supply which can reduce energy consumption by 50-60%.

Alkyl chain length of quaternized SBA-15 and solution conditions determine hydrophobic and electrostatic interactions for carbamazepine adsorption

Santa Barbara Amorphous-15 (SBA) is a stable and mesoporous silica material. Quaternized SBA-15 with alkyl chains (QSBA) exhibits electrostatic attraction for anionic molecules via the N+ moiety of the ammonium group, whereas its alkyl chain length determines its hydrophobic interactions. In this study, QSBA with different alkyl chain lengths were synthesized using the trimethyl, dimethyloctyl, and dimethyoctadecyl groups (C1QSBA, C8QSBA, and C18QSBA, respectively). Carbamazepine (CBZ) is a widely prescribed pharmaceutical compound, but is difficult to remove using conventional water treatments. The CBZ adsorption characteristics of QSBA were examined to determine its adsorption mechanism by changing the alkyl chain length and solution conditions (pH and ionic strength). A longer alkyl chain resulted in slower adsorption (up to 120 min), while the amount of CBZ adsorbed was higher for longer alkyl chains per unit mass of QSBA at equilibrium. The maximum adsorption capacities of C1QSBA, C8QSBA, and C18QSBA, were 3.14, 6.56, and 24.5 mg/g, respectively, as obtained using the Langmuir model. For the tested initial CBZ concentrations (2–100 mg/L), the adsorption capacity increased with increasing alkyl chain length. Because CBZ does not dissociate readily (pKa = 13.9), stable hydrophobic adsorption was observed despite the changes in pH (0.41–0.92, 1.70–2.24, and 7.56–9.10 mg/g for C1QSBA, C8QSBA, and C18QSBA, respectively); the exception was pH 2. Increasing the ionic strength from 0.1 to 100 mM enhanced the adsorption capacity of C18QSBA from 9.27 ± 0.42 to 14.94 ± 0.17 mg/g because the hydrophobic interactions were increased while the electrostatic attraction of the N+ was reduced. Thus, the ionic strength was a stronger control factor determining hydrophobic adsorption of CBZ than the solution pH. Based on the changes in hydrophobicity, which depends on the alkyl chain length, it was possible to enhance CBZ adsorption and investigate the adsorption mechanism in detail. Thus, this study aids the development of adsorbents suitable for pharmaceuticals with controlling molecular structure of QSBA and solution conditions.

Removal of carbamazepine from water using mixed matrix membranes (MMMs) based on polyethersulfone and mesomaterials

The presence of recalcitrant compounds in aquatic systems, such as carbamazepine (CBZ), has intensified due to the wastewater discharge increase. This study aimed to evaluate the PES/mesoparticles-based MMM transport properties and their CBZ adsorption capacities in aqueous solutions with different physicochemical characteristics using a statistical design method. MMMs were synthesized via the phase inversion method using polyethersulfone as a polymeric matrix and mesoparticles as filler materials (MCM-41, NH2-MCM-41, or SH-MCM-41). The MMMs were characterized by ATR-FTIR, DSC, SEM-EDS, TGA, and XRD. CBZ quantification was performed by ultra-performance liquid chromatography. The preliminary adsorption study showed that PES/SH-MCM-41-based MMMs present the highest potential for CBZ adsorption. The multivariate design results indicate that three independent variables (contact time, initial CBZ concentration, and the amount of SH-MCM-41 incorporated in MMM) significantly influence the MMM adsorption capacity, while pH does not affect it. Water permeability tests in MMMs showed a correlation between the H2O permeability and the porosity of the synthesized membranes. PES/SH-MCM-41-based MMM showed high porosity and good ability to remove CBZ from water, regardless of the pH of the aqueous solutions.

Removal of Carbamazepine in Aqueous Solution by CoS2/Fe2+/PMS Process.

Carbamazepine (CBZ), as a typical pharmaceutical and personal care product (PPCP), cannot be efficiently removed by the conventional drinking water and wastewater treatment process. In this work, the CoS2/Fe2+/PMS process was applied for efficient elimination of CBZ. The CBZ removal efficiency of CoS2/Fe2+/PMS was 2.5 times and 23 times higher than that of CoS2/PMS and Fe2+/PMS, respectively. The intensity of DMPO-HO• and DMPO- followed the order of Fe2+/PMS < CoS2/PMS < CoS2/Fe2+/PMS, also suggesting the CoS2/Fe2+/PMS process has the highest oxidation activity. The effects of reaction conditions (e.g., CoS2 dosage, Fe2+ concentration, PMS concentration, initial CBZ concentration, pH, temperature) and water quality parameters (e.g., , , , , , humic acid) on the degradation of CBZ were also studied. Response surface methodology analysis was carried out to obtain the best conditions for the removal of CBZ, which are: Fe2+ = 70 µmol/L, PMS = 240 µmol/L, CoS2 = 0.59 g/L. The sustainability test demonstrated that the repeated use of CoS2 for 8 successive cycles resulted in little function decrease (<10%). These findings suggest that CoS2/Fe2+/PMS may be a promising method for advanced treatment of tailwater from sewage treatment plant.

G-C3N4/TiO2 S-scheme heterojunction photocatalyst with enhanced photocatalytic Carbamazepine degradation and mineralization

In the present work, UVA light-driven g-C3N4/TiO2 photocatalyst was synthesized for the photodegradation of Carbamazepine (CBZ) in aqueous medium. The morphological, the optical properties and the structure of the TiO2, g-C3N4 and the prepared composites were analyzed using X-ray diffraction (XRD), Nitrogen adsorption–desorption isotherm based on BET, Raman Spectroscopy, Scanning Electron Microscopy (SEM) with EDX, UV–vis Diffuse Reflectance Spectroscopy (UV–vis DRS). Optical absorption studies revealed a 2.97 and 2.78 eV of band gap for the developed composites for 10%g-C3N4/TiO2 (A10) and 30%g-C3N4/TiO2 (A30), respectively. The N2 adsorption–desorption isotherm showed an 80.64 and 59.67 m2/g of specific surface area for A10 and A30, respectively. Photodegradation studies show that A10 a composite photo-catalyst can eliminate 71.41% of CBZ with 30.38 % of mineralization yield within 360 min of UVA irradiation at optimum conditions (10 ppm of initial CBZ concentration and 0.1 g of 10%g-C3N4/TiO2 loading). The kinetic results showed that the removal of this pollutant nearly followed a First-order kinetic model with a regression coefficient (R2) values more than 0.98 and a high reaction rate constant recorded of 0.0034 min−1 for A10.

Carbamazepine removal from aqueous solution by synthesized reduced graphene oxide-nano zero valent iron (Fe0-rGO) composite: theory, process optimization, and coexisting drugs effects.

Synthesized Fe0-rGO nanocomposite with ratio of 1/1 (w/w) was prepared and has been used as adsorbent for the removal of Carbamazepine (CBZ) from aqueous solution. The adsorbent was characterized by various techniques such as Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Field Emission Scanning Electron Microscopy (FE-SEM) analyses. Linear experiments were performed to compare the best fitting isotherms and kinetics. The Freundlich isotherm (R2>0.90) and pseudo second order kinetic (R2>0.99) fitted well the experimental data. On the basis of the Langmuir isotherm, the maximum adsorption capacity of Fe0-rGO for CBZ was up to 50 mg g-1 at 30 °C. The pH, adsorbent dose, and initial concentration of CBZ were observed to be the leading parameters that affected the removal of CBZ considering the analysis of variance (ANOVA; p<0.05). The optimum process value of variables obtained by numerical optimization corresponds to pH 3.07, an adsorbent dose of 36.2 mg, an initial CBZ concentration of 5 mg L-1 and at 30.15 °C. The results of optimum conditions reveal that a maximum of 94% removal efficiency can be achieved; whereas, this phenomenon was independent of temperature (p-value>0.05). Moreover, Fe0-rGO can be used to remove diclofenac (DIC) and cetirizine (CTZ) simultaneously. To sum up, the Fe0-rGO is a promising adsorbent not only for the efficient removal of CBZ but also for the reduction of coexisting drugs in aqueous solution.

The synergistic interactions of reaction parameters in heterogeneous peroxymonosulfate oxidation: Reaction kinetic and catalytic mechanism

The reaction parameters including catalyst dosage, oxidant amount, initial contaminant concentration and pH etc. play the crucial roles in the heterogeneous persulfate oxidation processes, while the synergistic interactions among these reaction parameters are still obscure. We herein took an efficient heterogeneous persulfate oxidation system “bimetallic MnxCo3−xO4 solid solution (MnCo) activated peroxymonosulfate (PMS)” for carbamazepine (CBZ) removal from water. MnCo/PMS system exhibited outstanding performance that CBZ was completely removed within 10 min. The CBZ degradation performance was ascribed to the radical oxidation of SO4·- and O2·-, the nonradical oxidation of 1O2, the redox cycles between Mn and Co species and synergistic interactions among MnCo, PMS and CBZ. By monotonously or synchronously adjusting the MnCo dosage, PMS amount and initial CBZ concentration, the inherent connections of different reaction parameters were established. Strong and different synergistic interactions between MnCo and PMS, and among MnCo, PMS and CBZ, were existed due to the formation of three different reaction modes when reaction parameters met certain conditions. The features of the modes were “two-stage, the following auto-deceleration”, “one-stage, constant velocity” and “two-stage, the following auto-acceleration”. This discovery may provide new insights into the synergistic interactions of reaction parameters in advanced oxidation processes for wastewater treatment.

Degradation of carbamazepine by UVA/WO3/hypochlorite process: Kinetic modelling, water matrix effects, and density functional theory calculations

The rapid recombination of electron/hole pairs is a major setback in the application of WO3-based photocatalysis in water treatment. In this study, hypochlorite (ClO−) was used as an electron acceptor to enhance the photocatalytic degradation of carbamazepine (CBZ) using UVA-excited WO3. The results showed that CBZ degradation in the UVA/WO3/ClO− system followed a pseudo-first order reaction kinetic model. The addition of 0.1 mM ClO− to the UVA/WO3 system at pH values of 8.2 and 6.2 increased the rate constant (kobs) of the degradation process 5.3- and 11.5-fold, respectively. Further, increasing the WO3 dosage or decreasing the initial CBZ concentration resulted in an increase in kobs. However, at high concentrations, ClO− inhibited CBZ degradation. Based on the kinetic model, it could be suggested that ClO played a dominant role in the degradation process. Furthermore, the water matrix effects were as follows: the optimal pH was 6.2; humic acid, chloride, bicarbonate, and ammonium exhibited inhibitory effects on CBZ degradation; and sulfate ion significantly enhanced the degradation. Density functional theory (DFT) calculations indicated a strong affinity between ClO− and the WO3 surface. Specifically, the electrical energy per order that was associated with the use of ClO− varied in the range of 0.100–1.617 kWh/m3. In summary, this study shows that ClO− is an excellent electron acceptor for excited WO3, while clarifying the CBZ degradation-enhancing effect of ClO− as well as the kinetic model and DFT calculations. These findings can be employed in the degradation of recalcitrant contaminants in a cost-effective manner, while being significant for the development of more effective catalysts of UV-assisted advanced oxidation processes.

Mechanistic analysis of carbamazepine degradation in hybrid advanced oxidation process of hydrodynamic cavitation/UV/persulfate in the presence of ZnO/ZnFe2O4

The present study has addressed carbamazepine (CBZ) degradation by hybrid advanced oxidation system of hydrodynamic cavitation (HC) assisted UV/persulfate with composite ZnO/ZnFe2O4 particles. This hybrid system is comprised of several parallel pathways for generation of both OH and SO4∙- radicals. 98.13 ± 1.03% CBZ degradation was obtained at optimum operational conditions: inlet pressure = 9 atm, pH = 4, initial concentration of CBZ = 15 mg/L, UV power = 18 W, Na2S2O8 = 500 mg/L, ZnO/ZnFe2O4 = 500 mg/L. HC alone resulted in 7.70% degradation of CBZ, while the binary HC + Na2S2O8 system resulted in markedly high degradation of 65.73%. Composite ZnO/ZnFe2O4 particles had dual characteristics, viz. photocatalytic activity and a source of Fe2+/Fe3+ ions released through surface leaching. Relative contributions of OH and SO4∙- radicals to CBZ degradation were identified through permutation-combination of different oxidation systems. Thermodynamic and kinetic behaviors of reactions of CBZ with OH and SO4∙- radicals were analyzed using density functional theory (DFT) at B3LYP/6-31 g(d) level. Single electron transfer (SET) between CBZ and SO4∙- was the primary (and thermodynamically favorable) reaction pathway in initiation of degradation. Degradation intermediates revealed ionization of CBZ through SET before hydroxylation and oxidation – which was corroboration of DFT simulations.

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.

Efficient photocatalytic destruction of recalcitrant micropollutants using graphitic carbon nitride under simulated sunlight irradiation

The ubiquity of micropollutants (MPs) in aquatic environments has attracted increasing concern for public health and ecological security. Compared to conventional biological treatment, photocatalytic processes show more efficiency in degrading MPs, but they require expensive materials and complicated synthesis processes. This study developed an economic photocatalytic process to degrade micropollutants. We synthesized urea-based graphitic carbon nitride (g-C3N4) by a facile one-step pyrolysis method and evaluated the photocatalytic efficiency of carbamazepine (CBZ). Under simulated solar irradiation, g-C3N4 could achieve 100% removal efficiency of 0.1 mg/L CBZ in spiked wastewater effluent within 15 min, and 86.5% removal efficiency in wastewater influent after 20 min of irradiation. The porous structure of g-C3N4 promoted effective charge separation and mass transport of CBZ near the catalyst surface, enabling a high kinetic rate (0.3662 min −1). Reactive oxygen species trapping experiments revealed that superoxide radicals (O2•-) and holes (h+) were the major active radicals. Electron paramagnetic resonance (EPR) further confirmed the presence of O2•-, • OH, 1O2 and holes. The pH, light intensity and initial CBZ concentration were found to have significant impacts on the removal efficiency of CBZ. Possible reaction intermediates were identified and the degradation pathway was proposed. Multiple MPs were selected to further demonstrate photocatalytic efficiency of g-C3N4. The facile synthesis, superior efficiency, and versatility of g-C3N4 make it a promising catalyst for application in tertiary wastewater treatment processes.

Adsorption and removal of a selected emerging contaminant, carbamazepine, using Humic acid, Humasorb and Montmorillonite. Equilibrium isotherms, kinetics and effect of the water matrix

Carbamazepine is an antiepileptic drug that is not easily degraded in the environment. In this study, the removal of carbamazepine, an emerging contaminant, dissolved in deionized water and wastewater matrices by means of their adsorption onto Humic Acid, Humasorb and Montmorillonite was investigated. The effect of various parameters including adsorption time, adsorbent dosage, and initial adsorbate concentration was determined. The optimum exposure time for the removal of carbamazepine by Humic Acid was 30 min and by Humasorb and Montmorillonite were 2 h, in both distilled and wastewater. The maximum percent removal of carbamazepine by Humic Acid, Humasorb and Montmorillonite in deionized water was 90.5 ± 3.1%, 85.2 ± 2.3% and 83.8 ± 4.5% and in wastewater was 87.0 ± 1.5%, 87.3 ± 5.1% and 78.2 ± 1.2%, respectively, when the initial concentration of carbamazepine was 20 µg/mL and the mass of absorbent 100 mg in 10 mL samples. Three isotherms models including Langmuir, Freundlich, and Elovich were applied to the experimental data. It was found that the adsorption isotherms for the two adsorbents best matched Langmuir model indicating surface adsorption from deionized water (R2= 0.986 for Humic Acid, R2 = 0.955 for Humasorb and R2 = 0.865 for Montmorillonite) as well as from wastewater (R2 = 0.893 for Humic Acid, R2 = 0.949 for Humasorb and R2 = 0.984 for Montmorillonite). According to the kinetic studies, the pseudo-second-order kinetic model better fits to the removal of carbamazepine by the three adsorbents from both water matrices. However, pseudo-second-order model cannot exclusively explain the experimental data trend, but it could be explained by diffusion.

Carbamazepine biodegradation and volatile fatty acids production by selectively enriched sulfate‐reducing bacteria and fermentative acidogenic bacteria

AbstractBACKGROUNDThe micropollutant carbamazepine (CBZ) is persistent and resistant to conventional wastewater treatment. This study investigated the role of fermentative acidogenic bacteria (FAB) and sulfate‐reducing bacteria (SRB) for CBZ biodegradation and volatile fatty acid (VFA) production.RESULTSThe experimental results demonstrated that CBZ biodegradation, total organic carbon and sulfate removal efficiency reached 46%, 36% and 98%, respectively, after 144 h of operation with VFA production of acetic acid (20.72 mmol L−1), propionic acid (3.67 mmol L−1) and butyric acid (4.90 mmol L−1). However, the acetate fraction decreased from 78% to 70% with a decrease in chemical oxygen demand/sulfate (COD:SO42−) ratios from 1.06 to 0.35, respectively, suggesting that acetate was partially oxidized by SRB under substrate/COD limiting conditions. The biodegradation performance of SRB + FAB was also compared with that of a mixed microbial community (MMC).CONCLUSIONSUpon increasing the initial CBZ concentration from 42.3 to 169.2 μmol L−1, SRB + FAB exhibited much higher CBZ biodegradation (33%) than MMC (12%). Microbial community analyses confirmed the enrichment of VFA‐producing species including phylum Firmicutes (2.4% to 36.8%) and class Clostridia (1.3% to 29.6%). Moreover, aromatic and nitroaromatic compound‐degrading bacteria such as Escherichia and Desulfovibrio were also enriched. This signifies the applicability of SRB + FAB to pharmaceutical pollutant biodegradation in the environment. © 2020 Society of Chemical Industry (SCI)

Enhanced degradation of carbamazepine in FeOCl based Photo-Fenton reaction

Carbamazepine (CBZ) is one of the contaminants of emerging concerns due to its broad distribution in water environments. The present study evaluated various photo-Fenton reactions to achieve enhanced CBZ removal using FeOCl as the photo-Fenton catalyst that exhibited high activity in ·OH generation at a wide range of pH. The effects of UV irradiation, H2O2 concentration, initial CBZ concentration and catalyst dosage on the CBZ degradation efficiency were evaluated with uncertainty analysis. The H2O2 concentration of 10 μM, a catalyst dosage of 0.2 g/L, and the initial concentration of CBZ of 100 μM led to the highest CBZ removal rate of 92 % under UV/H2O2/FeOCl system within 0.5 h The effects of common anions (i.e., CO32−, HCO3, SO42−, NO3- and Cl-) on the CBZ degradation were studied. Three possible degradation pathways and three major degradation by-products were analyzed by LC−ESI−MS, which would provide new insight into the degradation mechanisms of CBZ in photo-Fenton reactions.

Carbamazepine sorption characteristics onto bentonite clay: Box-Behnken process design

A comprehensive study has been hold as a function of ionic strength, pH, equilibrium (Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models), kinetic (pseudo-first order, pseudo-second order and intraparticular kinetic models) and thermodynamic for the removal of carbamazepine (CBZ) from its aqueous solutions onto bentonite. A statistical experimental design method (Box-Behnken) has been applied for the optimal adsorption conditions (0.089 g resin/10.31 mL solution under 144 rpm mixing speed of shaking bath) in order to achieve the maximum yield (≈80% removal). Partition coefficient (PC) was also employed for the evaluation of the bentonite clay's performance. The equilibrium time was determined as 15 min depending on the kinetic study, where the maximum adsorption capacity (2.3550 mg g-1) and PC (0.0684 mg g-1 μM-1) were achieved for an initial CBZ concentration of ≈30 mg L-1. Effects of pH (3, 5, 7, 9 and 11) and ions (chloride, fluoride and lead) on the CBZ adsorption have been explored. The acidic media (pH ~ 3) enhanced the removal, while ionic strength caused to drop the adsorption from 22 to 51% depending on the ion and its concentration (0.17, 0.86 and 1.71 mol L-1 for chloride; 0.24, 0.48 and 0.95 mol L-1 for floride; 0.03, 0.15 and 0.30 mol L-1 for lead) in the solution. Finally, the nature of the adsorption process for the CBZ removal onto bentonite has been detected to be a non-spontaneous and endothermic, having a tendency to an irregular structure.

Removal of aqueous carbamazepine using graphene oxide nanoplatelets: process modelling and optimization

Unplanned and unmonitored developmental activities have resulted in a rapid emergence of pollutants like pharmaceuticals and personal care products (PPCPs) in the environment. These PPCPs are considered as potential health hazards. A wide variety of physical, biological and chemical processes are presently being investigated for ensuring the efficient removal of such pollutants from effluents. The present study investigates the potential of graphene oxide nanoplatelets (GONPs) for removal of a common and extensively used drug, Carbamazepine (CBZ) from aqueous solutions. Batch studies were performed to assess the potential of graphene oxide for adsorption of CBZ under different conditions of initial CBZ concentration, adsorbent dosage, temperature and solution pH. Process optimization was performed using Response Surface Methodology and Artificial Neural Network modelling. Results obtained indicated 99% CBZ removal under optimum solution pH, adsorbent dosage and treatment duration of 6, 1 g L− 1 and 120 min respectively. Results revealed that CBZ adsorption by GONPs followed Temkin isotherm and pseudo second order kinetics. A subsequent reusability study established that the GONPs could be reused for up to 8 times without any loss of adsorption efficiency. Therefore, it can be concluded that graphene oxide reported herein has immense potential for adsorption of trace organic pollutants from aqueous phases.