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
Hossein Ali Rangkooy, Behzad Fouladi Dehaghi, Maedeh Kamalvandi, Hojatollah Kakaei,
Volume 14, Issue 3 (10-2024)
Abstract
Introduction: Exposure to various chemicals can occur in the workplace. Polycyclic aromatic hydrocarbons (PAHs) are among these compounds. The aim of this study was to investigate the relationship between exposure to PAHs and urinary metabolites among built-up roofing installers.
Material and Methods: The current case-control study, conducted in 2021 in Ilam City, involved 35 built-up roofing workers as the case group and 15 non-exposed workers as the control group. In this study, in addition to the workers’ respiratory area, samples were taken from the urine to determine the amount of PAHs metabolites. HPLC was used to analyze the samples. The collected data were analyzed using SPSS software version 22.
Results: The mean concentrations of PAHs including naphthalene, phenanthrene, fluorne, pyrene, benzo(a)pyrene, benzo (ghi)perylene and indeno 1,2,3 cd pyrene were 440.26±80.07, 70.49±24.36, 15.18±5.98, 31.21±10.36, 2.15±1.41, 2.25±0.07 and 1.18±0.06 ng/m3, respectively, in respiratory area of the workers. Also, the average level of compounds 1- naphthol, 2- naphthol, 2-hydroxyfluorene, 3-hydroxyfluorne, 1-hydroxyfenanterol, 2+3-hydroxyfenanterol and 1- hydroxypyrene, present in the urine of the population, was obtained equal to 2±1.02, 6.03±2.5, 0.18±0.15, 0.14±0.1, 0.19±0.08, 0.04±0.02 and 0.34±0.26 μg/g creatinine, respectively. Statistical test showed that the values of these compounds were significantly different in the two groups (p <0.05).
Conclusion: Estimating the concentration of aromatic hydrocarbons in the respiratory area of built-up roofing workers showed the noticeable exposure to these compounds, although lower than the allowable limits. However, due to the high carcinogenic nature of these compounds, it is recommended to use appropriate personal protective equipment such as respirators and appropriate work outfits in addition to the technical strategies to combat the exposure.
Hossein Ali Rangkooy, Mojtaba Seraji, ,
Volume 15, Issue 1 (3-2025)
Abstract
Introduction: One of the most common pollutants in industrial and confined environments is toluene. Toluene can be removed in various ways. The simultaneous and integrated use of two methods—adsorption and photocatalytic degradation—in a single process is an important innovation in the removal of gaseous toluene. The aim of this study is to determine the efficiency of a synthesized reduced graphene oxide/carbon nanotube/titanium dioxide (RGO/CNT/TiO2) nanocomposite aerogel in the photocatalytic degradation and adsorption of toluene vapors.
Material and Methods: In this study, RGO/CNT/TiO2 and RGO/TiO2 aerogels were prepared using a one-pot hydrothermal self-assembly method. The properties of the photocatalytic aerogels were investigated using BET testing, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). Aerogels were loaded on a substrate in a photoreactor with two UV-C lamps using dynamic flow. Adsorption efficiency was measured when irradiation was off, and photocatalytic degradation efficiency was measured when irradiation was on using an instantaneous reading device.
Results: Adding CNTs to RGO/TiO2 affects the specific surface area (SSA) and the porous structure of the aerogels. During the processes of adsorption and photocatalytic degradation using RGO/CNT%5/TiO2, the concentration of toluene vapor pollutant decreased from 20 ppm to 3.4 ppm, indicating an efficiency of 81%. In contrast, RGO/TiO2 demonstrated an efficiency of 43.41%.
Conclusion: The results demonstrated that adding CNTs to RGO/TiO2 aerogel significantly improves photocatalytic performance for the degradation of toluene vapor. This enhanced performance is attributed to increased light absorption, an improved electron and hole recombination rate, as well as the facilitation of electron transition from titanium nanoparticles to the graphene structure.
