Showing 171 results for Water
A Shahbazi,
Volume 8, Issue 3 (12-2015)
Abstract
Background and Objectives: Rapid growing of Triton X-100 application in industries results in its appearance in effluents and threaten the aqueous ecosystems. Triton X-100 is not biodegradable and can accumulate in food chain.
Materials and Methods: In this study, sorption capacity of six synthesized zeolites with different regular porous structure was studied for triton X-100 (TX-100) surfactant and the results were compared with Clinoptilolite natural zeolite of Damavand region.
Results: Within all zeolite studied, Beta(200) showed the highest sorption capacity (about 575 mg/g), which is due to its regular pore structure with large pore diameter, channel intersections, high SiO2/Al2O3 ratio and high surface area. Langmuir monolayer isotherm and pseudo-second-order kinetic equation could provide well-fitted to the experimental data in simulating adsorption behavior of TX-100 over Beta(200) zeolite.
Conclusion: The adsorption feature was internal sorption and the intraparticle diffusion might be a rate-limiting control for Beta(200) zeolite. Results of experiments demonstrated that the hydrophobic zeolites with large pore diameter such as Beta(200) could be effective sorbents for industrial wastewater treatment features.
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).
B Sepehrnia, R Nabizadeh, A.h Mahvi, S Naseri,
Volume 9, Issue 1 (6-2016)
Abstract
Background and Objective: In this study, WQI was estimated using an Iranian software called IWQIS to assess drinking water quality in Ray Township distribution systems.
Materials and Methods: The assessment of 73 samples of drinking water during 2013 and the comparison of 18 physicochemical parameters with the standard Code of 1053 (Iran National Standard) was done.
Results: The results showed that the concentration of 7 parameters is out of normal range in special percentage of the samples. Those parameters are as follow: total hardness (31.5%), Mg (46.6%), nitrate (50.68%), Na (45.2%), F (42.46%), Cl (2.7%), Sulfate (28.76%) of samples. The medium concentration of theses parameters was: total hardness (375 mg/L), Mg (32 mg/L), Nitrate (47.43 mg/L), Na (187 mg/L), F (0.5 mg/L), Cl (169 mg/L), and Sulfate (263 mg/L). It is estimated that 5.6% of the population of this township are highly exposed to nitrate, 79.1% to fluoride and 13.5% are exposed to sodium. The average WQI in Rey Township in a good spectrum is 71.22.
Conclusion: 17 samples (23.2%) were assessed in excellent spectrum, 54 samples (74%) in good and 1 sample (1.4%) in very poor spectrum and 1 sample in unsuitable condition were assessed. No sample was assessed in poor situation. The samples of the autumn showed the worst quality.
B Ghoreishi, M Shaker Khatibi, H Aslani, A Dolatkhah, A Abdoli Seilabi, M Mosaferi,
Volume 9, Issue 1 (6-2016)
Abstract
Background and Objectives: Qualitative evaluation of sewage sludge before any kind of application is essential. The present study was aimed to investigate Total coliform, Fecal coliform and Salmonella in sewage sludge produced at wastewater treatment plants in Azerbaijan Province, Iran.
Materials and Methods: Nine wastewater treatment plants were chosen in East Azerbaijan Province, and their sludge from drying bed was studied. Total coliforms, thermo-tolerant coliforms, and Salmonella spp., were surveyed during winter time, 2015. Total and thermos-tolerant coliforms were enumerated by EPA method 1680 and salmonella was counted using EPA method 1682.
Results: In the case of total coliform, sludge sample from Jolfa with 1.82×106 MPN/g showed the highest contamination, while Sarab showed lowest fecal coliform count with 2.02×103 MPN/g. As in the case for fecal coliform, the bacteria count for thermo-tolerant coliforms was higher in Jolfa than other cities; on the other hand, Ahar with no fecal coliform count or less than 2.2 showed the minimum contamination rate to fecal coliforms. In case of Salmonella spp., sludge samples from Ahar and Bostan Abad did not show any salmonella. While sludge sample from Tabriz wastewater treatment plant was determined as the most contaminant sludge with bacteria count equal to 84 per g. Moreover, sludge sample from Sarab wastewater treatment plant showed the least contamination rate, and bacteria count was 6 per g.
Conclusion: From the stand point of microbial quality, all sludge samples met class B standards set by USEPA, while none of them could provide class A standards. Thus, special precautions must be taken in case of soil amendments by the sludge produced from wastewater treatment plants.
A Beiki, M Yunesian, R Nabizadeh, R Saeedi, L Sori, M Abtahi,
Volume 9, Issue 1 (6-2016)
Abstract
Background and objectives: Swimming is one of the most popular sport fields and entertainments that has considerable benefits for human health, but on the other hand microbial water contamination in swimming pools through transmission and spread of infectious diseases is a significant threat against public health. In this study, microbial water quality of all public swimming pools in Tehran were assessed and effective factors on microbial water quality were analyzed.
Materials and Methods: This cross-sectional study with the analytical approach was performed in 2013. The whole public swimming pools in Tehran were inspected and water samples were taken for measurement of microbial indicators including thermotolerant coliforms, heterotrophic plate count (HPC), and physicochemical parameters affecting the microbial water quality including turbidity, free residual chlorine and pH and an integrated swimming pool microbial water quality index were used to describe the overall situation. Operational parameters with probable effects on microbial water quality were checked through inspection using a checklist.
Results: The assessment of the swimming pool microbial water quality indicated that the compliance rates of thermotolerant coliforms and HPC were 91.4 and 84.5%, respectively. Compliance rates of free residual chlorine, turbidity, Ph, and temperature were also obtained to be 82.7, 45.5, 85.6, and 65.4% respectively. Based on the integrated swimming pool microbial water quality index, the proportions of swimming pools with excellent and good microbial water quality were 39.6 and 50.4% respectively and the others had not proper microbial water quality. The parameters of water free residual chlorine and turbidity, swimmer density, water recirculation period, dilution amount, cleaning, usage rates of shower and disinfection basin and operation of water treatment systems had significant effects on the microbial indicators (P<0.05).
Conclusion: The study showed that the overall microbial water quality status of public swimming pools in Tehran was acceptable and analysis of the results determined the most efficient interventions for improvement of the microbial water quality of the pools.
M Ahmadee, A Shahidi, Z Ghorbani,
Volume 9, Issue 3 (12-2016)
Abstract
Background and Objective: The role of groundwater has always been an important issue in order to provide drinking water especially in desert areas. However, studies and decision-making on water supply from the water source is more costly and difficult rather than surface water. Therefore, it is important to note the newest methods like zoning. Due to the effects of water chemical parameters on the quality, application of AHP, ANP, FAHP, and FANP methods lead to more accurate results. The aim of this research was to zone groundwater quality using ANP and FANP models and comparison of the results obtained by those achieved, by AHP and FAHP models.
Materials and Methods: For this purpose, the study was conducted to zone groundwater quality in Tabas aquifer located at the east of Iran with latitude between 33˚ 19’-33˚ 50’ and longitude between 60˚ 42’-63˚ 12’. In this study, the parameters studied were Mg, Ca, SO4, Cl, total dissolved solids (TDS), electrical conductivity (EC), and total hardness (TH). Raster maps for each parameter were prepared and these maps were converted to fuzzy maps. Then, the maps were integrated together using the weights from AHP and ANP methods.
Results: The research indicated that the most weighted parameters using ANP method were Cl (0.172), Mg (0.161) and EC (0.159). Cl (0.457), TDS (0.163) and EC (0.141) were the most weighted parameters using AHP methods. In addition, the concentration of each parameter was increased from the east and southeast to the northeast.
Conclusion: Based on the results and groundwater flow path, water quality was reduced due to water flow in aquifer (from the east and southeast to northeast). Hence, the east and the southeast were the best location to provide drinking water. The area of these regions were 22.12, 25.08, 57.35 and 58.24% out of total area as determined using AHP, ANP, FAHP, and FANP, respectively.
Ar Mesdaghinia, S Nasseri, M Hadi,
Volume 9, Issue 3 (12-2016)
Abstract
Background and Objective: Exposure to chemicals such as heavy metals can be occurred through the route of drinking water consumption. Chromium is an important pollutant because of its role in the appearance of carcinogenic and non-carcinogenic health effects in humans. In this study, we studied the carcinogenic risk and non-carcinogenic hazard of chromium due to the consumption of bottled drinking water distributed throughout Iran.
Materials and Methods: The Hazard Quotient (HQ) and Excess Lifetime Cancer Risk (ELCR) indices were calculated. Monte-Carlo simulation technique was adopted for simulating uncertainty in the estimation of HQ and ELCR based on the input variables namely the concentration of pollutant, per capita water consumption, body weight, reference dose, biological availability, and source contribution factors.
Results: The average concentration of chromium in bottled waters determined was 4.79 ± 2.32 µg/L. The amounts of HQ and ELCR for the age groups of lower than 2, 2 to 6, 6 to 16 and over 16 years old were 0.000354, 0.00292, 0.00236, 0.00147 and 4.04×10-11, 5.99×10-10, 8.61×10-10 and 2.34×10-9, respectively.
Conclusion: In regard to the concentration of chromium in bottled waters in Iran, the incidence probability and the possibility of carcinogenic and non-carcinogenic effects by this pollutant due to the consumption of bottled water are considerably low and there is no health concern for any age groups.
S Shakur, Aa Nadiri, A Asghari Moghaddam, M Vadiati,
Volume 9, Issue 3 (12-2016)
Abstract
Background and Objective: Human health depends on clean and safe drinking water more than anything. In Bilverdi Plain, the main source of drinking water is groundwater that has got a low quality in some places. Therefore, the drinking water of this area needs detailed evaluation of quality. In this research, the drinking water of Bilverdi Plain was evaluated based on fuzzy and deterministic methods.
Materials and Methods: Totally, 15 samples were collected from different places in September 2013. Major water ions including fluoride and nitrate of the samples taken were measured at hydrological lab of University of Tabriz. To check the quality of water, Schoeller diagram in GWW environment and MATLAB software in fuzzy inference system were used and their results were compared with each other.
Results: Based on the results in deterministic method, the quality of drinking water was classified ranging from good to undesirable. However, in fuzzy method in addition to water quality, the potability confidence of samples was offered in which water in six samples with reliability percent from 13.8 to 14.7; in five samples with 50% confidence level and in four samples with confidence percent from 73 to 85 were desirable, acceptable and unacceptable respectively.
Conclusion: The results show the higher accuracy and capability of fuzzy method rather than deterministic method. Because it is proper to deal with uncertainty in the different parameters and all effective parameters on water quality could be considered together in the evaluation and it offers confidence level for potability of water.
M Aqanaghad, G Moussavi,
Volume 9, Issue 3 (12-2016)
Abstract
Background and Objective: Being low cost of building and operation, anaerobic baffled reactor is considered superior to aerobic methods of wastewater treatment, especially for small communities. However, it needs to be studded for upgrade and overcome of its limitations. The purpose of this study was to evaluate the performance of FABR and RABR reactors for the municipal wastewater treatment at laboratory scale and in field conditions to determine their optimum conditions in reaching effluent discharge standards.
Materials and Methods: This study was conducted in Khoy wastewater treatment plant. FABR was operated for 267 days with hydraulic retention time of 18-48 h and RABR was operated for 90 days with media bad rotation of 10-50 rpm. The reactors were fed in line from the wastewater canal. Using composite sampling, 224 samples were taken from the inflow and outflow of the reactors and each sample was analyzed for parameters of COD, BOD, TSS, VSS, TKN, and TP.
Results: The reactor startup took about 107 days. FABR removal efficiency was 93-80, 21-10, and 30-21% for COD, TKN, and PO4 respectively at HRT of 48-18 h. FABR reached effluent disposal standard of TSS, COD, and BOD in all conditions and optimum HRT of 36 h. RABR reached to these standards at HRT 24 h and 50 rpm. However, none of them could meet the nutrient effluent standards.
Conclusion: FABR is an appropriate system for municipal wastewater treatment but for reaching N and P effluent standard, it should be combined with aerobic post-treatment. Moreover, in order to reuse the reactor's nutrient-rich effluent for irrigation; it can be reused as subsurface irrigation.
Rs Hajimirmohammad Ali, H Karyab, Ha Jamali, Mm Emamjome, F Ansari Maleki, A Arezomand,
Volume 9, Issue 4 (3-2017)
Abstract
Improper and incorrect implementation of sewage collection networks can cause environmental and health problems. It also causes dissatisfaction in urban residents. The purpose of this study was to design a questionnaire for evaluating satisfaction level of urban residents from sewage collection network. Face validity index, content validity ratio and Cronbach-coefficient were used to evaluate validity and internal consistency. The evaluated indexes were assessed in acceptable levels. The designed tool that was included 25 variables can be used to assess satisfaction level by researchers and wastewater companies.
M Mokhtari, A Salehi Vaziri, T Zareyi, M Jalili,
Volume 9, Issue 4 (3-2017)
Abstract
Background and Objective: Dewatered sewage sludge is a by-product of wastewater treatment process which can cause health and environmental problems if not properly managed. The aim of this study was to determine the feasibility of composting of Yazd WWT dewatered sludge with windrow method using different treatments.
Materials and Methods: In this study, the dewatered sewage sludge was mixed with two treatments of agricultural wastes (straw) and green waste (leaves), respectively. The mixture was done based on weight ratio of 20:1 and 10:1 (agricultural waste: dewatered sludge, and green waste: dewatered sludge) to achieve a ratio of C/N:20. The windrows were built with a length of 2 m, width of 75 cm and height of 1.5 m. Composting process was controlled by measuring the temperature, humidity, volatile solids, ash, pH, EC, organic carbon and estimating the C/N ratio. The results were compared with those of the Institute of Standards and Industrial Research of Iran.
Results: After 100 days of composting, C/N ratio was 13.08±6.25 in the treatment with green waste and reached to 15.46±5.35 in the treatment with agricultural waste. The amount of volatile solids decreased to 19.8±14.01% and 20.71±16.06% in the treatments with green waste and agricultural waste, respectively. The amount of EC had an increasing trend in both treatments.
Conclusion: composting with both treatments was led to an improvement in indicators of organic fertilizers in dewatered sewage. However, the windrow containing green waste reached to the mature compost standards sooner than the windrow containing agricultural waste.
S Torbati,
Volume 9, Issue 4 (3-2017)
Abstract
Background and Objective: Malachite green dye is used in many industries including textile industries. Disposal of wastewaters containing the dye to the environment, can lead to many environmental problems. Currently, many physico-chemical approaches are used for wastewater treatment. Because of limitations and difficulties of these methods, biological treatment is considered as an economic and effective treatment method. The aim of the present study was to study the feasibility of phytoremediation of malachite green dye using watercress and investigate the effect of some environmental factors in removal efficiency.
Materials and Methods: After collection, the plants were kept in the laboratory, and they were treated with different concentrations of malachite green. During the experiments, decolorization extent was determined by UV-Vis spectrophotometry. Intermediate compounds generated during the biodegradation of the pollutant were identified using GC-MS method.
Results: After 7 days, the ability of watercress in removal and biodegradation of 10 mg/L of malachite green solution was more than 90%. Five intermediate compounds were identified in the biodegradation pathway of the pollutant. It was also found that increasing dye concentration up to 20 mg/L led to the increase of the plant photosynthetic pigment contents and activities of antioxidant enzymes.
Conclusion: Our results showed that watercress has high ability in the dye removal of malachite green. The reusability of the plant for decolorization confirmed the biological degradation process. Moreover, an increase in the plant biomass, temperature and pH led to the increased decolorization efficiency.
Sh Gorgani, A Bafkar, Se Fatemi,
Volume 9, Issue 4 (3-2017)
Abstract
Background and Objective: There are major mobile and non-mobile pollution sources due to human activities that can influence aquifers and reduce groundwater quality. Vulnerability assessment is an inexpensive procedure in to identify areas prone to the pollutants. Identification of these sources is essential in water resources management. Mahidasht Plain is one of the important regions of Kermanshah province and plays a significant role in the production of agricultural products. Water supply for agriculture may be at risk due to the indiscriminate withdrawal of groundwater resources of the plains, the recent droughts and potable water requirements. Therefore, analysis and evaluation of the area helps to make better decisions on proper management and control of water pollution.
Materials and Methods: Vulnerability, which is defined as the sensitivity of groundwater quality to pollution load, was applied and determined using intrinsic features of the aquifer. In this study, we have studied inherent vulnerability of the Mahidasht aquifer against pollution by using DRASTIC model and GIS. Seven parameters for the zoning of aquifer vulnerability was used in the DRASTIC method, including depth to the water table, net recharge, aquifer material, soil type, topography, impact of vadose zone and hydraulic conductivity. These parameters were prepared as seven layers of information in Arc GIS10 Software. The data collected for the purpose of this study were taken fromwells log, 44 piezometer in the area, pumping experiments and three rain-gauge stations. The layers prepared in Arc GIS10 software were weighted, ranked and eventually integrated.
Results: The DRASTIC index calculated for the plain ranged from 34 to 120 units. On this basis and according to the standards listed for DRASTIC index, the aquifer was in a vulnerable group with a low or no risk.
Conclusion: DRASTIC model output showed an inherent vulnerability of the aquifer. The model can be used as a primary tool in the development and management of water resources in the future. In addition, this model is not able to produce information about amount and type of pollutants. Therefore, it is recommended to examine the salinity zoning in the future research due to less rainfall and decreasing underground water level and consequently the higher probability of salinity in underground water. Additionally, the domestic and industrial wastewater, sewage irrigation and the fraction used for groundwater recharge should be considered in order to validate the results of Drastic model.
M Kolahkaj, S Battaleblooie, H Amanipoor, S Modabberi,
Volume 9, Issue 4 (3-2017)
Abstract
Background and Objective: Arsenic accumulation in rice has become a major disaster in the recent decade. A number of studies indicated that rice is a major source of arsenic pollution in human diets. This study assessed the arsenic (As) accumulation in rice grain in Meydavood where rice is the main agricultural crop of the region. This research studied the probable presence of arsenic in the rice grains of Maydavood region in Khozestan province and evaluated the arsenic intake through daily rice consumption.
Materials and Methods: Ten rice samples were taken from Meydavood farms during cropping time. Samples were analyzed for arsenic using ICP-MS.
Results: Data were analyzed using SPSS statistical software and then compared with the World Health Organization standards. The mean concentrations of arsenic in rice samples were 0.079 ppm based on dry weight. The results showed that in 30% of the samples, arsenic concentration exceeded the WHO standards. Due to the high concentration of arsenic in rice samples, the arsenic intake by human was calculated using a regimen of safety and considering a consumption rate of 110 g of rice per day and an average body weight of 70 kg.
Conclusion: The total daily intake of As (TDI-iAs) for adults (70 kg body weight and 110 g rice consumption) was in the range of WHO recommended provisional tolerable daily intake value. Since the source of arsenic in Meydavoud is a natural source, thus, comprehensive studies are recommended on its water resources. Additionally, a solution should be found to prevent probable health effects on the residents.
R Nabizadeh Nodehi, Ar Mesdaghinia, S Nasseri, M Hadi, H Soleimani, P Bahmani,
Volume 9, Issue 4 (3-2017)
Abstract
Background and Objective: Water corrosion and scaling are known as destructive phenomenon of drinking water quality and water facilities. In this study, the groundwater tendency to corrosion or scaling in source water, water storage reservoirs and distribution system were studied. Simultaneous use of some qualitative and a quantitative index along with statistical analyses to assess the water scaling or corrosion tendency were investigated.
Materials and Methods: The data analysis of groundwater, water storage reservoirs and water distribution system in rural area of Kurdistan province were analyzed and the amount of Langelier (LI), Ryznar (RY), Pockorius (PSI) and Larson–Skold (LS) and CCPP indices were determined. Corrosion and scaling threshold for qualitative indices were determined based on CCPP index. The mean of indices was compared with the thresholds using independent t-test. ANOVA was used to assess the difference between the indices in different sources of water.
Results: The balance range for LI, RY and PSI found to be -0.1-0.05, 7-9 and 7.1-8.5. The mean CCPP for groundwater, reservoirs and networks were 9.27 ± 1.29, 9.13 ± 1.25, 11.25 ± 1.23, respectively. All three sources of water have some tendencies toward scaling; however, a significant balance status was confirmed statistically. According to Larson–Skold index, sulfate and chloride anions did not play a role in scaling process.
Conclusion: The use of qualitative indices with CCPP index can provide more accurate estimation of water tendency toward scaling or corrosion. The assessment of qualitative indices along with CCPP is recommended in drinking water corrosion monitoring studies.
L Kiyani, Se Rezatofighi, H Motamedi,
Volume 9, Issue 4 (3-2017)
Abstract
Background and Objective: The use of household water filter systems has been widely increasing in recent years because of water pollution. In water filter systems, bacterial biofilm forms on the surface of the membranes, thereby increasing the possibility of transferring antibiotic resistance among bacteria and allowing their entry into the human body. This study analyzed the types of bacteria that grow in the membranes of water filter systems and their antibiotic resistance.
Materials and Methods: For this study, samples were collected from 80 membranes of household water filter systems. Bacteria grown on these membranes were identified using biochemical and molecular methods. Resistance against antibiotics including penicillin, tetracycline, erythromycin, gentamycin, cephalexin, and trimethoprim-sulfamethoxazole was evaluated by disk diffusion method.
Results: The detected bacteria included Pseudomonas, Rhodococcus, Bacillus, Sphingomonas, Zymomonas, Aeromonas, Klebsiella, Citrobacter, Drexia and Achromobacter. Majority of the isolates were identified as Pseudomonas aeruginosa. The antibiogram test showed that most of these bacteria exhibited multi-drug resistance (MDR). Maximum resistance was observed toward cephalexin and the least resistance was toward gentamicin.
Conclusion: The results revealed that membranes of household water filter systems were suitable environments for the growth of bacteria. In these conditions, MDR bacteria presumably could transfer antibiotic resistance genes to bacteria and microflora of the human body through water. Therefore, membranes should be designed in such a manner that not only they can remove the bacteria from water but also kill them.
M Heydari, R Nabizadeh Nodehi, M Ali Mohammadi, K Yaghmaeian,
Volume 10, Issue 1 (6-2017)
Abstract
Background and Objective: Bottled water consumption is rapidly increasing in recent years for various reasons.The main aim of this study was to survey the geological origin of Iranian bottled water and determine compliance or lack of compliance with the experimental data obtained through sampling 71 brands of drinking bottled water and mineral water.
Materials and Methods: In this study the coordinates of access points as a georef of the chosen points were launched on the "Iran geological map" and "Iran mineral and warm water map." The compliance of laboratory data and water types with the geological data were evaluated and compared with the important ionic ratios of the extracted water through using awh software.
Results: In examining 71 brands of the bottled water, 28% of the brands did not agree with the laboratory results, reflected by observing higher levels of bicarbonate in 50% of the bottled waters than those of the geological data.. Additionally, 70% of water types were calcic bicarbonate. In the bottled waters from North Alborz range with coastal Time deposits around the Caspian Sea, there was a source of brine or sea water that was about 55% of this amount.
Conclusion: Water pass through different geological structures and the dissolution phenomenon might be an important factor for the observed disagreement. Because chemical treatment and use of additives on mineral waters are not allowed it prompts further studies to determine the cause and origin of this issue through sampling from the factory and water source.
P Baratpour, G Moussavi, A Alahabadi, E Fathi, S Shekoohiyan,
Volume 10, Issue 2 (9-2017)
Abstract
Background and Objective: With industrial development and population growth, the emerging contaminants enter into the natural water resources. Therefore, adsorption potential of Ammonium Chloride-induced activated carbon (NAC) to remove metolachlor pesticide from contaminated water was investigated in this study.
Materials and Methods: The effects of operational conditions including solution pH, NAC concentration, metolachlor initial concentration and contact time on the removal of metolachlor by Ammonium Chloride-induced activated carbon (NAC) and standard activated carbon (SAC) were studied.
Results: Over 92.4% of 50 mg/L metolachlor was adsorbed using 0.3 g NAC/L within 5 min, and by increasing the reaction time to 60 min the removal efficiency reached to 100%. Under similar experimental conditions, standard activated carbon (SAC) could only adsorb 20% of metolachlor within 5 min and increase of contact time to 40 min caused the improvement of metolachlor adsorption onto SAC to 48%. The adsorption onto SAC was not influenced by the contact time over 40 min. Kinetic analysis showed that experimental adsorption data for both NAC and SAC were best fitted to the pseudo-second-order model. The maximum adsorption capacities of metolachlor onto NAC and SAC calculated by the Langmuir model were 344.8 and 238.1 mg/g, respectively.
Conclusion: Generally, these results showed that developed NAC was an efficient adsorbent with high removal efficiency for eliminating the halogenated pesticides from the contaminated water streams.
R Shokohi, A Shabanloo, F Zamani,
Volume 10, Issue 2 (9-2017)
Abstract
Background and Objective: Nitrophenols are among the most common and toxic compounds in industrial effluents that 2, 4 dinitrophenol (2, 4-DNP) is the most toxic compound in this group. The object of this study was to optimize the removal of 2, 4-DNP by thermally activated persulfate using a central composite design.
Materials and Methods: This study was performed on a batch thermal reactor with a volume of 4 L. In this study, a central composite design (CCD) with RSM method was used for designing and optimizing the operation parameters such as initial pH of solution, potassium persulfate concentration and temperature. The effect of 2, 4-DNP concentration and reaction time at optimum conditions were also investigated.
Results: The results indicated that the degradation rate of 2, 4-DNP was enhanced by increasing the concentration of persulfate and reducing temperature and pH. The optimum conditions for the highest degradation efficiency (99%) were as initial concentration 10 mg/L, reaction time 30 min, temperature 60 °C, Potassium persulfate concentration 10 mmol/L, and pH 5. At the optimum conditions, when 2, 4-DNP concentration was increased to 50 mg /L, the 2, 4-DNP degradation rate decreased to 73%.
Conclusion: This study indicated that the heat-activated PS oxidation could be an efficient approach for decomposition of 2, 4-DNP. Temperature was the most influential variable in this regard (p<0.0001).
F Akhlaghian, H Azadi,
Volume 10, Issue 2 (9-2017)
Abstract
Background and Objective: All around the worlds, wastewater containing dye pollutants are considered serious problem. Rhodamine B dye which is used in textile, leather, drug, and cosmetic industries exert carcinogenic and strong toxic effects. The aim of this research was to remove of Rhodamine B dye by nanowires of zinc oxide doped with lanthanum.
Materials and Methods: In this work, nanowire of zinc oxide doped with lanthanum was synthesized by hydrothermal method. The obtained photocatalyst was characterized by XRF, XRD, and SEM method. Effects of batch process variables such as pH, initial concentration of Rhodamine B, and photocatalyst dose were investigated. The kinetics of the reaction was also studied.
Results: The SEM images showed a hexagonal structure of ZnO, and La/ZnO nanowires. XRD results also confirmed the formation of ZnO with wurtzite hexagonal structure in both samples (ZnO and La/ZnO). The kinetics studies showed that the reaction was a pseudo first order. The apparent constants of ZnO and 2%La/ZnO nanowires were 0.0045 min-1 and 0.0074 min-1; respectively. In a batch experiment, the degradation yield of 99.8% was obtained at operating conditions of 1.25 g/L of 2% La/ZnO photocatalyst, initial concentration of Rhodamine B solution 4.78 mg/L, and pH=9 under ultra violet irradiation for 4 h.
Conclusion: The nanowire of La/ZnO with an optimum load of lanthanum has a better photocatalytic activity than nanowire of ZnO for degradation of Rhodamine B in aqueous solution.
