Showing 7 results for Filtration
Majid Habibi Mohraz, Farideh Golbabaei, Il Je Yu, Asghar Sedigh Zadeh, Mohammad Ali Mansournia, Somayeh Farhang Dehghan,
Volume 8, Issue 1 (4-2018)
Abstract
Introduction: Electrospun nanofibers are suitable option to synthesize filtering mats for nanoparticles. This study was aimed to fabricate polyurethane nanofiber mats through electrospinning process and to investigate the effect of different parameters such as packing density, face velocity and particle type on the filtration efficiency and quality factor of electrospun polyurethane nanofiber mats.
Material and Method: The nanofiber mats were produced by electrospinning process. Polyurethane granules were dissolved (15w/w%) in a solvent system consisting of dimethylformamide and tetrahydrofuran (3:2). Then, the filtration performance testing system was made at the Fluid Mechanics Department of Hanyang University of South Korea and the filtration efficiency and pressure drop of prepared nanofiber mats were studied.
Result: Findings showed that by increasing the duration of electrospinning, the basis weight, thickness, packing density, initial pressure drop and filtration efficiency of the mats increased, and the quality factor of the mats decreased due to the increase of the pressure drop. The increase in electrospinning duration from 15 to 45 minutes was led to the increase in pressure drop from 7 to 32 Pa and the average filtration efficiency was increased about 9-10% for KCl and DEHS test particles. The filtration efficiency and quality factor of the prepared polyurethane nanofiber mats were declined with the increase of filtration face velocity from 2 to 5 and 10 cm/s. The reduction in filtration efficiency was more obvious for particles smaller than 425 nm.
Conclusion: The results demonstrated that prepared polyurethan naofiber mats provide acceptable filtration performance. What is more, such nanofiber mats can have other potential benefits such as light basis weight, low thickness and simple production.
Zahra Alaei, Roohollah Ghasemi, Mohammad Reza Pourmand, Ali Karimi, Ensieh Masoorian, Farideh Golbabaei,
Volume 12, Issue 2 (6-2022)
Abstract
Introduction: Volatile organic compounds are the most common pollutants in the air, and among them, toluene is the most common form, which is toxic resulting in liver and kidneys damages. Regarding the fact that this compound is widely used in various chemical industries, implementing an efficient method for controlling its concentration is of great importance. The comparative survey of the capability of virgin activated carbon with the one immobilized by pseudomonas putida PTCC, and also the performance of the biofiltration system involving pseudomonas putida bacteria immobilized on activated carbon for the adsorption and degradation of toluene from the air as well as regenerating the activated carbon were aimed in the present study.
Material and Methods: The microbial growth process was initiated by incubation of pre-culture in a rotary shaker, at 150rpm overnight. After 4 days, the strain pseudomonas putida, PTCC No: 1694 was immobilized on a certain amount of activated carbon. Subsequently, an airstream containing toluene was introduced into the biofilter, and the inlet and outlet concentrations of toluene were measured.
Results: The obtained results illustrated that the increase in the volume of the media and decrease in the gas flow rate significantly enhances efficiency. The great performance of the biofilter was confirmed by the high efficiency of the immobilized activated carbon which exhibited 89% yield during 14 hours. On the second cycle, the biofiltration system was able to adsorb toluene at an efficiency of 81%, while the virgin activated carbon exhibited far less efficiency with the value of 28%.
Conclusion: The provided results demonstrated the feasibility and reusability of the biofilter system for toluene removal. The proposed technique also extends the activated carbon’s capacity, which could be a potential solution to re-use the activated carbon in industrial applications.
Meghdad Kazemi, Saba Kalantari, Alireza Abbasi, Abbas Rahimi Foroushani, Hossein Mowlavi, Amir Hossein Montazemi, Farideh Golbabaei,
Volume 13, Issue 1 (3-2023)
Abstract
Introduction: In recent years, the manufacture of air purification media, especially nanofiber filters using polymeric materials and the electrospinning method, has received much attention in air pollution control. The production of high-performance media and low-pressure drops is an important issue in air filtration. This study aimed to investigate the feasibility of fabricating electrospinning polyethylene terephthalate (PET) media to abduct submicron and micron particles from the air stream.
Material and Methods: To determine the optimal device conditions in the manufacture of PET media, different weight percentages of a PET polymer solution in a mixture of trifluoroacetic acid and dichloromethane solvents (70:30) were first prepared in a pilot study, and various parameters of the electrospinning device were examined and analyzed along with performing the electrospinning process. The surface and morphological characteristics of the media were evaluated using SEM. The pressure drop and efficiency of particle trapping were assessed using a mask and media pressure by a pressure drop test device.
Results: The optimal electrospinning conditions of the PET polymer solution were obtained at a concentration of 20%. The average diameter of nanofibers PET was 163 ± 600 nm with a pressure drop of 26.33 ± 5.5 pa, and average efficiencies of 97.42 ± 1.67% and 99.85 ± 0.21 were obtained for submicron and micron particles, respectively, with a quality factor (QF) value of 0.1740.
Conclusion: The produced media can abduct and remove particles from the air stream for submicron and micron particles in ranges of 96-99% and 99-100%, respectively, with an average pressure drop of 26.33±5.5 pa.
Siavash Azad, Yousef Rashidi, Farideh Golbabaei,
Volume 13, Issue 2 (6-2023)
Abstract
Introduction: The important parameters for evaluating the performance of particle filtering respirators in international standards are the filtration efficiency and respiratory resistance of the mask filter against airflow passage. To improve nanofiber filtration efficiency while creating the least breathing difficulty for the wearer, various research has been or is being conducted worldwide. This study investigated the effect of using polyacrylonitrile (PAN) nanofiber composite membrane and montmorillonite clay nanoparticles (MMT) in enhancing particle-filtering respirators’ filter performance, achieving higher filtration efficiency while maintaining optimal respiratory resistance conditions.
Material and Methods: First, PAN polymer solution containing zero, 1%, 2%, 3%, and 5% MMT nanoparticles was prepared, and then PAN/MMT nanofiber composite membrane was synthesized in an electrospinning machine. Filtration efficiency was measured in diameter range of 0.3, 0.5, 1, and 3 microns using sodium chloride aerosol. Additionally, filter breathing resistance was measured at flow rates of 30, 85, and 95 liters per minute.
Results: The efficiency of synthesized composite nanofilters for particle purification can be improved by adding MMT nanoparticles to PAN nanofibers. Optimal MMT concentration was found to be 2%. This addition resulted in an increase in filtration efficiency for particles with sizes of 0.3, 0.5, 1, and 3 microns by 4.2%, 4.88%, 3.77%, and 2.75% respectively without causing significant difference in respiratory resistance. Improved filtration efficiency can be attributed to enhanced morphology of composite nanofilters resulting from addition of MMT nanoparticles. Adding 2% MMT nanoparticles to PAN nanofibers resulted in uniform distribution and smaller fiber dimensions which did not significantly affect Packing density and porosity.
Conclusion: If 2% of MMT nanoparticles are added to PAN nanofibers and used to produce particle respirators, resulting respirator will exhibit a 4.2% increase in particle filtration efficiency without increasing breathing difficulty for user. This result can help protect users from particulate pollutants in air pollution conditions.
Saba Kalantary, Mohammad Reza Pourmand, Ensieh Masoorian, Mirghani Seyd Someah, Zahra Barkhordarian, Sara Hajinejad, Farideh Golbabaei,
Volume 14, Issue 2 (6-2024)
Abstract
Introduction: Protection of the respiratory system has been a vital, and for this purpose, various solutions have been proposed, including the use of masks. One of the most important parameters to measure the effectiveness of the mask against the penetration of microbial agents. The present study was conducted with the aim of evaluating the bacterial and particle filtration of medical masks.
Material and Methods: To assess bacterial performance, the national standard 6138, compliant with EN14683, and Type I medical masks were utilized. Staphylococcus aureus bacterial suspension was prepared and passed through the mask using a nebulizer and through an impactor with a flow rate of 28.3 l/min. Plates containing soy agar were placed in the impactor. Subsequently, all plates were incubated, and the bacterial filtration efficiency (BFE) of the masks was determined by counting the bacterial colonies that passed through the mask’s media as a percentage of the total bacteria. It is worth noting that the pressure drop and particle filtration efficiency were also determined for all masks
Results: Based on the results of the particle removal performance for the particle size of 3 µ, the masks were categorized into three groups with efficiency above 99%, above 95% and 90%. According to the standard, all masks had an acceptable pressure drop below 40 Pa. The acceptable bacterial filtration rate for type I masks should be above 95%. The results showed that type A and B masks have an acceptable bacterial filtration rate and there is a significant correlation between the types of masks examined in terms of bacterial and particle efficiency.
Conclusion: The results showed that different types of masks under investigation have significant differences in terms of particle capture efficiency and bacterial filtration performance. In addition, there is a significant correlation between bacterial and particle filtration efficiency.
Mehrdad Helmi Kohnehshahri, Farideh Golbabaei, Somayeh Farhang Dehghan, Rezvan Zendehdel, Alireza Abbasi, Zahra Yadegar,
Volume 15, Issue 2 (7-2025)
Abstract
Introduction: With the advancement of industries and increased use of metalworking fluids, controlling pollutants generated by machining operations has become increasingly challenging. This study aimed to address these challenges by designing an air filtration system designed specifically for this purpose.
Material and Methods: A local exhaust ventilation system was developed based on the VS-80-12 ACGIH standard, tailored to the working conditions and air sampling of the environment. The filtration system includes an aluminum pre-filter, an E11 class filter, and a nanofiber filter incorporating a metal-organic framework. The performance of the system was evaluated by measuring the numerical concentration of particles and the mass concentration of oil mist at both the inlet and outlet. The results were then compared to those obtained from an E1 class filter.
Results: The results obtained from XRD and FTIR analyses showed that ZIF-8 had high crystallinity and was successfully incorporated into the structure of the fibrous media filter containing metal-organic framework. The evaluation revealed that the filtration system effectively removed pollutant particles at their source. Notably, the initial efficiency for larger particles reached 100%, while the average removal efficiency for particles smaller than 2.5 microns was 99%.
Conclusion: In conclusion, the combination of nanofiber filters with a metal-organic framework and aluminum pre-filters presents an effective solution for controlling particulate pollutants from machining operations. However, further research is necessary to comprehensively assess the system’s performance, particularly regarding dust loading capacity. Future studies should also explore the effects of various factors, such as airflow rate and the type of metalworking fluid, on the system’s efficacy.
Sepideh Keyvani, Farideh Golbabaei, Rasoul Esmaeely Neisiany, Saba Kalantary, Oisik Das, Abbas Rahimi Foroushani,
Volume 15, Issue 4 (12-2025)
Abstract
Introduction: Polymer nanofiber filters have great potential for controlling particulate pollution due to their high filtration efficiency and low pressure drop. This study aimed to fabricate nanofiber membranes from a biodegradable polymer through solution electrospinning to address both health and environmental concerns, along with analyzing their morphological characteristics. The filtration performance of the prepared membranes was evaluated against different particle sizes under two air face velocities.
Material and Methods: The nanofiber membranes were fabricated from aqueous poly(vinyl alcohol) (PVA) solutions at various concentrations from 5 to 6 w/v% under different process parameters. The morphological characteristics of the nanofibers were examined using field-emission scanning electron microscopy (FE-SEM), while structural properties such as basis weight and thickness were measured to estimate porosity. Filtration performance, including efficiency and pressure drop, was evaluated at two standard air face velocities (2.5 and 5.3 cm/s) using a media test system. In addition, the quality factor of the prepared membranes was calculated.
Results: The electrospun nanofibers were uniform and bead-free, with the mean fiber diameters ranging from 106 to 151 nm. The filtration efficiencies were 95.72–99.92 % for sub-micron particles (0.3 and 0.5 µm), and 99.43–100 % for larger particles (1 and 3 µm). The pressure drop ranged from 67 to150 Pa at an air face velocity of 2.5 cm/s, and from 58 to150 Pa at an air face velocity of 5.3 cm/s.
Conclusion: The 6 wt.% PVA nanofiber membrane electrospun at 15 kV, 0.5 mL/h, and 15 cm produced thinner fibers (approximately 106 nm) and exhibited higher efficiency for 0.3 µm particles (99.89 % and 99.92 % at 2.5 and 5.3 cm/s air face velocities, respectively). For this membrane with thinner fibers, the pressure drop increased from 67 to 150 Pa with rising the air face velocity.
