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A photocatalytic sulfate radical-based advanced oxidation process was studied to degrade 4-chlorophenol (4-CP) using persulfate (PS) catalyzing UV light and heterogeneous catalyst. In this regards, ferroferric oxide nanoparticles anchored on activated carbon (FOC) was applied as a supporter of TiO2 nanoparticles for fabricating of a recoverable photocatalyst (FOCT). Some analysis techniques including PL, UV–vis DRS, XRD, FESEM-EDS, BET, TEM and VSM were utilized to determine the optical, structural, textural and physicochemical characteristics of FOCT. The reaction mechanisms of PS activation and the generation of free radicals were described in details. Moreover, degradation intermediate products were identified and reaction pathway were proposed. It was found that photocatalytic activity and oxidation performance of pure TiO2 were improved after decoration on FOC. An excellent elimination efficiency was achieved in coupling of FOCT and UV irradiation with PS. Over 99 % of 4-CP (60 mg/L) and 49 % of TOC were removed by FOCT/UV/PS at optimum operational conditions. Furthermore, high PCP decontamination rate (> 86 %) was obtained, even at high concentrations (100 mg/L). During consecutive five runs of catalyst use, the degradation rate was decreased slightly to 88 % with a negligible decline in Fe and Ti leaching, demonstrating the excellent reusability and durability of FOCT in oxidation process. SO4 – and HO radicals were detected as main reactive species that involved in the degradation of 4-CP over FOCT/UV/PS system. Thanks to good performance and easy recovery of catalyst, FOCT/UV/PS hybrid system has a great potential for environmental remediation perspectives.

Heavy metals are kind of toxic substances which are abundant in all municipal, agricultural, industrial and treated wastewaters. In this research, a comparative study was carried out for adsorptive removal of Cd2+ from aqueous solution using raw oak waste and NaOH-activated oak waste at different experimental conditions namely, pH of solution (2–8), contact time (5–240 min), adsorbent dosages (0.1–10 g/L) and initial Cd2+ concentrations (25–100 mg/L). In addition, the experimental data of Cd2+ adsorption were fitted with different isotherm and kinetic models to determine the most appropriate model. Artificial neural network (ANN) model was also used to find the effect of each individual parameter on Cd2+ adsorptive removal. Based on the results of batch experiments, adsorbent dosages and initial Cd2+ concentrations had direct and indirect relationships with Cd2+ removal, respectively. Furthermore, among all applied isotherm and kinetic models, Langmuir isotherm model and Avrami fractional-order kinetic models could best-fitted with the experimental data of Cd2+ removal. The results of thermodynamic studies revealed that the adsorption of Cd2+ onto the surfaces of oak waste adsorbents is exothermic and spontaneous. Finally, according to the findings of ANN studies, this approach could model the role of each parameter on Cd2+ removal with high coefficient of correlation (>0.99). Accordingly, pH of solution and temperature had the highest and lowest influence on removal of Cd2+ from solution, respectively. The results implied that oak waste can be selected as a promising and environmentally friendly adsorbent for the effective remediation of water bodies containing heavy metals.

A disastrous outbreak of thunderstorm-induced asthma attacks posed a major public health threat in Ahvaz, Iran in autumn of 2013 (>15,000 referrals to hospital emergency rooms and pulmonary clinics). City officials claimed that promoting factors included acid rain, particulate matter, ozone, and polycyclic aromatic hydrocarbon compounds (PAHS) could lead to this phenomenon. After these potential causes were rejected by careful research, the next possible cause that this study addresses is a potential link of the asthma attacks to airborne pollen grains and fungal spores. In order to sample these parameters, a Hirst-type volumetric spore sampler was used, which was installed on the rooftop of the sampling site. Sampling was done during two six-month periods to characterize the regional bioaerosol. The first period included the autumn (September 22 to December 20 of 2016) and winter seasons (December 21 of 2016 to March 19 of 2017), while the second period included the following autumn (September 23 to December 21 of 2017) and winter seasons (December 22 of 2017 to March 20 of 2018). In both studied periods, airborne weed pollen grains, especially Amaranthaceae sp., were by far the greatest contributor to total airborne pollen grain concentrations (50.45%, 3757 pollen grains/m3 and 52.12%, 2392 pollen grains/m3, respectively). Among fungal spores, Cladosporium had the highest concentrations (75.29%, 258677 spores/m3 and 80.33%, 247693 spores/m3, respectively). Findings also showed that concentrations of airborne pollen grains were higher in autumn seasons (6361 and 4167 pollen grains/m3, respectively) in comparison with winter seasons (1085 and 423 pollen grains/m3, respectively), while the concentrations of fungal spores were enhanced in winter seasons (189216 and 160962 spores/m3, respectively) versus autumn seasons (154377 and 147377 spores/m3, respectively). Fungal spores exhibited a uniform distribution during the entire study period, but airborne pollen grains were significantly higher in autumn seasons. The numbers of referrals associated with thunderstorm asthma attacks decreased drastically after implementing Conocarpus erectus tree pruning activities. We concluded that the autumnal thunderstorm asthma attacks in Ahvaz might be triggered by a combination of bio-allergens (fungal spores and airborne pollen grains such as from Conocarpus erectus) and high levels of air pollutants from industrial activity. The results of this work suggest controlling bio-allergen levels by preventive measures such as tree pruning, weed removal, and emasculating urban green infrastructures before the flowering season.

This study was to investigate the Sonoelectro-activated persulfate oxidation process for petrochemical wastewater treatment. The effects of Sonoelectro-activated persulfate, electro-activated persulfate, Sono-activated persulfate, persulfate, and ultrasound processes for COD removal were determined. The results reveal that the maximum removal efficiency was obtained at pH = 3, ultrasonic power of 300 W, ultrasonic frequency of 130 kHz, potential electrode of 10 V and persulfate concentration of 20 mM. It was observed that the effective removal of COD was 82.31% for the combined system (Sonoelectro-persulfate), 68.97% for electro-persulfate, 21.11% for Sono-persulfate, 13.06% for persulfate and 2.6% for the single ultrasound system, respectively. The highest removal efficiency obtained at 333 K that was 91.2% after 120 min. In addition, the reaction kinetics of COD removal through Sonoelectro-persulfate process fitted well for pseudo-second-order kinetic model with the regression coefficient of 0.89. According to the results, Sonoelectro-activated persulfate oxidation process has been considered as an effective and efficient technique for petrochemical wastewater treatment.

In this study, optimization of adsorptive removal of two cationic (methylene blue (MB)) and anionic (acid red 73 (AR 73)) dyes with modified oak waste (MOW) adsorbent was carried out using response surface methodology (RSM). The input variables included initial solution pH (2–10), contact time (20–200 min), adsorbent dosage (0.5–2.5 g/L) and initial dyes concentrations (10–90 mg/L). Furthermore, the surfaces of the adsorbent were modified with different modifiers to find the most efficient adsorbent. The obtained results of comparative studies on dyes adsorption confirm that sodium hydroxide, compared to other modifiers, has the highest ability to activate the surfaces of the oak waste (OW) to remove dyes from the solution. Using NaOH, the removal efficiency of MB and that of AR 73 were obtained to be 96% and 29%, respectively. In addition, results of the optimization study showed that RSM could significantly predict the experimental data of dyes removal with a high correlation coefficient (0.991 for MB and 0.993 for AR 73). The optimum experimental conditions for dyes removal were pH of 6.2, 160 min contact time, 2.0 g/L adsorbent dosage and 70 mg/L initial dye concentrations. Under this condition, the removal efficiency for MB and AR 73 reached 85.36% and 41.27%, respectively. Ultimately, from the findings of this study, it is observed that MOW can be used as an efficient and cost-effective adsorbent for the removal of dyes from the contaminated aqueous solution.

The aim of this study was to determine the correlation between PM2.5 and NO2 pollutants and oxidative stress marker (8-isoprostane) and lung function tests (FVC and FEV1) in healthy children who were living and studying in three different areas of Ahvaz city including A1: Naderi site with high traffic, A2: Alavi Alley site with average traffic, and A3: Ein 2 site with low traffic (a rural area on the suburb of Ahvaz). 30 students in the 12–13 year-old range were selected from each studied zone (1, 2 and 3 sites) during three months of year. Of each student, one sample was taken every two weeks to measure 8-isoprostane of exhaled breath condensate (EBC). Air pollution data were collected from three air quality monitoring stations. Also, the relationship between air pollution and 8-isoprostane as well as lung function tests were determined using generalized estimating equations (GEE). The mean concentration of PM2.5 and NO2 in A1, A2 and A3 areas were 116, 92 and 45 (μg/m3) also 77, 53 and 14 (ppb) respectively. Among all studied students, there was a significant correlation between the increase of mean concentration of PM2.5 and NO2 in 1–4 before sampling day, increased 8-isoprostane concentration and decreased FEV1, while there was no significant correlation between them and decreased FVC. In A1 site, an increase in IQR (13 μg/m3) PM2.5 and IQR (6.5 ppb) NO2 on 1–4 days before sampling was associated with 0.38 unit (95% CI: 0.11, 0.65) and 1.1 unit (95% CI: 0.85, 1.35) increase in 8-isoprostane concentration, also decreased 121 ml and 190 ml FEV1, respectively. Results showed that the short-term exposure to traffic-related air pollution can decrease the values of lung function indices and increase the oxidative stress. It may adversely affect children’s lungs. Keywords: Air pollution, Lung function, 8-Isoprostane, Traffic, Ahvaz, Iran

This study aimed to survey the concentration of PM10 and heavy metals (cadmium, chromium, cobalt, nickel, lead, and zinc) on normal and dusty days in Ahvaz, Iran. Concentrations of PM10 in a high-traffic area of the city were measured from October 2012 to September 2013 using a high-volume sampler (HVS). Extracted heavy metals were speciated and quantified using Inductivity Coupled Plasma Optical Emission Spectrometry (ICP-OES). The results of this study showed that the average concentration of PM10 in the autumn (October, November, and December), winter (January, February, and March), spring (April, May, and June), and summer (July, August, and September) was 131, 189, 145, and 127 µg/m3 on normal days, respectively. The corresponding values on dusty days were 410, 742, 300, and 278 µg/m3, respectively. The concentrations of the heavy metals during dusty days were higher than those on normal days. The ratio of the overall mean concentration of the heavy metals on dust storm days relative to normal days (D/N ratio) ranged from 1.21 to 2.53. Due to the importance and impacts of PM10 and associated heavy metals on human health, further studies should be conducted to evaluate the concentrations, impacts, and the associated diseases during pollution periods to establish and implement strategies to minimize harmful effects of PM inhalation.

Textile wastewater was treated using an enhanced simultaneous adsorption/oxidation process with magnetic nanoparticles-functionalized carbon (MNPs@C) and H2O2, UV and ultrasonic (US). Both film- and pore-diffusion affect adsorption mechanisms were included in the adsorption process. The dye adsorption was enhanced by oxidative degradation in the present of H2O2 with the suitability in order of UV-Fenton > US-Fenton > Fenton. Catalytic potential of 47% was observed for MNPs@C/H2O2/UV system. For UV-Fenton system 94.8% removal of dye with minimal iron leaching was observed after 5 times of recycle. Increasing catalytic activity of MNPs@C on direct red 16 (DR16) degradation follows the order of PMS > PS > H2O2.

Fermentation of ethanol as a product of sugarcane agro-industry causes the discharge of large amounts of a liquid waste called vinasse into the environment. In this study, co-composting followed by vermicomposting process of the mixtures of vinasse, cow manure, and chopped bagasse was performed for 60 days using earthworms of Eisenia fetida species. The results showed that the trend of changes in C/N was decreasing. The pH of the final fertilizer was in alkaline range (8.1–8.4). The total potassium decreased during the process, ranging from 0.062 to 0.15%, while the total phosphorus increased and its values ranged from 0.06 to 0.10%. The germination index (GI) for all samples was 100%, while the cellular respiration maturity index was 2 g −1 organic carbon day −1 , confirming a very stable compost. The results of this study indicate that the compost obtained from the co-composting-vermicomposting process could be used as a sound soil amendment.

Exposure to air pollutants may be an important environmental risk factor for human health. The main objective of this study was to assess the health impacts of exposure to particulate matter of aerodynamic diameter

This study investigated the photocatalytic activity of synthesized magnetite hydroxyapatite nanoparticles (Fe 3 O 4 @HAP) for the removal of an acid dye. Results of Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD) pattern and scanning electron microscope (SEM) analysis revealed clearly the characteristic bands of HAP groups and Fe 3 O 4 , the crystalline structure, and the surface morphology of this nanostructured catalyst, respectively. According to the batch experiments, increasing the Fe 3 O 4 @HAP dose could successfully develop the photocatalytic activity of Acid Red73 (AR73). Accordingly, the degradation efficiency of AR73 was achieved around 97% under the optimal conditions of UV irradation for 1 h, a good photocatalytic activity. However, this performance was not high in real environment (64% removal of AR73). The results obtained from the chemical oxygen demand (COD) also illustrated that Fe 3 O 4 @HAP had a good performance in decomposing acid dye (93.3% removal of AR73). The pseudo-first-order Langmuir–Hinshelwood model could best describe degradation kinetics in equilibrium conditions which can be used for predicting the degradation rate at different initial concentrations of AR73. The high recoverability of catalyst on AR73 degradation efficiency in sequential cycles indicates the use of the proposed catalyst without any significant effect on the capability of degradation.

This work specially focused on preparation of a magnetic catalyst, carbon impregnated by iron oxide (PAC@Fe3O4), and consider its catalytic ability for the first time in ozonation of high saline petrochemical wastewater (PCW) from PVC and VCM manufacturing industries. The structural and surface properties of the catalyst, the effect of operational factors, biodegradability and mechanisms were also studied in details. Results revealed that the influence of pH on COD removal rate was negligible, whereas process performance was significantly affected by various concentrations of catalyst and ozone. Under the optimum operational conditions, COD and TOC removal reached to 75.3 and 50.3% after 120 min catalytic ozonation, respectively. Organic compounds were also degraded through transformation of ozone into OH both over catalyst surface and in the solution as identified by tert-butanol. A probable comprehensive mechanism include adsorption, homogeneous and heterogeneous catalytic ozonation was also proposed. The biodegradability of PCW was noticeably improved based on the BOD5/COD ratio, AOS and COS indices after 120 min reaction by PAC@Fe3O4/O3 system. The catalyst indicated a weak iron leaching and high catalytic activity upon five recycling cycles, which confirms that it can be reused many times. Therefore, the PAC@Fe3O4/O3 process was an effective and promising technique for successful PCW treatment, due to the efficient reduction of COD, achieve discharge standards and enhance biodegradability.

The limited knowledge about the mechanism of SARS-CoV-2 transmission is a current challenge on a global scale. Among possible transmission routes, air transfer of the virus is thought to be prominent. To investigate this further, measurements were conducted at Razi hospital in Ahvaz, Iran, which was selected to treat COVID-19 severe cases in the Khuzestan province. Passive and active sampling methods were employed and compared with regard to their efficiency for collection of airborne SARS-COV-2 virus particles. Fifty one indoor air samples were collected in two areas, with distances of less than or equal to 1 m (patient room) and more than 3 m away (hallway and nurse station) from patient beds. A simulation method was used to obtain the virus load released by a regularly breathing or coughing individual including a range of microdroplet emissions. Using real-time reverse transcription polymerase chain reaction (RT-PCR), 11.76% (N=6) of all indoor air samples (N=51) collected in the COVID-19 ward tested positive for SARS-CoV-2 virus, including 4 cases in patient rooms and 2 cases in the hallway. Also, 5 of the 6 positive cases were confirmed using active sampling methods with only 1 based on passive sampling. The results support airborne transmission of SARS-CoV-2 bioaerosols in indoor air. Multivariate analysis showed that among 15 parameters studied, the highest correlations with PCR results were obtained for temperature, relative humidity, PM levels, and presence of an air cleaner., Graphical abstract Image 1

Fenton-like catalytic degradation of tetracycline (TC) was studied by using ferro–ferric oxide (Fe 3 O 4 ) nanoparticles coated on activated carbon (AC@Fe 3 O 4 ) which acts as a peroxidase mimetic and persulfate (PS) as a green oxidant. Adsorption and degradation experiments were carried out in a batch system as functions of pH, PS, catalyst and TC concentrations. Kinetic and pathway of TC degradation by AC@Fe 3 O 4 /PS system was also investigated. Under the optimum conditions, the removal efficiency of TC and total organic carbon (TOC) were 99.8 and 50.6%, respectively. AC@Fe 3 O 4 retained its activity and degradation efficiency remained even after five concessive cycles of use.

In the present study, different adsorbents were prepared: activated carbon (AC), MgO and ZnO nanoparticles, and the composite of AC/MgO/ZnO. The AC was prepared from oak charcoals, as low-cost and abundantly available materials in Iran, by chemical activation. MgO and ZnO nanoparticles were synthesized using a sol–gel method. The adsorbents were characterized using Powder X-ray diffraction (XRD), Field Emission-Scanning Electron Microscope (FESEM), and Energy Dispersive X-ray Spectroscopy (EDS). Then, the adsorption behavior of the adsorbents was tested for the removal of atrazine (ATZ) herbicide as a model of organic micro-pollutant. The average crystallite size of MgO and ZnO nanoparticles was calculated from their XRD data using the Scherrer equation. The results showed that the MgO and ZnO nanoparticles had a size in nano scale, which was supported by FESEM images. The experimental data showed that the pH of solution had no considerable effect on the adsorption of ATZ herbicide. The experimental data obtained for the AC and AC/MgO/ZnO composite were fitted to nonlinear pseudo first-order, pseudo-second order, and general order kinetic models. The general order kinetic model provided the best fit to experimental data compared with the other models. The adsorption isotherm data of these two adsorbents at different temperatures fitted well to the Langmuir and Liu models, but followed the Liu isotherm model most precisely, based on the lowest SD value provided by this model. The results of this study indicate that the chemically prepared AC has excellent adsorptive capacity and can be used as an effective adsorbent for the removal of ATZ from aqueous solutions. However, MgO and ZnO nanoparticles exhibited low adsorptive capacity for ATZ and could not be suitable adsorbents for the removal of this pollutant.

The powdered activated carbon impregnated with Fe 3 O 4 magnetic nanoparticles (MNPs) was synthesized by a facile in situ chemical co-precipitation method. The response surface methodology (RSM) with central composite design (CCD) was used to investigate the adsorption properties of phenol and p -chlorophenol (PCP) onto as-synthesized composite. The RSM was also applied to study the main and interactive effects of the parameters (pH, adsorbent dosage, contact time, and initial pollutant concentration) investigated, as well as to obtain the optimum operating conditions for this novel adsorbent. Magnetic powdered activated carbon (MPAC) showed an excellent magnetic response to the magnetic field and was easily separated from the solution. Moreover, the RSM model obtained (R 2 > 0.98) revealed a satisfactory correlation between the experimental results and predicted values of phenol and PCP adsorption. The adsorbent dose was indicated as having the strongest positive influence on adsorption. The identified optimum conditions of adsorption was 6, 118 min, 1.6 g/L and 200 mg/L for pH, contact time, adsorbent dose, and initial phenol and PCP concentration, respectively. The adsorption kinetics fitted well with pseudo-second-order model and the adsorption capacity of phenol and PCP on MPAC inferred from the Langmuir model was 123.45 and 120.48 mg/g, respectively, at 20 °C. In addition, the adsorption activity of MPAC was preserved effectively even after five successive cycles of use owing to its good stability. The thermodynamic parameters indicated that the adsorption of phenol and PCP onto modified PAC was an exothermic and spontaneous process.

Reports on the effects of PM10 from dust storm on lung cells are limited. The main purpose of this study was to investigate the chemical composition and in vitro toxicological impacts of PM10 suspensions, its water-soluble fraction, and the solvent-extractable organics extracted from Middle Eastern Dust storms on the human lung epithelial cell (A549). Samples of dust storms and normal days (PM10200 μg m(-3)) were collected from December 2012 until June 2013 in Ahvaz, the capital of Khuzestan Province in Iran. The chemical composition and cytotoxicity were analyzed by ICP- OES and Lactase Dehydrogenase (LDH) reduction assay, respectively. The results showed that PM10 suspensions, their water-soluble fraction and solvent-extractable organics from both dust storm and normal days caused a decrease in the cell viability and an increase in LDH in supernatant in a dose-response manner. Although samples of normal days showed higher cytotoxicity than those of dust storm at the highest treated dosage, T Test showed no significant difference in cytotoxicity between normal days and dust event days (P value0.05). These results led to the conclusions that dust storm PM10 as well as normal day PM10 could lead to cytotoxicity, and the organic compounds (PAHs) and the insoluble particle-core might be the main contributors to cytotoxicity. Our results showed that cytotoxicity and the risk of PM10 to human lung may be more severe during dust storm than normal days due to inhalation of a higher mass concentration of airborne particles. Further research on PM dangerous fractions and the most responsible components to make cytotoxicity in exposed cells is recommended.

Recently, atrazine has been increasingly used to control weeds in the corn and sugarcane farms, which affects the water resources and aquatic organisms. In this study, atrazine residual concentrations in water and fish samples of the Shadegan wetland (Iran) were investigated. Furthermore, the health and ecological risk assessment were calculated. A total of fifty water samples were collected from the wetland during three periods with a four-month time interval. Also, ten samples of ten different fish species were analyzed at the same time. The estimation of acceptable daily intake and comparison with international standards indicates danger to adjacent residential areas of wetland. Non-carcinogenic risk analysis showed that total hazard quotient (HQing + HQderm) were below the acceptable limit and there is no danger to the residents of the area. Atrazine concentration in the water and fish samples ranged between 0 and 2175.8 μg/L, and 0 to 35.58 μg/L, respectively. Results showed that 88% of the water samples were higher than EPA and WHO guidelines for drinking water in summer. The concentrations of atrazine in fish samples in summer were more than other seasons. Analysis of ecological risk assessment also showed that considering the average atrazine concentration in three seasons, the risk exposure was very high. This study will be beneficial to the both residents and government officials in management of Shadegan wetland pollution in term of toxic compounds.

Constructed wetlands (CWs) are engineered systems that are constructed to mimic natural wetlands. These systems simulate the processes that happen in natural wetlands and remove pollutants from wastewater. CWs have been previously used to treat a wide range of waste streams, including landfill leachate, and they have shown relatively good removal efficiencies. Although the literature on using CWs to treat different waste streams has been previously reviewed, there has been no literature review of constructed wetlands for leachate treatment. This critical analysis of available literature on landfill leachate treatment by CWs will help optimize future research in the field. The primary objective of this article is to present a comprehensive overview of the diverse range of practices, applications and research into the use of CW systems for removing contaminants from landfill leachate. This review of 85 papers across 20 countries focusses on the treatment performance of three different types of CWs (free water surface flow; subsurface flow (horizontal and vertical); and hybrid systems), using data from field- and pilot-scale studies, and discusses the impact of design criteria on CW treatment performance. The reported average % removal efficiencies of BOD5, COD, TP, PO4, Ammonia-N, TKN, TN, and TSS, for Horizontal/Vertical/Hybrid/Free water surface CWs were, respectively: 60.1/79.7/72.2/80.6%; 54.5/59.2/56.2/45.4%; 63.5/46.2/−6.4/5.5%; 67.7/62.1/5.2/−1.6%; 67.2/66.7/68.9/70.0%; 45.4/64.2/64.9/10.6%; 72.1/88.2/67.3/81.7%; and 69.3/55.5/51.8/59.5%.