Document Type : Research Paper
Authors
Department of Chemistry, College of Science, University of Kerbala, Kerbala, Iraq
Abstract
Keywords
INTRODUCTION
Numerous practical uses for nanotechnological materials have attracted researchers to this topic [1]. One of the most prevalent types of magnetic nanoparticles (NPs) is enticing nanomaterials with a wide range of uses, particularly in the fields of magnetic data storage, magnetic resonance imaging, magneticuids, biotechnology/biomedicine, high performance inductors, catalysis, and environmental cleanup. Nanomaterials are frequently governed by their properties and uses [2-4]. Rapid development is occurring in nanotechnology. The growing usage of nanotechnology products, especially for biomedical applications, has also sparked worries about the emergence of unanticipated adverse health effects following exposure. It is crucial to comprehend the toxicological profiles of engineered nanomaterials to guarantee that these materials are safe for use and are ethically produced with a focus on benefits and a reduction in risks. However, the creation and manufacture of engineered nanomaterial’s are growing more quickly than the production of toxicological data [1]. Magnetic IONPs are frequently employed as drug carriers in the treatment of cancer [6, 7], magnetic resonance imaging (MRI) agents [8, 9], bio-separation [10, 11], gene delivery [12, 13], biosensors [14, 15], protein purification [16, 17], immunoassays [18, 19], and cell labeling [20, 22]. This is based on recent research and published literature. They are commonly employed in the management of hyperthermia [22, 23]. The three forms of iron oxides that are most frequently found in nature are magnetite (Fe3O4), magnetite (Fe2O3), and hematite (Fe2O3). These oxides will be the subject of this examination because they are also essential to scientific advances. Super para-magnetism, a special form of magnetism, is displayed by NPs manufactured of ferromagnetic materials and measuring 10–20 nm or less [24]. An adequate statistical description is particularly challenging when it comes to solid materials because of their variability, including porous adsorbents, which make up the majority of industrial adsorbents. Under the assumption that the surface and bulk phases are in thermodynamic equilibrium, we can generate various adsorption isotherms by employing the equality of the chemical potentials of a specific component in coexisting phases. How these equations can be analytically represented depends on the proposed models for the surface and bulk phases. The surface phase can be classified as monolayer or multilayer, confined, mobile, or partially mobile. The analytical forms of adsorption isotherms are difficult to understand because solid surfaces have structural and energetic heterogeneity, which is a characteristic of a wide range of adsorbents used in practice [25, 26].
The equilibrium between a bulk phase and the surface layer can be attained with reference to neutral or ionic particles. Ion exchange is a process in which an equal number of ionic species are concurrently adsorbed and desorbed. Physical adsorption, also known as physisorption or universal van der Waals interactions can both lead to adsorption. Alternatively, it could resemble a chemical process, such as chemical adsorption or chemisorption. Chemisorption, a contrast to physisorption, only takes place as a monolayer[2]. That will similar to the physical adsorption to the adsorptive condensation process. It often happens at a temperature below or very near the critical temperature of an adsorbed material and is reversible. Therefore, the current study is aimed to synthesize and characterize two prepared types of magnetic iron oxide nanoparticles with and without using of cetramide. Both prepared iron oxide nanoparticles were investigated and compared considering different factors such as FT-IR, XRD, SEM and EDX spectra. The effect of dye concentration was also used to assess the adsorption kinetics and isotherms. Moreover, the acquired experimental findings were used to determine the thermodynamic parameters (∆G°, ∆H°, and ∆S° ).
MATERIALS AND METHODS
Materials
In this experiment, the sodium nitrate NaNO3, sodium hydroxide NaOH, and ferric sulfate FeSO4.7H2O were used all provided by BDH. Surfactants like cetramide were supplied by Qualikems. Eosin yellow dye, which provides information as indicated in Table 1, was donated by the CDH.
Synthesis of Spinel Fe3O4 nano crystals
A 2.0 g of FeSO4•7H2O was put in 400 mL beaker size and then had been dissolved in 150 mL of water. A 50 mg of NaNO3 and 0.56 g of NaOH were transferred to 100 mL beaker size, and then dissolved in 60 mL of water. The two solutions were heated at 75 oC for 10 minutes. The last solution was mixed with a stirring rod rather than a magnetic stir bar. The resulting heated solution was picked up with a tong. The suspension initially turned green before quickly turning black. The black color suspension was continuously heated to 90 oC for ten minutes, and then cooled to 20 oC before being acidified with three millilitres of concentration HCl. This murky fluid was filtered by the Buchner funnel. The Buchner funnel was used to filter this dark solution.
The resulting black precipitate was washed twice with 50 mL of water to get rid of all the salts, and it was then dried in the oven at 100 oC for 60 minutes. As depicted in Fig. 1, the black powder was scraped from the filter paper. The chemical reactions of spinel Fe3O4 formed without and with surfactant were suggested using the following equations.
Removal of Eosin yellow dye using synthesized spinel Fe3O4
The 0.01 g of prepared Fe3O4 samples with the 6.5 pH was added to 5 mL of the 10 mg/L the eosin yellow dye solution in the beaker. This solution was shaken with a shaker for 10 to 60 minutes at 50 rpm and 22 oC. Both were taken up by the magnet after the dye had been adsorbed on the Fe3O4 surface. Using a UV-visible spectrophotometer set to measure the absorbance of solution after adsorption at 516 nm, the amount of adsorption Ce was determined by measuring the residual dye concentration after adsorption depended on the calibration curve. Equation 3 was used to calculate the dye removal quantity of absorption (q m)[3, 4] using various types of produced nanoparticles.
RESULTS AND DISCUSSION
Synthesis of Iron oxide NPS
The major goal of this work was to create magnetic iron oxide utilizing hydrated iron sulphate without and with the addition of a surfactant like cetramide. Some Fe(II) was changed to Fe(III) by partially oxidizing it with sodium nitrate while also being in the presence of a base medium made of NaOH. To ensure appropriate growth, the general method of organizing the prepared Fe3O4 NP in the presence of surfactant as template was examined.
Characterization of the prepared Fe3O4 nanoparticles
A.FT-IR Analysis
FTIR spectra appeared for magnets prepared in Fig. 2 without and with using cetramide. The black line (a) for spinal Fe3O4 occur the wide peak at 3163.36 cm-1 belonging the O - H group, in addition to the peak at 1100 cm-1 explaining the O-Fe-O as an octahedron bending. As for the Fe-O bonding, it is in locations between 640 cm-1 and 598 cm-1 that present the tetrahedral curvature. The red line (b) for Fe3O4 + cetramide shows the broad peak at 3082 cm-1 beyond the O–H stretching of the iron oxide. This decrease in wave number refers to a decrease the energy and an increase the stability after addition cetramide as positive surfactant. Another peak at 3028 cm-1 assigned to the N–H bending in addition to the peaks between 2924 cm-1 and 2850 cm-1 represent stretching C-H. The peak at 1211 cm-1 explains the O–H bending. The more intense bands between 744 cm-1 and 598 cm-1 represent to Fe-O octahedral and tetrahedral bending [5].
Structure Property
X-ray diffraction (XRD) measurements in Fig. 3 (black and blue lines) were used to obtain the crystal structure of the prepared magnetic iron oxide nanoparticle without and with of cetramide surfactant respectively. The appearance of diffraction peaks at 2θ values of 18.96°(111), 30.4° (220), 35.64° (311), 43.4° (400), 53.16° (422), 57.32° (511), 63.12 ° (440), and 73.12° (553) are consistent with the standard XRD data of the structure of spinel Fe3O4. It was also observed that some values disappeared and their relative intensity changed with use of surfactants, where the peak at 2θ values of 18.96 ° (111) disappeared when using cetrimide. The increase in the relative strength of the 35.64 ° peaks. (311), 43.4 ° (400), 53.16 ° (422), 57.32 ° (511), 63.12° (440), and 73.12 ° (553) the prepared nanoparticles in the case of using ceramide. The magnetite nanoparticles for all shapes in Fig. 3 (a&b) are well crystalline and the position and the relative intensity of the diffraction peaks match well with the standard phase magnetite NPs diffraction pattern of the International Center of Diffraction Data card (JCPDS No. 19-0629)[6].
The mean crystal sizes (D) of the synthesized magnetite nanoparticles without and with the presence of surfactants were calculated using Debye-Scherer formula [7].
Where β is the full width at half-maximum value of XRD diffraction lines, λ is the wavelength of X-ray radiation source 0.15405 nm. β = the half diffraction angle –Bragg angle and k refers to the Scherer constant with a value from 0.85 to 0.94. The mean crystal size of iron oxide NP without cetramide was 8.5 nm regarded as a quantum dote nanoparticle because its size value is less than 10 nm, this value is the same as another nanoparticles studies reported in references [8]. However, after adding the cetramid surfactant during iron oxide NP preparation, the mean crystal size increases from 8.5 nm to 22.53 nm due to the behavior of surfactants as a template.
SEM analysis
One of the most important techniques for studying various surfaces and the changes that occur on them is the scanning electron microscope (SEM) in Fig. 4.
According to Fig. 4 (a & b) for SEM analysis, the particle size of iron oxide NP without and with the use of cetramide surfactant increased with the following sequences: 20.30 nm and 50.42 nm respectively. This behavior indicates that all prepared NP without and with using of cetramide surfactant are polycrystals; these findings are consistent with other findings reported in [9, 10].
Sorption isotherm model
Adsorption isotherms are thought to be one of the most important requirements for determining the relationship between adsorbent and adsorbate. They are also of high quality, highlighting the significance of achieving and the most effective dyeing style removal [11]. Furthermore, they are critical in explaining particle distribution between the two phases in the equilibrium state, and there are several models available. It has been used in the literature by Langmuir, Freundlich, and others [11]. This study employed the Langmuir and Freundlich models, which were chosen as follows: The Langmuir isotherm equation[12].
Where qe is the amount absorbable per unit mass of sorbent material at equilibrium (mg/g), qm is the maximum sorption capability (mg/g), Magnetite nanoparticle concentration at equilibrium (Ce) is measured in mg/L., and Ka is the sorption constant. In equation ( 6 ), the plot of Ce/qe versus Ce is linear.
The essential characteristics of the Langmuir model can be defined by a dimensional constant known as the equilibrium parameter, RL [14] ,which is definite by:
Where b represents the Irving Langmuir constant and Co represents the initial concentration of dye, the value of RL (R2) indicates whether the line is unlucky (RL > 1), linear (RL = 1) and permanent (RL = 0).
As results, the dye sorption onto Fe3O4 with and without cetramide surfaces was occurred in table 2.
The Freundlich isotherm equation[13] was applied as equation 8.
Where qe is the amount of adsorbate per unit mass of adsorbent at equilibrium (mg/g) and Ce is the solution’s equilibrium of dye (mg/L). Kf and n are the Freundlich constants, with n providing a sign of favorability and Kf = (mg g-1)(L mg-1)1/n. The values of Kf and n are obtained from the log qe versus log Ce plot in Fig. 5, and they are capable of calculating the intercept and slope of the several times. The n value is near 1 for adsorption of dye on prepared Fe3O4 using cetramide that indicates to chemisorption and Freundlich model is more obeyed than Langmuir equation. As shown in Fig. 5 and 6 and listed in Tables 2 and 3. The adsorption process of dye using prepared Fe3O4 without and with using cetramide as surfactant is found to be physical adsorption and chemical adsorption, respectively.
The Kinetic and thermodynamic studies of removal of eosin yellow dye using Fe3O4 NPS without and with cetramide
The thermodynamic parameters are critical in determining the type of adsorption process that occurred on any solid surface. To begin, the sorption distribution coefficient (kd) [14, 15]was calculated using equation 9, where Cads. is the amount of adsorbate (dye) on the solid surface (prepared Fe3O4 without and with using cetramide) at equilibrium (mg/L), and Ce is a residual dye (mg/L) in an equilibrium solution. The Gibbs energy (∆G0) was calculated using equation 10 (Gibbs equation), where R is the universal gas constant (J/mol K) and T is the absolute temperature in (K).
The difference in enthalpy ΔHo and entropy ΔSo were measured using the Van’t Hoff equation [16, 17]. (equation 11).
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On the other hand, the activation energy (Ea) was determined using equation 12 [4, 17].
There are comperes between magnetite with and without surfactant, for Fe3O4 prepared by cetramide as the findings in Figs. 7 and 8. The results in Table 4 determined that the eosin yellow dye’s adsorption process on the surface of the Fe3O4 using cetramide is endothermic in nature and has a positive magnitude of ∆Ho value equal to (36.729 kJ mol-1). This result, which is greater than (4.2) kJ mol-1 [16], indicates that the adsorption mechanism is chemisorption. Furthermore, the ∆So magnitudes are little and positive (0.14467 kJ mol-1), which suggests that there is an increase in randomness at the solid/solution interface. The fact that the activation energies in Table 4 are positive and rise as temperature rises, from (39.040 to 39.248) kJ mol-1, that indicates to the process is chemisorption, due to the activation energies having a range between 8.4 kJ mol-1 and 83.7 kJ mol-1 [16]. That the process of adsorption occurs as a result of a change in the internal structure [16, 18]. In Fig. 8, the ∆Go demonstrated that the adsorption reaction of dye on prepared Fe3O4 using cetramide is also endothermic; this result is in agreement with that report in [46].
According to using the prepared Fe3O4 without cetramide, the findings in Fig. 7 and Table 4, it is determined that the eosin yellow dye’s adsorption process on the surface of the prepared Fe3O4 without cetramide has a negative magnitude of ΔHo (exothermic in nature) and is equal to (-149.827 kJ mol-1). This value is found to be less than (4.2) kJ mol-1 that indicates that the adsorption process is physisorption.The ∆Go value is also exothermic; as shown in Fig. 8, this result is in agreement with that report in [46]. Additionally, the ΔSo magnitudes are tiny and negative (-0.5073 kJ mol-1), implying that there is a decrease in randomness at the solid/solution interface and that the mechanism of adsorption occurs as a result of a change in the internal structure, hence, sorption process may have occurred. In table, the activation energies are negative values that decrease with a rise in temperature to give a range from (-147.433 to -147.308) kJ mol-1, proving that the process is physisorption because the activation energies value is less (8.4 and 83.7) kJ mol-1 and may be multistep can be happened during adsorption.
CONCLUSION
Two distinct magnetite Fe3O4 nanoparticles (NP) were created with and without cetramide. Fe3O4 was shown to exhibit greater adsorption when created it in presence cetramide as a template to improve the growth. On the basis of the locations of the octahedron and tetrahedron peaks, FT-IR analysis determined that the magnetic iron oxide nanoparticle is inverse spinel type. XRD indicated the prepared Fe3O4 NP without cetramide is being as a quantum dot nanoparticle. According to the SEM examination, both samples are nanoparticulate and produced shapes resembling a spherical like brooklei. Because of the prepared Fe3O4 NPs with and without using cetramaide have magnetic properties, so, they used to remove the eosin yellow dye from aqueous solutions. The dye adsorption takes one of two forms: chemisorption; in the case of magnetite with cetramide, while physisorption and sorption for magnetite NP without cetramide. The dye adsorption data were well-fit by the Freundlich models and magnetite prepared in presence of cetramide is better fitted compared the magnetite alone. The strength of the dye’s adhesion to the nanoadsorbents was influenced by surfactants. According to the research, iron oxide made with cetramide is a potent adsorbent for absorbing anionic dye and can be used to filter out pollutants from water. The reaction of removal is endothermic using prepared Fe3O4 in presence of cetramide while is exothermic using Fe3O4 alone.
CONFLICT OF INTEREST
The authors declare that there is no conflict of interests regarding the publication of this manuscript.
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