Catalytic electrodes' characterization study serving polluted water treatment: environmental healthcare and ecological risk assessment.

Pesticide residues in the environment have irreparable effects on human health and other organisms. Hence, it is necessary to treat and degrade them from polluted water. In the current work, the electrochemical removal of the fenitrothion (FT), trifluralin (TF), and chlorothalonil (CT) pesticides were performed by catalytic electrode. The characteristics of SnO2-Sb2O3, PbO2, and Bi-PbO2 electrodes were described by FE-SEM and XRD. Dynamic electrochemical techniques including cyclic voltammetry, electrochemical impedance spectroscopy, accelerated life, and linear polarization were employed to investigate the electrochemical performance of fabricated electrodes. Moreover, evaluate the risk of toxic metals release from the catalytic electrode during treatment process was investigated. The maximum degradation efficiency of 99.8, 100, and 100% for FT, TF, and CT was found under the optimal condition of FT, TF, and CT concentration 15.0 mg L-1, pH 7.0, current density 7.0 mA cm-2, and electrolysis time of 120 min. The Bi-PbO2, PbO2, and SnO2-Sb2O3 electrodes revealed the oxygen evolution potential of 2.089, 1.983, 1.914 V, and the service lifetime of 82, 144, and 323 h, respectively. The results showed that after 5.0 h of electrolysis, none of the heavy metals such as Bi, Pb, Sb, Sn, and Ti were detected in the treated solution.

Simultaneous electrochemical degradation of pesticides from the aqueous environment using Ti/SnO2-Sb2O3/PbO2/Bi electrode; process modeling and mechanism insight.

In this work, modified Bi-PbO2 electrode was fabricated and employed for simultaneous degradation of fenitrothion (FT), trifluralin (TF), and chlorothalonil (CT) from synthetic and pesticide wastewater through the anodic oxidation process. A novel high-performance liquid chromatography method was developed and optimized to identify the pesticides simultaneously. Quadratic models were developed to investigate the effects of main operating parameters and predict the degradation efficiencies of the treatment processes. The R2 of the degradation efficiencies were obtained of 0.9847, 0.9910, and 0.9821 for FT, TF, and CT, respectively, which indicates the degree of conformity between the experimental and the actual values of degradation efficiencies, and the adjusted R2 values for the degradation efficiency of FT, TF, and CT in proposed models were 0.9826, 0.9898, and 0.9796, and the values of the predicted R2 were 0.9792, 0.9875, and 0.9755, respectively. The maximum degradation efficiencies of 99.7, 100, and 100% obtained for FT, TF, and CT, respectively, under the optimal operating condition of FT, TF, and CT concentration of 10.0, 6.0, and 8.0 mg L-1, respectively, pH 6.0, the current density 6.0 mA cm-2, and electrolysis time of 60 min. Chemical oxygen demand removal and energy consumption were 64.7% and 5.1 kWh m-3. Eventually, the generated intermediates and other produced species of pesticides through the treatment process was evaluated using a gas chromatography-mass spectrometry method, and their degradation pathways were proposed.

Response surface modeling of ceftriaxone removal from hospital wastewater.

In recent decades, an emerging concern of widespread antimicrobial resistance has been raised due to the existence of pharmaceutical samples such as antibiotics in an aqueous medium. Herein, antibiotic ceftriaxone (CTX) removal from hospital wastewater employing a hybrid process of electrocoagulation (EC) and adsorption (AD) was investigated. The response surface methodology (RSM) was employed to study the influences of main operating variables, including initial CTX concentration, pH, current density, reaction time, and chitosan dosage, on the removal efficiency of the treatment process. Under the optimum condition of the employed EC/AD hybrid treatment process, where initial CTX concentration, pH solution, the current density, adsorbent dosage, and reaction time were set at 20.0 mg L-1, 7.5, 6.0 mA cm-2, 0.75 g L-1, and 12.5 min, respectively, the removal efficiency of 100% was achieved. Analysis of variance (ANOVA) confirmed that the developed quadratic treatment model is highly significant. The applied EC/AD hybrid treatment process revealed the electrical energy consumption of 0.84 kWh m-3 and 0.2168 kWh (g Al)-1 per cubic meter of hospital wastewater and gram of consumed aluminum electrode, respectively. The second-order kinetic model with R2 of 0.9514 and the Langmuir isotherm model with R2 of 0.973 best fit the developed EC/AD hybrid treatment process, and qm was found to be 111.1 mg g-1. The obtained experimental results confirmed that the CTX concentration of the hospital wastewater was reduced to zero after applying the EC/AD hybrid process.

Iron-modified activated carbon derived from agro-waste for enhanced dye removal from aqueous solutions.

BACKGROUND AND AIM: Finding a cost-effective adsorbent can be an obstacle to large-scale applications of adsorption. This study used an efficient activated carbon adsorbent based on agro-waste for dye removal. METHODS: Pistachio shells as abundant local agro-wastes were used to prepare activated carbon. Then, it was modified with iron to improve its characteristics. Acid red 14 was used as a model dye in various conditions of adsorption (AR14 concentration 20-150 mg L-1, pH 3-10, adsorbent dosage 0.1-0.3 g L-1, and contact time 5-60 min). RESULTS: A mesoporous adsorbent was prepared from pistachio shells with 811.57 m2 g-1 surface area and 0.654 cm3 g-1 pore volume. Iron modification enhanced the characteristics of activated carbon (surface area by 33.3% and pore volume by 64.1%). Adsorption experiments showed the high effectiveness of iron-modified activated carbon for AR14 removal (>99%, >516 mg g-1). The adsorption followed the pseudo-second kinetic model (k = 0.0005 g mg-1 min-1) and the Freundlich isotherm model (Kf = 152.87, n = 4.61). Besides, the reaction occurred spontaneously (ΔG0 = -36.65 to -41.12 kJ mol-1) and was exothermic (ΔH0 = -41.86 kJ mol-1 and ΔS0 = -3.34 J mol-1 K-1). CONCLUSION: Iron-modified activated carbon derived from pistachio shells could be cost-effective for the treatment of industrial wastewater containing dyes.

Electro-Fenton approach in oxidative degradation of dimethyl phthalate - The treatment of aqueous leachate from landfills.

Herein, the dimethyl phthalate (DMP) contamination, as an emerging pollutant, has been cost-effectively removed from landfill leachate through an advanced oxidation process, that is the electro-Fenton (EF) process. For this purpose, a quadratic polynomial model was developed via response surface methodology (RSM). Furthermore, the analysis of variance (ANOVA) was performed for evaluating the significance of the proposed assumptions. The actual removal rate of 99.1% was obtained with optimal values of 4 mg L-1 of initial DMP concentration, 50 mM Na2SO4, 600 µL L-1 H2O2, 8-minute electrolytic time, solution pH 3 and 6 mA cm-2 current density for the process variables and was consistent with the expected 99.6% removal rate. Satisfactory correlation coefficients were obtained, and a non-significant value of 0.0618 for model mismatch confirmed that the proposed model is extremely important and can successfully predict the effectiveness of DMP removal. The kinetics of the process and the effect of the presence of some radical scavengers were studied to understand the exact mechanism of DMP degradation. Therefore, it was observed that the reaction of hydroxyl radicals with DMPs followed the first-order kinetics model. Moreover, it was established that the optimal ratio of H2O2/Fe2+ mole was 1.6 and the electricity consumption was 0.157 kWh m-3. The elaborated treatment model used to remove DMP from landfill leachate showed that DMP contamination was effectively removed with a 95.6% removal efficiency in the investigating process.

Adsorption of tetracycline antibiotic onto modified zeolite: Experimental investigation and modeling.

Artificial Neural Networks (ANNs) model and Adaptive Neuro-Fuzzy Inference System (ANFIS) were used to estimate and predict the removal efficiency of tetracycline (TC) using the adsorption process from aqueous solutions. The obtained results demonstrated that the optimum condition for removal efficiency of TC were 1.5 g L-1 modified zeolite (MZ), pH of 8.0, initial TC concentration of 10.0 mg L-1, and reaction time of 60 min. Among the different back-propagation algorithms, the Marquardt-Levenberg learning algorithm was selected for ANN Model. The log sigmoid transfer function (log sig) at the hidden layer with ten neurons in the first layer and a linear transfer function were used for prediction of the removal efficiency. Accordingly, a correlation coefficient, mean square error, and absolute error percentage of 0.9331, 0.0017, and 0.56% were obtained for the total dataset, respectively. The results revealed that the ANN has great performance in predicting the removal efficiency of TC.•ANNs used to estimate and predict tetracycline antibiotic removal using the adsorption process from aqueous solutions.•The model's predictive performance evaluated by MSE, MAPE, and R2.

A rapid and efficient removal approach for degradation of metformin in pharmaceutical wastewater using electro-Fenton process; optimization by response surface methodology.

Presence of emerging contaminants such as pharmaceutical products in aquatic environments has received high concern due to their undesirable effect on wildlife and human health. Current work deals with developing a treatment model based on the electro- Fenton (EF) process for efficient removal of metformin (MET) from an aqueous medium. The obtained experimental results revealed that over the reaction time of 10 min and solution pH of 3, the maximum removal efficiency of 98.57% is achieved where the value of MET initial concentration, current density, and H2O2 dosage is set at 10 mg.L-1, 6 mA.cm-2, and 250 µL.L-1, respectively, which is in satisfactory agreement with the predicted removal efficiency of 98.6% with the desirability of 0.99. The presence of radical scavengers throughout the mineralization of MET under the EF process revealed that the generation of •OH radicals, as the main oxidative species, controlled the degradation mechanism. The obtained kinetics data best fitted to the first order kinetic model with the rate constant of 0.4224 min-1 (R2 = 0.9940). The developed treatment process under response surface methodology (RSM) was employed for modeling the obtained experimental data and successfully applied for efficient removal of the MET contaminant from pharmaceutical wastewater as an adequate and cost-effective approach.

Electrochemical treatment of pharmaceutical wastewater through electrosynthesis of iron hydroxides for practical removal of metronidazole.

Antibiotics as the severe contaminants of aqueous environments were received growing attention during the last decades. The current work is the first report on investigating the potency and efficiency of electrocoagulation process in the successful removal of metronidazole (MNZ) from pharmaceutical wastewater using response surface methodology based on central composite design. The applied method by optimizing the independent and combined effects of significant variables which affecting the EC process enhanced the removal efficiency of MNZ. Analysis of variance was applied to verify the significance of independent variables solely and their interactions. The best removal efficiency of 100% found under the optimal operating condition of initial MNZ concentration 21.6 mg L-1, pH 8.2, current density 6.0 mA cm-2, inter-electrode distance 3 cm, and reaction time of 14.6 min. Isotherm investigations revealed that the Langmuir model with the R2 of 0.994 best fitted to the obtained experimental equilibrium results. The fast adsorption of MNZ on the surface of Fe(OH)3 and [Fe(OH)2]+ with the equilibrium time of 15 min confirmed that the kinetics of the electrocoagulation process follow the pseudo-second-order model (R2 = 0.962). The electrocoagulation process under the optimal operating condition revealed that the electrical energy consumption per each m3 of treated pharmaceutical wastewater, per each g of MNZ, removed, and per each kg of Fe electrode consumed, were found to be 0.516 kWh m-3, 0.0234 kWh g-1, and 0.0436 kWh kg-1, respectively.

In situ generation of hydroxyl radical for efficient degradation of 2,4-dichlorophenol from aqueous solutions.

Since 2,4-dichlorophenol (2,4-DCP) as a priority pollutant is used in numerous industrial processes, its removal from the aqueous environment is of utmost importance and desire. Herein, the authors describe an electrochemical treatment process for efficient removal of 2,4-DCP from aqueous solutions using electro-Fenton (EF) process. Response surface methodology (RSM) was applied to optimize the operating parameters. Analysis of variance (ANOVA) confirmed the significance of the predicted model. The effect of independent variables on the removal of 2,4-DCP was investigated and the best removal efficiency of 98.28% achieved under the optimal experimental condition including initial pH of 3, H2O2 dosage of 80 µL, initial 2,4-DCP concentration of 3.25 mg L-1, current density of 3.32 mA cm-2, and inter-electrode distance of 5.04 cm. The predicted removal efficiency was in satisfactory agreement with the obtained experimental removal efficiency of 99.21%. According to the obtained polynomial model, H2O2 dosage revealed the most significant effect on degradation process. The kinetic investigation revealed that the first-order model with the correlation coefficient of 0.9907 and rate constant (Kapp) of 0.831 min-1 best fitted with the experimental results. Generation of the hydroxyl radicals throughout the EF process controlled the degradation process.

Circulatory Levels of C-X-C Motif Chemokine Ligands 1, 9, and 10 Are Elevated in Patients with Ischemic Stroke.

OBJECTIVE: Inflammation plays a significant role in the development of ischemic stroke. CXC chemokines play pleiotropic roles in prolonged leukocyte locomotion, astrocyte migration/activation, and neural attachment/sprouting in response to focal stroke. In this study, we aimed to explore the changes in serum levels of three chemokines, C-X-C motif chemokine ligand 1 (CXCL1), C-X-C motif chemokine ligand 9 (CXCL9), and C-X-C motif chemokine ligand 10 (CXCL10), in ischemic stroke patients at the time of admission and before discharge from the hospital ward. MATERIALS AND METHODS: In this study, we recruited 43 unrelated ischemic stroke patients using an easy convenience method or accidental sampling which is a type of non-probability sampling that involves the sample being drawn from that part of the population that is close to hand. We also enrolled 50 genetically unrelated healthy controls showing no history of neurologic, cardiovascular, or inflammatory diseases. Serum levels of the considered chemokines were measured by enzyme-linked immunosorbent assay (ELISA) in patients and healthy controls. RESULTS: No significant difference was observed in ischemic stroke patients following hospitalization and prior discharging from the hospital; however, there was a significant difference in serum levels of CXCL9 and CXCL10 between patients and healthy controls. We also found that the level of the chemokine was not related to gender or medical therapy. It appears that CXCL9 and CXCL10 are more predisposing factors and play a direct role in stroke considering that they were higher in patients than in healthy controls. CONCLUSION: We believe that this study might be used as a basis for further studies on more effective medication regimens to prevent the onset and subsequent complications of stroke. However, these mediators are useful diagnostic and prognostic tools rather than therapeutic tools.

Histopathological findings of endometrial specimens in abnormal uterine bleeding.

PURPOSE: The aim of this study was to assess the frequency of different histopathological findings obtained from dilatation and curettage (D&C) specimens in patients with abnormal uterine bleeding (AUB). METHODS: In a retrospective review of 591 specimens, the included subjects were all women with AUB who underwent D&C between 2002 and 2006 in Be'sat Hospital, Tehran, Iran. The pathological diagnoses were analyzed in four groups from normal to malignant endometrium. The pathological groups were evaluated for patients' characteristics including demographic data and medical history. RESULTS: The majority of patients (61.6%) were in the 41-50 year age group. Totally, 81.4% of patients had normal pathology. The disordered proliferative endometrium/polyps, hyperplasia, and malignant pathology were found in 15.4, 2.5, and 0.7% of specimens, respectively. The abnormal pathologies were seen more among patients with postmenopausal status, nulli-/primigravid women, and those with hypertension, diabetes, hypothyroidism, and polycystic ovary syndrome. CONCLUSIONS: The proliferative endometrium and secretory endometrium were the most common histopathological observations in AUB patients in our region, and except normal endometrium, disordered proliferative endometrium was the most common cause of AUB.