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Introduction: Toluene is significant pollutants in the air. Long-term exposure to toluene can lead to adverse effects. Biofiltration is one of the air pollutant control methods. In this study, Pseudomonas putida was selected as a microorganism capable of hydrocarbon degradation and its ability to biodegrade toluene in a suspension growth reactor was also investigated. Material and Methods: Experiments were conducted in two days and in five hours. Each method consisted of three sample reactors (A, B, C) and one control reactor (D). In the first method, the amount of bacteria in the sample reactors is 0.5, 1 and 2 McFarland and the amount of toluene injection into the reactors is the same (0.5 microliters) and in the second method, the amount of toluene injection into the sample reactors is 0.5, 1 and 1.5 microliter and 1.5 microliter in the control reactor and the amount of bacteria in them was the same (1 McFarland).Toluene gas samples and carbon dioxide were periodically analyzed. Results: In the first method of toluene decomposition, there was a significant difference between the three reactors (p-value = 0.002). The results of the second method were also significantly different between the three reactors (p-value

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.

Abstract With increasing concerns about industrial gas contaminants and the growing demand for durable and sustainable technologies, attentions have been gradually shifted to biological air pollution controls. The ability of Pseudomonas putida PTCC 1694 (bacteria) and Pleurotus ostreatus IRAN 1781C (fungus) to treat contaminated gas stream with toluene and its biological degradation was compared under similar operating conditions. For this purpose, a biofilter on the laboratory scale was designed and constructed and the tests were carried out in two stages. The first stage, bacterial testing, lasted 20 days and the second stage, fungal testing, lasted 16 days. Inlet loading rates (IL) for bacterial and fungal biofilters were 21.62 ± 6.04 and 26.24 ± 7.35 g/m3 h respectively. In general, fungal biofilter showed a higher elimination capacity (EC) than bacterial biofilter (18.1 ± 6.98 vs 13.7 ± 4.7 g/m3 h). However, the pressure drop in the fungal biofilter was higher than the bacterial biofilter (1.26 ± 0.3 vs 1 ± 0.3 mm water), which was probably due to the growth of the mycelium. Fungal biofiltration showed a better performance in the removal of toluene from the air stream.

Introduction: Air pollution is now recognized as an important environmental and health concern. Biological control processes, due to their durable, cost-effective and eco-friendly, have become a good alternative to physic-chemical methods. Biotechnology is based on the activity of microorganisms. The aim of this study was to compare the capability of Pseudomonas Putida PTCC 1694 (bacteria) and Polarotus Stratus IRAN 1781C (mushroom) in the removal of toluene from the air stream and its biodegradation under same operating conditions. Material and Methods: To this purpose, a bio filter containing two parallel columns was designed and constructed on a laboratory scale and the experiments were carried out based on measuring the removal efficiency (RE), elimination capacity (EC) and pressure drop in these two columns. Thus, the bacteria were inoculated in one of the columns and in the other the fungus was inoculated. Results: The bacterial testing lasted for 20 days and the fungal testing lasted for 16 days. The contaminant loading rates (LR) for bacterial and fungal bio filters were 11.65±2.26 and 11.94±2.56 g/m3.h, respectively. The results showed that the fungal bio filter was more capable of eliminating of toluene vapor than bacterial bio filter (9.65±3.53 vs 9.18±2.6 g/m3.h). However, the pressure drop in the bacterial bio filter was lower than the fungal bio filter (1±0.28 vs 1.1±0.32 cm water). Conclusion: According to the results, fungal bio filtration appeared to be more successful than bacterial bio filtration in the removal of toluene.

The mass-transfer media plays a significant role on the performance of a packed tower. In this paper three counter-current single-stage packed towers at laboratory scale, randomly packed with two different sizes of two types of packing material were experimentally tested to study the role of the packing on the performance of them in the removal of sulfuric acid mists. Gas samples were extracted from specified points and quantified using US EPA method 8. All required steps were taken in order to comply with quality assurance procedures described in US EPA method 8. The results from 98 tests in four series including two types of packing materials each in two packing sizes revealed that 1.27 cm (0.5 inch) Raschig ring and Intalox saddle had higher removal efficiencies (94.0% and 92.3% respectively) than 2.54 cm Raschig ring and Intalox saddle (86.8 and 81.8% respectively). The statistical comparison of the average removal efficiencies showed that there was no significant difference (Pvalue = 0.344) between the average removal efficiency of the tower packed with 1.27 cm Intalox saddle and 1.27 cm Raschig ring. The highest removal efficiency of 98.2% was obtained at Hc/Dc ratio of 3 for 1.27 cm Raschig rings. The highest removal performance versus gas flow rate over packing volume (Qgas/Vpack) ratio was obtained with average removal efficiency of 95.0% for 1.27 cm Raschig rings. It was concluded that 1.27 cm Raschig rings performed the best for removal of sulfuric acid mists from air stream using packed bed caustic scrubbers.

The main focus of detailed discussions in this essay was studying the reasonsthat caused Syria to turn into an important security issue for Iran. Given thelong history of relations between the two, the emergence of this crisis hasactivated Iran heavily and roughly to prevent and confront the West's powersince lagging in this issue will impose heavy prices on the Islamic Republic ofIran. The current essay has studied four important reasons for the securityimportance of Syria to Iran; Syria as a dam against the infiltration of the USanti-Iran policies in the Middle-East, Syria's common borders with Hezbollahand Israel, Syria as a place for adopting ideological defense-invasion strategyand its stance in the confluence point of the Islamic Iran and the Arabnationalism ideologies can be the main elements for forming Iran-Syriansecurity relations. As Iran's ally, Syria can be a key factor in preventing theWest's complete plundering of the region and given the four aforementionedcomponents, it can justify and redefine Iran's all-out support for Syria during thecrisis in the country.