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In this study, a new zinc chloride (ZnCl) impregnated activated carbon (Zn-AC) was prepared from oak charcoals as low-cost material and used as adsorbent for tetracycline (TC) adsorption. The Zn-AC was characterized using field emission-scanning electron microscope, powder X-ray diffraction, and CHNS-O analyses. Specific surface area of the adsorbent was also measured using the Brunauer, Emmett and Teller (BET) isotherm model. The TC adsorption onto the Zn-AC was investigated as a function of solution pH, adsorbent dosage, and inorganic cations (Li, K, Mg, Ca, Ni, and Fe) and anions (HCO, NO and SO) that could interfere in the adsorption of TC. The adsorbate solution pH had no considerable effect on TC adsorption. The adsorption of TC onto the adsorbent was relatively fast and reached the equilibrium after about 120 min. The results showed that all studied cations and anions decreased TC adsorption onto the Zn-AC, but this decrease in TC adsorption was strongly significant for Fe and Ni ions. The general order kinetic model and the Redlich-Peterson isotherm model provided the best fit to the experimental data. The maximum amount of TC adsorbed onto the Zn-AC (Q) is 282.06 mg g, indicating this adsorbent is a good adsorbent for the removal of TC from aqueous solutions.

Background: Many organic and inorganic pollutants are discharged by various industries into the water bodies. One of the most important pollutants is dye materials that have adverse effects on human health. Objectives: In this study, Aloe Vera wastes-based activated carbon (AV-AC) was used as a low-cost sorbent for the removal of methylene blue (MB) as a textile dye from liquid medium. Methods: The effect of different parameters such as contact time, pH, adsorbent dosage, and initial dye concentration was investigated on the sorption of MB. The experimental data were examined by various kinetic and isotherm models. Results: The equilibrium was obtained at contact time of 40 minutes. Fitting the experimental data to different kinetics and isotherms models indicated that the experimental data were well fitted by the pseudo-second-order kinetic and Freundlich isotherm models. Conclusions: The maximum adsorption capacity was 129.87 mg/g. Due to low cost and high uptake capacity, Aloe Vera wastes can be considered as one effective sorbent for removal of MB.

Background: Epidemiological studies have illustrated that exposure to atmospheric nitrogen oxides (NO 2 /NO X) is responsible for an increased risk of acute or chronic diseases such as cancer. In this study the health risks associated with nitrogen dioxide (NO 2) were assessed in the city of Kermanshah, the capital of Kermanshah province, Iran. Methods: Data on hourly NO 2 levels that had been measured with the Environ tech model M200 was taken from the Kermanshah Environmental Protection Agency (KEPA). The AirQ2.2.3 model was used to quantify data based on baseline incidence (BI), relative risk (RR), and attributable proportion (AP). The number of cases of cardiovascular mortality (CM), acute myocardial infarction (MI), and hospital admissions for chronic obstructive pulmonary diseases (HACOPD) was estimated. Results: The results of the current study show that there were 33, 16, and 13 cases of CM, acute MI, and HACOPD, respectively, attributable to NO 2 exposure. Furthermore, 26.85% of health impacts occurred on days when NO 2 levels did not exceed 40 µg/m 3. For every 10 µg/m 3 increase in the NO 2 level, the risk of CM, MI, and HACOPD rose about 0.2%, 0.36%, and 0.38%, respectively. Conclusion: In order to reduce the number of cases of mortality and morbidity caused by exposure to NO 2 , several immediate steps should be taken by the government to control emissions from various sources, particularly car exhaust, to reduce the levels of NO 2 in the atmosphere.

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Background: Air emission modeling is used to study how pollutants are spread in the environment and to forecast their emissions rate in different climatic conditions in the study area. Today, air pollution threatens human public health and the environment, and Ahvaz is considered one of the main centers of air pollution in Iran. Objectives: This aim of this study was to evaluate the nitrogen dioxide distribution in Ahvaz by using the software program Screen 3. Materials and Methods: This analytical study was conducted in 2013 in Ahvaz. Data collections were performed by the Ahvaz Department of Environment. After processing the data received (averaging instruction set, coding), the file was converted to an input file for the software program Screen 3. In the next phase, study of the distribution and release of nitrogen dioxide during the year 2013 was modeled using the Screen 3 software. Results: Based on the results of this study, the highest and the lowest nitrogen dioxide concentration were in the Bureau of Meteorology and Head office of ADoE stations, respectively. The maximum concentration of NO 2 , at a height of 45 m, was 20 μg/m 3 .According to the findings of the modeling, examination of the combustion process was observed, and this was caused by the amount of nitrogen dioxide emitted by flue outlets, which was affected by temperature and pressure, fuel flow rates and inlet air temperature. Also, results showed that in most cases emission of air pollutants was towards the southwest. Conclusions: Results of this study showed that the Screen3 software is one of the popular models for estimating the distribution of air pollutants. Nitrogen dioxide emissions are highly regulated in most industrialized regions. Decreased emissions from fuel combustion, the use of scrubbers and filters that absorb pollution can be very useful for reduction and control of nitrogen dioxide emissions.