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In this study, BixOyClz/rGO-NiFe2O4 magnetic nanophotocatalyst was synthesized using the hybrid ultrasound-solvothermal method. To compare the BixOyClz/rGO and NiFe2O4 samples were also fabricated. The properties of these nanophotocatalysts were determined using various analyses such as XRD, FESEM, EDX, BET-BJH, DRS and VSM. The results obtained confirmed the correctness of the syntheses. According to the VSM analysis, the saturation magnetization of BixOyClz/rGO-NiFe2O4 nanophotocatalyst was obtained about 3.8 emu/g. Moreover, regarding the BET-BJH results, the total open pore volume and specific surface area of this sample was obtained 0.5 cm3/g and 130 m2/g. Finally, its photocatalytic performance was evaluated in the elimination of the ofloxacin and ciprofloxacin, as antibiotic contaminants, and rhodamine B and acid orange 7, as color pollutants. Results indicated the excellent activity of this nanophotocatalyst. So that, after 180 min, the elimination efficiency was gained at about 98.5, 100, 100 and 96.5% for ofloxacin, ciprofloxacin, rhodamine B and acid orange 7, respectively. These consequences were devoted the decrease of band gap and increasing the light absorption range, improving the separation and transmission of charge carriers and reducing recombination rate of them increasing the surface absorption of contaminant molecules as a result of the presence of rGO and the proper dispersion of BOC due to using of ultrasound waves and the breaking of clusters and the increment of accessible active sites.

One of the most important pollutants that cause air pollution in cities is volatile organic compounds that cause many complications in people. Gasoline pumps as well as cars are among the most important sources that cause the accumulation of these pollutants, and due to the increasing number of cars, gasoline pumps have become a dangerous place that should be taken into consideration. Since air pollution is a very complex process that depends on many factors, it is very difficult and expensive to predict such data, which have nonlinear dynamics. In this research, by collecting experimental data from three gas stations in Zanjan and identifying the influencing parameters, modeling has been done using artificial neural network. That, two multilayer perceptron models and radial basis function were investigated. In the statistical part of this research, the correlation coefficient and the sum of squared errors were used as necessary criteria to measure the accuracy of the two mentioned models. The results and analysis conducted in this study showed that the pollution resulting from the consumption of gasoline includes two stages, one at the time of refueling and the other after refueling. Also, in the summer, the concentration of volatile organic compounds is higher than in the winter, and this amount of pollution is observed more in the morning and evening.

Passenger cars are considered as one of the main sources of air pollution, especially in cities. The large pollutants that are generated from the combustion zone in vehicles, directly and indirectly, can affect the individual and national economy. ‏ In the direct economic losses, the gradual death of green spaces and forests can be opposition to the exposure of pollutants such as nitrogen oxides and ozone, or damage to monuments, objects, and facades of buildings due to corrosion by suspended particulate or matter pollutant compounds‏. to develop respiratory, heart and lung diseases caused by various phenomena of air pollution in public health (Mayer et al., 1999; Jacob et al., 2016). By examining the results from technical examinations and comparing them with the standard of emission in Iran and European countries, it was found that all of the cars reviewed in this paper were consistent with Iranian emission standards, while in comparison to the Euro emission standards they did not have a favorable situation. therefore, the estimation of vehicles emissions, especially the internal vehicles using data collected from technical observation centers, is very necessary and can be achieved by estimating the pollution rate in the planning, reducing the pollution of large cities as well as the prevention of small towns. In fact, if the amount of pollution of vehicles used inside Iran is available, it can be driven by a series of changes in the intended vehicle due to the factors affecting its publication and defining different projects to improve air pollution, as well as the direction of management and control of emissions from vehicles. In recent years, research aimed to investigate the amount of pollutants output, which suggests that, unfortunately, manufacturing cars in terms of environmental standards produce many pollutants (Gulbute et al., 1395). Therefore, in order to determine the exact status of internally produced vehicles, additional research is necessary. The study examined technical examinations, notably technical examinations of passenger cars and the pollution inspection of the seven cars that are very common in Iran. This study is done in East Azerbaijan and Khuzestan province, which are completely different from the climatic point of view, and the results obtained from the two oblasts have been compared.

The adsorption process is one of the important methods of separation in which liquid phase or gas particles are separated by a solid phase called absorbent. The main advantages of adsorbents include high efficiency, low cost and minimization of chemical or biological sludge.

In this study compost as natural and low cost adsorbent is used to remove the heavy metal copper from waste water. At first the influence of parameters such as initial concentration of copper, amount of adsorbent, contact time at constant flow rate on the adsorption process was checked in batch system. Removal efficiency of Cu2+ ions with initial concentration of 100 ppm in constant amount of adsorbent was more than 90%.

The results indicated that compost has a very good performance for the removal of copper. To analyse the isotherm of Cu2+ adsorption onto compost different models were applied. The Cu2+ ions adsorption onto compost was better defined by the Freundlich model. Evaluation of the performance of adsorption process in continuous system showed that that maximum efficiency is related to the time that 25% of the remaining columns were filled by granular compost and the rest was filled by powder compost. Also with increasing concentrations of copper, the metal removal rate increased. It was also observed that the time of the process leading to increased removed so that at this system the removal after 15 minutes for all concentrations reached up to 100%.

The results showed that by using compost as adsorbent agent, more than 90% of copper metal can be removed at aqueous solutions. Also, by calculating the separation coefficient based on Langmuir isotherm, it is observed that the separation coefficient for compost used is in the range of 0 to 1, and this indicates the desirability of the adsorbent.

Dez River as the main source of water for agriculture, industry and drinking have particular importance in the north of Khuzestan plain. Dez River passes from different areas such as village and industrial cities, it is possible to enter many contaminants. So, water quality studies can be very useful. In this study, samples from 14 stations in the north of Khuzestan plain in three periods (low rainfall, medium and high) and analysis of anions and cations, heavy metals and the pH of water and measuring hardness, conductivity electric and total dissolved solids, calculating the evaluation index of water such as saturation index, permeability index, the percentage of soluble sodium, sodium adsorption rate and using charts Wilcox, Piper and stellar and compared to irrigation water standards; regional water situation was evaluated. Finally were determined characteristics of water at each station and the restrictions on its use for irrigation. According to the results, all the stations are in the category of S1C2 and S1C3 and no limit to irrigation. Water of region containing a high percentage of nitrate, one of the most important factor is the high level of ​​cultivation and unnecessary use of nitrate fertilizers. Among the heavy metal, cadmium in only a few cases were exceeded.

In this paper, the ozonation and ozonation with activated carbon methods to remove cefixime medicinal material from aquatic environments have been studied. The results showed that ozonation has had a positive impact on removal of cefixime from aquatic solution, so that the concentration of medicinal contaminant has decreased from 55 ppm to 6 ppm in 30 minutes. Moreover, the COD parameter was reduced by 51%. According to the obtained values, the effect of activated carbon on a certain concentration of medicinal contaminant has been confirmed. Also, the effect of different operational parameters such as concentration of contaminant, concentration of activated carbon, concentration of inlet ozone, reaction time and pH on the process of ozonation with activated carbon was investigated. The maximum removal efficiency of cefixime from aquatic environments was obtained as 96%. This number was obtained at the pH level of aquatic solution which was about 4

In this paper, ozonation method is used to remove carbendazim from aquatic environment. In this method, the produced ozone gas passes through an injector and then is converted into little bubbles and finally is injected into the synthetic wastewater. Spectrophotometer was used to measure carbendazim concentration. The complete factorial method was used to design the experiment. This design is considered to be repeated for two times for time parameters at five different levels of 5, 10, 15, 30 and 45 per minute, pH levels of 5, 6.73 and 9, and initial concentration of carbendazim levels of 2, 6, and 10 mg/l. The results showed that the maximum removal efficiency of carbendazim was 91% for a period of 15 minutes, pH level of 9 and concentration of 10 ppm and the most effective parameters on carbendazim removal efficiency have been initial carbendazim concentration, initial wastewater pH and ozonation time, respectively.

In this paper, the risk of chemicals existing in one of the automobile tire manufacturing industries has been investigated using a semi-quantitative risk assessment method. This research is based on the pattern which is provided by the Singapore professional health department to assess the risk of chemicals in the factory. The results showed that the tested employees in this study are in contact with 28 different chemicals. Among these chemicals, benzene, vinyl chloride and solvent 410 are at very high risk. Vinyl chloride is used in units of banbury, extruder and semenzeni. Benzene is used in extruder unit and solvent 410 is used in extruder, baking and inspection units. Due to the high-level risk of these chemicals, safety measures should be taken into account in targeted factory as soon as possible to safeguard employees.

Determining the exact level of environmental knowledge of engineering courses is important because of their importance in their job prospects and engagement in environmental activities. In this research, the environmental knowledge of engineering students at Sahand University of Technology of Tabriz has been evaluated. In this regard, statistical survey of 360 university students was conducted using stratified sampling method from 3 university engineering faculties in undergraduate, senior and Ph.D. sections by gender. The evaluation was performed using a standard questionnaire and the obtained data was processed using Excel software. The results showed that 44.5% of the students lacked an appropriate level of environmental knowledge. Meanwhile, only 10 percent of the students reported that the university's performance was good about raising the student's environmental knowledge. 32.4% of the students acknowledged that the promotion of environmental knowledge of the students was of great importance. According to the results, 17% of students are willing to take an environmental education course. The results showed that despite of improving the students' educational level, the level of environmental knowledge of students does not change much, which could be a warning to university officials in order to take steps to improve the University's performance in raising of the students' environmental knowledge, which today is one of the fundamental issues discussed in the industrial era.

The removal of heavy metals from industrial wastewaters is an important issue due to their high toxicity. In this research, the conditions of simultaneous removal of heavy metals from industrial wastewater (Khark Island petrochemical wastewater as a case study) have been investigated. By testing of some samples, the quality of wastewater was analyzed. The results showed a high amount of organic matters in wastewater which even after the treatment processes are not removed completely. Then, to reduce the heavy metals in the wastewater, a method based on adsorption using activated carbon was investigated. The activated carbon was made from walnut shell. After the synthesis of activated carbon and evaluation of its adsorption characteristics, some tests were carried out of using samples of petrochemical wastewater. The considered absorption parameters were temperature, pH, the amount of absorbent and the adsorption time. The results showed that pH = 6 has the best performance on heavy metals removal. Based on the results, the equilibrium time for lead, copper, chrome was obtained 60 minutes while this value for nickel was equal to 300 minutes. The results also showed that the increase in temperature had an increase in the adsorption efficiency. Finally, the result showed that the activated carbon concentration equal 18g/L wastewater caused the best in heavy metals removal.

The main objective of this research is to study the effect of wind blowing and type of fuels on the production of CO2, NOx and THC in gas flares combustion and qualitative study the effect of these changes on the flame structure and color. For this purpose, a pilot scale gas flare was used for carrying out the experiments and fed by different combination of natural gas, propan and butane. The results of the experiments showed that both wind and the fuel compositions are effective. By reducing the molecular weight of the gas fuel, the production of NOx, CO2 and THC reduced. Also, the rate of the productuions reduced with the increasing speed of the air flow. Of course, the intensity of the effect on the CO2 Changse was more than of NOx.

Recently, the use of hybrid techniques is taken into consideration in wastewater treatment to achieve a high efficiency and effective removal of contaminants especially for resistant contaminants. In this research, the process of a combination of chemical oxidation by ozone and biological oxidation by aerobic attached growth bioreactor in the different modes for treating of wastewater were studied. At first, the performance of aerobic biological reactor was alone studied. Synthetic wastewater (sodium acetate as carbon source and ammonium chloride as a source of nitrogen) with the initial COD of 300 mg/L and the ratio of carbon to nitrogen of 10 was used. The results showed that there is a complete nitrification in bioreactor and COD removal efficiency is 89%. When using ozone oxidation before biotreatment, it was seen that the efficiency of COD removal increased to 94.0% and TSS was achieved to 75 mg/L in output. In the next step, the ozonation was used after biotreatment and it was observed that COD removal efficiency increased to 97.0% and the amount of TSS also decreased to 35 mg/L in output. In the final step, ozonation was used simultaneously before and after biotreatment as pretreatment as well as final treatment. In this mode, the results showed that the efficiency of COD removal in the output of the system increased to 98.3% and the value of TSS was declined to 20 mg/L.

The aim of this study was to investigate the effect of diluents in the NOx emissions and qualitative study of the effect of these changes on the gas burner flame. For this purpose, the effect of dilution was investigated on the combustion process in a laboratory scale gas burner by using various fuels, including natural gas, butane and propane. The nitrogen gas was used for dilution. The results showed that dilution of the fuel significantly reduced the amount of NOx production and this amount of reduction was 30 to 57 percent and depends on the type of fuel and the dilution. On the basis of the results and experimental analysis, the type of the fuel and the amount of dilution are identified as effective parameters on NOx emissions but the impact of fuel type is higher.

Air pollution modeling is an essential tool for air pollution studies. Also, considering that observations are often sparse, models can be used to make inferences on concentrations where there is no information. Due to switching fuel of Tabriz thermal power station from natural gas to mazut in the winters and increasing amount of pollutants emission, also considerable decrease in temperature, pollutants are not distributed well at the region around the emission sources which leads to increasing of pollutants concentration. The current study aimed to consideration of pollutants (NOx and SO2) concentration in areas adjacent to Tabriz power station during winter and comparison of concentration with clean air standards of Environmental Organization of Iran as well as National Ambient Air Quality Standards (NAAQS). Therefore, this study used the ISCST3 (Industrial Source Complex-Short Term) model to simulate pollutant distributions on 3 months period in order to assess the ground level concentration of pollutant in the study area. The results show that SO2 concentration on 24 hours period is more than air pollution standards but NOx concentration is lower than National and International air pollution standards.

Volatile organic compounds (VOC) are the main class of air contaminants that have harmful effects on human, plants and animals. So, it is necessary to prevent VOC’s emission to environment. In this study feasibility of dissolved air floatation for removing VOCs (Toluene as a Case) was evaluated. Air stripping method was used. Also, a pilot plant was constructed. For generation of bubble the technique of dissolved air flotation utilized. In addition the effect of saturator pressure, flow rate of imported saturated water, the proportion of wastewater flow rate to the saturated water was studied.Maximum removal of toluene was 52% that was obtained at p=2 bar, saturated flow rate=0.4 lit/min and the proportion of flow rates=2. Binary and ternary interaction of main parameters analyzed with Minitab 14 software which indicated that proportional of flow rates, saturated water flow rate and saturator’s pressure alternatively had the highest impact on elimination. In this study, air stripping was used for removing organic compounds from effluents.

Carbon dioxide as one of the important combustion product of various industrial units is a greenhouse gas which has a significant influence on global warming. In recent years, porous inorganic membranes have extended for carbon dioxide separation from flue gas. In this study, the microporous silica membrane with nanometer size pores was prepared by template assisted sol-gel method using methyltriethoxysilane (MTES) as organic template and influence of the surface modification on the membrane separation performance was investigated. To fabricate the membrane, α-alumina macroporous support was prepared by gel casting method using ceramic alumina powder. The uniform γ-alumina mesoporous layers were selected as surface modification strategy, in which the supports were coated by alkoxide boehmite sol via dip coating method. The morphology of membrane layer was investigated by scanning electron microscope, indicating the formation of a uniform layer from γ-Al2O3 and silica. Permeance characteristics of the synthesized membrane were studied in two parts: permeance of pure gases such as carbon dioxide, nitrogen and hydrogen, and separation of 50/50 ratio (vol%) mixture of carbon dioxide and nitrogen. For the modified templated silica membrane, the CO2/N2 ideal selectivity and pure CO2 permeance were achieved 11 and 4×10-8 mol/m2.s.Pa, respectively. The real selectivity of CO2 in the mixture (CO2 and N2) with 50/50 ratio (vol%) was achieved 5.3.

In the past decade, the municipal and industrial solid waste production has become one of the main environmental challenges. Municipal Solid Waste (MSW) generation continues to grow both in per capita and overall terms [1]. Overall, the liquid generated due to the agglomeration, pressured and chemically interacted intosolid waste is called leachate [2]. The characteristics of landfill leachates depend on a number of complex factors, including the nature of the deposited wastes, soil characteristics, the “age” of the landfill, weather conditions such as rainfall patterns, the design and the means of operation of the landfill [3-5]. By considering the leachate characteristics, operation and capital costs as well as regulations, various site-specific treatment techniques can be used to treat these hazardous wastewaters (e.g. coagulation/ flocculation, biological, oxidation, membrane, leachate recirculation through the landfill, grassland spray irrigation, etc.) [6]. Therefore, treatment of hazardous liquidwastes by oxidation processes such as ozonation (due to high oxidative power of the ozone) has gained popularity. It has been shown that ozone is capable of destroying recalcitrant compounds in effluents and bringing about alterations to biodegradability. Mainly, Biodegradability of high molecular weight of organic compound is low, so that they cannot be removed simply through biological treatment [7]. In this study, the leachate was sampled from landfill in Anakhatoon region situated in Tabriz city. This landfill mainly is used for the disposal of municipal solid wastes. Samples were transported to the laboratory for Analyzing. Before any processing, samples were exposed to ambient temperature for 3 to 5 days to settle mud and coarse particles. The COD and BOD5 analyses were performed according to the standard methodology [8]. Absorbance of samples at wavelength of 254 nm was determined by means of UV–visible spectrophotometry (Spectroquant Pharo 300 (Merck, Germany)). Also, the absorbance value at 455 nm was measured by Spectroquant Pharo 300 using visible spectrophotometry. Some of the characteristics of the two samples of landfill leachate used in this work are presented in Table 1. 3.1. COD removal, color removal and aromatic compounds removal The reduction of COD content, the percentage of color removal and the percentage of aromatic compounds removal is shown as a function of reaction time in Fig. 2. It is clear that the maximum removal for leachates with COD0 =22000 mg/L and COD0 =1900 mg/L obtained 57.99% and 59.27%, respectively. On the other hand, in this work, ozonation effect on color change was determined by measuring absorption of samples at wavelength of 455 nm as an index. It is clear that a major part of decolonization occurred during ozonation [9]. During the current study, the initial dark brown color of the leachate sample, which can be attributed to the presence of humicsubstances, became light yellow as the oxidation reaction by ozone was preceded. Discoloration of landfill leachates is evidence of the transformation of recalcitrant organic matter by ozone [10]. Also, the absorbance of samples at wavelength of 254 nm can be directly related to the presence of aromatic and unsaturated structures of organicsubstances and it is considered as an additional quality parameter of most wastewaters. Similarly to the decolorization reactions, the reduction of UV absorbance took place by a high rate during the initial stages of ozone treatment. In this paper, by using a new reactor system contained a centrifuge pump and a venture tube, the capability of ozonation in treatment of the leachate generated in the landfill was indicated. The influences of initial COD value was studied on the COD, color and aromatic compounds removal. For leachates with COD0 =22000 mg/L and COD0 =1900 mg/L, 57.99% and 59.27% percent of COD removal, 85.15% and 94.94% percent of color removal and 39.65% and 82.71% percent of aromatic compounds removal was obtained, respectively. The changes of pH during the ozonation process were minimal because of buffering effect of bicarbonates present in the system.

Recently increasing energy consumption and subsequent increase of emissions from fossil fuel combustion have caused major enviromental problems in the world. As reported in literature, about three quarters of carbon dioxide increase is due to fossil fuel combustion, therefore avoiding greenhouse gases emissions especially carbon dioxide, has become an important concern in industries. In recent years, membrane processes have shown high potential to be replaced to conventional CO2 separation processes from gas streams. No phase change, low energy consumption, small scale of membrane systems, no waste streams, easy operation, compatibility with environment and low capital and operating costs propel researchers to apply this novel technology. In this study, a review of conventional membranes in separating carbon dioxide from the gas streams is done and the performance of membranes are compared using the trade-off curves. It is shown that silica membranes have higher performance compared to the other conventional membranes.

Oil and gas processing plants are one of the most air pollutant industries. In this paper, gaseous air pollutants emission factors were estimated for pollutant sources in an Iranian Natural Gas Liquids (NGL) plant using fuel analysis method and published emission factors. The results showed that the main pollutant sources in this unit are gas flare, gas turbines, pit and boiler. Total Hydro Carbons (THC) and CH4 emissions from gas flares and NO2 emission from gas turbine are higher than any other pollutant sources. Activity based emission factors were determined as 513.3, 2731.0, 0, 1805.3 and 225.6 g/1000kg LPG for NO2, CO, SO2, THC and CH4 respectively on the basis of LPG production in the unit. Because of possible gas leakages from the units, CH4 emission factor have larger margin of error. Calculated emission factors can be used for emission estimation of air pollutant in other similar NGL processing units.

Emission factors technique is one of the simple and low cost methods for estimating pollution from air pollutant sources. However, emission factors of gas flare may have high uncertainty because in flares, especially under emergency conditions, flow rate of flaring gases as well as combustion efficiency are unknown. The aim of this paper is to evaluate SO2, NOx and CO emission factors in gas flares. For this purpose, emission factors were estimated using back calculation method based on modeling and pollutant emission measurement in ambient air in a selected flare in an Iranian oil and gas plant. SO2, NOx and CO average emission factors for selected flare are determined to be 0.037, 0.0168 and 1.07 MMBtu/lb, respectively, with uncertainty of 34.3, 36.3 and 27.5%, respectively. Comparison of calculated emission factors with United States Environmental Protection Agency (EPA) and Regional Association of Oil and Natural Gas Companies in Latin America and the Caribbean (ARPEL) emission factors showed that both emission factors have high uncertainty, especially for NOx and CO emission estimation. Therefore, it is necessary to study details of the influence of ambient conditions on combustion efficiency of flares as well as experimental simulation of actual flare to obtain more representative emission factors of flares.