Showing 3 results for Zeolite
F. Golbabaei, E. Rahmanzadeh, G. R. Moussavi, A. Faghihi Zarandi, M. R. Baneshi,
Volume 4, Issue 2 (7-2014)
Abstract
Introduction: Chromium (VI) is a known human carcinogenic agent which is used in numerous industrial processes such as electroplating, welding, textile, cement and steel fabrication. The aim of this study was to determine the effectiveness of natural zeolite on the fixed bed adsorption of Cr (VI) from air stream.
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Material and Method: In this experimental study, chromium mists were generated by a nebulizer (3A model, Italy). Performance of natural zeolite in the Cr (VI) adsorption and its influencing factors such as air flow rate (1 and 3 L/min), the initial Cr concentration (0.05, 0.15, 1 and 10 mg/m3) and the bed depth (2.5, 5 and 10 cm) were investigated.
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Result: Zeolite adsorption capacity elevated by the increasing of bed depth but decreased with increasing of flow rate and inlet concentration. In order to facilitate the prediction of natural zeolite column performance Yoon-Nelson and Thomas models were used. The results showed that these models have a good agreement with our experimental data.
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Conclusion: Due to the extensive use of chromium in various industries and regulatory requirements related to workplace health and safety, Cr emission control in the occupational environment is essential. The adsorption process is one of the controlling measures of chromium emissions. The results indicated that natural zeolite has a high efficiency in Cr (VI) adsorption.
Hasan Iravani, Mohammad Javad Jafari, Rezvan Zendehdel, Soheila Khodakarim, Athena Rafieepour,
Volume 10, Issue 1 (3-2020)
Abstract
Introduction: Hydrogen sulfide (H2S) is a toxic gas that has adverse effects on human health and equipment. One of the methods for eliminating of H2S gas is the use of adsorbent substrate. In this study, the effect of adding iron oxides including ferric (Fe2O3) and magnetite (Fe3O4) nanoparticles to ZSM-5 zeolite substrate was investigated on the efficiency of H2S elimination from the air stream.
Methods: In this study, Fe2O3 and Fe3O4 nanoparticles were impregnated in ZSM-5 zeolite in two weight ratios of 3% and 5%. The structural properties of the substrate were studied using XRD, BET and SEM. Then, the efficiency of substrate in removing H2S from air was studied while H2S gas was injected in to a pilot setup, in concentrations of 30, 60, 90 and 120 ppm at three bed temperatures of 100, 200 and 300 o C.
Results: The accuracy of combination and the morphology of inoculated zeolite was confirmed using XRD and SEM. The BET test also showed that the loading of iron oxide nanoparticles on the substrate educed the substrate surface area. The results revealed that increasing the percentage of nanoparticles and increasing the temperature from 100 ° C to 300 ° C increase the time of breakthrough point. The maximum adsorption capacity was obtained equal to 44.449 (mgH2S/g zeolite) for ZSM-5/Fe3O4-5% substrate at 120 ppm concentration.
Conclusion: Iron oxide nanoparticles inoculated in ZSM-5 zeolite substrate increase the capability of eliminating of H2S gas at high temperatures and therefore can be used as a suitable method for the elimination of similar pollutants.
Hosseinali Rangkooy, Maryam Mosavi Ghahfarokhi, Behzad Fouladi Dehaghi,
Volume 11, Issue 4 (12-2021)
Abstract
Introduction: Ethylbenzene is a volatile organic compound used in many industries, including oil and gas, oil colored and insecticides. Due to the toxic effects of this chemical substance, control and elimination of this vapor is necessary. Photocatalytic degradation is a possible method to remove organic compounds from air. This study was performed to determine the efficiency of photocatalytic removal of ethylbenzene vapor using ZnO nanoparticles immobilized on modified natural zeolite.
Material and Methods: Natural zeolite was first modified with hydrochloric acid and then with diphenyl dichlorosilane. Next, zinc oxide nanoparticles were stabilized on the zeolites. Dynamic air flow and different concentrations of ethyl benzene (25, 50, 100 and 200 ppm) were produced and the removal efficiency of ethylbenzene vapor was investigated using UV/MZe/ZnO. The temperature and relative humidity were set at 25±2°c and 35%. The surface and volume of the pores of the bed were determined by the BET method and surface structure was determined by Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD).
Results: Evaluations for BET showed the specific surface areas decreased by increasing the amount of ZnO. XRD analysis and SEM images showed that zeolite structure was stabled and nanoparticles was successfully stabilized on Ze. The results showed that the highest removal efficiency (50.8%) by the process of UV/MZe/ZnO at concentration 25 ppm.
Conclusion: The result of this study showed that the Ze/ZnO catalyst may be an applicable and hopeful method to removal of ethylbenzene from air flow under UV irradiation
