Consumption of foods contaminated with heavy metals and their association with cardiovascular disease (CVD) using GAM software (cohort study).

Introduction: Heavy metals can enter the environment and food through industrial activities, acid rain, chemical fertilizers, pesticides, and sewage. A large amount of these metals is dangerous because they tend to bio accumulate. A concern with these metals is the long-term, low-dose exposure seen in the general population. HMs can cause disorders in the cardiovascular system through various mechanisms such as the production of free radicals, DNA damage, lipid peroxidation, and oxidative stress. Material and method: Food items measured in the present study included rice, bread, and vegetables. 210 participants (105 controls and 105 patients) were randomly selected for this study. The demographic information of the subjects was obtained from the Hoveyzeh Cohort Center. The relationship between heavy metals in food and cardiovascular diseases is investigated by The Generalized Additive Model (GAM). Result: The results of the present study showed that when urine Cd was smoothed based on rice Cd, there was a significant correlation between urine Cd and Cd consumed in vegetables and rice. The GAM coefficient for urinary Cd excreted in case-control groups and Cd consumed in vegetables were 479.79(SE: 6.49-73.87) and 818.56(SE: 11.96-68.43), respectively, and for rice consumed, it was 0.03(SE: 0.015-2.103) and 0.04(SE: 0.017-2.338), respectively. The GAM coefficient for As consumption in vegetables and As in urine of case and control groups was 1.61 (SE: 9.48-0.16) and 22.36 (SE: 13.60-1.64), respectively. The same coefficient for rice consumption in case and control groups was 4.5 (SE: 0.62-7.22) and 10.48 (SE: 1.46-7.16), respectively. There was a very strong and significant correlation between the Sr in the urine of both groups and the Sr in the food consumed, so that the urinary Sr in the control group is excreted more than in the cardiovascular group. Conclusion: GAM analysis indicates that As in vegetable and rice is more than the standard limitation value. Also, Sr and Cd in vegetables, rice, and bread were more than the standard limitation value. According to the GAM model As had a significant value in rice and vegetables indicating that As is more than the standard limitation value, therefore, it is associated with CVD.

Optimization of the photocatalytic degradation of phenol using superparamagnetic iron oxide (Fe3O4) nanoparticles in aqueous solutions.

The present work was carried out to remove phenol from aqueous medium using a photocatalytic process with superparamagnetic iron oxide nanoparticles (Fe3O4) called SPIONs. The photocatalytic process was optimized using a central composite design based on the response surface methodology. The effects of pH (3-7), UV/SPION nanoparticles ratio (1-3), contact time (30-90 minutes), and initial phenol concentration (20-80 mg L-1) on the photocatalytic process were investigated. The interaction of the process parameters and their optimal conditions were determined using CCD. The statistical data were analyzed using a one-way analysis of variance. We developed a quadratic model using a central composite design to indicate the photocatalyst impact on the decomposition of phenol. There was a close similarity between the empirical values gained for the phenol content and the predicted response values. Considering the design, optimum values of pH, phenol concentration, UV/SPION ratio, and contact time were determined to be 3, 80 mg L-1, 3, and 60 min, respectively; 94.9% of phenol was eliminated under the mentioned conditions. Since high values were obtained for the adjusted R2 (0.9786) and determination coefficient (R2 = 0.9875), the response surface methodology can describe the phenol removal by the use of the photocatalytic process. According to the one-way analysis of variance results, the quadratic model obtained by RSM is statistically significant for removing phenol. The recyclability of 92% after four consecutive cycles indicates the excellent stability of the photocatalyst for practical applications. Our research findings indicate that it is possible to employ response surface methodology as a helpful tool to optimize and modify process parameters for maximizing phenol removal from aqueous solutions and photocatalytic processes using SPIONs.

Investigation of the link between the type and concentrations of heavy metals and other elements in blood and urinary stones and their association to the environmental factors and dietary pattern.

BACKGROUND: Kidney and urinary tract stones are among the most common and important health problems, the prevalence of which is increasing nowadays due to a sedentary lifestyle, improper nutrition, destructive habits in fluid consumption, and improper use of medications. One of the causing factors in the formation of urinary stones is heavy metals. These metals present in tiny amounts in the environment and enter the nature and food cycle due to industrial activities and practices that are not compliant with environmental laws. METHODS: In this context, the present case-control study was conducted to determine the concentrations of heavy metals and other urinary stone-forming elements in both blood and urinary stones and investigate their relationship with environmental factors and dietary patterns in people with urinary stones in Ardabil city in 2022. The sampling of blood and urinary stones was done randomly from patients with urinary stones who were admitted to the Urology Clinic of Imam Reza Hospital, Ardabil. ICP-MS was used to measure the concentrations of heavy metals in the samples. The obtained data were analysed by chi-square test, ANOVA test, t-test, and Tukey test. RESULTS: The body mass index (BMI) was 27.39 ± 3.72 in the case group and 26.37 ± 2.95 in the control group. The copper and selenium concentrations in blood and urinary stones were higher than in other metals. There was a significant relationship between the history of kidney stones and the probability of developing kidney stones. Moreover, a meaningful relationship was found between the concentration of lead element and the formation of kidney stones. The results showed a significant difference in the concentration of nickel and copper in people who consumed vegetables on a daily basis with those with different types of kidney stones. CONCLUSION: The comparison amongst the concentration of heavy metals in various kinds of urinary stones showed that the amount of lead metal was higher in calcium phosphate stones than in calcium oxalate stones.

The effect of convalescent plasma on the treatment of COVID-19 patients in Ardabil, Iran.

BACKGROUND: Infection with COVID-19 has resulted in considerable mortality all around the world. This study aimed to investigate the effect of convalescent plasma on the treatment of hospitalized patients with COVID-19 in Imam Khomeini Hospital at Ardabil, Iran. MATERIALS AND METHODS: In this quasi-experimental clinical trial, patients over 18 years of age with polymerase chain reaction-positive COVID-19 were admitted based on the clinical criteria of respiratory distress with hypoxia (O2 saturation <90) and tachypnea (R Relative Risk (RR) >24) with moderate-to-severe lung involvement and in the 1st week of respiratory disease who were not intubated were nonrandomly assigned to two groups: convalescent plasma therapy (CPT) group (197 cases) and control group (200 cases). We used the Chi-square, t-test, Fisher's exact test, and Pearson's correlation coefficient for statistical analysis. RESULTS: Analyses revealed that length of stay in hospital was significantly lower in the CPT group as compared to the control group (P = 0.001). Twenty-four cases (22.0%) in the CPT group and 85 cases (78.0%) in the control group needed intubation. Furthermore, mortality was 17 cases (18.3%) in the CPT group and 76 cases (81.7%) in the control group, the difference of which was also found to be statistically significant (P < 0.05). CONCLUSIONS: It seems that CPT can be used as an alternative treatment at the early stages of COVID-19 to prevent the progress of the disease, reduce the need for intubation and consequently the length of stay in hospital, and finally, decrease mortality.

Health-promoting behaviors in staff and students of Ardabil University of Medical Sciences.

BACKGROUND: The staff of health and dentistry schools can play an important role in encouraging students and their clients to adopt health and preventive behaviors. The aim of this study was to compare health-promoting behaviors in staff and students of health and dental schools in Ardabil University of Medical Sciences (ARUMS). MATERIALS AND METHODS: This cross-sectional descriptive-analytical study was conducted in 2021. The research population was staff and students of health and dental schools. Staff sampling was by census and students were sampled by simple random sampling. The data collection tool was a questionnaire whose validity and reliability had been confirmed in previous studies. Data analysis was performed using descriptive and analytical statistics tests using SPSS version 20 software. Linear regression was performed using stepwise method. RESULTS: The results showed that the mean score of the individuals was 99.2 ± 20.24. In the leveling, the behaviors of 33 people (17.55%) were appropriate, desirable and good, and the health-promoting behaviors, 154 people (82.45%), were moderate and low. The correlation between age, gender, marital status, and workplace of the individuals with health-promoting behaviors was not statistically significant (P > 0.05). The output of stepwise regression analysis showed that the variables were significant and could predict the scores of health-promoting behaviors. CONCLUSIONS: Health-promoting behaviors in <20% of students and staff are desirable, and in more than 80% of them are moderate and poor. Therefore, educational administrators should use these results in curriculum planning to increase health-promoting behaviors of students and staff. The score of health-promoting behaviors is related to the above-mentioned areas, but the relationship may not be linear.

Investigating SARS-CoV-2 RNA in five municipal wastewater treatment plants, hospital wastewater and wastewater collection networks during the COVID-19 pandemic in Ardabil Province, Iran.

Since 2019, the outbreak of coronavirus with acute respiratory symptoms has caused an epidemic worldwide. Transmission of the disease through respiratory droplets was announced as the main mode of transmission in 2020. But in this study, we discussed the method of indirect transmission of the virus through sewage. In this study, effluents related to urban and hospital wastewater treatment plants in 5 regions of Ardabil Province (northwest of Iran) were investigated. In this research, 120 samples were kept in pre-test conditions (temperature -20 degrees Celsius). To identify the viral genome, special primer and chain reaction probe targeting ORF1ab and N (nucleoprotein gene) genes were used. Out of a total of 120 samples, a total of 3 samples were positive. Wastewater epidemiology (WBE) can be considered as a cost-effective method in the diagnosis and prediction of pathogenic agents. And be considered an effective method for decision-making in order to protect the health of citizens.

Identification coronavirus (SARS-CoV-2) and physicochemical qualities in various water sources and the efficiency of water treatment plants in their removal- case study: Northwest region of Iran.

The presence of SARS-CoV-2 virus in water resources and the transmission of diseases caused by it is one of the factors threatening the quality of water resources. This study for the first time concentrates on the presence of SARS-CoV-2 in water resources an urban location. In the present study, the samples were collected from known depth (30-50 cm) of rivers, dams and lakes. In each sample of water collected, different parameters such as residual chlorine, pH (phenol red), turbidity, total dissolved solids and temperature were also measured. Out of 267 samples, two samples were detected to be positive which their Ct values were 34.2 and 35.67. The existence of viable form of this virus in water and wastewater may be associated with issues for providing public health and difficulties in implementation of pandemic control strategies, and this situation can be exacerbated in developing countries that do not have adequate access to sanitation and safe water.

SARS-CoV-2 in municipal wastewater treatment plant, collection network, and hospital wastewater.

The current outbreak of coronavirus disease (COVID-19) has led to creating a public health emergency conditions since 2019. COVID-19, which is caused by SARS-CoV-2, is spread via human-to-human transmission by direct contact or droplets. Through conducting this study, we were looking for detecting SARS-CoV-2 in wastewater produced in Iran country (Ardabil, Nir, Khalkhal, and Kowsar) (wastewater collection network, wastewater treatment plant, and hospital wastewater). In this research, samples (n=76) were collected from influent and effluent of municipal and hospital wastewater treatment plants, and some samples were also collected from Ardabil municipal wastewater manholes. The sampling duration included the white (lower risk of COVID-19) and red (high risk of COVID-19) conditions. Samples were stored at -20 °C for further diagnostic tests. The specific primer and probe real-time reverse transcriptase-polymerase chain reaction (real-time PCR) targeting ORF1ab and N genes (nucleoprotein gene) were applied to detect viral genomes of the SARS-CoV-2 virus in the wastewater samples. Out of 76 samples, a total of 15 samples (19.73%) collected from wastewater in Ardabil province (Ardabil, Nir, Khalkhal, and Kowsar), were positive in terms of SARS-CoV-2. Wastewater epidemiology can facilitate detection of the incidence of pathogens through metropolises, measurement of population prevalence without direct testing, and provision of information to the public health system about the efficiency of intervening efforts. Graphical abstract.

The healthy behaviours and COVID-19 mortality among Iranian women: a case-control study.

BACKGROUND: Women are among the susceptible groups to Coronavirus disease-19 (COVID-19) in Ardabil, north-west of Iran, despite the current global status. The underlying causes of high incidence and fatality rate of women in Ardabil are not fully understood. Hence, this study aimed to investigate the healthy behaviours in women of Ardabil and its relationship with COVID-19 mortality. METHODS: We conducted a case-control study to compare the adherence to health protocols and behaviours with respect to COVID-19 between the infected (261 patients) and healthy (515 persons) women. Health protocols and behaviours such as using mask, gloves, disinfectants, history of travelling and contacting, and attending various gatherings and places during the COVID-19 pandemic along with demographic variables were defined as independent variables, and COVID-19 death rate was defined as the dependent variable. Multivariable logistic regression methods were used to explore the risk factors associated with COVID-19 mortality. RESULTS: Chi-square and Fisher tests showed significant differences between infected and healthy women in terms of history of contact and traveling (p < 0.05), wearing mask (p < 0.001), going to work place (p < 0.001), and attend public gatherings (p = 0.038). Multivariable logistic regression disclosed that the age group over 80 years: 8.97 times (95% CI 2.27-29.85), women with underlying chronic diseases: 4.14 times (95% CI 1.61-10.64), and obese women: 3.01 times (95% CI 1.04-6.03) were more likely to die from COVID-19 than other women. CONCLUSION: Considering the high incidence and mortality rate in Ardabil women due to COVID-19 and the corresponding health behavioural factors, special emphasis should be given to the increase of women awareness on the importance of healthy behaviours, diet, and life-style.

Application of a fluidized three-dimensional electrochemical reactor with Ti/SnO2-Sb/ß-PbO2 anode and granular activated carbon particles for degradation and mineralization of 2,4-dichlorophenol: Process optimization and degradation pathway.

A three-dimensional electrochemical reactor with Ti/SnO2-Sb/ß-PbO2 anode and granular activated carbon (3DER-GAC) particle electrodes were used for degradation of 2,4-dichlorophenol (2,4-DCP). Process modeling and optimization were performed using an orthogonal central composite design (OCCD) and genetic algorithm (GA), respectively. Ti/SnO2-Sb/ß-PbO2 anode was prepared by electrochemical deposition method and then its properties were studied by FESEM, EDX, XRD, Linear sweep voltammetry and accelerated lifetime test techniques. The results showed that lead oxide was precipitated as highly compact pyramidal clusters in the form of ß-PbO2 on the electrode surface. In addition, the prepared anode had high stability (170 h) and oxygen evolution potential (2.32 V). A robust quadratic model (p-value < 0.0001 and R2 > 0.99) was developed to predict the 2,4-DCP removal efficiency in the 3DER-GAC system. Under optimal conditions (pH = 4.98, Na2SO4 concentration = 0.07 M, current density = 35 mA cm-2, GAC amount = 25 g and reaction time = 50 min), the removal efficiency of 2,4-DCP in the 3DER-GAC system and the separate electrochemical degradation process (without GAC particle electrode) were 99.8 and 71%, respectively. At a reaction time of 80 min, the TOC removal efficiencies in the 3DER-GAC and the separate electrochemical degradation system were 100 and 57.5%, respectively. Accordingly, the energy consumed in these two systems was calculated to be 0.81 and 1.57 kWh g-1 TOC, respectively. Based on the results of LC-MS analysis, possible degradation pathways of 2,4-DCP were proposed. Trimerization and ring opening reactions were the two dominant mechanisms in 2,4-DCP degradation.

Investigation of SARS-CoV-2 in hospital indoor air of COVID-19 patients' ward with impinger method.

In December 2019, all nations learnt about the emergence of a pandemic of coronavirus disease (COVID-19), induced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is a member of the ß-coronavirus group. As SARS-CoV-2 has the potentiality of leading to life-threatening respiratory failure, its transmission routes need to be characterized. Yet, the possibility of airborne transmission is still debated. This study was performed to evaluate potential hospital indoor air viral quality in order to detect SARS-COV-2. For this purpose, an impinger method was used to monitor the SARS-COV-2 virus in the air. Thus, 33 samples were collected from 8 different hospital locations. The sampling time was between 50 and 60 min with a sampling flow rate of 28 L/min. Air samples were taken from 2 to 5 m away from the patients' beds. Temperature, relative humidity, and CO2 concentration were 28, 37, and 438 ppm, respectively. The results indicated that air samples which were 2 to 5 m away from the patients' beds were negative for the presence of the virus. According to the obtained results, it is suggested that airborne transmission may not have much effect on this pandemic. However, as the patients with SARS-CoV-2 were hospitalized in rooms with negative air pressure, the results might have been negatively affected. Graphical abstract.

Investigation of SARS-CoV-2 virus on nozzle surfaces of fuel supply stations in North West of Iran.

There are several ways for transmitting the SARS-CoV-2 virus to humans, and one of these ways is the contact with infected surfaces. Fuel stations have been a major concern for people and health experts due to the frequent use of common nozzles. This study was performed to identify the COVID-19 virus in the nozzles of fuel supply stations. In the current research, 25 fuel supply stations along the main street ways were investigated to recognize Coronavirus infection on the surfaces of the nozzles. For each fuel supply station, 4 nozzles were chosen (a total of 100 samples). The sampling was carried out at two periods of time, that is, before and after quarantine restrictions. Swapping was used for surface sampling, and Real-time PCR was used to determine the positive and negative results. The results showed that out of nine fuel supply stations (36 samples of nozzle surfaces), five were positive for the presence of SARS-CoV-2 on the nozzle surfaces before the corona restriction. The results showed that in the conditions after corona restriction, all samples were negative in terms of the presence of SARS-CoV-2 on the surfaces of the nozzles. In spite of the fact that gas stations can be one of the foremost inclined places for the transmission and spread of coronavirus due to the nearness and visit of individuals, but through the observance of health behaviors and implementing some procedures, cutting the transmission chain in gas stations can be facilitated.

Evaluation of masks' internal and external surfaces used by health care workers and patients in coronavirus-2 (SARS-CoV-2) wards.

One of the simplest and most effective individual measures is to wear a mask to prevent the spread of respiratory droplets from carriers to healthy people and patients admitted to corona wards and their staff. This research aimed to investigate the contamination of internal and external surfaces of various masks used by patients and staff with SARS coronavirus, as well as the possibility of airborne transmission in Imam Khomeini Hospital, Ardabil. For this purpose, twenty-five staff members and ten patients participated voluntarily in this cross-sectional study. Sampling was performed using swaps on both sides (inside and outside) of various surgical masks, N-95, and filtering face piece FFP2 through standard methods in compliance with the relevant conditions and from a surface of at least 5 cm2. Next, the collected samples were immediately transferred to a laboratory and analyzed by real-time PCR method to detect the presence of SARS-CoV-2 virus after viral genome extraction. Based on the obtained results, from a total of 30 collected samples (25 of personnel masks plus 5 samples of hospitalized patients' masks). A total of 60 masks were sampled. For every collected sample, the researchers studied both inside and outside of the mask. Upon analyzing the data, it was showed that 6 mask samples were positive for the presence of coronavirus. Nonetheless, all samples taken from both inside and outside of the personnel masks (N-95 and FFP2 types of masks) were negative. Among the 6 positive samples, four cases were related to the internal part, one case to the outer part of the three-layer surgical masks, and one to the outer part of the N-95 masks in hospitalized patients. As masks reduce the concentration of virus particles, they can play an important role in creating immunity.

Evaluation of knowledge and health behavior of University of Medical Sciences students about the prevention of COVID-19.

BACKGROUND: Coronaviruses are a large family of viruses that have symptoms ranging from the common cold to severe respiratory syndromes. OBJECTIVE: The purpose of this study is to provide appropriate strategies to raise knowledge and health behavior of students of the University of Medical Sciences to prevent COVID-19. METHODS: This study was conducted as a cross-sectional and descriptive study, and the online questionnaire was used by random sampling. Our sample size was 360 subjects and the statistical population was the students of the University of Medical Sciences. We used the nonparametric test (Kruskal Wallis, Mann-Whitney U) and (Chi-Square & t-test) for statistical analysis. RESULTS: The test results were statistically significant for students' health behavior (p < 0.01, df -99). The knowledge of women was higher than men (F = 5.32, p < 0.02). CONCLUSION: The results show that the Ministry of Health has acted well in promoting students' knowledge and health-promoting behaviors. Therefore, it is recommended that such research be conducted in the public statistical population.

Investigation of SARS CoV-2 virus in environmental surface.

The prevalent respiratory viruses such as SARS-CoV-2 probably persist for a long time on fomites and environmental surfaces. Some recent studies have detected SARS-CoV-2 RNA on the surface of cell phones, door handles and other items in the inhabited sites of confirmed cases. For the aim of this study, a total of 50 environmental surface samples of SARS-CoV-2 was collected from Imam Khomeini Hospital in Ardabil. Forty-one environmental surface samples were proved negative for SARS-CoV-2 RNA while nine surface samples were positive. Our findings regarding surfaces contaminated with the virus are consistent with the results of recent similar researches as it was revealed that a number of different samples taken from hospital surfaces such as handles, cupboards, light switches, and door handles were positive for the presence of SARS-Cov-2.

Investigating the relationship between occupation and SARS-CoV2.

BACKGROUND: Coronaviruses are a large family of viruses that have symptoms ranging from simple symptoms of colds to severe respiratory syndromes. In December 2019, cases of unknown pneumonia first appeared in Wuhan, China. OBJECTIVE: The purpose of this study was to investigate the relationship between occupation and COVID-19 in the Ardabil Imam Khomeini hospital. METHODS: This research was conducted as a cross-sectional and descriptive study. The questionnaires used in this study included demographic information to obtain the required information such as age, sex, clinical symptoms, underlying disease, type of drug used, smoking, occupation, hours of work, number of daily clients, use of mask or shield, type of working hours, weight and height and body mass index, number family, place of residence, role in the family, presence of an infected person in the family, communication with the suspect, observance or non-observance of health protocols. Our sample size consisted of 774 subjects, all patients at the Ardabil Imam Khomeini Hospital. The subjects were selected randomly. RESULTS: The results of this study showed that the mean age of patients was 56.70 years, with a standard deviation of 18.20 years. Three hundred and sixty participants (46.5%) were female, and 414 (53.5%) were male. In terms of occupation distribution, 317 patients (41%) were housewives. In addition, 57 people (7.4%) were farmers or ranchers. CONCLUSION: In general, it can be concluded that due to severity of infection and threat posed by Coronavirus and the risk of infections between different occupations like the taxi driver and medical staff, it is very important to find out what jobs are in the big threat.

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.

Degradation of azo dye Acid Red 14 (AR14) from aqueous solution using H2 O2 /nZVI and S2 O8 2- /nZVI processes in the presence of UV irradiation.

Azo dyes are mostly toxic and carcinogenic and cause harm to humans and the environment. This study was conducted to investigate the degradation of azo dye acid red 14 (AR14) from aqueous solution using hydrogen peroxide (H2 O2) /nano zerovalent iron (nZVI) and persulfate (S2 O8 2- )/nZVI processes in the presence of ultraviolet (UV) irradiation. This experimental study was carried out in a laboratory-scale batch photoreactor with a useful volume of 1 L. The nZVI was synthesized by the sodium borohydride (NaBH4 ) reduction method. In these processes, the effects of parameters including initial pH, H2 O2 concentration, S2 O8 2- concentration, nZVI dose, concentration of AR14 dye, and reaction time were studied. The results showed that decolorization increased by increasing the nZVI dosage, H2 O2 and S2 O4 2- concentrations, and reaction time, or decreasing dye concentration and pH. However, a too high oxidant concentration (H2 O2 and S2 O4 2- ) could inhibit the degradation. The experimental conditions for degradation of AR14 by UV/S2 O8 2- /nZVI and UV/H2 O2 /nZVI processes were as follows: [H2 O2 ] = 10 mM, [S2 O8 2- ] = 8 mM, AB14 dye = 100 mg/L, pH = 3, and nZVI dose = 0.05 g. Under these conditions, the highest removal efficiencies of AR14, chemical oxygen demand (COD), and total organic carbon (TOC) for the UV/S2 O8 2- /nZVI process were 93.94%, 86.5%, and 81.6%, respectively, while these values were 89.3%, 79.57%, and 72.9% for the UV/H2 O2 /nZVI, respectively. Also, the average oxidation state (AOS) was decreased from 2.93 to 2.14 in the effluent of the UV/S2 O8 2- /nZVI process and from 2.93 to 2.2 for the UV/H2 O2 /nZVI process. The results showed that the ratio of biochemical oxygen demand (BOD5 ) to COD in the effluents of the UV/S2 O8 2 /nZVI and UV/H2 O2 /nZVI processes after 90 min was 0.63 and 0.74, respectively. These findings suggest biodegradability improvement. PRACTITIONER POINTS: Photocatalytic degradation of azo dye Acid Red 14 (AR14) was achieved using H2 O2 /nZVI and S2 O8 2- /nZVI processes in the presence of UV irradiation. Effects of operating parameters on photocatalytic degradation AR14 dye were evaluated in the UV/H2 O2 /nZVI and UV/S2 O8 2- /nZVI processes. Biodegradability and mineralization studies of AR14 dye photocatalytic degradation were performed for the UV/H2 O2 /nZVI and UV/S2 O8 2- /nZVI processes.

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).