Original Research Paper
Sheetal .; Savita Sihag; Monika Yadav; Jitender Pal
Abstract
This study is focused on the synthesis and characterization of cotton straw residue. Nanocellulose was synthesized by chemical method and followed by ultrasonication and cryocrushing. The results of the present study show that the cotton straw residue consists of lignin (27%), hemicellulose (15%), cellulose ...
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This study is focused on the synthesis and characterization of cotton straw residue. Nanocellulose was synthesized by chemical method and followed by ultrasonication and cryocrushing. The results of the present study show that the cotton straw residue consists of lignin (27%), hemicellulose (15%), cellulose (32%), and ash content (2.3%). Nanocellulose was characterized by FTIR, XRD, FESEM, TEM, DSC, TGA, and AFM. Two aromatic rings were observed at wavelength 1650.47cm-1 and 1436.53 cm-1 which indicates that there is a presence of cellulose in the prepared sample which was characterized by FTIR. The structural analysis shows that the material was amorphous and the nanocellulose crystallinity is 23 %. The morphological analysis using FESEM indicates even elongated fiber with a smooth surface and it contains pore in the nanocellulose of cotton residue. TEM analysis indicates that nanocellulose has an irregular shape with a circular rod-like structure of different sizes. The enthalpy of nanocellulose changes at 168.48℃ due to endothermic transition. TGA results show that the nanocellulose is degraded in the temperature range 300-355℃ and low thermal stability was observed during the experiment. AFM result shows the needle shape particle ( root square mean roughness = 0.1738nm) and the size of nanocellulose was observed 7.1 nm.
Original Research Paper
Mona Nabizad; Ahmad Dadvand Koohi; Zahra Erfanipour
Abstract
In this study, alginate, magnetite, and hydroxyapatite were used to fabricate alginate-hydroxyapatite (Alg-Hap), alginate-Fe3O4 (Alg-Fe3O4), and alginate-magnetic hydroxyapatite (Alg-mHap) using ferric chloride (III) crosslinker to remove cefixime from an aqueous solution. FTIR, SEM, VSM, BET, and XRD ...
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In this study, alginate, magnetite, and hydroxyapatite were used to fabricate alginate-hydroxyapatite (Alg-Hap), alginate-Fe3O4 (Alg-Fe3O4), and alginate-magnetic hydroxyapatite (Alg-mHap) using ferric chloride (III) crosslinker to remove cefixime from an aqueous solution. FTIR, SEM, VSM, BET, and XRD tests were used to determine the functional groups, morphology, magnetization behavior, surface area, and crystallinity of catalysts, respectively. The optimal pH for the Fenton reaction was determined to be 3.3 for Alg-Hap and Alg-Fe3O4 catalysts and 4 for Alg-mHap catalysts. Increases in the concentration of hydrogen peroxide (1 to 3 mM) and the amount of catalyst (50 to 90 gr/L) increased the percentage of degradation to approximately 8% and 6%, respectively. The degradation efficiency of cefixime by using Alg-mHap as the best catalyst in the Fenton process was achieved 91%, at optimum condition (pH of 4, catalyst amount of 90 gr/L, initial cefixime concentration of 5 mg/L, H2O2 concentration of 3 mM within 90 min). Moreover, the second-order kinetic equation fits the experimental data for cefixime degradation for all three catalysts. Furthermore, not only did the catalysts display a negligible iron leaching (0.92 mg/L for Alg-mHap) but also after three consecutive cycles, the catalysts indicated long-term stability. Comparison between synthesized catalysts and other methods proved its effectiveness.
Original Research Paper
Taher Yousefi; Ramin Yavari; D Rezaei Uchbelagh; Abbas Ariamanesh
Abstract
Al-Ce-Mn oxide samples were synthesized by the cathodic electrochemical method at current densities of 5, 15, and 35 mAcm-2. The XRD, SEM, and EDX techniques were used for the characterization of samples. The SEM images show that at high current density the one-dimensional(nanowire) structure and at ...
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Al-Ce-Mn oxide samples were synthesized by the cathodic electrochemical method at current densities of 5, 15, and 35 mAcm-2. The XRD, SEM, and EDX techniques were used for the characterization of samples. The SEM images show that at high current density the one-dimensional(nanowire) structure and at low current density two-dimensional (nanosheet) structure were obtained. Moreover, the particle sizes are decreased with increasing the current density. The samples were applied for the uptake of fluorine (F-) ions from solutions. The influence of the contact time, initial fluoride concentration, and solution pH on the adsorption was investigated. The results showed more than 80 % of F- ions were uptake from solution during the three hours initial contact times and the uptake capacity has little change at pH below 6 and it has a sharp decline with increasing solution pH. The kinetic data were well fitted to the pseudo-second-order model and the equilibrium adsorption data was well described by the Langmuir isotherm model. The adsorption capacity was 48 mg/g at pH 6 and room temperature.
Original Research Paper
Alireza Behzadi; Amirhosein Yazdanbakhsh
Abstract
Recently, there has been growing concern about the presence of pharmaceutical compounds and particularly antibiotics as emerging contaminants. This study employed high specific surface area organic aerogels to remove Tetracycline antibiotics. For this purpose, resorcinol formaldehyde aerogel (RF) was ...
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Recently, there has been growing concern about the presence of pharmaceutical compounds and particularly antibiotics as emerging contaminants. This study employed high specific surface area organic aerogels to remove Tetracycline antibiotics. For this purpose, resorcinol formaldehyde aerogel (RF) was synthesized via the sol-gel process and dried under ambient drying conditions. The synthesized RF aerogel was modified by incorporating 1 wt.% graphene with 1 wt.% m-phenylenediamine during the synthesis process to prepare RF-G1/PmPDA1. Eventually, the performance of the synthesized samples as adsorbents was evaluated under various parameters such as the effects of pH values (2-12), adsorbent dose (4-10 mg), and adsorbent with antibiotics contact time (3-24 h). FTIR, FESEM, BET, CHN, and EDS tests were conducted to characterize the samples. Afterward, the adsorption rate of Tetracycline antibiotics was measured using UV-Vis. The BET test results revealed that the modification of the RF aerogel sample also increased the specific surface area from 96 to 308 m2/g. The results also discovered that the removal rate of Tetracycline antibiotics for the RF aerogel and RF-G1/PmPDA1 was obtained to be 65.2% and 93.3% at optimal pH of 4 and 4, respectively.
Original Research Paper
Fatemeh Shahverdi; Aboulfazl Barati; Mansour Bayat
Abstract
This research work aims to investigate the sorption characteristic of synthesized Poly (vinyl alcohol)/Chitosan nanofiber mats modified with aluminum-cerium spinel oxide (CeAlO3) nanoparticles for methylene blue (MB) removal from aqueous solutions. The sorption is carried out by a batch technique. The ...
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This research work aims to investigate the sorption characteristic of synthesized Poly (vinyl alcohol)/Chitosan nanofiber mats modified with aluminum-cerium spinel oxide (CeAlO3) nanoparticles for methylene blue (MB) removal from aqueous solutions. The sorption is carried out by a batch technique. The structural characterization of this nanocomposite was performed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD). Scanning electron microscopy (SEM) results showed uniform net and improved nanofibers with diameters ranging about 420 and 450 nm, respectively. The optimum conditions of MB removal onto modified PVA/CS nanofibers were found to be: pH 10, contact time 45 min, and 0.01 g of adsorbent in 400 ml in aqueous solution. Furthermore, the experimental adsorption data were in excellent agreement with the pseudo-second-order kinetics. The experimental results showed that there is a good correlation between the obtained data and the adsorption isotherm in the concentration range studied (400-600 mg/l). The results revealed that the maximum adsorption capacity of MB was 817.81 and 714.61 mg/g onto improved and net nanofibers, respectively.
Original Research Paper
Sadegh Roushenas; Maryam Female Nikzad; Ali Asghar Ghoreyshi; mohsen ghorbani
Abstract
In this study, pectin/γ-Fe2O3/gl nanocomposite was synthesized using a single-step chemical precipitation method and used as an eco-friendly adsorbent to remove Cd2+ and Pb2+ from aqueous solution. The nanocomposite was characterized by FE-SEM, EDX, FTIR, XRD, VSM, and TEM analyses. The effect ...
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In this study, pectin/γ-Fe2O3/gl nanocomposite was synthesized using a single-step chemical precipitation method and used as an eco-friendly adsorbent to remove Cd2+ and Pb2+ from aqueous solution. The nanocomposite was characterized by FE-SEM, EDX, FTIR, XRD, VSM, and TEM analyses. The effect of various parameters such as solution pH (2 to 5), contact time (0 to 60 min), initial ion concentration (10 to 200 mg. L-1), and adsorbent dosage (0.1 to 0.4 g.L-1) on the removal efficiency was investigated. The maximum adsorption capacity of Cd (II) in the conditions (pH: 5, dose of adsorbent: 0.2 g.L-1, and contact time:40 min, initial concentration: 50 mg.L-1 ) and Pb (II) in the conditions (pH: 4.5, dose of adsorbent: 0.1g.L-1, and contact time:30min, initial concentration: 50 mg.L-1 ) was 470 and 325 mg. g-1, respectively. The adsorption kinetics was studied using several kinetic models including Langmuir isotherm, Freundlich isotherm, Sips isotherm, and Temkin isotherm. Results indicated that the adsorption mechanism could be well represented by the pseudo-second-order model. The equilibrium data of Cd (II) and Pb (II) adsorption were reasonably described by the Sips and Langmuir isothermal models. The positive value of delta H and negative values of delta G exhibit the endothermic and spontaneous nature of the adsorption process.
Original Research Paper
Dhanraj S Shirsath
Abstract
Magnetic nano adsorbent is cost-effective and easily synthesized in the laboratory by chemical Co-precipitation method that provides not only high adsorption capacity but also rapid adsorption rate. The magnetic nano adsorbents were synthesized by Ferric and Ferrous ions precursor solution in the presence ...
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Magnetic nano adsorbent is cost-effective and easily synthesized in the laboratory by chemical Co-precipitation method that provides not only high adsorption capacity but also rapid adsorption rate. The magnetic nano adsorbents were synthesized by Ferric and Ferrous ions precursor solution in the presence of ammonium hydroxide. In the present investigation, a magnetic nano adsorbent has been employed for the removal of Pb (II) from an aqueous solution by batch adsorption technique along with photocatalysis. The different parametric study also carried out such as initial concentration of Pb (II), adsorbent dose, contact time, and Solution pH. The Pb (II) was fast adsorption and the equilibrium was achieved within 45 minutes. The amount Pb (II) adsorbed increases as the temperature increase. The optimal pH for Pb (II) was around 5.4 and for the removal of Pb (II) ions was up to 96.00%. The employed adsorbents were characterized by SEM, X-ray diffraction (XRD), Vibrating spinning magnetometer (VSM), and FTIR. The Kinetic of adsorption study was examined for the pseudo-first-order model and pseudo-second-order models. This Photocatalytic adsorption study obeys Pseudo second-order kinetic. The reusability and regeneration of magnetic nano adsorbents were studied and were recycled up to 87.00 %.
Original Research Paper
Maryam Ghasemi; Javad Azimi-Amin
Abstract
Here, graphene oxide was synthesized and reduced by lemon extract (source of vitamin C) in an aqueous solution under different pH (3 and 10). The lemon extract was prepared using a solvent-free method. The proposed mechanisms for the reduction of GO may be due to the nucleophilic attack of oxygen anion ...
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Here, graphene oxide was synthesized and reduced by lemon extract (source of vitamin C) in an aqueous solution under different pH (3 and 10). The lemon extract was prepared using a solvent-free method. The proposed mechanisms for the reduction of GO may be due to the nucleophilic attack of oxygen anion of ascorbic acid to the epoxy or hydroxyl groups of GO sheets. Based on Raman spectra, with increasing the solution pH, the repair of the graphitic sp2 domain of the RGOs decreased. Reduced graphene oxide was successfully used to synthesize Fe3O4/RGO nanocomposite and remove Pb ions from aqueous media. The obtained Fe3O4/RGO nanocomposite was characterized by XRD, FTIR, SEM, and BET analysis. Based on these characterization techniques, reduced graphene oxide is distinguishably coated by Fe3O4 nanoparticles. The effect of different parameters: contact time (1-60 min), initial lead concentration (25-200 mg/L), adsorbent dosage (0.01-0.07 g), and the solution’s initial pH (1-8) on the removal of lead ions was studied using batch-scale tests. The maximum lead ion removal was achieved up to 90 % for Pb ions, respectively at optimum operating conditions viz. pH 5, Pb initial concentration 100 mg/L, Fe3O4/RGO dose 0.05 g, and contact time 30 min. Obtained results showed that the maximum adsorption capacity of Fe3O4/RGO for lead ion was 107.52 mg/g within 60 min of contact time. The adsorption behavior can be well described with the Langmuir isotherm and the pseudo-second-order models, indicating that the adsorption process was a monolayer and chemisorption adsorption.