توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱The impact of gasoline ration on air pollution quality in Tehran,Iran
اطلاعات انتشار: اولین کنفرانس مهندسی برنامه ریزی و مدیریت سیستم های محیط زیست، سال
تعداد صفحات: ۸
Tehran has suffered from air pollution for several years. It is now recognized that about 85% or more is due to motor vehicle emissions although progress was made in controlling mobile and stationary sources. The air pollution law was ratified by parliament in 23 April 1995 and then government wrote council prescription of clean air Act program in 1995. PM10 ,CO and NO2 which were measured and converted to pollutant standard index (PSI) during 26 march – 28 july 2006 and the same time in 2007 were gathered. The objective of this study is to show the effects of ration of gasoline on air pollution quality in Tehran.The results showed that carbon monoxide index was decreased % 7.8 but nitrogen dioxide and pm10 index were increased %21.9 and % 3.2 respectively in 26–march –26 july 2007 compare with the same time in 2006 and the difference were statistically significant (Pvalue <0.05). It is conclude able that gasoline ration had effect on air pollution in the first month after this intervention but it's caused an increase for NO2 concentration.<\div>

۲Autohydrogenotrophic denitrification by a bioelectrochemical process: A viability study
اطلاعات انتشار: Iranian Journal of health، اول،شماره۲، Spring ۲۰۱۴، سال
تعداد صفحات: ۶
In this study, viability of the autotrophic bacteria was investigated in a denitrification process. Bench–scale bioelectrochemical denitrification with separated chambers reactor were applied for nitrate reduction from synthetic wastewater. The influences of current density, retention time, mixing on viability of autotrophic denitrifying bacteria were investigated in the bioelectrochemical reactor (BER). It was found that by increasing the current density up to 8 mA\cm2, nitrate reduction rate was increased. At higher current density (24 – 32 mA\cm2), denitrification rate due to excess of hydrogen gas on cathode surface and accumulation of nitrite, was decreased. Low current density (16 mA\cm2) has not had a significant effect on viability of denitrifying bacteria. Mixing of the solution reduced the adverse effects of electric current on bacteria and enhanced the denitrification rate which was mainly due to prevention of bacteria localization, increasing the contact of hydrogen and bacteria, and delay in membrane fouling. The viability of cultivable bacteria has not been significantly influenced by running time.

۳A novel method for recovery of acidic sludge of used–motor oil reprocessing industries to bitumen using bentonite and SBS
اطلاعات انتشار: Iranian Journal of health، اول،شماره۲، Spring ۲۰۱۴، سال
تعداد صفحات: ۸
Acidic sludge is a by–product from used motor oil reprocessing industries, which thousand tons of this sludge are disposed into the environment as a hazardous waste material daily. The acidic sludge contains unsaturated compounds that are polar and asphaltene. The bitumen under certain conditions is produced from mixing of bentonite, polymer styrene – butadiene – styrene (SBS), and acidic sludge.Context and purpose: The objective of this study was the recovery of acidic sludge to bitumen using additives such as bentonite and SBS. Also, the effect of additives with different weight percentages (wt%(on the performance parameters of bitumen was evaluated. At first, spilled oil was separated from the acidic sludge by a centrifugal concentrator. Then, concentrated acidic sludge and additives were mixed in together. Finally, the performance tests were carried out to compare the quality of acidic sludge with the obtained products.The results indicated that performance parameters such as softening point (SP), weight loss, penetration degree, PI, Frass breaking point, and temperature susceptibility (TS) were promoted from 37°C, 1.3%, 230 dmm, –0.07854, –5°C and 0.0451 to 54°C, 1%, 130 dmm, 2.7094, –11°C , 0.02721, respectively. According to the paired sample t–test analysis, a significant difference was found between the bentonite dosage and the improved performance parameters from concentrated acidic sludge and obtained products (pvalue ≤.001). The bentonite and SBS with 2 and 4 wt%, respectively were determined as the suitable additives in the recovery of acidic sludge to bitumen.

۴Development of a novel setup for direct colorimetric visualization of elemental mercury vapor adsorption on colloidal gold nanoparticles (Text in Persian)
اطلاعات انتشار: Iranian Journal of health، اول،شماره۳، Summer ۲۰۱۴، سال
تعداد صفحات: ۶
Mercury is a toxic، persistent، and bio–accumulative pollutant that has adverse effects on environmental and human health. Various studies have been conducted to monitor different forms of mercury. The objective of this study was to develop a novel setup for assessing gas phase elemental mercury vapor adsorption using colloidal gold nanoparticles solutions that display a characteristic surface plasmon resonance absorption peak in the visible spectrum. The UV–VIS–NIR spectrographs of gold nanoparticles blue shifts after exposure to mercury vapor. The surface plasmon resonances (SPR) of ∼4 and ∼30 nm gold nanoparticles were appeared with the sharp peaks at 515 and 528 nm respectively. The mercury vapor adsorbed in gold nanoparticles was related to the size. The amounts of mercury vapor adsorbed per grams of ∼4 and ∼30 nm gold nanoparticles solutions were obtained 1100 µg•g–1 and 1300 µg•g–1 respectively. A proposed novel setup based on UV–Vis spectroscopic undertaken to provide simplicity، use facilitating، potentially inexpensive، and sensitive enough is a suitable system for mercury vapor capture in many fields. It was demonstrated that the amount mercury adsorbed has been related to the sizes of gold nanoparticles. The color change was observed، when elemental mercury vapor adsorbed on the gold nanoparticles.

۵Applying moving bed biofilm reactor for removing linear alkylbenzene sulfonate using synthetic media
اطلاعات انتشار: Iranian Journal of health، دوم،شماره۱، Winter ۲۰۱۵، سال
تعداد صفحات: ۷
Detergents and problems of their attendance into water and wastewater cause varied difficulties such as producing foam, abnormality in the growth of algae, accumulation and dispersion in aqueous environments.One of the reactors was designated with 30% of the media with the similar conditions exactly same as the other which had filling rate about 10 %, in order to compare both of them together. A standard method methylene blue active substance was used to measure anionic surfactant. The concentrations of linear alkylbenzene sulfonate which examined were 50, 100, 200, 300 and 400 mg\l in HRT 72, 24 and 8 hrs.The removal percentage for both of reactors at the beginning of operating at50 mg\l concentration of pollutant had a bit difference and with gradually increasing the pollutant concentration and decreasing Hydraulic retention time, the variation between the removal percentage of both reactors became significant as the reactor that had the filling rate about 30 %, showed better condition than the other reactor with 10 % filling rate. Ideal condition in this experiment was caught at hydraulic retention time about 72 hrs and 200 mg\l pollutants concentration with 99.2% removal by the reactor with 30% filling rate. While the ideal condition for the reactor with 10% filling rate with the same hydraulic retention time and 100 mg\l pollutants concentrations was obtained about 99.4% removal.Regarding anionic surfactant standard in Iran which is 1.5 mg\l for surface water discharge, using this process is suitable for treating municipal wastewater and industrial wastewater which has a range of the pollutant between 100–200 mg\l. but for the industries that produce detergents products which make wastewater containing more than 200 mg\l surfactants, using secondary treatment process for achieving discharge standard is required.

۶Simultaneous Photo–Oxidative Degradation of EDTA and Extro–Oxidative Recovery of Copper from Industrial Effluents
نویسنده(ها):
اطلاعات انتشار: Iranian Journal of Chemistry and Chemical Engineering (IJCCE)، بيست و سوم،شماره۲(پياپي ۳۲)، ۲۰۰۴، سال
تعداد صفحات: ۸
The objectives of this investigation are the studies on the effect of copper ion on photolytic degradation of ethylenediaminetertraaceticacid (EDTA), the effect of EDTA on electrolytic recovery of copper as well as the introduction of a novel combined photolytic and electrolytic cell system for simultaneous recovery of copper and the degradation of EDTA. In this experimental study, a photolytic cell, an electrochemical system, and a combined photolytic –electrochemical (photoelectrolysis) system with and without an activated carbon cathode were used. Analysis was carried out using atomic absorption spectroscopy, and high performance liquid chromatography (HPLC). The results show that a single electrochemical cell can be used to recover copper (82.1% after 9 hours) without achieving complete mineralization of EDTA by anodic oxidation (49.9 % after 9 hours). On the other hand a single photolytic cell can achieve 99.9% degradation of EDTA after 9 hours at pH 3.5 but leaves copper in solution. However, a combined photoelectrolytic system using an activated carbon concentrator cathode achieves a rapid simultaneous degradation of EDTA and recovery of copper. The amount of degradation of EDTA was 99.9% while recovery of copper was 98.8% after 9 hours.
نمایش نتایج ۱ تا ۶ از میان ۶ نتیجه