RESUMEN
Post-surgical adhesion is a medical challenge, especially following abdominal and pelvic surgeries. This refers to the formation of fibrotic scars that form from connective tissue in the gynecological tract or abdominal cavity. Dysfunctional adipose tissue (AT) by surgical injuries and hypoxia increases the risk of post-surgical adhesion through different molecular mechanisms. Damage-associated molecular patterns (DAMPs) and Hypoxia-induced factor 1 alpha (HIF-1α) produced during surgery trauma and hypoxia induce AT dysfunction to promote inflammation, oxidative stress, metabolic alterations, and profibrotic pathways, which contribute to post-surgical adhesions. HIF-1α and DAMPs can be considered therapeutic targets to prevent AT dysfunction and diminish the formation of adhesions in obese patients undergoing abdominal or pelvic surgeries.
RESUMEN
Rainfed regions have inconsistent spatial and temporal rainfall. So, these regions could face water deficiency during critical stages of crop growth. In this regard, multi-environment trials could play a key role in introducing stable genotypes with good performance across several rainfed regions. Grass pea, as a potential forage crop, is a resilient plant that could grow in unsuitable circumstances. In this study, agro-morphological attributes of 16 grass pea genotypes were examined in four semi-warm rain-fed regions during the years 2018-2021. The MLM analysis of variance showed a significant genotype-by-environment interaction (GEI) for dry yield, seed yield, days to maturity, days to flowering, and plant height of grass pea. The PLS (partial least squares) regression revealed that rainfall in the grass pea establishment stage (October and November) is meaningful. For grass pea cultivation, monthly rainfall during plant growth is important, especially in May, with an aim for seed yield. Regarding dry yield, G5, G10, G11, G12, G13, and G15 were selected as good performers and stable genotypes using DY × WAASB biplots, while SY × WAASB biplot manifested G2, G3, G12, and G13 as superior genotypes with stable seed yield. Considering equal weights for yield as well as the WAASB stability index (50/50), G13 was selected as the best one. Among test environments, E2 and E11 played a prominent role in distinguishing the above genotypes from other ones. In this study, MTSI (multi-trait stability index) analysis was applied to select a stable genotype, considering all measured agro-morphological traits simultaneously. Henceforth, the G5 and G15 grass pea genotypes were discerningly chosen due to their commendable performance in the WAASBY plot. In this context, G13 did not emerge as the winner based on MTSI; however, it exhibited an MTSI value in close proximity to the outer boundary of the circle. Consequently, upon comprehensive consideration of all traits, it is deduced that G5, G13, and G15 can be appraised as promising superior genotypes with stability across diverse environmental conditions.
Asunto(s)
Interacción Gen-Ambiente , Genotipo , Lluvia , Pisum sativum/genética , Pisum sativum/crecimiento & desarrollo , Pisum sativum/fisiología , Semillas/genética , Semillas/crecimiento & desarrolloRESUMEN
In this study, unique BiVO4-Au-Cu2O nanosheets (NSs) are well designed and multiple charge transfer paths are consequently constructed. The X-ray photoelectron spectroscopy measurement during a light off-on-off cycle and redox capability tests of the photo-generated charge carriers confirmed the formation of Z-scheme heterojunction, which can facilitate the charge carrier separation and transfer and maintain the original strong redox potentials of the respective component in the heterojunction. The ultrathin 2D structure of the BiVO4 NSs provided sufficient surface area for the photocatalytic reaction. The local surface plasmon resonance (LSPR) effect of the electron mediator, Au NPs, enhanced the light absorption and promoted the excitation of hot electrons. The multiple charge transfer paths effectively promoted the separation and transfer of the charge carrier. The synergism of the abovementioned properties endowed the BiVO4-Au-Cu2O NSs with satisfactory photocatalytic activity in the degradation of tetracycline (Tc) with a removal rate of ≈80% within 30 min under visible light irradiation. The degradation products during the photocatalysis are confirmed by using ultra-high performance liquid chromatography-mass spectrometry and the plausible degradation pathways of Tc are consequently proposed. This work paves a strategy for developing highly efficient visible-light-driven photocatalysts with multiple charge transfer paths for removing organic contaminants in water.
RESUMEN
BACKGROUND AND AIM: The current study investigated the association between triglyceride-glucose index (TyG) and triglyceride/HDL-C indices and coronary atherosclerosis extent in diabetic and non-diabetic patients. METHODS AND RESULTS: In this case-control study, 1538 individuals were classified into two groups: diabetic and non-diabetic subjects. Each group was further grouped as follows: (1) angiography+ (2) angiography-and (3) subjects without a history of cardiovascular diseases. The TyG and TG/HDL-C indices were compared between the subgroups of the diabetic (n = 407) and non-diabetic (n = 1131) groups. In both diabetic and non-diabetic patients, there was no significant association in TG/HDL-C; and diabetic subjects, angiography+ and angiography-groups had significantly higher TyG (p < 0.05). A high TyG index was associated with a higher risk of angiography+ (OR: 1.883 (1.410-2.514)). CONCLUSIONS: The TyG index, but not the TG/HDL-C, was an independent marker for predicting the severity of coronary stenosis in non-diabetic patients.
Asunto(s)
Biomarcadores , Glucemia , HDL-Colesterol , Angiografía Coronaria , Estenosis Coronaria , Triglicéridos , Humanos , Masculino , Femenino , Persona de Mediana Edad , Triglicéridos/sangre , Estudios de Casos y Controles , Glucemia/metabolismo , Estenosis Coronaria/sangre , Estenosis Coronaria/diagnóstico por imagen , Estenosis Coronaria/diagnóstico , HDL-Colesterol/sangre , Anciano , Biomarcadores/sangre , Factores de Riesgo , Valor Predictivo de las Pruebas , Índice de Severidad de la Enfermedad , Diabetes Mellitus/sangre , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/epidemiologíaRESUMEN
This experiment aimed to evaluate the beneficial and toxic properties of synthetic zinc oxide nanoparticles (ZnO NPs) on the liver of normal and high-fat diet (HFD) fed-rats. The ZnO NPs were synthesized and, its characterizations were determined by different techniques. Effect of ZnO NP on cell viability, liver enzymes and lipid accumulation were measured in HepG2 cells after 24 h. After that, rats orally received various dosages of ZnO NPs for period of 4 weeks. Toxicity tests were done to determine the appropriate dose. In the subsequent step, the hepatoprotective effects of 5 mg/kg ZnO NPs were determined in HFD-fed rats (experiment 2). The oxidative stress, NLRP3 inflammasome, inflammatory, and apoptosis pathways were measured. Additionally, the activity of caspase 3, nitric oxide levels, antioxidant capacity, and various biochemical factors were measured. Morphological changes in the rat livers were also evaluated by hematoxylin and eosin (H & E) and Masson trichrome. Liver apoptosis rate was also approved by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Treatment of animals with 5 mg/ZnO NPs revealed potential hepatoprotective properties, while ZnO NPs at the doses of above 10 mg/kg showed toxic effects. Antioxidant enzyme gene expression and activity were significantly augmented, while apoptosis, NLRP3 inflammasome, and inflammation pathways were significantly reduced by 5 mg/kg ZnO NPs. Liver histopathological alterations were restored by 5 mg/kg ZnO NPs in HFD. Our study highlights the hepatoprotective effects of ZnO NPs against the HFD-induced liver damage, involving antioxidant, anti-inflammatory, and anti-apoptotic pathways, indicating their promising therapeutic potential.
RESUMEN
Nowadays, due to stricter pollution standards, more attention has been focused on pollutants emitted from cars. As a very dangerous pollutant, NOx has always triggered the sensitivity of the related organizations. In the process of developing and designing the engine, estimating the amount of this pollutant is of great importance to reduce future expenses. Calculating the amount of this pollutant has usually been complicated and prone to error. In the present paper, neural networks have been used to find the coefficients of correcting NOx calculation. The Zeldovich method calculated the value of NOx with 20% error. By applying the progressive neural network and correcting the equation coefficient, this value decreased. The related model has been validated with other fuel equivalence ratios. The neural network model has fitted the experimental points with a convergence ratio of 0.99 and a squared error of 0.0019. Finally, the value of NOx anticipated by the neural network has been calculated and validated according to empirical data by applying maximum genetic algorithm. The maximum point for the fuel composed of 20% hydrogen and 80% methane occurred in the equivalence ratio of 0.9; and the maximum point for the fuel composed of 40% hydrogen occurred in equivalence ratio of 0.92. The consistency of the model findings with the empirical data shows the potential of the neural network in anticipating the amount of NOx.
RESUMEN
The use of renewable energy is necessary to achieve the goals of sustainable development, and sooner or later all countries are forced to plan and make policies for the use of this equipment. Considering the growing trend of smart systems and the ability of these systems to control and use renewable resources, it is necessary to investigate how to control and optimally use these resources in smart systems. Considering the geographical conditions and significant solar energy radiation in Iran, the most suitable option for using renewable energy in residential buildings is solar energy. Among the types of solar energy used around the world, photovoltaic panels are used more due to their wide range, being cheaper than other sources of electric power from solar energy and more durable than other sources. In order to reduce widespread losses and reduce the cost of transmission and distribution, increase efficiency, the possibility of the presence of private sector investors and increase the security and stability of the power grid, distributed production of electrical energy at consumption locations using small-scale units is the most cost-effective way to use home solar panels. Also, the production of energy from wind turbines can be done in the areas where anemometer data determine it to be suitable. The combination of solar energy and wind energy can effectively reduce the need for batteries, but studies show that this combination is only economically viable when it is used on a large scale and with high powers, which requires a lot of investment. Large initial capital is one of the biggest problems of distributed production systems, so the use of artificial intelligence methods for accurate capacity determination of renewable energy production systems becomes doubly important. The economic results show that the least cost of electricity and net price cost are 0.44 $ per kWh and 15.0 million $ respectively, when the converter size was gradually changed, with a renewable fraction of 46.7%.
RESUMEN
Pharmaceutical companies worldwide are scrambling to develop new ways to combat cancer and microbiological pathogens. The goal of this research was to investigate the antibacterial, anticancer, and apoptosis effects of novel niosomal formulated Persian Gulf Sea cucumber extracts (SCEs). Sea cucumber methanolic extracts were prepared and encapsulated in niosome nanoparticles using thin-film hydration. The compound was made up of Span 60 and Tween 60 blended with cholesterol in a 3:3:4 M ratios. Characterization of niosome-encapsulated SCE evaluated by scanning electron microscopy and transmission electron microscopy. The disk diffusion method and microtiter plates were used to investigate the antimicrobial activity. The effect of niosome-encapsulated SCE on cell proliferation and apoptosis induction was studied using MTT and Annexin V, respectively. The expression of apoptosis-related genes, including Bax, Fas, Bax, Bak, and Bcl2, was studied using quantitative real-time PCR. Niosome-encapsulated SCE with a size of 80.46 ± 1.31 and an encapsulation efficiency of 79.18 ± 0.23 was formulated. At a concentration of 100 µg/ml, the greatest antimicrobial effect of the niosome-encapsulated SCE was correlated to Staphylococcus aureus, with an inhibition zone of 13.16 mm. The findings of the study revealed that all strains were unable to produce biofilms at a concentration of 100 µg/ml niosome-encapsulated SCE (p < 0.001). The survival rate of cancer cells after 72 h of exposure to niosome-encapsulated SCE was 40 ± 3.0%. Encapsulated SCE in niosomes inhibited cell progression in MCF-7 cells by increasing G0/G1 and decreasing S phase relative to G2/M phase; as a result, it activated the apoptosis signaling pathway and led to the induction of apoptosis in 69.12 ± 1.2% of tumor cells by increasing the expression of proapoptotic genes (p < 0.001). The results indicate that sea cucumber species from the Persian Gulf are a promising source of natural chemicals with antibacterial and anticancer properties, paving the path for novel marine natural products to be discovered. This is the first demonstration that niosome-encapsulated SCE contains antibacterial and anticancer chemicals that, according to their specific characteristics, boost antitumor activity.
RESUMEN
The current developments and progress in energy and environment-related areas pay special attention to the fabrication of advanced nanomaterials via green and sustainable paths to accomplish chemical circularity. The design and preparation methods of photocatalysts play a prime role in determining the structural, surface characteristics and optoelectronic properties of the final products. The solution combustion synthesis (SCS) technique is a relatively novel, cost-effective, and efficient method for the bulk production of nanostructured materials. SCS-fabricated metal oxides are of great technological importance in photocatalytic, environmental and energy applications. To date, the SCS route has been employed to produce a large variety of solid materials such as metals, sulfides, carbides, nitrides and single or complex metal oxides. This review intends to provide a holistic perspective of the different steps involved in the chemistry of SCS of advanced photocatalysts, and pursues several SCS metrics that influence their photocatalytic performances to establish a feasible approach to design advanced photocatalysts. The study highlights the fundamentals of SCS and the importance of various combustion parameters in the characteristics of the fabricated photocatalysts. Consequently, this work deals with the design of a concise framework to link the fine adjustment of SCS parameters for the development of efficient metal oxide photocatalysts for energy and environmental applications.
RESUMEN
Iron oxide nanostructured catalysts have emerged as potential candidates for efficient energy conversion and electrochemical energy storage devices. However, synthesis and design of nanomaterial plays a key role in its performance and efficiency. Herein, we describe a one-pot solution combustion synthesis (SCS) of α-Fe2O3 with glycine as a fuel, and a subsequent reduction step to produce iron-containing catalysts (i.e., Fe3O4, Fe-Fe3O4, and Fe0). The synthesized iron-based nanoparticles were investigated for methyl orange (MO) degradation through Microwave (MW) energy under continuous flow conditions. Fe-Fe3O4 showed higher MO degradation efficiency than α-Fe2O3, Fe3O4 and Fe0 at low absorbed MW power (i.e. 5-80 W). The enhanced degradation efficiency is associated to the combination of higher availability of electron density and higher heating effect under MW energy. Investigation of dielectric properties showed relative dielectric loss of Fe3O4, Fe-Fe3O4, and Fe0 as 3847, 2010, and 1952, respectively. The calculated average local temperature by the comparative analysis of MW treatment with conventional thermal (CT) treatment showed a marked thermal effect of MW-initiated MO degradation. This work highlights the potential of microwave-driven water depollution under continuous-flow processing conditions and demonstrates the positive impact that earth-abundant Fe catalyst synthesized by green SCS method can have over the treatment of wastewater.
Asunto(s)
Aguas Residuales , Contaminantes Químicos del Agua , Catálisis , Hierro , MicroondasRESUMEN
Interfacial debonding in fiber-reinforced composites is a common problem, especially in external strengthening techniques. This investigation aims to determine the load during debonding, and discusses two practical design parameters for direct shear tests, which are commonly used to assess the mechanics of debonding. In this study, three different bond-slip cohesive laws and one finite fracture mechanics approach are considered to investigate debonding in direct shear tests by taking the effect of residual strength into account. For each model, load during debonding and its maximum value are given by closed-form expressions, which are then checked against experimental data reported in the literature. It is shown that using the interfacial mechanical properties extracted from one geometry, the debonding load of tests with different bond lengths and widths can be predicted without any fitting procedure. Moreover, effective bond length formulae are suggested for each model; one is the straightforward extension (accounting for residual strength) of a formula available in the Standards. The results illustrate the importance of considering residual strength in direct shear tests, even at debonding onset, with its effect being nonetheless higher for long bond lengths.
RESUMEN
Zinc hydroxyfluoride (Zn(OH)F) sonocatalyst was prepared by using solvothermal method and was characterized by using various techniques. The sonocatalytic degradation of ampicillin (AMP) in water by sonolysis, bare ZnO and Zn(OH)F was investigated in terms of AMP removal, mineralization, detoxification of solution, and remaining by-products at the end of process. Results revealed that the sonocatalytic performance of Zn(OH)F was significantly greater than that of bare ZnO. Under the optimum conditions, the removal percentage of AMP by Zn(OH)F was â¼97% after 90 min reaction, while 51% and 36% COD and TOC removal were achieved after 120 min reaction, respectively. The study of Zn(OH)F stability revealed that the degradation efficiency of AMP was reduced by only 5% even after being reused for four experiments. The toxicity of initial and treated solutions was assessed by using agar-well diffusion method and ToxTrak™ toxicity assay, and the results indicated a substantial reduction in the toxicity of solution after the treatment. The formation of some by-products during the sonolysis and sonocatalysis was evaluated by LC-HR-MS/MS method. LC-HR-MS/MS results showed that the concentration of most by-products, which were produced after 90 min treatment by US/Zn(OH)F process, was considerably lower than those obtained during sonolysis and US/ZnO processes.
Asunto(s)
Ampicilina/química , Antibacterianos/química , Fluoruros/química , Nanopartículas/química , Compuestos de Zinc/química , Ampicilina/toxicidad , Antibacterianos/toxicidad , Catálisis , Escherichia coli/efectos de los fármacos , Escherichia coli/crecimiento & desarrollo , Fluoruros/toxicidad , Concentración de Iones de Hidrógeno , Nanopartículas/toxicidad , Sonicación , Ondas Ultrasónicas , Compuestos de Zinc/toxicidadRESUMEN
AIM: The present study was carried out to determine the effects of ZnO nanoparticles (ZnO-NPs) on intestinal function and pathophysiological alteration. MATERIALS & METHODS: ZnO-NPs were synthesized and their characterizations were performed using various techniques. The Wistar male rats fed with normal diet and/or high fat diet (HFD) for 8 weeks and then orally received ZnO-NPs (5, 50 and 100 mg/kg bodyweight) for 28 days. The oxidative stress (SOD, CAT, GPx), inflammatory (TNF-α, iNOS) and apoptosis pathways (Bcl2, Bax and p53) genes expression and protein levels were measured by real-time polymerase chain reaction and available kit, respectively. The activity of Caspase-3, antioxidant capacity, as well as inflammatory markers were determined. The histological alterations of the large and small intestine were also evaluated with haematoxylin and eosin (H&E) as well as TdT dUTP nick end labeling (TUNEL) assay. The biochemical factors, viability and antioxidant activity were also determined in Caco-2 cells. RESULTS: It was found that the antioxidant enzymes activity and genes expression markedly increased, while inflammatory and apoptosis pathways and TNF-α levels significantly decreased in the intestine of HFD-fed rats treated with 5 mg/kg ZnO-NPs. Intestinal morphological changes were also restored by 5 mg/kg ZnO-NPs in HFD group. CONCLUSION: Treatment of rats with 50 and 100 mg/kg ZnO-NPs significantly induced intestinal injury, while treatment with 5 mg/kg ZnO nanoparticle normalized intestinal functions and structure. This study showed the synergistic effects of ZnO-NPs and HFD administration on liver enzyme, oxidative stress, apoptosis, inflammation, morphological changes and cell toxicity.
Asunto(s)
Mucosa Intestinal/metabolismo , Nanopartículas del Metal/administración & dosificación , Estrés Oxidativo/efectos de los fármacos , Óxido de Zinc/administración & dosificación , Animales , Antioxidantes/metabolismo , Apoptosis/efectos de los fármacos , Células CACO-2 , Supervivencia Celular/efectos de los fármacos , Dieta Alta en Grasa/efectos adversos , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Mucosa Intestinal/efectos de los fármacos , Masculino , Nanopartículas del Metal/química , Estrés Oxidativo/genética , Ratas , Especies Reactivas de Oxígeno/metabolismo , Óxido de Zinc/químicaRESUMEN
The degradation of sulfamethoxazole (SMX) by a synthesized hierarchical magnetic zinc oxide based composite ZnO@g-C3N4 (FZG) was examined. Hierarchical FZG was synthesized by using Fe3O4 nanoparticle as the magnetic core and urea as the precursor for in situ growth of g-C3N4 on the surface of petal-like ZnO. The effect of catalyst dosage (0.4-0.8 g/L), solution pH (3-11) and airflow rate (0.5-2.5 L/min) on the SMX removal efficiency and the optimization of process was studied by response surface methodology (RSM) based on central composite design (CCD). The obtained RSM model with R2 = 0.9896 showed a satisfactory correlation between the predicted values and experimental results of SMX removal. Under the optimum conditions, i.e. 0.65 g/L photocatalyst concentration, pH = 5.6 and airflow rate = 1.89 L/min, 90.4% SMX removal was achieved after 60 min reaction. The first-order kinetic rate constant for SMX removal by using FZG was 0.0384 min-1 while the rate constant by commercial ZnO was 0.0165 min-1. Moreover, under the optimum conditions, about 64% COD removal and 45% TOC removal and a considerable reduction in toxicity were observed. The analysis of generated intermediates during the photocatalytic degradation of SMX was conducted by LC-HR-MS/MS method and a degradation pathway was proposed.
RESUMEN
Herein, a petal-like photocatalyst, Fe3O4-ZnO@g-C3N4 (FZG) with different g-C3N4 to ZnO ratios was synthesized with hierarchical structure. The FZG1 photocatalyst, having the weight ratio of 1:1 for the initial urea and Fe3O4-ZnO (Fe-ZnO), presented the highest sulfamethoxazole (SMX) degradation rate of 0.0351 (min-1), which was 2.6 times higher than that of pristine ZnO. Besides the facile separation, the performance of photocatalyst was improved due to the function of iron oxide as an electron acceptor that reduced the electron/hole recombination rate. The coating of g-C3N4 on the Fe-ZnO surface not only acted as a protective layer for ZnO against photocorrosion, but it also enhanced the photocatalytic activity of the catalyst for SMX degradation through the heterojunction mechanism. By using the FZG1 photocatalyst, 95% SMX removal was obtained after 90â¯min reaction, while 47% COD and 30% TOC removal were achieved after 60â¯min treatment under a low energy-consuming UV lamp (10â¯W). Moreover, a substantial reduction in the solution toxicity was shown after the treatment, as compared with the SMX solution before treatment. The LC-HR-MS/MS analysis results showed that the concentration of most detected by-products produced after 90â¯min reaction by FZG1 was considerably lower than those obtained using other synthesized photocatalysts. By performing radical scavenging experiments, OH° radical was found to be the major reactive species. The FZG1 photocatalyst also displayed excellent reusability in five cycles and the leaching of zinc and iron ions was reduced by 54% and â¼100%, respectively, after coating Fe-ZnO with g-C3N4.
Asunto(s)
Ecotoxicología , Nitrilos/química , Sulfametoxazol/aislamiento & purificación , Catálisis , Corrosión , Compuestos Férricos/química , Procesos Fotoquímicos , Espectrometría de Masas en Tándem , Óxido de Zinc/químicaRESUMEN
The presence of antibiotics in water bodies has received increasing attention since they are continuously introduced and detected in the environment and may cause unpredictable environmental hazards and risks. The photocatalytic degradation of sulfamethoxazole (SMX) by ZnO in the presence of fluoride ions (F-ZnO) was evaluated. The effects of operating parameters on the efficiency of SMX removal were investigated by using response surface methodology (RSM). Under the optimum condition, i.e. photocatalyst dosageâ¯=â¯1.48â¯g/L, pH 4.7, airflow rateâ¯=â¯2.5â¯L/min and the concentration of fluoride ionsâ¯=â¯2.505â¯mM, about 97% SMX removal was achieved by F-ZnO after 30â¯min of reaction. The mechanism of reactions, COD removal efficiency and reaction kinetics were also investigated under optimum operating conditions. In addition, about 85% COD reduction was obtained after 90â¯min photocatalytic reaction. The pseudo-first-order kinetics rate constants for the photodegradation of SMX were found to be 0.099, 0.058 and 0.048 min-1 by F-ZnO, ZnO and TiO2 (P25), respectively. The figure-of-merit electrical energy per order (EEO) was used for estimating the electrical energy efficiency, which was shown to be considerably lower than the energy consumption for the reported research on removal of SMX by photocatalytic degradation under UV irradiation. Toxicity assays were conducted by measuring the inhibition percentage (PI) towards E. coli bacteria strain and by agar well diffusion method. The results showed that after 30â¯min of reaction, the toxicity of the treated solutions by all photocatalysts fell within the non-toxic range; however, the reduction in toxicity by F-ZnO was faster than those by ZnO and P25. Despite the positive effects of surface fluorination of ZnO on the SMX and COD removal and reaction kinetics, its lower stability compared to ZnO and P25 in the repeated experiments gave rise to some doubts about its performance from a practical point of view.
Asunto(s)
Sulfametoxazol/química , Eliminación de Residuos Líquidos/métodos , Óxido de Zinc/química , Antibacterianos/química , Catálisis , Escherichia coli/efectos de los fármacos , Fluoruros/química , Concentración de Iones de Hidrógeno , Cinética , Fotólisis , Pruebas de Toxicidad/métodos , Rayos Ultravioleta , Aguas Residuales/química , Aguas Residuales/toxicidad , Contaminantes Químicos del Agua/químicaRESUMEN
The presence of emerging contaminants such as pharmaceuticals in natural waters has raised increasing concern due to their frequent appearance and persistence in the aquatic ecosystem and the threat to health and safety of aquatic life, even at trace concentrations. Conventional water treatment processes are known to be generally inadequate for the elimination of these persistent contaminants. Therefore, the use of advanced oxidation processes (AOPs) which are able to efficiently oxidize organic pollutants has attracted a great amount of attention. The main limitation of AOPs lies in their high operating costs associated with the consumption of energy and chemicals. Fenton-based processes, which utilize nontoxic and common reagents and potentially can exploit solar energy, will considerably reduce the removal cost of recalcitrant contaminants. The disadvantages of homogeneous Fenton processes, such as the generation of high amounts of iron-containing sludge and limited operational range of pH, have prompted much attention to the use of heterogeneous Fenton processes. In this review, the impacts of some controlling parameters including the H2O2 and catalyst dosage, solution pH, initial contaminants concentrations, temperature, type of catalyst, intensity of irradiation, reaction time and feeding mode on the removal efficiencies of hetero/homogeneous Fenton processes are discussed. In addition, the combination of Fenton-type processes with biological systems as the pre/post treatment stages in pilot-scale operations is considered. The reported experimental results obtained by using Fenton and photo-Fenton processes for the elimination of pharmaceutical contaminants are also compiled and evaluated.