Showing 3 results for Benzene
Mahta Fooladi, Roxana Moogouei, Seyed Ali Jozi, Farideh Golbabaei, Golnaz Tajadod,
Volume 11, Issue 3 (9-2021)
Abstract
Introduction: Phytoremediation is one of the available techniques for removing the volatile organic compound from the air. Benzene and toluene are volatile organic compounds that exist in many occupational environments. Plants are able to reduce benzene and toluene in the air and the use of plants is a simple and consistent solution for the nature to reduce these compositions in the air and improve the air quality of work environments. The phytoremediation potential of Dannae racemosa and Hedera helix were evaluated for remediation of benzene and toluene in air.
Material and Methods: Dannae racemosa and Hedera helix were exposed to exposed benzene(250ppm) and toluene(250ppm) each time alone in a chamber and to examine the decrease amount of benzene and toluene during 6 days. Then plants were exposed to 250ppm and 250ppm of benzene three times with a rest day and the processes of reduction were investigated.
Results: Dannae racemosa was able to remove all of benzene and toluene concentrations from the air after 6 days. Hedera helix was able to reduce all of benzene and toluene concentration from the air after 6 and 5 days, respectively. The differences in Benzene and toluene remediation were assessed between the first and the third subsequent exposure and the results showed that the reduction rate increased for Dannae racemosa.
Conclusion: It can be concluded that the Dannae racemosa and Hedera helix could be used for benzene and toluene phytoremediation.
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
Saleh Qahri Saremi, Nabiollah Mansouri, Mahmoud Heidari, Marzieh Shekarriz, Homayon Ahmad Panahi,
Volume 15, Issue 2 (7-2025)
Abstract
Introduction: Evaluation of air pollutants using green microextraction methods that do not require solvents and allow for sampling and analysis in a single step has received attention. In this study, the needle trap microextraction method was developed and the hydroxyl fullerene adsorbent was used for benzene sampling in air.
Material and Methods: Needle traps of identical length were filled with the selected adsorbent, and a standard chamber was used to generate specific benzene concentrations for sampling. Subsequently, the variables influencing the performance of the needle trap—specifically, sampling and desorption parameters—were optimized to achieve maximum efficiency using response surface methodology and Design Expert 11 software. Finally, the efficiency of the developed method was evaluated in a real-world environment and compared with the NIOSH 1501 method.
Results: Sampling temperature and humidity had an inverse relationship with the peak response rate, such that the sampler performed better at low temperature and humidity. The adsorbent’s ability to retain the analyte, despite its high vapor pressure, was deemed satisfactory, with analyte loss after 5 days measured at 5%. The maximum desorption occurred at 275°C and 3 minutes. The instrumental and quantitative detection limits were calculated to be 0.011 µgL-1 and 0.029 µgL-1 of air, respectively. The relative standard deviation (RSD) as an indicator of the repeatability of the method under study was also 5.38%. In a comparative study, the performance of the needle trap was evaluated to be better than the NIOSH method.
Conclusion: The needle trap method and the hydroxyl fullerene nanostructure adsorbent have a good performance in sampling benzene in air and are recommended for occupational and environmental monitoring.
