Assessment of the synthesis method for purity and particle size of Fe3O4 magnetic nanocatalysts and its effectiveness on viscosity reduction and upgrading of heavy oil

doi:10.21203/rs.3.rs-2975914/v1

Download PDF

Article

Assessment of the synthesis method for purity and particle size of Fe3O4 magnetic nanocatalysts and its effectiveness on viscosity reduction and upgrading of heavy oil

https://doi.org/10.21203/rs.3.rs-2975914/v1

This work is licensed under a CC BY 4.0 License

Journal Publication

published 24 Oct, 2023

Read the published version in Scientific Reports →

You are reading this latest preprint version

In this research, Fe₃O₄ nanocatalysts were synthesized systematically microwave-assisted. For the first time, the efficiency of the synthesized nanocatalysts in reducing viscosity and upgrading heavy oil was examined. The nanocatalysts were investigated for their magnetic and electromagnetic properties. Furthermore, the effect of the time and power of microwave radiation was investigated for the first time on the size and purity of nanocatalysts. By reducing the time and power of microwave radiation due to less heat production, the purities in the crystal network of Fe₃O₄ nanocatalysts expanded. Increased temperature leads to dope NH₄Cl into the Fe₃O₄ crystal network. At: 1 minute and power of 400 watts had the most satisfactory results in the size and purity of nanocatalysts. For the first time, the effect of the synthesis method on the electromagnetic properties, size, and effectiveness of the synthesized Fe₃O₄ has been examined. The performance of Fe₃O₄ synthesized by co-precipitation and microwave in viscosity reduction and heavy oil upgrading was evaluated and compared. The crystallite size of the Fe₃O₄ synthesized with microwave-assisted was smaller than synthesized by the co-precipitation. Fe₃O₄ synthesized by microwave and the co-precipitation method lead to decreased viscosity by 28% and 23% respectively. Also, microwave-synthesized Fe₃O₄ reduced the sulfoxide index and aromatic index significantly more than the co-precipitated synthesized Fe₃O₄ (90% vs. 48% and 13% vs. 7%, respectively).

Physical sciences/Nanoscience and technology

Physical sciences/Nanoscience and technology/Nanoscale materials

Physical sciences/Nanoscience and technology/Nanoscale materials/Magnetic properties and materials

Fe3O4 nanocatalyst

microwave-assisted synthesis

electromagnetic properties

heavy oil

viscosity

upgrading

The time and power of microwave radiation play an essential role in microwave-assisted synthesis. By increasing the irradiation time and microwave radiation power, NH₄Cl impurity enters the nanoferrocatalysts structure and reduces the purity of the nanoferrocatalysts.
During microwave heating, nanoferrocatalysts cause synergy and increase absorption of waves by nanoferrocatalysts, increasing molecular movements, polarity, and heat generation. Thus, these could further reduce heavy oil viscosity.
Nanoferrocatalysts synthesized by microwave-assisted compared to nanoferrocatalysts synthesized by the co-precipitation method have caused a significant reduction in the viscosity of heavy oil. Also, microwave-synthesized Fe₃O₄ reduced the sulfoxide index and aromatic index significantly more than the co-precipitated synthesized Fe₃O₄.

Researchers have recently considered iron oxide nanocatalysts due to their various uses. These nanocatalysts are used in military, medical and pharmaceutical industries, oil extraction, and water or soil treatment [1–3]. One of the reasons for the widespread use of iron oxide nanocatalysts is their magnetic properties[4]. Due to the properties of nanocatalysts, more attention has been paid to these materials [5–7]. The synthesis and preparation of nanocatalysts affect their properties, such as chemical composition, morphology, and particle size, and play an essential role in applying nanocatalysts in various engineering industries. Various methods are used to synthesize Fe₃O₄ nanocatalysts, such as sonochemical, non-hydrolytic, thermal solvent, co-precipitation, sol-gel, and microwave-assisted [8,9].

Microwave synthesis is a fast and straightforward method performed with high yield, less reaction time, highly controlled, and energy efficiency [1,10]. Microwaves are an excellent way to synthesize magnetic iron oxide nanocatalysts with controlled particle size, high crystallinity, and good magnetic properties under a short reaction time [11]. The growth of various industries and global demand for energy resources has led to more attention to the need to use new energy resources. These include unconventional reservoirs or heavy oil reservoirs. It should be noted that using these reservoirs with conventional upgrading and recovery oil methods is challenging or unattainable [12,13]. The cost of producing, refining, and improving oil quality from these reservoirs is higher than average. In-situ upgrading of heavy oil could be an excellent way to produce and upgrade oil from these reservoirs [14,15]. The basis of this method is to cracking of heavy component, reduce the viscosity of heavy oil and increase its mobility [16]. One new and developing in-site heavy oil upgrading method is electromagnetic heating and microwaves. In this method, polar molecules absorb electromagnetic waves and cause molecular fluctuations and friction [17]. As a result of these interactions, heat is generated, and increasing the temperature will reduce the viscosity of heavy oil [12,18]. Metal oxide nanocatalysts absorbing electromagnetic waves are used to increase the penetration range of waves into the reservoirs, such as Fe₃O₄،, ZnO, Al₂O₃, NiO،, BiFeO₃, TiO₂, and MnO₂ [19]. In addition to absorbing electromagnetic waves and increasing the temperature by cracking heavy components such as resin and asphaltene, these nanocatalysts can also decline the viscosity and upgrade heavy oil [14]. Previous research has shown that iron oxide nanocatalysts have been effective among the nanocatalysts used in upgrading and oil recovery processes [20,21].

Considering the catalytic role of Fe₃O₄ nanocatalyst and microwaves in upgrading heavy oil, the authors have used the simultaneous effect of these to synergize the process. It should also be noted that Fe₃O₄ nanocatalysts synthesized with the help of microwaves have yet to be studied and investigated in upgrading heavy oil and enhancing oil recovery. In this research, Fe₃O₄ nanocatalysts were synthesized with the help of microwaves (according to the effective parameters) to reduce the synthesis time and produce appropriate nanocatalysts. Then for the first time, the impact of effective parameters in microwave-assisted synthesis on the quality and efficiency of Fe₃O₄ nanocatalysts was evaluated. Also, in the initial time, the effects of the nanocatalysts synthesis by MW have been assessed in heavy oil upgrading and viscosity reduction of heavy oil. In addition, for the first time, the effect of the synthesis method on the electromagnetic properties, size, and effectiveness of the synthesized Fe₃O₄ nanocatalyst has been examined. The performance of Fe₃O₄ nanocatalyst synthesized by co-precipitation and microwave in viscosity reduction and heavy oil recovery was evaluated and compared.

The present study investigated the synthesis of Fe₃O₄ nanocatalysts using microwave-assisted and, for the first time, presented the effect of this synthesized nanocatalyst on the heavy oil upgrading by the microwave heating process. Iron (III) hexahydrate (FeCl₃.6H₂O), iron (II) chloride tetrahydrate (FeCl₂.4H₂O), and ammonia solution (NH₄OH) were prepared from Merck and Loba Chemie. All materials had an analytical grade and were used directly in this work without further purification and modification. Deionized distilled water (DI) and high purification nitrogen (N₂) were used. The sample of heavy crude oil from one of the oil reservoirs in southern Iran (19.95 API, density 0.9343 gr/cm³and viscosity 295 mPa.s @ 25 °C and 11.7% wt asphaltene content) was used for performing EM absorption. So far, no systematic study has been done on the synthesis of this nanocatalyst with the microwave-assisted and its effect on the microwave heating process; at first, the effective parameters in the synthesis using microwave were determined. Two parameters of radiation time and microwave radiation power were considered the essential effective parameters in this synthesis method. With the help of the general factorial method, experimental design for synthesis was performed by the design expert software.

2.1 Effectual parameters and experiment design

Previous results showed that microwave power and heating time were the main parameters controlling nanocatalyst size and magnetic properties [8]. The general factorial method was used to investigate the effect of critical parameters on synthesis using microwave-assisted and find the optimal combination of synthesis parameters. In this study, two quantitative parameters, power (watts) and microwave radiation time (minutes), were considered to design the experiment using DOE software. The radiation power parameters were assessed at two levels and the irradiation time at three levels, presented in Table 1. Design expert software was used to design the tests. DOE design responses (General Factorial Design) were considered for each experiment's purity of Fe₃O₄ and particle size distribution.

Table 1. Effectual parameters and their levels

parameter	Level 1		Level2
Power (watts)	400		800
parameter	Level 1	Level2		Level3
Time (min.)	1	2.5		5

2.2 Synthesis of Fe₃O₄ nanocatalysts

Initially, 3.43 g of FeCl₂.4H₂O and 9.34 g of FeCl₃.6H₂O were added to the beaker, and 160 ml of deionized water. Also, based on previous research, preheated deionized water was used to synthesize Fe₃O₄ nanocatalysts [8]. The synthesis steps were continued as follows. After adding the precursors to the preheated deionized water, (at 50°C), the mixture was placed in a microwave oven and stirred with a mechanical stirrer. After arranging the time and power of the microwave, according to Table 1, the solution is irradiated with a microwave. During the synthesis, 25 ml of 30% ammonia solution is slowly added to the solution until the pH of the solution reaches 11. The microwave irradiation time was applied in a pulse, and the microwave was turned on for 30 seconds and then turned off for 30 seconds until the selected time expired. This cycle was continued until the pH of the solution was 11. At this stage, a black deposit is formed. After cooling, the solution was taken out from the microwave oven and washed several times with deionized water using magnetic decantation (a permanent external magnet, 0.5T) until the pH of the solution was 7, then dried in an oven at 70 °C for 12 hours. In addition, Fe₃O₄ nanocatalysts have been synthesized by the co-precipitation approach [21]. Furthermore, The implementation of the nanocatalysts synthesized by both methods has been measured. Also, several analyzes were performed to characterize the synthesized nanocatalysts.

2.3 Experimental setup

In this study, the modified home microwave (Feller MW-305) was employed to radiation of electromagnetic waves at the frequency of 2.45 GHz. An infrared thermometer (MASTECH MS6531C) that could measure temperature remotely was utilized. The effect of the Fe₃O₄ nanocatalysts in the microwave heating process was investigated. 50 ml of the oil sample was exposed to microwave radiation at 400 watts. Furthermore, 0.1% by weight of synthesized Fe₃O₄ nanocatalysts was dispersed in 50 ml of crude oil sample. Then the samples were exposed to microwave radiation at 400 watts in a time interval of 0 to 4 minutes. Finally, the samples were cooled to reach the ambient temperature, and their viscosity was taken at the ambient temperature.

3.1 Characterization

3.1.1 XRD analysis

The type of nanocatalysts, texture, crystal orientation, and crystallite size were determined using XRD (X-Ray Diffraction) analysis. Figure 1 shows the XRD pattern of Fe₃O₄ nanocatalysts. By use of the JCPDS No. 00-003-0862, the diffraction at 2θ = 30.17°, 35.5°, 43.3°, 53.6°, 57.6°, and 62.3° corresponds to (220), (311), (400), (422), (511) and (440) crystalline plates of Fe₃O₄ nanocatalysts [22,23] respectively. Consequently, the production of Fe₃O₄ nanocatalysts could be concluded (Fig. 1-A). During synthesizing Fe₃O₄ nanocatalysts, NH₄Cl is formed as a by-product and released by washing the nanocatalysts. However, in some conditions of syntheses, NH₄Cl was not removed by washing. The purity is specified in each of the samples (Table 2). XRD analysis was also performed to determine the crystallite size distribution. The average crystallite size of Fe₃O₄ nanocatalysts synthesized using the Scherer equation (Eq.s1) in different synthesis conditions is estimated between 8 and 12 nm. The magnetic behavior of iron oxide nanocatalysts is very sensitive to crystallinity size. Smaller particle sizes may lead to an increase in saturation magnetism and improve the efficiency of nanocatalysts.

According to Fig. 1-B, with increased power and time in microwave-assisted synthesis, a peak shift towards larger angles appeared in nanocatalysts, which raised the distance between the plates (311) and the lattice constant. During the synthesis by microwave, with the growth in power and radiation time, the temperature also rises, which induces doping NH₄Cl in the Fe₃O₄'s nanocatalysts [25]. It is primarily due to the extensive ionic radius of NH₄⁺ (143 pm) compared to Fe^+ 3 (64.5pm) which is predicted to extend the crystal [26,27]. Furthermore, doping has influenced and decreased the intensity of diffraction peaks to peak displacement. It indicates that doping could decline the crystal order of Fe₃O₄ nanocatalysts. This tendency of modifications is compatible with the results of the XRD analysis.

As mentioned, with the increased time and radiation power in the performed syntheses, the presence of NH₄CL Increased in the structure of Fe₃O₄ nanocatalysts. It should be noted that in the process of electromagnetic or microwave heating, with rising radiation power and irradiation time, the sample temperature, amount of heat produced, and the depth of penetration of waves into materials, especially in electromagnetic absorbers, will increase [28,29]. According to the results presented in Table 1, this increase in temperature during synthesis is confirmed by raising the power and irradiation time. Therefore according to the proposed results, it could be concluded that with increasing the time and power of microwave radiation, the synthesis temperature rises, which causes an increase in impurities in the samples and dopping NH₄Cl to the Fe₃O₄ nanocatalysts.

According to Fig. 1-B and Table 2, it could be found that increasing the time and power of microwave radiation during the synthesis of impurities NH₄Cl is seen ascending in the five samples (No 2, 3, 4, 5, and 6). It should be noted that all samples have been washed frequently using sufficient deionized water to conclude that NH₄Cl is not eliminated by washing, and it dops on the Fe₃O₄ nanocatalysts. The prominent peaks' intensity and displacement would be examined to investigate and prove this issue [25,26] The most substantial diffraction peak from the plane (311) to investigate the peak shift by altering the purity of the samples was determined to examine the structural changes of the crystal unit. Figure 3 shows the magnification of the diffraction intensity from the plane (311). According to Fig. 1-B, the top of the peak changes with increasing impurity towards a greater angle. It means that the network space between the planes (311) changes, and the network space diminishes with further development of impurities [30].

3.1.2 FESEM analyses

According to the results obtained from the XRD results and the purity of the samples, the synthesized sample was further investigated at a radiation time of 1 minute and radiation power of 400 watts using FESEM (Field Emission Scanning Electron Microscope) analysis. Figure 2-A shows the representative FESEM image of Fe₃O₄ nanocatalysts synthesized by microwave-assisted at a power of 400 watts and an irradiation time of 1 minute, which had the most promising result in terms of purity. The spherical structure of synthesized Fe₃O₄ nanocatalysts is observable in the figure. It emphasizes the high efficiency of the synthesis method in this work for producing Fe₃O₄ nanocatalysts. The average size of synthesized Fe₃O₄ nanocatalysts can be 25 nm (Fig. 2-B).

3.1.3 Electromagnetic properties
The Electromagnetic properties of the synthesized sample (at a radiation time of 1 minute and radiation power of 400 watts) were examined. The expression ε' describes the dielectric constant and displays the ability of a compound to polarize due to an external electric field. The term ε'' is the dielectric loss, the efficiency of transforming EM energy into warmness. The electrical conductivity changes of Fe₃O₄ nanocatalysts versus frequency are illustrated in Fig. 3-A. According to the figure and slope of the dielectric constant actual part curve (ε'). The nanocatalysts are satisfactorily affected by the electromagnetic field and are well polarized under these conditions, and similar results were reported by Gharibshahi et al. [14].

The imaginary term electrical permittivity (dielectric loss: ε'') indicates the ability of materials to absorb electromagnetic waves. According to Fig. 3-B, the actual part of the electrical permittivity (ε’) demonstrates the polarization of the nanocatalysts under the electromagnetic field. The imaginary part has a significant slope. Therefore, iron oxide nanocatalysts have acceptable efficiency in absorbing electromagnetic waves.

The loss tangent (tanδ) determines the ability of a material to convert electromagnetic energy into heat at a specific frequency and temperature. Figure 3-C indicates the changes in the loss tangent in a frequency range. The more the tangential substance losses, the more time it could absorb more energy during the electromagnetic heating process and transmit more heat and energy to its surroundings. One of the effective parameters in increasing the capacity of nanocatalysts to absorb and scatter heat in the electromagnetic process is their particle size distribution. According to the results presented in Fig. 3-C and the smaller crystallite size of Fe₃O₄ nanocatalysts synthesized by microwave compared to Fe₃O₄ nanocatalysts synthesized by the co-precipitation method used by Gharibshahi et al. [21]. Therefore, Fe₃O₄ nanocatalysts synthesis by microwave has more ability to absorb and dissipate heat in the electromagnetic heating process. These nanocatalyst has a hopeful potential for use in the electromagnetic heating process and could assist in dissipating heat in heavy oil reservoirs, cracking heavy component, reducing viscosity, and enhancing increasing heavy oil recovery.

3.1.4 Magnetic property measurements

To examine the magnetic properties of Fe₃O₄ samples synthesized-assisted microwave at 400 watts and for 1-minute irradiation, the magnetic curves of Fe₃O₄ samples were analyzed by VSM analysis at room temperature (300 K) by applied field − 6000 to 6000 Oe (Fig. 4). The synthesized sample was found to have a strong magnetic response to a variable magnetic field. In Fig. 6, according to the VSM results of Figure S-type of Fe₃O₄ nanocatalysts, it could be seen that all of these nanostructures are supra-magnetic, and the M-H curves of the Fe₃O₄ samples show a nonlinear characteristic with residue ( Fig. 4). The Fe₃O₄ nanocatalysts synthesized under these conditions had a saturation magnet (Ms) of 46.33 emu/g. The quantity of saturation magnetization of the Fe₃O₄ nanocatalysts synthesis-assisted microwaves is 34.5 emu/g [31]. According to Fig. 4, Fe₃O₄ nanocatalysts dispersed in an aqueous solution are rapidly separated from the solution in the vicinity of a permanent magnetic field to the bottle. This way, these nanomaterials can be easily and quickly separated from the solution by creating a magnetic field using a permanent magnet. It indicates the appropriate magnetic response of the synthesized nanocatalysts.

3.2 Data analysis

As stated, the synthesis of Fe₃O₄ nanocatalysts was carried out according to the general factorial design. The results of the ANOVA Table are presented in Table 2-S. Figure 5 shows the interaction between the power and time of radiation during the synthesis of the purity of Fe₃O₄ nanocatalysts. Based on this figure and the parallelism of the two graphs, it could be concluded that the interaction between the power and the radiation time is low. Also, with increasing power and time, the amount of purity has decreased. It is because with the growth in power and time, the amount of heat produced during the synthesis boosts, and the opportunity for nucleation and growth of Fe₃O₄ nanocatalysts decreases. As a result, the final purity will decrease. Finally, the optimal point was determined with the conditions of radiation power: 400 watts, radiation time: 1 minute, purity of Fe₃O₄:99.74, and Desirability: 0.99. Also, the optimal point validation test was performed, and its results are presented in Table 1-S.

3.3 Examination of the influence of irradiation time and power in microwave-assisted synthesis

Since in the first stage of the synthesis, the synthesis by power conditions of 400 watts and the irradiation time of 1 minute had a satisfactory result and was free of impurities, the repeatability of this synthesis was investigated, and its results are presented in Table 1-S. Also, considering that by raising the irradiation time of microwave waves during synthesis to more than 1 minute and the irradiance to more than 400 watts, to ensure the effect of power and irradiation time in microwave-assisted synthesis, two syntheses were performed with the conditions presented in Table 2-S. The results of the relevant analysis are presented in Fig. 6. By improving the time and power of microwave radiation, the amount of heat produced during the synthesis process increases, and this issue causes unwanted compounds (NH₄Cl) to dope on the Fe₃O₄ crystallite network. According to the results presented in Fig. 6 and the comparison of the synthesis conditions, it can be seen that the effect of radiation power on microwave-assisted synthesis is more critical than the time of microwave radiation. By increasing the power from 400 to 800 watts, even though the irradiation time is reduced to 30 seconds, NH₄Cl has doped on the Fe₃O₄ nanocatalysts. At a fixed time of one minute, with the increase of power from 400 watts to 600 watts, the presence of NH₄Cl can be seen again. Due to the peak intensity at 2θ = 32.65, Associated with NH₄Cl, It could conclude that the effect of growing the power in creating NH₄Cl and its doped Fe₃O₄ nanocatalysts would be more significant than improving radiation time.

3.4 Effect of electromagnetic radiation on temperature and viscosity deviation

Figure 7-A presented temperature variation under MW radiation (400 watts) with 0.1% wt and without Fe₃O₄ nanocatalysts. The electromagnetic field causes movement in free and bonded charges (electrons and ions) and dipoles, resulting in resistance to induced motion, which will lead to energy loss due to friction, elastic and inertial forces, and heating of materials. During microwave heating, the material's absorption of electromagnetic energy will enhance the sample's temperature. The capability to absorb electromagnetic waves is an essential parameter in raising the efficiency of the electromagnetic heating process [12].

According to Figure 7-A, with the increase in the radiation time of the waves, the temperature of both samples increased because the amount of heat produced during the process raised, which led to an increase in the temperature. Also, increasing the temperature causes cracking heavy componenets and a reduction in the viscosity of the samples. That, in the Figure 7-B, this issue is quite clear. On the other hand, the oil sample containing Fe₃O₄nanocatalysts has a more significant decrease in viscosity than the sample without nanocatalysts. Since Fe₃O₄nanocatalysts are electromagnetic wave absorbers with a high ability to absorb electromagnetic waves and convert them into heat, the viscosity also decreases as the temperature increases.

Furthermore, another experiment was designed and performed to compare the effect of the synthesis method (microwave-assisted and co-precipitation method) on nanocatalyst efficiency in the electromagnetic heating process with microwave waves. It should be mentioned that Fe₃O₄ nanocatalysts were synthesized by the co-precipitation method according to the method presented in [21]. According to Figure 7-B, the highest viscosity reduction was reported in 4 minutes and then the viscosity was rised. Therefore, this time could be the optimum point to check the effect of the type of synthesis method. In 4 minutes and 0.1% wt of nanocatalysts, the effect of the nanocatalyst synthesis method and the presence of waves were investigated.

It should be noted that after 4 minutes of microwave irradiation, the temperature of the crude oil sample, the temperature of the crude oil sample with the Fe₃O₄ nanocatalyst synthesized by the co-precipitation method, and the temperature of the crude oil sample with the Fe₃O₄ nanocatalyst synthesized with microwaves-assisted were 45, 50 and 53°C respectively. That, the amount of weight, loss of the samples due to the increase in temperature was very negligible. The results have been presented in Figure 8. According to Figure 8, the crude oil sample , the crude oil sample containing the nanocatalyst synthesized by the co-precipitation method and the crude oil sample containing the nanocatalyst synthesized with the help of microwaves caused a decrease in viscosity by 11, 23 and 28%, respectively. The nanocatalyst synthesized with the microwave-assisted has caused a more considerable viscosity reduction than the nanocatalyst synthesized by the co-precipitation method, and it is more effective in reducing viscosity and upgrading heavy oil with microwave heating.

This difference could be because the nanocatalysts synthesized with the microwave-assisted have a smaller crystallite size and more prominent absorbing microwaves than the nanocatalysts synthesized by the co-precipitation method. The crystallite size of the nanocatalyst synthesized with the help of microwave waves in this research was 8 nm (Table 2). The crystallite size of the nanocatalyst synthesized by the co-precipitation method was 18 nm. It is the cause of the higher efficiency of these particles in the microwave heating process, increasing the temperature and reducing viscosity.

FTIR analysis was used to investigate the upgrading of heavy oil and changes in its composition. As stated previously, according to Fig. 7-B, the maximum decrease in the viscosity of crude oil samples was reported in 4 minutes. Therefore, in 4 minutes of irradiation of a Microwave, power 400 watt and 0.1% by weight of nanocatalyst Fe₃O₄, the effect of the nanocatalyst synthesis method and the presence of waves on the improvement and composition of the oil was investigated. The results are presented in Fig. 9. With the help of the results of FTIR, the Functional group indexes were investigated in different samples. In this study, these indexes are aromatic, aliphatic, branched alkane and sulfoxide. According to Fig. 9, the mentioned indices were calculated in the crude oil sample, the crude oil sample under wave irradiation, the crude oil sample containing nanocatalyst synthesized by the co-precipitation method under wave irradiation, and the crude oil sample containing nanocatalyst synthesized with the help of microwave waves under wave irradiation. Functional group indexes are calculated from the band area instead of band height because the peak towers are very close to each other. Band area ratio provides the possibility to calculate and compare several types of indicators. These indices were used to determine and compare the chemical composition of each component.

The indicators that have been examined in this research are as follows. Aromatic index (\({A}_{1600}/\sum A\)), Aliphatic index (\({A}_{1376}+{A}_{1460}/\sum A\)), Sulfoxide index (\({A}_{1030}/\sum A\)) and Branched alkane index (\({A}_{1376}/{A}_{1376}+{A}_{1460}\)). During the upgrading process, molecules and heavy compounds of heavy crude oil are cracked, and it is predicted that after the upgrading process, more light compounds and less heavy compounds will be present. According to the results presented in Table 3, it can be concluded that the upgrading process was carried out with the help of microwave waves in the presence of Fe₃O₄ nanocatalyst. According to the above results, the Aliphatic and Branched alkane index have increased and the Aromatic and Sulfoxide index has reduced. For an excellent evaluation of these modifications, the results are presented in Fig. 10.

Table 3- Functional group indexes of oil samples based on FTIR analysis result (*MW :Microwave)

This research examined the synthesis of Fe₃O₄ nanocatalysts using microwaves, the effectual parameters during synthesis and the impact of nanocatalyst on the heavy oil upgrading was investigated. The parameters of power and time of radiation of waves through the amount of heat produced are very effective and affect the synthesis process and the quality of the produced nanocatalysts. The presence of impurities in the crystallite network and the quality of the nanocatalyst were controlled by the power and time of wave radiation. According to the XRD characterization, it could be concluded that with increasing irradiation time of more than 1 minute and microwave radiation power of more than 400 watts, NH₄Cl doped on the Fe₃O₄ nanocatalysts and reduce the purity of nanocatalysts. Because during the microwave synthesis process, the temperature increases with the growth in the power and radiation time of the waves, this increase in temperature causes doping NH₄Cl on the Fe₃O₄ nanocatalysts. It is due mainly to the extensive ionic radius of NH₄⁺ being larger than Fe₃⁺.

Also, according to the electromagnetic properties of nanocatalysts, it was found that these nanocatalysts have the potential to absorb electromagnetic waves. Viscosity changes were investigated under MW radiation (400 W) with 0.1% by weight and without Fe₃O₄ nanocatalysts and over time. By increasing the time of irradiation of waves, the viscosity of both samples decreased because the amount of heat produced during the process increased, leading to an increase in temperature, cracking of heavy component and a decrease in the viscosity of the samples. On the other hand, the oil sample containing Fe₃O₄ nanocatalysts significantly decreases viscosity compared to the sample without nanocatalysts. Since Fe₃O₄ nanocatalysts are electromagnetic wave absorbers with a high ability to absorb electromagnetic waves and convert them into heat. The exhibition of heat and increase in temperature will crack the heavy compounds in the heavy oil and eventually reduce the samples' viscosity. Also, since enough time has been given to the samples to cool down and stabilize the conditions, this decrease in viscosity will be stable.

In addition, the effect of the synthesis method (microwave-assisted method and co-precipitation method) on the efficiency and quality of nanocatalysts in the process of electromagnetic heating with microwave waves was investigated. In 4 minutes and 0.1% by weight of nanocatalysts, the effect of the nanocatalyst synthesis method and the presence of waves were investigated. Fe₃O₄ nanocatalysts synthesized with the microwave-assisted compared to nanocatalysts synthesized by the co-precipitation method have smaller size and caused a significant reduction in viscosity (by 28% and 23%, respectively); thus, these nanocatalysts at heavy oil upgrading are more effective for microwave heating and heavy oil upgrading. This difference could be because nanocatalysts synthesized with the microwave-assisted have a smaller crystallite size and more prominent absorbing microwaves than nanocatalysts synthesized by the co-precipitation method. The smaller crystallite size has increased the efficiency and the ability to absorb waves. On the other hand, by examining the results of FTIR analysis and functional index group, it can be seen that the presence of Fe₃O₄ nanocatalyst causes synergy and increases the efficiency of the microwave heating process, and in addition to reducing the viscosity of oil, it causes further heavy oil upgrading, reducing heavy compounds and increasing light compounds. Without the presence of Fe₃O₄ nanocatalyst and only with the help of microwaves, the aromatic index and sulfoxide index decreased by 3% and 48%, respectively, and the alphabetic index and the branched alkane index increased by 16% and 7%, respectively. As it was presented, the synthesis method of Fe₃O₄ nanocatalyst has an essential effect on their efficiency, and this matter was also confirmed according to the results of the FTIR analysis and the desired indicators. In the presence of microwave waves with a power of 400 watts and a duration of 4 minutes, the Fe₃O₄nanocatalyst synthesized by microwave compared Fe₃O₄nanocatalyst synthesized by co-precipitation has a more significant effect in reducing the aromatic index (13% vs 7%) and the sulfoxide index (90% vs 48%). Also, this condition was seen in the aliphatic and branched alkane indexes.

In the mentioned conditions and in the sample containing Fe₃O₄nanocatalyst synthesized by microwave, the aliphatic index (21% vs 19%) and the alkane branch index (14% vs 8%) increased more. Therefore, nanocatalysts synthesized with the help of microwave waves are more efficient and effective in the process of microwave heating, reducing viscosity and upgrading heavy oil.

DI: Deionized distilled water

API: American Petroleum Institute

EM: Electromagnetic waves

XRD: X-Ray Diffraction

FESEM: Field Emission Scanning Electron Microscope

FTIR: Fourier Transform Infrared

Data availability

The authors declare that, all data generated or analysed during this study are included in this published article [and its supplementary information files].

Declarayion of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

The authors thank Stat-Ease, Minneapolis, MN, USA, for providing the Design-Expert package.

Nguyen MD, Tran HV, Xu S, Lee TR. Fe3O4 nanoparticles: Structures, synthesis, magnetic properties, surface functionalization, and emerging applications. Appl Sci 2021;11. https://doi.org/10.3390/app112311301.
Shixiang Liu, Bing Yu,Song Wang YS. Preparation, Surface Functionalization andApplication of Fe3O4 Magnetic Nanoparticles. 2020. https://doi.org/https://doi.org/10.1016/j.cis.2020.102165.
Zhao F, Liu X, Deng Q. Effect of Nanomagnetite on Properties of Medium- and High-Rank Coals. Nat Resour Res 2021;30:591–603. https://doi.org/10.1007/s11053-020-09724-1.
Ding Y, Zhang L, Liao Q, Zhang G, Liu S, Zhang Y. Electromagnetic wave absorption in reduced graphene oxide functionalized with Fe3O4/Fe nanorings. Nano Res 2016;9:2018–25. https://doi.org/10.1007/s12274-016-1092-z.
Castellanos-Rubio I, Arriortua O, Iglesias-Rojas D, Barón A, Rodrigo I, Marcano L, et al. A Milestone in the Chemical Synthesis of Fe3O4Nanoparticles: Unreported Bulklike Properties Lead to a Remarkable Magnetic Hyperthermia. Chem Mater 2021;33:8693–704. https://doi.org/10.1021/acs.chemmater.1c02654.
K. Winiarczyk, W. Gac MG-K& ZS. Magnetic properties of IRON oxide nanoparticles with a DMSA-modified surface _ Enhanced Reader 2021. https://doi.org/0.1007/s10751-021-01768-w.
Kalantari F, Farahbod F. Mixing of Crude Oil with Organic ZnO Nano-Particles from Rice Bran to Improve Physical Properties of Crude Oil: A Novel Agent for Enhanced Oil Recovery. Nat Resour Res 2019;28:1183–96. https://doi.org/10.1007/s11053-018-9443-y.
Aivazoglou E, Metaxa E, Hristoforou E. Microwave-assisted synthesis of iron oxide nanoparticles in biocompatible organic environment. AIP Adv 2018;8. https://doi.org/10.1063/1.4994057.
Yang ZF, Li LY, Hsieh C Te, Juang RS. Co-precipitation of magnetic Fe3O4 nanoparticles onto carbon nanotubes for removal of copper ions from aqueous solution. J Taiwan Inst Chem Eng 2018;82:56–63. https://doi.org/10.1016/j.jtice.2017.11.009.
Bonfim L, de Queiroz Souza Passos P, de Oliveira Gonçalves K, Courrol LC, de Oliveira Silva FR, Vieira DP. Microwave-mediated synthesis of iron-oxide nanoparticles for use in magnetic levitation cell cultures. Appl Nanosci 2019;9:1707–17. https://doi.org/10.1007/s13204-019-00962-1.
Raveendran S, Sen A, Maekawa T, Kumar DS. Ultra-fast microwave aided synthesis of gold nanocages and structural maneuver studies. Nano Res 2017;10:1078–91. https://doi.org/10.1007/s12274-016-1368-3.
Gharibshahi R, Omidkhah M, Jafari A, Fakhroueian Z. Experimental investigation of nanofluid injection assisted microwave radiation for enhanced heavy oil recovery in a micromodel system. Korean J Chem Eng 2022;39:562–75. https://doi.org/10.1007/s11814-021-0961-7.
Mahmoudi S, Jafari A, Javadian S. Temperature effect on performance of nanoparticle/surfactant flooding in enhanced heavy oil recovery. Pet Sci 2019;16:1387–402. https://doi.org/10.1007/s12182-019-00364-6.
Gharibshahi R, Omidkhah M, Jafari, Arezou, Mehrooz N. Parametric Optimization of In-Situ Heavy Oil Upgrading using simultaneous Microwave Radiation and Magnetic Nanohybrids via Taguchi Approach. Fuel 2022. https://doi.org/doi.org/10.1016/j.fuel.2022.124717.
Yeletsky PM, Zaikina OO, Sosnin GA, Kukushkin RG, Yakovlev VA. Heavy oil cracking in the presence of steam and nanodispersed catalysts based on different metals. Fuel Process Technol 2020;199:106239. https://doi.org/10.1016/j.fuproc.2019.106239.
Nguyen MT, Nguyen DLT, Xia C, Nguyen TB, Shokouhimehr M, Sana SS, et al. Recent advances in asphaltene transformation in heavy oil hydroprocessing: Progress, challenges, and future perspectives. Fuel Process Technol 2021;213:106681. https://doi.org/10.1016/J.FUPROC.2020.106681.
Razavinezhad J, Jafari A, Ghalamizade Elyaderani SM. Experimental investigation of multi-walled carbon nanotubes assisted surfactant/polymer flooding for enhanced oil recovery. J Pet Sci Eng 2022;214:110370. https://doi.org/10.1016/j.petrol.2022.110370.
Chhetri AB, Islam MR. A critical review of electromagnetic heating for enhanced oil recovery. Pet Sci Technol 2008;26:1619–31. https://doi.org/10.1080/10916460701287607.
Vakhin A V., Khelkhal MA, Tajik A, Gafurov MR, Morozov OG, Nasybullin AR, et al. The role of nanodispersed catalysts in microwave application during the development of unconventional hydrocarbon reserves: A review of potential applications. Processes 2021;9:1–20. https://doi.org/10.3390/pr9030420.
Hussain S, Youngs IJ, Ford IJ. The electromagnetic properties of nanoparticle colloids at radio and microwave frequencies. J Phys D Appl Phys 2007;40:5331–7. https://doi.org/10.1088/0022-3727/40/17/048.
Gharibshahi R, Omidkhah M, Jafari A, Fakhroueian Z. Hybridization of superparamagnetic Fe3O4 nanoparticles with MWCNTs and effect of surface modification on electromagnetic heating process efficiency: A microfluidics enhanced oil recovery study. Fuel 2020;282. https://doi.org/10.1016/j.fuel.2020.118603.
Nalbandian L, Patrikiadou E, Zaspalis V, Patrikidou A, Hatzidaki E, N. Papandreou C. Magnetic Nanoparticles in Medical Diagnostic Applications: Synthesis, Characterization and Proteins Conjugation. Curr Nanosci 2015;12:455–68. https://doi.org/10.2174/1573413712666151210230002.
Alterary SS, Alkhamees A. Synthesis, surface modification, and characterization of Fe3O4@SiO2core@shell nanostructure. Green Process Synth 2021;10:384–91. https://doi.org/10.1515/gps-2021-0031.
Miao C, Yang L, Wang Z, Luo W, Li H, Lv P, et al. Lipase immobilization on amino-silane modified superparamagnetic Fe3O4 nanoparticles as biocatalyst for biodiesel production. Fuel 2018;224:774–82. https://doi.org/10.1016/j.fuel.2018.02.149.
Kasparis G, Plan Sangnier A, Wang L, Efstathiou C, LaGrow AP, Sergides A, et al. Zn doped iron oxide nanoparticles with high magnetization and photothermal efficiency for cancer treatment. J Mater Chem B 2022. https://doi.org/10.1039/d2tb01338j.
Marand ZR, Helmi M, Farimani R, Shahtahmasebi N. Study of magnetic and structural and optical properties of Zn doped Fe 3 O 4 nanoparticles synthesized by co-precipitation method for biomedical application Properties of Zn doped Fe 3 O 4 nanoparticles. Nanomed J 2014;1:238–47.
Böttjer T, Stockhausen M. An electron paramagnetic resonance study of Fe3+ ions doped in langbeinites. Phys Status Solidi 1992;174:359–66. https://doi.org/10.1002/pssb.2221740206.
Sun J, Wang W, Yue Q. Review on microwave-matter interaction fundamentals and efficient microwave-associated heating strategies. Materials (Basel) 2016;9. https://doi.org/10.3390/ma9040231.
Xiaokang W, Lyng JG, Brunton NP, Cody L, Jacquier JC, Harrison SM, et al. Monitoring the effect of different microwave extraction parameters on the recovery of polyphenols from shiitake mushrooms: Comparison with hot-water and organic-solvent extractions. Biotechnol Reports 2020;27:e00504. https://doi.org/10.1016/j.btre.2020.e00504.
Liu J, Bin Y, Matsuo M. Magnetic behavior of Zn-doped Fe 3O 4 nanoparticles estimated in terms of crystal domain size. J Phys Chem C 2012;116:134–43. https://doi.org/10.1021/jp207354s.
Ai Z, Deng K, Wan Q, Zhang L, Lee S. Facile microwave-assisted synthesis and magnetic and gas sensing properties of Fe3O4 nanoroses. J Phys Chem C 2010;114:6237–42. https://doi.org/10.1021/jp910514f.

No competing interests reported.

Download PDF

Journal Publication

published 24 Oct, 2023

Read the published version in Scientific Reports →

Editorial decision: Major revision
13 Jul, 2023
Reviews received at journal
10 Jul, 2023
Reviewers agreed at journal
01 Jul, 2023
Reviewers invited by journal
01 Jul, 2023
Editor assigned by journal
01 Jul, 2023
Editor invited by journal
18 Jun, 2023
Submission checks completed at journal
18 Jun, 2023
First submitted to journal
24 May, 2023

You are reading this latest preprint version

Assessment of the synthesis method for purity and particle size of Fe3O4 magnetic nanocatalysts and its effectiveness on viscosity reduction and upgrading of heavy oil

Status:

Journal Publication

Version 1

Abstract

Figures

Highlight

1. Introduction

2. Material and methods

3. Result and discussion

4. Conclusion

Abbreviations

Declarations

References

Additional Declarations

Supplementary Files

Status:

Journal Publication

Version 1