Showing 7 results for Benzene
H Khorsandi, A Mohammadi, F Kariminejad, M Haghighi, R Alizadeh,
Volume 7, Issue 4 (1-2015)
Abstract
Background & Objectives: Entering LAS through the wastewater plant’s effluent to water resources causes taste and odor changes, aquatics death, oxygen transfer limitation, and disorders in water treatment processes. Therefore, the study objective was to determine optimum conditions for fenton oxidation process to remove linear alkyl benzene sulfonate from aqueous environments using taguchi method and its requirement evaluation for additional treatment of Biolac effluent. Materials &Methods: LAS removal using Fenton oxidation was evaluated in a 500 mL laboratory-scale batch reactor. In order to save the costs, to determine the optimum conditions of the Fenton oxidation, 25 runs were computed using Taghuchi method by Minitab 16 software. Sampling and required tests were performed based on standard methods examination for water and wastewater. For evaluation of Biolac process sufficiency in LAS removal, biolac efficiency in Urmia Wastewater Treatment Plant was studied in 2012. Results: Based on the LAS removal and chemicals required, Minitab software (Ver. 16) recommended the optimum conditions of Fenton oxidation at 900 mg/L H2O2, 170 mg/L Ferrous ion, pH of 4, and reaction time of 20 minutes. It was found that the Fenton oxidation for LAS removal had 86.5% efficiency under optimum condithions and it was second order reaction with the rate coefficient of 0.0152 L/mg.min. Biolac process does not need any additional treatment due to meeting LAS standard in municipal wastewater treatment. Thus, this process decreased annually mean LAS from 5.28 mg/L to 0.734 mg/L in municipal wastewater. Conclusion: Although the Fenton oxidation appears as a chemical process with high efficiency in the removal of LAS, the low efficiency of COD corresponding to the LAS indicated partial decomposition of linear alkyl benzene sulfonate by Fenton oxidation.
M Malakootian, A. H Mahvi, H Jafari Mansoorian, M Alizadeh, A.r Hosseini,
Volume 8, Issue 2 (8-2015)
Abstract
Background and Objective: Phenol and phenol derivatives in industrial wastewater are among the pollutants with priorities. The high cost and low efficiency of some routine treatment processes of industrial wastewater has limited their use. One of the new methods under consideration is, nowadays, adsorption using carbon nanotubes. This study was conducted in order to evaluate the application of alumina-coated multiwall carbon nanotubes in eliminating phenol from synthetic wastewater. Materials and Methods: This study was performed in laboratory at batch scale. Multi-wall carbon nanotubes were coated with Alumina. The concentration of phenol was determined by spectrophotometer through photometry. The effect of pH changes, dosage of adsorbent, contact time, the initial concentration of phenol, temperature, and the concentrations of different salts on the efficiency of absorption was evaluated. Then, the absorption results were described using the Langmuir and Freundlich isotherms and the synthetics of absorption. Results: It was found that absorption efficiency increased significantly by decreasing the initial concentration of phenol and pH and by increasing the carbon nanotube dosage, temperature, and contact time. On the other hand, the maximum elimination of phenol from the solution (98.86%) occurred at 4 mg/l phenol concentration, under acidic conditions (pH=3), at adsorbent dosage of 0.05 g/l, at temperature of 45°C, and contact time of 10 min. Evaluation of the regressions isotherms showed that the process follows the Langmuir model and second-degree synthetic absorption. Conclusion: The high efficacy (98%) of the adsorption process in this study showed that alumina-coated multiwall carbon nanotubes have a good capability in eliminating phenol and can be used as an appropriate and new method for eliminating phenol and its derivatives from wastewater.
N Rastkari, F Izadpanah, M Yunesian,
Volume 8, Issue 2 (8-2015)
Abstract
Background and objective: Benzene is one of the main pollutants in air and one of the most extensive chemical compound used in both natural and industrial processes. Benzene exposure leads to the most dangerous adverse health effects, particularly blood cancer. The aim of this study was to evaluate the gas station workers’ exposure to benzene by measuring benzene in breathing air and urinary trans, trans-muconic acid. Materials and Methods: This cross-sectional study conducted in summer 2014 investigated 40 gas station workers and 40 occupationally non-exposed persons. Spot urine samples were obtained prior to and at the end of the work shift from each subject. The urinary levels of trans, trans-muconic acid was determined by liquid chromatography (HPLC) with diode array detector. At the end of the work shift, the benzene collected on sorbing cartridges was desorbed using carbon disulfide and was analyzed using gas chromatography and mass spectrometry detection. Results: The mean value for exposure to benzene in breathing zone of gas station workers was 5.90 ±1.93 ppm, which was significantly greater than the occupationally non exposed group (1.15±0.744 ppm). The mean urinary concentrations of trans, trans-muconic acid differed significantly between samples of gas station workers (64.75±19.47 µg/L) and occupationally non-exposed persons (47.10±13.67 µg/L). Conclusion: A good correlation (r = 0.581) between the mean values of benzene in breathing zone and the urinary concentration trans, trans-muconic acid was observed. Gas station workers were found to be probably the most exposed groups in this study. Inhalation is presumably the main route of exposure in gas station workers.
M Zare Jeddi, M Yunesian, R Ahmadkhaniha, H Kashani, N Rastkari,
Volume 8, Issue 3 (12-2015)
Abstract
Background and Objective: One of the air pollutants is volatile organic compounds (VOCs). Benzene, as a part of petrol, is a VOC, known to be carcinogenic to human beings (Group 1) and it has widespread application in various industries and professions. Hence, the aim of the present study was semi-quantitative and quantitative health risk assessment of petrol bank workers exposure to benzene via inhalation in the Tehran, Iran.
Material and method: For these purpose, this descriptive cross-sectional study was conducted in three stages. First stage consisted of measurement of benzene in two groups of participants: (1) petrol bank workers and (2) non-exposed people as control group. The second stage included the evaluation of worker's exposure to benzene and semi-quantitative risk assessment, and the third stage was estimating the lifetime cancer risk caused by exposure to benzene.
Results: Benzene mean concentration was near the threshold limit value (1600 µg/m3) and the mean benzene personal air level was 1527±246.4 µg/m3 in the petrol bank areas. With regard to semi-quantitative risk assessment method, benzene introduced as the most hazardous chemical with risk ratio of 4.5 has 5th rank in risk levels (Extremely dangerous). Lifetime cancer risk estimation showed that in petrol bank workers the excess lifetime cancer risk was 27.5 times higher than unexposed group and the chance of cancer was one in a 1000 petrol bank workers.
Conclusion: This study indicates that petrol bank workers in Tehran have a potentially high cancer risk through inhalation exposure. Thus, preventative actions regarding to this hazardous and carcinogenic chemical must be started as soon as possible.
E Hoshyari, N Hassanzadeh, A Charkhestani,
Volume 12, Issue 1 (5-2019)
Abstract
Background and Objective: Nowadays linear alkyl benzene sulfanate (LAS) is widely used in the production of various detergents. The purpose of this study was to assess the health and ecological hazards of this pollutant on target organisms such as fish and daphnia in the Doroodzan Dam water.
Materials and Methods: According to the research objective and given existing restrictions, 21 water samples were collected in September 2018 from 7 selected stations based on the source of contamination in Doroodzan dam. Water quality parameters including pH, Dissolved Oxygen (DO), potential Redox (ORP), Total dissolve solid (TDS) and Electrical conductivity (EC) was measured at the site. The amount of linear alkyl benzenesulfonate (LAS) was measured using an optimized methylene blue method after transferring samples to the lab. Then ecological and health risk assessment was performed by calculating the RQ index (risk index).
Results: The results showed that the mean of pH, EC, TDS, salinity and DO were 8.88, 732.19 µs/cm, 482.49, 366.16 and 6.87 mg/L, respectively. The highest and lowest concentrations of LAS were 0.039 and 0.055 mg/L, respectively. The results also showed that there is a significant relationship between LAS concentration and pH. The results of the risk assessment showed that the health risk index in all stations is less than 0.1, while the ecological risk index except at station 7, are in low risk level.
Conclusion: In general, the results show that the RQ index in the Droodzan Dam water is in appropriate range and in the low risk level. Therefore, it is necessary to conduct long-term studies in this field to ensure the persistence of optimal water conditions in the dam ecologically and health-wise.
Farzaneh Borzabadi Farahani, Mahmood Alimohammadi, Jamshid Rahimi, Sanaz Khoramipour, Emad Dehghanifard,
Volume 18, Issue 2 (9-2025)
Abstract
Background and Objective: People spend over 90% of their time indoors, where air pollutant concentrations—including volatile organic compounds (VOCs)—are significantly higher than outdoors. Among these VOCs, benzene is particularly critical due to its carcinogenic properties. Phytoremediation offers a sustainable solution for removing such pollutants from indoor environments. This study evaluates the benzene-reduction efficiency of two ornamental plant species, Aglaonema ‘Silver’ and Chlorophytum comosum, under controlled temperature and humidity conditions.
Materials and Methods: The plants were exposed to two temperature levels (18°C and 24°C) and two relative humidity conditions (35% and 50%). Benzene was introduced into sealed chambers at concentrations of 1, 0.5, 0.25, and 0.125 µL/mL. After 12 hours of exposure, benzene reduction was quantified using gas chromatography.
Results: At 20°C and 35% RH, Aglaonema 'Silver' removed 96% of benzene, outperforming Chlorophytum comosum (38%). Removal efficiency depended on species, environmental conditions, and initial concentration. Predictive models (Eq. 2–3) correlated strongly with experimental data (R² > 0.9).
Conclusion: Aglaonema 'Silver' demonstrated superior benzene removal compared to Chlorophytum comosum under lower temperature and humidity conditions. Our findings highlight that selecting plant species adapted to specific environmental parameters can significantly improve phytoremediation effectiveness. Furthermore, the proposed model indicates that elevated temperature and humidity levels may enhance benzene removal efficiency by indoor plants.
Ramazanali Dianati Tilaki, Roghayeh Kaseb, Esmaeil Babanejad Arimi, Mohammad Dianati,
Volume 18, Issue 3 (12-2025)
Abstract
Background and Objective: Benzene is a carcinogenic volatile organic compound commonly found in polluted air. This study aimed to remove benzene from air using a TiO₂–Bi2O₃ composite photocatalyst immobilized on glass foam under ultraviolet (UV) light irradiation.
Materials and Methods: Glass foam coated with the TiO₂– Bi2O₃composite was placed in a quartz reactor, which was connected to an air pump inside a sealed glass chamber. A UV lamp (254 nm) was installed next to the reactor. Known volumes (µL) of benzene were injected into the chamber through a septum. When the pump was activated, benzene-contaminated air passed through the photoreactor. Benzene concentration was measured by collecting air samples from the chamber and analyzing them using a GC-FID device.
Results: XRD spectra and SEM images confirmed the presence of TiO₂ and Bi2O₃, while BET analysis verified the mesoporous structure of the composite photocatalyst. The surface adsorption of benzene by the composite was 15% and followed the Langmuir model. The process kinetics were first-order, and the removal efficiency decreased with increasing benzene concentration. At a benzene concentration of 39 ppm, the removal efficiency after 75 minutes of TiO₂ and UV irradiation was 75%, whereas for TiO₂– Bi2O₃ under similar conditions, the efficiency increased to approximately 90%.
Conclusion: Using a TiO₂– Bi2O₃ composite photocatalyst under UV-A irradiation improved benzene removal efficiency by about 15% compared with TiO₂alone.
