Farzaneh Arsiya; Mohammad Sayadi; Sara Sobhani
Abstract
The presence of Arsenic in drinking water is the greatest threat to health effects especially in water. The purpose of this study is application of green palladium nanoparticles for removal of trivalent Arsenic from aqueous solutions and also the impact of some factors such as retention time, pH, concentration ...
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The presence of Arsenic in drinking water is the greatest threat to health effects especially in water. The purpose of this study is application of green palladium nanoparticles for removal of trivalent Arsenic from aqueous solutions and also the impact of some factors such as retention time, pH, concentration of palladium nanoparticles and Arsenic concentrations was studied. The values for Arsenic removal from aqueous solutions were measured by furnace atomic adsorption spectrometry (Conter AA700). In the study, Langmuir and Freundlich isotherm models and pseudo-second order kinetic model were studied. The results of optimization is shown that 0.5 g of nanoparticles can removed %99.8 of Arsenic with initial concentration of 0.5 g/l, in 5 minutes at pH=4. Langmuir model, Freundlich model (R2=0.94) and pseudo-second order kinetic model (R2=0.99) shown high correlation for removing of Arsenic from aqueous solutions. It was found, palladium nanoparticles can be used as an efficient method to remove Arsenic from aqueous solutions in a short time.
Atefeh Tizchang; Yoones Jafarzadeh; Reza Yegani; Elham Shokri
Abstract
In this study, polysulfone (PSf) nanocomposite membranes embedded with functionalized nanodiamond (ND) were prepared via Non-Solvent Induced Phase Separation (NIPS) method. ND nanoparticles were silanized by using the esterification reaction of hydrolyzed vinyltrimethoxysilane (VTS) in alcoholic solution ...
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In this study, polysulfone (PSf) nanocomposite membranes embedded with functionalized nanodiamond (ND) were prepared via Non-Solvent Induced Phase Separation (NIPS) method. ND nanoparticles were silanized by using the esterification reaction of hydrolyzed vinyltrimethoxysilane (VTS) in alcoholic solution in order to enhance the compatibility between ND and PSf. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed that ND nanoparticles were successfully functionalized by silane groups. Nanocomposite membranes were then prepared with different percentages of silanized NDs (SNDs). The membranes were characterized using a set of analyses and the results showed that the addition of SNDs up to 1.0 wt.% resulted in an increase in hydrophilicity, water content, porosity and water flux of membranes. Moreover, Scanning Electron Microscopy (SEM) images indicated that the membrane with 1.0 wt. % nanoparticles had more pores on the membrane surface with smaller average pore size in comparison to other membranes. Antifouling properties of the membrane was also investigated in filtration of humic acid solution and the results showed that reversible fouling and flux recovery of membranes increased at the presence of SNDs.
Saied Saeed Hosseiny Davarani; Hamid Reza Moazami; Taher Yousefi; Masoud Abrari
Abstract
A flexible route for the electrosynthesis of visible light active CdxZn1-xO nanostructures has been proposed. Various nanostructures were prepared by anodic dissolution in 0.1M Me4NCl by using an applied potential of 15V for 30min. The prepared nanostructures were characterized by diffuse reflectance ...
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A flexible route for the electrosynthesis of visible light active CdxZn1-xO nanostructures has been proposed. Various nanostructures were prepared by anodic dissolution in 0.1M Me4NCl by using an applied potential of 15V for 30min. The prepared nanostructures were characterized by diffuse reflectance UV-Vis spectroscopy (DRS), Fourier transforms infrared spectrometry (FT-IR), X-Ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the crystalline structure, morphology, and energy band gap of the products can be finely adjusted only by varying the duty cycle of the anodeswitching. The visible light activity of the obtained nanostructures was investigated using methyl orange as a model organic pollutant. It was found that the proposed method can be used to obtain very effective CdxZn1-xO photocatalysts by fine tuning of the morphology and energy band gap. The prepared photocatalyst retained 80% of its original activity after 5 replicated uses.
Marjan Tanzifi; Marzieh Kolbadi nezhad; Kianoush Karimipour
Abstract
The present work seeks to investigate the ability of polypyrrole/titanium dioxide nanocomposite to adsorb cadmium ions from aqueous solution. The impact of various experimental conditions, including solution pH, adsorbent dosage, adsorption time and initial concentration on the uptake of cadmium were ...
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The present work seeks to investigate the ability of polypyrrole/titanium dioxide nanocomposite to adsorb cadmium ions from aqueous solution. The impact of various experimental conditions, including solution pH, adsorbent dosage, adsorption time and initial concentration on the uptake of cadmium were studied. The adsorption kinetic was studied with the first-order, second-order, pseudo-first-order, pseudo-second-order and Morris–Weber models. The results revealed that adsorption process is controlled by pseudo-second-order model which illustrated that the adsorption process of cadmium is chemisorption-controlled. The adsorption capacity obtained from this model is 20.49 mg/g which close to the experimental value. The study yielded the result that when the initial concentration of the solution changed from 20 mg/l to 120 mg/l, the adsorption capacity increased from 0.99 to 24.52 mg/g. Further, Langmuir, Freundlich and Temkin isotherm models were applied to investigate the adsorption isotherm. Based on the results of the adsorption isotherm, Freundlich isotherm proved to be the best fit with the experimental data. Also, the morphology, chemical structure and thermal stability of adsorbent were studied by using SEM, EDX, FTIR, and TGA.
Ali Akbar Safari Sinegani; Omid Noroozi
Abstract
Survival of enteropathogenic bacteria in soil is a key factor to control waterborne diseases. The significance of zeolite nanoparticles in comparison with natural size particles on the survival of Escherichia coli in soil was studied in sterile and unsterile conditions. The experimental mixtures prepared ...
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Survival of enteropathogenic bacteria in soil is a key factor to control waterborne diseases. The significance of zeolite nanoparticles in comparison with natural size particles on the survival of Escherichia coli in soil was studied in sterile and unsterile conditions. The experimental mixtures prepared by adding zeolite and nanozeolite at levels of 0, 5, 15% w/w to a loam textural soil to obtain 100 gr mixtures. Mixtures inoculated by a nalidixic acid resistance Escherichia coli (E.coli NAR) at a rate of 106 cells gr-1 soil. Results showed that in the unsterile soils, adding 5% zeolite had no significant effect on the survival of bacteria in soil and 15% nanozeolite reduced bacteria survival in soil especially at initial days of inoculation (about 3 log-unit). While adding 15% zeolite and 5% nanozeolite had a significantly positive effect on bacteria's time need to reach the detection limit (td). Sterilization of soil mixtures significantly enhanced bacteria survival in all treatments. The highest value of td obtained in sterile soil amended with 15% zeolite (46 days). In sterile mixtures adding nanozeolite caused an increasing in bacteria population at initial days after inoculation (about 1-1.5 log-units). Decreasing in the size of natural zeolite particles to nanoscale had a negative effect on survival of the studied bacterium in unsterile mixtures and E.coli NAR survived more in zeolite amended mixtures. While this negative effect was not observed in sterile soil. These results clearly showed that competition is the main factor that controls enteropathogenic bacteria's survival in soil.
Mahzad Mirzaei; Reza Khanbabaie; Mohsen Jahanshahi; Ghasem Najafpour Darzi
Abstract
Recently, safety concerns over the handling of nanomaterials have become an important issue. The aim of the present study was to optimize the key parameters in the hydrothermal synthesis of CuInS2 quantum dots (QDs) as a non-toxic alternative to the cadmium-based QDs, that historically had dominated ...
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Recently, safety concerns over the handling of nanomaterials have become an important issue. The aim of the present study was to optimize the key parameters in the hydrothermal synthesis of CuInS2 quantum dots (QDs) as a non-toxic alternative to the cadmium-based QDs, that historically had dominated the literature. Response surface methodology (RSM) in combination with D-optimal design was applied to optimize the synthesis and evaluate the PL intensity as the response which described by a reduced quadratic equation. The relationship between the PL intensity and independent variables (ligand/precursor, reaction time, reaction temperature, pH, and precursors ratio) was investigated using reduced quadratic polynomial equations. The produced QDs in the optimum condition were analyzed by UV-Vis, FE-SEM, and FTIR. The results showed that the nanoparticles have a high PL intensity and a red shift in both emission and absorbtion spectra which is a splendid point for their applications specially in bioimaging. The interaction between variables was not significant and the temperature was the most effective variable of PL intensity. A good agreement between predicted model and experimental data confirmed the correlated model.
Samad Sabbaghi; Fateme Doraghi
Abstract
In this study, considering the importance of protecting the environment and preventing the pollution caused by industrial plants, a nanocomposite each component thereof is capable of removing the desired combination to solve this problem has been produced. To achieve this goal, ZnO/SnO2nanocomposite ...
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In this study, considering the importance of protecting the environment and preventing the pollution caused by industrial plants, a nanocomposite each component thereof is capable of removing the desired combination to solve this problem has been produced. To achieve this goal, ZnO/SnO2nanocomposite was synthesized using the co-precipitation method. The characterization of this nanocomposite was conducted by DLS, XRD, FTIR and SEM. The nanocomposite size was about 15nm. Several parameters such as the initial concentration of the wastewater, as well as the amount of catalyst and time were investigated. The reduction of the particle size due to an increase in the surface area of the nanocomposite increased the amount of decolorization. For all the performed experiments, the dye removal rate was 100% and the difference was to do with the time of the complete removal of methylene blue. A decrease in the concentration of methylene blue in the range of the tested concentrations reduced the decolorization, and by increasing the amount of nanocomposite in the range of the tested values, a decline in decolorization was observed.
Leila Mahdavian
Abstract
The CO and CO2 effects are global warming, acid rain, limit visibility, decreases UV radiation; yellow/black color over cities and so on. In this study, convention of CO2 and H2O to CH4 and O2 near TiN- nanotube with Cu-nanoparticle calculated by Density Functional Theory (DFT) methods. We have studied ...
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The CO and CO2 effects are global warming, acid rain, limit visibility, decreases UV radiation; yellow/black color over cities and so on. In this study, convention of CO2 and H2O to CH4 and O2 near TiN- nanotube with Cu-nanoparticle calculated by Density Functional Theory (DFT) methods. We have studied the structural, total energy, thermodynamic properties of these systems at room temperature. All the geometry optimization structures were carried out using GAMESS program package under Linux. DFT optimized their intermediates and transient states. The results have shown a sensitivity enhancement in resistance and capacitance when CO2 and H2O are converted to CH4 and O2. TiN-nanotube used photo-catalytic reactivity for the reduction of CO2 with H2O to form CH4 and O2 at 298K. The calculations are done in state them between of three TiN-nanotubes near Cu-nanoparticle.The calculation shown which heat reaction formation (∆H) is endothermic for this reaction. This reaction needs to sun, photo active or other energy in the presence of visible light for doing.
Mohammad Reza Jalali Sarvestani; Roya Ahmadi
Abstract
In this study, the impact of doping graphene with silicon and germanium on the adsorption of Ag+ was evaluated by density functional theory. At the outset, the structures of silver, adsorbents and their derived products at ten different configurations were optimized geometrically. Then, IR and frontier ...
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In this study, the impact of doping graphene with silicon and germanium on the adsorption of Ag+ was evaluated by density functional theory. At the outset, the structures of silver, adsorbents and their derived products at ten different configurations were optimized geometrically. Then, IR and frontier molecular orbital calculations were implemented on them and some important parameters such as adsorption energy, Gibbs free energy changes, enthalpy variations, the thermodynamic equilibrium constant, specific heat capacity, chemical hardness, energy gap and electrophilicity were obtained and inspected. The achieved results indicate that by doping graphene with silicon and germanium the adsorption process has become more spontaneous, exothermic and experimentally feasible. The influence of temperature on the adsorption procedure was also checked out and the results indicate that 298.15 K is the optimum temperature for the desired process at all of the evaluated configurations. The HOMO-LUMO related parameters reveal that the pure and also doped nano-adsorbents are not appropriate sensing material in the construction of conductometric sensors but they can act as an eminent neutral ion carrier in the development of a potentiometric ion selective electrode for determination of silver (I) cations.
Vida Alizadeh; Bahram Golestani Eimani; Fariba Amjady
Abstract
Background and objectives: Drug resistance in bacteria is one of the important problems in the antibacterial field. Therefore, new drugs and therapeutic approaches are required to eliminate bacteria using different and novel mechanisms. Among these, the silver nanoparticles have been proposed as a substance ...
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Background and objectives: Drug resistance in bacteria is one of the important problems in the antibacterial field. Therefore, new drugs and therapeutic approaches are required to eliminate bacteria using different and novel mechanisms. Among these, the silver nanoparticles have been proposed as a substance with antibacterial properties against gram-positive and gram-negative bacteria. The present study aimed to investigate the effects of silver nanoparticles with a size of less than 20 nm on the genome of Staphylococcus aureus (S. aureus) as a model for gram-positive bacteria.Material and methods: For this purpose, the bacteria were treated at concentrations of 100 and 150 µg/ml nanoparticles and antimicrobial properties of the nanoparticles were investigated in intervals of 2, 4 and 24 hours, then DNA was extracted. RAPD molecular marker was used to investigate the effects of nanoparticles on the genome. In addition, the results of electrophoresis for polymerase chain reaction (PCR) products on agarose gel were analyzed.Results: The present findings demonstrated that silver nanoparticles not only have an inhibitory effect on bacteria but also affect the genomic DNA sequence of this bacterium and change it in different sites.Conclusion: The nanoparticles are antibacterial compounds and can be an appropriate alternative to antibiotics.
Maher Abed el Aziz; Aziza Ashour; Hewaida Madbouly; Al Sadek Melad; Khald El Kerikshi
Abstract
Green preparation of heavy metal saponin complexes has been successfully optimized by direct combination between crude extract of Olea Europaea and Citrus Aurantium with divalent heavy metals, Pb2+ and Cd2+. The main operating factors affecting preparation process were investigated and evaluated in terms ...
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Green preparation of heavy metal saponin complexes has been successfully optimized by direct combination between crude extract of Olea Europaea and Citrus Aurantium with divalent heavy metals, Pb2+ and Cd2+. The main operating factors affecting preparation process were investigated and evaluated in terms of setting time, heavy metal ion concentration, crude extract concentration, and pH value of the medium. Saponin complexes had been prepared using the optimum concentrations of heavy metal ions (120 ppm) and optimum concentration of crude extract (600 ppm) in the slightly alkaline medium. The presence of saponin in plants was confirmed by chemical tests and UV/Vis analysis. Amount of prepared saponine complexes has the order: (Pb/Olive) > (Cd/Olive) > (Pb/Citrus) > (Cd/Citrus). In this process, saponins was isolated and heavy metals were eliminated by a simple, faster and without a huge amount of solvents. The process itself seems to be green isolation of saponins from plants, green removal of heavy metal from aqueous waste streams or green preparation of heavy metal saponin complexes. The process exhibits several advantages and hence benefits, among of them are shorter setting time, higher volume reduction factor and no chemical or solvents used. Direct combination between heavy metals solution and plant extract solution to prepare saponin complex could be considered three in one process. During preparation of the complex, saponin isolated or extracted by heavy metals and the heavy metal eliminated or removed by saponin solution.
Eduarda Regina Carvalho; Wilson Tadeu Lopes da Silva
Abstract
A sensor system, adapted to evaluate tap water, was fabricated and tested. Interdigitated gold-coated microelectrodes were covered with various conducting polymers, single or mixed, under several different conditions. Polymer films were laid down by a self-assembly technique and their impedance ...
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A sensor system, adapted to evaluate tap water, was fabricated and tested. Interdigitated gold-coated microelectrodes were covered with various conducting polymers, single or mixed, under several different conditions. Polymer films were laid down by a self-assembly technique and their impedance was analyzed over a range of frequencies from 1Hz to 1MHz. Samples collected from different localities at São Paulo state (Brazil) were used. The results of sensorial system analyzed by Principal Component Analysis had allowed completing discrimination of tap water samples. Good discrimination between the sensors was observed when there was obtained a PCA with different samples, obtaining the total variance (PC1 = 62.03%; PC2 = 37.97%) of the observations. The sensorial system based in global selectivity using interdigitated electrode and nanostruturated conducting polymers allowed a statistical discrimination of sample waters of different locations. The future expectations are the upgrading of the system and implementation of a monitoring of tap water systems based nanostructured sensors.
Azam Gholami; Mahmood Hajiani; Mohammad Hossein Sayadi Anari
Abstract
Contaminants of emerging concern or simply emerging contaminants have been considered as a critical environmental issue in recent decades. These compounds have not routinely controlled and monitored; therefore they have posed risk to health of human and environment. Drugs are considered as one of the ...
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Contaminants of emerging concern or simply emerging contaminants have been considered as a critical environmental issue in recent decades. These compounds have not routinely controlled and monitored; therefore they have posed risk to health of human and environment. Drugs are considered as one of the most important emerging pollutants. They introduce to environment form different sources such urine, human excretion, livestock, poultry, pharmaceutical, and hospitals. Although they are in trace levels, they are not biodegradable. They cannot be removed by conventional treatment processes. .. Advanced oxidation processes (AOPs) have been designed to address the deficiency of conventional methods in removal of emerging pollutants. Production of highly reactive hydroxyl radicals is the base of AOPs. These very reactive radicals effectively oxidize emerging pollutants such as drugs. Among different approach of AOPs, photocatalytic degradation has been successfully applied to mitigate the side effects of emerging contaminants. The ability of photocatalytic process in removal of Clindamycin hydrochloride (CLM) from aqueous solutions in the presence of UV/TiO2 was studied. The effects of various parameters such as adsorption, photolysis, pH, catalyst dosage, initial concentration of antibiotic, and radiation time were investigated in a batch photoreactor. Results showed that photolysis and adsorption had a negligible contribution to the clindamycin removal. The maximum clindamycin removal rate was obtained under optimal conditions, such as pH of 5, 0.5 g/l of TiO2, initial clindamycin concentration of 2 /L. This optimum condition was achieved during 90 minutes.. The CLM photocatalytic degradation kinetics showed that CLM degradation follows the pseudo-first-order kinetics.
Hossein Mohammadifard; Mohammad C. Amiri
Abstract
Heavy metals pollution in the environment is one of the serious problems in the field of water and wastewater management. In this study; calcium carbonate nanoparticles, synthesized by an efficient and novel method, were used as an adsorbent for the removal of lead and iron from aqueous solutions. To ...
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Heavy metals pollution in the environment is one of the serious problems in the field of water and wastewater management. In this study; calcium carbonate nanoparticles, synthesized by an efficient and novel method, were used as an adsorbent for the removal of lead and iron from aqueous solutions. To study the mechanism of adsorption, the kinetic and isotherm models were examined. The adsorption kinetics of process was found to follow a pseudo-second-order equation. The maximum monolayer adsorption capacities of calcium carbonate nanoparticles calculated from Langmuir isotherm were found to be 1210±30 mg/g for Pb(II) and 845±8 mg/g for Fe(II) ions, respectively. The response surface methodology based on three variable Box-Behnken design was utilized to evaluate the effects of temperature (25-65 oC) and initial metal concentration (10-200 mg/L) on the sorption process. The optimum conditions for the removal process using calcium carbonate nanoparticles were found to be 200 mg/L at 25 oC. Experimental data demonstrated that a precipitation transformation mechanism rather than adsorption enhances the removal efficiency.
Saeed Tizro; Hadi Baseri
Abstract
Cobalt is one of the most hazardous heavy metals present in the environment. Magnetic based nanoadsorbents were used for removal of Co(II) ions in this work. The characteristics results of FT-IR, XRD, TGA, and FE-SEM show that applied coatings were modified magnetite nanoparticles efficiently. The results ...
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Cobalt is one of the most hazardous heavy metals present in the environment. Magnetic based nanoadsorbents were used for removal of Co(II) ions in this work. The characteristics results of FT-IR, XRD, TGA, and FE-SEM show that applied coatings were modified magnetite nanoparticles efficiently. The results of TEM indicate that magnetic nanoadsorbents were produced on the nanoscale with average particle sizes of 60±10 nm. Batch experiments were carried out to determine the removal efficiency of the nanoadsorbents. pH, temperature, contact time, adsorbent dose, shaking rate and the initial concentration of analyte were the studied parameters. At optimized conditions of operation parameters, the maximum removal percentage of 92% was obtained by using magnetite-citric acid as an adsorbent. Equilibrium data for Co(II) ions adsorption onto magnetite-citric acid were fitted well by Langmuir isotherm model and the maximum adsorption capacity for Co(II)ions was obtained 43.292 mg/g at 313 K. Also, thermodynamic parameters reveal the spontaneity, feasibility and endothermic nature of the Co(II) ions adsorption process. In addition, the cobalt ions can be desorbed from magnetite-citric acid nanoadsorbent by using nitric acid solution with 95% desorption efficiency and the magnetite-citric acid nanoadsorbent exhibits good recyclability.
Mohammad Rostamizadeh; Soorena Gharibian; Samira Rahimi
Abstract
Pharmaceutical wastewaters have several negative effects on human health. This study reports heterogeneous and ultrasound assisted electro Fenton (HSEF) for efficient degradation of Phenazopyridine (PHP). The high silica zeolite socony mobil–5 (ZSM-5) nanocatalyst is synthesized by hydrothermal ...
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Pharmaceutical wastewaters have several negative effects on human health. This study reports heterogeneous and ultrasound assisted electro Fenton (HSEF) for efficient degradation of Phenazopyridine (PHP). The high silica zeolite socony mobil–5 (ZSM-5) nanocatalyst is synthesized by hydrothermal technique and impregnated with iron species (0.1Fe-ZSM-5). The surface and textural properties of the synthesized nanocatalyst were characterized by X-ray Diffraction (XRD), Transmission electron Microscopy (TEM) and N2 adsorption-desorption techniques. The nanocatalyst includes the high crystallinity (ca. 72.41 %), surface area (ca. 294.40 m2g-1) and uniform dispersion of Fe species. The optimum operating conditions of the HSEF system are pH= 7, applied current of 100 mA, 0.1Fe-ZSM-5 nanocatalyst concentration of 0.2 gL-1 and ultrasonic power of 600 WL-1 which result in the highest PHP removal efficiency. The high performance of the developed nanocatalyst in three consecutive runs confirms the reusability of the nanocatalyst. The results show that the HSEF system has a high capacity for the efficient removal of PHP without requiring long reaction time, high applied current and strict acidic conditions which candidates it for the industrial applications.
Kamal Alizadeh; Esmail Khaledyan; Yagoub Mansourpanah
Abstract
In this study, a selective, fast and novel magnetic mesoporous silica sorbent Fe3O4@MCM-41-NH2, was synthesized, functionalized and has been used for the removal of Pb+2 ions from aqueous solution. The characteristics of the Fe3O4@MCM-41-NH2 sorbent was investigated by XRD, VSM, SEM, TEM, ...
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In this study, a selective, fast and novel magnetic mesoporous silica sorbent Fe3O4@MCM-41-NH2, was synthesized, functionalized and has been used for the removal of Pb+2 ions from aqueous solution. The characteristics of the Fe3O4@MCM-41-NH2 sorbent was investigated by XRD, VSM, SEM, TEM, BET, and FT-IR. The response surface methodology (RSM) based on central composite design (CCD) was utilized for estimating the effects of parameters, namely contact time (min), pH, the quantity of adsorbent (g) and initial concentration of Pb+2. The quadratic model was used as the best model for guessing variables. The results of the analysis of variance for this model were obtained with a high F-value (50.28), very low P-value (<0.0001) and non-significant lack of fit (0.2251). The maximum adsorption capacity was obtained at 46.08 mg/L. Fitting equilibrium data with different isotherm models shows that Freundlich isotherm was the best-fitted model. The pseudo-second-order model was the best model for fitting experimental data.
Mohammad Taghi Kouhiyan Afzal; Ahmad Farrokhian Firouzi; Mehdi Taghavi
Abstract
Zero-valent iron particles at the nanoscale are proposed to be one of the important reductants of Cr(VI), transforming the same into nontoxic Cr(III). In this study zero valent iron nanoparticles(ZVINs) were synthesized and characterized for hexavalent chromium removal from aqueous solutions. Five different ...
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Zero-valent iron particles at the nanoscale are proposed to be one of the important reductants of Cr(VI), transforming the same into nontoxic Cr(III). In this study zero valent iron nanoparticles(ZVINs) were synthesized and characterized for hexavalent chromium removal from aqueous solutions. Five different zero-valent iron nanoparticle types comprising of bare and stabilized ZVINs with poly acrylamide(PAM), polyvinyl pyrrolidone(PVP), polystyrene sulfonate(PSS) and guar gum(GG) were synthesized and employed in this study. The sizes of zero-valent iron nanoparticles were found to be 40, 14, 17, 29 and 34nm, using transmission electron microscopy (TEM), corresponding to bare zero valent iron nanoparticles(ZVINs), poly acrylamide(PAM), guar gum(GG), poly styrene solfunate(PSS) and polyvinyl pyrrolidone(PVP) stabilized zero valent iron nanoparticles (ZVINs) respectively. The trend in the sizes of ZVINs with various stabilizers in the decreasing order was found to be bare ZVIN > PVP-ZVIN >PSS-ZVIN> GG-ZVIN> PAM-ZVIN respectively. Results showed that by increasing hexavalent chromium concentrations from 20 to 100 mg/L, the Cr(VI) efficiency removal decreased significantly. When the ZVINs concentrations increased from 2 to 10 gr/L(0.1 to 0.5g per 50 mL), the Cr(VI) removal efficiency enhanced. The most effective treatments of ZVINs and Cr(VI) for hexavalent chromium removal from solutions were 10 gr/lit (0.5g per 50 mL) and 20 mg/L respectively, so the efficiency of bare and polymer stabilized-ZVINs on Cr(VI) removal from solutions was found to be in the following order: bare ZVINs < PVP-ZVINs <PSS-ZVINs< GG-ZVINs< PAM-ZVINs.
Milad Fonouni; Habib Etemadi; Reza Yegani; Masoumeh Safary Dehnavi; Naeime Jodeiry
Abstract
In this work, KClO3, K2Cr2O7 and KMnO4, dissolved in sulfuric acid, were used to functionalize microporous Polysulfone (PSf) membranes; fabricated by phase inversion method. The optimum concentrations of oxidizing agent and sulfuric acid and membrane immersion times were determined. FTIR results revealed ...
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In this work, KClO3, K2Cr2O7 and KMnO4, dissolved in sulfuric acid, were used to functionalize microporous Polysulfone (PSf) membranes; fabricated by phase inversion method. The optimum concentrations of oxidizing agent and sulfuric acid and membrane immersion times were determined. FTIR results revealed that the absorbance intensities of -OH and C=O peaks as well as the variety of functional groups in the samples treated by KClO3 are remarkably higher than in the samples treated by K2Cr2O7 and KMnO4, respectively. Bovine serum albumin (BSA) filtration experiments revealed that the total fouling ratio (TFR) and irreversible fouling ratio (IFR) decreased from 73.4% for pristine PSf membrane to 52.9%, 49.4% and 60.4% for treated membranes by Set A (K2Cr2O7), Set B (KClO3) and Set C (KMnO4), respectively. Moreover, IFR of membranes decreased from 45.4% for pristine PSf membrane to 29.9%, 22.4% and 36.1% for treated membranes by Set A, Set B and Set C, respectively.
Maryam Ghasemi; Somaye Mashhadi; Javad Azimi-Amin
Abstract
In this study, we have synthesized a new Fe3O4/AC nanocomposite using low cost adsorbent by microwave assisted in situ co-precipitation technique that was used as an effective adsorbent for the removal of methylene blue (MB) using the Taguchi design method as an optimization strategy. The optimum parameters ...
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In this study, we have synthesized a new Fe3O4/AC nanocomposite using low cost adsorbent by microwave assisted in situ co-precipitation technique that was used as an effective adsorbent for the removal of methylene blue (MB) using the Taguchi design method as an optimization strategy. The optimum parameters are pH 7, Fe3O4/AC nanocomposite dose 0.03 g, contact time 30 min, initial concentration of MB 25 mg/L and temperature 298 K. The obtained results of ANOVA show that their percent contribution in descending order is pH (66.81%) > adsorbent dose (25.54%) > temperature (4.83%) > initial MB concentration (1.23%) > contact time (0.32%). The kinetic data were fitted to the pseudo-first-order, pseudo-second-order and intra-particle diffusion models and adsorption of MB dye followed pseudo-second-order kinetic. The obtained values of regression coefficient for Langmuir (0.98), Frendluich (0.93) and Dubinin–Radushkevich (0.94) showed that adsorption process fits to the Langmuir isotherm and the maximum adsorption capacity is 384.6 mg/g. Moreover, the thermodynamics studies suggested the spontaneous nature of adsorption process.
Susan Samadi; Rokhsareh Motallebi; Maryam Nasiri Nasrabadi
Abstract
The efficient application of the photocatalytic activity and superficial adsorption on removing heavy metals from water, two types of sorbents, Nd-TiO2/bentonite and Ce-TiO2/bentonite nanocomposites, were synthesized by sol-gel method. The crystalline nanocomposites were obtained after heat treatment ...
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The efficient application of the photocatalytic activity and superficial adsorption on removing heavy metals from water, two types of sorbents, Nd-TiO2/bentonite and Ce-TiO2/bentonite nanocomposites, were synthesized by sol-gel method. The crystalline nanocomposites were obtained after heat treatment at 500 °C for 3 hours. The results of scanning electron microscopy (SEM) indicates that Nd-TiO2/bentonite and Ce-TiO2/bentonite were produced on a nanoscale. The phase change of both nanocomposite from amorphous to anatase has been investigated by X- ray diffraction. Removal of lead (II) and cadmium (II) were studied through adsorption on these nanocomposites by letting them float in the bulk of sample for a definite time in presence and absence of light. The effective parameters in removal process were studied and optimized. The optimum pH, removal time and sorbent dosage in the absence and presence of light for Pb2+ ion were 7, 0.3 g, 15 min and for Cd2+ ion were 7, 0.4 g, 20 min, respectively. Subsequently, the effect of interfering ions in removal process was investigated at optimum conditions and no evidence of interference was observed. The study showed that reproducibility of method (n=9) is good and suitable. The results further indicated that the removal efficiency of Pb2+ ion with Nd-TiO2/bentonite in the presence of light was more than that in the absence of light. Finally, the equilibrium adsorption data fitted Freundlich and Langmuir adsorption models.
Zahra hassanzadeh Siahpoosh; Majid Soleimani
Abstract
This investigate presents the extraction-preconcentration of Lead, Cadmium, and Nickel ions from water samples using Ghezeljeh montmorillonite nanoclay or “Geleh-Sar-Shoor” (means head-washing clay) as a natural and native new adsorbent in batch single element systems. The Ghezeljeh clay ...
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This investigate presents the extraction-preconcentration of Lead, Cadmium, and Nickel ions from water samples using Ghezeljeh montmorillonite nanoclay or “Geleh-Sar-Shoor” (means head-washing clay) as a natural and native new adsorbent in batch single element systems. The Ghezeljeh clay is categorized by using Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy-Energy Dispersive Spectrometer Operating (SEM-EDS), X-ray Diffractometry (XRD), X-ray Fluorescence (XRF), Cation Exchange Capacity (CEC) measurements, Surface property valuation (SBET) by the BET method from nitrogen adsorption isotherms and Zeta potential. According to BET theory, the specific surface area of Ghezeljeh nanoclay was computed as 19.8 m2 g-1 whereas the cation exchange capacity was determined as 150 meq (100 g-1). The results of XRD, FT-IR, XRF, zeta potential, BET surface area and CEC of the Ghezeljeh clay confirm that montmorillonite is the dominant mineral phase. Based on SEM images of clay, it can be seen that the distance between the plates is nm level. For all three ions, the limit of detection, the limit of quantification, dynamic linear range, preconcentration factor, and the adsorption capacity were obtained. The result of several interfering ions was considered. The Ghezeljeh nanoclay as a new adsorbent and experimental method were effectively used for the extraction of heavy metals (Lead, Cadmium, and Nickel) in a variety of real water samples.
Shahryar Jafarinejad; Mohammad Faraji; Zohreh Norouz; Javad Mokhtari-Aliabad
Abstract
Even at low levels, heavy metals are toxic and can damage living things. They do not break down or decompose and tend to build up in plants, animals, and people causing health concerns. Magnetic nanoparticles (MNPs) can be considered as potential adsorbents for the removal of cadmium (Cd2+) from aqueous ...
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Even at low levels, heavy metals are toxic and can damage living things. They do not break down or decompose and tend to build up in plants, animals, and people causing health concerns. Magnetic nanoparticles (MNPs) can be considered as potential adsorbents for the removal of cadmium (Cd2+) from aqueous solutions because of their high surface area and the combined effect of adsorption and separation under external magnetic fields. In this study, a novel sulfur-modified magnetic nanoparticle was applied as an adsorbent for the removal of Cd2+ ions from aqueous solutions. The adsorbent was characterized by scanning electron microscopy (SEM), Fourier transform-infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). The effects of pH, contact time, and initial concentration of Cd2+ on the removal efficiency of it were investigated in batch adsorption experiments. The equilibrium data fitted the Langmuir isotherm model better than the Freundlich isotherm model, and they were well explained in terms of pseudo-second-order kinetics. The maximum monolayer capacity qm and KL the Langmuir constant were calculated from the Langmuir as 5.1867 mg/g and 0.1562 L/mg, respectively.
Mohammad Ghorbanpour; Atabak Feizi
Abstract
The aim of the present study is to synthesize and characterize Fe-doped TiO2 nanoparticles prepared by molten salt method using a precursor of a solid mixture of TiO2 powder and FeCl3. As far as this study is concerned, this is the simplest method that has been reported so far for the synthesis of Fe-doped ...
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The aim of the present study is to synthesize and characterize Fe-doped TiO2 nanoparticles prepared by molten salt method using a precursor of a solid mixture of TiO2 powder and FeCl3. As far as this study is concerned, this is the simplest method that has been reported so far for the synthesis of Fe-doped TiO2 nanoparticles. Pure TiO2 nanoparticles and 0.5, 1 and 3 wt % Fe-doped TiO2 samples were prepared. Characterization of prepared nanoparticles was done by UV-Vis diffusion reflection spectroscopy (DRS), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Energy-dispersive X-ray spectroscopy (EDX). SEM and XRD analysis of the samples indicated the presence of anatase spherical-shaped TiO2 particles. The results of EDX study confirmed the presence of Fe in all of the samples. According to DRS results, the band gap energy of Fe doped TiO2 nanoparticles decreased with increasing Fe concentration from 3.1 eV for pure TiO2 to 3.0- 2.80 eV for Fe-doped TiO2. The photocatalytic activity was also checked. It was found that, the photocatalytic activity of Fe-doped nanoparticles was higher than pure TiO2. The maximum degradation activity of 69% was obtained at the Fe doping content of 0.5 wt%.
Mohammad Ghorbanpour; Mohsen Moghimi; Samaneh Lotfiman
Abstract
In this research, a simple and fast method was employed to synthesize CuO nanoleaves/silica gel nanocomposites (CuO/SGn), which is a cost effective antimicrobial material. CuSO4.5H2O is the only raw material used in CuO/SGn production through the molten salt method. The structure and morphology of the ...
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In this research, a simple and fast method was employed to synthesize CuO nanoleaves/silica gel nanocomposites (CuO/SGn), which is a cost effective antimicrobial material. CuSO4.5H2O is the only raw material used in CuO/SGn production through the molten salt method. The structure and morphology of the nanocomposites were characterized by DRS, XRD, and SEM. The copper size in CuO/SG was found to be dependent on the immersion time in molten salt. SEM images revealed smaller-sized particle leaves, from a sample obtained after longer immersion time.The antimicrobial activity of CuO/SGn was investigated against Escherichia coli. The produced CuO/SGn showed inhibitory effect against E. coli. However, the growth-inhibitory effect depends on the copper content and size. Lower loading of CuO nanoparticles in 10 min immersion time resulted in less antibacterial activity (73.33%) and sample obtained from longer immersion time demonstrated higher antibacterial activity (up to 99.96%). The maximum amount of released Cu ions from nanocomposites produced in 90 min was 12.2 ppm after 6 h. Furthermore, the minimum release of Cu ions was observed by 3 h for 40 min nnanocomposite.