Showing 19 results for Nitrate
Gr Jahed Khaniki, M Mahdavi, A Ghasri, S Saeednia,
Volume 1, Issue 1 (10-2008)
Abstract
Background and Objectives: Bottled water is a main beverage at many developed and developing countries. It can be polluted with chemical agents. One of these agents is nitrate which affects the safety of bottled and mineral water and cause healthy effects on consumer health. Today&aposs consumption of bottled water get a grate develop, thus infer of the quality of this matter is compulsive for each consumer.
Materials and Methods: A descriptive-analytical and cross- sectional study was done with the aim of determination of nitrate in bottled water available in market of Tehran City in 2007. In this study, 18 samples of six various manufacturers of product were examined.
Results: Results showed that the mean of nitrate is 9.02 mg/L and all samples have nitrate bellow 50 mg/L and they are at the standard level. Also, the results of the examinations have good correspondence with the concentration of nitrate on bottled water labels and according to statistic meaningful relation, was considered.
Conclusion: The nitrate content of these bottled water available in market of Tehran city is located at the level of national and global standards and it can not be a serious problem for health of consumer.
B. Mortazavi, B. Ramavandi, G.r Mousavi,
Volume 3, Issue 1 (4-2010)
Abstract
Background and Objectives: Nowadays nitrate concentrations in surface water and especially in groundwater have increased in many locations in the world. Since nitrates cause many health and environmental concerns, increased nitrate concentrations in groundwater have led to rendered aquifers unusable as water sources. So, as the water demand is still increasing the throughout the world, decreasing the nitrate concentration in drinking water is imperative. Magnesium powder has been determined to be potentially useful for the removal of nitrate in the water environment. This research is aimed at subjecting the kinetics of nitrate chemical reduction by Mgo to an analysis of some factors affecting the chemical denitrification.
Materials and Methods: Nitrate concentrations determined in 220 nm using a spectrophotometer.To determine the performance of nitrate removal by Mg0 powder, double distilled water was used for preparation of reagents and simulation of contaminated water with nitrate.All experiments were triplicate and the averaged results were reported.
Results: Kinetics analysis from batch studies revealed that the denitrification reaction with Mgo powder appeared to be a first-order with respect to substrate and the observed reaction rate constant (kobs). The effects of mixing intensity on the denitrification rate suggest that the denitrification appears to be coupled with oxidative dissolution of magnesium through a largely mass transportlimited surface reaction. Also in the denitrification by Mgo determined that Mgo dose related with kobs ( R2>0/99 )S
Conclusion: In this research was determined that denitrification effectively by Mg0 powder can achieved in a wide range of concentrations under atmospheric conditions and without pH controlling within short reaction time. Denitrification rate was related to some parameters such as contact time, Mgo dosage, mixing rate and initial nitrate concentration.
A.r Rahmani, M Solaimany Aminabad, Gh Asgari, F Barjasteh Askari,
Volume 3, Issue 4 (1-2011)
Abstract
Backgrounds and Objectives: High level of nitrate ion in the water resources cause some health and environmental problems. The aim of this research is to study nitrate removal by Zero-Valent Magnesium (ZVM) and MgCl2-modified pumice from aqueous solutions.
Materials and Methods: The pumice granules were modified by MgCl2 . The removal of nitrate was studied in a batch system. The pH, initial nitrate concentration and sorbent mass parameters and the Langmuir and Freundlich models were studied in the sorption of nitrate onto the pumice. The ZVM was also used in a bach system and the previous parameters were studied.
Results: The removal efficiencies of nitrate by ZVM at the the initial pH of 3, 5 and 7 with controlling the pH were 70%, 40% and 30% ,respectively. These values are much higher than the values of the condition during which the pH was not controled. The nitrate removal efficiency increased by increasing of initial nitrate concentration in a constant molar ratio of Mgo/NO3. The removal efficiencies of nitrate by the modified pumice at the the initial pH of 3, 6.5 and 10 (when pH kept under control) were 49%, 29% and 16%, respectively. By increasing of the initial nitrate concentration the removal efficiency increased. The values of R2 for the Langmuir and Freundlich models were 0.944 and 0.810, respectively. The sorption process Fitted well the Langmuir model with a monolayer sorption capacity of 0.68 mg/g.
Conclusion: The modified pumice had lower efficiency than ZVM in the removal of nitrate ion and its usage is not considerably affected bye the pH in comparison with ZVM. The pH of the solution should be cansiderd as a main controling parameter to get an optimum efficiency in the nitrate-ZVM process.
A.r Mesdaghi Nia, A.h Mahvi, S Naseri, A.a Mohamadi, M Shekarriz, M Alimohamadi,
Volume 4, Issue 3 (10-2011)
Abstract
Background and Objectives: New studies indicate that nitrate concentration in groundwater is increasing in most cities. High concentrations of nitrate in water increase the potential health risk in the community and the environment. In infants, No3 _ is reduced to No2 _, which combines with hemoglobin in the blood to form met hemoglobin leading to blue-tinged blood for babies under six months old in particular ,Namely, so-called ‘‘blue baby syndrome&apos&apos and it also produce carcinogenic compounds . Therefore high nitrate concentration is important. The aim of the present study is removing nitrate from water using zero_valent iron.
Materials and Methods: Analyses were conducted on synthetic samples. These samples were analyzed considering reaction times, pH, initial nitrate and sulfate concentration.
Results: Results showed that at Nitrate with an initial concentration of 200mg L1- after 60 min of reaction at pH(s) 7, 6 and 5 about 67.8%, 72.5 % and 88% was reduced, respectively in concentration of 100 and 300 mgL- (pH=6) the removal efficiency is 60 and 83 percent, respectively. In sodium sulfate and nitrate with concentration of 300, the removal efficiency reached from 72 to 70 percent.
Conclusion: Results show that the initial pH is important to achieve maximum efficiency of nitrate removal. So the lower pH levels increases removal efficiency of nitrate. All of the experiments indicated that removal is the highest in the first 5 min. Generally with an increasing initial nitrate concentration the removal efficiency of nitrate increases.
Omol Banin Naeej, Anoushiravan Mohseni Bandpi, Ahmad Jonidi Jafari, Ali Esrafili, Roshanak Rezaei Kalantary,
Volume 5, Issue 3 (10-2012)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Nitrate is one of the most groundwater pollutants in world.
Reduction of nitrate to nitrite by microorganisms cause serious health hazards.
Nitrate can be eliminated using either adsorbtion or reduction. In this study,
we investigated the adsorption of nitate on zeolite and the feasibility of
removal improvement using supported zero
valent nano iron on zeolite via the reduction process.
Materials and Methods: The study was done in two phases investigation the
zeolite and modified zeolite with zero valent nano iron in nitrate removal from
water. First, we determined the optimum pH and time then the effect of
adsorbent and nitrate concentration was investigated in one factor at the time.
The adsorption isotherm was calculated according to the optimum condition. The
physical characteristics of adsorbents were determined using SEM and TEM.
Results: The morphology investigation of adsorbent showed that the
particle size of supported zero valent nano iron on zeolite was approximately
30-50 nm in diameter. The best conditions were pH 5, contact time of 120 min
and 15 g/L for zeolite, while pH 3, contact time of 50 min and 7.5 g/L for
supported zero valent nano iron on
zeolite. The isotherm equations revealed that nitrate adsorption follows
Langmiur in both cases.
Conclusion: The supported zero
valent nano iron on zeolite could be considered as a high potential adsorbent
for nitrate because it has several adsorbent sites, and Fe
0 as a
function for nitrate reduction.
Saeed Parastar, Simin Nasseri, Amir Hossein Mahvi, Mitra Gholami, Amir Hossein Javadi, Saeedeh Hemmati,
Volume 5, Issue 3 (10-2012)
Abstract
Background and Objectives: Pollution of water resources to nitrate is an
environmental problem in many parts of the world. This problem possibly causes
diseases such as methemoglobinemia, lymphatic system cancer and Leukemia.
Hence, nitrate control and removal from water resources is necessary.
Considering that application of nanomaterials in treatment of environmental pollutants
has become an interesting method, in this research use of Ag-doped TiO2 nanoparticles synthesized through photodeposition produced under UV irradiation
was studied for removal of nitrate from aqueous solutions.
Materials and Methods: Three nitrate concentrations of 20, 50, and 100 mg/L were considered. In order
to determine the effect of Ag-doped TiO2 nanoparticles on nitrate removal, dosages of 0.1, 0.4, 0.8 and 1.2 g/L nanoparticles were
used pH range of 5-9 was also considered. The effect of Ag-doped TiO2 nanoparticles both in darkness and under UV irradiation was studied. Moreover,
the presence of chloride and sulfate anions on the system removal efficiency
was investigated.
Results: The optimum
performance of nitrate removal (95.5%) was obtained using nitrate concentration
of 100 mg/L, in acidic pH and 0.8 g/L Ag-TiO2. Increase of
nanoparticle dosage up to 0.8 g/L, increased the removal efficiency, but for
1.2 g/L dosage of nanoparticles, the removal efficiency decreased. Maximum
reduction performance without nanoparticles, under UV irradiation and under
darkness conditions were 32% and 23.3% , respectively. In addition, we found
that presence of sulfate and chloride anions in aqueous solution reduced
efficiency of nitrate removal.
Conclusion: Results of
this study showed that Ag-doped TiO2 nanoparticles may be
efficiently used for nitrate removal from aqueous solutions.
Hafez Golstanifar, Simin Nasseri, Amir Hossin Mahvi, Mohamad Hadi Dehghani, Anvar Asadi ,
Volume 5, Issue 4 (2-2013)
Abstract
Background and Objectives: The contamination of nitrate (NO3−) in groundwater resources causes two adverse health effects: induction of “blue-baby syndrome” (methemoglobinemia), especially in infants, and the potential formation of carcinogenic nitrosamines. The aim of this research is to investigate nitrate removal from groundwater using alumina nanoparticles and to determine the adsorption isotherms.
Materials and Methods: This analytical-descriptive study was carried out at lab-scale, under batch conditions, and at room-temperature. The structure of alumina nanoparticles was determined using XRD, SEM, and TEM techniques. The concentration of nitrate in the solutions was determined by spectrophotometer at wavelengths of 220 and 275 nm. In addition, we investigated the impact of the important operational parameters including initial dose of Al2O3 (0.06-0.25 g/l), initial concentration of the solution (50- 300 mg/l), contact time (5-60 min), and pH (3-9). Moreover, we used Freundlich and Langmuir isotherm models to calculate equilibrium constant.
Results: It was found that nitrate removal efficiency increased as we increased contact time, initial concentration and pH in batch system. A maximum of 60% nitrate removal was achieved under following conditions: 60 min contact time, pH 5, and initial nitrate concentration of 300 mg/l as N. The obtained results showed that the adsorption of nitrate by Nano-Gamma-Alumina follows Langmuir isotherm equation with a correlation coefficient equal to 0.982.
Conclusion: Overall, our findings showed that the alumina nanoparticles can be used as an effective adsorbent to remove NO3 from aqueous solutions.
Marzieh Razavi, Mosen Saeedi, Ebrahim Jabaari,
Volume 6, Issue 3 (12-2013)
Abstract
Background & Objectives: In this study, treatability of wastewater from a laundry unit was investigated by applying electrocoagulation method in which two pairs of aluminum and iron electrodes were utilized. Electrocoagulation is a noble treatment method suitable for different kinds of wastewater which has been given a considerable attentions by researchers recently. Applying direct current to two or several suitable metallic electrode in a batch reactor containing effluent would result in flocks of metal hydroxide.
Materials & Methods: We studied the effect of different operational parameters such as pH, electrodes distance, intensity of electrical current, and type of electrodes on the treatment efficiencies.
Results: Aluminum electrodes showed better effects on the treatment efficiencies in nitrate and COD removal. Maximum phosphate removal (99.93%)took place at pH=7 using Al electrodes. Whereas, in the case of iron electrode, maximum nitrate and COD removal efficiencies were about 97.60 and 80% at pH=9 and pH=6 respectively. Operational cost analysis showed that the corresponding costs of Al application as an electrode is different from that of iron electrode application.
Conclusion: Although application of both iron and aluminum electrodes lead to obtaining considerable removal phosphate, nitrate and COD, iron electrodes could result in reasonable removals to meet Environmental Standards with lower operational costs.
Behrooz Karimi, Mohamad Sadeg Rajaie, Mohamad Javad Ghanadzadeh, Masome Mashayekhi,
Volume 6, Issue 4 (3-2014)
Abstract
Backgrounds and Objectives: Nowadays, global concerns about nitrate in groundwater and its adverse impact on health have increased. This study aims to evaluate the efficiency of nitrate reduction from aqueous solution through modified Fenton process using Nano scale zero-valent iron. Material and Methods: This research was an experimental study and performed at laboratory scale. Nitrate reduction was conducted by advanced oxidation process of Fe°/FeІІ/FeШ/H2O2 at pH 2-10, contact time 10-90 min, nitrate concentrations of 50-300 mg/L, and the molar ratio of [H2O2]/[Fe] 0.5-5. The effect of adding H2O2, molar ratio of reagents, contact time, and pH on nitrate removal was examined and optimal conditions for each of these parameters were determined. Spectrophotometer Dr/5000 was used to measure nitrate in the effluent. Results: We found that the optimal parameters in our studywere pH 3, the molar ratio [H2O2]/[Fe°] of 0.5, and the contact time 15 min. By applying these conditions, nitrate removal efficiency at the retention time 15 min, initial nitrate concentration of 100 mg/L, iron concentration of 10 mg/L, and pH 4 for FeШ، FeІІ، Fe°، FeІІ/Fe°/H2O2 and FeШ/Fe°/H2O2 was 10.5, 27.6, 36.5, 62.3, and 74% respectively. Conclusion: According to the experimental results, it was determined that modified Fenton process using zero iron nano-particles can reduce nitrate under optimal conditions and this method can be used for the removal of similar compounds.
Samira Akhavan, Hamid Zare Abyaneh, Maryam Bayat Varkeshi,
Volume 7, Issue 2 (10-2014)
Abstract
The objective of this study was to collect all the conducted studies on nitrate concentration in water resources of Iran. To achieve this purpose, the published papers in ISC and ISI journals as well as conferences and seminars were evaluated. The results of this survey showed that 116 studies have been carried out in 26 provinces of Iran. But,there was no published paper in Ilam, Alborz, South Khorasan, Kohgiluyeh and Boyer-Ahmad, and Lorestan provinces. According to these studies, the largest number of studies was performed in Hamadan province (14 cases), Khuzestan, and Mazandaran provinces (10 cases) and the least number of studies was conducted in Ardabil, Bushehr, Qazvin, Qom, and Kermanshah provinces. In Hamadan province, more than 1435 water samples were collected from water resources of this province, which is representative of large number of studies in this region. Maximum nitrate concentration (318 mg/L) was reported in Isfahan province and then in Zahedan city (295 mg/L), Sistan and Baluchestan Province. Based on the reported results in these studies, the nitrate pollution in water resources of Iran is at medium level. In most of the studies, high nitrate concentrations are due to lack of sewage collection network, discharge of urban and industrial sewage to water resources, and agricultural activities, which use high amounts of manure and fertilizer.
E Sadeghi, K Sharafi, A Almasi, M Dayhim, E Azizi, M Ghayebzadeh,
Volume 7, Issue 4 (1-2015)
Abstract
Background and objectives: Nitrate and nitrite threaten the human health. According to recent research works, one of the great sources of exposure to nitrate and nitrite in human diet is vegetables. The aim of this study is to determine the effect of drying and frying processes on nitrate and nitrite levels in abundant vegetables. Materials and methods: In this descriptive – analytical study, 180 vegetable samples were taken randomly from Kermanshah markets. Nitrite and nitrate concentration was determined by Greece- Ilosoay method. Then, freezing and boiling processes were carried out on samples and again, nitrite and nitrate levels were measured. The mean differences were analyzed using ANOVA and SPSS program. Results: the concentrations of nitrate and nitrite were significantly different (p<0.5) in terms of vegetable type, storage process, or consumption. As average, frying and drying process led to increase nitrite and nitrate levels in the vegetables except Garlic chives. Frying process and drying process decreased the nitrite levels by 13 and 52% respectively, while in the case of nitrate, it was 29 and 25% respectively. Conclusion: Reducing nitrite and nitrate levels does not occur in frying and drying processing in vegetables. Therefore, it is essential to study other methods of processing or control of nitrate and nitrite levels in the vegetables. It is crucial to monitor and control the quality of this product and studying other food processing because of the daily intake of vegetables and potential risks of nitrate and nitrite accumulation and its association with some illnesses and gastrointestinal tract cancers. .
T Rajaee, R Rahimi Benmaran, H Jafari,
Volume 7, Issue 4 (1-2015)
Abstract
Background & Objectives: The prediction and quality control of the Karaj River water, as one of the important needed water supply sources of Tehran, possesses great importance. In this study, performance of artificial neural network (ANN), combined wavelet-neural network (WANN), and multi linear regression (MLR) models were evaluated to predict next month nitrate and dissolved oxygen of “Pole Khab” station located in Karaj River. Materials and Methods: A statistical period of 11 years was used for the input of the models. In combined WANN model, the real monthly-observed time series of river discharge (Q) and the quality parameters (nitrate and dissolved oxygen) were analyzed using wavelet analyzer. Then, their completely effective time series were used as ANN input. In addition, the ability of all three models were investigated in order to predict the peak points of time-series that have great importance. The capability of the models was evaluated by coefficient of efficiency (E) and the root mean square error (RMSE). Results: The research findings indicated that the accuracy and the ability of hybrid model of wavelet neural network with the attitude of elimniations of time series noise had beeb better than the other two modes so that hybrid model of Wavelet artificial neural network wase able the improve the rate of RMSE for Nitrate ions in comparison with neural network and multiple linear regression models respectively, amounting to 35.6% and 75.92%, for Dissolved Oxygen ion as much as 40.57% and 60.13%. Conclusion: owing of the high capability wavelet neural network and the elimination of the time series noises in the prediction of quality parameters of river’s water, this model can be convenient and fast way to be proposed for management of water quality resources and assursnce from water quality monitoring results and reduction its costs.
M Jahangiri-Rad, R Nabizadeh, J Nouri, M Yunesian, F Moattar,
Volume 8, Issue 1 (8-2015)
Abstract
Background and Objective: Nitrate is one of the dissolved anions having great health importance in water. Human activities and natural sources are considered as the main roots of nitrate intrusion in to water bodies. The main objective of this paper was to study nitrate removal by packed bed column filled with (PAN)-oxime-nano Fe2O3. Materials and Methods: PAN-oxime-nano Fe2O3 were synthesized and used as an adsorbent in glass column for the removal of nitrate from aqueous solution. Nitrate solution tank was set above the prepared column. The effect of factors, such as flow rate (2, 5, and 7 mL/min) and bed depth (5, 10, and 15 cm) were studied. Results: It was found that the data fit well with Thomas model and breakthrough curve was designed accordingly. The column performed well at lowest flow rate. As the flow rates and time increased, earlier breakthrough was observed. The column breakthrough time (Ce/C0 = 0.05) was reduced from 9 to 4 h, as the flow rates increased from2 to 7 mL/min. Conclusion: fixed-bed using PAN-oxime-nano Fe2O3 exhibited good removal of nitrate. The adsorption studies showed that at longer bed depth, better removal of nitrate would be achieved. Thomas model was suitable for the normal description of breakthrough curve at the experimental condition. The data also were in good agreement with logistic regression.
R.s Hajimirmohammad Ali, H Karyab,
Volume 8, Issue 4 (3-2016)
Abstract
Background and Objective: The concentration of nitrate, factors affecting the balance sheet, and the changes in an aquifer is of utmost importance. Because modeling is an efficient method to predict the concentration of ions in water resources, in this study using lumped-parameter model and Monte Carlo simulation model, the nitrate concentrations in groundwater resources of Qazvin Plain were estimated and analyzed.
Materials and Methods: A total of 19 wells in different climates of saline watershed in Qazvin Plain were selected and entry and exit routes of nitrate to these sources were analyzed using lumped-parameter model. Finally, Monte Carlo simulation was used to determine the probability of the estimated nitrate concentration in aquifer.
Results: Application of lumped-parameter model for a part of a part of groundwater resources in Qazvin Plain watershed predicted the nitrate concentration in the range of 8.12 to 15.94 mg/l. The maximum concentration was estimated in cold-dry climate with 12.8±0.04 mg/L. Moreover, it was found that the difference between the estimated nitrate concentration and factors affecting its concentration in different climates was significant (p<0.05).
Conclusion: Despite the predicted concentrations of nitrate in the study area were in accordance with the Iran national standard for drinking purposes, the cumulative probability of Monte Carlo simulation showed that the possible violation of nitrate from the safe limit of 10 mg/l in the study area is 90% (p = 0.005).
E Hassani Moghaddam, Ar Bazdar, M Shaaban,
Volume 12, Issue 1 (5-2019)
Abstract
Background and Objective: Nitrate is one of the most important factors in determining the quality of vegetables. Today, due to the excessive use of nitrogen fertilizers to accelerate vegetative growth, many vegetables have a high percentage of nitrates in human diet. The purpose of this study was to investigate the concentration of nitrate in four vegetable species cultivated in Poldokhtar and Khorramabad cities.
Materials and Methods: In this research, the nitrate content of four vegetables including Iranian leek, Basil, Mint and Radish (tuber and leaves) cultivated from olericulture field on Khorramabad and Poledokhtare were measured. A 2kg edible portion of vegetables was randomly collected for each species in triplicate and carried out to the laboratory. The nitrate content was measured according to the instructions of the Institute of Water and Soil of Iran. For this purpose, after preparation of the samples, a spectrophotometer was used to measure absorption at 580 nm. The nitrate content in different vegetables was estimated using a standard curve.
Results: The nitrate mean concentration of the studied vegetables from khorramabad city was 27017 mg/kg for Radish tuber, 9500 mg/kg for Basil, 8408 mg/kg for Iranian leek, 98231 mg/kg for Radish leaves and 5450 mg/kg for Mint. The values for the samples taken from Poledokhtare city were 12933 mg/kg for Radish tuber, 9063 mg/kg for Basil, 6708 mg/kg for Iranian leek, 6296 mg/kg for Radish leaves and 5454 mg/kg for Mint (5454 mg/kg). The values were all higher than the recommended doses for consumption. In control field, the nitrate mean concentration were 1586, 1134, 906, 794 and 662 mg/kg for Radish tuber, Basil, Iranian leek, Radish leaves and Mint, respectively. The values were within the range of recommended doses.
Conclusion: The amounts of nitrate measured in 100g of green tissue in Radish tuber, Basil, Iranian leek, Radish leaf and Mint were 7.36, 3.37, 2.74, 2.64, and 1.98 times more than the daily allowance limit, respectively. Given the high nitrate content in the studied vegetables, it is recommended that cautious is taken for consumption of the vegetables and nitrate content of the vegetables produced in Lorestan province in different seasons should be monitored.
K Jafari, N Hafezi Moghaddas, Ar Mazloumi, A Ghazi,
Volume 12, Issue 3 (12-2019)
Abstract
Background and Objective: Groundwater resources are the most valuable resources of each country. Development of agricultural activities in Ardabil plain and over-use of fertilizers and pesticides, improper disposal of municipal sewage and industrial areas are responsible for groundwater pollution. Clean-up of groundwater resources is very difficult and expensive. One of suitable method in preventing groundwater contamination is determination of the vulnerable zones of an aquifer to manage water resources and sustainable development.
Materials and Methods: In this study for determining of vulnerability of aquifer Ardebil, information of 52 observational wells, 43 pumping tests, average of annual precipitation of 8 stations, 45 logs of exploration wells, land use map, topographic map and geological map have been gathered. Then, data layers of groundwater depth (D), Recharge (R), Aquifer media (A), Soil media (S), topography (T), impact of vadose zone (I) and hydraulic conductivity of aquifer (C) were prepared and overlaid based on DRASTIC method in ArcGIS software.
Results: Zoning map of DRASTIC method showed that DRASTIC index varied between 63 to 195 units. Areas with high vulnerability potential were characteristic with shallow depth groundwater, coarse-texture soil, thin soil and gentle topographic slope. Accuracy of the zoning map was evaluated by nitrate concentration map which showed the increase of DRASTIC index with nitrate concentration.
Conclusion: Northwestern and central parts of the Ardabil plain showed high vulnerability. The results of this study could help to reduce the environmental impact of contaminants on groundwater resources of the study area in future.
Akram Fatemi Ghomsheh, Sareh Nezami,
Volume 13, Issue 1 (4-2020)
Abstract
Background and Objective: Much of the nitrate consumption by humans in the daily diet comes from vegetables. The high concentration of nitrate in edible parts of vegetables causes toxicity, anemia for children and nitrous amine production in adults. Nitrous amine may results in cancer. Samples were collected from four main vegetable markets in Kermanshah city in summer 2019 to investigate the concentrations of these compounds in edible vegetables with high consumption.
Materials and Methods: After preparation of the samples in a laboratory, the nitrate were extracted and its concentration was determined by a spectrophotometer at wavelength 410 nm.
Results: The results showed significant differences in nitrate concentrations for the vegetable samples taken from the different markets (p>0.05). The highest concentration of nitrate were observed in the leafy, tuberous, and fruit-bearing vegetables. The highest nitrate concentration among the leafy vegetables was observed in cress with an average of 2052.14 mg/kg Fresh Weight; among tuberous vegetables was potato with an average of 127.01 mg/kg Fresh Weight; and among fruit-bearing vegetables was cucumber with an average of 37.20 mg/kg Fresh Weight.
Conclusion: The nitrate concentrations for celery, and red onion at the Azadi market were higher than the permissible limit, according to the national standard. Also, the nitrate concentrations in sugar beet leave and potato at the Toopkhaneh Market and nitrate concentration in cress at all the markets were higher than the permissible limit. It is recommended that the concentration of nitrate of edible vegetables should be determined at regular time intervals as well as during different seasons.
Reza Nazarpoor, Masumeh Farasati, Abolhasan Fathaabadi, Mohamad Gholizadeh,
Volume 13, Issue 1 (4-2020)
Abstract
Background and Objective: Synthetic wetlands are engineering systems that use natural plants, soils and organisms to purify municipal polluted water and remove nitrate.
Materials and Methods: In this study, three systems were considerd as soil culture, three systems as plant cultivation on floating plates and three other systems without plant and porous bed as. The experiments were done three times within six months. The hydraulic retention times were 1, 3 and 5 days. The experimental design consisted of a factorial split-plot design. The analysis of variance showed that the efficiency of nitrate removal was affected by the type of constructed wetland, HRT, and temperature changes (p≤0.01).
Results: At the HRT of 1 day, the average efficiency of nitrate removal by the soil culture, plant cultivation on floating plates and control were 14.34%, 12.09% and 10.51%, respectively. At the HRT of 3 days, the average efficiencies were 17.62%, 15.76% and 13.54%, respectively. At the HRT of 5 days, the efficiencies were increased and they were 17.75%, 17.66% and 16.08%, respectively.
Conclusion: The results showed that the soil culture were more efficinet in removing nitrate .Also, the Cyperus alternifolius plant has the potential of nitrate phytoremediation.
Zohreh Akbari Jonoush, Abbas Rezaee, Ali Ghaffarinejad,
Volume 15, Issue 2 (8-2022)
Abstract
Background and Objective: This study aimed to provide an effective electro-catalytic system for the simultaneous reduction of nitrate and disinfection of contaminated water by the electro-catalytic performance of Ni-Fe/Fe3O4 cathode.
Materials and Methods: At first, the Ni-Fe electrode was synthesized by the electro-deposition process. Then its physical properties were analyzed by scanning electron microscopy (FESEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, and photoelectron X-ray spectroscopy (XPS). Simultaneous disinfection and reduction of nitrate were performed under the following conditions: 15 mg Fe3O4 nanoparticles, pH 6.5, NaCl 10 mM, 50 mg/L nitrate, 105 CFU/mL and current density 4 mA/cm2.
Results: According to the results obtained in the absence of nitrate, 100 % of Escherichia coli bacteria were disinfected after 12 minutes. In the presence of nitrate, the time of complete disinfection increased to 120 minutes. In the absence of bacteria, 83% of nitrate was removed in 240 minutes, and in the presence of bacteria, the nitrate reduction efficiency increased slightly to 88%. In the nitrate reduction process, nitrite (0.22 mg/L) and ammonium (3.6 mg/L) were produced. In the presence of bacteria, the amounts of nitrite and ammonium produced increased to 0.42 mg/L and 7.3 mg/L.
Conclusion: The results show the outstanding ability of Ni-Fe/Fe3O4 electrode in electro-catalytic reduction of nitrate and disinfection of contaminated water separately and simultaneously with high efficiency and high selectivity to nitrogen.
