Ahmad Reza Yari; Behrooz Dezhdar; Alireza Koohpaei; Ali Ebrahimi; Alireza Mashkoori; Mohammad Javad Mohammadi; Shahram Arsang-Jang
Volume 23, Issue 4 , September and October 2016, , Pages 600-607
Abstract
Objectives Noise pollution in urban areas is known as one of the main problems. In order to prevent its damaging effects, it is essential to measure it in towns. This study aimed to determine the noise pollution indicators in Qom, Iran.Methods This cross-sectional study was conducted at selected 12 stations ...
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Objectives Noise pollution in urban areas is known as one of the main problems. In order to prevent its damaging effects, it is essential to measure it in towns. This study aimed to determine the noise pollution indicators in Qom, Iran.Methods This cross-sectional study was conducted at selected 12 stations in the city based on the traffic density. This study was done in autumn and winter 2013. The sound Level was measured by Sound Meter (CEL-320). Also, in each station according to ISO 1996, the equivalent sound level for 15 minutes, was measured for 7 days and 27 times per day. At the same time, passing vehicles were counted. Finally, noise polllution level (NPL) and traffic noise index (TNI) indices were calculated. Data were analyzed using SPSS V18. One-sample t test was used for comparing mean equivalent sound level with standard value. The significant level was considered at 0.05.Results The results showed that the average equivalent sound level in all stations were higher than allowable limit. The maximum and minimum levels were recorded in Motahari Square station as 92.6 dB and Bazaar crossroad as 50.1 dB, respectively (P<0.05). The highest values of TNI and NPL indices were reported for Janbazan station. The level of noise pollution was measured at the highest value in the evening and lowest value in the morning. In addition, results showed that there were significant differences between equivalent sound level and density rate of motor vehicles (P<0.05).Conclusion According to findings, in order to control traffic noise pollution, necessary corrective measures must be considered as soon as possible.
Abdolkazem Neisi; Mehdi Vosoughi; Anvar Asadi; Mohammad Javad Mohammadi; Mohammad Shirmardi; Mehdi Fazlzadeh; Amir Zahedi
Volume 23, Issue 3 , July and August 2016, , Pages 478-489
Abstract
Background Many industries can pollute water quality due to their wastewater discharging into water resources. Textile industries are one of the main sources of water pollution. Due to their high toxicity, wastewaters containing dyes cause many environmental problems. Acidic dyes are one of the main ...
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Background Many industries can pollute water quality due to their wastewater discharging into water resources. Textile industries are one of the main sources of water pollution. Due to their high toxicity, wastewaters containing dyes cause many environmental problems. Acidic dyes are one of the main classes of dyes. In this study, nano-alumina and micro-alumina powder have been used for the adsorption of acid red 14 dye.Materials & Methods This study was carried out in the batch system in laboratory scale. Different parameters such as initial dye concentration, pH, and adsorbent dose were examined. Spectrophotometry (UV/VIS Lambda 25 Perkin Elmer, Shelton) was used to quantify the remaining dyes concentration. Adsorption isotherm and kinetic behaviors of adsorbent for acidic dye removal were studied and fitted to different models.Results The result showed that with increasing the contact time, acid red 14 removal efficiency by micro-alumina and nano-alumina powder and amount of adsorption per mass unit (qe) increased to 18 and 40 mg/L, respectively, and when adsorbent dose increased from 0.2 to 1.2 g/L, qe decreased from 23 to 12 and 47 to 39, respectively. With increasing the pH value in examined range, the removal efficiency decreased from 30 to 6 and 60 to 15 for micro-alumina and nano-alumina powder, respectively. The results of the study of adsorption of acid red 14 by micro-alumina and nano-alumina powder revealed that its kinetics obeyed pseudo-second order (R2>0.99 and 0.98, respectively). The results of present study on adsorption of acid red 14 on micro-alumina and nano-alumina powder revealed that isotherm obeyed Langmuir adsorption (R2 >0.99 and 0.98, respectively). Conclusion The present study showed that the nano-alumina rather than mciro-alumina can be a promising adsorbent for the removal of acidic dyes such as acid red 14.