In this study, nano-TiO 2 particles were synthesized by sol-gel method. The synthesized nanoparticles were characterized by Fourier Transform Infrared (FT-IR), X-ray diffraction (XRD), Transmission electron microscope (TEM) and Brunauer-Emmett-Teller (BET). The results showed that the average size of TiO 2 nanoparticles and their specific surface area were 21.1 nanometer and 55.35 m 2 /gr, respectively. The effects of several variables such as adsorbent weight, pH and contact time on lead ions adsorption were studied in batch experiments and finally the optimum conditions for lead ions adsorption by synthesized nano-TiO 2 were obtained. The results showed that the synthesized nano TiO 2 had a good capacity to adsorb lead ion. The kinetic data were described by pseudo-first and second-order models. Freundlich and Langmuir isotherm models were used for the analysis of equilibrium data, and results showed that the Langmuir model was suitable for describing the equilibrium data of lead ion adsorption by nano TiO 2 . Using the Langmuir isotherm, the maximum sorption capacity of Pb 2+ was estimated to be 7.41 (mg/g) at 25˚C.
Nano-c-Al 2 O 3 adsorbent was synthesized by the novel sol-gel method. The adsorbent was characterized by transmission electron microscope, Fourier transform infrared and X-ray powder diffraction. The effects of several variables such as, adsorbent weight, pH and contact time on adsorption of chromium (Cr 6? ), nickel (Ni 2? ), cadmium (Cd 2? ) and lead (Pb 2? ) ions were studied in batch experiments. The results showed that the synthesized nano-c-Al 2 O 3 had a good capacity to adsorb Cr and Pb. The kinetic data were described with pseudo-first-and pseudo-second-order models. Three isotherm models, namely Freundlich, Langmuir and Tempkin, were used for analysis of equilibrium data, and results showed that Langmuir and Freundlich models were suitable for describing the equilibrium data of Cr
Introduction: People are constantly exposed to radiation from natural and artificial sources of radiation. Radon is one of the natural radiation sources that its concentration in very high in some part of the world. The presence of radon gas in the air can increase the risk of lung cancer. In this study, the level of indoor radon in dwellings of Isfahan city was surveyed. It should be mentioned that an active alpha GUARD instrument was used to measure radon concentration. All of the measurments took place during the winter and spring of 2018. Materials and methods: In the present survey, 51 residential/commercial buildings were considered to radon gas monitoring based on the population distribution on 15 urban areas and the population of each area and technical possibilities. In each residential/commercial buildings, sampling was carried out at different floors of the building. A professional radon monitoring device (Alpha GUARD PQ2000 PRO) was used to measure indoor radon gas con-centration. Results: The Results of measuring were shown that the radon concentration in the residential/commercial buildings varied from 3 to 251 Bq / m3, with a mean value of 28.57 ± 39.38 Bq / m3. The average annual effective dose re-ceived by the residents of the studied area was estimated to be 0.49 mSv. The results showed a significant difference between the average radon concentra-tion in different floors and the different ventilation of the building, higher values in the lower floors and weaker ventilation. Conclusion: Indoor radon concentration in 4 % of the building was deter-mined to be higher than the limit (100 Bq / m3) recommended by the World Health Organization.
Background: We aimed to investigate the relationship between air pollution and the Infant mortality rate (IMR) during nearly ten years in Tehran, Iran. Methods: This study is a retrospective cohort case using time series analysis. Air pollution monitoring data during the study period (2009-2018) were collected from the information of 23 Air Quality Control Centers in different areas of Tehran. For this purpose, the daily measures of PM10, PM2.5, O3, CO, SO2, NO2 were obtained. Data on infant mortality was obtained from the National Statistics Office of Iran and mortality registered in Tehran's main cemetery during the study period. Distributed lag linear and non-linear models were used. Results: A total of 23,206 infant deaths were reported during the study period. Following an increase of 10 ug/m3 in PM10 in an early day of exposure, the risk of mortality increased significantly (RR=1.003, 95%CI:1.001-1.005). There is a pick on lag 5-10 that shows a very strong and immediate effect of cold temperature which means that cold temperatures increase the risk of mortality at an early time. At cold temperate, (var=0 and lag 0) risk of infant mortality was significantly higher than reference temperature (19˚C) (RR=1.1295, %CI: 1.01-1.25). Conclusion: The results show the adverse effects of PM10 exposure on infant mortality in Tehran, Iran. Accordingly, a steady decline in PM10 levels in Tehran may have greater benefits in reducing the Infant mortality rate.
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