Removal Of Clofibric Acid Research Articles

Shear-induced hydrodynamic cavitation as a tool for pharmaceutical micropollutants removal from urban wastewater

In this study, the removal of clofibric acid, ibuprofen, naproxen, ketoprofen, carbamazepine and diclofenac residues from wastewater, using a novel shear-induced cavitation generator has been systematically studied. The effects of temperature, cavitation time and H2O2 dose on removal efficiency were investigated. Optimisation (50°C; 15min; 340mgL−1 of added H2O2) resulted in removal efficiencies of 47–86% in spiked deionised water samples. Treatment of actual wastewater effluents revealed that although matrix composition reduces removal efficiency, this effect can be compensated for by increasing H2O2 dose (3.4gL−1) and prolonging cavitation time (30min). Hydrodynamic cavitation has also been investigated as either a pre- or a post-treatment step to biological treatment. The results revealed a higher overall removal efficiency of recalcitrant diclofenac and carbamazepine, when hydrodynamic cavitation was used prior to as compared to post biological treatment i.e., 54% and 67% as compared to 39% and 56%, respectively. This is an important finding since diclofenac is considered as a priority substance to be included in the EU Water Framework Directive.

Removal of clofibric acid and diclofenac during anaerobic digestion of sewage sludge

Removal of clofibric acid and diclofenac during anaerobic digestion of sewage sludge

Influence Parameters in the Ozonation of Clofibric Acid Using a Cascade Bubble Column

Ozonation of clofibric acid (CA) in aqueous solution was carried out under continuous operation in a cascade bubble column. The influence of operation parameters including initial CA concentration, gas flow rate, liquid flow rate and pH on the removal of CA and TOC was investigated. The results indicated that ozonation could be used to effectively remove CA from water. Increasing the initial CA concentration resulted in a decrease of the CA and TOC removal efficiency. A comparison of CA removal efficiency and ozone utilization between cascade and conventional bubble column indicated that cascade bubble column was an effective way for increasing the solubility ozone in the reactor.

Evaluation of aquatic plants for removing polar microcontaminants: A microcosm experiment

Microcosm wetland systems (5 L containers) planted with Salvinia molesta, Lemna minor, Ceratophyllum demersum, and Elodea canadensis were investigated for the removal of diclofenac, triclosan, naproxen, ibuprofen, caffeine, clofibric acid and MCPA. After 38days of incubation, 40–99% of triclosan, diclofenac, and naproxen were removed from the planted and unplanted reactors. In covered control reactors no removal was observed. Caffeine and ibuprofen were removed from 40% to 80% in planted reactors whereas removals in control reactors were much lower (2–30%). Removal of clofibric acid and MCPA were negligible in both planted and unplanted reactors. The findings suggested that triclosan, diclofenac, and naproxen were removed predominantly by photodegradation, whereas caffeine and naproxen were removed by biodegradation and/or plant uptake. Pseudo-first-order removal rate constants estimated from nonlinear regressions of time series concentration data were used to describe the contaminant removals. Removal rate constants ranged from 0.003 to 0.299d−1, with half-lives from 2 to 248days. The formation of two major degradation products from ibuprofen, carboxy-ibuprofen and hydroxy-ibuprofen, and a photodegradation product from diclofenac, 1-(8-Chlorocarbazolyl)acetic acid, were followed as a function of time. This study emphasizes that plants contribute to the elimination capacity of microcontaminants in wetlands systems through biodegradation and uptake processes.

UV and VUV photolysis vs. UV/H2O2 and VUV/H2O2 treatment for removal of clofibric acid from aqueous solution

Clofibric acid (CA), a metabolite of lipid regulators, was investigated in ultra‐pure water and sewage treatment plant (STP) effluent at 10 °C under UV, vacuum UV (VUV), UV/H2O2 and VUV/H2O2 processes. The influences of NO3 −, HCO3 − and humic acid (HA) on CA photolysis in all processes were examined. The results showed that all the experimental data well fitted the pseudo‐first‐order kinetic model, and the apparent rate constant (kap ) and half‐life time (t1/2 ) were calculated accordingly. Direct photolysis of CA through UV irradiation was the main process, compared with the indirect oxidation of CA due to the slight generation of hydroxyl radicals dissociated from water molecules under UV irradiation below 200 nm monochromatic wavelength emission. In contrast, indirect oxidation was the main CA degradation mechanism in UV/H2O2 and VUV/H2O2, and VUV/H2O2 was the most effective process for CA degradation. The addition of 20 mg L−1 HA could significantly inhibit CA degradation, whereas, except for UV irradiation, the inhibitive effects of NO3 − and HCO3 − (1.0 × 10−3 and 0.1 mol L−1, respectively) on CA degradation were observed in all processes, and their adverse effects were more significant in UV/H2O2 and VUV/H2O2 processes, particularly at the high NO3 − and HCO3 − concentrations. The degradation rate decreased 1.8–4.9‐fold when these processes were applied to a real STP effluent owing to the presence of complex constituents. Of the four processes, VUV/H2O2 was the most effective, and the CA removal efficiency reached over 99% after 40 min in contrast to 80 min in both the UV/H2O2 and VUV processes and 240 min in the UV process.

Photocatalysis of Clofibric Acid under Solar Light in Summer and Winter Seasons

The performance of clofibric acid (CA) degradation in Milli-Q water and wastewater treatment plant (WWTP) effluent by solar/TiO2 and solar/ZnO was investigated in summer and winter seasons. The effects of NO3− and HCO3− anions, humic acid (HA), and H2O2 on CA photocatalysis were evaluated. Significant difference in CA degradation in two seasons was observed. Both NO3− and HCO3− anions adversely affected CA degradation, particularly at high HCO3− concentration. CA degradation slightly increased with 0.5 mg L−1 HA in solar/TiO2 in summer, but was significantly inhibited in winter at 20 mg L−1 HA. However, the inhibitive effect of 20 mg L−1 HA on CA removal in solar/ZnO had no remarkable difference in two seasons. The degradation in solar/TiO2/H2O2 was similar to that in solar/TiO2, but was inhibited obviously in solar/ZnO/H2O2. When applying photocatalytic process into WWTP effluent, degradation rates were apparently lower compared to Milli-Q water and temperature caused a great adverse effect on CA elimination.

Clofibric acid degradation in UV 254/H 2O 2 process: Effect of temperature

The degradation of clofibric acid (CA) in UV 254/H 2O 2 process under three temperature ranges, i.e. T1 (9.0–11.5 °C), T2 (19.0–21.0 °C) and T3 (29.0–30.0 °C) was investigated. The effects of solution constituents including NO 3 − and HCO 3 − anions, and humic acid (HA) on CA degradation were evaluated in Milli-Q waters. CA degradation behaviors were simulated with the pseudo-first-order kinetic model and the apparent rate constant ( k ap ) and half-life time ( t 1/2) were calculated. The results showed that higher temperature would favor CA degradation, and CA degradation was taken place mostly by indirect oxidation through the formation of OH radicals in UV 254/H 2O 2 process. In addition, the effects of both NO 3 − and HCO 3 − anions at two selected concentrations (1.0 × 10 −3 and 0.1 mol L −1) and HA (20 mg L −1) on CA degradation were investigated. The results showed that HA had negative effect on CA degradation, and this effect was much more apparent under low temperature condition. On the other hand, the inhibitive effect on CA degradation at both lower and higher concentrations of bicarbonate was observed, and this inhibitive effect was much more apparent at higher bicarbonate concentration and lower temperature condition. While, at higher nitrate concentration the inhibitive effect on CA degradation under three temperature ranges was observed, and with the temperature increase this negative effect was apparently weakened. However, at lower nitrate concentration a slightly positive effect on CA degradation was found under T2 and T3 conditions. Moreover, when using a real wastewater treatment plant (WWTP) effluent spiked with CA over 99% of CA removal could be achieved under 30 °C within only 15 min compared with 40 and 80 min under 20 and 10 °C respectively, suggesting a significant promotion in CA degradation under higher temperature condition. Therefore, it can be concluded that temperature plays an important role in CA degradation in UV/H 2O 2 process.

Photo-degradation of clofibric acid by ultraviolet light irradiation at 185 nm

As a metabolite of lipid regulators, clofibric acid (CA) was investigated in this study for its ultraviolet (UV) degradation at monochromatic wavelength of 185 nm using Milli-Q water and sewage treatment plant (STP) effluent. The effects of CA initial concentration, solution pH, humic acid (HA), nitrate and bicarbonate anions on CA degradation performances were evaluated. All CA degradation patterns well fitted the pseudo-first-order kinetic model. The results showed that OH generated from water photolysis by UV185 irradiation was involved, resulting in indirect CA photolysis but contributed less to the whole CA removal when compared to the main direct photolysis process. Acid condition favored slightly to CA degradation and other constituents in solution, such as HA (5.0-100.0 mg L(-1)), nitrate and bicarbonate anions (1.0x10(-3) mol L(-1) and 0.1 mol L(-1)), had negative effects on CA degradation. When using real STP effluent CA degradation could reach 97.4% (without filtration) and 99.3% (with filtration) after 1 hr irradiation, showing its potential mean in pharmaceuticals removal in UV disinfection unit. Mineralization tests showed that rapid chloride ion release happened, resulting in no chlorinated intermediates accumulation, and those non-chlorinated intermediate products could further be nearly completely degraded to CO2 and H2O after 6 hrs.

Effect of solution pH on the removal of clofibric acid by cork-based activated carbons

Clofibric acid adsorption from the aqueous phase was studied using cork-based activated carbons (CAC: chemically activated with K 2CO 3; CPAC: physical activation of sample CAC with steam). CPAC outperformed the uptake of water treatment commercial carbons. Results highlight the importance of pH in clofibric acid adsorption: the highest removals were obtained for pH 2.0 and decrease for higher pHs. The sigmoidal adsorption isotherms obtained were fitted to the Dubinin–Astakhov equation. The characteristic adsorption energy revealed that CAC has the highest affinity for the solute, in accordance with its narrow micropore size distribution. The molecular and electronic structure showed that the solvation energy of the undissociated and dissociated forms of clofibric acid is the key factor to explain the isotherm shape and the dependence of the pH. For pH 3.6 the dissociated form is dominant and the uptake significantly decreases, showing that the solvent shields the interaction of the dissociated specie (higher solvation energy) with the carbon surface. The results show that once the solvation energies of the undissociated and dissociated forms of clofibric acid are known, a complete characterization of an activated carbon allows one to predict with confidence its behavior for the adsorption of this compound from the aqueous phase.

Ozonation of clofibric acid catalyzed by titanium dioxide

The removal of clofibric acid from aqueous solution has been investigated in catalytic and non-catalytic semicontinuous ozonation runs. Kinetic data were analyzed using second order expressions for the reaction between organics and ozone or hydroxyl radicals. Catalytic runs used a commercial titanium dioxide catalyst consisting of fumed colloidal particles. The kinetic constant of the non-catalytic ozonation of clofibric acid at pH 3 was 8.16 × 10 −3 ± 3.4 × 10 −4 L mmol −1 s −1. The extent of mineralization during non-catalytic runs ranged from 50% at pH 7 to 20% at pH 3 in a reaction that essentially took place during the first 10–20 min. The catalyst increased the total extent of mineralization, its effect being more important during the first part of the reaction. The pseudo-homogeneous catalytic rate constant was 2.17 × 10 −2 L mmol −1 s −1 at pH 3 and 6.80 × 10 −1 L mmol −1 s −1 at pH 5, with up to a threefold increase with respect to non-catalytic constants using catalyst load of 1 g/L. A set of stopped-flow experiments were designed to elucidate the role of catalyst, whose effect was probably due to the adsorption of organics on catalytic sites rather than to the promotion of ozone decomposition.

Preliminary media screening for application in the removal of clofibric acid, carbamazepine and ibuprofen by SSF-constructed wetlands

The aim of the present work was to evaluate the sorption capacity of light expanded clay aggregates (LECA) to remove mixtures of ibuprofen, carbamazepine and clofibric acid in water and wastewater. High removal efficiencies were attained for carbamazepine and ibuprofen while a less satisfactory performance was observed for clofibric acid. In a mixture of the three compounds in water a slight decrease in the sorbed amounts is observed in comparison with solutions of the single compounds, indicating some competitive sorption. In wastewater, the pharmaceuticals mixture also undergoes a slight reduction in the sorbed amounts of carbamazepine and ibuprofen, probably due to the presence of dissolved organic matter which increases their solubility. These compounds were removed in the following order of efficiencies in all the tested conditions: carbamazepine > ibuprofen > clofibric acid. Two other clay materials – sepiolite and vermiculite – were tested for the removal of the more recalcitrant clofibric acid, and vermiculite exhibited higher removal efficiency than LECA. The sorption is characterized by an initial fast step, with most pharmaceuticals being removed within the first 24 h. The results of this study are a first step in the process of selecting an appropriate material or combination of materials to be used as media in SSF-CWs designed for the removal of pharmaceuticals from wastewaters.

Photolysis and advanced oxidation treatment of pharmaceuticals in tap water and treated sewage

The aim of this study was to investigate the removal efficiency of six phannaceuticals byphoto-degradation and the advanced oxidation process (AOP), UV/H2O2. The sixphannaceuticals were the four NSAIDs ibuprofen, diclofenac, naproxen and ketoprofen, thepharmacological active metabolite of the lipid lowering agent, clofibrin, clofibric acid, and theanticonvulsant and mood stabilizing drug, carbamazepine.Treatment experiments were perfom1ed using a UV lamp optimized for photochemicaltreatment in a flow through set-up. For the AOP experiments 60 mg/L H2O2 was added to thewater before treatment. The treatment effectiveness is evaluated based on the ElectricalEnergy per Order (EEO) (unit kWh!m\ which is defined as the electrical energy consumedper unit volume of water treated required for 90% removal of the investigated compound.It was found that four of the six phannaceuticals were completely removed in tap water byboth UV treatment and the AOP. The exceptions were ibuprofen and carbamazepine, whichexhibited a relationship between UV dose and removal. The electrical energy per order, EEOwas detennined to 8.2 kWh/ml (UV) and 3. 7 kWh/ml (UV /H2O2 ) for ibuprofen.In the wastewater effluent the removal by UV irradiation was almost complete for ketoprofen,while the other compounds show dependency of flow rate/UV dose. Ibuprofen was thecompound that needed the highest UV dose to remove 90% (EEO = 33.4 kWh/ml) wherenaproxen and clofibric acid required 9.6 kWh/ml and 5.5 kWh/ml, respectively. Ketoprofenand diclofenac needed considerable less energy than clofibric acid. Ibuprofen and naproxen isbiodegradable and will be removed in biologically treated wastewater. Therefore, the relevantestimate of the needed treatment is the energy use for removal of clofibric acid which required5.5 kWh/ml for 90% removal.