Removal Of Carbamazepine Research Articles

Removal of emerging pollutants from water using enzyme-immobilized activated carbon from coconut shell

This work reports the removal of diclofenac, amoxicillin, carbamazepine, and ciprofloxacin by utilizing three commercially available granular activated carbons (GACs) (Activated carbon, Silcarbon, and Donau) loaded with laccase. Adsorption was used to successfully immobilize laccase on the GACs, as revealed by scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX) and Fourier transform infrared spectroscopy (FTIR). In the three types of GACs tested, pH 5, 30 °C, and 2 mg mL−1 laccase content were found to be the optimum immobilization parameters. Laccase immobilization yields of 65.2%, 63.1%, and 62.9% were achieved with activated carbon, Silcarbon, and Donau respectively. The adsorption behaviors of the pharmaceuticals onto the tested activated carbons are best described as a spontaneous endothermic process that follows Langmuir isotherm and first-order kinetics. The reusability of the immobilized enzyme was evaluated using 2, 2′-azino-bis 3-ethylbenzothiazole-6-sulphonic acid (ABTS) as a substrate within six cycles for all adsorbents. In 120 mins, nearly a complete removal of the pharmaceutical compounds (50 mg L−1) was obtained in the case of activated carbon type and more than 90% for other adsorbent types when synergistic adsorption and enzymatic degradation were applied. With adsorption alone, 74% removal was obtained with activated carbon and < 56% for other adsorbents. The finding of this study suggests that biochar produced from coconut shell (same as the one used in this study) can effectively be used as a substrate and adsorbent for pharmaceutical removal. This enzymatic physical removal system has the potential to be applied on a large-scale.

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.

Template-free formation of BiOCl double-shelled hollow microspheres with enhanced carbamazepine removal efficiency

Constructing three-dimensional (3D) hierarchical structure is regarded as an effective strategy to alleviate the inherent drawbacks of the BiOCl bulk structure and realize the optimization of photocatalytic performance. Herein, a unique BiOCl double-shelled hollow microsphere structure with adjustable shell thickness is fabricated through a template-free one-pot solvothermal method for the first time. A plausible formation mechanism is proposed by exploring the morphological changes during the growth process. The as-obtained hollow microspheres photocatalyst exhibits excellent carbamazepine (CBZ) degradation efficiency (97.5%) under simulated solar irradiation, the corresponding apparent rate constant is about 4 times and 3 times than that of conventional BiOCl solid microspheres. The experimental and characterization results show that the existence of nanosheet subunits and porous structures shorten the diffusion length of charge carriers, which is conducive to the separation and transfer of photogenerated. Meanwhile, the construction of double-shelled hollow structure achieves higher light utilization. This work demonstrates the superior performance of catalysts with hierarchical hollow structures for pollutant degradation and provides new ideas to further optimize the photocatalytic performance of BiOCl-based materials.

Oxidation of Pharmaceuticals by Ferrate(VI)-Amino Acid Systems: Enhancement by Proline.

The occurrence of micropollutants in water threatens public health and ecology. Removal of micropollutants such as pharmaceuticals by a green oxidant, ferrate(VI) (FeVIO42-, Fe(VI)) can be accomplished. However, electron-deficient pharmaceuticals, such as carbamazepine (CBZ) showed a low removal rate by Fe(VI). This work investigates the activation of Fe(VI) by adding nine amino acids (AA) of different functionalities to accelerate the removal of CBZ in water under mild alkaline conditions. Among the studied amino acids, proline, a cyclic AA, had the highest removal of CBZ. The accelerated effect of proline was ascribed by demonstrating the involvement of highly reactive intermediate Fe(V) species, generated by one-electron transfer by the reaction of Fe(VI) with proline (i.e., Fe(VI) + proline → Fe(V) + proline•). The degradation kinetics of CBZ by a Fe(VI)-proline system was interpreted by kinetic modeling of the reactions involved that estimated the rate of the reaction of Fe(V) with CBZ as (1.03 ± 0.21) × 106 M-1 s-1, which was several orders of magnitude greater than that of Fe(VI) of 2.25 M-1 s-1. Overall, natural compounds such as amino acids may be applied to increase the removal efficiency of recalcitrant micropollutants by Fe(VI).

Evolvement of carbamazepine under solar irradiation in the presence of chlorine: Efficiency, influences, degradation pathways and ecotoxicity

Carbamazepine (CBZ) and residual chlorine coexist in wastewater discharged from wastewater treatment plants (WWTPs), while the mechanism of their photochemical transformation in the natural aquatic environment is still unclear. In this study, an approach combining experiment and quantum chemical calculation was used to explore the degradation mechanism of CBZ under chlorine/solar irradiation. The degradation of CBZ was not evident during disinfection alone or sunlight irradiation. However, CBZ was rapidly degraded under chlorine/solar irradiation (kobs = 0.463 min−1 at pH = 8.0). Quenching and probe experiments showed that the efficient removal of CBZ under chlorine/solar irradiation was credited with the production of ·Cl, ·OH, and O3, in which ·Cl (61.95%) and ·OH (33.14%) contributed significantly. The reaction mechanism of CBZ degradation was postulated, in conjunction with the identification of degradation products by HPLC/MS analysis and density functional theory. Among them, the primary degradation way was acridine production under the action of ·Cl and ·OH, and the decarboxylation process was the rate-limiting step. In addition, bioassay results indicated that the luminescent bacteria toxicity and genotoxicity of CBZ after chlorine/solar irradiation increased. Based on the identified transformation products and the quantitative structure-activity relationship, the elevated ecotoxicity was attributed to the TP209 and TP179 generated by pathway 1, and then controlling the decarboxylation process by adjusting pH and temperature to reduce the high toxic degradation products were proposed for ecological safety.

Passive Ozone Injection through Gas-Permeable Membranes for Advanced In Situ Groundwater Remediation

In this work, we examine an alternative ozone delivery method for groundwater remediation using permeable membranes. A cylindrical polydimethylsiloxane (PDMS) membrane was used for passive ozone injection in a two-dimensional system simulating in situ groundwater treatment. Liquid velocity and presence of ozone consumers (e.g., nitrite) were found to regulate the ozone diffusion rate through the membrane and the resultant dissolved ozone concentration. A higher liquid velocity (examined in a 340–920 cm day–1 range) resulted in an increase in ozone diffusion rates (up to 2 μmol s–1 m–2) and a decrease in dissolved ozone concentration due to a dilution effect. Similarly, increasing the nitrite concentration from 0.5 to 25 mM enhanced the ozone diffusion rate by up to 5.64 μmol s–1 m–2. To examine the membrane performance, carbamazepine was used as a fast-reacting model pollutant. Up to 80% carbamazepine removal was obtained for the lowest liquid velocity examined, which is also relevant for typical groundwater velocities. However, a low ratio of carbamazepine-removed to ozone-delivered was obtained, which was associated with reactions occurring close to the membrane surface that may enable additional reactions of ozone with carbamazepine transformation products. Overall, this study provides new insights to support planning and design of groundwater applications using permeable membranes in reactive permeable barrier mode.

Adsorption of Carbamazepine in All-Silica Zeolites Studied with Density Functional Theory Calculations.

The anticonvulsant drug carbamazepine (-) is an emerging contaminant of considerable concern due to its hazard potential and environmental persistence. Previous experimental studies proposed hydrophobic zeolites as promising adsorbents for the removal of carbamazepine from water, but only a few framework types were considered in those investigations. In the present work, electronic structure calculations based on dispersion-corrected density functional theory (DFT) were used to study the adsorption of CBZ in eleven all-silica zeolites having different pore sizes and connectivities of the pore system (AFI, ATS, BEA, CFI, DON, FAU, IFR, ISV, MOR, SFH, SSF framework types). It was found that some zeolites with one-dimensional channels formed by twelve-membered rings (IFR, AFI) exhibit the highest affinity towards CBZ. A "good fit" of CBZ into the zeolite pores that maximizes dispersion interactions was identified as the dominant factor determining the interaction strength. Further calculations addressed the role of temperature (for selected systems) and of guest-guest interactions between coadsorbed CBZ molecules. In addition to predicting zeolite frameworks of particular interest as materials for selective CBZ removal, the calculations presented here also contribute to the atomic-level understanding of the interaction of functional organic molecules with all-silica zeolites.

Prediction of pharmaceuticals removal in activated sludge system under different operational parameters using an extended ASM-PhACs model

Removal of pharmaceuticals is essential in wastewater treatment systems due to their release and accumulation in the environment, which are raising issues for the environment and human health. A mathematical model could be used to predict pharmaceuticals removal under various operational parameters and assess the contributions of different removal pathways to pharmaceuticals removal. Here an ASM-PhACs model was established to describe pharmaceuticals removal including diclofenac (DCF), erythromycin (ERY), gemfibrozil (GEM) and carbamazepine (CBZ) removal in activated sludge system. The pharmaceuticals removal processes linked to co-metabolic biodegradation through the growth of ammonia oxidizing bacteria (AOB), metabolic biodegradation through AOB, metabolic biodegradation through heterotrophic bacteria (HB) and sludge adsorption were incorporated into activated sludge model (ASM1) framework. The kinetic equations were established for each pharmaceuticals removal process. To provide the experimental data for model calibration and validation, two sets of batch tests were designed and conducted in the laboratory scale using SBR technology. According to the batch test data and results of sensitivity analysis, the newly added parameters and some original default parameters affecting pharmaceuticals removal processes were screened and calibrated. The model could accurately simulate all the dynamics of chemical oxygen demand, nitrogen and pharmaceuticals under various conditions. To explore the effect of operational parameters on pharmaceuticals removal efficiency, the wide range of operational parameters was analyzed during model simulation. According to the simulation results, both influent NH4+-N concentration and DO were found to be the significant parameters that impact the removal of DCF, ERY and GEM. AOB biodegradation played an important role in DCF, ERY and GEM removal. The developed model framework helps to investigate the removal mechanisms and key influencing factors of pharmaceuticals removal, thus providing guidelines for reactor design, operation and optimization aiming at pharmaceuticals removal.

Ex-situ magnetic activated carbon for the adsorption of three pharmaceuticals with distinct physicochemical properties from real wastewater.

Pharmaceuticals are able to evade conventional wastewater treatments and therefore, are recurrently found in the environment with proven potential to cause harm to human and wildlife. Adsorption onto activated carbon (AC) is a promising complement. However, AC production from non-renewable resources and its difficult after-use recuperation are prohibitive. Hence, a waste-based magnetic activated carbon (MAC) was produced from paper mill sludge, via an ex-situ synthesis, for the adsorptive removal of carbamazepine (CBZ), sulfamethoxazole (SMX) and ibuprofen (IBU) from ultrapure water and wastewater. The MAC was obtained through the promotion of electrostatic interactions between magnetic and activated carbon particles in a water suspension at controlled pH between the points of zero charge of both surfaces. The optimized condition (MACX3) presented remarkable properties regarding specific surface area (SBET=795m2 g-1) and saturation magnetization (MS=19emug-1). Kinetic and equilibrium adsorption studies were performed under batch conditions. Adsorption equilibrium was reached in up to 30min for all pharmaceuticals in both matrices, proving the low dependence on the adsorbate and the broad applicability of MACX3 in pharmaceutical adsorption. Regarding equilibrium experiments, high Langmuir maximum adsorption capacities (qm) were achieved in ultrapure water (up to 711 ± 40 µmol g-1). Equilibrium studies in wastewater revealed a decay in qm when compared to ultrapure water: 28% for CBZ (468 ± 20 µmol g-1 (111 ± 5 mg g-1)), 78% for SMX (145±10 µmol g-1 (37 ± 3 mg g-1)) and 62% for IBU (273 ± 8 µmol g-1 (56 ± 2 mg g-1)), attributed to the wastewater pH, which dictates the speciation of the pharmaceuticals and controls electrostatic interactions between pharmaceuticals and MAC, and to competition effects by organic matter. It was demonstrated the promising applicability of a waste-based ex-situ MAC, rapidly retrievable from water, as an alternative tertiary wastewater treatment for pharmaceuticals removal.

Using integrative samplers to estimate the removal of pharmaceuticals and personal care products in a WWTP and by soil aquifer treatment enhanced with a reactive barrier

The need and availability of freshwater is a major environmental issue, aggravated by climate change. It is necessary to find alternative sources of freshwater. Wastewater could represent a valid option but requires extensive treatment to remove wastewater-borne contaminants, such as contaminants of emerging concern (CECs). It is urgent to develop not only sustainable and effective wastewater treatment techniques, but also water quality assessment methods. In this study, we used polar organic chemical integrative samplers (POCIS) to investigate the presence and abatement of contaminants in an urban wastewater treatment plant (WWTP) and in soil aquifer treatment (SAT) systems (a conventional one and one enhanced with a reactive barrier). This approach allowed us to overcome inter-day and intraday variability of the wastewater composition. Passive sampler extracts were analyzed to investigate contamination from 56 pharmaceuticals and personal care products (PPCPs). Data from the POCIS were used to estimate PPCPs' removal efficiency along the WWTP and the SAT systems. A total of 31 compounds, out of the 56 investigated, were detected in the WWTP influent. Removal rates along WWTP were highly variable (16-100 %), with benzophenone-3, benzophenone-1, parabens, ciprofloxacin, ibuprofen, and acetaminophen as the most effectively removed chemicals. The two SAT systems yielded much higher elimination rates than those achieved through the primary and secondary treatments together. The SAT system that integrated a reactive barrier, based on sustainable materials to promote enhanced elimination of CECs, was significantly more efficient than the conventional one. The removal of the recalcitrant carbamazepine and its epoxy- metabolite was especially remarkable in this SAT, with removal rates between 69–81 % and 63–70 %, respectively.

Removal of pharmaceutically active compounds (PhACs) by zero-valent iron: quantification of removal mechanisms consisting of degradation, adsorption and co-precipitation.

The removal mechanisms of carbamazepine (CBZ), which is one of pharmaceutically active compounds, using zero-valent iron (ZVI) were quantified by defining three fractions, namely "degradation", "adsorption", and "co-precipitation". The maximum total organic carbon (TOC) removal was obtained at pH 4. The results demonstrate that the adsorption on the ZVI surface is dominant in the TOC removal of CBZ for 4 ≤ pH ≤ 6 while the degradation by oxidative and reductive reactions is efficient exclusively for pH ≤ 3. TOC removal was not obtained for pH ≥ 8. The most dominant mechanism in the removal of CBZ by ZVI is the adsorption onto the iron oxides/hydroxides layer formed on ZVI surface rather than the degradation by oxidative and reductive reactions including Fenton and Fenton-like reactions for pH ≥ 4. A novel kinetic model for removal of CBZ by ZVI was developed to simulate the dynamic concentration profiles of CBZ, TOC, total Fe ions, and dissolved oxygen linked closely with each other and the contributions of degradation, adsorption, and co-precipitation in TOC removal of CBZ. Reasonable agreement between experimental data and model predictions suggests the applicability of the proposed kinetic model to quantitatively analyze the mechanisms of CBZ removal by ZVI.

Enhancement of carbamazepine removal rate using Tetradesmus obliquus KNUA061 and NaOCl and utilization of the resulting biomass

Pharmaceutical and personal care products (PPCPs) are discharged into receiving water bodies mainly from sewage treatment plants. Due to the inefficient removal in conventional wastewater treatment facilities, PPCPs have become a major concern to aquatic ecosystems, water quality, and public health worldwide since they cause harmful effects on aquatic life and human even at low doses. Among the PPCPs, carbamazepine (CBZ) is one of the most commonly prescribed anticonvulsant drugs and consumed more than 1,000 tons per year. Due to its structural complexity, CBZ is known as recalcitrant compound highly stable during wastewater treatment. Consequently, it has become one of the most frequently detected pharmaceuticals in waste water, surface water, and even drinking water. In this study, Korean indigenous microalgae strains were tested as eco-friendly and cost-effective solutions for CBZ removal. Based on the preliminary biological CBZ degradation tests, Tetradesmus obliquus KNUA061 demonstrating the best CBZ removal rate was selected for further experiments. In order to increase strain KNUA061's CBZ removal efficiency, NaOCl, which is widely accepted in the water purification process, was used as an additional stimulus to induce stress conditions. At around 20 μg L−1 CBZ, addition of 1.0 mg NaOCl resulted in approximately 20% of removal rate increase without suppressing cells growth. Roughly 90% of CBZ remained its original form and the composition of the transformed secondary metabolites was less than 10% during the biodegradation process by the microalga. Based on the results of the antioxidant enzyme activities, degree of lipid oxidation, and amino acid contents, it was concluded that the redox-defence system in microalgal cells may have been activated by the NaOCl treatment. Biomass analysis results showed that higher heating value (HHV) of strain KNUA061 biomass was higher than those of lignocellulosic energy crops suggesting that it could be utilized as a possible renewable energy source. Even though its biodiesel properties were slightly below the international standards due to the high PUFA contents, the biodiesel produced from T. obliquus KNUA061 could be used as a blending resource for transportation fuels. It was also determined that the microalgal biomass has acceptable feasibility as a sustainable dietary supplement feedstock due to its high essential amino acid contents.

An Electrode with Two‐Level Porosity for Electro‐Fenton: Carbon Nanofiber‐Functionalized Macroporous Nickel Foam

AbstractCarbon is an established electrode material in electrochemical reactors, e.g., for the generation of hydrogen peroxide (H2O2). Common structures are graphite felts or carbon fibers. These materials usually lack adequate electrochemical activity, hence more selectively active moieties need to be introduced. Furthermore, the commonly porous materials require immobilization concepts which normally include polymeric binders that partly block the porous surface and may entail secondary pollution. This work introduces carbon nanofibers (CNFs), synthesized on nickel foams via catalytic carbon decomposition, as a novel, binder‐free electrode with two‐level porosity. The fibers are in the range of few nanometers and comprise embedded nickel nanoparticles (30–250 nm). The CNFs are deposited as a thin layer on a nickel foam, not affecting its intrinsically open‐porous nature. The as‐synthesized CNF/Ni foams show H2O2 production rates as high as 1.1 mg h−1 cm−2 at pH 3 and a cathodic potential of 0.11 V versus reversible hydrogen electrode (RHE) through multiple reaction pathways catalyzed by CNF and embedded nickel nanoparticles. In an electro‐Fenton process, the removal of carbamazepine (CBZ), a frequently detected micropollutant in water bodies is assessed, demonstrating an almost complete depletion after 10 min (cCBZ,0 = 4 mg L−1). These results unveil the potential of the integrated production of CNF/Ni foam electrodes with scale‐up perspectives for oxygen reduction reactions.

UV and Zero-Valent Iron (ZVI) Activated Continuous Flow Persulfate Oxidation of Municipal Wastewater

Currently, sulfate-radical-based advanced oxidation processes are promising candidates to become viable post-treatment processes for wastewater purification. In this work, a continuous flow UV light/persulfate (PS)/zero-valent iron (ZVI) system has been applied for wastewater treatment for the first time. The influence of certain photo-Fenton-like process parameters, such as space time, PS concentration, and PS to ZVI molar ratio, on the removal of total organic carbon (TOC), was examined using the Box–Behnken design. First, synthetic municipal wastewater was used for the experiments, and the polynomial regression model was constructed utilizing the real data by using the response surface methodology (RSM). The adequacy of the RSM model was assessed by analysis of variance, which showed that the model was reliable and could be applied to improve the process parameters for TOC removal. Moreover, both synthetic and real municipal wastewater were spiked with carbamazepine (CBZ), which is commonly prescribed as an antiepileptic drug, to investigate its fate in the UV/PS/ZVI system. With a space time of 60 min, PS concentration of 60 mM, and PS to ZVI molar ratio of 15, it was possible to remove 71% of TOC and completely remove CBZ from the synthetic municipal wastewater, whereas a 60% TOC removal and complete removal of CBZ were achieved at a space time of 50 min, PS concentration of 50 mM, and PS/ZVI molar ratio of 15 for the real municipal wastewater. This difference in TOC removal could possibly be linked to the complex matrix of the real wastewater and the presence of radical scavenging agents.

Coupled adsorption and non-radical dominated mechanisms in Co, N-doped graphite via peroxymonosulfate activation for efficiently degradation of carbamazepine

A ZIF-derived Co, N-doped graphitic carbon prepared by calcination exhibited excellent carbamazepine (CBZ) removal ability over a broad pH range for peroxymonosulfate (PMS) activation. The impact of calcining temperature on catalyst constitution and catalytic behavior were studied through characterization and performance experiments. Benefiting from the synergy of adsorption and catalysis, CZIF-1000/PMS (with a 1000 °C pyrolysis temperature) system demonstrated outstanding catalytic capability, with 96.8 % removal efficiency supported by optimum parameters (catalyst dosage, 50 mg/L, PMS dosage, 0.4 mM, CBZ concentration, 5 ppm, and initial pH, 5.8). The graphitic N, pyrrolic N, CO group, Co3+ and Co0 were revealed to be the activation centers by X-ray photoelectron spectroscopy (XPS). Mechanisms exploration suggested that dual active pathways, including singlet oxygen-dominated non-radical pathway and sulfate radical-dominated radical pathway were involved in the reaction mechanism. Besides, a total of ten intermediates were detected and CBZ degradation pathways were derived subsequently.

Simultaneous Carbamazepine and Phosphate Removal from a Moving-Bed Membrane Bioreactor Effluent by the Electrochemical Process: Treatment Optimization by Factorial Design.

Pharmaceutical and personal care products are frequently used in various fields and released into water bodies from the outlets of wastewater treatment plants. These products can harm the environment and human health even at low concentrations. Carbamazepine (CBZ), the most persistent pharmaceutical, has frequently been found in surface waters that bypassed the secondary treatments of conventional activated sludge. In addition, the treatment of phosphate in wastewater by the electrochemical process has recently attracted much attention because of its ability to remove, recover, and prevent environmental problems associated with eutrophication. This study proposes using the electrochemical process as an advanced oxidation process to simultaneously treat CBZ and phosphate from the moving-bed membrane bioreactor effluent. The study includes a long-term survey of CBZ treatment efficiency and common parameters of synthetic wastewater in the moving-bed membrane bioreactor system. Afterward, the electrochemical process is applied as an advanced oxidation process for the simultaneous removal of CBZ and phosphate from the moving-bed membrane bioreactor. Under the investigated conditions, CBZ has proven not to be an inhibitor of microbial activity, as evidenced by the high extent of chemical oxygen demand and nutrient removal. Using a factorial design, the electrochemical process using Pt/Ti as anode and cathode under optimal conditions (reaction time-80 min, bias potential-3 V, and electrode distance-1 cm) resulted in as high as 56.94% CBZ and 95.95% phosphate removal, respectively. The results demonstrated the ability to combine an electrochemical and a moving-bed membrane bioreactor process to simultaneously remove CBZ and phosphate in wastewater.

Grape-like CNTs/BaTiO3 nanocatalyst boosted hydraulic-driven piezo-activation of peroxymonosulfate for carbamazepine removal

• Grape-like CNTs/BT nanocomposite catalyst with Ti − C bond was synthesized. • CNTs/BT boosted hydraulic-driven piezo-activation of PMS for CBZ removal. • CNTs/BT-PMS system generated much more ROS than BT-PMS and CNTs-PMS systems with less energy. • CNTs acted as fast electron lanes for accelerating separation of piezoelectric carriers. • Piezoelectric field effectively suppressed destruction of CNTs in PMS system. Both carbon nanotubes (CNTs) and piezoelectric materials can activate peroxymonosulfate (PMS). However, the activation of PMS by CNTs suffers from poor reusability while hydraulic-driven piezo-activation of PMS faces the problem of limited charge separation. To solve the above problems, grape-like CNTs/BaTiO 3 (CNTs/BT) nanocatalyst with a Ti − C bond was prepared. Results indicated that hydraulic-driven CNTs/BT-PMS system offered remarkable carbamazepine removal efficiency (91.93%, 120 min) with satisfactory reusability. The energy consumption of PMS activation by CNTs/BT was only 39.33% and 26.59% of those by CNTs and BT, respectively. Piezoresponse force microscopy and finite element simulation further suggested that these superior performances were mainly responsible for the synergistic effects of CNTs and BT, leading to stronger piezoelectric response with efficient piezo-generated charge separation, which in turn improved the efficiency for producing reactive species. Notably, the built-in piezoelectric field of BT constantly replenished electrons to CNTs and effectively suppressed the destruction of CNTs caused by chemical oxidation. This durable composite might be a promising catalyst for PMS activation with potential utilization of residual hydraulic power during water treatment.

Degradation of carbamazepine from wastewater by ultrasound-enhanced zero-valent iron -activated persulfate system (US/Fe0/PS): kinetics, intermediates and pathways

ABSTRACT Carbamazepine (CBZ) is a common antiepileptic drug. CBZ enters the environment through unreasonable and standardized ways such as human and animal metabolites, discarded drugs, and more than half of its metabolites are released into the environment. Since CBZ is not easy to be degraded, continuous input of CBZ into the water environment will cause long-term impact on the water ecological environment and seriously endanger human health. Aiming at how to degrade wastewater containing carbamazepine, studies were conducted on the degradation of carbamazepine by ultrasound/zero-valent iron/persulfate system (US/ F e 0 /PS). Firstly, the removal effects of carbamazepine by different systems, such as ultrasound/sodium persulfate (US/PS), zero-valent iron/persulfate system ( F e 0 /PS) and US/ F e 0 /PS, were compared; Secondly, the influence of factors, such as ultrasonic power, sodium persulfate dosage, zero-valent iron dosage, reaction temperature, pH, etc., on the reaction was investigated by the control variables method. Results show that ultrasound power, PS concentration, pH and temperature have a great influence on the removal of carbamazepine in US/Fe0/PS reaction system. Besides, the optimum parameters for degradation of carbamazepine with US/ F e 0 /PS reaction system were determined ([CBZ]0 = 0.025 mM; [PS]0 = 0.4 mM; Fe0 = 4.0 mg/L; ultrasonic power = 40 W; T = 30 ℃; initial pH = 5.0). Finally, the intermediates and degradation pathways of carbamazepine by US/ F e 0 /PS system were analyzed and speculated. It was inferred that two intermediates were generated during the degradation of carbamazepine, mainly through the ring opening and decyclization of piperazine rings. It was proved that process US/ F e 0 /PS has a very important application value in the degradation of antibiotic-containing wastewater.

Synthesis of nitrogen doped and nitrogen and sulfur co-doped carbon cryogels and their application for pharmaceuticals removal from water

In this study carbon cryogel, cryogel doped with nitrogen, and both nitrogen and sulfur co-doped carbon cryogels (nominal concentration of nitrogen was in the range 2–10 wt%) were synthesized and used as an adsorbent for the removal of carbamazepine, naproxen, diazepam and diclofenac from water. A batch adsorption kinetics study was performed by determination of contact time influence, the effect of pH, and adsorption isotherms. Structural and morphological analysis showed that there are no changes in turbostratic carbon structure induced by doping/co-doping, but noticeable morphology changes were observed. The presence of both nitrogen and nitrogen/sulfur were confirmed and results showed low content on the surface, especially for sulfur. Obtained high values of the specific surface area for co-doped samples (up to 1530 m2/g) can be caused by sulfur atoms burning or leaving the material during carbonization. The results of the adsorption kinetics study showed that the adsorption of all pharmaceuticals on all tested samples followed the pseudo-second-order kinetic model. The maximum adsorption capacity obtained from the Langmuir isotherm model is higher for doped (91.28–168.92 mg/g) and co-doped (152.97–488.06 mg/g) samples than for pristine sample (59.75–266.28 mg/g). Calculated adsorption energy values from the Dubinin-Radushkevich model indicate that the possible mechanism was physisorption. Desorption tests that were carried out showed satisfactory reusability for all samples. The favorable adsorption characteristics for the co-doped sample with a higher nominal concentration of nitrogen and sulfur qualifies as a potentially good adsorbent for the removal of pharmaceuticals from water.

Eggshell supported Cu doped FeOx magnetic nanoparticles as peroxymonosulfate activator for carbamazepine degradation

In this study, a composite of eggshell supported Cu doped FeOx nanoparticles(FeCuOx/eggshell) was synthesized using a facile co-precipitation method, morphologies and properties were systematically characterized. Meanwhile, catalytic performance of the FeCuOx/eggshell & peroxymonosulfate (PMS) system for carbamazepine (CBZ) degradation, effect of operation parameters and water matrices on CBZ removal in this system were evaluated. Besides, Reactive Oxygen Species (ROSs) responsible for the oxidation of CBZ were identified through series of experiments, and a possible degradation pathway of CBZ was proposed. Furthermore, possible reaction mechanism, possible decomposition pathways were proposed. Evolution of CBZ solution toxicity was also evaluated. In addition, installation of FeCuOx/eggshell into PAN membrane has been proved to improve stability and reduce metal release.