Marjan Tanzifi; Mohsen Mansouri; Maryam Heidarzadeh; Kobra Gheibi
Abstract
In the present study, adsorptive properties of Polyaniline (PAn) were investigated for Amido Black 10B dye in aqueous solution. Different variables, including adsorption time, adsorbent dosage, solution pH and initial dye concentration were changed, and their effects on dye adsorption onto PAn nano-adsorbent ...
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In the present study, adsorptive properties of Polyaniline (PAn) were investigated for Amido Black 10B dye in aqueous solution. Different variables, including adsorption time, adsorbent dosage, solution pH and initial dye concentration were changed, and their effects on dye adsorption onto PAn nano-adsorbent were investigated. The study yielded the result that an increase in pH decreases the adsorption efficiency of nano-adsorbent. Also, Dye adsorption capacity increased with increase in the initial dye concentration. Optimum adsorption time and nano-adsorbent dosage were obtained 30 min and 0.1 gr, respectively. Kinetic studies illustrated that the Amido Black 10B dye adsorption process onto PAn nano-adsorbent followed the pseudo-second-order model, which indicates that the adsorption process is chemisorption-controlled. Also, adsorption equilibrium data were fitted to Freundlich isotherm. The maximum dye adsorption capacity, predicted by the Langmuir isotherm, was 142.85 mg/g. Moreover, Dubinin-Radushkevich isotherm showed that the adsorption of dye onto PAn nano-adsorbent is a chemisorption process.
Amirali Abbasi
Abstract
Density functional theory calculations were carried out to investigate the adsorption behaviors and electronic structures of SO2 and O3 molecules on the pristine boron nitride nanotubes. The structural and electronic properties of the studied systems were investigated in view of the adsorption energies, ...
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Density functional theory calculations were carried out to investigate the adsorption behaviors and electronic structures of SO2 and O3 molecules on the pristine boron nitride nanotubes. The structural and electronic properties of the studied systems were investigated in view of the adsorption energies, band structures and molecular orbitals. Various adsorption positions of gas molecules on the boron nitride nanotubes were examined in detail. The band structure calculations indicate that the pristine BN nanotube works as a wide band gap semiconductor, and can be applied as an efficient candidate for SO2 and O3 sensing purposes. NBO analysis reveals that SO2 acts as a charge donor, whereas O3 molecule behaves as a charge acceptor from the BN nanotube. Molecular orbital calculations indicate that the LUMOs were dominant on the nanotube surface, whereas the electronic densities in the HOMOs were mainly distributed over the adsorbed SO2 and O3 molecules. Moreover, the charge density difference calculations indicate charge accumulation on the adsorbed gas molecule.
Taher Yousefi; Hamid Raza Moazami; Hamid Reza Mahmudian; Meisam Torab-Mostaedi; Mohammad Ali Moosavian
Abstract
In the current research work the Iranian natural zeolite (clinoptililite) was modified with Cobalt Hexacyanoferrate nanopatricles. The natural and Cobalt Hexacyanoferrat modifed zeolites were characterized by FTIR and SEM techniques and were empolyed as an adsorbent for removal Cd(II) ions from ...
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In the current research work the Iranian natural zeolite (clinoptililite) was modified with Cobalt Hexacyanoferrate nanopatricles. The natural and Cobalt Hexacyanoferrat modifed zeolites were characterized by FTIR and SEM techniques and were empolyed as an adsorbent for removal Cd(II) ions from aqueous sloution. The adsorption expriments were performed in bach mode. The Cd(II) sorption capacity of Cobalt Hexacyanoferrat modified zeolite was 51 mg g-1. The effect of influceing factors such as time, temperature and initial concentration were investigated. A fast sorption was observed in the initial contact time and equilibrium was achieved in less than 100 min. The equilibrium adsorption data for Cd (II) were better fitted to the Longmuir adsorption isotherm model. The increase in temperature has a slight positive effect on the uptake of Cd(II) ions. The results indicated that the Cobalt Hexacyanoferrate nanopatricles modified natural zeolite has effective potential for the adsorption of Cd(II) from the wastewater.
Maryam Adimi; Maziar mohammadpour; Hassan Fathinejadjirandehi
Abstract
This research reported a study on COD removal from petrochemical wastewater (ml/l) by the electro-Fenton process via the effects of different parameters such as reaction time, current density, pH, H2O2/Fe2+ molar ratio, and volume fraction of H2O2. For this purpose, first, the Nanopores on the aluminum ...
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This research reported a study on COD removal from petrochemical wastewater (ml/l) by the electro-Fenton process via the effects of different parameters such as reaction time, current density, pH, H2O2/Fe2+ molar ratio, and volume fraction of H2O2. For this purpose, first, the Nanopores on the aluminum electrode surface were prepared as the AAO films were fabricated using the two-step anodization of 6063 aluminum alloy sheets at ambient temperature in sulfuric acid and phosphoric acid electrolyte solutions respectively.The nanostructures created on electrode confirmed by Scanning Electron Microscopy (SEM). Then, Efficiency of electrochemical oxidation process was tested by COD determination via electrolyte cell contain waste water, Fe2+, H2O2 and AAO electrode based on experimental design. The optimum COD removal (65.03%) was obtained at pH of 2.96, the reaction time of 89.51 min, the current density of 69.57 mA, the H2O2/Fe2+ molar ratio of 3.42 and volume fraction of H2O2 to petrochemical wastewater of 1.93 (ml/l).
Mahta Nazari; Bita Ayati
Abstract
This study was conducted to evaluate sodium dodecyl benzene sulfonate removal using electrocoagulation/flotation and photocatalytic nano-TiO2 slurry systems. The parameters which are effective on the surfactant removal were investigated and optimized. Electrocoagulation/flotation system included meshed ...
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This study was conducted to evaluate sodium dodecyl benzene sulfonate removal using electrocoagulation/flotation and photocatalytic nano-TiO2 slurry systems. The parameters which are effective on the surfactant removal were investigated and optimized. Electrocoagulation/flotation system included meshed and mono-polar stainless steel electrodes which installed horizontally. According to the results, after 60 minutes in pH of 8, electrodes distance of 1 cm, initial SDBS concentration of 750 mg/L, SDBS and COD removal rates were achieved to 93.54 and 90%, respectively. In photocatalytic system, during 48 h, SDBS and COD removed 98.7 and 95%, respectively, while pH was around 8, initial concentration of SDBS was 300 mg/L and nano-TiO2 particles concentration was 0.5 mg/L. In the hybrid system, after 12 minutes, SDBS concentration reached to 329 mg/L which entered to the photocatalytic system that resulted in SDBS and COD removal efficiency of 99 and 96.27%, respectively. Compared to the single systems, by using the hybrid system, the removal efficiencies were improved.
Asadollah Mohammadi; Seyed Hossein Mousavi
Abstract
In this work, an efficient photocatalyst based on β-cyclodextrin-glycine-modified TiO2 nanoparticles (TiO2-Gly-βCD NPs) was successfully synthesized. The photocatalytic activity of the prepared TiO2-Gly-βCD was tested on the degradation of methylene blue (MB) and methyl orange ...
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In this work, an efficient photocatalyst based on β-cyclodextrin-glycine-modified TiO2 nanoparticles (TiO2-Gly-βCD NPs) was successfully synthesized. The photocatalytic activity of the prepared TiO2-Gly-βCD was tested on the degradation of methylene blue (MB) and methyl orange (MO) dyes. The enhanced surface properties of TiO2-Gly-βCD photocatalyst generated excellent photocatalytic performance for the photocatalytic degradation of dyes in aqueous solution. These were strongly attributed to the presence of the functional hydroxyl groups and the inner cores of the hydrophobic cavity in β-CD to form inclusion complexes with organic molecules. As compared to the pure TiO2 and TiO2 modified by Gly, the dye degradation rate under UV irradiation was considerably enhanced by TiO2/Gly/βCD as a photocatalyst. In addition, the sonocatalytic degradation of dyes was investigated, and it was found that the ultrasonic waves slightly enhanced the degradation time of dyes. The results indicated that the first-order kinetic model well describes the degradation of MB and MO dyes by TiO2-Gly-βCD. Furthermore, the chemical oxygen demand (COD) values were determined for real industrial wastewater and treated wastewater.
Shahryar Nazarpour Laghani; Azadeh Ebrahimian Pirbazari
Abstract
In this work, multi-walled carbon nanotubes (MWCNTs)/Co-TiO2 nanocomposites were synthesized and investigated for photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP) under visible light. Characterization of photocatalysts was done by means of XRD, FT-IR and SEM/EDX techniques. Obtained results ...
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In this work, multi-walled carbon nanotubes (MWCNTs)/Co-TiO2 nanocomposites were synthesized and investigated for photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP) under visible light. Characterization of photocatalysts was done by means of XRD, FT-IR and SEM/EDX techniques. Obtained results showed cobalt doping can inhibit phase transformation from anatase to rutile and eliminate the recombination of electron-hole pairs. The presence of MWCNTs can both increase the photoactivity and change surface properties to achieve sensitivity to visible light. The optimum mass ratio of MWCNTs and cobalt (Co) dopant in TiO2 was the prominent factor to harvest MWCNTs/Co-TiO2 photocatalyst. The sample containing 3.13 wt% cobalt exhibited the highest activity under visible light for 2,4-DCP degradation, which was completed within 180 min using a 0.1 g/L dose of this photocatalyst in a 40 mg/L solution of the 2,4-DCP. The reactions follow the first-order kinetics. The reaction intermediates were identified by GC–MS technique. GC–MS analysis showed the major intermediates of 2,4-DCP degradation are simple acids like oxalic acid, acetic acid, etc. as the final products.
Ramin Yavari
Abstract
In the present research work, zirconium oxide coated on activated alumina (Al2O3-90, Al2O3-60) were synthesized and used along with their pristine materials to investigate and compare the adsorption behavior of fluoride on them. These material was characterized by BET and X-ray diffraction analyzer. ...
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In the present research work, zirconium oxide coated on activated alumina (Al2O3-90, Al2O3-60) were synthesized and used along with their pristine materials to investigate and compare the adsorption behavior of fluoride on them. These material was characterized by BET and X-ray diffraction analyzer. The obtained results confirmed that the immobilization of ZrO2 particles on the external surface pore of Al2O3-60 and Al2O3-90 has been performed successfully. The results of adsorption behavior study show that among these adsorbents, the synthesized hybrid material “Al2O3-60-ZrO2” has high affinity toward the adsorption of fluoride ions from aqueous solution under ambient condition (36.62 mg.g-1). Adsorption data in all of adsorbents were fitted with Langmuir model and the calculated E value shows that the chemical sorption process is a dominant mechanism in adsorption process. In the first 80 minutes of contact time, the maximum adsorption of fluoride was found to be for these synthesized hybrids” Al2O3-60-ZrO2, Al2O3-90-ZrO2”. The adsorption rate of fluoride ions on these hybrid materials in spite of their initial material was almost independent on pH value in the range 3 to 8. The negative values of ΔG° indicates that the adsorption process of fluoride ions onto these adsorbents is exergonic and will proceed spontaneously. In addition, overall, the obtained results show that the prepared hybrid materials as adsorbents are promising and potential candidate for the adsorption and removal of trace amount of fluoride from nuclear and chemical wastewater.
Atiyeh Yazdani; Mohammad Sayadi; Ava Heidari
Abstract
The green synthesis of palladium oxide nanoparticles using Dictyota indica seaweed extract was investigated. Dictyotales is a large order in the brown algae (class Phaeophyceae). The color of the reaction mixture changed which indicated the formation of palladium oxide nanoparticles. UV-Visible, SEM, ...
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The green synthesis of palladium oxide nanoparticles using Dictyota indica seaweed extract was investigated. Dictyotales is a large order in the brown algae (class Phaeophyceae). The color of the reaction mixture changed which indicated the formation of palladium oxide nanoparticles. UV-Visible, SEM, TEM, XRD, and FTIR analysis determined the characteristics of synthesized nanoparticles. The UV-Visible analysis showed the formation of palladium oxide nanoparticles. SEM and TEM analyses presented the palladium oxide nanoparticles have a spherical shape and based on DLS analysis with the average particle diameter of 19nm. The comparisons of the nanoparticle size with different biological synthesis were studied which revealed this methodology offer smallest size. The crystallographic parameters of the synthesized Pd nanoparticles were as follows: crystalline structure (cubic), space group (Fm-3m), and lattice parameter (a=5.6500, b=5.6500, c=5.6500, α=90, β=90, and γ=90). FTIR analysis indicated the presence of a palladium oxide group in the product. The removal efficacy of cadmium by the palladium oxide nanoparticles was investigated to optimize the pH, contact time, dose of adsorbent and concentration of cadmium. The results showed that optimum conditions for cadmium removal from water were obtained at pH 8, 500 mg/l adsorbent dose and 20 min contact time, wherein in these circumstances the removal of cadmium was 82.82%. The adsorption isotherms primacy was as follows, Langmuir R2=0.9904> Freundlich R2=0.9857> Temkin R2=0.8791.
Mansoor Kazemimoghadam
Abstract
Zeolite membranes have uniform and nano-sized pores, and they separate molecules based on differences in the molecules size and diffusion properties. Different routes used to prepare zeolite composite membranes include growing zeolite layers from gels on porous supports. Our approach to membrane synthesis ...
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Zeolite membranes have uniform and nano-sized pores, and they separate molecules based on differences in the molecules size and diffusion properties. Different routes used to prepare zeolite composite membranes include growing zeolite layers from gels on porous supports. Our approach to membrane synthesis was based on hydrothermally converting films of layered aluminosilicates into zeolite films. In this research, synthesis of nano NaA zeolite membrane from kaolin was investigated. In the first step, kaolin has been calcined at 700 °C to the metakaolinite phase. As a second step, the zeolitisation experiments have been carried out under hydrothermal conditions. The metakaolinite obtained has been reacted with NaOH solutions in autoclaves at 100°C. X-ray diffraction (XRD) patterns of the membranes exhibited peaks corresponding to the support and the zeolite. The morphology of the support and membrane subjected to crystallization was characterized by Scanning electron microscopy (SEM). Separation performance of the NaA membranes was evaluated using pervaporation of water–Ethanol mixtures. The membranes showed high water selectivity in the water–Ethanol mixtures.
Amirali Abbasi; Jaber Jahanbin Sardroodi
Abstract
Density functional theory investigations were conducted in order to study the effects of the adsorption of thiophene on the structural and electronic properties of TiO2 anatase nanoparticles. The ability of pristine and N-doped TiO2 anatase nanoparticles to recognize toxic thiophene was surveyed in detail. ...
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Density functional theory investigations were conducted in order to study the effects of the adsorption of thiophene on the structural and electronic properties of TiO2 anatase nanoparticles. The ability of pristine and N-doped TiO2 anatase nanoparticles to recognize toxic thiophene was surveyed in detail. It was found that thiophene molecule is chemisorbed on the N-doped anatase nanoparticles in S site geometries with large adsorption energy and small distance. By including van der Waals (vdW) interactions between thiophene molecule and TiO2, we found that the adsorption on the N-doped TiO2 is energetically more favorable than the adsorption on the pristine one, suggesting that the nitrogen doping can energetically facilitate the thiophene adsorption on the N-doped nanoparticle. The order of adsorption energy is Parallel(S site)>Perpendicular(S site)>Perpendicular (H site). The interaction between thiophene and N-doped TiO2 can induce substantial variations in the HOMO/LUMO molecular orbitals of the nanoparticle, changing its electrical conductivity, which is helpful for designing the novel sensor and remover devices. Charge analysis based on Mulliken charges reveals that charge is transferred from thiophene molecule to TiO2 nanoparticle.
Ghaffar Torkashvand; Norodin Mirnia; Ali Bahari
Abstract
Template-assist method is one of the most important techniques for synthesize nanostructures , because of more parameters that can be change to fabricate different nanostructures with desired nano-scale features. self- ordered anodic alumina is one of the most important honeycomb structure that can be ...
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Template-assist method is one of the most important techniques for synthesize nanostructures , because of more parameters that can be change to fabricate different nanostructures with desired nano-scale features. self- ordered anodic alumina is one of the most important honeycomb structure that can be used as a template. by using self-ordered nanoporous as a template and hydrothemal process as a deposition technique,different structures like nanowire,nanotube and nanoparticle was fabricated. The effect of surfactant and temperature on the formation of various nano-structures were investigated by SEM (scanning electron microscopy) and EDX (Energy dispersive x- ray) analysis. Electrical properties and I(Current)- Voltage (V)- Gate - source behavior of the samples was measured by four-probe (4- probes) method. Tin oxide nanoparticle array on the surface of alumina membrane used as chemical sensor in case of detecting hydrazine. The obtained results indicate that Alumina doped with tin oxide nanoparticle is suitable for detection of toxic chemicals in water such as hydrazine.
Mehrzad Arjmandi; Majid Peyravi; Mahdi Pourafshari Chenar; Mohsen Jahanshahi; Abolfazl Arjmandi
Abstract
To investigate the adsorption property of H2 and CO2 on the organic ligand of C-MOF-5 (H2BDC) and T-MOF-5 (ZnO-doped H2BDC (ZnO-H2BDC)), Density functional theory (DFT) method was performed. First, the adsorption of ZnO on H2BDC resulted in examining binding energies, the charge transfer, density of ...
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To investigate the adsorption property of H2 and CO2 on the organic ligand of C-MOF-5 (H2BDC) and T-MOF-5 (ZnO-doped H2BDC (ZnO-H2BDC)), Density functional theory (DFT) method was performed. First, the adsorption of ZnO on H2BDC resulted in examining binding energies, the charge transfer, density of states, dipole moments and adsorption geometries were investigated. The binding properties have been calculated and investigated theoretically for ZnO-doped H2BDC in terms of binding energies, band structures, Mulliken charges, and density of states (DOSs). According to obtained results, the H2BDC was strongly doped with ZnO. H2 and CO2 adsorption capacities for ZnO-doped H2BDC are significantly enhanced while there are low adsorption capacities for H2BDC. According to results, at least in the organic ligand of the MOF-5, the highest and lowest adsorption of CO2 (or H2) is attributed to the T-MOF-5 and C-MOF-5 respectively. Our calculations reveal that ZnO-doped H2BDC system (T-MOF-5) has much higher adsorption energy and higher net charge transfer value than pristine H2BDC (C-MOF-5). Also by changing in structure from cubic to tetragonal, the main site for H2 and CO2 adsorption was changed.
Asadollah Mohammadi; Ali Aliakbarzadeh Karimi
Abstract
This study describes the adsorption and photocatalytic removal of methylene blue (MB) from aqueous solution by surface-modified TiO2 nanoparticles under ultraviolet irradiation in a batch system. The 5-sulfosalicylic acid grafted TiO2 (5-SA-TiO2) as a photocatalyst was characterized by means of ...
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This study describes the adsorption and photocatalytic removal of methylene blue (MB) from aqueous solution by surface-modified TiO2 nanoparticles under ultraviolet irradiation in a batch system. The 5-sulfosalicylic acid grafted TiO2 (5-SA-TiO2) as a photocatalyst was characterized by means of XRD, FTIR and SEM techniques. The surface of TiO2 nanoparticles was modified by 5-sulfosalicylic acid (5-SA) to increase performance by altering surface properties. Notably, in contrast with the adsorption process, the remarkable removal enhancement of MB dye was observed by photocatalytic degradation process from aqueous solution. The adsorption and photocatalytic degradation kinetics of MB using 5-SA-TiO2 nanoparticles have also been investigated. The results show that the photocatalytic degradation was good fit with the pseudo-first-order kinetic model (R2 > 0.99). The adsorption isotherm of MB onto modified TiO2 nanoparticles fitted into the Temkin equation. In addition, thermodynamic studies indicate the spontaneous behavior of adsorption and photocatalytic degradation processes.
Zahra Sarteep; Azadeh Ebrahimian Pirbazari; Mohammad Ali Aroon
Abstract
Hydrothermally synthesized TiO2 nanoparticles containing different amounts of silver were characterized by X-Ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy equipped with energy dispersive X-ray microanalysis (SEM/EDX) techniques. XRD results showed prepared ...
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Hydrothermally synthesized TiO2 nanoparticles containing different amounts of silver were characterized by X-Ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy equipped with energy dispersive X-ray microanalysis (SEM/EDX) techniques. XRD results showed prepared samples include 100% anatase phase. The presence of silver in TiO2 nanoparticle network was established by XRD, SEM/EDX and FT-IR techniques. The photocatalytic performance of the prepared catalysts was tested for the degradation of 2,4-dichlorophenol (2,4-DCP) under visible light.. The experiments demonstrated that 2,4-DCP was effectively degraded in the presence of Ag/TiO2 samples. It was confirmed that the presence of Ag on TiO2 catalysts could enhance the photocatalytic degradation of 2,4-DCP in aqueous suspension. It was found that an optimal dosage of 1.68 wt% Ag in TiO2 achieved the fastest 2,4-DCP degradation (95% after 180 min irradiation) under the experimental conditions. On the basis of various characterizations of the photocatalysts, the reactions involved to explain the photocatalytic activity enhancement due to Ag doping include a better separation of photogenerated charge carriers. GC-MS analysis showed the major intermediates of 2,4-DCP degradation are simple acids like oxalic acid, acetic acid, etc. as the final products.
Seyed Hassan Sharifi; Hassan Shoja
Abstract
The purpose of this investigation is to study the influence of Spruce sawdust (SD) coated by magnesium oxide (MgO) nanoparticles in the removing of methylene blue (MB) from an aqueous solution which is in a batch system. The adsorbent was characterized by FTIR, FE-SEM, BET and XRD analysis. The high ...
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The purpose of this investigation is to study the influence of Spruce sawdust (SD) coated by magnesium oxide (MgO) nanoparticles in the removing of methylene blue (MB) from an aqueous solution which is in a batch system. The adsorbent was characterized by FTIR, FE-SEM, BET and XRD analysis. The high adsorption potential of SD-MgO nano-biocomposite was revealed by these findings, therefore, it is usable for dye-containing wastewater treatment. By investigating the impact of particular conditions like MB concentrations, the dose of adsorbent and pH, it became possible to confirm the effectiveness of the process. The OOP (which stands for Optimum Operating Parameters) were evaluated by RSM (which stands for Response Surface Methodology) which is based on BBD (Box-Behnken design) and is used for removing MB dye. The adsorbent dosage is the highest effective degree of the individual factor on MB removal. Maximum removal of MB dye was detected at pH 11 with 3.50 g L-1 adsorbent dosage. The surface area of 0.873 m2 g-1 and mesoporous adsorbent prepared gave good adsorption capacity of 26.657 mg g-1 for MB. Furthermore, in order to predict the empirical variables’ significance, the variances’ analysis (ANOVA) was used. The predicated removal efficiency which is proved to be the potency of the process and its effectiveness was found to be 94.05%. Different equilibrium and kinetic models were utilized to the experimental data. Both Pseudo-second order kinetic model and Freundlich adsorption isotherm showed the better fitness to the experimental data.
Susan Samadi; Mostafa Mirzaie Shalmani; Amirabbas Zakaria
Abstract
The zeolite N.P./PEG/GO composite was synthesized by hydrothermal assisted sol-gel method to be used as Pb2+ and Cd2+ ions nano-adsorbent from the agricultural water. The FT-IR spectrum confirmed the expected microstructure of synthesized adsorbent. The SEM revealed the formation of zeolite nanoparticles ...
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The zeolite N.P./PEG/GO composite was synthesized by hydrothermal assisted sol-gel method to be used as Pb2+ and Cd2+ ions nano-adsorbent from the agricultural water. The FT-IR spectrum confirmed the expected microstructure of synthesized adsorbent. The SEM revealed the formation of zeolite nanoparticles and the layer structure of graphene. The existence of expected elements and crystalline structures were confirmed by EDS and XRD analysis, respectively. The pH, contact time, temperature and adsorption amount was optimized in the removal process of lead (II) and cadmium ions. The results were 6, 20 min, 25 oC and 0.005g for Pb2+ and 4, 20 min, 25 oC and 0.005g for Cd2+ respectively. Adsorption capacity of Lead (II) and cadmium ions were 49.6 and 50.2 mg.g-1 of adsorbent, respectively. Interference ions don’t show any considerable effects on the efficiency of adsorption for both ions. The equilibrium data can well be fixed using both Langmuier and Freundlich equations.
Yousef Vazifeshenas; Reza Yousefi; Esmaeil Rahimi
Abstract
Power plants are of great influential industries to the environment which could be studied in many ways. Since the optimum equipment would consume less fuel, the issue is mainly interested to those who are concerned about the environmental effects. Amongst various methods, utilizing twisted tapes inserts ...
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Power plants are of great influential industries to the environment which could be studied in many ways. Since the optimum equipment would consume less fuel, the issue is mainly interested to those who are concerned about the environmental effects. Amongst various methods, utilizing twisted tapes inserts which are of passive type is interested in this effort. Although numerous types of tapes are widely utilized, modifying the tape configuration according to the flow specification is still interested. So here the center-cleared and perforated tapes are considered to be compared against the typical type. The 3D numerical simulation of finite volume method was applied to cover the flow field of the problem. The RNG k-ε turbulence model was responsible for the turbulent behavior of the flow and its circular trend. In order to develop the performance of the optimum tape performance, AL2O3 nanoparticles of different volume concentrations were added to the base fluid. The results showed that the Nu number was enhanced about 22% by using merely the center-cleared 14cm, while the friction factor was increased about 13%. To develop these amounts for the optimum configuration, adding nanoparticles of 0.1% concentration put and increment of 26% for heat transfer.
Kamal Alizadeh; Ziba Yaghouby; Azim Shams
Abstract
The electrochemical property of a recently synthesized ligand, 3-((3-mercaptophenyl) aminomethyl)benzene-1,2-diol has been investigated with construction of a modified carbon paste electrode to find out of mercury ions in real samples. To modify the electrode, paraffin oil and multi-walled carbon nanotubes ...
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The electrochemical property of a recently synthesized ligand, 3-((3-mercaptophenyl) aminomethyl)benzene-1,2-diol has been investigated with construction of a modified carbon paste electrode to find out of mercury ions in real samples. To modify the electrode, paraffin oil and multi-walled carbon nanotubes (MWCNT) were used as binder and modifier respectively. Under the optimized conditions, the electrode exhibits a Nernstian slope of 30.0±0.2 mV per decade for mercury(II) ions over a broad concentration range 1×10-7 to 1×10-1M with a R2 value of 0.996 at pH 4.5 in a 5 sec response time. The detection limit of the method for Hg2+ was 2.3×10−8 mol l−1. The influence of several potentially interfering ions such as K+, Ag+, Cd2+, Ni2+, Ca2+, Cr3+, Pb2+, Cu2+, Co2+, Mg2+, Fe2+, Al3+, La3+ and Fe3+ on the determination of Hg2+ was studied and no significant interference was observed. The proposed modified carbon paste electrode was successfully applied to the determination of mercury ions in real water samples.
Taher Yousefi; Mohammad Abas Mohsen; Hamid Reza Mahmudian; Meisam Torab-Mostaeidi; Mohammad Ali Moosavian; Hassan Aghayan
Abstract
In the current work, the natural zeolite was modified with cobalt hexacyanoferrate and employed for adsorbent of Pb(II) ions from aqueous solution. The modification was approved by XRD and FTIR techniques. The Pb(II) adsorption capacity enhanced by 1.8 times from 60 mg/g (natural zeolite) to 100 mg/g ...
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In the current work, the natural zeolite was modified with cobalt hexacyanoferrate and employed for adsorbent of Pb(II) ions from aqueous solution. The modification was approved by XRD and FTIR techniques. The Pb(II) adsorption capacity enhanced by 1.8 times from 60 mg/g (natural zeolite) to 100 mg/g (modified zeolite) at optimal conditions. Factors such as time, pH, temperature, adsorbent dosage and initial concentration were investigated to optimize the adsorption condition. A fast sorption was observed in the initial contact time and equilibrium was achieved in less than 120 min. The optimum pH for lead removal was between 3 and 6. The adsorption capacity was increased and reached the maximum of 90 % at 2 g/L adsorbent dosage. Also, the adsorption increased as the concentration increased up to 500 mg/L and the sorption became constant at higher concentration. It was found that the double-exponential model describes the lead sorption kinetics and the Langmuir–model describe the isotherms.
Vahideh Abdollahi; Habib Razmi
Abstract
In this study graphene quantum dots/eggshell membrane nanocomposite (GQDS/ESM) is prepared and used as an efficient solid-phase extraction (SPE) sorbent for preconcentration of organophosphorus pesticides (OPPs) from aqueous solutions. The retained analytes on the sorbent are stripped by acetonitrile ...
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In this study graphene quantum dots/eggshell membrane nanocomposite (GQDS/ESM) is prepared and used as an efficient solid-phase extraction (SPE) sorbent for preconcentration of organophosphorus pesticides (OPPs) from aqueous solutions. The retained analytes on the sorbent are stripped by acetonitrile and subsequently are determined by high-performance liquid chromatography. Various parameters affecting the extraction efficiency of OPPs on the GQDS/ESM, such as solution pH, amount of nano-sorbent, sample loading flow rate, elution conditions and sample volume are investigated. The results demonstrated that the proposed method has a wide dynamic linear range (0.05–100 ng mL-1), good linearity (R2>0.997) and low detection limits (0.006-0.32 ng mL-1). High enrichment factors are achieved ranging from 110 to 140. In the optimum experimental conditions, the established method is successfully applied for the determination of OPPs in spiked water samples (well, tap, shaft and canal) and apple juice. Satisfactory recovery results show that the sample matrices under consideration do not significantly affect the extraction process.
Atiyeh Yazdani; Mohammad Sayadi; ava Heidari
Abstract
Worldwide studies on contamination levels of anti-inflammatory drugs such as ibuprofen (IBF) show that their concentration in water bodies is increasing. Graphene oxide/palladium nanoparticle (Pd NPs-GO) was synthesized via a simple solvothermal method. The characteristics of the as-prepared samples ...
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Worldwide studies on contamination levels of anti-inflammatory drugs such as ibuprofen (IBF) show that their concentration in water bodies is increasing. Graphene oxide/palladium nanoparticle (Pd NPs-GO) was synthesized via a simple solvothermal method. The characteristics of the as-prepared samples were examined using X-ray fluorescence, scanning electron microscopy, and Fourier transforms infrared spectroscopy. The performance of Pd NPs-GO nanocomposite as a sonocatalyst was evaluated for the degradation of IBF under ultrasonic irradiation (35 kHz), and compared with graphene (GO) and palladium nanoparticle (Pd NPs). Some influencing parameters such as IBF initial concentration, pH, catalyst dosage, and irradiation time were investigated. The findings showed that Pd NPs-GO nanocomposite exhibited higher sonocatalyst activity for IBF than other catalysts. A higher ibuprofen degradation efficiency was observed in lower pH (3), lower initial concentration (30 mg/L), higher catalyst dosage (2 g/L), and higher ultrasonic irradiation time (50 min). The kinetics of the degradation of IBF followed pseudo-first-order reaction kinetics.
Ali Bahari; Hussein Salmani
Abstract
In the present work, Graphene Oxide (GO) nano particles with 0.1, 0.2, 0.4 and 0.8 weight percentages (wt.% ), synthesized by Hummer method entered into the Di-Calcium Silicate (C2S) matrix (synthesized with using Pechini method and their nano structural and mechanical characteristics studied by XRD ...
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In the present work, Graphene Oxide (GO) nano particles with 0.1, 0.2, 0.4 and 0.8 weight percentages (wt.% ), synthesized by Hummer method entered into the Di-Calcium Silicate (C2S) matrix (synthesized with using Pechini method and their nano structural and mechanical characteristics studied by XRD (X-ray diffraction), FTIR (Fourier transform infrared), GPS 132 A, 4- probe techniques and emission factor analyses. To study and examine GO-C2S nano composites as an environmentally- friendly Material for sustainable Development of Cement Structure 4- capacitor form, with Metal (Al) /GO-C2S composite/ Si substrate are fabricated. The quality factor and dissipation factor were measured by GPS 132 A tool. The obtained results show that sample with 0.4% wt. of GO nano particles has 0.625 fraction emission factor and higher quality factor (32.4), measured at two frequencies of 120 KHz and 1 KHz. Therefore C2S/ GO nano composite with 0.4 wt.% GONs can be therefore introduced as a good additive to reduced emission factor for production of cement and dissipation factor.
Amirali Abbasi; Jaber Jahanbin Sardroodi; Alireza Rastkar Ebrahimzadeh
Abstract
First-principles calculations within density functional theory (DFT) have been performed to investigate the interactions of NO2 molecules with TiO2/Gold nanocomposites in order to completely exploit the adsorption properties of these nanostructures. Given the need to further comprehend the behavior of ...
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First-principles calculations within density functional theory (DFT) have been performed to investigate the interactions of NO2 molecules with TiO2/Gold nanocomposites in order to completely exploit the adsorption properties of these nanostructures. Given the need to further comprehend the behavior of the NO2 molecules positioned between the TiO2 nanoparticle and Au monolayer, we have geometrically optimized the complex systems consisting of the NO2 molecule oriented at appropriate positions between the nanoparticle and Au monolayer. The structural properties such as bond lengths, bond angles, adsorption energies and Mulliken population analysis and the electronic properties including the density of states and molecular orbitals have been also analyzed in detail. The results indicate that the interaction between NO2 and undoped TiO2-N/Gold nanocomposites is stronger than that between gas molecules and N-doped TiO2/Gold nanocomposites, which reveals that the pristine nanocomposite can react with NO2 molecule more efficiently. Therefore, the obtained results also suggest a theoretical basis for the potential applications of TiO2/Gold nanocomposites in gas sensing, which could help in the developing of novel TiO2 based advanced sensor devices.
Mustafa Nadhim Owaid; Sajid Salahuddin Saleem Al-Saeedi; Idham Ali Abed
Abstract
Twelve extracts belong to four species of edible oyster mushrooms were screened for their chemical value (viz. proteins, carbohydrates and phenols were assessed) and their capability to biosynthesize silver nanoparticles (AgNPs). In limitative conditions, dark incubation and temperature 25 °C, three ...
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Twelve extracts belong to four species of edible oyster mushrooms were screened for their chemical value (viz. proteins, carbohydrates and phenols were assessed) and their capability to biosynthesize silver nanoparticles (AgNPs). In limitative conditions, dark incubation and temperature 25 °C, three modes of extracts preparation were developed. Properties of silver nanoparticles creation from extracts solution with 1 mM AgNO3 were investigated by color and UV-Visible spectroscopy to confirm silver nanoparticles formation. The bright yellow oyster mushroom (Pleurotus cornucopiae var. citrinopileatus) was finding as a potential candidate for the synthesis of AgNPs. Brown color of aqueous solution was given indication for AgNPs formation. Results showed that AgNPs absorption band was located at a peak of 440 nm for P. cornucopiae var. citrinopileatus. Although others P. ostreatus (grey & white) and P. salmoneostramineus (pink) were not form AgNPs due to no change in color of extracts with Ag ions when incubated under the same conditions, which indicative for no silver nanoparticles synthesis. Thus, AgNPs formation depended on species of oyster mushroom, method of extracting, concentration of extract and the conditions of incubation (of light and temp.), but no on content of proteins, carbohydrates and phenol in crude extract leastwise in this study