Sharif Digital Repository

The aim of this research is the study of hexyltriphenylphosphonium bromide (HTPB) ionic liquid as a bifunctional promoter (solvent and catalyst) in the presence of cerium(IV) ammonium nitrate as a single electron oxidant for the Michael reaction at room temperature and solvent-free conditions. A novel, one-pot and environmentally benign the process to achieve the chemoselective of 2-(3-oxo-1,3-diarylpropyl)malononitrile derivatives instead of 2-(1,3-diarylallylidene)malononitriles using a three-component reaction involving acetophenone derivatives, various aromatic aldehydes and malononitrile was developed. This protocol is simple and provides biologically interesting products in good... 

This review paper is devoted to the intensification of processes for nitrate removal. First, the developments of microfluidic sensors for nitrate detection and analysis have addressed. Second, the process variables of photocatalytic nitrate removal have been categorized according to their relationship with activity, selectivity and stability of the catalyst. The objective of this classification is to generate guidelines toward the photocatalytic process optimization. Third, because of the fact that a single method for nitrate removal faces some challenges, hybrid methods have been presented, and the best choice for nitrate removal can be referred to as photocatalytic – reverse osmosis... 

The aim of this research is the study of hexyltriphenylphosphonium bromide (HTPB) ionic liquid as a bifunctional promoter (solvent and catalyst) in the presence of cerium(IV) ammonium nitrate as a single electron oxidant for the Michael reaction at room temperature and solvent-free conditions. A novel, one-pot and environmentally benign the process to achieve the chemoselective of 2-(3-oxo-1,3-diarylpropyl)malononitrile derivatives instead of 2-(1,3-diarylallylidene)malononitriles using a three-component reaction involving acetophenone derivatives, various aromatic aldehydes and malononitrile was developed. This protocol is simple and provides biologically interesting products in good... 

Carbonaceous radioactive waste is produced by adsorption of effluent gases of UF6 production line, on a bed of charcoal. Current research was aimed at developing a process for recovery of uranium from this waste in a laboratory and at pilot scale. As a first step, leaching of uranium from carbonaceous radioactive waste was undertaken by successive steps using Al(NO3)3 and nitric acid, the former used to eliminate corrosivity of the F− ions. The stoichiometry of reaction between F− and Al3+ ions form complexes ranging from AlF2+, AlF2+ to AlF3 depending upon their molar ratio. The results showed that the increase of NO3−/U ratio increased the uranium leaching efficiency. Presence of some... 

A novel catalyst of sulfidated iron-nickel supported on biochar (S-FeNi@BC) was synthesized to activate persulfate (PS) for the removal of trichloroethylene (TCE). A number of techniques including XRD, SEM, TEM, FTIR, BET and EDS were employed to characterize S-FeNi@BC. The influence of sulfur to iron ratio (S/F) on TCE removal was investigated by batch experiments and a higher TCE removal (98.4%) was achieved at 0.22/1 ratio of S/F in the PS/S-FeNi@BC oxidation system. A dominant role in iron species conversion was noticed by the addition of sulfur in FeNi@BC system. Significant enhancement in recycling of the dissolved and surface Fe(II) was confirmed which contributed to the generation of... 

Superhydrophobic surfaces demonstrate significant characteristics which make them suitable for a wide variety of applications. In this study, we propose a facile, one-step, and cost-effective anodizing scheme using aluminum nitrate/stearic acid mixture solution to create a superhydrophobic surface on an aluminum mesh. The surface outperforms the surface anodized by the widely used oxalic acid solution in terms of superhydrophobicity and water-surface friction behavior. The proposed surface reduced the friction by 11% on average respective to the surface prepared by oxalic acid. The durability of the introduced superhydrophobic surface has also been investigated. The proposed surface retained... 

Herein, we deposited CuInSe2(CISe) thin films by using aqueous spray deposition method and post selenization process. The effect of different indium precursor salts including indium chloride, indium nitrate and indium acetate on the structural, morphological, optical and electrical properties of sprayed CISe layers has been studied by using x-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM-EDS), optical transmission (UV–Vis), Mott-Schottky analysis, I–V dark measurements. Although all the deposited thin films show a chalcopyrite tetragonal ordering structure of CISe, the crystallinity, morphology, and electrical characteristics are strongly influenced by the type of... 

The present study aimed at investigating the biological treatment of nitrogen and phosphorus from the saline wastewater in various systems. In the end, moving bed biofilm reactor and anaerobic/anoxic/aerobic (AOA) were chosen as the best systems. In the present study, the investigations were carried out in two 24-h and 12-h retention times for three nitrogen concentrations, 200 mg/l, 300 mg/l, and 400 mg/l, two phosphorus concentrations, 14 mg/l and 20 mg/l, three Chemical oxygen demand (COD) concentrations, 800 mg/l, 1000 mg/l, and 1200 mg/l, and four salt concentrations, 10 g/l, 12 g/l, 17 g/l, and 20 g/l. The obtained results indicated that the COD removal percentage was high in a range... 

With over 8 million inhabitants and 4 million motor vehicles on the streets, Tehran is one of the most crowded and polluted cities in the Middle East. Frequent exceedances of national daily PM2.5 limit have been reported in this city during the last decade, yet, the chemical composition and sources of fine particles are poorly determined. In the present study, 24-hour PM2.5 samples were collected at two urban sites during two separate campaigns, a one-year period from 2014 to 2015 and another three-month period at the beginning of 2017. Concentrations of organic carbon (OC), elemental carbon (EC), inorganic ions, trace metals and specific organic molecular markers were measured by chemical... 

The g-C3N4/Fe2O3 nanocomposite was produced by the solution combustion synthesis (SCS) of iron-nitrate/g-C3N4 mixtures of varying concentration ratios and using urea as a fuel. The following methods did characterization of the products: X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller investigation (BET), ultraviolet–visible light analysis (UV–vis) and photoluminescence measurement (PL). Effect of iron nitrate on stability and photocurrent density under simulated visible-light irradiation was determined. The... 

The present study shows the approach developed and employed to wastewater treatment utilizing the vermifiltration technique in a region with a population of approx. 280 people. The domestic sewage from the residential area accumulated in the septic tank was fed into the system designed based on the combination of the sand filter and the vermifilter with the optimum loading rate of 2m2 per day for 45 days. The pH, electrical conductivity, chemical oxygen demand, turbidity and nitrate concentration of wastewater were measured before and after vermitreatment for the mentioned period. The results demonstrated that the unique combination of the vermifiltration system with the sand filter was able... 

Many communities in arid and semi-Arid areas rely on groundwater for drinking water. However, anthropogenic activities such as the use of fertilizers and human waste disposal impose the risk of nitrate pollution to the aquifers. With over 8.5 million population, Tehran, the capital of Iran, has experienced rapid population growth during the past decades while the majority of the city did not have a sewerage network and the main way of wastewater disposal was individual cesspits inside houses. The long-Term discharge of raw wastewater in cesspits has increased nitrate concentration in the Tehran aquifer which serves as a source of one-Third of drinking water for the city. Although the... 

Urea is a major source of nitrogen pollution in domestic sewage and its denitrification is difficult since it is very likely to be converted into ammonia or nitrate instead of expected N2. Herein, we propose an exhaustive denitrification method for urea via the oxidation of amine/ammonia-N with chlorine oxide radical, which induced from a bi-functional RuO2//WO3 anode, and the highly selective reduction of nitrate-N on cathode in photoelectrochemical cell (PEC). Under illumination, the WO3 photoanode side promotes the quantities hydroxyl and reactive chlorine radical, and these radicals are immediately combined to stronger chlorine oxide radical by RuO2 side, which obviously enhances the... 

This review paper is devoted to the intensification of processes for nitrate removal. First, the developments of microfluidic sensors for nitrate detection and analysis have addressed. Second, the process variables of photocatalytic nitrate removal have been categorized according to their relationship with activity, selectivity and stability of the catalyst. The objective of this classification is to generate guidelines toward the photocatalytic process optimization. Third, because of the fact that a single method for nitrate removal faces some challenges, hybrid methods have been presented, and the best choice for nitrate removal can be referred to as photocatalytic – reverse osmosis... 

The purpose of this study is to investigate production of high quality ammonium uranyl carbonate (AUC) from “uranyl nitrate + ammonium bicarbonate”, or “uranyl nitrate + sodium carbonate” precursor solutions, by controlled injection of ammonium carbonate solution which could be applicable in material testing reactor (MTR) fuel production plant for recycling of rejected uranium oxide powder. The experimental observations revealed: at pHs higher than 6, precipitation proceeds with formation of no intermediate, thus ensuing a better morphology and size distribution of the AUC products. The results of scanning electron microscopy, X-ray diffraction, particle size analysis, and uranium content... 

One of the efficient solar energy harvesting technics is the parabolic trough concentrated solar power plant. However, if the concentrated solar power plant were not equipped with a storage system, the power plant capacity factor would be deficient. Latent thermal energy storage system using phase change material (PCM) is a high energy density storage system to provide durable energy with a constant temperature. In this study, first, a dynamic analysis is performed implementing TRNSYS software on the parabolic trough concentrated solar power plant located in Shiraz, Iran. Consequently, this system is assisted by the latent thermal energy storage system to improve its performance and capacity... 

In this study, four types of mixed matrix membranes were fabricated using polysulfone (as the base polymer) and different contents of graphene oxide (GO) nanosheets (as modifier) through wet phase inversion method. Based on the amounts of GO (0, 0.5, 1, and 2 wt%), the synthesized membranes named as M1, M2, M3, and M4, respectively. The membranes characteristics were evaluated using FE-SEM, FT-IR, and water contact angle measurements. In addition, the performance of the prepared membranes was investigated in terms of basic parameters: filtrate water flux, nitrate removal efficiency, and antifouling properties. Results showed significant improvements of the characteristics of modified... 

The main goal of this research is to use the biomass productivity, carbohydrate content, and carbohydrate productivity as useful responses for optimization of macronutrients concentrations (K2HPO4, NaHCO3, and NaNO3) in cultivation of Spirulina microalgae as a feedstock for bioethanol production. In this study, individual and synergistic effects of medium components on the mentioned responses were investigated. The culture medium was optimized using central composite design for achieving the maximize biomass productivity (165 mg L−1 day−1 at K2HPO4: 438 mg L−1, NaHCO3: 15.92 g L−1, and NaNO3: 0.5 g L−1), carbohydrate content (42.0% of dry mass at K2HPO4: 192 mg L−1, NaHCO3: 5.71 g L−1, and... 

In this study, solvent extraction method has been utilized for separation of molybdenum and vanadium from nitrate solution by utilizing coupling of acid and solvating extractants (D2EHPA and TBP extractants). The outcomes demonstrated that synergistic solvent extraction improves stability of formatted complexes for transfer to the organic phase. The main parameters such as pH value, concentration of extractants, NH4OH concentration as the stripping agent and contact time were optimized at 0.4, 15% (v/v) D2EHPA, 10% (v/v) TBP, 2 M and 30 min, respectively. The maximum separation factor of 24.84 was obtained with a new synergistic mixture of D2EHPA and TBP diluted with kerosene. According to... 

Nutrient pollution has become a global environmental issue. Innovative biological nutrient removal (BNR) processes are needed to overcome the drawbacks of conventional technologies. This study evaluates the potential of a hybrid 5-stage Bardenpho - moving bed biofilm reactor (MBBR) process for organic carbon and nutrient removal from municipal wastewater at different hydraulic retention time (HRT) and nitrate recycle ratio (R). Response surface methodology (RSM) based on a central composite design (CCD) of thirteen experiments was applied to optimize the nitrogen and phosphorus conversion of the treatment system. High removal efficiencies of about 98.20%, 92.54%, 94.70% and 96.50% for total...