Mineralization Of Paracetamol Research Articles

Al/Cu-PILC as a Photo-Fenton Catalyst: Paracetamol Mineralization.

Pillared clays have shown to effectively catalyze the photo-Fenton process without the necessity of acidic conditions, which is a very attractive feature from the perspective of environmentally friendly processes, especially when high natural abundance of chemical elements are incorporated. In this work, the catalytic activity of Al/Cu interlayered pillared clays for the degradation and mineralization of paracetamol through a photo-Fenton-like process was investigated. Al/Cu-pillared clays were prepared by adding ane Al/Cu pillaring solution to a bentonite suspension. X-ray diffraction (XRD) confirmed the enlargement of the interlayer space of the clay provoked by the pillaring process and Al and Cu species in the prepared samples were verified by atomic absorption spectroscopy (AAS). The specific surface area of pure bentonite was 2-fold increased after the Al/Cu pillaring process. A synthetic paracetamol solution with an initial concentration of 100 ppm was prepared for the assessment of the activity of the prepared materials. Different catalyst concentrations were tested (0.2, 0.5, 0.75, and 1 g L–1) and the complete removal of paracetamol was achieved in all cases, but the highest mineralization rate (69.8 mg total organic carbon (TOC) gcat–1 h–1) corresponds to the catalyst loading of 0.5 g L–1. An ultraviolet-C (UVC) light source was employed, and no adjustment of the pH to acidic conditions was needed to achieve these results. Liquid chromatography coupled to mass spectroscopy (LC-MS) was employed to identify the reaction intermediates of paracetamol degradation. A proposed pathway for the oxidation of paracetamol molecule is presented. The effect of Cu content in the pillared clay and the stability and reusability of the catalyst were also assessed. The kinetic constants of paracetamol removal were 0.2318 and 0.0698 min–1, under photo-Fenton and UV + H2O2 processes, respectively.

Degradation of pharmaceutical drug paracetamol via UV irradiation using Fe-TiO2 composite photocatalyst: statistical analysis and parametric optimization.

In the present investigation, a novel Fe-TiO2 composite was fabricated by mixing fly ash (FA), foundry sand (FS), and bentonite clay for the degradation of paracetamol (PCM). This composite acts as a surface for immobilizing the TiO2 catalyst (using the dip-coating method) besides facilitating the leaching of iron (FA and FS) in acidic conditions. Leached iron (in the form of Fe(II), Fe(III), and total iron) promotes the photo-Fenton (with the addition of H2O2 in the system) while the surface-active TiO2 layer leads to photocatalysis, thus leading to in situ dual process combining photocatalysis and photo-Fenton in one system. This dual process led to a synergy of 75% in comparison to the photocatalysis and photo-Fenton process owing to the large production of •OH. Various parameters such as H2O2 dose (525 mg l-1), number of beads (80), degradation time (215 min), and volume (200 ml) were optimized, and 96.6% of reduction in PCM was observed. Durability study of catalyst showed a minor reduction in the activity of the catalyst after 30 cycles. The TiO2 catalyst was still intact as a film, and iron leaching was also occurring from the beads even after recycling, thus confirming their long-term durability in terms of dual effect. The stability and durability of the composite were confirmed by characteristic analysis such as SEM/EDS. Mineralization of PCM was concluded through the estimation of degradation by-products using GC-MS analysis followed by estimation of nitrate and nitrite ions.

Enhanced degradation of paracetamol by combining UV with electrogenerated hydrogen peroxide and ozone

The in-situ production of highly oxidizing species represents a sustainable approach for the treatment of unregulated emerging contaminants. In this article, we investigate the UV induced degradation and mineralization of paracetamol that represents one of the most frequently prescribed and sold drugs worldwide. In particular, this work compares two advanced oxidation processes based on photolysis of electrogenerated hydrogen peroxide (H2O2), and ozone (O3). The H2O2 electrosynthesis has been performed via oxygen reduction on gas diffusion electrodes (GDE). To maximize the efficiency of the treatments, the effect of the main operative parameters such as reagent concentration, pH, current density and UV irradiance has been discussed. The results show that, due to the synergistic effect, paracetamol undergoes rapid degradation and extensive mineralization. The comparison of the cost-effectiveness of the treatments, in terms of energy consumption, is also provided.

Paracetamol mineralization by Photo Fenton process catalyzed by a Cu/Fe-PILC under circumneutral pH conditions

This study presents an iron-pillared clay (Fe-PILC) ion-exchanged with copper (Cu/Fe-PILC), as an efficient catalyst to conduct the mineralization of paracetamol through photo-Fenton process at near to neutral pH without precipitation of Fe complexes and without adding any chemicals to modify the initial pH. The specific surface area of the catalyst was of 110 m2 g−1 and with the following phases FeO, Fe3O4, Cu2O, CuO determined by XPS analyses. Around 80% of mineralization was reached either by conducting the process at acidic and circumneutral pH conditions, and the efficiency was not significantly higher at pH = 2.7. The intermediate reaction products generated at both pH conditions essayed and detected by LC–MS were hydroquinone, acetamide and oxamic acid. Catalyst Cu/Fe-PILC showed an iron leaching of about 3% after reaction while the reusability of the catalyst involved a decrease in mineralization of only 3% under circumneutral conditions. The final TOC of about 20% can be ascribed to the presence of acetamide that was found to be the most reluctant towards oxidation.

A Review on Chemical Advanced Oxidation Processes for Pharmaceuticals with Paracetamol as a Model Compound. Reaction Conditions, Intermediates and Total Mechanism

Background: In recent years, there has been a growing interest in the environmental relevance of the presence of several pharmaceutical compounds and their metabolites in water. To avoid further accumulation of these compounds and their metabolites in the aquatic environment, several research groups are investigating chemical and photochemical methods that could be applied in their destruction and subsequent removal from natural and wastewater. Objective & Method: Different chemical advanced oxidation processes are being developed to destroy organic pollutants in water. Most of these methods are based on the production of HO• radicals that are known to be highly reactive and strong oxidizing agents. In aqueous chemical processes, these radicals can be generated using a variety of reagents and under different reaction conditions such as O3, H2O2/UV, TiO2/UV, O3/UV, H2O2/Fe2+, H2O2/Fe2+/UV and O3/Fe2+/Cu2+/UV. This review is a survey on recent advances in the application of different chemical advanced oxidation processes to mineralize pharmaceuticals. Paracetamol was selected as a model compound since its structure is the main component or metabolite of several anesthetic and analgesic compounds. The degradation of paracetamol by different advanced oxidation methods has been investigated by a combination of techniques (TOC, UV-Vis, IR, HPLC and GC-MS) in order to determine the optimal reaction conditions, kinetics, intermediate and product compounds generated. Conclusion: Understanding the basic concepts about reaction conditions, intermediates and mechanistic details on mineralization of paracetamol will be quite useful for future applications of several techniques in the removal of this and other structurally related pharmaceutical and aromatic compounds from water. Keywords: Paracetamol, ozonolysis, Fenton, photo-Fenton, TiO2-photocatalysis, pharmaceutical compounds, aromatic compounds.

Facile Preparation of Porous Carbon Cathode to Eliminate Paracetamol in Aqueous Medium Using Electro-Fenton System

Porous carbon cathode (PCF) was fabricated by thermal treatment at high temperature under a nitrogen gas flow mixed with 1% of oxygen. Scanning electron microscopy results revealed a homogenous porosity covered the carbon fibres. This property improved significantly the hydrophilicity that supported the oxygen reduction reaction (ORR) in electro-Fenton process as confirmed by contact angle measurements. In addition, an increase of 700 times of the surface area is observed after the thermal treatment. The crystalline average size of the new material was also ameliorated during thermal treatment as observed by X-ray diffraction pattern (XRD) due to the selective etching of amorphous carbon. Porous cathode exhibited also better electrochemical performances than raw carbon felt cathode as proved by cyclic voltammograms (CVs) because of the higher electroactive surface area. According to the Randles-Sevcik formula, the electroactive surface area of PCF was 10 times higher than raw CF. The concentration of H2O2 on PCF and raw CF was 24.6, 7.9mgL⿿1 respectively after 80min. The porous cathode was applied for removal of paracetamol (PCM) in acidic aqueous medium using an electro-Fenton process. Mineralization of PCM was followed by total organic carbon (TOC) measurements and an improvement of 31% was observed compared to the non-modified cathode after 2h of electrolysis. The porous carbon cathode kept its stability after 10 cycles.

Supporting of pristine TiO2 with noble metals to enhance the oxidation and mineralization of paracetamol by sonolysis and sonophotolysis

Pharmaceutical residues in fresh water bodies are of significant environmental concern due to their undesirable effects on aquatic organisms at very low concentrations. The present study is about the elimination and overall degradation of a common anti-inflammatory pharmaceutical-paracetamol (PCT) in water by catalytic oxidation using high-frequency ultrasound, UV-irradiation (254nm) and both. The catalysts were synthesized sonolytically by the reduction of Pd and Au to the zero-valent state followed by immobilization of the nanoparticles on the surface of commercial TiO2 (P-25) to improve the activity of the semiconductor under ultrasonic and UV irradiation. It was found that sonolytic oxidation of PCT during catalysis with Pd–TiO2 and Pd/Au–TiO2 was very effective owing to the significantly smaller size of these particles (than that of Au–TiO2), which promoted the formation and collapse of cavitation bubbles on their surface and the incidence of solute contact with the active sites. The addition of persulfate further enhanced the rate of PCT decay, signifying the role of ultrasound in activating the reagent and that of radical-initiated oxidation reactions in the decomposition of the parent compound. The activity of P-25 was low and almost equal under sonolysis and photolysis, but considerably higher under sono-photolysis, where the unfavorable properties of the semiconductor were minimized via combined effects of the two processes. Hybridization also induced a considerable synergy in carbon-mineralization, which was relatively low with single processes. The results were attributed to minimization of electron-hole pair recombination, surface corrosion and competition for photons and radical species. Au-supported particles exhibited higher activity in the presence of UV-irradiation than ultrasound, which was attributed to the unique activity of gold in the UV–vis region. Finally, Pd–TiO2 was found to be the most stable nanocomposite in terms of the ease of recovery and the efficiency of reuse.

Mineralization of paracetamol in aqueous solution with advanced oxidation processes

Paracetamol is a common analgesic drug widely used in all regions of the world more than hundred tonnes per year and it poses a great problem for the aquatic environment. Its phenolic intermediates are classified as persistent organic pollutants and toxic for the environment as well as human beings. In the present study, the irradiation of aqueous solutions of paracetamol with 60Co gamma-rays was examined on a laboratory scale and its degradation path was suggested with detected radiolysis products. The synergic effect of ozone on gamma-irradiation was investigated by preliminary ozonation before irradiation which reduced the irradiation dose from 5 to 3 kGy to completely remove paracetamol and its toxic intermediate hydroquinone from 6 to 4 kGy as well as increasing the radiation chemical yield (Gi values 1.36 and 1.66 in the absence and presence of ozone, respectively). The observed amount of formed hydroquinone was also decreased in the presence of ozone. There is a decrease in pH from 6.4 to 5.2 and dissolved oxygen consumed, which is up to 0.8 mg l−1, to form some peroxyl radicals used for oxidation. Analytical measurements were carried out with gas chromatography/mass spectrometry and ion chromatography (IC) both qualitatively and quantitatively. Amounts of paracetamol and hydroquinone were measured with gas chromatography after trimethylsilane derivatization. Small aliphatic acids, such as acetic acid, formic acid and oxalic acid, were measured quantitatively with IC as well as inorganic ions (nitrite and nitrate) in which their yields increase with irradiation.

Heterogeneous Fenton oxidation of paracetamol using iron oxide (nano)particles

100mgL−1 paracetamol aqueous solutions were treated by heterogeneous Fenton oxidation at acidic pH (2.6). Three types of iron oxides – nano- and submicro-structured magnetite, nanostructured maghemite – were tested as catalysts for that purpose. For each system, the paracetamol conversion and mineralization yield (Total Organic Carbon removal) were evaluated, as well as the catalyst stability upon recycling.The influence of reaction parameters such as temperature, iron amount, and hydrogen peroxide dosage was also investigated. Paracetamol mineralization was improved by high temperature and low oxidant dosage due to radical scavenging effects. In best conditions (two times the stoichiometric amount of H2O2, a temperature of 60°C, a catalyst concentration of 6gL−1), paracetamol was fully degraded after 5h, but total mineralization was not yet achieved: TOC removal reached about 50% when magnetite powders were used as catalysts. All iron oxides exhibited low iron leaching (<1%) and stable catalytic activity upon first recycling.

Degradation of paracetamol by pure bacterial cultures and their microbial consortium

Three bacterial strains utilizing paracetamol as the sole carbon, nitrogen, and energy source were isolated from a paracetamol-degrading aerobic aggregate, and assigned to species of the genera Stenotrophomonas and Pseudomonas. The Stenotrophomonas species have not included any known paracetamol degraders until now. In batch cultures, the organisms f1, f2, and fg-2 could perform complete degradation of paracetamol at concentrations of 400, 2,500, and 2,000 mg/L or below, respectively. A combination of three microbial strains resulted in significantly improved degradation and mineralization of paracetamol. The co-culture was able to use paracetamol up to concentrations of 4,000 mg/L, and mineralized 87.1 % of the added paracetamol at the initial of 2,000 mg/L. Two key metabolites of the biodegradation pathway of paracetamol, 4-aminophenol, and hydroquinone were detected. Paracetamol was degraded predominantly via 4-aminophenol to hydroquinone with subsequent ring fission, suggesting new pathways for paracetamol-degrading bacteria. The degradation of paracetamol could thus be performed by the single isolates, but is stimulated by a synergistic interaction of the three-member consortium, suggesting a possible complementary interaction among the various isolates. The exact roles of each of the strains in the consortium need to be further elucidated.

Mineralization of paracetamol by ozonation catalyzed with Fe2+, Cu2+ and UVA light

Acid solutions containing up to 1gl−1 of the drug paracetamol have been treated with ozone alone and ozonation catalyzed with Fe2+, Cu2+ and/or UVA light at 25.0°C. Direct ozonation yields poor degradation due to the high stability of final carboxylic acids formed, whereas more than 83% of mineralization is attained with the catalyzed methods. Under UVA irradiation, organics can be efficiently destroyed by the combined action of generated H2O2 and UVA light. In the presence of Fe2+ and UVA light, the process is accelerated due to the production of oxidant hydroxyl radical (OH) and the photodecomposition of Fe3+ complexes. The highest oxidizing power is achieved by combining Fe2+, Cu2+ and UVA light, because complexes of final acids with Cu2+ are more quickly degraded than those competitively formed with Fe3+. For all catalyzed methods, the initial mineralization rate is enhanced and the percent of degradation generally drops with increasing drug concentration. The paracetamol decay always follows a pseudo-first-order reaction with slightly higher rate constant for catalyzed systems than direct ozonation. Aromatic products such as hydroquinone, p-benzoquinone and 2-hydroxy-4-(N-acetyl)aminophenol are identified by gas chromatography–mass spectrometry (GC–MS) and reversed-phase chromatography. Acetamide is generated when hydroquinone is produced. These products are degraded to oxalic and oxamic acids as ultimate carboxylic acids, as detected by GC–MS and ion-exclusion chromatography. Oxalic acid is generated via glycolic, glyoxylic, tartronic, ketomalonic and maleic acids. While Fe3+-oxalato complexes are photolyzed by UVA light, Cu2+-oxalato, Fe3+-oxamato and Cu2+-oxamato complexes are oxidized with OH. NH4+ and NO3− ions are produced during mineralization.

Mineralization of paracetamol in aqueous medium by anodic oxidation with a boron-doped diamond electrode

The degradation of 100 ml of solutions with paracetamol ( N-(4-hydroxyphenyl)acetamide) up to 1 g l −1 in the pH range 2.0–12.0 has been studied by anodic oxidation in a cell with a boron-doped diamond (BDD) anode and a graphite cathode, both of 3-cm 2 area, by applying a current of 100, 300 and 450 mA between 25 and 45 °C. Complete mineralization is always achieved due to the great concentration of hydroxyl radical ( OH) generated at the BDD surface, with release of NH 4 + and NO 3 - ions. The mineralization rate is pH-independent, increases with increasing applied current and temperature, but decreases when drug concentration raises from 315 mg l −1. Reversed-phase chromatography revealed a similar complex paracetamol decay in acid and alkaline media. Ion-exclusion chromatography allowed the detection of oxalic and oxamic acids as ultimate carboxylic acids. When the same solutions have been comparatively treated with a Pt anode, a quite poor mineralization is found because of the production of much lower OH concentration. Under these conditions, the degradation rate is enhanced in alkaline medium and polymerization of intermediates is favored in concentrated solutions. Paracetamol can be completely destroyed with Pt and its kinetics follows a pseudo-first-order reaction with a constant rate independent of pH.

Paracetamol Mineralization by Advanced Electrochemical Oxidation Processes for Wastewater Treatment

Environmental Context.Even after passing through water treatment plants, discarded pharmaceuticals have been linked with poisoning aquatic life. A simple and reliable method for treating household wastewater would alleviate this issue. Using the common pain reliever paracetamol as a model, the simple combination of dissolved iron and copper with ultraviolet light is shown to fully decompose (‘mineralize’) this drug into simple inorganic components, which represents an improvement over current treatments with ozone or peroxides, that achieve only partial mineralization. Abstract.Paracetamol solutions at pH 3.0 have been efficiently mineralized by environmentally clean electrochemical methods such as electro-Fenton and photoelectro-Fenton processes using a cell with a Pt anode and an O2-diffusion cathode for H2O2 electrogeneration. This species reacts with added Fe2+ giving hydroxyl radical as main oxidant. Photoelectro-Fenton with Fe2+, Cu2+, and UVA light as catalysts leads to complete mineralization due to the removal of the final carboxylic acids (oxalic and oxamic). When catalysts are used separately, both acids or part of them remain in solution, giving a partial (&gt; 65%) mineralization.