amir vahid

Flammable Modern Natural Gas besides being colorless, is also odorless. An activity like adding an odorant to gas means odorization. This operation is done to ensure that the gas can be distinguished. In other words, odorization is done to create an unpleasant smell in the air, so that the natural gas, even in small amounts, can be easily identified. Improving safety and increasing the efficiency of utilization of natural gas is a very important subject due to its wide use as one of the main energy sources in industry and home consumers all around the world. So far, various types of compounds identified as "odorant" are increasingly being produced and formulated to be injected into natural gas. This review article describes different aspects of classical and modern natural gas odorants and their odorization process to endorse the introduction of universal sulfur-free odorants for public gas systems. After studying basic chemistry and the history of these compounds, the most important properties of odorants are presented to help recognize the most proper odorant for a specific application and its synthesis methods.

The purpose of this research is to investigate the factors affecting cocaine use in Tehran.

The research is applied in terms of purpose and descriptive-survey in terms of type and method. Because, in addition to expressing the nature, characteristics and attributes of the current situation, it examines various factors involved in the spread and distribution of narcotics and also describes and explains the problem and its dimensions; And it is based on practical purpose. The statistical population includes 81 anti-narcotics police specialists who work in the fight against narcotics, especially cocaine-type drugs, which is considered as a whole number. The tool of data collection is a questionnaire made by the researcher in the form of 32 questions in 5 economic dimensions; political-security; Sociocultural, Legal-juridical and geographical-environmental is designed. The validity of the questionnaire was confirmed by anti-narcotics experts and its reliability was obtained by Cronbach's alpha of 0.73.

The findings showed that among the identified influencing factors, political-security factors with an average of 3.88 are the most effective in cocaine use in Tehran, and then in order; Agents Legal-judicial factors with an average of 3.64, geographical- environmental factors with an average of 3.50, economic factors with an average of 3.37 have had a greater impact on the increase in cocaine consumption in Tehran. Also, the socio-cultural factor was not included in the ranking because it was not significant.

by controlling the determined economic factors and indicators; political-security; Legally, geographically and environmentally, it is possible to prevent the consumption and smuggling of cocaine in Tehran.

In the present work a multifunctional nanoadsorbent was synthesized via a well-designed stepwise route, led to the grafting of an amine group on the interior and acidic sites on the exterior of bimodal mesoporous silica nanoparticles (UVM-7). First, amine and thiol groups were grafted on the interior and exterior pores of silica through co-condensation and post synthesis treatment, respectively. Then, the oxidation of thiol on UVM-7 caused to create sulfonic acid and the subsequent template extraction was carried out to obtain the NH2/UVM-7/SO3H.  The results of XRD, the nitrogen sorption, SEM, TEM, FT-IR and elemental analysis revealed the presence of both types of functional groups on UVM-7. Then, simultaneous adsorption of anionic and cationic dyes (Methylene Blue [MB] and Direct Red 23 [Dr]) using NH2/UVM-7/SO3H was investigated. UV-Vis spectrophotometry was utilized for the determination of dyes in single and binary solutions. Langmuir and Freundlich models were used for the fitting of obtained experimental adsorption data and the constants of both isotherms were calculated for MB and Dr. Morover, the calculation of thermodynamic parameters revealed that the adsorption of MB and Dr on NH2/UVM-7/SO3H was endothermic and spontaneous.

In this study, re-refining of used insulating oil by mesoporous silicate material (MCM-41) and metallic sodium was investigated. Also, the effect of silicate absorbents which was synthesized and functionalized with aluminum (Al-MCM-41) was studied (18 wt% and 36 wt%). The physical and structural properties of Al-MCM-41 were characterized by FT-IR, BET, XRD, FESEM and the obtained results illustrated a successful synthesis of the mesoporous material. The refined oil was treated by MCM41 adsorbent. After that, total acid number (TAN) of used insulating oil was effectively reduced by metallic sodium. The effect of some parameters such as contact time, temperature and the dosage (sodium and adsorbent to oil ratio) was designed and optimized by response surface method (RSM). The results showed that the acid number incredibly decreased at 150, 60 min and 2% of sodium to oil. The color of the re-refined oil was significantly reduced. The factors such as, time, temperature and dosage was statistically studied by ANOVA. The adsorption of MCM-41 was also studied by this way. Based on proposed procedure, the modeling was carried out. Treating of oil with MCM-41 after using metallic sodium causes lower color of oil.

Adsorptive desulfurization using mesoporous carbons are of the preeminent methods to meet serious international standards in case of sulfur. In this research, the absorbent CMK-3 containing nickel nanoparticles was synthesized and characterization using XRD, BET, SEM and FT-IR. The results showed that the nanostructure was formed and the despite high nickel loading, structural order is still preserved and specific surface of the synthesized samples is maintained at an acceptable level. Then, in the next step, the capability of synthesized adsorbent was carried out in various conditions, which shows the significant yield of them in both low and high temperature. In addition, the absorption yield of these nano-adsorbents was preserved after several reduction, indicating the high potential of these adsorbents in desulphurization.

Determination of hydrogen sulfide, (H2S) in crude oil is very important due to the environmental impacts, industrial problems and legal international limitation of transportation. In the present work, H2S of crude oil is determined by liquid-liquid extraction followed by potentiometric titration. Three factors including dilution ratio of crude oil with toluene, extraction time of H2S into the caustic phase and API of crude oil was investigated via factorial design. The ANOVA results revealed that the dilution ratio, crude type and extraction time have the highest effect of the recovery of H2S from crude oil. The linear dynamic range of the method was from 1 up to 2000 ppm which can be manipulated for lower or higher concentration by further optimization of the above-mentioned parameters. This method is rapid, reliable, operator-independent which make it a useful technique for the field test of crude oil and overcome extreme uncertainty of H2S measurement.

The effect adsorption of cobalt-phthalocyanine-3,4’,4”,4”’- tetrasulfonicacid tetrasodium salt [Co(tsPc)-4•4Na＋] onto UVM-7/Ag mesoporous material was investigated. In addition, X-ray diffraction (XRD), scanning electron microscopy (SEM), and nitrogen adsorptiondesorption measurement were used to examine the morphology and the microstructure of the obtained composite. Various parameters including solution adsorbent dosage, contact time, initial dye concentration and temperature were systematically studied. Equilibrium data fitted well the Langmuir models; moreover, the fitness suggests that the adsorption be monolayer and physical in nature. Kinetic studies showed that the adsorption process could be better described by the Lagergren pseudosecond- order models. Thermodynamic constant values (ΔG < 0, ΔH< 0 and ΔS< 0) demonstrated that the adsorption reactions of Co(tspc)-4 onto UVM-7/Ag were feasible, spontaneous, and exothermic under the examined conditions.

In this study, bimodal mesoporous silica, i.e. UVM-7, was synthesized and functionalized withsulfonic acid and characterized using XRD, nitrogen physisorption, SEM, TEM and acid/basetitration. The results displayed that bimodal mesopore structure was firmly formed and acidicfunctional groups were grafted on the surface of the UVM-7. The concentration of the acidicfunctional groups was determined via titration by the standard NaOH solution. At the secondstep, the adsorption of methylene blue from aqueous solutions onto UVM-7 and UVM-7/SO3H was investigated. The effect of PH, temperature, dye concentration, salt concentrationand contact time on the adsorption of methylene blue was studied. The adsorption equilibriumisotherms were well fitted to Langmuir rather than Freundlich model. Methylene blueadsorption on UVM-7 increases with increasing the temperature and PH, which indicatesthat the process is endothermic. Maximum adsorption capacity of methylene blue by UVM-7and UVM-7/SO3H were 107.5 mg/g and 129.9 mg/g, respectively. The adsorption kinetics ofmethylene blue for both UVM-7 and UVM-SO3H were pseudo-second order and well fitted toLangmuir model.

H2S is a major toxic compound that could be found in air, water, Fossil fuels and causes some worse effects such as acidic rain and corrosion. In the present work SBA-3 (Santa BarbarA University no. 3) with three different weight percent’s of ZnO, i.e. 5%, 10% and 15% was synthesized via an in situ approach. All synthesized samples were characterized using atomic absorption spectrometry, X-ray diffraction (XRD), nitrogen adsorption and transmission electron microscopy (TEM). The obtained results from XRD and nitrogen adsorption confirmed that all the samples almost retained their ordered structure after incorporation of ZnO nanoparticles within the mesopores of SBA-3. TEM images show that ZnO nanoparticles arranged along the direction of mesopores of SBA-3. Then, adsorption of H2S from a model gas was investigated. A three factor Box–Behnken design with five center points and one response was performed for the evaluation of effect of three process parameters, i.e. ZnO wt%, space velocity and temperature on the adsorption of H2S and a quadratic model (r2 : 0.9185) was developed to navigate the design space. Temperature had the largest and space velocity had the lowest effect on the breakthrough of H2S. The optimum breakthrough time (tbp) was 588 min.

Oscillating chemical reactions are complex systems involving a large number of chemicalspecies such as ionic, radical and molecular intermediates, which exhibit fluctuation in their concentration with time. One of the oscillating chemical reactions is BZ {H2SO4-KBrO3-CH2(COOH)2-Ce(IV)}System. In this work for the first time a new, simple and appropriate method, i.e.conductometry, have applied for the investigation of BZ oscillating system.Furthermore, presence of SiO2 nanoparticles containing NiO apparently affected the intensity and period of BZ system. The effect of varying concentrationof , , and on the conductance of BZ oscillating chemical system at 20 (±0.1)°C was also investigated. The obtained results of this work indicated that rather than potential and color of the BZ system, the conductance of system is also oscillates during the reaction and is also proportional to the reactants concentration as well. The intensity, intensity and period of the oscillation are strongly depending on the concentration of reactants.

In the present study, adsorption of Co(tsPc)-4 using γ-Alumina was investigated. γ-Alumina was prepared by gel combustion method. The XRD pattern revealed that the synthesized γ-Alumina is amorphous and SEM image showed its nanosize scale while BET surface area about 501 m2/g and pore size of 7 nm implies highly porous surface which is a characteristic property of a high-quality adsorbent. In the second step of this study, the effects of adsorbent dosage, initial Co(tspc)-4 concentration and contact time were investigated. Upon the obtained UV-Vis spectra, λmax of 664 nm was used to determine the concentration of Co(tsPc)-4 after adsorption. From the Langmuir isotherm the maximum adsorption capacity of γ-Alumina toward Co(tsPc)-4 was determined (Qm=333.33 mg/g). Although Co(tsPc)-4 adsorption occurred in the first 40 min of contact time, at least 90 min time was needed to attain equilibrium. The kinetics of adsorption can be described by second order rate equation. After that, statistically based experimental design, i.e. as Box–Behnken design (BBD), was used to study the effect of independent variables on the adsorption. Regeneration studies of the adsorbent were carried out and it was found that the adsorbent can be effectively regenerated up to 3 times with no significant deactivation. The obtained results suggest γ-Alumina is high quality adsorbent for the removal of Co(tsPc)-4 from aqueous waste streams in different industries such as painting and oil & gas in MEROX unit.

In this contribution, an effective and soft method for removal of template from nanochannels of mesoporous silica (MCM-41) is proposed. This method is based on chemically-modified solvent extraction which enhanced by means of an auxiliary organic compound, i.e. benzene sulfonamide. Template removal was performed in soft condition, i.e. in the presence of diluted sulfuric acid and at ambient temperature. Presence of benzene sulfonamide extremely improves efficiency of template removal process. The template-extracted mesoporous silica was characterized using powder X-ray diffraction, nitrogen adsorption, transmission electron microscopy, thermogravimetry, elemental analysis and FT-IR spectrometry. Results of XRD, nitrogen adsorption, and TEM displayed that well-ordered hexagonal array of mesopores remained intact after extraction. The obtained results from  thermogravimetry, elemental analysis and FT-IR spectrometry indicate that at least up to 94 wt % of template was removed in short time.

Naphthenic acids and TAN are one of the ever-increasing crucial problems in oil, shale oil and sand oil industry and also environment protection. Furtherer, they increases the corrosion of some parts of a refinery and transport pipelines and also can create nanoemulsions and make complicated the refining process especially in desalters. To prevent these problems it is important to first obtain a basic knowledge about the distribution/structure of Naphthenic acids and their relationship with TAN. This might be useful for troubleshooting of probable problems when the feed of refinery changes. In the present work, two fractions of Soroush-Norowz blend crude oil were analyzed to obtain their naphthenic acids concentration and TAN. At the second step, these two fractions were physically to sub-fractions by 25 °C intervals. After that, their naphthenic acids concentration and TAN was determined to obtain a detailed view about the distribution of naphthenic acids and TAN of each sub-fraction. In addition, the obtained results gave us a view point about the overall molecular structure of naphthenic acids presents in the Soroush-Norowz blend crude oil and can guide us toward better understanding of chemical structure of mentioned crude oil and consequently better designing of oil refinery in order to minimize the corrosion and also upper the performance of some special units such as desalters.

Hydrogen sulfide is one of the most dangerous contaminants in crude oil and natural gas that have to be removed prior to the transfer and refining. In this study, hydrophobic ionic liquid, i.e. 1-ethyl-3-methylimidazolium methylflour, [EMIM] [NTf2], was used as scavenger for the reduction of the H2S. Due to its ionic nature, [EMIM] [NTf2] forms nanoemulsion in crude oil media and hence can dissolve H2S polar molecules within its core. Determination of H2S was carried out using well-known UOP-163 potentiometric titration. The effect of [EMIM] [NTf2] on the H2S concentration was investigated via two methods dynamic and static. Dynamic method performed to check the effect of required dosage for the removal of H2S and also investigate effect of contact time. In the static methods a number of tests were designed with central composite design (CCD) to investigate the effect of three factors, i.e. scavenger dosage, reaction time and temperature, as well as the interaction between them on the concentration of H2S via response surface methodology (RSM). Among these three factors and according to the F value, scavenger dosage and time had the great influence on the response, respectively. In comparison, temperature had very low effect on the response. The resulted model was also statistically significant with non-important LOF index.

On-line solid phase extraction (SPE) based on  nano adsorbent for pre-concentration of inorganic arsenic in water and waste water samples was developed prior to determine by hydride generation atomic absorption spectrometry (HG-AAS). By hydride generation simulation system (HGSS), the  inorganic arsenic in liquid samples changed to hydride form and pass through nano platinum multi wall carbon nanotube (3 wt % Pt, NPt-MWCNT,). The hydride form of arsenic (AsH3), pre-concentrated on NPt-MWCNTs and then completely desorption by electric heater accessory at 200oC for determining. The detection limit (LOD) and linear range of perposed method were obtained 0.4 ng L-1 and 6 –410 ng L-1 respectively(R2 = 0.9988). The relative standard deviations (%RSD) at 100 ng L-1 of analyte were found less than 5%. The capacity and efficiency  of nano adsorbent were 75 mg g-1 and 96% at  argon flow rate less than 100 ml min-1. The developed method was applied successfully to determination of ultra trace of inorganic arsenic in environmental samples by HG-AAS.

Silicate mesoporous materials are of the main interesting adsorbents for decreasing of hydrogen sulfide (H2S) from crude oil. In this work zinc impregnated highly ordered MCM-41 was synthesized via post-synthesis functionalization and was used as adsorbent for removal of H2S from crude oil. Also the variation of solvents was mainly adjusted. In  order  to  determine  the  ideal  solvent  for  the  synthesis  of  zinc incorporated MCM-41,  a  few solvents (water, ethanol and THF) has been tried in these experiments. The experiments showed that THF is a better solvent to get better materials.

Synthesis and application of Mesoporous silicate nanoparticles is important area of research in many fields such as drug delivery, medicine, catalysis and optic. The method of synthesis strongly affects the properties of product. In this work, mesoporous silica nanoparticles were synthesized synthesized by means of a hydrogel. The obtained product was characterized by X-ray diffraction, scanning electron microscopy and nitrogen physisorption. The results show that highly ordered mesoporous silica nanoparticles were synthesized by means of a hydrogel.

Sorption of drugs in nano-scale materials such as single-wall carbon nanotubes is a very interesting research in nanomedicine. Nitroglycerin is one of drugs that can be used medically as a vasodilator to treat heart conditions. It is one of the oldest and most useful drugs for treating heart disease by shortening or even preventing attacks of angina pectoris. Nitroglycerin can be used to help destroy prostate cancer as well as being used as a heart medicine. Therefore, the study of capability of delivery of nitroglycerin as a drug may be useful in nano-sacle medicine. We apply Monte Carlo simulations to predict the sorptivity of single-wall carbon nanotubes for nitroglycerin at room temperature and varying pressure. The isotherm diagrams for nitroglycerin sorption report to find mechanism of this fluid sorption in single-wall carbon nanotubes. The sorption isotherms show that nitroglycerin can diffuse inside the single-wall carbon nanotubes while their diameter is larger than 10 Å. Also, these results can be verified with energy sorption plots. The density field and the distribution energy diagram were prepared to verify the sorption isotherms of nitroglycerin inside single-wall carbon nanotubes.

In the present work MCM-41 material was synthesized by a rapid method. The calcined material was characterized using XRD, scanning electron microscopy and nitrogen physisorption. The XRD pattern of calcined sample shows five well-defined peaks that indicates highly ordered MCM-41 material was synthesized. The SEM image reveals that the sample particles are in nanometer range. The isotherm of Nitrogen demonstrates a nearly reversible behavior which implies highly ordered MCM-41 material was synthesized by this method. The BET specific surface area of the sample is about 910 m3g-1. This method is also rapid and simple and results in high quality MCM-41 material.