Papers by Mohammad mahdi Emamjomeh
زمینه و هدف فلزات سنگین شایع ترین آلوده کننده های موجود در پساب های صنعتی هستند. این گونه فلزات د... more زمینه و هدف فلزات سنگین شایع ترین آلوده کننده های موجود در پساب های صنعتی هستند. این گونه فلزات دارای خطرات زیست محیطی بوده و برای سلامت انسان نیز زیان آور هستند. آلودگی آب توسط یون های فلزات سنگین به دلیل خاصیت سمیت و تمایل به تجمع بیولوژیکی یک موضوع مهم زیست محیطی است. لذا مطالعه حاضر با هدف حذف سرب، کادمیم و کبالت از محلول های آبی توسط کیتوزان انجام شده است. مواد و روش: این مطالعه تجربی-تحلیلی در مقیاس آزمایشگاهی انجام شد و نمونه ها به صورت سنتتیک (مصنوعی) تهیه گردید. در این تحقیق تأثیر pH (9 – 3 )، جرم جاذب ( 400 – 100 میلی‌گرم در لیتر)، زمان تماس ( 15، 30، 45، 60 و 90 دقیقه ) وغلظت های اولیه یون های فلزی(200 – 50 میلی‌گرم در لیتر) در حذف یون سرب، کادمیم و کبالت مورد بررسی قرار گرفت. عملکرد فرایند براساس پاسخ های درصد حذف یون های سرب ارزیابی شد. تعیین تعداد آزمایش ها، آنالیز آماری داده ها و بهینه سازی حذف یون سرب، کادمیم و کبالت با به کارگیری طرح مرکب مرکزی و روش سطح - پاسخ انجام شد. نتایج حاصل از جذب در شرایط تعادل، توسط مدل های ایزوترم لانگمیر و فروندلیچ نیز مورد بررسی قرار گرفت. یافته ها: نتایج نشان داد درصد حذف یون سرب، کادمیم و کبالت در شرایط بهینه به ترتیب pH برابر 8، 9/8 و 5/8، زمان واکنش49، 5/24 و 20 دقیقه، غلظت جاذب 397، 6/296 و 385 میلی‌گرم در لیتر، غلظت اولیه فلز سنگین 2/96، 1/50 و 50 میلی‌گرم در لیتر و راندمان حذف سرب، کادمیم و کبالت به ترتیب برابر 89%، 1/99% و 99%9 بدست آمد. در شرایط ذکر شده میزان مطلوبیت مدل برای هرسه فلز برابر با 100% بود. مطابق با نتایج ، مدل هم دمای لانگمیر نسبت به فروندلیچ بهتر می تواند جذب یون های سرب با کیتوزان را پیش بینی کند. همچنین براساس نتایج بیشترین میزان مطابقت سینتیک جذب با مدل شبه درجه دوم مشاهده شد و این مدل به عنوان بهترین نمونه جهت توصیف رفتار سینتیکی جاذب کیتوزان دانه ای در جذب یون سرب، کادمیم و سرب از محیط های آبی انتخاب شد. نتیجه گیری: نتایج به دست آمده نشان داد که کیتوزان جاذب طبیعی مناسبی برای حذف یون سرب، کادمیم و کبالت از محلول های آبی می باشد.همچنین طرح مرکب مرکزی و روش سطح - پاسخ برای بهینه سازی متغیرهای موثر در فرایند حذف یون سرب، کادمیم و کبالت به روش جذب سطحی مناسب است. کلمات کلیدی: کیتوزان، جذب سطحی، یون سرب، یون کادمیم، یون کبالت، محلول های آب
Background: Carbon nanotubes have been considered as dye adsorbent. The colored wastewater must b... more Background: Carbon nanotubes have been considered as dye adsorbent. The colored wastewater must be treated to reduce the environmental risks. Objective: The aim of this study was to determine the efficiency of multi-walled carbon nanotubes for removal of 2-naphthol orange dye from aqueous solutions. Methods: This experimental study was conducted at school of public health affiliated to Yazd University of medical sciences during 2012. The effects of different parameters including detention time, PH value, mixing intensity, the initial concentration of dye, and carbon nanotubes dosage were studied for removal of dye. All experiments were repeated twice and then adsorption isotherms and kinetics of different models were analyzed by comparing the coefficient of determination. Findings: The maximum dye adsorption occurred during the first 30 minutes. The sorption capacity
Journal of Shahrekord University of Medical Sciences, 2015
Iranian journal of public health, 2011
This paper contributes to further exploration of inequity in access to health research capacity d... more This paper contributes to further exploration of inequity in access to health research capacity development by examining the representation of different nations in international public health journals. It also aims to examine the degree of diversity that exists in these journals. This study is a descriptive survey. It was done with objective sampling on 37 ISI health journals on October of 2008. The number and nationality of people in different editorial positions of the journals was identified. The second analysis involved recalculating the numbers obtained for each nation to the population size of nations per million inhabitants. In order to better compare countries in terms of presence in editorial team of the journals, a 'public health editor equity gap ratio' (PHEEGR) was developed. Low income countries have occupied none of the leadership positions of chief editor or associate /assistant chief editors and middle income countries at maximum shared less than 5 percent. T...
Desalination, 2011
Electrocoagulation is a method of applying direct current to sacrificial electrodes that are subm... more Electrocoagulation is a method of applying direct current to sacrificial electrodes that are submerged in an aqueous solution. Dissolving aluminum (Al 3+ ) is predominant in the acidic condition and aluminum hydroxide has tendency soluble. The defluoridation process was found to be ...
Iranian Journal of Health and Environment, 2012
Abstract: Background and Objectives: leachate from municipal solid waste landfill is a strong sew... more Abstract: Background and Objectives: leachate from municipal solid waste landfill is a strong sewage having hazardous toxic substances. It should be treated by choosing a simple, economical, and eco-friendly method. The aim of this study is reduction of COD from the Qom City landfill leachate using electrocoagulation process. Materials and Methods: The experimental study was carried out at bench scale using a batch reactor during 2010. We used a Plexiglas reactor having 0.7 liter capacity, containing nine plate aluminum ...
Question analysis, is a set of methods through which the effectiveness and efficiency of each que... more Question analysis, is a set of methods through which the effectiveness and efficiency of each question and the entire exam questions can be measured. By recognizing the affecting factors, we will be able to design more appropriate and standard exams to increase the efficiency and effectiveness of every single question. Analyzing the questions makes it possible to evaluate the characteristics of each question as well as providing assurance on standard format of questions to be further assessed for expected ability or attributes. The present research was a descriptive study carried out at the School of Public Health (Qazvin University of Medical Sciences) in 2009-2010. A total of 592 questions designed for the final exams of different fields of study including the public health, environmental health, and occupational health were evaluated. Each question was evaluated for its difficulty ratio and distinction ratio to determine the strength and weak points of every single question and t...
Natural organic matter (NOM) affects some qualitative parameters of water such as color. In addit... more Natural organic matter (NOM) affects some qualitative parameters of water such as color. In addition, it can deteriorate the performance of water treatment process including coagulation, adsorption, and membranes. NOM also reacts with chlorine in the chlorination process and may form disinfection by-products. The present study was carried out in laboratory-scale in a batch system using a cylinder shape reactor with effective volume of 2 l. The initial NOM concentrations during the study period were 10, 25, and 50 mg/l. After specific time intervals, samples were taken from the reactor and filtered. Finally, the NOM removal according to total organic carbon (TOC) content of the samples that were analyzed with a TOC analyzer. The results showed that the highest NOM removal efficiency for three initial concentrations 10, 25, and 50 mg/l were 91, 94, and 82%, respectively. These removal efficiencies were obtained at pH 7, contact time of 20 min, and electrical current of 0.1 A. The elec...
Environmental and Health Management of Novel Coronavirus Disease (COVID-19 )
The World Health Organization (WHO) has recently pronounced severe acute respiratory syndrome cor... more The World Health Organization (WHO) has recently pronounced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as a serious pandemic. It is, therefore, mandatory for public health authorities to have an environmental health management plan against COVID-19. This chapter summarizes articles and official reports related to environmental health management and prevention policies against COVID-19. Because medical sectors require comprehensive guidelines to follow in such pandemic situations, this chapter highlights the significant factors of COVID-19 transmission in our environment (e.g., air), waste management for COVID-19, and protection and disinfection policies against COVID-19. At present, scientists are still discovering more about COVID-19 and its effect on the environment and the health sector. As such, further research is required to increase knowledge about the structural and pathogenic features of COVID-19 and to find effective treatments to dominate this epidemic.
DESALINATION AND WATER TREATMENT
In the present study, the treatment of carpet cleaning wastewater was optimized for electrocoagul... more In the present study, the treatment of carpet cleaning wastewater was optimized for electrocoagulation-flotation (ECF) followed sedimentation. In the experimental study, an ECF reactor equipped with four monopolar, parallel-connected aluminum electrodes was utilized. For the optimization, the process variables were selected as methylene blue active substance (MBAS), chemical oxygen demand (COD), and turbidity removal efficiencies, along with the characterization of sludge settling volume at 60 min (SSV 60). For this goal, response surface methodology (RSM) under central composite design (CCD) was employed to optimize the critical factors viz. pH (3.64-10.36), current intensity (0.66-2.34 A), and electrolysis time (9.55-110.45 min). RSM-CCD optimized these key factors to achieve maximum removal efficiencies and minimize SSV 60. Based on the RSM-CCD prediction, the optimum operating conditions were as pH of 5.1, the current intensity of 2 A, and electrolysis time of 53.5 min, in which the obtained model predicted 83.56%, 82.54%, 88.14%, and 226.22 mL/L for MBAS, COD, turbidity, and SSV 60. Correspondingly, the predictions were in agreement with the actual results (85.50%, 84.35%, 90.50%, and 240.17 mL/L, respectively). The operating cost in the optimal conditions was calculated as 0.673 USD/m 3. The results of the study indicated that the electrocoagulation-flotation followed sedimentation was a cost-effective treatment process in removing target pollutants from the carpet cleaning wastewater.
The Journal of Qazvin University of Medical Sciences, 2014
determination. Findings: The maximum dye adsorption occurred during the first 30 minutes. The sor... more determination. Findings: The maximum dye adsorption occurred during the first 30 minutes. The sorption capacity for adsorption of the dye was found to be 2.76 mg/gr. The dye removal efficiency was increased from 87% to 97.2% by decreasing the initial concentration of dye from 100 to 25 mg/l. By increasing the adsorbent dose from 0.05 to 0.4 g/l, the dye removal efficiency was increased from 70.7% to 94.8%. The general order kinetic model provided the best fit to the pseudo-second order kinetic adsorption model and the equilibrium data were best fitted to the Freundlich isotherm model. The maximum efficiency was found to be 97.2%. Conclusion: Multi-walled carbon nanotubes can be effective for removal of 2-naphthol orange dye.
Environmental and Health Management of Novel Coronavirus Disease (COVID-19 )
The Journal of Qazvin University of Medical Sciences, 2017
Background: Exponential growths of population and urbanization, and the development of social eco... more Background: Exponential growths of population and urbanization, and the development of social economy have resulted in an increase in the amount of MSW generation throughout the world. Objective: The present study aimed to survey qualitative and quantitative analysis of solid waste in Shiraz city and comparative these results with the world scenario of solid wastes generation for improving the sustainable management of solid waste. Methods: This cross-sectional study was conducted in 2014 in nine municipality regions Shiraz with a total population of approximately 1,549,354 people. Basic data was gathered through Shiraz waste management organization. Then generation (per capita) and constituent percent of the solid waste were evaluated based on the sampling and field analyzing from reliable guidelines. Data were analyzed with Stata-13 and Excel statistical software. Kolmogorov-Smirnov test used for the normality of variables. Means were compared by Student T test and Mann-Whitney te...
Iranian Journal of Public Health, 2017
Background: Nitrite (NO2−) and nitrate (NO3−) contaminations of groundwater are considered as one... more Background: Nitrite (NO2−) and nitrate (NO3−) contaminations of groundwater are considered as one of the major health challenges in recent decades. This study aimed to evaluate the nitrite and nitrate concentrations in the drinking groundwater of Shiraz, South-central Iran by statistical models. Methods: From 43 active wells of Shiraz drinking water supplies, 344 samples were collected in the high and low precipitation seasons from 2010 to 2014. Nitrate and nitrite concentrations were tested by a DR6000 spectrophotometer, and the results were analyzed by different software, including SPSS ver. 20, ArcView GIS 9.3. It was done by variable and multivariate regression models. In all tests, the level of significance was set at 5%. Results: Nitrate concentrations in the samples were in the range of 5 to 72 mg/l, and 38 (11%) of the samples had nitrate concentrations above the standard level 10 mg/L as nitrogen. The annual mean concentration of nitrite varied from 0 to 0.025 mg/l. There w...
M u ttu cu m a ru S iv a k u m a r , M o h a m m a d. M. E m a m jo m e h 1
In the present study, the treatment of carpet cleaning wastewater was optimized for electrocoagul... more In the present study, the treatment of carpet cleaning wastewater was optimized for electrocoagulation-flotation (ECF) followed sedimentation. In the experimental study, an ECF reactor equipped with four monopolar, parallel-connected aluminum electrodes was utilized. For the optimization, the process variables were selected as methylene blue active substance (MBAS), chemical oxygen demand (COD), and turbidity removal efficiencies, along with the characterization of sludge settling volume at 60 min (SSV60). For this goal, response surface methodology (RSM) under central composite design (CCD) was employed to optimize the critical factors viz. pH (3.64–10.36), current intensity (0.66–2.34 A), and electrolysis time (9.55–110.45 min). RSM-CCD optimized these key factors to achieve maximum removal efficiencies and minimize SSV60. Based on the RSM-CCD prediction, the optimum operating conditions were as pH of 5.1, the current intensity of 2 A, and electrolysis time of 53.5 min, in which t...
Environmental and Health Management of Novel Coronavirus Disease (COVID-19 ), 2021
Since the onset of the COVID-19 pandemic, some countries have had successful experiences as well ... more Since the onset of the COVID-19 pandemic, some countries have had successful experiences as well as failures. Countries have taken significant and different approaches to reducing the spread of COVID-19. This chapter states the soft method and herd immunity policy of some European countries (e.g., Sweden) in the early days of the epidemic, which failed. Most countries (e.g., Italy) that enacted a mandatory lockdown during the epidemic soon realized that this trend should not continue for longer periods because of side effects, namely social and economic troubles. Some other countries (e.g., Germany) imposed a social distancing of two meters in public places, which have been effective in reducing infection. Nowadays, reports indicate that some Asian countries have had more success than most European and American countries in taking containment measures. Hong Kong and Singapore are among the most successful countries in the world since the beginning of the pandemic, while the United S...
Journal of Mazandaran University of Medical Sciences, 2018
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Papers by Mohammad mahdi Emamjomeh