JOURNAL OF APPLIED CHEMISTRY
Year:2019 | Volume:14 | Issue:52|Papers Count:32

A facile and sensitive method was used to fabricate a novel sensor for the determination of naproxen on the surface of multi-walled carbon nanotubes modified NiCuFe2O4 paste electrode (MWCNTs/NiCuFe2O4/CPE). Adding NiCuFe2O4 to MWCNTs effectively increased the real surface area, and most importantly, amplified the electron transfer. The surface analyses techniques perfectly certified that MWCNTs and spinel were well dispersed in graphite matrix. According to the results, MWCNTs/NiCuFe2O4/CPE produced a sharp peak for naproxen oxidation at about +0. 93 vs Ag/AgCl reference electrode at pH 5. 0. The proposed electrode revealed a linear response over 0. 1-480 µ M with a detection limit of 0. 05 µ M. Finally, this electrode also has the ability to determine naproxen in the presence of acetaminophen without any interference. The brilliant properties of modified electrode such as its lack of toxicity, simplicity of fabrication, and relative inexpensiveness showed that it has feasible to determine naproxen in biological samples.

A new potentially bidentate Schiff base ligand was synthesized from condensation reaction between ethylenediamine and 4-iodobenzaldehyde. The crystal structure of the compound was studied by single-crystal X-ray diffraction and it was shown that the compound was crystallized in monoclinic system with space group P21/n. In the crstal structure, the Schiff base molecule was located on special position with center of inversion in the middle of the C-C bond of the diamine segment. The intermolecular interaction energies of the interacting units were calculated by the theoretical calculations in the crystal structure. The theoretical calculations for interaction energies of the formed dimers from crystal structure were calculated by Gaussian program.

The purpose of this study is the synthesis of molecularly imprinted polymer (MIP) selective to cephalexin. The three-dimensional molecularly imprinted polymer networks were synthesized by radical polymerization of the template: cephalexin, the functional monomer: methacrylic acid and the cross-linker: ethylene glycol di-methacrylate. Then, during the extraction process, the template was separated and thus, imprinted nano pore polymer network was prepared. Synthetic polymer properties were investigated by infrared spectra (FTIR) and scanning electron microscopy (SEM) images. Cephalexin was extracted by magnetic dispersive solid-phase extraction and determined with high performance liquid chromatography (HPLC) technique. Various parameters which could affect the extraction performance were optimized to achieve the high recovery rates. Under the optimal conditions, the limit of detection 0. 005 µ g mL-1 and the relative standard deviation (RSD) 3. 18% were obtained. The calibration curve was determined in the range of 0. 01-15 µ g mL-1 with a correlation coefficient of 0. 996. The results showed that this method has efficiency and high repeatability for measuring and separating trace cephalexin in real samples.

In this work, an electrochemical sensor based on carbon paste electrode modified with Au nanoparticle and 1-methyl-3-octylimidazolium chloride was fabricated as a sensor for determination of methyldopa. Au nanoparticle synthesized by Nettle extract and characterized by UV-Vis and TEM methods. The modified electrode showed good electrical conductivity for methyldopa signal. The effect of pH showed that electro-oxidation of methyldopa occurred with two electrons and two protons. The fabricated sensor showed the dynamic range 0.08-550 μM with detection limit 0.04 μM for determination of methyldopa. In the final step, the fabricated sensor was used successfully for determination of methyldopa in tablet and urine samples.

The three component reaction of ammonium acetate with 3-formyl chroman and pre-prepared ketones in absolute ethanol as a solvent, some derivatives of 1, 3-diazabicyclo[3. 1, . 0]hex-3-en-2-one-2-yl-4H-chromen-4-one heterocycless were synthesized for the first time. The ketoaziridines were synthesized from the reaction of chalcones with bromine in chloroform and then the reaction of the resulting ketodiramide compounds with ethanolic solution of ammonia. The structure of new synthesized photochemic compounds was characthrized using infrared, magnetic magnetic resonance, and ultraviolet-visible. The results of the study of UV-Vis spectra of the newly synthesized photochromic compounds at different times after UV irradiation indicate that the photochemic behavior in the solution state. New derivatives exhibited interesting photochemic behavior in the crystalline phase and solution state.

A simple, efficient and versatile procedure for the synthesis of the 1-Aryl-1H-tetrazols using reaction between triethyl orthoformate, sodium azid and aryl amines in the presence of the ZrOCl2. 8H2O as catalyst is introduced. The reaction is carried out at acetic acid as solvent under low temperature and gets pure products in high yields. In continue the quantum chemical computations were done on products using density functional theory. The M062X/6-31G(d) used as the method and basis set for all calculations. Geometrical structures, thermodynamical properties, frontier molecular orbitals (HOMO and LUMO) and electrostatic potential maps of the products were obtained and analyzed. The results showed that the both of the maximum and minimum electrostatic potential regions are located on the tetrazol ring therefore for both of the nucleophilic and electrophilic reactions the tetrazol ring will be prior to the phenyl one.

In this research, clinoptilolite was modified in situ by using cetylpyridinium chloride and used for solid phase extraction-determination of sulfasalazine. Characteristics of the adsorbent were determined by scanning electron microscopy, X-ray diffraction spectroscopy, thermogravimetric analysis, EDX-mapping and Fourier transform-infrared spectroscopy. The prepared adsorbent is able to interact through non-polar and ionic interactions, due to having cetylpyridinium moieties. Cetylpyridinium chloride concentration, pH, amount of clinoptilolite, extraction time, composition and volume of the eluent, elution time and ionic strength as the affecting parameters were evaluated, and the best conditions were selected to achieve the maximum sensitivity for the spectrophotometric determination of sulfasalazine at 450 nm. Under the optimum conditions, linear range and limit of detection for sulfasalazine were 0. 02-5 µ mol L-1 and 4 nmol L-1, respectively. Sulfasalazine in different pharmaceutical formulations was determined by the method, successfully. As well, various soil and environmental water samples were analyzed to evaluate the applicability of the established method.

Nanocomposite anion exchange membranes were prepared using polymeric blend of poly(vinyl chloride) and poly(methylmetacrylate) by solution casting method. Also functionalized carbon nanotubes were used as additive. The carbon nanotube nanoparticles were modified using acid mixtures and ethylenediamine solution and then the structure and morphology of prepared functionalized carbon nanotubes were studied using infrared spectroscopy (FT-IR) and field-emission scanning electron microscopy (FE-SEM). The study of the physicochemical and electrochemical properties of prepared membranes showed that the water content, ion exchange capacity, membrane potential, transport number, surface charge density and permselectivity of them were improved by adding up to2% by weight of carbon nanotubes. Also, the permeability, flux, electrical resistance and chemical stability of prepared membranes with carbon nanotube increased compared to the nanotube-free membranes. In fact, the high active level and the effect of the functionalized carbon nanotube on increasing the hydrophilicity and the transfer properties of the membranes have created suitable ion channels and facilitated ion transport. By adding nanoparticles up to 4% by weight, the electrochemical properties of the prepared membranes were reduced slightly. This can be attributed to the blockade of functional groups by nanoparticles and the accumulation of carbon nanotubes.

In this research, poly organo silsesquioxane with a functional group which contains the chlorine atom has been prepared to support a functionalized phthalocyanine complex. The prepared catalyst has been characterized with powder X-ray diffraction pattern, field emission scanning electron microscopy and infrared spectroscopy. This catalyst was then used for catalytic oxidation of benzyl alcohol and some parameters in this model reaction have been optimized such as the type of oxidant and solvent, amount of catalyst, reaction temperature and time. It was found that the optimum conditions are 40 mg catalyst in acetonitrile as solvent with tert-butylhydroperoxide as oxidant at 82 C which gives 70% yield.

A highly sensitive electrochemical sensor was fabricated based on ionic liquid and NiFe2O4 nanoparticles modified carbon paste electrode for determination of mangiferin. The modified electrode exhibited excellent electrocatalytic activity towards the oxidations mangiferin in phosphate buffer solution (pH 7. 0). Cyclic voltammetry (CV), chronoamperometry (CHA) and differential pulse voltammetry (DPV) were used to investigate the electrochemical reaction of mangiferin at the modified electrode. It dramatically enhanced mangiferin oxidation current and shifted its potential towards less positive potential when compared to bare CPE. The peak current vs. mangiferin concentration diagram was found to be linear in range of 0. 1 to 500. 0 μ M with the respective slope of 0. 0576 μ A μ M-1. The detection limit obtained by DPV was 0. 09 μ M (S/N = 3). The proposed sensor was proved to be applicable for the determination of the mangiferin in urine samples.

In this research, the Cu(II) doped ZnO/ZnAl2O4 was prepared. The sample was characterized using X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM) equipped with Energy dispersive X-ray spectroscopy (EDX) and Inductivity coupled plasma atomic emission spectroscopy (ICP-AES). Efficiency of the sample as an adsorbent for anionic and cationic dyes removal such as Methyl orange, Congo red, Methylene blue and dyes mixture of Methylene blue and Methyl orange in aqueous solution was investigated. Furthermore, efficiency of this sample with undoped sample was compared. Pseudo-first order and pseudo-second order kinetic models were examined. The results showed that the Cu(II) doped ZnO/ZnAl2O4 sample is a promising candidate for removal of Methyl orange anionic dye from wastewater.

In this study, a novel chitosan, graphene oxide and MnFe2O4 composite (CS-GO-MnFe2O4) was prepared as a magnetic bioadsorbent for water purification. The morphology, chemical structure and magnetic property of the composite were characterized by FT-IR, XRD, SEM and VSM analysis. The resulting composite shows good adsorption capacity for removal of naphthol blue black (NBB) as an acid dye model, in water. Adsorption of NBB onto CS-GO-MnFe2O4 was investigated with respect to pH, adsorption time, initial NBB concentration and temperature. The study of the adsorption isotherms and kinetics at the optimum pH 6. 0, revealed that the pseudo-second-order kinetic and Langmuir isotherm model well-described kinetics and equilibrium adsorptions, respectively. The values of thermodynamic parameters (Δ G, Δ H and Δ S) indicated that the adsorption process is spontaneous and exothermic in nature. The results show that, more than 80% color removal could be achieved in 60 min contact time with 40 mg L− 1 of initial concentrations.

In this study, graphene and magnetic graphene-based nano-absorbents were synthesized by Hummers method and was used in order to removal of BTEX from gasoline. The structural properties of nanoabsorbents were characterized with X-ray diffraction (XRD) and Scanning electron microscope (SEM). The absorption of pollutants were measured using UV-Vis spectrophotometer. The studied variables were the absorbent concentration, the contact time, the initial concentration of Pollutants and temprauchere. Adsorption isotherms were drawn with Longmuir, Freundlich, temkin, Freundlich-Longmuir, Dubnin-Randkovich )D-R( and Redlich-Peterson )R-P( models. The maximum adsorption capacity for BTEX was determined by graphene 56. 8 mg/g and by magnetic graphene 69. 6 mg/g. Experimental and Statistical results was showed that magnetic graphene has better performance than graphene. Kinetic models, based on the assumption of the pseudo-first-order and pseudo-second-order models, were applied to examine the kinetics of the adsorption. The results showed that kinetic data followed closely to the first-second-order model.

In the present work, NRGO and Ag/NRGO catalysts were synthesized using eco-friendly reducing agents. Graphene oxide was prepared as a substrate by electrochemical method. Then, using urea as nitrogen source, it was converted into graphene nitrogen dop under a temperature of 160 ° C and used as a silver bed. The presence of nitrogen in the graphene structure results in a better dispersion of the silver metal on graphene and prevents the accumulation of them. To investigate the catalytic behavior of electrocatalysts, linear scaling voltammetry test was used in alkaline medium for oxygen regeneration reaction. Ag / NRGO showed better catalytic behavior than the NRGO as the bare substrate. It also showed better kinetic behavior than NRGO.

In this study, the photodegradation of pirimicarb pesticide was investigated in presence of suspended and immobilized TiO2 on a glass plate. The influence of operational parameters (initial concentration of pirimicarb, pH and light intensity) on the photocatalytic activity of TiO2 and the kinetic of reaction was investigated. The results show that TiO2 as a photocatalyst has a good efficiency in the presence of UV-C light to remove pirimicarb from aqueous solution. The favorable conditions obtained for the photodegradation of pirimicarb were pH= 6, light intensity = 17 Wm− 2, and [pirimicarb]0 = 40 mgL− 1 in both the systems. Also, in the slurry system, the most suitable catalyst dosage was 300 mgL− 1. The kinetic examination, following the pseudo fi rst-order reaction kinetics, was made based on the Langmuir– Hinshelwood model. Also, the decreasing trend of total organic carbon (TOC) and the increasing trend of inorganic carbon (IC) over time and during the photocatalytic process, indicates the oxidation of organic pollutant over the reaction time.

In this paper a solid-state pH sensor is proposed based on cobalt oxide nanoparticles electrodeposited on carbon ceramic electrode. The morphology of carbon ceramic electrode coated with cobalt oxide nanoparticles was studied by scanning electron microscopy (SEM). It showed that the particles were deposited in nano size and uniformly on electrode surface. The modified electrode showed Nernstian behavior with a slope of 74. 04 mV/pH in the wide pH range of 1. 5 – 12. The ion selectivity of the pH sensor with respect to Li+, Na+ and K+ were tested and the values of-11. 9,-12. 4 and-12. 1 were obtained for 〖 log K〗 _(H^+, 〖 Li〗 ^+)^pot, 〖 log K〗 _(H^+, 〖 Na〗 ^+)^pot and 〖 log K〗 _(H^+, K^+)^pot, respectively. Some important parameters including repeatability, reproducibility, and response time of the sensor were studied. In order to evaluate the applicability of the sensor a number of acid– base titrations were done. Also, in order to evaluate the efficiency of the sensor for measuring the pH in complex matrixes some real samples were tested. Comparing statistical results of modified electrode with a glass pH electrode by using t-test indicated that there is no significant difference in concerning accuracy. The obtained results were in good agreement with a conventional glass pH electrode.

A modified electrochemical sensor based on carbon paste electrode modified with CoFe2O4 nanoparticle and 1-Butyl-3-methylimidazolium tetrafluoroborate was fabricated for benserazide determination. In the first step, CoFe2O4 nanoparticle were synthesized by co-precipitation method and characterized by TEM method. In continuous and at optimum condition, the prepared sensor showed dynamic range between 0. 1-350. 0 μ M with detection limit 0. 05μ M for determination of benserazide. The diffusion coefficient was determined by chronoamperometric method. The proposed sensor showed good selectivity for determination of benserazide in the presence of usual interferences. Finally, the modified sensor was used for determination of benserazide in pharmaceutical and biological samples and showed the high ability for analysis of this drug in real samples.

In this research, removal of the lead ion in the diffusion dialysis was investigated. The membranes was prepared using sulfonated polyethersulfone at 12, 14 and 18 wt. % concentration by the phase inversion method. Their physical properties including the ion exchange capacity, water content, porosity and thickness of membranes were investigated. For investigation of cation exchange membranes performance, experimental design was developed. Three parameters in three levels were selected. By using signal to noise ratio (SNR), the parameter which had the most effect on the lead ion transport was the concentration of the lead ion in the feed. Furthermore, the effect of sodium ion presence in the feed on the lead ion transport was studied. The effect of addition of nanoclay to the optimum membrane was studied. In the optimum condition, the feed with 100 ppm and 5000 ppm concentrations had the flux of 4. 08×10-5 and 6. 56×10-2 mmol/s m2, respectively.

In this study, chemical modification of MCM-41 mesoporous structure with {3-(2-aminoethylamino) propyl} trimetoxysilane was used as adsorbent for removal of Rhodamine B and Yellow 13. Adsorbent proficiency in removal of basic dyes was studied with parameters such as sorbent mass, pH, contact time and temperature. The results showed that as sorbent mass in 1-6 mg, contact time in 10-60 min, temperature in 25-65 º C increased; removal of dyes increased in 60-100% in values. Optimal conditions were determined as sorbent mass in 6 mg, contact time in 60 min, temperature in 60 º C and pH value in 4 and 8 for Rhodamine B and Yellow 13, respectively. Then, its application was investigated on removal of Rhodamine B and Yellow 13 from pharmacy and textile wastes, respectively. The maximum removal values of Rhodamine B and Yellow 13 in wastes using modified MCM-41 were 97. 63 and 96. 11%, respectively.

In this study, magnetic nanoparticles (Fe3O4 NPs) and magnetic supported on functionalized activated carbon (Fe3O4/AC NPs) were synthesized by co-precipitation method under N2 gas. These nanocatalysts were characterized by Fourier Transform Infrared Spectrometry (FT-IR), X-Ray Diffusion (XRD), adsorption and desorption isotherms of N2 (BET) and Vibrating Sample Magnetometer (VSM). The catalytic activity of these nanocatalysts in Fenton heterogeneous process was evaluated by the degradation of reactive red ME4BL (RR ME4BL) textile dye as a model of organic pollutant. The effect of parameters such as H2O2 concentration, RR ME4BL concentration, the amount of catalyst, pH and temperature in the degradation of dye for Fenton process. At the optimum conditions, H2O2 (4mmolL-1), Fe3O4 NPs (4mg), RR ME4BL (100mgL-1) and pH=3 at room temperature, the dye was degraded 93%. The kinetics of degradation of RR ME4BL by Fenton processes was also studied and the results showed that the oxidation of RR ME4BL follows the pseudo-first order.

In the present study, Kit-6 silica mesoporous was chemically synthesized on the surface of silica coated magnetite core and functionalized by amine groups to obtained Fe3O4@SiO2@Kit-6 MNCs. The amino functional groups were chemically bonded on the surface of synthesized MNCs by post toluene reflux synthesis method and after characterization by XRD, FT-IR, EDX and SEM, it’ s effectiveness as an adsorbent for the removal of reactive yellow160 dye from aqueous solutions was evaluated. Experimental factors affecting the dye removal efficiency such as sorbent weight (0. 08 g), ionic strength (without salt addition), pH (4), sample volume (10 ml), and contact time (20 min) were optimized by Taguchi experimental design. The results revealed that removal efficiency of reactive yellow was more than 97% in optimal conditions. Pseudo first order, pseudo second order, intraparticle diffusion and Ilovich models were considered to evaluate the rate parameters. Kinetic data were fully fitted to the pseudo-second order kinetic model. Also, the adsorption equilibrium was represented with Langmuir, Freundlich and Temkin isotherm models. The fitting of data for dye sorption onto the Fe3O4@SiO2@Kit-6-NH2 suggested that the Freundlich model gave a better fit than the Langmuir and Temkin models. The results showed that Fe3O4@SiO2@Kit-6 nanocomposite modified with amine groups can be used as an alternative low cost adsorbent for removal of anionic pollutants from aqueous solutions.

In this research, it has been tried to construct a self-healing epoxy based nanocomposite using montmorillonite (MMT) nanoparticles. Urea-formaldehyde microcapsules were made using in-situ polymerization in the presence of Montmorillonite nanoparticles and MMT modified microcapsules were studied using FT-IR and optical microscopy (OM). The analyzes showed that the use of montmorillonite was effective in the preparation of microcapsules and improved their properties. Finally, the epoxy based self-healing nanocomposite was made using MMT nanofiller and DCPD healing agent. Finally thermal stability of self-healing nanocomposite reinforced with clay nanoparticles was investigated using thermal gravimetery analysis as well as mechanical strength before and after damage.

Due to destructive effects of organic chlorides, removal of these compounds from contaminated crude oil and its distillates is very crucial for oil refiners. Despite the importance of this subject, a few researches in this area exist and most of them proposed solutions that are very difficult and costly. Therefore, in this study it is going to introduce sintered alumina nanoparticles as a new suitable adsorbent of organic chlorides from naphtha fraction of contaminated crude oil. The adsorbents were made via sintering 10 to 35 grams of γ-Al2O3 nanoparticles with average particle size of 20 nm at temperature of 773. 15 K for about 4 hours and then, were characterized by XRD, SEM-EDS, and BET analyses. The removal efficiency of the adsorbent at adsorption time of 10 hours reached to more than 60% and 96% for samples with initial concentrations of 105 and 8. 5 mg/L respectively. According to equilibrium investigations, Freundlich isotherm model provided a better fit to the adsorption equilibrium data than other isotherm models. It was also found that for samples with high organic chloride concentrations, the adsorption kinetics followed the pseudo-first-order kinetic equation well while pseudo-second-order kinetic model exhibited better fit to kinetic data of samples with low organic chloride concentration. Above mentioned investigation results implied that the sintered γ-Al2O3 nanoparticles would be an effective adsorbent for adsorption removal of organic chloride from naphtha distillate of crude oil.

The electrochemical coagulation process, or EC, is an electrochemical process that direct electrical current was used to remove pollutants from solution. In this paper, the effect of nanofluids of iron, copper, and zinc metal oxides on electrochemical reaction of heavy cobalt metal removal from the refinery wastewater was investigated. Different tests were performed to achieve the best performance with maximum efficiency. In the meantime, the best performance was achieved at 30 volts and 60 minutes having efficiency up to 52%. In the next step, the tests were performed using iron, copper, and zinc nanoparticles oxides that they could been reduced cobalt values to 73%, 87% and 61% of the initial amounts, respectively. Between used metal oxides, the results show iron oxide nanoparticles could reached to maximum cobalt removal from the wastewater, and after that copper and zinc oxides nanoparticles have high removal efficiency, respectively. Surface response method used to determining the optimum cobalt removal conditions. A quadratic statistical model was presented in terms of experimental parameters. The statistical model predictions from experimental design are in good agreement with experimental data for cobalt removal in this work.