Degradation of 2,4-dinitrotoluene in aqueous solution by dielectric barrier discharge plasma combined with Fe-RGO-BiVO4 nanocomposite.

2,4-Dinitrotoluene (2,4-DNT) as a priority and hazardous pollutant, is widely used in industrial and military activities. In this study the synergistic effect of Fe-RGO-BiVO4 nanocomposite in a non-thermal dielectric barrier discharge plasma reactor (NTP-DBD) for degrading 2,4-DNT was evaluated. Preparation of the Fe-RGO-BiVO4 nanocomposite was done by a stepwise chemical method depositing Fe and reduced graphene oxide (RGO) on BiVO4. Field emission scanning electron microscopy (FESEM), X-ray diffraction analysis (XRD), UV-vis diffuse reflectance spectra (DRS), and energy-dispersive X-ray spectroscopy mapping (EDS-mapping) validated the satisfactory synthesis of Fe-RGO-BiVO4. To find the optimal conditions and to determine the interaction of model parameters, a central composite design (RSM-CCD) had been employed. 2,4 DNT can be completely degraded at: initial 2,4-DNT concentration of 40 mg L-1, Fe-RGO-BiVO4 dosage of 0.75 g L-1, applied voltage of 21kV, reaction time of 30 min and pH equal to 7, while the single plasma process reached a degradation efficiency of 67%. The removal efficiency of chemical oxygen demand (COD) and total organic carbon (TOC) were 90.62% and 88.02% at 30 min contact time, respectively. Results also indicated that average oxidation state (AOS) and carbon oxidation state (COS) were enhanced in the catalytic NTP-DBD process, which demonstrate the effectiveness of proposed process for facilitating biodegradability of 2,4-DNT.

A review of novel methods for Diuron removal from aqueous environments.

Runoff from intensive agriculture, which contains many sources of pollutants, including herbicides, for instance, Diuron, has threatened the environment and human health. The intrusion of these toxins into water sources poses a serious challenge to human society, and the rising release of these toxins has always been of concern to water researchers. The consequences of the release of these toxins into water sources are destructive and debilitating to human life. Today, the contamination of surface water and wastewater by pesticide residues, especially from agricultural activities and pesticide factories, has grown significantly. One of the pesticides commonly applied around the world is Diuron. There are various techniques for removing Diuron, the most important of which are adsorption and advanced oxidation. This review presents the characteristics, mechanisms, and emerging methods of removing Diuron. The use of absorbents, such as sludge-derived modified biochar (SDMBC600) and bottom ash waste (BAW-200), is discussed in detail. Additionally, the main features, benefits, and limitations of new technologies like hydrodynamic cavitation are enumerated. The effectiveness of novel adsorbents in Diuron removal is also discussed.

Exposure of the static magnetic fields on the microbial growth rate and the sludge properties in the complete-mix activated sludge process (a Lab-scale study).

BACKGROUND: In this study, the effect of static magnetic fields (SMFs) on improving the performance of activated sludge process to enhance the higher rate of microbial growth biomass and improve sludge settling characteristics in real operation conditions of wastewater treatment plants has been investigated. The effect of SMFs (15 mT), hydraulic retention time, SRT, aeration time on mixed liquor suspended solids (MLSS) concentrations, mixed liquor volatile suspended solids (MLVSS) concentrations, α-factor, and pH in the complete-mix activated sludge (CMAS) process during 30 days of the operation, were evaluated. RESULTS: There were not any differences between the concentration of MLSS in the case (2148.8 ± 235.6 mg/L) and control (2260.1 ± 296.0 mg/L) samples, however, the mean concentration of MLVSS in the case (1463.4 ± 419.2 mg/L) was more than the control samples (1244.1 ± 295.5 mg/L). Changes of the concentration of MLVSS over time, follow the first and second-order reaction with and without exposure of SMFs respectively. Moreover, the slope of the line and, the mean of α-factor in the case samples were 6.255 and, - 0.001 higher than the control samples, respectively. Changes in pH in both groups of the reactors were not observed. The size of the sluge flocs (1.28 µm) and, the spectra of amid I' (1440 cm-1) and II' (1650 cm-1) areas related to hydrogenase bond in the case samples were higher than the control samples. CONCLUSIONS: SMFs have a potential to being considered as an alternative method to stimulate the microbial growth rate in the aeration reactors and produce bioflocs with the higher density in the second clarifiers.

The effect of the combined system of hydrodynamic cavitation, ozone, and hydrogen peroxide on chlorophyll a and organic substances removal in the raw water.

Increased levels of nutrients and algae can cause drinking water problems in communities. Harmful algal blooms affect humans, fish, marine mammals, birds, and other animals. In the present study, we investigated the use of a combined system [Hydrodynamic Cavitation, Ozone (O3), and Hydrogen Peroxide (H2O2)] on the removal of Chlorophyll a and Organic substances in the raw water was investigated. The Effect of different operating conditions such as pH, cavitation time, pressure, distance, flow rate, ozone dose, and hydrogen peroxide concentration was studied. Utilizing the Taguchi design method, experiments were planned and optimized. The combined system treatment yielded a maximum reduction in Chlorophyll a and Total Organic Carbon (TOC) at an optimum condition of pH 5, cavitation pressure 5 bar, flow rate of 1 m3/h, a distance of 25 cm from the orifice plate, O3 3 g/h and 2 g/l of H2O2 concentrations. The most efficient factor in the degradation of TOC and Chlorophyll a, was cavitation pressure based on the percentage contributions of each parameter (38.64 percent and 35.05 percent, respectively). H2O2 was found to have the most negligible impact on degradation efficiency (4.24 percent and 4.11 percent, respectively).

The best location for the application of static magnetic fields based on biokinetic coefficients in complete-mix activated sludge process.

The use of the kinetic coefficients for the mathematical expression of the biochemical processes and the relationship between the effective parameters is importance. Change of the biokinetic coefficients in the complete-mix activated sludge processes were calculated for 1 month operation of the activated sludge model (ASM) in a Lab-scale in three series. 15 mT intensity of static magnetic fields (SMFs) applied on the aeration reactor (ASM 1), clarifier reactor (ASM 2) and, sludge returning systems (ASM 3) for 1 h, daily. During the operation of the systems, five basic biokinetic coefficients such as maximum specific substrate utilization rate (k), heterotrophic half-saturation substrate concentration (Ks), decay coefficient (kd), yield coefficient (Y) and, maximum specific microbial growth rate (µmax) were determined. The rate of k (g COD/g Cells.d) in ASM 1 was 2.69% and, 22.79% higher than ASM 2 and, ASM 3. The value of Ks (mg COD/L) was 54.44 and, 71.13 (mg/L) lower than the ASM 2 and, ASM 3. The rate of kd ASM 1, ASM 2 and, ASM 3 was 0.070, 0.054 and, 0.516 (d-1). The value of Y (kg VSS/kg COD) in ASM 1 was 0.58% and, 0.48% lower than ASM 2 and, ASM 3. The rate of µmax (d-1) in ASM 1 was 0.197, this value for ASM 2 and ASM 3 were 0.324 and 0.309 (d-1). Related to the biokinetic coefficients analyses the best location for the application of 15 mT SMFs was the aeration reactor, where the present of oxygen, substrate and, SMFs have the greatest impact on the positive changes of these coefficients.

Kinetic studies of dexamethasone degradation in aqueous solution via a photocatalytic UV/H2O2/MgO process.

Wastewaters discharged from different industries and hospitals may contain pharmaceuticals, especially dexamethasone (DEX). Thus, we applied the UV/H2O2 photocatalytic method in the presence of the MgO nanoparticles to remove dexamethasone from synthetic wastewater. Moreover, the effects of parameters such as pH (3-11), hydrogen peroxide concentration (1-8 mM), initial DEX concentration (5-30 mg/L), and catalyst dosage (0.01-0.2 g/L) during the reaction times (0-30 min) were investigated. Furthermore, the efficiency of UV/H2O2 in the presence and absence of catalysts was investigated. The photocatalyst is characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and Fourier-transform infrared spectroscopy (FTIR) techniques. It was found that the removal rate was enhanced by decreasing pH and the initial dexamethasone concentration. The removal rate was enhanced somewhat with concentrations of hydrogen peroxide and MgO. In the case of UV/H2O2/MgO, 87% removal efficiency was achieved, under the optimal conditions: pH 3, contact time of 30 min, dexamethasone concentration of 20 mg/L, H2O2 of 0.5 mM, and UV radiation of 55 watts. The kinetic data indicated that the reaction followed the second-order kinetic model. The results showed that the UV/H2O2 photochemical process can efficiently remove dexamethasone from aqueous in the presence of a MgO catalyst, and the mineralization efficiency was reached at about 98%.

Step-scheme BiVO4/WO3 heterojunction photocatalyst under visible LED light irradiation removing 4-chlorophenol in aqueous solutions.

In the present study, photodegradation of 4-chlorophenol (4-CP) using a step-scheme BiVO4/WO3 heterostructure under visible LED light irradiation (Vis LED) from aqueous solutions was investigated. The photocatalyst was synthesized through the hydrothermal process and characterized physically and chemically via X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray (EDX), and Brunnauer-Emmett-Teller (BET) techniques. The effects of the operational parameters i.e., solution pH, contact time, nanocomposite dosage, and initial 4-CP concentration were evaluated. Results indicated that BiVO4/WO3/Vis LED process has higher efficiency in 4-CP degradation than BiVO4/Vis LED, WO3/Vis LED, and BiVO4/WO3 systems. At BiVO4/WO3 concentration of 0.125 g/L, initial pH of 7, and initial 4-CP concentration of 25 mg/L, complete degradation of 4-CP (>97%) was achieved in reaction time of 60 min. The phenol, chlorobenzene, catechol, 4-chlorocatechol, 5-chloro-1,2,4-benzenetriol, hydroquinone, hydroxyhydroquinone, p-benzoquinone, o-benzoquinone, formic acid, acetic acid, and oxalic acid were identified as the major intermediates of 4-CP degradation. In optimal condition, 67.5% and 88.5% of TOC and COD removal rates were obtained in 120 min contact time, respectively. The degradation of 4-CP was pseudo-first-order kinetics. Through the use of tert-Butyl alcohol (TBA) and ethylenediamine tetraacetic acid (EDTA) as radical scavengers, hydroxyl radicals and holes were identified as the main active species in photocatalytic degradation. Also, a tentative pathway for 4-CP degradation using the Vis LED/BiVO4/WO3 process was proposed.

Modified bone char with C-MgO as a green antibacterial household water treatment filter: Comparing the microbial quality with refrigerator cartridge filters.

The present study examines the efficiency of modified bone char (BC) with C-MgO nanoparticles (MBC-C-MgO) as media in a cartridge filter as an antibacterial agent to produce a new filter. The filters were operated in a continuous mode using a pre-static pump. MBC-C-MgO were produced and modified with sucrose through the co-precipitation method. The microbial quality of effluent water samples was compared with commercial refrigerator cartridge filters using a heterotrophic plate count (HPC) test and SEM analysis. The results showed that the effluent water from the filter with MBC-C-MgO media had the lowest HPC (177 CFU/mL) compared to bioceramic (271 CFU/mL) and carbon (500 CFU/mL) under similar experimental conditions after 4 months of operation. Maximum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests were determined using the broth dilution method on Escherichia coli (ATCC 25922) and Enterococcus faecalis (ACC 29212). The MIC results for E. faecalis and E. coli were 156.25 and 312.5 µg/mL, respectively. Furthermore, the MBC results for E. faecalis and E. coli were 312.5 and 625 µg/mL. The experimental results obviously showed the antibacterial properties of C-MgO nanoparticles and the MBC-C-MgO.

Moving-bed biofilm reactor combined with three-dimensional electrochemical pretreatment (MBBR-3DE) for 2,4-D herbicide treatment: application for real wastewater, improvement of biodegradability.

2,4-Dichlorophenoxyacetic acid (2,4-D) is a herbicide that is considered as a carcinogenic and highly toxic contaminant, and due to its biological and chemical stability, its degradation is very difficult. Therefore, this study aimed to investigate a hybrid system's efficiency of three-dimensional electrochemical (3DE) process and a moving bed biofilm reactor (MBBR) in removing 2,4-D herbicides from aqueous solutions. In this experimental study, the electrochemical degradation of 2,4-D herbicide in a 3DE process with a G/ß-PbO2 anode was first investigated as a pretreatment process. Then, in the post-treatment stage, MBBR with continuous flow was used. The amount of aeration in the MBBR reactor was 4 L min-1, and the amount of dissolved oxygen (DO) was in the range of 3-5 mg L-1. The effect of various parameters such as hydraulic retention time (HRT) and filling ratio were investigated. The amount of sewage injection was set between 0.001-0.004 L min-1. Routine microbiological biochemical tests were used to detect bacteria. BOD5/COD, COD/TOC, AOS, and COS ratio parameters were used to determine the biodegradability of 2.4-D due to the effluent of the 3DE process. The results showed that with increasing current density, decreasing pH, decreasing herbicide concentration and increasing electrolysis time, the herbicide degradation efficiency increased by 3DE pretreatment process. Based on the results of MBBR post-treatment process efficiency, with increasing HRT and filling ratio, the herbicide removal efficiency increased. According to the results, the highest removal efficiencies of 2,4-D and COD herbicides were obtained during HRT of 24 h, and the filling ratio of 70% were 97.33% and 88.95%, respectively. The consortium of 2,4-D degrading bacteria identified in this study included E. coli, Enterobacter spp., Bacillus spp., Alcaligenes spp., Proteus spp., Acinetobacter spp., Pseudomonas spp., Arthrobacter, and Brevundimonas vesicularis. In the MBBR biological process, the reaction kinetics followed the Grau second-order model (R 2 = 0.98). In general, the results showed that the combined process of 3DE with G/ß-PbO2 anode and MBBR biological process has relatively high efficiency in 2,4-D herbicide degradation and can be used as a suitable complementary treatment method in wastewater containing non-degradable compounds such as phenoxy herbicides, e.g., 2,4-D should be used.

Diuron degradation using three-dimensional electro-peroxone (3D/E-peroxone) process in the presence of TiO2/GAC: Application for real wastewater and optimization using RSM-CCD and ANN-GA approaches.

The present study investigates the efficiency of a three-dimensional electro-peroxone (3D/E-peroxone) reactor filled with TiO2-GAC in removing diuron from aqueous solution and in the remediation of real pesticide wastewater. The behavior of the system in terms of the effect of independent variables on diuron was investigated and optimized by RSM-CCD and ANN-GA methods. Both approaches proved to have a very good performance in the modeling of the process and determined the optimum condition of the independent variables as follows: initial pH = 10, applied current = 500 mA, supporting electrolyte = 0.07 M, ozone concentration = 10 mg L-1, and reaction time = 10 min. The 3D/E-peroxone process achieved a synergistic effect in diuron abatement and reduced significantly energy consumption, as compared to its individual components. H2O2 concentration generated in the electrolysis system was notably increased in the presence of TiO2-GAC microparticles. The BOD5/COD ratio of the real pesticide wastewater increased from 0.049 to 0.571 within 90 min treatment. Giving to the considerable enhancement of the biodegradability of the wastewater, this study strongly suggests that the 3D/E-peroxone process can be considered as a promising pretreatment step before a biological treatment process to produce intermediates which are more easily degradable by microorganisms.

Sonophotocatalytic treatment of AB113 dye and real textile wastewater using ZnO/persulfate: Modeling by response surface methodology and artificial neural network.

The present study investigates the synergistic performance of the sonophotolytic-activated ZnO/persulfate (US/UV/ZnO/PS) process in the decolorization of acid blue 113 (AB113) dye from aqueous solution and its feasibility for the treatment of real textile wastewater. Decolorization of AB113 solution was modeled by central composite design-response surface methodology (CCD-RSM) and artificial neural network (ANN) approaches and optimized by CCD-RSM and genetic algorithm (GA) approaches. Statistical metrics indicated that both CCD-RSM and ANN approaches seemed satisfactory. However, the results of statistical fit measures indicated a relative superiority of CCD-RSM as compared to the ANN approach. The results of optimization of the process parameters by CCD-RSM and GA approaches appeared to be similar as follows: pH = 6.1, reaction time = 25 min, US power density = 300 W/L, ZnO = 0.88 g/L and PS = 2.43 mmol/L. The synergistic effect of the hybrid US/UV/ZnO/PS process in comparison with its individual processes (US, UV, ZnO, and PS) was found to be 54.3%. Quenching experiments discovered that and HO are the main oxidizing radicals in a mildly acidic condition of the reaction solution. The removal efficiency of AB113 in the presence of some anions decreased in the order of bicarbonate > sulfate > phosphate > nitrate > chloride. Further, the reusability feasibility of ZnO showed that the ZnO material retained its photocatalytic property after five successive cycles of reusability test, while Zn2+ ion concentration in the reaction solution was measured to be 2.81 mg/L. The findings also indicated that the integrated process application suppresses extremely chemical and electrical costs. The study of the feasibility of the US/UV/ZnO/PS process in the treatment of real textile wastewater was done by determining COD, TOC and BOD5/COD ratio. Results demonstrated that the 96.6 and 97.1% reduction of COD and TOC was achieved after 5 and 7 h reaction time, respectively. The obtained BOD5/COD ratio changed from about 0.15 (for non-treated wastewater) to about 0.61 with increasing reaction time from zero to 90 min. In conclusion, the hybrid US/UV/ZnO/PS system can be proposed as a novel and promising approach to be utilized as a pretreatment technique before a biological treatment process to facilitate the biological treatment of recalcitrant textile wastewater.

The catalytic ozonation of diazinon using nano-MgO@CNT@Gr as a new heterogenous catalyst: the optimization of effective factors by response surface methodology.

In this research, the degradation of the insecticide diazinon was studied using a new hybrid catalyst consisting of magnesium oxide nanoparticles (nano-MgO), carbon nanotubes (CNTs), and graphite (Gr), nano-MgO@CNT@Gr, under various experimental conditions. This study shows the optimization of the nano-MgO@CNT@Gr/O3 process for diazinon degradation in aqueous solutions. Box-Behnken experimental design (BBD) and response surface methodology (RSM) were used to assess and optimize the solo effects and interactions of four variables, pH, catalyst loading, reaction time, and initial diazinon concentration, during the nano-MgO@CNT@Gr/O3 process. Analysis of regression revealed an adequate fit of the experimental results with a quadratic model, with R 2 > 0.91. Following the collection of analysis of variance (ANOVA) results, pH, catalyst loading, and reaction time were seen to have significant positive effects, whereas the concentration of diazinon had a considerable negative impact on diazinon removal via catalytic ozonation. The four variables for maximum diazinon removal were found to be optimum (82.43%) at the following levels: reaction time, 15 min; pH, 10; catalyst dosage, 1.5 g L-1; and diazinon concentration, 10 mg L-1. The degradation of diazinon gave six kinds of by-products. The mechanism of diazinon decomposition was considered on the basis of the identified by-products. According to these results, the nano-MgO@CNT@Gr/O3 process could be an applicable technique for the treatment of diazinon-containing wastewater.

Sono-photo-assisted heterogeneous activation of peroxymonosulfate by Fe/CMK-3 catalyst for the degradation of bisphenol A, optimization with response surface methodology.

The present study examined the removal of bisphenol A (BPA) and total organic carbon (TOC) from aqueous solutions by the Fe/CMK-3 as peroxymonosulfate activator used in the sono-photo-catalytic process. The synthesis of Fe/CMK-3 was carried out using the co-precipitation method, and it was characterized by FTIR, XRD, BET, EDX, and TEM. The results showed that the iron nanoparticles were uniformly embedded in the CMK-3 pores. The effect of factors affecting on the removal of BPA and TOC was evaluated by response surface methodology (RSM) with center composite design (CCD). The analysis of variance of the quadratic model showed that the model is significant (p value < .0001 and R2  > 99.4%) and can be used to optimize the removal efficiency of BPA. Optimization results showed that the highest removal efficiency of BPA (100%) and TOC (80.6%) was achieved in optimum conditions of pH 7.8, catalyst dose 0.33 g/L, PMS dose 3.35 mmol/L, BPA concentration 39.3 mg/L, and 78.5 min. In addition, statistical analysis of the data showed that, in the studied range, the initial concentration of BPA was the most influential factor, followed by pH and PMS dose. Highest catalytic stability of Fe/CMK-3 showed the potential applicability of catalyst in the treatment of BPA-containing solutions. The quenching test showed that sulfate radical was the main responsible for the removal of BPA. The decrease in IOUR value after the 75-min reaction time indicates that this process has a high ability for oxidation of the pollutant and its intermediates. Generally, the observed results suggest that the Fe-CMK-3/UV/US/PMS system can be a promising procedure for the removal of persistent pollutants such as BPA from aqueous media. PRACTITIONER POINTS: Fe/CMK-3 exhibited prominent catalytic activity and high stability for peroxymonosulfate activation. Effective degradation of bisphenol A was achieved in the Fe-CMK-3/UV/US/PMS system. The effect of five factors at five levels and their interactions during the removal of BPA was evaluated by RSM method coupled with central composite design (CCD). The analysis of variance of the quadratic model showed that the model is very significant (p value < .0001) and can be used to optimize the removal efficiency of BPA. The quenching test showed that sulfate radical was the main responsible for the removal of BPA. Reducing IOUR value after the 75-min reaction time indicates that toxicity of the solution was significantly decreased in this system.

The Assessment of Trihalomethanes Concentrations in Drinking Water of Hamadan and Tuyserkan Cities, Western Iran and Its Health Risk on the Exposed Population.

BACKGROUND: The aim of the present study was to calculate and to assess the potential lifetime cancer risks for trihalomethanes from consuming chlorinated drinking water in Hamadan and Tuyserkan cities, western Iran in 2016-2017. STUDY DESIGN: A cross-sectional study. METHODS: Seventy-two water samples were collected from the distribution systems and from the outlet of water treatment plants (WTPs) and the experiments were carried out to determine the desired parameters. All the sampling and measurement methods were according to Standard Methods. The obtained data were analyzed using SPSS software. RESULTS: The mean concentration of total THMs in the summer and winter was 42.75 and 17.75 µg/L, respectively, below the WHO and Iranian standard. The positive correlation was observed between temperature and THMs levels. Moreover, THMs concentration in Shahid Beheshti's WTP was several times lower than in Ekbatan's WTP. Chloroform, the dominant species of THMs, was identified at different sampling points. The highest cancer risk in Hamadan was 1.4×10-5 and 4.8×10-5 for male and female, respectively; and the cancer risk was obtained to be 5.6×10-7-2.26×10-6 in Tuyserkan. CONCLUSION: The drinking water obtained from the studied area is safe in terms of THMs concentration. Nevertheless, the highest cancer risk was higher than the EPA's acceptable level of 10-6.

Optimized synthesis of carbon-doped nano-MgO and its performance study in catalyzed ozonation of humic acid in aqueous solutions: Modeling based on response surface methodology.

This research study focused on the optimization of the synthesis of carbon-doped nano-MgO (C-MgO) and the investigation of its catalytic capacity in a catalytic ozonation process (COP) for the removal of humic acid (HA). Characterization analyses, including SEM, EDX, XRD, BET, and photoluminescence test showed that the C-MgO was successfully synthesized. L8 orthogonal arrays according to the Taguchi methodology optimized the synthesis of the C-MgO as follows: sucrose to MgO ratio = 0.5, sonication time = 15 min, calcination temperature = 400 °C and pH = 10.5. A central composite design based on response surface methodology was employed to optimize and model the COP in the removal of HA. A quadratic polynomial model with p-value < 0.0001 and R2 = 0.9988 showed a better fit to experimental responses. The optimum levels of the studied parameters in the COP based on the predictive model were obtained as follows: pH = 9.5, reaction time = 12 min, catalyst dose = 1 g/L, and HA concentration = 5 mg/L. The HA mineralization was determined to be 86.8% at the 100 min reaction time. Additionally, the COP exhibited 34% synergistic effect and the kinetic rate constant of 0.1898 min-1 in the HA removal. The presence of tert-butanol, methanol, salicylic acid, and some anions did not significantly affect the removal of the HA in the COP. From a practical view, this report indicated that the C-MgO catalyst could be potentially applied in the COP for the treatment of the water having high concentrations of HA substances.

Parameter optimization and degradation mechanism for electrocatalytic degradation of 2,4-diclorophenoxyacetic acid (2,4-D) herbicide by lead dioxide electrodes.

2,4-Dichlorophenoxyacetic acid (2,4-D) is one of the most commonly used herbicides in the world. In this work, the electro-catalytic degradation of 2,4-D herbicide from aqueous solutions was evaluated using three anode electrodes, i.e., lead dioxide coated on stainless steel 316 (SS316/ß-PbO2), lead dioxide coated on a lead bed (Pb/ß-PbO2), and lead dioxide coated on graphite (G/ß-PbO2). The structure and morphology of the prepared electrodes were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The process of herbicide degradation was monitored during constant current electrolysis using cyclic voltammetry (CV). In this study, the experiments were designed based on the central composite design (CCD) and were analyzed and modeled by response surface methodology (RSM) to demonstrate the operational variables and the interactive effect of three independent variables on 3 responses. The effects of parameters including pH (3-11), current density (j = 1-5 mA cm-2) and electrolysis time (20-80 min) were studied. The results showed that, at j = 5 mA cm-2, by increasing the reaction time from 20 to 80 min and decreasing the pH from 11 to 3, the 2,4-D herbicide degradation efficiency using SS316/ß-PbO2, Pb/ß-PbO2 and G/ß-PbO2 anode electrodes was observed to be 60.4, 75.9 and 89.8%, respectively. Moreover, the results showed that the highest COD and TOC removal efficiencies using the G/ß-PbO2 electrode were 83.7 and 78.5%, under the conditions pH = 3, electrolysis time = 80 min and j = 5 mA cm-2, respectively. It was also found that G/ß-PbO2 has lower energy consumption (EC) (5.67 kW h m-3) compared to the two other studied electrodes (SS316/ß-PbO2 and Pb/ß-PbO2). The results showed a good correlation between the experimental values and the predicted values of the quadratic model (P < 0.05). Results revealed that the electrochemical process using the G/ß-PbO2 anode electrode has an acceptable efficiency in the degradation of 2,4-D herbicide and can be used as a proper pretreatment technique to treat wastewater containing resistant pollutants, e.g., phenoxy group herbicides (2,4-D).

Data on corrosive water in the sources and distribution network of drinking water in north of Iran.

This study aimed to determine the parameters of scaling and corrosion potential of drinking water in sources and distribution networks of water supply in two cities of north of Iran. The results of Amlash water sampels analysis in winter revealed that the average values of Langelier, Ryznar, Aggressive, Pockorius, and Larson- skold indices was -1.31, 9.73, 11.5, 9.74 and 0.24, respectively, but, in summer they were -1.51, 10.71, 11.36, 10.72 and 0.25, respectively. For Rudsar, the results of water sampels analysis in winter illustrated that the average values of Langelier, Ryznar, Aggressive, Pockorius, and Larson was -1.12, 9.69, 11.33, 9.19 and 0.16, respectively, while, in summer they were -1.05, 10.04, 11.92, 10.18 and 0.19, respectively. The beneficial of this data is showing the clear image of drinking water quality and can be useful for preventing the economical and safety problems relating to corrosion and scaling of drinking water.

Direct Blue 71 removal from aqueous solution by laccase-mediated system; A dataset.

The removal of Direct Blue 71 (DB71), by laccase (EC 1.10.3.2, p-bezenediol:dioxygen oxidoreductases) enzyme in presence of 2,2'-Azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS), in aqueous solution was investigated. Data on this article focused on the optimizing and modeling of DB71 removal by Response surface method (RSM) based on Box-Behnken design (BBD), through studying the effective variables as follows: ABTS dose (0.05-0.2 mM), Laccase dose (0.05-0.2 U mL-1), and pH (3-7). The results of experimental showed that laccase was able to removal DB71 with removal percentage of 83% at concentration of 50 mg L-1 after 30 min incubation in presence of ABTS 0.2 mM, at temperature 40 °C and pH 5. The Analysis of Variance (ANOVA) for the predicted quadratic model was done and quadratic equation showed significant R-Squared (0.9969), Adjusted R-Squared (0.9914) and Adequate Precision (49.7). The lack of fit is not significant due to p-value prob > F more than 0.05.

Data on modeling of enzymatic elimination of Direct Red 81 using Response Surface Methodology.

In this article, three variables including laccase dose, 2,2'-Azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) dose and pH were used to modeling of Direct Red 81 (DR81) elimination from aqueous solutions by laccase-mediated system. Obtained data indicated that the predicted and experimental values were close for DR81 elimination, and the regression was also able to give a good prediction of response for DR81 elimination (R-Squared = 0.9983). From the experimental, the highest elimination of the DR81 was 95. 5% after 30 min incubation at pH 5, temperature 40 °C, ABTS 0.2 mM, and initial concentration of DR81 50 mg L-1 in the presence of 0.2 U mL-1 of the laccase. The data showed that the laccase can be used as a "green" technology for treating of dyes from aqueous solutions. Data analysis was performed using Design-Expert version 7.0.0 (Stat-Ease, trial version).

Occurrence, distribution, and potential sources of antibiotics pollution in the water-sediment of the northern coastline of the Persian Gulf, Iran.

Occurrence and frequency of six most prescribed antibiotics (tetracycline, norfloxacin, azithromycin, anhydro erythromycin, cephalexin, and amoxicillin) were assessed in three wastewater treatment plants (WWTPs), and in water and sediments of the Persian Gulf at Bushehr coastline, Iran. The antibiotics concentration in the influent and effluent of septic tank (the hospital WWTP), activated sludge (the hospital WWTP), and stabilization pond (municipal WWTP) ranged between 7.89 and 149.63, 13.49-198.47, 6.55-16.37 ng/L, respectively. Conventional treatment resulted in incomplete removal of most of the studied antibiotics. Furthermore, the activated sludge was more effective in terms of antibiotic elimination compared to the stabilization pond or septic tank. The mean concentration of antibiotics ranged 1.21-51.50 ng/L in seawater and 1.40-25.32 ng/g in sediments during summer and winter. Norfloxacin was the dominant detected antibiotic in seawater, sediments, and influent of two hospital WWTPs. Seasonal comparisons showed significant differences for erythromycin and amoxicillin concentrations in seawater. Spatial variation indicated the role of physicochemical properties on distribution of antibiotics in seawater and sediments. The results emphasize the need to pay attention to antibiotic contamination in water and sediments of the Persian Gulf.