284 © 2025The Author(s). Published by College of Education for Pure Science (Ibn Al-Haitham), University of Baghdad. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License Preparation and Characterization of rGO/Fe3O4/MnO2 Nanocomposite for Enhanced Removal of Terasil Black Dye in Waste Water Treatment Ali Fadhil Ismail 1* and Entisar E. Al-Abodi 2 1,2 Department of Chemistry, College of Education for Pure Science (Ibn Al-Haitham), University of Baghdad, Baghdad, Iraq. *Corresponding Author. Received: 10 December 2024 Accepted: 23 April 2024 Published: 20 July 2025 doi.org/10.30526/38.3.4069 Abstract This study focuses on the synthesis and characterization of a ternary nanocomposite comprising reduced graphene oxide (rGO), magnetite (Fe3O4), and manganese dioxide (MnO2) nanoparticles (NPs). The aim of using it is to remove Terasil Black dye from water, particularly in textile industries. The nanocomposite was created using a co-precipitation method, followed by physical bonding with MnO2 NPs. The structural properties, surface morphology, and elemental composition were evaluated through X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and energy-dispersive X-ray (EDX) analysis. The XRD results confirmed the presence of an amorphous phase along with distinct diffraction peaks that correspond to specific lattice planes. FESEM images showed irregular particle shapes and significant agglomeration. EDX analysis confirmed the presence of the expected elements. The adsorption isotherms displayed (S) patterns as classified by Giles, suggesting that the dye ions align vertically relative to the nanocomposite's surface. The adsorption process is endothermic and primarily driven by physical interactions, which become more significant at higher temperatures. Analyzing the adsorption data indicates that the Freundlich isotherm model better describes this process, suggesting a non-uniform surface. This model demonstrates that chemical and physical adsorption processes were involved, with their contributions varying across different temperature ranges. The findings provide valuable insights into the thermodynamics and kinetics of dye adsorption on rGO/Fe3O4/MnO2 nanocomposites, which are essential for optimizing their application in waste water treatment. Keywords: Adsorption, Manganese oxide nanoparticles, Reduced graphene oxide, Terasil black dye, Waste water. 1. Introduction The adsorbents of waste water obtained through the nanomaterials carbon graphene were applied in the water treatment to solve the water clean-up problem (1). Applying the Hummer method, which involves the preparation of graphene oxide moiety and then inserting the metal nanoparticles (NPs), achieves the desired product (2). Such a novel method, through adsorption phenomena, identifies the centers of the material that increase their number https://orcid.org/0009-0000-2480-2620 mailto:ali.fadel2205p@ihcoedu.uobaghdad.edu.iq https://orcid.org/0009-0004-8637-3939 mailto:entisar.a.l@ihcoedu.uobaghdad.edu.iq https://orcid.org/0009-0000-2480-2620 mailto:ali.fadel2205p@ihcoedu.uobaghdad.edu.iq https://orcid.org/0009-0004-8637-3939 mailto:entisar.a.l@ihcoedu.uobaghdad.edu.iq https://orcid.org/0009-0000-2480-2620 mailto:ali.fadel2205p@ihcoedu.uobaghdad.edu.iq https://orcid.org/0009-0004-8637-3939 mailto:entisar.a.l@ihcoedu.uobaghdad.edu.iq https://orcid.org/0009-0000-2480-2620 mailto:ali.fadel2205p@ihcoedu.uobaghdad.edu.iq https://orcid.org/0009-0004-8637-3939 mailto:entisar.a.l@ihcoedu.uobaghdad.edu.iq https://orcid.org/0009-0000-2480-2620 mailto:ali.fadel2205p@ihcoedu.uobaghdad.edu.iq https://orcid.org/0009-0004-8637-3939 mailto:entisar.a.l@ihcoedu.uobaghdad.edu.iq https://orcid.org/0009-0000-2480-2620 mailto:ali.fadel2205p@ihcoedu.uobaghdad.edu.iq https://orcid.org/0009-0004-8637-3939 mailto:entisar.a.l@ihcoedu.uobaghdad.edu.iq IHJPAS. 2025, 38(3) 285 compared to the conventional adsorbents. The centers of the material approach the contaminants, such as lead or dyes, from water, owing to the advantage of this phenomenon (3). Graphene, considered the thinnest form of the carbon family, is heated weirdly. Furthermore, graphene has unique chemical, mechanical, and electrical properties that it will use to absorb electromagnetic waves faster and thus increase efficiency (4,5).This property makes the graphene array matrices highly viable for many fields and applications involving, among others, strong structures, the environment, energy production, storage, and renewal, because of its exceptional electrical, chemical, and thermal stability, and vast adsorption power along with good transmittance and exceptional specific surface area. These properties make it an outstanding medium for eliminating diverse contaminants (6–8). Also, various methods, namely temperature, microemulsion, and co-precipitation, have been utilized to prepare magnetic NPs (MNPs) (9,10). Regarding molecular recognition and specificity, aptamer-based sensing has clear advantages over established detection methods. However, the ability to synthesize MNPs with a narrow size distribution, specific shape, and surface architecture remains a key limitation of the current technology (11, 12). The exciting field of nanotechnology involves the deliberate fabrication of NPs and the precise control and improvement of their characteristics to enable their numerous applications for scientific development (13–16). The most considerable characteristic is their ability to demonstrate amplified biological bioavailability because of transformations of the most essential parameters, namely size, morphology, and surface area (17). In general, nanoparticle manufacturing heavily utilizes both physical and chemical processes. While the physical approach may reach its boundaries regarding cost-effectiveness, the chemical synthesis requires the direct use of hazardous chemicals that could pose a risk to human health and the environment (18–22).The MnO2 NPs garner considerable attention in research endeavors owing to their broad applicability across multiple domains, facilitated by the capability to manipulate their chemical properties through tailored modifications (23). The advantages of MnO2 NPs stem from their unique properties and versatile applications across various fields. Some key benefits include gas sensing applications (24), biomedical applications, antibacterial properties, catalysis (25), optoelectronic devices, energy storage, photocatalysis, high surface area, and tunable properties (26,27). This study aims to remove Terasil black dye from water, particularly in textile industries. The nanocomposite was created using a co-precipitation method, followed by physical bonding with MnO2 NPs. 2. Materials and Methods 2.1. Materials Reduced graphene oxide (rGO), HCl with a concentration of 37%, FeCl3, FeSO4.7H2O, NaOH, MnO2 NPs, and deionized water were the sources of the chemicals. Merck and Sigma-Aldrich Co. (USA) were the source of all substances. 2.2. Synthesis of rGO/Fe3O4/MnO2 Reduced graphene oxide was synthesized using the modified Hummers’ method (2). In this experimental design, rGO was added as an ingredient of a 200 mL solution containing 0.6 M HCl with a concentration of 37%. This, in addition, was left to agitate for 45 minutes. Afterward, the remaining solution was treated with 28.4 g of FeCl3, and the mixture was vigorously stirred for one hour. The admixture was then grown in the dark for the following hours. At the start of the overnight period, 18.8 g of FeSO4.7H2O were put in the earlier solution, and the mixture was continuously stirred for 60 minutes. After that, 300 mL of 1M sodium hydroxide (NaOH) solution was dropped into the mixture with vigorous stirring at a IHJPAS. 2025, 38(3) 286 temperature of 90°C until the pH reached 11, and it formed black precipitates of the rGO/Fe3O4 sheets. Filtration followed an intensive washing process of the precipitate obtained with deionized water and ethanol. The precipitates were then kept in a drying oven at 90°C with a drying period of five hours (28). The next step was the preparation of 1.25 g of the rGO/Fe3O4 material by dissolving this amount in 125 mL of DI water using sonication to enable diffusion. Afterwards, 1.75 g of MnO2 was precisely weighed and added to the solution that contained the rGO/Fe3O4 composite. The liquid was rigorously shaken for 1 hour to ensure complete uniformization of the chemicals. The filtration procedure was done on the solution after the stirring process to separate the solid parts of the solution. The filtrate supplied was then dried at 80°C for a maximum of 5 hours to remove any remaining moisture in the obtained filtrate. 3. Results and Discussion 3.1. Characterization of rGO/Fe3O4/MnO2 nanocomposite The synthesized samples underwent characterization via X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray (EDX) XRD, FESEM, and EDX techniques. The XRD analysis was employed to investigate the structural properties of rGO/Fe3O4/MnO2 nano powder, while FESEM was utilized to examine surface morphology and nanoparticle size. Additionally, EDX was employed to assess the composition of the samples' elements. The XRD analysis of rGO/Fe3O4/MnO2 nano powder indicates the formation of an amorphous phase. Notably, distinct diffraction peaks were observed at specific 2θ angles, as shown in Table (1) and Figure (1). Table 1. The XRD analysis values of rGO/Fe3O4/MnO2 nanocomposite Pos. (°2Th.) Height (cts) FWHM Left (°2Th.) d-spacing (Å) Rel. Int. (%) Tip Width 23.3110 192.09 0.4920 3.81602 13.13 0.5904 26.6568 710.56 0.2952 3.34416 48.57 0.3542 28.7959 128.01 0.7872 3.10043 8.75 0.9446 33.2046 1462.83 0.3444 2.69816 100.00 0.4133 38.4489 290.16 0.3936 2.34135 19.84 0.4723 42.9526 76.83 0.7872 2.10572 5.25 0.9446 45.3653 164.76 0.5904 1.99918 11.26 0.7085 49.5927 329.86 0.4920 1.83822 22.55 0.5904 55.4561 591.72 0.3444 1.65695 40.45 0.4133 64.3472 119.38 0.3936 1.44781 8.16 0.4723 66.0618 310.29 0.3936 1.41433 21.21 0.4723 Figure 1. The XRD spectra of rGO/Fe3O4/MnO2 nanocomposite Position [°2Theta] (Copper (Cu)) 20 30 40 50 60 70 Counts 0 500 1000 1500 mno2 IHJPAS. 2025, 38(3) 287 During morphological analysis conducted via FESEM, the average value of the dimension of particles equal to 83 nm, it was observed that the surface morphology of the sample revealed particles exhibiting predominantly irregular shapes and significant agglomeration, as depicted in Figure (2). Figure 2. The FESEM images of rGO/Fe3O4/MnO2 nanocomposite The EDX characterization was conducted to determine the elemental composition of the rGO/Fe3O4/MnO2 nanocomposite. The obtained spectra exhibited prominent peaks corresponding to elements, as illustrated in Table (2) and Figure (3). Table 2. The EDX elemental composition of rGO/Fe3O4/MnO2 nanocomposite Element Line Type Apparent Concentration k Ratio Wt% Wt% Sigma Atomic % Standard Label Factory Standard C K series 2.24 0.02245 53.53 0.31 72.43 C Vit Yes O K series 1.67 0.00560 19.30 0.24 19.61 SiO2 Yes Mn K series 1.15 0.01150 12.14 0.21 3.59 Mn Yes Fe K series 1.45 0.01446 15.02 0.25 4.37 Fe Yes Total: 100.00 100.00 Figure 3. The EDX elemental composition of rGO/Fe3O4/MnO2 nanocomposite IHJPAS. 2025, 38(3) 288 3.2. Calibration curve This study prepared a series of standard solutions with known concentrations of Terasil Black dye solutions (10, 20, 40, 60, 80, 100, 120 ppm). By plotting absorbance (A) against concentration (C), a calibration curve is shown in Figure (4), and it has been used to calculate concentration (Ct) at time (t) from the values of the absorbances of Terasil Black dye solution at a wavelength of λ max.= 594 nm, the concentrations of the dye solution were obtained using the Beer-Lambert law: A= ε c l (1) A = Absorbance (unitless). ε = Molar absorptivity (L mol −1 cm −1) , a constant specific to the substance. c = Concentration of the solute (mol/L). l = Path length of the cuvette (cm). Figure 4. Calibration curve of Terasil Black at different concentrations 3.3. Contact time The study investigated the time required for the adsorption process to attain equilibrium. That was done by utilizing a 100 ppm of Terasil Black dye, a temperature of 293K, a pH of 7, and an adsorbent dose of 0.025 g. Various contact periods were examined. Figure (5) illustrates the graph of (qt) plotted against time (t), and by using the equation: qt = (Co-Ct) (2) Where the values of qt, Co, Ct, V, and m represent the amount of the adsorbate (mg/g) at time (t), the initial aqueous concentration (ppm), the concentration (ppm) at time (t), the solution volume (L), and the adsorbent weight (m), respectively. The contact periods indicate that the adsorption capacity of the dye increases as the contact time increases. Initially, the adsorption process occurred rapidly due to the abundance of binding sites present on the surfaces of the adsorbents. However, most of these sites would become occupied over time, reducing adsorption effectiveness. Depending on the scarcity of available active sites on the surface of the adsorbent, only a minimal quantity of dye may adhere. Once all the binding sites for the dye ions have been exhausted, the adsorbents reach a state of saturation and maintain a constant adsorption capacity. The equilibrium time of Terasil Black dye solution on rGO/Fe3O4/MnO2 nanocomposite surface is 60 minutes, as shown in Figure (5). y = 0.0012x + 0.0075 R² = 0.9981 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0 20 40 60 80 100 120 140 A b s. Con.(ppm) IHJPAS. 2025, 38(3) 289 Figure 5. The contact time of Terasil Black on rGO/Fe3O4/MnO2 nanocomposite surface at 293 K 3.4. Effect of change in temperature The adsorption of Terasil Black dye from an aqueous solution was studied on the surfaces of rGO/Fe3O4/MnO2 nanocomposites. A 250 mL of dye solution with varying concentrations was used, keeping other parameters such as pH= 7 and adsorbent dose (0.025 g) constant. The flask containing the solutions was placed in a shaker controlled by a thermostat, set at a speed of 100 cycles per minute. This was done for an equilibrium period of around 60 minutes, at temperatures of 288, 298, 308, and 318 Kelvin, specifically for the surface of the rGO/Fe3O4/MnO2 nanocomposite. The adsorption quantities (qe, Ce) were recorded in Table (3) and Figure (6). These values were determined using the equation: qe = (Co-Ce) V/m (3) The values of qe, Co, Ce, V, and m represent the amount of the adsorbate, the initial aqueous concentration, the equilibrium concentration, the solution volume, and the adsorbent weight, respectively. Adsorption isotherms provide essential knowledge about the adsorption process, including its circumstances, the adsorbed material's adsorption capability, and the concentration at which it occurs. It has been observed that the adsorption isotherm of Terasil Black dye on the surface of rGO/Fe3O4/MnO2 nanocomposite follows the (S1) type according to the (Giles) classification, as in Figure (6). The S-type isotherm is derived from Freundlich's fundamental adsorption principles. Heterogeneous surfaces result in this form of isotherm, where adsorption occurs with varying forces over various surface regions. The adsorption energy decreases as the surface coverage increases, as may be deduced during class (S), it was discussed that the orientation of adsorbed molecules on a surface might be perpendicular, meaning they were connected from one end. This vertical orientation allows the molecules to occupy less surface area, resulting in a higher adsorption rate. Giles showed that the S class of isotherms represents non-chemical adsorption, indicating the existence of dispersion forces or hydrogen bonding. The activation energy provides insight into the likelihood of interactions. If the interaction forces between the adsorbent and the adsorbate were significant, the activation energy will be elevated, resulting in adsorption following the class (S) or the Freundlich isotherm. This implies that the adsorbent molecules arrange themselves in rows or clusters on the surface. This is supported by the isotherm shape, in which adsorption rises proportionally with the increase in equilibrium concentration. 0 10 20 30 40 50 60 0 20 40 60 80 100 120 140 q t (m g /g ) Time (min.) IHJPAS. 2025, 38(3) 290 Table 3. The quantity of the adsorbate and the equilibrium concentration of Terasil Black on rGO/Fe3O4/MnO2 nanocomposite surface at four different temperatures 288 Kelvin 298 Kelvin 308 Kelvin 318 Kelvin Co Ce(mg/L) qe(mg/g) Ce(mg/L) qe(mg/g) Ce(mg/L) qe(mg/g) Ce(mg/L) qe(mg/g) 50 32.08333 17.91667 31.25 18.75 30.41667 19.58333 19.58333 30.41667 100 55.41667 44.58333 49.58333 50.41667 42.08333 57.91667 37.91667 62.08333 150 62.08333 87.91667 57.08333 92.91667 54.58333 95.41667 44.58333 105.4167 200 67.08333 132.9167 56.25 143.75 52.08333 147.9167 42.91667 157.0833 250 81.25 168.75 65.41667 184.5833 62.91667 187.0833 57.08333 192.9167 300 95.41667 204.5833 82.08333 217.9167 77.08333 222.9167 71.25 228.75 Figure 6. The adsorption isotherms of Terasil Black on rGO/Fe3O4/MnO2 nanocomposite surface at four different temperatures It has been observed that the amount of adsorbed material from the Terasil Black dye on the surface of the rGO/Fe3O4/MnO2 nanocomposite increased when the dye concentration was increased. As the concentration increased, more dye molecules with positive charges showed up. This increased the electrostatic attraction between the dye molecules and the active sites on the surface, improving adsorption. On the other hand, as the temperature rises, we observe an increase in the quantity of material adsorbed. Higher temperatures provide the required activation energy for the dye ions to surpass the energy barrier needed for adsorption. This signifies the endothermic characteristic of the adsorption process and the presence of an absorption process alongside the adsorption process. As the temperature rises, the rate at which the dye molecules spread on both the surface and within increases. The adsorbent surface's holes facilitate the adsorption of Terasil Black dye on all surfaces, particularly at elevated temperatures. 3.5. Adsorption isotherms The study focused on examining the adsorption isotherms of Terasil Black dye on the surfaces of rGO/Fe3O4/MnO2 nanocomposites, which were used as adsorbents. Several models, such as the Freundlich, Langmuir, and Temkin models, may be used to explain the experimental data. 3.5.1. Freundlich model The Freundlich isotherm is used to investigate the process of multilayer adsorption. This isotherm is derived from the process of adsorption in heterogeneous systems, and it is represented in the following manner (29): qe = KF Ce 1/n (4) Where qe is the adsorption capacity (mg/g) and KF is the Freundlich constant (L/g). Figure (7) depicts the linear Freundlich equation graphically, where lnqe is plotted against lnCe, 0 50 100 150 200 250 0 20 40 60 80 100 120 q e( m g /g ) Ce(mg/L) 288 K 298 K 308 K 318 K IHJPAS. 2025, 38(3) 291 resulting in a straight line. The intercept of the line is lnKF, while the slope represents (1/n). KF (L/g) denotes the adsorbed capacity, whereas n represents the adsorption intensity. Figure 7. Linear Freundlich adsorption isotherm of Terasil Black on rGO/Fe3O4/MnO2 nanocomposite surface at four different temperatures Considering the data shown in Table (4), it is evident that the variable (n) consistently increases. This parameter quantifies the adhesive strength between the surface of the rGO/Fe3O4/MnO2 nanocomposite and other substances at various temperatures. Table 4. Freundlich constants and correlation coefficient for the adsorption of Terasil Black on rGO/Fe3O4/MnO2 nanocomposite surface at four different temperatures 288 Kelvin 298 Kelvin 308 Kelvin 318 Kelvin KF 0.004374 0.001483 0.002268 0.213227 n 0.419252 0.363557 0.370041 0.603828 R 2 0.9464 0.9666 0.9885 0.9767 The observed rise indicates that the Terasil black dye is being physically adsorbed onto the surface of the nanocomposite. The KF value of Terasil Black dye adhering to the surface of the rGO/Fe3O4/MnO2 nanocomposite increases as the temperature increases, indicating that the adhesion mechanism is endothermic. Based on the correlation coefficient values (R 2 ) for the Freundlich model, it has been concluded that the Freundlich equation applies to the surface being studied. Nevertheless, its efficacy diminishes with rising temperatures. This indicates that adsorption processes occur on surfaces with diverse properties, resulting in many sites with variable levels of adsorption energy. 3.5.2. Langmuir isotherm model The isotherm described specifically applies to adsorbent molecules that selectively bind to unoccupied sites on the surfaces of the adsorbent substances. Each site can accommodate just one atomic or molecular adsorbent species (30). The equation can be written as follows: (5) The qmax value represents the highest adsorption capacity in (mg/g). In contrast, KL refers to the Langmuir constant, which is associated with the affinity binding sites and energy of adsorption, (L/mg). The graphical representation of linear Langmuir equation in Figure (8) shows a plot of Ce/qe vs Ce obtains in a straight line has an intercept equal to (1/KL qmax) and a value of a slope is (1/qmax). 0 1 2 3 4 5 6 2.5 3 3.5 4 4.5 5 ln q e ln Ce 288 K 298 K 308 K 318 K IHJPAS. 2025, 38(3) 292 Figure 8. Linear Langmuir adsorption isotherm of Terasil Black on rGO/Fe3O4/MnO2 nanocomposite surface at four different temperatures The data in Table (5) shows the value of adsorbed Terasil Black on rGO/Fe3O4/MnO2 nanocomposite surface at different temperatures. The above values show that the adsorption process obeys the Langmuir isotherm less than the Freundlich isotherm. The adsorption at maximum capacity (qmax) increased when the temperature increased, indicating that the adsorption density is enhanced at high temperatures. Moreover, the result shows that adsorption energy (KL) increased when the temperature increased, which reveals a higher affinity between the above surface and Terasil Black dye. Table 5. Langmuir constants and correlation coefficient for the adsorption of Terasil Black on rGO/Fe3O4/MnO2 nanocomposite surface at four different temperatures 288 Kelvin 298 Kelvin 308 Kelvin 318 Kelvin qmax -45.045 -37.594 -41.6667 -138.889 KL -0.00957 -0.01183 -0.01246 -0.00952 R 2 0.8065 0.7757 0.6845 0.5956 3.5.3 Temkin isotherm model This model assumes a linear decrease in the synchronous temperature of the adsorption process for the molecules in the layer when the surface is covered due to interactions between the surface molecules and the adsorbent (31). The isotherm of Temkin is represented by the equation (6): qe= B ln (AT .Ce) (6) Where B is the isotherm of Temkin constant, which is determined as follows: B = RT/b, R is the constant of the gas (8.314 J/K.mol), T is the temperature at the absolute state and b is the heat of adsorption (J/mol), AT is the equilibrium binding constant representing the maximum binding energy (L/g). The graphical representation of the linear Temkin equation in Figure (9) shows a plot of qe vs ln Ce obtained in a straight line, with an intercept equal to (AT) and a slope equal to (BT). From the results in Figure (9), it was concluded that there was a good fit and reasonable accuracy; however, the calibration curve deviated slightly from the experimental data. The most suitable temperature was 308 Kelvin, as indicated by a coefficient of determination (R²) of 0.8945. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 20 40 60 80 100 120 C e/ q e (L /g ) Ce(mg/L) 288 K 298 K 308 K 318 K IHJPAS. 2025, 38(3) 293 Figure 9. linear Temkin adsorption isotherm of Terasil Black on rGO/Fe3O4/MnO2 nanocomposite surface at four different temperatures Considering the data in Table (6), it can be concluded that the low values of the heat of adsorption (BT) and the increase of Temkin isotherm constants (AT) with rising temperature indicate a preference for adsorption at high temperatures. This suggests that the system is suitable for physical adsorption and endothermic processes. Table 6. Temkin constants and correlation coefficient for the adsorption Terasil Black on rGO/Fe3O4/MnO2 nanocomposite surface at four different temperatures 288 Kelvin 298 Kelvin 308 Kelvin 318 Kelvin BT 177.65 218.83 227.83 158.37 AT 0.02981 0.031371 0.033453 0.053456 R 2 0.8585 0.8777 0.8945 0.8887 4. Conclusion The adsorption isotherms of Terasil Black on the surface of rGO/Fe3O4/MnO2 nanocomposite adsorbent exhibit an S-shaped pattern at various temperatures, as classified by Giles. This suggests that the dye ions were packed within clusters or rows on the adsorbent surface, aligned vertically, for the rGO/Fe3O4/MnO2 nanocomposite. The adsorption of Terasil Black dye on the surfaces of rGO/Fe3O4/MnO2 nanocomposites is primarily controlled by an endothermic and physical adsorption mechanism, which is intensified at elevated temperatures. The process exhibits a stronger adherence to the Freundlich isotherm, indicating that the adsorption process occurred on non-homogeneous surfaces. Both chemical and physical adsorption processes were involved at various temperature ranges. Acknowledgment The authors thank the Department of Chemistry at the College of Education for Pure Science (Ibn Al-Haitham) at the University of Baghdad, for providing chemicals and support. Conflict of Interest The authors declare that they have no conflicts of interest. Funding No funding. Ethical Clearance This work has been approved by the Scientific Committee at the Department of -50 0 50 100 150 200 250 2.5 3 3.5 4 4.5 5 q e( m g /g ) lnCe 288 K 298 K 308 K 308 K IHJPAS. 2025, 38(3) 294 Chemistry, College of Education for Pure Science (Ibn Al-Haitham), University of Baghdad. References 1. Sadiq YM, Al-Abodi EE. 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