نشریه شیمی کاربردی روز
پیاپی 56 (پاییز 1399)

In this research work, core- shell ferrite-gold nanoparticles were synthesized by biosynthesis in two steps. In the first step, iron oxide nanoparticles were synthesized by biosynthesis using Mentha aquatic plant extract. The gold shell was then synthesized using gold salt as the precursor on the iron nanoparticles. Synthetic nanoparticles were identified using scanning electron microscopy, visible-ultraviolet spectroscopy, elemental analysis and dynamic light scattering. The presence of the absorbance peak at the wavelength of 529 nm and also the presence of gold, iron and oxygen elements of the elemental analysis confirms purity of the synthesized nanoparticles. The size of the synthetic nanoparticles was determined about 30 nm using X-ray diffraction. Result shows after loading of drug at surface nanoparticle the size of nanoparticles increased from 20 nm to 120 nm that confirm loading process of anticancer drug. In addition, DLS data confirm the stability of system for 20 days. Subsequently, the synthetic nanoparticles were used as carriers for 6-mercaptopurine, and results confirm their ability to load the drug high. IC50 = 4.1 μg / ml was determined for the drug transported by nanoparticles using MCF7 cell line. On the other hand, the toxicity of this drug on the nanoparticles was investigated.

Herein, we study the adsorption and photodegradation of Rhodamin B (RhB) dye on surfaces of CdSe and CdS nanoparticles. First, the nanoparticles were synthesized and characterized. Then the photocatalytic degradation was carried out in a glass photoreactor equipped with a Tungsten lamp. The results showed that the degradation kinetics obeys the Langmuir–Hinshelwood model. Therefore, the values of adsorption equilibrium-constants and the kinetics rate-constants were calculated. The results show that the photocatalytic degradation of RhB under visible light irradiation using CdSe nanoparticles has more efficiency than using CdS nanoparticles. To obtain the adsorption properties, the (0001) facet of CdSe and CdS nanoparticles were modeled as Cd19Se27H16 and Cd19S27H16 clusters, respectively. Then, the adsorption properties were studied using density functional theory methods and the values of adsorption energy were calculated. The calculations show that the adsorption energy of RhB on CdSe surface is larger than the adsorption energy of RhB on CdS surface. The results show that RhB prefers to be adsorbed molecularly (non-dissociative) on the CdSe and CdS surfaces.

In this study, hollow fiber liquid phase microextraction coupled with high performance liquid chromatography is used for determination of rivastigmine and donepezil in wastewater, serum and human urine samples. The method is based upon the utilization of liquid membranes, and, in addition to reduce the consumption of the organic solvents it provides a suitable sample clean-up. According to the method, the target analytes are extracted from an aqueous sample solution into a liquid membrane, and then they are selectively back-extracted into an aqueous acceptor solution. The method was coupled with high performance liquid chromatography and the factors influencing the extraction efficiency were thoroughly examined and optimized. Under the optimal conditions, the method provides a good linearity (in the range of 2–1000 ng mL−1 (R2 > 0.995)). The method provides low limits of detection (in the ranges of 0.5-0.7 ng mL−1) and the enrichment factors are in the range of 150-222.

Two or more materials are combination for the composites synthesis that exhibit different physical and chemical properties than the primitive materials. Today, the use of nanocomposites as adsorbents for the treatment of dusts of dye-producing factories, due to their physical and chemical properties, is one of the fields of interest for researchers. In this study, the kinetics and thermodynamics of the green malachite dye were investigated by two nanocomposite adsorbents including carboxylated multi-wall carbon nanotube, cellulose, and magnesium nano-oxide particles. For this purpose, the first-order kinetic model, four types of second-order kinetic models (type I, II, III, and IV) and the Elovich kinetic model were investigated. Also, Gibbs free energy changes, enthalpy and entropy of the adsorption process were investigated. A kinetic study showed that the process performed with the second-order pseudo-second kinetic model (type II) was better. Also, thermodynamic functions, such as ΔG°, ΔH°, and ΔS° were calculated and it reveals that the adsorption MG dye on both surfaces was spontaneous and endothermic in nature.

In this research, a chitosan and ferrocyanide modified carbon paste electrode has been applied for indirect voltammetric determination of Zn2+ ion. In order to prepare this electrode, first, the chitosan modified carbon paste electrode (Ch/CPE) was fabricated via mixing the certain ratio of graphite powder, paraffin oil and chitosan. Then, ferrocyanide was accumulated on Ch/CPE via electrostatic attraction and as open circuit. The decrease of anodic peak current of cyclic voltammograms of ferrocyanide adsorbed on the chitosan and ferrocyanide modified carbon paste electrode (Fe/Ch/CPE) in Zn2+ ion presence was used for indirect determination of this ion. The effect of various factors on the Fe/Ch/CPE response to Zn2+ ion such as chitosan percentage in carbon paste, ferrocyanide accumulation time on the electrode surface, ferrocyanide concentration and pH solution was studied and optimized. The studies showed that the Fe/Ch/CPE response to Zn2+ ion is linear in two concentration ranges, 0.0019-0.0122 mM and 0.0122-20.00 mM respectively, and the detection limit of method is 5.02 × 10-7 M based on three times the standard deviation (3σ). Also, this method was successfully applied for Zn2+ ion determination in drug real sample.

Antioxidants are molecules that can slow down or prevent the oxidation of other molecules. The role and beneficial effects of antioxidants against many human diseases and foodborne illnesses due to oxidative corruption have attracted much attention in recent years. In this study, synthesis of homo and copolymer of aniline/pyrrole was performed on 2B pencil composite graphite in acetic acid medium containing para toluene sulfonic acid (PTSA) as supporting electrolyte by cyclic voltammetry method and their ability to remove free radical 2,2. -diphenyl-1-picryl hydrazyl (DPPH) have been compared and evaluated. The results indicated that the electrosynthesized polyaniline was more capable of DPPH radical scavenging, which could be due to electrosynthesis of the oxidation state (configuration) of the polyaniline conductive form (Emeraldine Salt (ES)), which was able to remove a greater percentage of DPPH radicals. Also, using electrochemical impedance spectroscopy (EIS), it was found that increasing the aniline ring in the polymer chain decreased the resistance of the charge transfer, thus increasing the reductive property. The structural and morphological of electrosynthesized homo and copolymer have been confirmed by SEM and FTIR.

Metal-organic frameworks have attracted considerable attention because of their unique properties and potential applications in diverse fields. In this research, an efficient and simple method has been reported for the preparation of chromeno[2,3-b]pyridine derivatives through the multi-component reactions of salicylaldehydes, thiols and malononitrile in the presence of NiCo2O4@Ni(BDC) nanocatalyst. In this approache, the products were obtained in short reaction times and excellent yields. Moreover, the synthesized compounds were characterized by IR, 1HNMR and 13CNMR spectroscopy analysis. Also, the catalyst was fully characterized by spectroscopic techniques including field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), fourier transform infrared spectrophotometry (FT-IR), X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and thermogravimetric analysis (TGA).

Use of environmentally friendly hydrogen (H2) as a clean fuel in massive scale requires safe and efficient storage and generation systems. Sodium borohydride (NaBH4) hydrolysis is one of suitable methods for Hydrogen production. However, requirement to expnsive noble metals catalysts limits its commercial usage. In this research, for development of cheap non-noble metal catalysts with high activity and stability, cupper- iron nano catalysts (Cu-Fe) with different mole ratios of (1:1), (3:1) and (1:3) were synthesized and their performane are compared with each other and with pure Cu. According to obtained results, Cu-Fe catalyst with 1:1 mole ratio has the largest specific surface area (170.4 m2/g) in comparision with other sysnthesized catalysts and pure Cu. Hydrogen generation over this catalyst is five times more than produced hydrogen over pure Cu. Then, effect of some stablizers such as Polyvinylpyrrolidone (PVP), tetradecyltrimethylammo- nium bromide (TTAB), sodium dodecyl benzene sulphonate (SDBS) and Triton X-100 on Cu:Fe (1:1) performanec are investigated. It was shown that produced hydrogen over Cu:Fe (1:1) stablized Triton-X-100 catalyst is 35% higher than Cu:Fe (1:1) catalyst without stabilizer. Also, the stability of this catalyst is significat and it maintains 70% of its original activity after five usage periods of NaBH4 hydrolysis. Ultimatley, Cu:Fe (1:1) stablized Triton-X-100 nano catalyst can be utilized as an active and stable catalyst for NaBH4 hydrolysis and H2 generation.

Palladium (Pd)-SiO2 catalysts coated porous stainless steel (PSS)/NaX nanozeolites membranes were prepared via the sol–gel method and their application were evaluated for hydrogen separation. The hydrothermally synthesized NaX nanozeolite was coated by vacuum-assisted method on the PSS surface. The morphology of membranes were characterized using SEM analysis. The Box-Behnken design was used to determination the relationship between the variable input synthesis and process parameters such as: NaX content (0.5-1.5 g), Pd percentage (5-15 %), pressure difference (2-4 bar) and temperature (350-450 ˚C) and the corresponding output parameters including: hydrogen permeation flux, HPF and H2/N2 ideal gas selectivity, IGS. By optimization of the parameters, the experimental maximum hydrogen permeation flux and ideal selectivity were found to be 1.2×10-7 and 720 respectively. Moreover, the performance of the fabricated membrane were investigated for different mixtures of H2/N2 in the optimum condition. The results indicated that hydrogen fluxes and H2/N2 ideal selectivity were decreased by increasing in N2 content. The obtained results suggest that the simultaneous optimization of synthetic and process parameters could be effective for the performance enhancement of Pd-based membranes for hydrogen separation.

Galvanic replacement reactions are a special method for the synthesis of multi-nucleus nanoparticles of various metals within the bed of clinoptilolite. In this method, first, zinc metal cation (Zn +2) after replacing on the clinoptilolite bed was reduced to zinc metal nanoparticles using sodium borohydride salt. Then, the iron (Fe +2) and copper (Cu +2) salts with zinc metal nanoparticles were located on the clinoptilolite bed participate in the oxidation and reduction reactions by citing the potential of various cations in the electrochemical series. The result of these reactions is the formation of deposits of iron and copper nanoparticles on zinc nanoparticles. The selection of appropriate concentrations of cations and determination of the cause of stopping the growth of nanoparticles in each step was carried out by determining appropriate concentrations. XRD, FT-IR, TEM and SEM techniques were used to prove the various stages of work. The effect of the presence and absence of clinoptilolite on increasing the antimicrobial properties of zinc/ iron/ copper three-nucleus nanocomposites and also stability in aquatic environments using bacterial E-coli and Pasteurella specimens have been investigated.

In this study, a new cellulose-based nano-adsorbent was synthesized using a simple method. The synthesized adsorbent was characterized using FT-IR, FESEM and EDX analyses. Adsorption characteristics of epoxy-triazine-modified cellulose nan-adsorbent were compared with cellulose for the removal of malachite green dye from aqueous media. The effects of surface improvement on the adsorption of organic adsorptive were studied by considering various parameters such as contact time, adsorbent dosage, pH, and temperature. The obtained results indicated that the pseudo-second-order model and Freundlich isotherm model well describe the dye adsorption process on the nano-adsorbent. The maximum adsorption capacity of MG on the nano-adsorbent at 45 ˚C was found to be 49.26 mg/g. Furthermore, the calculated thermodynamic parameters showed that the adsorption process of the MG dye was endothermic and associated with an increase in entropy.

In this Study, various carbon nanostructures (nanospheres, nanorods, nanotubes and Graphene quantum dots) were synthesized by carbonization of bituminous coal (less than 44 micron) in solid phase. Since synthesis has taken place in the solid phase, this method has been named the catalytic chemical solid synthesis. Carbon nanospheres (50-60 nm in diameter) and Carbon nanotubes (outer diameter: 20-30nm) were synthesized in the presence of Ferrocene as catalyst, carbonization time of one hour and at carbonization temperature of 650°C and 800°C respectively. The change in the type of catalyst from ferrocene to magnetite nanoparticles (Fe3O4, 50-70 nm in diameter) at 800°C ;as the growth temperature of carbon nanostructures;, resulted in the synthesis of carbon nanorods (60-80 nm in diameter). Without catalysts, the growing nanostructures were not observed at carboniztion temperatures of 650°C, 800°C and 950°C. However, with acid preparation, an increase in carbonization temperature from 800°C to 950°C and an increase in carbonization time from 1 hour to 5 hours, the graphene quantum dots were observed. Samples were analyzed by scanning and transmission electron microscopy, X-ray diffraction, Energy-dispersive X-ray and ultraviolet spectroscopy. The results show that the maximum peak UV-visible spectrum of carbon nanospheres, grown nanostructures and graphene quantum dots are 214, 266 and above 300 nm, respectively.The diameters of carbon nanotubes and nanorods are in the range of iron nanoparticles (20-50 nm in diameter); due to the ferrocene decomposition; and magnetite nanoparticles(60-80 nm in diameter) respectively.

Uranium is the most important material in the nuclear fuel cycle that produces in the various stages of uranium production and processing research and after-use in reactors, as well as laboratory researches as uranium wastage. The uranium in these wastages is valuable and may cause radiation problems if they enter the environment, so their separation is essential. The solvent extraction method is one of the most important separation methods in the nuclear industry that produced uranium components from wastages is recovered using this method in the current study. After identifying the presented components in the wastage, the amount of each component was determined by using Inductively Coupled Spectrometry (ICP) analysis and finally the type of present uranium compound in the wastage was specified. According to the desired compound, the extraction experiments were performed with two different solvents of trioctylamine (TOA) and di-2-ethylhexyl phosphoric acid (D2EHPA) which the extraction percentages were achieved 96.12% and 99.01%, respectively. Also, the effects of extractant type, extraction temperature, acid concentration, extractant concentration, initial uranium concentration, diluent type, aqueous to organic phase ratio, phase mixing time on extraction percentage as well as the effect of various rinses on the reverse process were investigated.

In this study, coprecipitation has been used to prepare alumina nanoparticles. In order to do that first, the effect of aluminium salt and precipitating agent on the specific surface of alumina was studied. Then under an optimized condition, the effect of reaction temperature on phase changes and its specific surface were studied. Generally in order to prepare different phases of alumina nanoparticles, crystalline boehmite was prepared by heating the gelatinous white precipitate which first formed when precipitating agent was added to acid solutions of aluminium salt and finally, by dehydration of crystalline boehmite, nanoparticles of alumina were obtained with different phases. Different physical and chemical tests such as X-ray diffraction (XRD), X-ray fluorescence (XRF), specific surface area measurement (BET), scanning electron microscope (SEM), transmission electron microscope (TEM) and thermogravimetric analysis (TGA) were performed on prepared alumina nanoparticles. The results show that using aluminium nitrate salt and ammonia as precipitating agent yields alumina with the best specific surface area (211 m2/g). Also alumina which is manufactured by using ammonia and aluminium chloride with 58 m2/g has lowest amount of specific surface area. In addition, it was found that after calcinations at 550 °C, gamma-alumina phases appear. While with increasing reaction temperature to 1400 °C, the alpha-alumina phase was produced.

Transition metal phosphine complexes have attracted great attention in recent years due to their potential applications in organic synthesis, catalysis, design of new antitumor, antiviral and antibacterial drugs. The unsymmetrical ylides [Ph2P(CH2)nPPh2CHC(O)C6H4(m-NO2)](n = 1 (Y1) and 2 (Y2)) were synthesized in the reaction of BrCH2C(O)C6H4(m-NO2) ketone with 1,2-bis(diphenylphosphino)methane (dppm) and 1,1-bis(diphenylphosphino)ethane (dppe), respectively. These ligands were also reacted with [PdCl2(COD)] (COD = 1,5-cyclooctadiene) to give the palladacycle complexes [PdCl2(Ph2P(CH2)nPPh2CHC(O)C6H4(m-NO2))] (n = 1 (1) and 2 (2)). Characterization of obtained compounds was performed by elemental analysis and IR, 1H, 13C and 31P NMR spectroscopies. The results showed that the coordination of ylide to metal center occurred through the ylidic carbon atom and phosphine group (P,C-coordinated). Biological properties of these compounds were evaluated by MTT, TBA and antioxidant enzyme activity on colon cancer cells (Caco-2). The obtained results demonstrate thatthe studied compounds can be used as an antitumor agent. Evaluation of the survival and activity of antioxidant enzymes in cells expressing the anticancer activity of the studied compounds is due to activation of the antioxidant system in the cells treated with the studied compounds.

The nano photocatalytic ZTOZ was prepared from ZnO and TiO2 stabilization on ZSM-5 zeolite surface and its catalytic activity was investigated to remove Methyl Orange organic dye and was compared with zeolite-ZnO and zeolite- TiO2 nanocatalysts. The properties of the catalysts were determined using BET, X-ray diffraction (XRD), energy dispersive (EDAX) analysis, and scanning electron microscopy (SEM). The images and spectra obtained showed that Titania and ZnO nanoparticles were well placed on the ZSM5 zeolite surface, and the average size of zinc oxide and titania nanocrystals was calculated using the Debye–Scherrer formula, which was 19.13 nanometers. The mean diameter of the ZTOZ photocatalyst cavity was 1.22 nm, which shows the nanoporous photocatalyst synthesized. The Photocatalytic removal of the dye was performed as a function of pH in the range of 3 to 9 and the initial concentration of dye in concentrations of 5-25 mg / L and the catalyst content in values of 0.1 to 0.4 g / L and at ambient temperature. Then it was modeled by a quadratic polynomial equation. The results showed that the amount of removed dye (response) depends on the pH and initial concentration of the dye. The RSM (surface response methodology) method was used to optimize and find optimum amounts for organic dye degradation in a pyrex glass cylindrical reactor with a height of 460 mm and a volume of 1 L. Also, the kinetic of photocatalytic reactions were studied with the assumptions that they follow the Langmuir-Hinchlood equation and the first-order reaction.

In this research, γ –butyrolactones were prepared using a green, mild, effective and simple method through multi-component synthesis of pyrazole carbaldehyde or indole-3-carbaldehyde, ethylpyruvate and N-bromosuccinimide. The mechanistical pathway for this reaction includes bromination reaction, condensation reaction followed by intra-molecular cyclization. This methodology is completely new and the products were synthesized in short reaction times and high yields. This protocole has advantages as simple method, aqeous media, and reduced environmentally consequences. All of the synthesized compounds were characterized by melting points, infra-red spectroscopy, nuclear magnetic resonance (1H NMR, 13C NMR) and elemental analysis. The novelty of this protocole combined with the novelty of the synthesized compounds is the other highlights of this procedure.

Asphaltene is one of the compounds in crude oil with the heaviest fraction, which causes it to settle and deposit on reservoir or extraction pipes. Various methods have been proposed for its severance or removal so far, as the adsorption of asphaltene using nanoparticles is one of the most efficient ones. The effects of parameters such as asphaltene concentration, temperature and the amount of adsorbent loaded (ZSM-5 zeolite) were investigated in order to optimize the adsorption process of asphaltenes. The physical and chemical properties of the adsorbents were also investigated by SEM, XRD and FTIR. SEM images showed that the ZSM-5 zeolite nanoparticles are highly efficient in adsorption of asphaltene and become agglomerated after adsorption. XRD and FT-IR analyzes also confirmed the presence of asphaltene in the ZSM-5 zeolite after the adsorption process. The equilibrium data were fitted with the Langmuir and Freundlich isotherms to know the adsorption isotherm. The results showed that the adsorption behavior of asphaltene on ZSM-5 zeolite can be well described using Langmuir isotherm. The kinetic results showed that the asphaltenes were rapidly adsorbed to the zeolite in less than 2 hours. By comparing the pseudo-first-order and pseudo-second-order kinetic models, it can be concluded that the pseudo-second-order kinetic model well predicts the kinetic behavior of asphaltene adsorption on ZSM-5 zeolite nanoparticles.

In this research, dispersive micro-solid phase extraction (Dμ-SPE) method based on graphene oxide (GO) sorbent, as a green, accurate and efficient method has been applied for extraction/preconcentration and determination of thymol. At first, graphene oxide was synthesized and characterized by techniques including UV-Vis spectrophotometry, Fourier transforms (FT-IR) and X-ray diffraction (XRD). The effects of various parameters such as pH of the solution, stirring time, amount of adsorbent and the concentration of thymol by the Box–Behnken design method to determine the effective parameters and interactions and to optimize these parameters in the synthesized absorbent performance for determination of thymol was investigated. The highest absorbance of thymol in the optimal conditions; pH = 4, the initial concentration of 30 ng mL-1 of thymol, adsorbent amount of 20 mg and stirring time of 28 min was obtained. Under optimum conditions, the dynamic linear range, limit of detection (LOD) and limit of quantification (LOQ) were 15-600, 4.5 and 14.85 ng mL−1, respectively. Also, the relative standard deviation (RSD, %) of the method for 300 ng mL−1 of thymol, 4.6% (n = 5) was obtained. Finally, the proposed method was successfully applied for extraction and determination of thymol in honey and mouthwash samples.

Introducing new and green methods and finding environmentally friendly solvents in the synthesis of organic compounds is very important. In this study, the synthesis of [1,3] dithiine derivatives using the glycerol: potassium carbonate as deep eutectic solvent was investigated, in addition, the antibacterial effects of the synthesized compounds against two bacterial strains named Edwardsiella tarda and Lactococcus garvieae according to the CLSI standard using microdilution broth base on inhibition zone diameter (IZD), minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were tested. The results showed that glycerol: potassium carbonate could be used as a green solvent in the synthesis of [1,3] dithiine derivatives and the results of antibacterial activities against study also showed that these compounds, especially f5, were capable of inhibiting Edwardsiella tarda and Lactococcus garvieae at concentrations of 64 and 8 μg / ml, respectively. In addition, it was demonstrated that there was a clear relationship between the structure of the derivatives and the antibacterial activity, with the highest effect being on the chlorine-containing compounds, followed by chlorine, bromine, and nitrogen.

In this paper nanoparticles, La0.6Sr0.4MnO3 via microwave radiation method is provided. The structural, magnetic, optical and photocatalyst properties by X-ray diffraction (XRD), Transmission electron microscope(TEM), Fourier transform infrared spectroscopy (FTIR), Vibrational sample magnetometer (VSM) and UV–Vis spectroscopy (UV-Vis) were studied. Lattice constants, cell volume, and space group as well as length and angle of bonds obtained by XRD analysis. Using the UV-Visible spectrometer, an examination of the particle absorption spectrum confirmed the existence of a band gap like semiconductors at about 1.8 eV. The degradation of nanoparticles on methyl orange dye under visible light evaluated about 83% in 50 minutes.

A new hetero-dinuclear complex [(Sr(OH2)6Cu(H2O)4 Sr2 (dipic)4(OH2)2]n.nH2O (CS) that dipic2- is pyridine-2,6-dicarboxylato has been synthesized under ultrasonic irradiation. The structure of the CS complex has been fully characterized by elemental analysis, Fourier transforms infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential thermal analysis (DTA) and single-crystal X-ray diffraction (SC-XRD). The results of crystallography analysis revealed that this complex crystallizes in a triclinic system with space group P -1. It also confirms the large number of H-O ... O hydrogen bonds play a key role in the creation of the 3D network. The Sr-Cu/SiO2 nano-catalyst was prepared by thermal decomposition of CS complex at 600ºC in the presence of silica support. In addition, reference catalysts of Cu-Sr/SiO2 were prepared by co-precipitation and impregnation methods and characterized by FT-IR spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and specific surface area (BET). The results of these studies show that the catalyst obtained by the thermal decomposition of the CS complex has smaller particle size and larger specific surface area than the two reference catalysts. In order to produce hydrogen gas, a water-gas shift reaction (WGS) was performed on the surface of Cu-Sr/SiO2 nanocatalysts in the temperature range of 300-420ºC. Examination of the effect of temperature shows that at 380ºC the catalytic activity of all three catalysts is at its highest. The highest catalytic performance was achieved by nanocatalyst that derived from CS complex. This high catalytic performance can be attributed to the physicochemical properties of this catalyst such as smaller particle size and higher specific surface area.

Sulfur nanoparticles were synthesized via W/O microemulsion method. A comparison study was performed between synthesized sulfur nanoparticles and sulfur micro particles for extraction and preconcentration of nickel ions from different water samples prior to determination by FAAS. The effects of the analytical parameters including pH of the sample solution, sample matrix, eluting solution conditions, flow rate of sample solution, sample volume and interfering ions were investigated for each adsorbent and the optimum values were obtained. The effect of the size of sulfur adsorbent on the extraction efficiency was evaluated. Under the optimum experimental conditions, preconcentration factor, analytical detection limit, adsorption capacity, reusability of the sorbent and flow rate of sample solution were obtained for sulfur microparticles as100, 0.00180 µg/mL, 15.75µg/g, maximum 10 cycles and 1 ml/min respectively. Whether, using sulfur nano particles these amounts were obtained as 166.67, 0.00108 µg/ml, 30.08 µg/g, >70 cycles and 5 ml/min, respectively. These results showed that, sulfur nano particles adsorbent will cause to higher preconcentration factor, lower detection limit, higher adsorption capacity, more reusability of the sorbent and faster extraction of the analyte.The proposed method was applied for determination of nickel ions in tap, river and spring water samples using each of these adsorbents.

An efficient and green approach was developed for the synthesis of various derivatives of tetrahydrobenzo[b]pyran and 3,4-dihydropyrano[c]chromene in the presence of Dendrimer-PWAn as nanocatalyst at ambient temperature through a one-pot three-component reaction between aromatic aldehydes, malononitrile, and dimedone or 4-hydroxycoumarin in an aqueous media under ultrasound irradiation. In order to prepare this catalyst, H3PW12O40 (PWAn) nanoparticles provided by a solvo-thermal method were encapsulated into dendritic polymer-supported on nanosilica. The catalyst is mesoporous and has a particle size of 40 nm. The mean pore diameter, BET surface area and pore volume are 6.1 nm, 479 m2/g and 0.6 cm3, respectively. The amounts of PWAn immobilized on the nanocatalyst was found to be 39.7 wt% (0.14 mmol/g). The developed method is not only suitable for aromatic aldehydes but also successfully used for acid sensitive heteroaromatic aldehydes, and the corresponding products were synthesized with high purity in high yield, and short reaction times. This new method has significant advantages such as operational simplicity, high efficiency, short reaction time and lack of elaborate workup or tedious purification procedures. In addition, excellent yields in a mild environment, thermal stability, and simple catalyst separation make it a suitable alternative to other heterogeneous catalysts. Also, this catalyst can be easily recycled through simple filtration or centrifugation and used for six consecutive periods without significant reduction in activity.

In this study, the SBA-15 nanoparticles were functionalized with (3-Chloropropyl) triethoxysilane and then with the thiocarbohydrazide organic ligand (TCH@SBA-15). Nickel acetate ions were then stabilized on silicate nanosupport (Ni/TCH@SBA-15). The prepared nanocomposite as an organic-metal hybrid was identified using FT-IR, SEM, TEM, XRD, EDAX and BET analysis. The Ni/TCH@SBA-15 nanoparticles were used as efficient and heterogeneous nanocatalysts for the easy and effective synthesis of 2-aryl benzimidazoles. In this catalytic process, benzimidazole heterocycles were obtained from the condensation reaction of different 1,2-phenylenediamine derivatives and various aromatic aldehydes in solvent-free conditions in excellent yields. This green approach can provide a new route for the preparation of all kinds of organic heterocycles.