فهرست مطالب نویسنده:
esmail ghahramani
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Aims
This study was aimed at the evaluation of heavy metals in the drinking water of the rural area of Divandarreh city and the assessment of carcinogenic and non-carcinogenic health risks.
Materials and MethodsIn the present work, concentration of four heavy metals in drinking water resource in the rural area of Divandarreh County were evaluated. For these aim, the numbers of 29 samples were collected from rural drinking water resources, and the concentration of heavy metals was determined. In addition, carcinogenic and noncarcinogenic risk assessment was conducted in children and adults as target groups.
ResultsThe level of Cd was higher than the WHO drinking water Standard. The average amount of target hazard quotient for heavy metals through ingestion in children and adults were in the order of Cd > Cr > Pb > Ni. The total hazard quotient hazard quotients (HQ ing + HQ derm) in children group was higher than the limit set by the USEPA (hazard index = 1.68), indicating probable noncarcinogenic risk to this group through consumption of water.
ConclusionBased on the obtained data, the carcinogenic risk for all of the heavy metals were higher than the permissible standard. The obtained data can be useful for managers and the water and wastewater department regarding the improvement of drinking water quality.
Keywords: Carcinogenic risk, dermal contact, divandarreh, Monte–Carlo simulation -
Dyes are considered to be important pollutants in different industries (e.g., textile) and contain various organic materials with complicated structures. These compounds are mainly carcinogenic and toxic and less biodegradable when discharged into the environment. The present study aimed to investigate the performance of multi-wall carbon nanotubes (MWCNTs) modified by chitosan and EDTA in the removal of Direct Blue 15 dye from aqueous solutions. MWCNT was synthesized and characterized using the BET, zeta potential, DLS, SEM, and FTIR techniques. The effects of key parameters including pH, adsorbent dose, initial dye concentration, and contact time were also evaluated. The experimental data of the adsorption process were analyzed using the Langmuir and Freundlich models. With the increased contact time, the removal efficiency of the dye improved, while the increased pH, initial dye concentration, and adsorbent dose led to the reduced dye removal efficiency. With the optimum values of pH (=7), contact time (60 min), adsorbent dose (0.5 g/L), and initial dye concentration (60 mg/L), the maximum adsorption capacity was determined to be 114.42 mg/g. According to the results, the adsorption process using the modified MWCNT followed the Langmuir model and pseudo-second-order kinetics.Keywords: Parameter optimization, Adsorption, Modification, Chitosan, EDTA
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Approximately 10-20% of the total dyes in the world is consumed in the textile industry. The present study aimed to investigate the photocatalytic activity of zinc oxide nanoparticles (ZnO) immobilized on synthetic activated carbon in the removal of the acid blue 113 dye from aqueous solutions. This experimental study was conducted in a photo-reactor with the useful volume of one liter. The effects of pH (3, 7, and 9), zinc oxide nanoparticle concentrations (0.1-0.4 mmol/l), concentration of activated carbon modified by zinc oxide nanoparticles (20, 40, 60, 80, and 100 mg/l), and the initial concentration of the dye (20, 40, 60, 80, 100, and 200 mg/l) were assessed. In addition, the kinetics of the reaction were investigated. The results indicated that the optimal conditions for the process were the pH of 3, activated carbon modified by zinc oxide nanoparticle concentration of 100 mg/l, ratio of 0.4 millimole of zinc oxide per gram of activated carbon, and acid blue 113 dye concentration of 100 mg/l, which resulted in the maximum efficacy of 96%. Moreover, removal efficiency using zinc oxide was greater in all the stages compared to removal efficiency using activated carbon. The kinetic rate was also determined, demonstrating that the process followed the first-order kinetics. In addition, the findings indicated that the process had outstanding efficiency in the removal of the acid blue 113 dye. The photocatalysis of nanoparticle oxidation on synthetic activated carbon could be used effectively as an advanced oxidation reaction to remove dyes.Keywords: Photocatalytic Process, Zinc oxide, Synthetic Active Carbon, Acid Blue 113, Aqueous solutions
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Photocatalytic efficiency of molybdenum-doped zinc oxide nanoparticles in treating landfill leachateAmong various techniques available for leachate treatment, nano-photocatalytic-based techniques have been considered as efficient. The photocatalytic leachate treatment using nanoparticles of zinc oxide doped with molybdenum oxide was performed in the presence of sunlight at a laboratory scale. The molybdenum oxide doped ZnO nanoparticles were synthesized. The properties of nanoparticle were analyzed by using FTIR, SEM, and XRD. Then the parameters such as pH (3, 5, 7, 9, & 11), concentration of nanoparticles (0.5, 1, 2 and 3 g/l), concentration of leachate with dilution (1:10, 1:25, 1:50 and 1:100), and contact time (15, 30, 45, 60, 90, & 120 min) were measured to determine the removal of COD and turbidity. The analysis indicated that nanoparticle size was appropriate and acceptable. Electron microscope images also showed that the nanoparticle shape was hexagonal. The optimum value of pH was 5. It was found that increasing the concentration of nanoparticles enhances the efficiency of the process, the concentration of nanoparticles from 0.5 to 2 g/l at 60 min of contact time, and the efficiency from 34.8 to 55.6%, and increasing in contact time decreases the COD and turbidity leachate. Enhancing the initial concentration of leachate reduces the treatment efficiency of landfill leachate.Keywords: doped, Nanoparticles, photocatalyst, Zinc oxide
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Zinc oxide (ZnO) is a promising metal oxide semiconductor with various applications, especially in the photocatalytic destruction of environmental pollutants. However, this nanoparticle has some limitations, such as poor dispersion, aggregation, and a wide energy gap. As such, the doping of metal oxide semiconductor has been strongly recommended. Addition of manganese (Mn) has proven effective in resolving these issues. On the other hand, addition of carbon-based materials (e.g., graphene) could improve the stability and photocatalytic efficiency of ZnO. Graphene oxide acts as an electron- transport and electron-acceptor agent, controlling the charge transfer in the ZnO/graphene nanocomposite interface. The present study aimed to synthesize manganese-doped graphene/ZnO nanocomposites and determine its structural properties. Some techniques were employed to characterize the prepared composites, including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), dynamic light scattering (DLS), and zeta potential analysis. According to the FTIR analysis, the peak in the range of 3467 cm-1 was due to the presence of zinc groups in the graphene structure, and the peak observed at 439 cm-1 also indicated the presence of Mn in the compound. Furthermore, the results of AFM analysis showed that graphene to be a layered sheet with the mean thickness of 1.48 nanometers. The results of the DLS analysis showed the mean diameter of GO-ZnO-Mn to be 37 nanometers, which reduced after graphene modification. According to the findings, addition of Mn and ZnO to graphene could effectively result in doping.Keywords: Graphene, Nanocomposite, Doping
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مقدمه و هدفآب آشامیدنی منبع مهمی از مواد معدنی ضروری برای بدن می باشد که در غلظت های مشخص برای بدن مفید هستند؛ از جمله املاح آب که بر سلامت بدن موثر می باشد فلوراید است که کاهش مقدار آن باعث پوسیدگی دندان می شود. همچنین غلظت بالای آن نیز باعث اختلالات اسکلتی، فلوروزیس، ناراحتی های گوارشی و اختلالات عصبی می شود. با توجه به اینکه آب شرب مهمترین راه ورود فلوراید به بدن می باشد پایش مقدار آن در آب شرب ضروری است لذا هدف از انجام این مطالعه تعیین غلظت فلوراید در روستاهای شهرستان دیواندره در سال 94 و پهنه بندی آن با GIS بود.روش بررسیدر این مطالعه 99 نقطه شامل 59 چاه، 18چشمه و 22 مخزن در 78 روستای شهرستان دیواندره جهت نمونه برداری انتخاب شد. نمونه برداری طی دو فصل سال شامل فصول کم آبی (مهر و آبان ماه) و پر آبی (اواخر فروردین و اردیبهشت ماه) انجام شد. برای انتقال نمونه-های برداشت شده از ظروف پلی اتیلنی استفاده گردید و بعد از انتقال نمونه ها به آزمایشگاه، مقدار فلوراید آن ها با استفاده از دستگاه یون کروماتوگرافی IC (مدل Metrohm 882 compact IC plus ) قرائت شدند.یافته هانتایج حاصله نشان داد 5/40 درصد نمونه های برداشت شده در فصل کم آبی دارای غلظت فلوراید بالاتر از مقدار استاندارد (mg/L 5/1) بوده اند در حالیکه برای نمونه های برداشتی در فصل پرآبی فقط 33 درصد نمونه ها خارج از محدوده استاندارد قرار داشته اند (که از این میزان 8/81 درصد دارای غلظت فلوراید بالاتر از استاندارد و 2/18 درصد کمتر از حد مجاز بوده اند)نتیجه گیرینتایج نشان داد نمونه های آب روستاهای جنوب دیواندره از نظر غلظت یون فلوراید دارای وضعیت مقبول تری هستند. بطور کلی می توان گفت مواجهه با مقادیر بیش از استاندارد فلوراید در روستاهای دیواندره بالا است، البته بر اساس مقدار کمتر از استاندارد فلوراید شایع تر می باشد. با توجه به اینکه رویکرد پهنه بندی کیفی آب با GIS برای نشان دادن نتایج آزمایشات کیفی آب می تواند منجر به درک سریع و سهولت استفاده برای مدیران و افراد غیر متخصص شود، پهنه بندی کیفیت آب سایر شهرها و روستاهای استان کردستان نیز پیشنهاد می شود.کلید واژگان: آب آشامیدنی, فلوراید, GIS, دیواندرهIntroductionGroundwater is the major source of essential minerals that are necessary to human body at specific concentrations; Fluoride is a water mineral that is effective for health and reducing tooth decay. Its high concentration can cause skeletal disorders¡ fluorosis¡ gastrointestinal and neurological disorders¡ too. Drinking water is the main way of getting fluoride¡ so its monitoring is essential. Therefore¡ this study aimed to measure the fluoride concentration of Divandareh County rural drinking and showing using geographic information system.MethodsIn this cross-sectional study¡ 99 points including 59 wells¡ 18 springs and 22 tanks in 78 villages of Divandareh were chosen to measure their fluoride content. Sampling was conducted in the two seasons i.e.¡ dehydration season (October-November) and wet season (late April and May). The sampling was done using polyethylene containers; then transferred to the laboratory and fluoride content measured using ion chromatography (Metrohm 882 compact IC plus model).ResultsThe results showed fluoride concentration for 40.5% water samples of dehydration season is more than the standard level¡ while only 33 percent of samples were out of standard level (81.8% of them was more than the standard and 18.2% was less than the standard).ConclusionThe fluoride concentration in the water sample of south rural of Divandareh were more acceptable. The obtained results suggested potential for excessive fluoride content in drinking water¡ however¡ these study results indicated low fluoride levels were more common. The GIS approach used in this case study suggests a easy to use and quick understand of water quality¡ so attempt to prepare the fluoride map for all Kurdistan province is recommended.Keywords: Drinking water, Fluoride, GIS, Divandareh
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Textile dyeing is considered to be one of the major industrial sources of high rates of organic and aromatic compounds. Conversely, these compounds have become a significant environmental problem. Many methods have been investigated for color removal from dye-containing wastewater. In this research, the efficiency of the electrocoagulation (EC) process with aluminum electrodes in the removal of Reactive Green 19 (RG-19) dye from synthetic solutions was studied. The experiments were conducted in a batch reactor equipped with 4 aluminum electrodes with a volume of 2 l. Dye concentrations were measured (λmax = 630 nm). The effects of operating parameters, such as voltage, reaction time, initial dye concentration, energy consumption, pH, KCl concentration, and inter-electrode distance, on removal efficiency were investigated. The highest removal efficiency of RG-19 was found to be 33.49, 60.32, 72.43, 93.63, and 94.91 percent for initial voltage of 10, 20, 30, 40 and 50 v, respectively, in optimum conditions (pH = 11, KCL concentration = 0.005 M, and distance = 1 cm). The removal was effectively reduced to less than 99.88% when the initial dye concentration increased from 25 to 150 mg/l. In addition, by increasing KCl concentration and decreasing electrode distance, removal efficiency increased considerably. Based on the results, EC process by aluminum electrodes is an efficient and suitable method for reactive dye removal from wastewater.Keywords: Aluminum, Electrodes, Electrocoagulation, Textile Wastewater
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In this study, removal of methylene blue by electro-coagulation method using aluminum and iron electrodes was investigated. The influence of the operating parameters such as contact time, current density, anode type, inter-electrodes distance, initial and final pH and energy consumption rate was determined. Dye removal was increased with increases in solution pH, current density and contact time and then decreased for increase in initial dye concentration and electrodes distance. The results show that the electrochemical method has significant efficiency in removal of methylene blue, higher efficiency was observed for iron (Fe) electrode; namely 100% and 95.78% of dye was removed by iron and aluminum electrode; respectively, after 24 min contact time. For a given current density, the removal efficiency and energy consumption rate showed that iron electrode was superior to aluminum in removal of methylene blue. In the case of iron as anode type, the required energy for complete dye decolorization was 3.8 kWh/m3; for 98% dye removal, the required energy was observed to be 4.3kWh/m3 in the case of aluminum as anode type. In general, complete methylene blue can be removed at operating parameters condition of iron as anode, distance between electrodes of 1cm, solution pH of 9 and current density of 50 A/m2 for 24 min electro-coagulation time.Keywords: Electro, coagulation, Methylene blue, Iron electrode, Aluminum electrode
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BackgroundMany nosocomial infections are transferred by hand contact between personnel. Among basic actions to control such infections is the investigation of hygienic conditions of washing hands with hand washing liquids. In such situations, if the hand washing agents are contaminated with pathogenic agents, they may lead to the development of nosocomial infections..ObjectivesIn this study, we investigated infections in hand washing liquids in public hospital of Sanandaj during 2011..Materials And MethodsThis was a cross-sectional study conducted in public hospitals of Sanandaj. The type and species of microorganisms from 52 samples were examined and diagnosed. Statistical analysis was done using Excel with frequency distribution tables and descriptive tests..ResultsPseudomonas aeruginosa (47.36%) and Staphylococcus epidermidis (26.31%) had the highest frequencies and Escherichia coli (5.26%) had the lowest isolation rate..ConclusionsThe results indicated that the level of contamination at public hospitals of Sanandaj was very high (59.37%). An important finding of this study was the need for appropriate training because we observed liquid containers without lids or with unsuitable lids..Keywords: Nosocomial Infections, Microbial Pollution, Hand Washing Liquids
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Due to carcinogenic and other hazardous effects of nitrate and nitrite this study has been done. The Objective of this study was survey of nitrate and nitrite concentration at well-waters in villages of Sari city in 2008-2009 and comparison them with standard levels. In this study, 152 water samples from 38 rural well-water supply facilities in each year have been surveyed. Nitrate and nitrite ions concentration were determined by DR-5000 spectrophotometer and then results have been analyzed by descriptive and analytical statistical methods using SPSS 16.Result showed nitrate and nitrite average concentrations respectively were 1.42 ± 0.571 and 0.004 ± 0.00141 mg/L in 1386 and their average concentrations were 1.24 ± 0.461 and 0.0081 ±0.0072 mg/L in 1387 respectively.Nitrate and nitrite average concentrations in the experimented samples were less than recommended permissible concentration level of WHO and water quality standard of Iran (10 and 1 mg/L respectively) and had no hygienic threat in region, But wastewater disposal in seepage wells may cause increase of nitrate and nitrite concentrations in the future.Keywords: nitrate, nitrite, sari
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