Iranian Journal of

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Background and Objectives: Silica is an inorganic material that found in the nature in various forms. The hazards of crystal of silica or α-quartz (free silica) is greater than other forms. Exposure to dust that contains free silica result to pulmonary injury and result to silicosis and death finally. The present research was conducted in order to evaluate the level of workers exposure to free silica in air of Khaf Iron stone quarries.Materials and methods: The exposure level to total and respiratory dust measured based on personal and environmental sampling methods and concentration of dust determined based on gravimetric method. For determination of amounts of free silica, dust samples analyses based on X-ray diffraction (XRD) method, and results compared with standard levels.Results: The maximum amount of total dust and free silica measured in stone breaking station (800±155mg/m³ and 26.11±6.7 mg/m³) and minimum of them measured in official and safeguarding station (8.28±2.2 mg/m³ and 0.012±0.0019 mg/m³). The maximum amount of respiratory dust and free silica measured in red mound digging number 1 (66.14±13.45 mg/m³ and 1.48±0.39 mg/m³) and minimum of them measured in air hammer machine station (5.26±2.62 mg/m³ and 0.01±0.005 mg/m³).Conclusion: Amount of total dust only in official and safeguarding station was lower than standard levels of Iran. Amount of respiratory dust in all stations was greater than Iran standard levels. Furthermore the level of respiratory free silica only in airy hammer machine station was lower than standard level of Iran. Regarding to this amounts it is so essential to that with applying different methods generation and emission of dust protected.

 

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Background and Objectives: Measurement of light intensity is a recommended practice for insuring the delivery of required germicidal dose in disinfection operations by UV lamps. Use of sensitive to light chemicals which is the base of actionometeric methods could be considered as a suitable manner for estimating the intensity of UV lamp in circumstances that special radiometers are not available.
Materials and Methods: lodide-iodate mixture was used as an actinometer for this study. The light intensities of a UV lamp (LP 25W) were first determined by a special UVC ‌radiometer at certain distances from the lamp. Then the test of determining the suitable period of time for irradiation of actinometer was accomplished.  Finally، the color changes of iodide - iodate solutions at the predetermined distances were evaluated at the wavelength of 352 nm. The latter analysis can be done by a common (visible) spectrophotometer.
Results:‌ Results indicated that use of this actinometer is more suitable at the distances of 35 to 60 cm from the center of the lamp bulb، since iodode-iodate solution has a detectable color change at this range of distance in one minute irradiation which may be considered as a reasonable time for actionmeteric operations.
Conclusion:  Although all kinds of actinometers should not be regarded as precise as special radiometers and there would be need to use pure chemicals for actinometeric determination of light intensity، it can be claimed that the recommended procedure in this study which is the newest actinometeric method can be used in acceptable evaluation of UV intensity with least difficulty in providing necessary instruments.

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Backgrounds and Objectives: Cyanide is a species of high toxicity that found mostly in industrial effluents such as electroplating, metal mining, metallurgy and metal cleaning processes. Intrance of it to Existence enviroment contains very health hazardous. Purpose of this study, efficiency compare of both sonochemical and photosonochemical technologies for cyanide removal from aqueous solutions.
Materials and Methods: in this study, it has been used from a productive set of 500w power ultresound waves in of two frequencies 35 kHz and 130 kHz and a 125 W low pressure mercury lamp. Experiments were performed at initial cyanide concentrations varying from 2.5 to 75 mg/L. in this study, The effects of parameters such as pH, time and initial cyanide concentration on the sonochemical and photosonic degradation have been studied.
Results:The results of the study showed that the maximom removal efficiency of cyanide had been achieved sonochemical technology was 71% while it was 74% by photosonic at frequency of 130 kHz, at time of 90 min, pH of 11 and initial cyanide concentration of 2.5 mg/l.
Conclusion: The results of the study showed that efficiency of photosonic process is more than for sonochemical cyanide removal fromaqueous solutions.Also efficiency of cyanide removal has direct relationship with pH, frequeny and time ,and it has reverse relationship with cyanide concentration for both processes.

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Backgrounds and Objective: Surfactants are one of the largest pollutants which exist in urban and industrial wastewaters. Large quantities of surfactants have entered to the environment since last decade due to increased use of synthetic detergent in industrial and home consumptions.In this study, the efficiency of UV/H2O2 process in removal of linear alkylbenzane sulfonate (LAS) from aqueous solutions was investigated.
Materials and Methods: In this study methylene blue active substane(MBAS)method and spectrometery were used to determine anion and residual surfactant respectively. In this study important variables were H2O2 concentration, initial concentration of surfactant, pH and duration of UV radiation. The effect of UV/H2O2 process on the degradation of LAS was analyzed statistically by using Multiple Linear Regression test.
Results: The resulted showed that after 20 minute, ultraviolet radiation solely removed 38.44 percent of Anionic detergent, Hydrogen peroxide showed no significant removal of detergent solution in the time course study. The efficiency of UV/H2O2 process in 10, 20 and 30 minute were to 86.2, 90 and 96.5 %, respectively.
Conclusion: The results showed that the efficiency of ultraviolet radiation and hydrogen peroxide process in anionic detergent was not significant thoogh it was considerable in combination process (UV/H2O2).

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Backgrounds and Objectives: Phenol and phenolic compounds are widely used in industry and daily liFe, and are of high interest due to stability in the environment, dissolution ability in water and health problems. In this regard, phenol removal from water is of high importance. The purpose of this study was to investigate the efficiency of photodegradation process for removal of phenol from aqueous system by use of Fe-doped TiO2 nanoparticles prepared by sol-gel method.
Materials and Methods: Phenol concentrations of 5, 10, 50 and 100 mg/L were prepared and exposed to UV and Fe-doped TiO2, separately and simultaneously. Also the effect of initial phenol concentration, Fe-doped TiO2 loading and pH were studied. Various doses of photocatalist investigated for Fe- doped TiO2 were 0.25, 0.5 and 1 g/L. pH was studied at three ranges, acidic (pH=3), neutral (pH=7) and alkaline (pH=11).
Results: Maximum degradation was obtained at acidic pH, 0.5 g/L of Fe-doped TiO2 for all of phenol concentrations. With increasing initial concentration of phenol, photocatalytic degradation decreased. In comparison with Fe-doped TiO2/UV process, efficiency of UV radiation alone was low in phenol degradation (% 64.5 at 100 mg/l of phenol concentration). Also the amount of phenol adsorbed on the Fe-doped TiO2 was negligible at dark conditions.
Conclusion: Results of this study showed that Fe(III)- doped TiO2 nanoparticles had an important effect on photocatalytic degradation of high initial phenol concentration when Fe(III)-doped TiO2/ UV process applied.

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Background and Objectives: Heavy metal pollution has always been a major cause contamination of environment and considered as a major concern for food health. Rice is the most popular food among Iranians and presence of heavy metals in trace level in rice has received special attention because they are directly related to health.The aim of this research was to investigate the concentration of Pb, Cd, Cr, Ni in rice prevalent in the market of Iran.
Materials and Methods: 20 of the most widely consumed brands of Iranian rice were purchased from local market in Iran. 3 samples of each brand were collected and certain volumes of each sample were digested with acid. Heavy metal contents in the digested samples were determined by atomic absorption spectrometry.
Results :The results showed that mean concentration Pb , Cr , Ni in rice samples respectively was 0.387 , 0.683, 0.019 ( mg/kg )
Conclusion: Notably the Ni and Cr content in the rice samples was found to be below the food sanitary standards in India rice . In the other hand 50% samples content Pb was found to be upper the food sanitary (Pb: 0.3 mg/kg). The result indicated that weekly intake of heavy metal by rice was below the provisional tolerable weekly intake recommended by WHO/FAO. However, risk assessments needs considerable attention and better prevention this low pollution.

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Background and Objectives: Fresh leachate has a low pH and high amounts of BOD and COD which are mainly constituents with low weight molecular such as volatile fatty acids ( acetic and propionic acids) .Management and treatment of leachate is an important subject in sanitary landfill operation and performance.Th objective of this study is determining the efficiency of the integrated coagulation -flocculation and ozonation processes in fresh leachate treatment of Tabriz city.
Materials and Methods: Quantitive parameters of pH, BOD5, COD , alkalinity and TSS were studied based on standard methods.The study emphasizes of COD and TSS leachate removal.Alum , ferric chloride and PAC had been used as coagulants.
Results : Results indicated the superiority of Ferric chloride at the dosage of 1 g/l in pH 10 ,whichreduced 34% of COD and 54% of TSS.in the stage of ozonation the leachate sample coagulated by ferric chloride was treated by 3 g/h ozone gas at optimum pH and after 39 hours ozonation about 51% of COD and 18.2 % of TSS were reduced.
Conclusion: This study clearly indicates that there would be need to apply biological treatment (after coagulation - flocculation ) and ozonation , various advanced oxidation processes and / or other treatment methods for further reduction of COD in leachate and meeting discharge standards.

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Background and Objectives: Nowadays, most countries of the world have shortage of water due to many reasons such as population growth, rising of living standards, indiscriminate water use, and so on. Besides, in absence of adequate water resources, desalination of brackish and saline waters have been used to supply potable water. Freezing process is one of the methods which can be used to desalinate saline waters.The aim of this study was to survey freezing process to produce potable water from saline water of Persian Gulf shores.
Materials and Methods: This study was conducted in lab-scale by using indirect contact freezing. Three samples of 50 liter were provided from Bushehr shores. The implemented process steps were freezing (crystallization), separation of crystals, surface washing, and thawing. Freezing of the samples (each in 0.5 liter containers) were performed by a refrigerator at -20°C and 0.1KW/h energy consumption.
Results: The removal efficiencies of TDS in the first, second, and third samples by first freezing process were 56, 56, and 51 percent, respectively. Moreover, the removal efficiencies by EC were 42, 44, and 40 percent, respectively. Meanwhile, the removal efficiencies of TDS in first, second, and third samples by second freezing process observed 69, 69, and 68 percent, respectively. Moreover, the removal efficiencies by EC were 61, 60, and 63 percent, respectively. Also, the removal efficiencies of TDS in first, second, and third samples by third freezing process were 72, 73, and 72 percent, respectively. Moreover, the removal efficiencies by EC were 77, 78, and 77 percent, respectively. The production of the potable water by this method was 15-20 percent of the entry water.
Conclusions: According to the obtained results, potable water was obtained after third freezing of the saline water. Meanwhile, TDS of the produced water was less than maximum allowed concentration of Iranian standards.

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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.

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Background and Objectives: Free living nematodes due to their active movement and resistance to chlorination don't remove in conventional water treatment processes thus can be entered to distribution systems and cause adverse health effects. UV irradiation can be used as a method of inactivating these organisms.
Materials and Methods: This study is done to investigate the effect of ultraviolet lamp on inactivation of free living nematode (Rhabitidae) in water. The effects of duration of irradiation, turbidity, temperature, UV dose and pH are investigated in this study. Ultraviolet lamp used in this study was a 11 watt lamp with intensity of 24 µw / cm².
Results: Contact time required to achieve 100% efficiency for larvae nematodes and adults were 9 and 10 minutes, respectively. Increase of turbidity up to 25 NTU decreased inactivation efficiency of larvae and adult nematodes from 100% to 66% and 100% to 64%, respectively. Change in pH ranged from 6 to 9 did not affect the efficiency of inactivation. With increasing temperature inactivation rate increased.
Conclusion: The results showed that there was a significant correlation between the increase in contact time, temperature rise and turbidity reduction with inactivation efficiency of lamp)p<0.001(. Also the effect of the lamp on inactivation of larvae nematode was more than the adults.

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MicrosoftInternetExplorer4 Background and Objectives: since there is not any information about the quality and quantity of carpet cleaning wastewater, this study was done for the evaluation of carpet cleaning wastewater   characterization in Tehran.
Materials and Methods: There are 122 carpet-cleaning units in Tehran. Compound samplings were taken from 10 randomly selected carpet-cleaning units. Each unit was sampled 5 times and analyzed based on the Standard Methods. Quality parameters measured included chemical oxygen demand (COD), detergent, color and suspended solids (SS), and data was analyzed using statistical software spss16.
Results: Results showed that the amount of water usage for carpet cleaning was 30.84 liters per square meter of carpet washed. The average level of COD, color, detergent and SS in the effluent of carpet cleaning unit was 367.4   mg/l, 171.85 ADMI, 55.51 mg/l and 359.62 mg/l, respectively.
Conclusion: The effluent characteristics of carpet cleaning units are almost with in the domestic wastewater range. However, since these wastes are disposed untreated into the environment which are then enter surface and groundwater, all measured parameter were higher than proposed standards regulated by EPA, So treating process must be done before disposal.

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A MicrosoftInternetExplorer4 Backgrounds and Objectives: Large quantities of sludge are produced in biological wastewater treatment. Because this sludge is highly rotten, it should be stabilized before its disposal. Aerobic and anaerobic digestion is widely considered as stabilization techniques. Because of high retention time and sludge dewatering difficulties, reduction in retention time, operation and maintenance should be given into consideration. Ultrasonic process increases the enzymatic activity, so decreases the hydrolysis time, a limiting factor in digestion process, and contributes to the decrease of the detention time. The objective of this investigation is to determine the effect of ultrasound in improving dewatering and stabilization of aerobic and anaerobic digested sludge. In addition, the impact of ultrasonic treatment on improvement of sludge dewatering and aerobic and anaerobic digestion is compared.
Materials and Methods: In this survey, samples of aerobic and anaerobic digestion were collected from local full-scale Garb Town and Tehran South wastewater treatment plant, respectively. The grab samples were collected for 4 month from July to October 2010. Total numbers of 20 samples were collected biweekly for each type of digestion. Each sample was sonicated for 15, 30, 60, and 90 min under 35 and 131 kHz frequencies separately. Total solids, volatile solids , pH, temperature , total COD, dissolved COD and settle able solids were measured. Ultrasound bath of the solution in a 300 mL glass reactor was performed as a bath reactor with power of 500 W.
Result: The results showed that the application of ultrasonic wave increased dissolved COD and temperature and decreased volatile solid, pH and settle able solids. Application of ultrasonic wave with frequency of 131 kHz decreased the VS and increased the dewatering of sludge more effective than the 35 kHz frequency and the highest performance was at 15 min of time and 131 kHz of frequency. Also sonication method showed better efficiency for anaerobic sludge samples compared to the aerobic sludge samples.                 
Conclusion: The results obtained showed that digestion and dewatering properties of sludge improved by ultrasonic application. Therefore it can be used as an alternative method for the sludge treatment.

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MicrosoftInternetExplorer4 Background and Objective: Dioxins and Furans are dangerous and highly toxic compounds entering to the environment from natural and manmade sources. Having high stability and half-life, these compounds remain for a long period in the medium and bring about severe effects on human beings and the environment. The aim of this study was to identify dioxins and furans emission sources in Iran and to estimate their contribution in emission rate.
‌Materials and Methods: First, we identified the emission sources of dioxins and furans and then necessary data was gathered by referring to the authorized organizations and filling the prepared UNEP questionnaires. We used Excel software to analyze the data collected.
Results: According to the results obtained, total dioxins and furan emission in Iran in 2010, was 1957 g TEQ/yr out of this amount, 705.8 g TEQ is emitted to the atmosphere and 643.2 g TEQ is residual ash. Therefore, dioxins and furans emission rate was 26.4 µg TEQ/capita in Iran. The most rates of emissions were associated with uncontrolled open burning (732.8 g TEQ/yr) and ferrous and nonferrous metal production (635.7 g TEQ/yr) such as cupper, iron, and steel.
‌Conclusion: Our findings showed that the emission rate of Dioxins and Furans is much higher in Iran compared with other countries and appropriate management strategies are required to control these dangerous pollutants.

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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.

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Backgrounds and Objectives: The base structure of total petroleum hydrocarbons (TPH) is made of hydrogen and carbon. Widespread use, improper disposal and accidental spills of this compounds lead to long term remaining of contaminations such as organic solvents and poly aromatic hydrocarbons (PAHs) in the soil and groundwater resources, resulting in critical environmental issues. In this study, an oil-contaminated soil was washed using Tween 80 surfactant and the application of photo-Fenton process (UV/Fe²⁺/H₂O₂) for treatment of the produced wastewater was evaluated.
Materials and Methods: Tween 80 is a yellow liquid with high viscosity and soluble in water. In order to determine of the photo-Fenton process efficiency, we studied effective variables including Fe concentration, pH, H₂O₂ concentration, and irradiation time. The UV irradiation source was a medium-pressure mercury vapor lamp (400 w) vertically immersed in the solution within 2L volume glass cylindrical reactor.
Results: The results showed that efficiency of COD removal depends on the initial Fe concentration, pH, H₂O₂ concentration and irradiation time.
Under optimum conditions, (Fe: 0.1mM, H₂O₂: 0.43 mM, pH: 3 and UV light irradiation time: 2 hours) the removal efficiency of COD was 67.3%. pH plays a crucial role in the photo-Fenton process such that the removal efficiency increased with decreasing of pH.
Conclusion: According to the results of this study, under acidic condition, this process is an efficient method for COD removal from the wastewater studied.

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Background and Objectives: Dyes are an important class of pollutants, which can even be identified by naked eye. Disposal of dyes in precious water resources have been prohibited, however, various treatment technologies are in use. Among various methods adsorption occupies a prominent place in dye removal. Therefore, natural zeolite (clinoptilolite) and acid modified zeolite were used as a low-cost adsorbent to evaluate their ability to remove color from aqueous solution using a batch adsorption experiments. Materials and Methods: Modification of zeolite surface was carried out with two acids sulfuric acid and phosphoric acid, to improve the removal efficiency of reactive blue 19. We studied the influence of acid concentration, contact time, solution pH, initial dye concentration, and adsorbent dosage on the removal efficiency. Results: The parameters of Langmuir and Freundlich adsorption isotherms have been determined using the adsorption data. Equilibrium adsorption data followed both Langmuir and Freundlich isotherms. It was also found that adsorption of dye by zeolite followed pseudo first-order kinetics. The adsorption results indicated that natural zeolite has a limited adsorption capacity for reactive dye but can be distinctly improved by modifying its surfaces with acid. Experimental results also showed that sulfuric acid has better performance than phosphoric acid in the modification of zeolite for dye adsorption. Conclusion: We achieved the best results in terms of removal efficiency (41-72%) for the zeolite modified with Si/Al ratio of 7.5 after 3 h of contact.

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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.

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MicrosoftInternetExplorer4 Background and Objectives: Synthetic dyes represent one of the largest groups of pollutants in wastewater of dying industries. Discharging these wastewaters into receiving streams not only affects the aesthetic but also reduces photosynthetic activity. Electrochemical advanced oxidation processes such as Electro-Fenton process are low operational and have high mineralization degree of pollutants. In this study, we investigated affective factors in this process to determine the optimum conditions for dye and COD removal from aqueous solutions containing Reactive Blue 19 dye.
Materials and Methods: Synthetic samples containing Reactive Blue 19 dye were prepared by dissolving dye powder in double distilled water. and the the solution prepared was transferred into pilot electrochemical cell having two anode and cathode electrode made of iron and carbon. Electro-Fenton process was began by adding of Fe²⁺ ions and establishing electrical potential difference. After testing and at specified time intervals, each sample was collected from the pilot cell, and process performance was evaluated through measuring dye concentration and COD.
Results: Based on the results obtained, optimum conditions of Electro-Fenton process for dye and COD removal was determined. Accordingly, potential difference of 20 volt for dye concentration up to 100 mg/L and potential difference of 30 volt for dye concentration of more than 200 mg/L, reaction time 60 minutes, 0.5 mg/L of Fe²⁺ concentration and suitable pH for the maximum dye removal efficiency equaled 4 respectively. Under such conditions, the dye and COD removal was 100 and 95% respectively.
Conclusion: Based on the results obtained, it was revealed that Electro-Fenton process has significant ability in not only dye removal but also in COD removal. Accordingly, it was found that the effective parameters in Electro-Fenton process for removal Reactive Blue19 dye are electric potential difference, concentration of iron ions and electrolysis time.

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Background and objectives: Bisphenol A (BPA) is an endocrine disrupting chemical that releases to the environment through effluents of its producing factory, pulp and paper mill factories, and plastics industry. The purpose of this study was to investigate adsorption isotherms of removing BPA from aqueous solutions using single walled carbon nanotubes (SWCNTs). Materials and methods: This study was an empirical investigation. Our experiments were conducted discontinuously using 50 mL of sample in each test. The variables of this study were the contact time (5, 15, 30, 60, 90, 120 min), the initial concentration of BPA (2, 5 , 20, 50 mg/L), and pH (3, 5, 6, 9, 11). The concentrations of BPA were measured using UV-Vis spectrophotometer. Results: The maximum adsorption capacity was found to be 71.42 mg/g. The results of our experiments showed that maximum adsorption capacity at equilibrium was achieved at t = 60 min and pH = 9. Moreover, increasing the initial concentration is associated with an increase in adsorption capacity until it becomes constant. Conclusion: The BPA adsorption on SWCNT follows Freundlich-Langmuir isotherm.

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Background and Objectives:Chlorination is the most common method of water disinfection. Chlorine reaction with natural organic compounds nor removed completely during treatment process would result in forming disinfection byproducts. Followed by trihalomethanes, Haloaceticacides are the second main byproducts of chlorination in water. The research works conducted in Iran have assessed trihalomethanes. Hence, this is the first time we are reporting haloacetic acids in Iran. Materials and Methodology: We collected samples from surface water resources and treated water in Tehran for six consecutive months (first half, 2010). We measured temperature, pH, UV adsorption at 254 nm and TOC in each surface water sample and analyzed pH, residual chlorine, and haloacetic acids in the treated water samples. Results: We found that TOC in surface water resources is 3.6-4.42 and 1.78-2.71 mg/l in spring and summer respectively. Moreover, haloacetic acids concentration was found to be 41.7-55.56 and 34.83-43.73 μg/l in spring and summer respectively. Conclusion: Our results revealed that concentration of NOM, TOC, and HAAs was more in spring than summer. In addition, concentration of HAAs was depended up on NOM and TOC. Considering maximum permeable concentration of HAAs (60 μg/l) by EPA, it can be claimed that concentration of HAAs was less than the maximum permissible level in all of the samples. However, the immanency of the monitored values to the standard values can be a warning for concerned authorities in water industry.