Explore the vast range of titles available.

Non-steroidal anti-inflammatory drugs (NSAIDs) act as antipyretics, analgesics and anti-inflammatories. Among them, diclofenac and ibuprofen are the most consumed drugs worldwide. During the COVID-19 pandemic, some NSAIDs, such as dipyrone and paracetamol, have been used to alleviate the symptoms of the disease, causing an increase in the concentrations of these drugs in water. However, due to the low concentration of these compounds in drinking water and groundwater, few studies have been carried out on the subject, especially in Brazil. Thus, this study aimed to evaluate the contamination of the surface water, groundwater, and water treated with diclofenac, dipyrone, ibuprofen, and paracetamol at 3 cities (Orocó, Santa Maria da Boa Vista and Petrolândia) in the Brazilian semiarid region, in addition to analyzing the removal of these drugs by conventional water treatment (coagulation, flocculation, sedimentation, filtration and disinfection) in stations to each city. All drugs analyzed were detected in surface and treated waters. In groundwater, only dipyrone was not found. Dipyrone was seen in surface water with a maximum concentration of 1858.02 μg.L−1, followed by ibuprofen (785.28 μg.L−1), diclofenac (759.06 μg.L−1) and paracetamol (533.64 μg.L−1). The high concentrations derive from the increased consumption of these substances during the COVID-19 pandemic. During the conventional water treatment, the maximum removal of diclofenac, dipyrone, ibuprofen and paracetamol was 22.42%; 3.00%; 32.74%; and 1.58%, respectively, which confirms the inefficiency of this treatment in removing drugs. The variation in removal rate of the analyzed drugs is due to the difference in the hydrophobicity of the compounds.

The release without proper treatment of pharmaceutical contaminants into the environment, such as the antiretrovirals lamivudine and zidovudine, can lead to serious changes in ecosystems, causing different types of environmental problems. In this scenario, it is necessary to study and apply treatments capable of degrading these types of contaminants, such as the application of advanced oxidation processes (AOP). In this work, the heterogeneous photocatalysis AOP was applied for the degradation of a mixture of the drugs lamivudine and zidovudine (15 mg‧L−1 each) in aqueous medium (AM) and synthetic effluent (SE). For this, a benchtop photolytic reactor equipped with UV-C, UV-A and sunlight irradiations was used. Assays for heterogeneous photocatalysis were carried out with brass plates calcined at 500 °C and coated with 2 types of TiO2 ((A) and (B)), with the efficiency of the treatment being evaluated via ultraviolet/visible spectrophotometry. The optimized operational conditions were obtained using a coating ratio of 0.6 mg.cm−2, and under UV-C irradiation for the two matrices, reaching a respective degradation of 70.83% and 60.40% in AM and 37.81% and 37.29% in SE after 300 min. The kinetic evaluation showed a good fit to the pseudo-first order model with (R2) ≥ 0.96. Toxicity tests involving the application of lettuce, carrot and tomato seeds were carried out. These showed an inhibition of the growth of the three seeds for the solutions submitted to the AOP, for the AM and the SE. Such behavior was not verified for the initial solutions, indicating that the intermediates formed during the AOP can be more toxic even after application of the treatment.

The solution mixture of the non-steroidal anti-inflammatory drugs ketoprofen, meloxicam and tenoxicam was degraded through systems, composed of different photocatalysts based on TiO2 (Fe and Cu) and the hydrogen peroxide oxidant. The monitoring was performed by UV-Vis spectroscopy. Under sunlight radiation, a reduction in peaks was observed with the use of impregnated photocatalysts. After 60 min, the sun/H2O2/Fe-TiO2 system reached degradations of 46.5% and 93.2% at 260 and 367 nm, respectively, and was selected for further studies. The degradation kinetic reached 92 and 96% of degradation after 180 min, for the λ of 260 and 367 nm, respectively. The kinetic curve could be represented by the empirical model proposed by Nichela and co-authors, indicating that besides the heterogeneous photocatalysis that occurs at the surface of the TiO2 there is also the joint effect of the photo-Fenton process. After the treatment, there was no toxicity to cress and lettuce seeds. However, a sensitivity of the thyme seeds to the compounds formed during the treatment was verified. After the fifth treatment cycle, the supported photocatalyst showed degradation higher than 82%. These results indicate that this system is suitable for the treatment of effluents containing pharmaceutical compounds.

Abstract Advanced oxidation processes (AOP) are known for their efficiency in degrading organic pollutants. In this way, there is a continuous interest in promoting improvements in operating conditions, which can be done through the combination with homogeneous and electrochemical processes. In this work, the degradation of the mixture of dyes applied in the sanitizer industry, acid yellow 36 (AY36) and acid blue 80 (AB80), was evaluated against photo-electrochemical processes, associating individually and combined way UV-A and UV-C radiations. It was verified that the use of UV-C radiation was more efficient, promoting the complete degradation of the chromophore groups and reducing the aromatic groups by 76% when making use of the photo-electro-Fenton system (PEF/FeCl3). The experimental data followed a nonlinear kinetics suitable for pseudo-first-order models. Multilayer perceptron (MLP) artificial neural networks (6–6-3) using the Statistica 8.0 software allowed the modeling of the treatments applied in this work and showed a good prediction of data for the dye mixture. The results of this study show that the use of photo-electrochemical processes is an effective way to treat dyes used in sanitizing industries.

During the research, the structure of bean pod residues (BPRs) was evaluated as a support medium to fix magnetite (Fe3O4) and pyrite (FeS2) particles, forming composites capable of acting as catalysts for Fenton reactions. The respective iron particles were synthesized through coprecipitation and hydrothermal methods that allowed the synthesis of these particles and led to the formation of BPR/Fe3O4 and BPR/FeS2 composites. The success of the methodologies used was confirmed from the characterization analyses using the FTIR, XRD, SEM–EDS, and TG techniques. The high catalytic potential of BPR/Fe3O4 and BPR/FeS2 was verified after use for the degradation of the aqueous mixture of four textile dyes using the Fenton (36.20%/53.33%), photo-Fenton (94.69%/90.86%), sono-Fenton (73.70%/58.98%), and sono-photo-Fenton (74.01%/62.22%). The BPR/Fe3O4 showed greater catalytic activity and, therefore, its reuse capacity was evaluated through the photo-Fenton system with solar radiation. It was evidenced that the material is stable, having a high potential for reuse. Thus, it can be stated that a new applicability was granted to bean pod waste, appearing as an alternative to solve solid waste problems. Linked to this, the proposed immobilization of iron particles, which are commonly placed in suspension for catalysis of Fenton reactions, helped to fill in yet another gap, which still exists in the literature on AOP treatments.

Oxytetracycline is one of the antibiotics most frequently used in the Shrimp Industry during the control of bacterial diseases. These emerging pollutants, which appear in low concentrations, are persistent and alternative treatments and are required for their elimination. The degradation of oxytetracycline was evaluated in an aqueous solution by applying homogeneous (UV/H2O2 and photo-Fenton) and heterogeneous (UV/TiO2/H2O2) advanced oxidative processes (AOPs). The studies were carried out using a bench reactor with short-wave ultraviolet lamps (UV-C). We quantified the extent to which the degradation of the drug had been efficient by employing highly efficient liquid chromatography (HPLC) and a PDA detector with a wavelength of 354 nm and a C18 column. The best results were obtained when applying the UV/H2O2 treatment, which attained a degradation of 97% under the initial conditions of a dose of 8 µL of H2O2 and 120 min of radiation. The pseudo-first order kinetic model proposed by Chan and Chu showed that the experimental results had an adequate fit, with values greater than R2 ≥ 0.95. Toxicity tests were applied to verify the effect of AOPs employed, when the drug was present in low concentrations. The test results demonstrated a decrease in the root growth of the species Lactuca sativa and Daucus carota.

The presence of pharmaceutical contaminants in nature is an environmental problem generating increasing concerns. Due to this, it is necessary to evaluate treatments capable of degrading these contaminants, such as the advanced oxidation processes (AOPs). In this work, the photoperoxidation and photo-Fenton AOP were applied to degrade a mixture of lamivudine and zidovudine in an aqueous medium and synthetic effluent (SE). To this end, a bench reactor (UV-C; UV-A and sunlight irradiations) was built. The AOP treatments efficiency was evaluated by ultraviolet/visible spectrophotometry. The tests Involved the application of the irradiations individually and combined. The best operational conditions were [H2O2] of 600 mg L-1 and [Fe] of 0.5 mg L-1, for both matrices, with degradations of 90.53% and89.32% for the photoperoxidation and photo-Fenton processes in aqueous media and 88.69% and85.79% in SE. Kinetic studies showed a good fit for two pseudo-first-order models with R2 > 0.93. Toxicity tests involving the application of lettuce, carrot, and tomato seeds showed an inhibition for the three seeds when submitted to solutions after treatment, for both matrices, this fact is corroborated by the HPLC analysis, in which the formation of small peaks was verified, suggestive of the formation of byproducts. Thus, it can be affirmed that both photo-Fenton and photoperoxidation processes efficiently degrade the drug mixture when applying UV-C radiation.

The non-steroidal anti-inflammatory pharmaceuticals ketoprofen, meloxicam, and tenoxicam were degraded by photo-assisted peroxidation (hv/H2O2) and photo-Fenton processes under simulated solar radiation (sunlight) and UV-C. Preliminary studies showed that the processes under UV-C and sun-photo-Fenton radiation showed similar degradation results. The sun-photo-Fenton was less sensitive to the concentration variation of the H2O2 oxidant. Given that, in general, the highest percentages of degradation were achieved using the sun-photo-Fenton system and that this radiation resembles solar radiation, this process was selected for further studies. From the results of a factorial design 23, in duplicate, the highest degradation condition within the studied levels was 400 mg L−1 of [H2O2], 1.75 mg L−1 of [Fe], and pH at 3–4 range. The kinetic degradation curve, monitored by the chemical oxygen demand (COD), could be represented by the pseudo-first-order model, and after 120 min the COD concentrations reached values below 2% of the initial demand. Degradation products from the three drugs were identified by high-performance liquid chromatography with coupled mass spectrometry (UCLAE-EM) and verified the toxicity of Escherichia coli and Salmonella enteritidis bacteria and of lettuce seeds (Lettuce Veneranda), indicating the formation of compounds that have lower molecular mass and can be more easily degraded, using this process as one of the stages of a system of treatment.

This work investigates the efficiency of LED and UV-C photo-reactors for paracetamol degradation using advanced oxidative processes. Among the evaluated processes, photo-Fenton was the most efficient for both radiations. Degradations greater than 81% (λ 197 nm) and 91% (λ 243 nm) were obtained in the kinetic study. These degradations were also observed by means of the reduction in the peaks in both spectral scanning and high-performance liquid chromatography analysis. The good fit of the Chan and Chu kinetic model shows that the degradation reaction has pseudo-first order behavior. Toxicity tests did not indicate the inhibition of growth of Lactuca sativa seeds and Escherichia coli bacterium. However, the growth of strains of the Salmonella enteritidis bacterium was inhibited in all the samples, demonstrating that only this bacterium was sensitive to solutions. The proposed empirical models obtained from the 24 factorial designs were able to predict paracetamol degradation. These models could, at the same levels assessed, be used to predict the percentage of degradation in studies using other organic compounds. The LED and UV-C photo-reactors were, when employing the photo-Fenton process, able to degrade paracetamol, thus highlighting the efficiency of LED radiation when its power (three times smaller) is compared to that of UV-C radiation.

Abstract In this work, we investigated the degradation of the mixture of acid yellow 36 and acid blue 80 via photoperoxidation (PP/UV-C) and via electrochemical oxidation (EAOP). After optimization, the best results were obtained using [H2O2] = 80 mg‧L−1 for PP/UV-C and concentrations of 0.05 mol∙L−1 of the electrolytes (Na2SO4 and KCl) for EAOP/UV-C. For PP/UV-C, complete degradation of the monitored groups was obtained for all 3 λ. For the electrochemical systems, the higher degradation efficiency was achieved by using UV-C radiation associated with the electrochemical absorption process (EAOP/UV-C), reaching 75% for 267 nm and 100% for the other λ from 180 min. A kinetic monitoring by HPLC analytical technique was performed in order to visualize the possible reaction intermediates, as well as the consumption of H2O2 and the production of chlorine compounds as oxidizing agents of the applied processes. The toxicity evaluation against Nasturtium officinale, Daucus carota subsp. Sativus, and Thymus vulgar seeds and for Escherichia coli showed the presence of intermediate species of the dyes due to a certain degree of post-treatment toxicity. It was concluded that the use of the PP/UV-C and EAOP processes was efficient for the degradation of the dyes studied, although the system must be further improved to achieve better mineralization.