Alireza Abbasi; Saeed Yosefinejad; Shima Bahrami; Mohamad Hoseini
Abstract
Introduction: Carbon monoxide (CO) is an odorless, tasteless, colorless, and nonirritating poisonous gas, recognized as the silent killer for the 21st century. It is produced during partial combustion of carbon-containing compounds. Improper ventilation and flue installation of vented gas space heaters ...
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Introduction: Carbon monoxide (CO) is an odorless, tasteless, colorless, and nonirritating poisonous gas, recognized as the silent killer for the 21st century. It is produced during partial combustion of carbon-containing compounds. Improper ventilation and flue installation of vented gas space heaters cause carbon monoxide gas to penetrate the building, leading to many deaths annually. The catalytic oxidation of CO has received great attention due to its applications in different fields. In this study, alumina foam coated by CuMnOx catalyst was used to remove CO from the vented gas space heaters. Method: This is a full-scale experimental study on the outflow from vented gas space heaters. Alumina foam supported hopcalite (CuMnOx) catalyst was synthesized using a co-precipitation method for CO oxidation from THE vented gas space heaters. The XRD and SEM were used to characterize the synthesized catalyst. The concentration of CO was measured by IMR 1500 combustion gas analyzer. Result: The particle size of the catalyst was in the range of 200-600 nm. XRD showed different crystallizations, and the crystal size was in the range of 20 -120 nm. There was no significant CO removal in the case of using uncoated alumina foam. Results showed CuMnOx catalyst significantly increased the CO removal. The removal efficiencies were 83% and 89% in heating powers of 2300 and 3200 kcal/hr, respectively. The average CO conversation rate was approximately 60.45 µg/gr.min. Conclusion: CuMnOx coated on alumina has a significant effect on CO removal from the vented gas space heaters. The catalyst and outlet gas temperature were the most important factors affecting CO removal.
Mohammad Reza Samaei; Razieh Ashoori; Abooalfazl Azhdarpoor; Saeed Yousefinejad
Abstract
Background: Simultaneous existence of excessive amounts of fluoride and nitrate in drinking water can cause health problems for humans. In this study, simultaneous removal of fluoride and nitrate from aqueous solutions was investigated using a combination of electroreduction and electrocoagulation processes ...
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Background: Simultaneous existence of excessive amounts of fluoride and nitrate in drinking water can cause health problems for humans. In this study, simultaneous removal of fluoride and nitrate from aqueous solutions was investigated using a combination of electroreduction and electrocoagulation processes in a batch reactor with different electrodes. Methods: In this study, at first, an optimum electrode was selected. Afterward, the effects of different operating parameters such as the current density (12- 36 mA/cm2), initial pH (5.5-8.5), NaCl concentration (0.5-1.5gr/L), and electrolysis time (15-120 min), ) on the removal of fluoride (initial concentration: 6 mg/L) and nitrate (initial concentration: 150 mg/) were evaluated, respectively. Results: The highest efficiency of the concurrent fluoride and nitrate removal with Al-Cu electrode and in optimal experimental conditions of the current density of 36 mA/cm2, pH of 7, NaCl concentration of 1gr/L, and electrolysis time of 90 minutes was obtained 87.04 and 89.70%, respectively. Conclusion: High catalytic activity of the copper cathode resulted in better performance than other cathodes in the simultaneous removal of fluoride and nitrate. Generally, it can be concluded that the electrochemical process can reduce the levels of fluoride and nitrate to the amounts below the WHO standard limits, 1.5 mg/L and 50 mg/L, respectively.
Zohre Moeini; Abooalfazl Azhdarpoor; Saeed Yousefinejad; Shima Bahrami
Volume 6, Issue 1 , January 2018, , Pages 8-15
Abstract
Background: Atrazine is one of the most widely used chlorinated herbicides with properties, such as sustainability in soil and ability to penetrate into water sources. This study aimed to investigate the photo-degradation of atrazine using ultraviolet ray and to identify its by-products. Methods: The ...
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Background: Atrazine is one of the most widely used chlorinated herbicides with properties, such as sustainability in soil and ability to penetrate into water sources. This study aimed to investigate the photo-degradation of atrazine using ultraviolet ray and to identify its by-products. Methods: The efficiency of atrazine removal under UV irradiation with a power of 6-125 watts was investigated and some effective parameters, such as initial concentration (10-100 mg/l) and pH (3-5), were studied during the radiation period (5-90 minutes). In all experiments, the volume of the solution used in 250-ml Erlenmeyer flask was 100 ml. After all, the final and by-products produced during this process were identified by mass gas chromatography. Results: The results showed that the removal efficiency did not change significantly by increasing pH. With increasing lamp power from 6 to 125 watts at one hour, the degradation efficiency increased by 24.5%, 23.5%, and 29.7% at concentrations of 10, 30, and 50 mg/l, respectively. Also, by increasing time from 5 to 15 minutes under the 125-watt radiation, the removal efficiency increased from 45.6 to 96.8%. Examining the results of mass gas chromatography revealed that atrazine photolysis process progressed towards the mineralization of atrazine. Accordingly, organic chlorine transformed to chlorine ion and organic nitrogen involved in ammonium and nitrate molecules. Conclusion: Overall, the results indicated that photolysis at the wavelength of 254 nm could be used along with other purification methods to completely remove atrazine and simultaneously disinfect contaminated water sources.