Carbamazepine Removal Efficiency Research Articles

Removal of carbamazepine from aqueous solution using sono-activated persulfate process

This study investigated systematically the removal of carbamazepine (CBZ) in solution using the combination of ultrasound and persulfate anions to identify the factors affecting the kinetics of the process. The effects of reaction time, initial persulfate anion concentration, initial CBZ concentration, ultrasonic power input, solution pH and temperature on CBZ removal efficiency were examined. The sulfate radical oxidation of CBZ in the presence of ultrasonic irradiation showed a significant synergistic effect on CBZ removal. It is found that up to 89.4% CBZ removal efficiency was achieved after 120min reaction. The removal process of CBZ in solution could be described using pseudo-first-order kinetics. In this system, sulfate radicals (SO4−) were considered to be the mainly oxidant to remove CBZ while ultrasound power input could affect CBZ removal efficiency significantly. Changing solution pH influenced the CBZ removal efficiency and the best performance would be achieved at pH 5.0.

REMOVAL OF CARBAMAZEPINE BY ELECTROCOAGULATION: INVESTIGATION OF SOME KEY OPERATIONAL PARAMETERS

The performance of electrocoagulation (EC) process, a non-specific electrochemical technology, was investigated for the removal of carbamazepine (CBZ), an antiepileptic drug, from water. Experiments were carried out in synthetic wastewater in a batch cell. The respective influences of some key process parameters were studied, such as mixing conditions, initial pH, and current on aluminium electrodes. Experimental results showed that a CBZ removal efficiency of 62% was observed under slightly acidic initial conditions (pH 4) with a current density as high as 44 mA cm -2 (I=4.5 A) using Al electrode. This clearly indicates that CBZ removal proceeds through an electrochemical mechanism, while the adsorption of CBZ onto the aluminum hydroxide flocs was shown to be negligible. Furthermore, the increase of initial pH to alkaline values was shown to decrease the drug elimination efficiency. Conversely, as expected, an increase of current intensity improved the removal of CBZ. As a result, low initial pH 4 coupled with high current elevates the electrochemical elimination of CBZ: in this case, one metabolite could also be detected.

Sonoelectrochemical oxidation of carbamazepine in waters: optimization using response surface methodology

AbstractBACKGROUNDThe decomposition of carbamazepine (CBZ) in synthetic solution and in municipal effluent was investigated using a sono‐electrochemical reactor. Sono‐electrolysis was conducted using two concentrical electrodes installed in a cylindrical reactor containing a ceramic transducer.RESULTSCBZ concentration (C0=10 mg L−1) optimally diminished up to 90% by applying a current intensity of 4.86 A for 177 min and by imposing an ultrasound power of 38.29 W. The optimal conditions were subsequently applied for tertiary treatment of municipal wastewater effluent contaminated with 10 µg CBZ L−1. The reported removal efficiencies of CBZ, TOC, COD and colour were 93%, 60%, 93% and 86%, respectively. Likewise, the toxicity was completely removed (bacterium Vibrio fisheri) from the municipal wastewater effluent (>96%).CONCLUSIONSThe advantages of coupling ultrasonication and electrooxidation (US‐EO) treatment for CBZ removal were demonstrated. An experimental design methodology based on response surface methodology was applied to determine the optimal experimental conditions in terms of cost/effectiveness of removal. © 2014 Society of Chemical Industry

Degradation of carbamazepine by Fe(II)-activated persulfate process

Experimental studies were conducted to investigate the oxidative degradation of carbamazepine (CBZ), one of the most frequently detected pharmaceuticals in various waters, by Fe(II)-activated persulfate process. Results show that the Fe2+/S2O82− process is very effective for the elimination of CBZ and characterized by a two-stage kinetics (a rapid initial decay followed by a retardation stage). CBZ degradation reaction was observed to be pH dependent and the optimum pH is 3.0 in the range of 2.00–7.87. The concentration of Fe2+ and S2O82− exhibited a noticeable influence on CBZ removal efficiency, where [S2O82−] exerted more significant effects than that of [Fe2+]. The optimal molar ratio of CBZ, Fe2+, and S2O82− is found to be 1:5:40. The effect of various inorganic anions on CBZ removal was also evaluated under the optimal conditions. The anions NO3−, SO42− and H2PO4-caused a negative effect on the performance of this process, while Cl− interestingly accelerated CBZ degradation. The higher the Cl− concentration, the faster the CBZ decay rate. The intermediates were identified during CBZ degradation with and without the presence of Cl−. The evolution of intermediates for these two scenarios was compared. The decay pathways of CBZ were proposed accordingly.

Biosorption of clofibric acid and carbamazepine in aqueous solution by agricultural waste rice straw

Due to their widespread use, clofibric acid (CA) and carbamazepine (CBZ) have been frequently detected simultaneously at relatively high concentrations in aquatic environments. In this study, agricultural waste rice straw was employed as a potentially low-cost, effective and easy-to-operate biosorbent (RSB) to remove CA and CBZ. The adsorption of both pharmaceuticals followed pseudo second-order kinetics, and intraparticle diffusion was an important rate-limiting step. The adsorption isotherms of both drugs were fit well with Freundlich model. The adsorption of CA onto RSB was exothermic and was more likely to be dominated by physical processes, while the adsorption of CBZ was endothermic. Solution pH was determined to be the most important factor for CA adsorption, such that the adsorption capacity of CA onto RSB increased with the decline of solution pH. In the lower range of solution pH below 3.1, the CA removal efficiency was enhanced with the increase of biosorbent dosage. The CBZ removal efficiency was enhanced with the increase of RSB dosage without pH control. The maximum adsorption capacities were 126.3 mg/g for CA and 40.0 mg/g for CBZ.

Removal of Carbamazepine from Water by a Novel TiO2–Coconut Shell Powder/UV Process: Composite Preparation and Photocatalytic Activity

A novel TiO2-coconut shell powder (TCNSP) composite, prepared by the controlled sol-gel method with a subsequent heat treatment, was investigated as an innovative photocatalytic absorbent for the removal of carbamazepine (CBZ). CBZ is used worldwide as an antiepileptic drug, which has recently been recognized as an important organic pollutant increasingly found in wastewaters from urban areas and other aquatic environments. The granulation process was performed by using a semiautomated mass production line to produce sufficient quantities of TCNSP composites, possessing sufficient crush strength for commercialization. Physical properties of the TCNSP composite such as crystallinity, morphology, crush strength, and the Brunauer-Emmett-Teller (BET)-specific surface area were controlled by the mass ratio of titanium dioxide sol and coconut shell powder (CNSP). Calcination at 700°C produced anatase phase TiO2 in the TCNSP composites with a BET high surface area of 454 m2/g. Anatase crystallite size of the TCNSP composite increased from 2.37 to 15.11 nm with increasing calcination temperature from 500°C to 800°C. Calcinated TCNSP composites had higher CBZ removal efficiency (98%) than pure TiO2 (23%) and CNSP (34%) within a 40-min reaction time. Optimization of this innovative adsorption/photocatalytic process was obtained by a response surface methodology and a central composite design model, which indicated that this novel and sustainable technology was successful in removing CBZ from a solution.

Carbamazepine Removal from Groundwater: Effectiveness of the TiO2/UV, Nanoparticulate Zero‐Valent Iron, and Fenton (NZVI/H2O2) Processes

AbstractPharmaceutical compounds, widely produced and used all around the world, are partly responsible for the widespread water pollution in the environment. Carbamazepine (CBZ) is an antiepileptic drug that persists in the environment for many years. In the present study, we used the TiO2/UV, nanoparticulate zero‐valent iron (NZVI), and NZVI/H2O2 treatment processes to compare efficiency of CBZ removal from water. Influence of NZVI loading, H2O2 concentration, TiO2 loading, UV lamp power, and the matrix (distilled water and groundwater) on CBZ removal efficiency was evaluated using full factorial design. Results indicated that the NZVI/H2O2 process oxidized CBZ within 5 min. On the other hand, the NZVI process alone did not reduce CBZ concentration after 120 min of process time. The NZVI/H2O2 process was equally effective in CBZ removal from both distilled water and groundwater whereas the TiO2/UV process was less effective due to the presence of ions in groundwater. CBZ removal efficiency of the TiO2/UV process declined 30% when the matrix was changed from distilled water to groundwater. Negative divalent ions, i.e., ${\rm SO}_{{\rm 4}}^{{\rm 2}- } $ and ${\rm CO}_{{\rm 3}}^{{\rm 2}- } $, were the main cause of reduction of CBZ removal efficiency from groundwater. It is likely that these two ions adsorb onto, and consequently prevent the superoxide anion ${\rm O}_{{\rm 2}}^{\bullet - } $ and hydroxyl radical OH• from being generated on, the surface of the TiO2.

Comparative study of the degradation of carbamazepine in water by advanced oxidation processes

Degradation of carbamazepine (CBZ) using ultraviolet (UV), UV/H2O2, Fenton, UV/Fenton and photocatalytic oxidation with TiO2 (UV/TiO2) was studied in deionized water. The five different oxidation processes were compared for the removal kinetics of CBZ. The results showed that all the processes followed pseudo-first-order kinetics. The direct photolysis (UV alone) was found to be less effective than UV/H2O2 oxidation for the degradation of CBZ. An approximate 20% increase in the CBZ removal efficiency occurred with the UV/Fenton reaction as compared with the Fenton oxidation. In the UV/TiO2 system, the kinetics of CBZ degradation in the presence of different concentrations of TiO2 followed the pseudo-first order degradation, which was consistent with the Langmuir–Hinshelwood (L–H) model. On a time basis, the degradation efficiencies of CBZ were in the following order: UV/Fenton (86.9%±1.7% )>UV/TiO2 (70.4%±4.2% )>Fenton (67.8%±2.6% )>UV/H2O2 (40.65±5.1% )>UV (12.2%±1.4% ). However, the lowest cost was obtained with the Fenton process.

Removal of carbamazepine and sulfamethoxazole by MBR under anoxic and aerobic conditions

This study reveals for the first time that near-anoxic conditions (dissolved oxygen, DO=0.5mg/L) can be a favorable operating regime for the removal of the persistent micropollutant carbamazepine by MBR treatment. The removal efficiencies of carbamazepine and sulfamethoxazole by an MBR were systematically examined and compared under near-anoxic (DO=0.5mg/L) and aerobic (DO>2mg/L) conditions. Preliminary batch tests confirmed that sulfamethoxazole is amenable to both aerobic and anoxic biotransformation. However, carbamazepine—a known persistent compound—showed degradation only under an anoxic environment. In good agreement with the batch tests, during near-anoxic operation, under a high loading of 750μg/Ld, an exceptionally high removal (68±10%) of carbamazepine was achieved. In contrast, low removal efficiency (12±11%) of carbamazepine was observed during operation under aerobic conditions. On the other hand, an average removal efficiency of 65% of sulfamethoxazole was achieved irrespective of the DO concentrations.

Pharmaceuticals, hormones and bisphenol A in untreated source and finished drinking water in Ontario, Canada — Occurrence and treatment efficiency

The Ontario Ministry of the Environment (MOE) conducted a survey in 2006 on emerging organic contaminants (EOCs) which included pharmaceuticals, hormones and bisphenol A (BPA). The survey collected 258 samples over a 16month period from selected source waters and 17 drinking water systems (DWSs), and analyzed them for 48 EOCs using liquid chromatography–tandem mass spectrometry (LC-MS/MS) and isotope dilution mass spectrometry (IDMS) for the highest precision and accuracy of analytical data possible. 27 of the 48 target EOCs were detected in source water, finished drinking water, or both. DWSs using river and lake source water accounted for>90% detections. Of the 27 EOCs found, we also reported the first detection of two antibiotics roxithromycin and enrofloxacin in environmental samples. The most frequently detected compounds (≥10%) in finished drinking water were carbamazepine (CBZ), gemfibrozil (GFB), ibuprofen (IBU), and BPA; with their concentrations accurately determined by using IDMS and calculated to be 4 to 10 times lower than those measured in the source water. Comparison of plant specific data allowed us to determine removal efficiency (RE) of these four most frequently detected compounds in Ontario DWSs. The RE of CBZ was determined to be from 71 to 93% for DWSs using granulated activated carbon (GAC); and was 75% for DWSs using GAC followed by ultraviolet irradiation (UV). The observed RE of GFB was between 44 and 55% in DWSs using GAC and increased to 82% when GAC was followed by UV. The use of GAC or GAC followed by UV provided an RE improvement of BPA from 80 to 99%. These detected concentration levels are well below the predicted no effect concentration or total allowable concentration reported in the literature. Additional targeted, site specific comparative research is required to fully assess the effectiveness of Ontario DWSs to remove particular compounds of concern.

The characteristics of enriched nitrifier culture in the degradation of selected pharmaceutically active compounds

The biodegradation of 10 selected pharmaceuticals by enriched nitrifier cultures with ammonia oxidizing activity of 30 mg NH 4-N/g MLVSS h was investigated under various initial operating conditions such as in the presence of different growth substrates and inhibitors. The enriched nitrifier culture showed higher degradation of the target pharmaceuticals than the conventional activated sludge. The degradation efficiency of persistent pharmaceuticals such as clofibric acid (CA), diclofenac (DCF), carbamazepine (CBZ), and propyphenazone (PPZ) was increased with the increase in the ammonium concentration. A higher removal efficiency of CA, DCF, CBZ and PPZ was obtained when organic substrates were added. The contribution of autotrophs and heterotrophs in the biotransformation of the pharmaceuticals by the enriched nitrifier culture was successfully estimated by the addition of inhibitors. Experimental results showed that the high degradation of IBP and partial degradation of other selected pharmaceuticals were observed in the presence of allylthiourea (ATU), an ammonia monooxygenase inhibitor, reflecting the activity of heterotrophic bacteria, while the results with and without ATU addition showed that the contribution of the nitrification in the degradation of most pharmaceuticals was also dominant. The results suggest that nitrification can enhance the biotransformation of pharmaceutical substances.

Removal efficiency of 66 pharmaceuticals during wastewater treatment process in Japan

Both biological treatment processes including conventional activated sludge (CAS) and biological nutrient removal (BNR) processes, and physico-chemical treatment processes including ozonation process and Title 22 process consisting of coagulation, sedimentation and filtration followed by UV or chlorination disinfection after the above biological processes, were compared from the viewpoint of removal efficiency. 66 pharmaceuticals including antibiotics, analgesics, psychoneurotic agents were measured with SPE-LC/MS/MS. 26 compounds out of 66 were detected in the influent ranging ng/L to microg/L order. Particularly, disopyramide, sulpiride, and dipyridamole that have been rarely detected before in the WWTP, occurred at concentration levels of more than 100 ng/L. The total concentration of the individual pharmaceuticals in the influent was efficiently removed by 80% during the biological treatment. But removal efficiencies of carbamazepine and crotamiton were less than 30%. The total concentration of the individual pharmaceuticals in the effluent from CAS process was 1.5 times higher than that from BNR process. Further, the total concentration of the individual pharmaceuticals in the discharge from WWTPs applying ozonation following activated sludge process was reduced to less than 20%. Physico-chemical treatment train called Title 22 treatment after CAS could not efficiently remove the pharmaceuticals. However, ozonation process followed by biological activated carbon process could efficiently reduce all the residual pharmaceuticals below their quantification limits.