Degradation Of Clofibric Acid Research Articles

Mechanism for enhanced degradation of clofibric acid in aqueous by catalytic ozonation over MnOx/SBA-15

Comparative experiments were conducted to investigate the catalytic ability of MnOx/SBA-15 for the ozonation of clofibric acid (CA) and its reaction mechanism. Compared with ozonation alone, the degradation of CA was barely enhanced, while the removal of TOC was significantly improved by catalytic ozonation (O3/MnOx/SBA-15). Adsorption of CA and its intermediates by MnOx/SBA-15 was proved unimportant in O3/MnOx/SBA-15 due to the insignificant adsorption of CA and little TOC variation after ceasing ozone in stopped-flow experiment. The more remarkably inhibition effect of sodium bisulfite (NaHSO3) on the removal of TOC in catalytic ozonation than in ozonation alone elucidated that MnOx/SBA-15 facilitated the generation of hydroxyl radicals (OH), which was further verified by electron spin-resonance spectroscopy (ESR). Highly dispersed MnOx on SBA-15 were believed to be the main active component in MnOx/SBA-15. Some intermediates were indentified and different degradation routes of CA were proposed in both ozonation alone and catalytic ozonation. The amounts of small molecular carboxylic acids (i.e., formic acid (FA), acetic acid (AA) and oxalic acid (OA)) generated in catalytic ozonation were lower than in ozonation alone, resulting from the generation of more OH.

FeOOH and derived phases: Efficient heterogeneous catalysts for clofibric acid degradation by advanced oxidation processes (AOPs)

In this study the degradation of an aqueous solution of clofibric acid was investigated during catalytic ozonation and Fenton-like process with FeOOH – derived catalysts. From the different calcination temperatures tested, it has been observed that the most active catalyst is the commercial FeOOH calcined at 200°C, when maghemite and hematite are the predominant phases obtained. The best result, at room temperature, for CFA mineralization was observed over 0.5wt% Pd on FeOOH (calcined at 200°C) among all tested catalysts, achieving 68% and 81% mineralization degree, in 2h and 6h, respectively, in catalytic ozonation and 66% and 71% of mineralization degree within 2h and 6h, respectively for Fenton process. The efficiency of the Fenton-like process is enhanced at higher temperature (40–60°C), reaching a mineralization degree up to 82% in 6h. Furthermore, Pd impregnation on FeOOH increased the catalyst stability.

Reactions of clofibric acid with oxidative and reductive radicals—Products, mechanisms, efficiency and toxic effects

The degradation of clofibric acid induced by hydroxyl radical, hydrated electron and O2−∙/HO2∙ reactive species was studied in aqueous solutions. Clofibric acid was decomposed more effectively by hydroxyl radical than by hydrated electron or O2−∙/HO2∙. Various hydroxylated, dechlorinated and fragmentation products have been identified and quantified. A new LC–MS method was developed based on 18O isotope labeling to follow the formation of hydroxylated derivatives of clofibric acid. Possible degradation pathways have been proposed. The overall degradation was monitored by determination of sum parameters like COD, TOC and AOX. It was found that the organic chlorine degrades very effectively prior to complete mineralization. After the treatment no toxic effect was found according to Vibrio fischeri tests. However, at early stages some of the reaction products were more harmful than clofibric acid.

Kinetic modeling of the photocatalytic degradation of clofibric acid in a slurry reactor

A kinetic study of the photocatalytic degradation of the pharmaceutical clofibric acid is presented. Experiments were carried out under UV radiation employing titanium dioxide in water suspension. The main reaction intermediates were identified and quantified. Intrinsic expressions to represent the kinetics of clofibric acid and the main intermediates were derived. The modeling of the radiation field in the reactor was carried out by Monte Carlo simulation. Experimental runs were performed by varying the catalyst concentration and the incident radiation. Kinetic parameters were estimated from the experiments by applying a non-linear regression procedure. Good agreement was obtained between model predictions and experimental data, with an error of 5.9 % in the estimations of the primary pollutant concentration.

Degradation of clofibric acid in aqueous solution by an EC/Fe3+/PMS process

Abstract The removal of clofibric acid (CA) in aqueous solution by ferrous ion activated peroxymonosulfate (PMS) oxidation in an electrochemical reactor (EC/Fe3+/PMS) was performed in this study. The process involved the use of a dimensionally stable anode (DSA) and a stainless steel cathode. Ferrous ion was produced from cathodic reduction of externally applied ferric ion and activated PMS for the generation of sulfate radicals ( SO 4 - ). Various parameters were investigated to optimize the process, including PMS concentration, Fe3+ concentration and current density. The results indicated that the removal efficiency increased with the increase of PMS concentration, Fe3+ concentration and current density. The scavenging effect was examined by using ethanol (EtOH) and tert-butyl alcohol (t-BuOH) to identify the reactive radicals in EC/Fe3+/PMS process. The TOC removal efficiency was 30.8% in 60 min reaction, and it reached 64.7% when the reaction time was extended to 180 min. The GC–MS analysis was employed to identify the intermediate products and a plausible degradation pathway was proposed.

Clofibric acid degradation by catalytic ozonation using hydrotalcite-derived catalysts

The degradation of an aqueous solution of clofibric acid was investigated during catalytic ozonation. Mg/Al hydrotalcite (HT) catalysts containing Fe, Cu, and Ni, and spinel-type materials CuAl2O4 and CuMgAl2O4 were prepared by co-precipitation method, calcined and used for the ozonation reaction of clofibric acid. The combination of ozone and HT catalysts was effective for the removal of total organic carbon (TOC). MgCuAl HT and CuMgAl2O4 showed the highest activity, followed by MgFeAl and MgNiAl. The best result of clofibric acid mineralization concerning activity and stability was observed over Mg3Fe0.5Al1 HT catalyst calcined at 900°C with no leaching of Fe, and Cu0.75Mg0.5Al2O4 catalyst after pretreatment with 2% of oxalic acid calcined at 950°C, with which least leaching of Cu metal was detected. With these materials, up to 70 and 80% of mineralization degree, respectively, was achieved. These materials have shown to be stable after reuse. Also XRD analyses of used catalysts showed similar crystallographic structures than fresh materials. The efficiency of the process is mainly attained by a heterogeneous radical based mechanism, and not significantly affected by initial pH of solution.

Identification and ecotoxicity assessment of intermediates generated during the degradation of clofibric acid by advanced oxidation processes

The aim of this study was to identify the intermediates in clofibric acid degradation under various advanced oxidation processes, namely ultraviolet (UV), UV/H2O2, vacuum ultraviolet (VUV), VUV/H2O2, and solar/TiO2 processes, as well as to assess the toxicity of these intermediates. Eleven intermediates have been detected by gas chromatography-mass spectrometer, most of which were reported for the first time to our best knowledge. Combining the evolution of the dissolved organic carbon, Cl− and specific ultraviolet absorption at 254 nm, it could be deduced that cleavage of aromatic ring followed by dechlorination was the mechanism in solar/TiO2 process, while dechlorination happened first and accumulation of aromatic intermediates occurred in the other processes. Different transformation pathways were proposed for UV-, VUV-assisted and solar/TiO2 processes, respectively. The acute toxicity was evaluated by means of Photobacterium phosphoreum T3 spp. bioassay. It was believed that aromatic intermediates increased the toxicity and the ring-opening pathway in solar/TiO2 process could relieve the toxicity.

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.

Enhanced Cu activity in catalytic ozonation of clofibric acid by incorporation into ammonium dawsonite

Clofibric acid (CFA) degradation by ozonation in the presence of Cu-dawsonites was studied. Cu-dawsonite materials were synthesized via co-precipitation of Al(NO3)3 and Cu(NO3)2 by (NH4)2CO3 at pH 7.5–8.0. The as-synthesized and the calcined samples were characterized using XRD, FTIR, N2-physisorption, TEM and XPS techniques. The CFA degradation was carried out using the as-synthesized and the calcined Cu-dawsonites, dissolved Cu2+ and CuO supported on Al2O3. The heterogeneous as-synthesized Cu-dawsonite catalysts showed more efficient performance with respect to the other catalysts, despite of significant Cu leaching detected at the end of the reactions. The reactions carried out using the homogeneous dissolved Cu2+ (in the concentration range of the leached Cu) indicated low contribution of dissolved Cu2+ in the mineralization of CFA and its intermediates; the efficiency was mainly devoted to the activity of Cu incorporated in the dawsonite structure. Characterization of Cu-dawsonites revealed a possibility of Cu localization in the NH4+ position, which is higher exposed to leaching than that of Al. The reaction performed at initial pH 10 (pH higher than pHPZC of as-synthesized Cu-dawsonite) resulted to a higher TOC and COD reduction after 2h compared with the reaction at pH 3.7. Also lowest Cu leaching was obtained under these conditions. Enhanced activity of Cu incorporated into the structure of dawsonite in the catalytic ozonation of CFA is probably due to the presence of Cu(I) located in the structure of dawsonite revealed by XPS. Some of the main intermediates have been identified by HPLC–MS suggesting three routes for CFA destruction by ozonation using Cu-dawsonite including, C1–O and C4–Cl bond breaking and aromatic ring cleavage.

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.

Photocatalytic degradation of clofibric acid, carbamazepine and iomeprol using conglomerated TiO2 and activated carbon in aqueous suspension

The combination of powdered activated carbon (PAC) and TiO(2) has been tested for synergistic/antagonistic effects in the photocatalytic degradation of carbamazepine, clofibric acid and iomeprol. Synergistic effects are thought to be caused by rapid adsorption on the PAC surface followed by diffusion to the TiO(2) surface and photocatalytic degradation. The Freundlich constant K(F) was used for comparing the sorption properties of the three substances and it was found that K(F) for clofibric acid was 3 times lower than for carbamazepine and iomeprol, regardless of the kind of PAC used. A PAC with a distinct tendency to form conglomerates was selected so that a high percentage of the PAC surface was in direct proximity to the TiO(2) surface. The photocatalytic degradation of the pharmaceutically active compounds studied followed pseudo-first order kinetics. Synergistic effects only occurred for clofibric acid (factor 1.5) and an inverse relationship between adsorption affinity and synergistic effects was found. High affinity of the target substances to the PAC surface seemed to be counterproductive for the photocatalytic degradation.

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.

Anatase vs. rutile efficiency on the photocatalytic degradation of clofibric acid under near UV to visible irradiation

Titanium dioxide (TiO(2)) powder, a semiconductor material typically used as a photocatalyst, is prepared following an acid-catalyzed sol-gel method starting from titanium isopropoxide. The xerogel calcination temperature is used to control surface and morphological properties of the material. Materials are extensively characterized by spectroscopic, micrographic and calorimetric techniques. The different TiO(2) catalysts are used in the visible-light-driven photocatalytic degradation of clofibric acid, a lipid regulator drug. The photoefficiency of TiO(2) catalysts, quantified in terms of kinetic rate constant, total organic carbon removal and initial quantum yield, increases with calcination temperature up to 673 K. A further increase in the calcination temperature leads to a decline in the photoefficiency of the catalysts, which is associated with the phase transformation from anatase to rutile concomitant with an increase in crystallite dimensions. The photochemical and photocatalytic oxidation of clofibric acid follows a pseudo-first order kinetic rate law. 4-Chlorophenol, isobutyric acid, hydroquinone, benzoquinone and 4-chlorocatechol are detected as main intermediates.

Degradation of clofibric acid in acidic aqueous medium by electro-Fenton and photoelectro-Fenton

Acidic aqueous solutions of clofibric acid (2-(4-chlorophenoxy)-2-methylpropionic acid), the bioactive metabolite of various lipid-regulating drugs, have been degraded by indirect electrooxidation methods such as electro-Fenton and photoelectro-Fenton with Fe 2+ as catalyst using an undivided electrolytic cell with a Pt anode and an O 2-diffusion cathode able to electrogenerate H 2O 2. At pH 3.0 about 80% of mineralization is achieved with the electro-Fenton method due to the efficient production of oxidant hydroxyl radical from Fenton’s reaction between Fe 2+ and H 2O 2, but stable Fe 3+ complexes are formed. The photoelectro-Fenton method favors the photodecomposition of these species under UVA irradiation, reaching more than 96% of decontamination. The mineralization current efficiency increases with rising metabolite concentration up to saturation and with decreasing current density. The photoelectro-Fenton method is then viable for treating acidic wastewaters containing this pollutant. Comparative degradation by anodic oxidation (without Fe 2+) yields poor decontamination. Chloride ion is released during all degradation processes. The decay kinetics of clofibric acid always follows a pseudo-first-order reaction, with a similar rate constant in electro-Fenton and photoelectro-Fenton that increases with rising current density, but decreases at greater metabolite concentration. 4-Chlorophenol, 4-chlorocatechol, 4-chlororesorcinol, hydroquinone, p-benzoquinone and 1,2,4-benzenetriol, along with carboxylic acids such as 2-hydroxyisobutyric, tartronic, maleic, fumaric, formic and oxalic, are detected as intermediates. The ultimate product is oxalic acid, which forms very stable Fe 3+-oxalato complexes under electro-Fenton conditions. These complexes are efficiently photodecarboxylated in photoelectro-Fenton under the action of UVA light.

Electrochemical degradation of clofibric acid in water by anodic oxidation: Comparative study with platinum and boron-doped diamond electrodes

Aqueous solutions containing the metabolite clofibric acid (2-(4-chlorophenoxy)-2-methylpropionic acid) up to close to saturation in the pH range 2.0–12.0 have been degraded by anodic oxidation with Pt and boron-doped diamond (BDD) as anodes. The use of BDD leads to total mineralization in all media due to the efficient production of oxidant hydroxyl radical (OH). This procedure is then viable for the treatment of wastewaters containing this compound. The effect of pH, apparent current density, temperature and metabolite concentration on the degradation rate, consumed specific charge and mineralization current efficiency has been investigated. Comparative treatment with Pt yields poor decontamination with complete release of stable chloride ion. When BDD is used, this ion is oxidized to Cl2. Clofibric acid is more rapidly destroyed on Pt than on BDD, indicating that it is more strongly adsorbed on the Pt surface enhancing its reaction with OH. Its decay kinetics always follows a pseudo-first-order reaction and the rate constant for each anode increases with increasing apparent current density, being practically independent of pH and metabolite concentration. Aromatic products such as 4-chlorophenol, 4-chlorocatechol, 4-chlororesorcinol, hydroquinone, p-benzoquinone and 1,2,4-benzenetriol are detected by gas chromatography–mass spectrometry (GC–MS) and reversed-phase chromatography. Tartronic, maleic, fumaric, formic, 2-hydroxyisobutyric, pyruvic and oxalic acids are identified as generated carboxylic acids by ion-exclusion chromatography. These acids remain stable in solution using Pt, but they are completely converted into CO2 with BDD. A reaction pathway for clofibric acid degradation involving all these intermediates is proposed.

Removal of selected persistent organic pollutants by heterogeneous photocatalysis in water

Environmentally relevant polar persistent organic pollutants (pharmaceuticals and diagnostic agents) were chosen according to human consumption and occurrence in the aquatic environment (sewage plant effluents, rivers and groundwater) to investigate their behavior during photocatalytic oxidation. From data compilation in the literature, the active metabolite clofibric acid of some lipid lowering agents, the anti-epileptic drug carbamazepine and the X-ray contrast media iomeprol were selected. The degradation of the persistent pollutant was monitored by HPLC/DAD/FLD. The study also focuses on the identification and quantification of possible degradation products by HPLC/DAD/FLD and HPLC/MS/MS. The degradation process was also monitored by determination of sum parameters and inorganic ions. Various aromatic and aliphatic degradation products have been identified and quantified. From analytical data, a possible degradation scheme for carbamazepine was proposed. Kinetic studies showed that the TiO 2 photocatalyst P25 was more active in clofibric acid degradation than Hombikat UV100. For photocatalytic degradation of iomeprol Hombikat UV100 was more suitable than P25. In general the presence of NOM and carbamazepine retarded the photocatalysis of clofibric acid. Radiation attenuation, competition for active sites and surface deactivation of the catalyst by adsorption are the reason for that. The results of this work proof that photocatalysis is a promising technology to reduce persistent substances even if they are present in low concentrations or in a complex matrix.

Cross-flow microfiltration with periodical back-washing for photocatalytic degradation of pharmaceutical and diagnostic residues–evaluation of the long-term stability of the photocatalytic activity of TiO2

The combination of semiconductor photocatalysis with cross-flow microfiltration accompanied by periodical back-washing was investigated in a pilot plant. The investigation included the testing of membrane materials because the membrane must resist the abrasion and the periodical back-washing. Another objective of this investigation was to assess the potential of two different TiO(2) materials (Hombikat UV100 and P25) for continuous photocatalytic degradation of persistent organic pollutants. The study focused on the long-term stability of the photocatalytic activity of TiO(2) during its continuous application. The combination of photocatalysis and cross-flow microfiltration allowed the separation and reuse of TiO(2) after the photocatalytic degradation of clofibric acid, carbamazepine and iomeprol. The investigations showed that the photocatalytic activity of P25 and Hombikat UV100 was constant during continuous usage over several days. This study indicates the high potential of the combination of heterogeneous photocatalytic oxidation processes with cross-flow microfiltration accompanied by periodical back-washing of the membrane. Thus environmentally relevant pharmaceuticals and X-ray contrast media can be transformed and mineralized in a continuous water treatment process.

Kinetic study of photocatalytic degradation of carbamazepine, clofibric acid, iomeprol and iopromide assisted by different TiO 2 materials—determination of intermediates and reaction pathways

The light-induced degradation of clofibric acid, carbamazepine, iomeprol and iopromide under simulated solar irradiation has been investigated in aqueous solutions suspended with different TiO 2 materials (P25 and Hombikat UV100). Kinetic studies showed that P25 had a better photocatalytic activity for clofibric acid and carbamazepine than Hombikat UV100. For photocatalytic degradation of iomeprol Hombikat UV100 was more suitable than P25. The results can be explained by the higher adsorption capacity of Hombikat UV100 for iomeprol. The study also focuses on the identification and quantification of possible degradation products. The degradation process was monitored by determination of sum parameters and inorganic ions. In case of clofibric acid various aromatic and aliphatic degradation products have been identified and quantified. A possible multi-step degradation scheme for clofibric acid is proposed. This study proves the high potential of the photocatalytic oxidation process to transform and mineralize environmentally relevant pharmaceuticals and contrast media in water.

Different distribution and regulation of chloride channels in mammalian and amphibian skeletal muscles

Aqueous solutions containing the metabolite clofibric acid (2-(4-chlorophenoxy)-2-methylpropionic acid) up to close to saturation in the pH range 2.0–12.0 have been degraded by anodic oxidation with Pt and boron-doped diamond (BDD) as anodes. The use of BDD leads to total mineralization in all media due to the efficient production of oxidant hydroxyl radical (OH). This procedure is then viable for the treatment of wastewaters containing this compound. The effect of pH, apparent current density, temperature and metabolite concentration on the degradation rate, consumed specific charge and mineralization current efficiency has been investigated. Comparative treatment with Pt yields poor decontamination with complete release of stable chloride ion. When BDD is used, this ion is oxidized to Cl2. Clofibric acid is more rapidly destroyed on Pt than on BDD, indicating that it is more strongly adsorbed on the Pt surface enhancing its reaction with OH. Its decay kinetics always follows a pseudo-first-order reaction and the rate constant for each anode increases with increasing apparent current density, being practically independent of pH and metabolite concentration. Aromatic products such as 4-chlorophenol, 4-chlorocatechol, 4-chlororesorcinol, hydroquinone, p-benzoquinone and 1,2,4-benzenetriol are detected by gas chromatography–mass spectrometry (GC–MS) and reversed-phase chromatography. Tartronic, maleic, fumaric, formic, 2-hydroxyisobutyric, pyruvic and oxalic acids are identified as generated carboxylic acids by ion-exclusion chromatography. These acids remain stable in solution using Pt, but they are completely converted into CO2 with BDD. A reaction pathway for clofibric acid degradation involving all these intermediates is proposed.