Robab Mohammadi
Abstract
In this research, Fe3O4, Fe3O4/graphene oxide (Fe3O4/GO) and polyaniline-Fe3O4/GO with various content of polyaniline were prepared and characterized by different analysis methods such as XRD, SEM, EDX, and FT-IR. The prepared samples were used to remove methyl red as an anionic dye from aqueous solutions. ...
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In this research, Fe3O4, Fe3O4/graphene oxide (Fe3O4/GO) and polyaniline-Fe3O4/GO with various content of polyaniline were prepared and characterized by different analysis methods such as XRD, SEM, EDX, and FT-IR. The prepared samples were used to remove methyl red as an anionic dye from aqueous solutions. Polyaniline-Fe3O4/GO nanocomposite showed high catalytic activity, which is partly because of the sensitizing influence of polyaniline and the low recombination rate due to the graphene oxide electron scavenging property. The photodegradation reaction fit well to a Langmuir-Hinshelwood kinetic model implying the reaction rate is depended on initial adsorption step. Also, in polyaniline-Fe3O4/GO samples, the polyaniline content can play a significant role in affecting photocatalytic activity of photocatalysts. Based on results, when the content of polyaniline is more increased above its optimum value, the photocatalytic performance decreased. Furthermore, the efficiency of polyaniline-Fe3O4/GO nanocomposite was investigated to compare between adsorption and photodegradation of methyl red from aqueous solution. Based on results, the removal rate of methyl red via polyaniline-Fe3O4/GO nanocomposite under photocatalytic process was considerably higher than the adsorption process. To understand the nature of adsorption procedure, the equilibrium adsorption isotherms were investigated. The linear correlation coefficients of Langmuir and Freundlich isotherms were obtained. Based on results, Langmuir isotherm model fitted the experimental data better than Freundlich isotherm model. According to the Langmuir isotherm model, the maximum adsorption capacity of polyaniline-Fe3O4/GO nanocomposite for sequestering methyl red was about 101.72 mg g–1.
Robab Mohammadi; Bakhshali Massoumi; Amin Mashayekhi
Abstract
In this research, Fe3O4, Fe3O4/polystyrene and Fe3O4/polyaniline nanocompounds were prepared and compared on the removal of methyl orange from aqueous solutions. The chemical structures of the synthesized compounds were studied using FT-IR. The crystalline phase of Fe3O4, Fe3O4/polystyrene and Fe3O4/polyaniline ...
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In this research, Fe3O4, Fe3O4/polystyrene and Fe3O4/polyaniline nanocompounds were prepared and compared on the removal of methyl orange from aqueous solutions. The chemical structures of the synthesized compounds were studied using FT-IR. The crystalline phase of Fe3O4, Fe3O4/polystyrene and Fe3O4/polyaniline nanocompounds was characterized by XRD. SEM was used for detecting morphology of the synthesized samples. The magnetic property of the prepared samples was successfully checked. The prepared nanocompounds were used to remove methyl orange as an anionic dye from aqueous solutions. Based on results, Fe3O4/polyaniline nanocomposite showed higher efficiency in the removal of methyl orange, which is partly due to the oppositely charged methyl orange and Fe3O4/polyaniline. Effective variables on the removal of methyl orange such as adsorbent dosage, pH, and contact time were studied and optimized. At the optimum situations the pH, catalyst dosage, and time were 3-4, 450 mg L-1, and 50 min, respectively. For detecting the type of adsorption isotherm, Langmuir, Freundlich, and Dubinin Radushkevich adsorption isotherms were studied. According to Langmuir model, Fe3O4/polyaniline magnetic absorbent showed the highest methyl orange adsorption capacity of 48.76 mg g−1. Kinetic studies proved that methyl orange adsorption was explained more accurately via pseudo-second order model compared to the pseudo-first order model. Under controlled reaction conditions, Gibbs free energy (ΔG˚) varied from -1.41 to -1.69 kJ mol-1, besides, the resulting ΔH˚ and ΔS˚ quantities were obtained 4.07 kJ mol-1 and 0.018 kJ mol-1K-1, respectively. Therefore, it can be considered that the adsorption of methyl orange onto the Fe3O4/polyaniline magnetic absorbent is a spontaneous and endothermic procedure.
Robab Mohammadi; Milad Alizadehlarijan
Abstract
In this research, Fe3O4 and Fe3O4/Graphene materials were prepared and characterized via different techniques such as X-ray diffractometer (XRD), Vibrating Sample Magnetometer (VSM), and energy-dispersive X-ray spectroscopy (EDX). The efficiency of prepared samples were investigated by elimination of ...
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In this research, Fe3O4 and Fe3O4/Graphene materials were prepared and characterized via different techniques such as X-ray diffractometer (XRD), Vibrating Sample Magnetometer (VSM), and energy-dispersive X-ray spectroscopy (EDX). The efficiency of prepared samples were investigated by elimination of methylene blue as a cationic dye from aqueous solutions via different methods such as adsorption, photodegradation and sonodegradation processes. The results indicated that the degradation rate of methylene blue by Fe3O4/Graphene nanocomposite under sonocatalytic process was considerably higher than the adsorption and photocatalytic procedures. Sonocatalytic degradation of methylene blue by Fe3O4/Graphene nanocomposite could be explained by the mechanisms of hot spots and sonoluminescence. The degradation pathways between sonocatalytic oxidation and methylene blue solution was described. The results showed that the conjugate structure of nitrogen-sulfur heterocyclic material was broken and aromatic ring was oxidized to open the ring. Methylene blue molecules were finally mineralized to H2O and CO2 in the sonocatalytic degradation process. Furthermore, the figures-of-merit based on electric energy consumption (electrical energy per order (EEO)) were estimated in the degradation of methylene blue in the presence of Fe3O4/Graphene nanocomposite. The results showed that less energy is consumed during the sonodegradation of methylene blue in the presence of Fe3O4/Graphene nanocomposite in comparison with photodegradation procedure.
