Employing a magnetic chitosan/molybdenum disulfide nanocomposite for efficiently removing polycyclic aromatic hydrocarbons from milk samples

This study aimed to develop a highly efficient nanocomposite composed of magnetic chitosan/molybdenum disulfide (CS/MoS2/Fe3O4) for the removal of three polycyclic aromatic hydrocarbons (PAHs)—pyrene, anthracene, and phenanthrene. Novelty was introduced through the innovative synthesis procedure and the utilization of magnetic properties for enhanced adsorption capabilities. Additionally, the greenness of chitosan as a sorbent component was emphasized, highlighting its biodegradability and low environmental impact compared to traditional sorbents. Factors influencing PAH adsorption, such as nanocomposite dosage, initial PAH concentration, pH, and contact time, were systematically investigated and optimized. The results revealed that optimal removal efficiencies were attained at an initial PAH concentration of 150 mg/L, a sorbent dose of 0.045 g, pH 6.0, and a contact time of 150 min. The pseudo-second-order kinetic model exhibited superior fitting to the experimental data, indicating an equilibrium time of approximately 150 min. Moreover, the equilibrium adsorption process followed the Freundlich isotherm model, with kf and n values exceeding 7.91 mg/g and 1.20, respectively. Remarkably, the maximum absorption capacities for phenanthrene, anthracene, and pyrene on the sorbent were determined as 217 mg/g, 204 mg/g, and 222 mg/g, respectively. These findings underscore the significant potential of the CS/MoS2/Fe3O4 nanocomposite for efficiently removing PAHs from milk and other dairy products, thereby contributing to improved food safety and public health.


Materials
Chitosan with a low molecular weight and a degree of deacetylation of 80%, molybdenum trioxide, urea, thioacetamide, and ethanol were obtained from Sigma-Aldrich (St Louis, MO, USA).glutaraldehyde (a 50% solution in distilled water), sodium triphenylphosphine (TPP), glacial acetic acid (98% purity), ammonium hydroxide, manganese chloride tetrahydrate, hydrochloric acid (37% v/v), and sodium hydroxide were purchased from Merck (Darmstadt, Germany).Magnetic Fe 3 O 4 were purchased from US Research Nanomaterials, Inc. PAH standards, including pyrene (PYR), phenanthrene (PHEN), and anthracene (ANTH), were obtained from Aldrich (Milwaukee, WI, USA).To prepare the standard solution for each PAH, HPLC-grade methanol was utilized to create a stock solution of each PAH (500 mg/L), and raw milk sampling was purchased from markets (Neyshabur, Iran).

Preparation of MoS 2 nanoparticles
A precise mixture of urea (8.00 g), MoO 3 (0.96 g), and thioacetamide (1.123 g) was carefully poured into deionized water (80 mL), ensuring thorough mixing by employing magnetic stirring for 1 h to achieve a uniform solution.Afterward, the solution was moved to an autoclave and exposed to 200 °C for 12 h.After the completion of the heating process, the autoclave was allowed to cool gradually to reach the ambient temperature of 25 °C.The resulting product was then meticulously rinsed with deionized water and ethanol, respectively.Finally, MoS 2 nanosheets as the product was dried for 12 h at 60 °C to ensure complete removal of moisture 32 .

Cs/MoS 2 /Fe 3 O 4 nanocomposite preparation
The synthesis of the hybrid nanocomposite, comprising chitosan and MoS 2 , involved a two-step process.Initially, a chitosan solution with a concentration of 0.2% w/v was prepared by dissolving chitosan (0.1 g) in a CH 3 COOH solution (50 mL, 1% v/v) under magnetic stirring at 25 °C.Then, the MoS 2 nanosheets were poured into the chitosan solution and subjected to sonicate for 5 h to achieve a MoS 2 -dispersed chitosan matrix with a weight/ volume ratio of 0.1:0.2%.The resulting mixture was centrifuged at 6000 rpm for 15 min to separate the solution.
In the subsequent step, 20 mg of Fe 3 O 4 nanoparticles were introduced into the MoS 2 -dispersed chitosan solution and mechanically stirred for 2 h at 25 °C.A combination of 10 mL of paraffin and 4 mL of Span-80 emulsifier was

Characterization
To analyze the structure of the magnetics Cs/MoS 2 /Fe 3 O 4 nanocomposite, various instruments were employed.The functional groups of the nanocomposite were examined using a Bruker Vertor-22 FTIR instrument from Germany.The dispersibility and size of the prepared nanocomposite were observed through Transmission Electron Microscopy (EM Philips EM 208S).The XRD pattern of the sorbent was obtained using a Rigaku-12 KW X-ray diffractometer.The magnetic properties of the sorbent were investigated using a vibrating sample magnetometer from Lake Shore Cryotronics in the USA.Additionally, Field Emission-Scanning Electron Microscopy (MIRA3 TESCAN, Czech Republic) was utilized to study the morphology of the sorbent.The analysis of PAHs was conducted using the Agilent GC/MS system (Model: 7890B, USA) following a previously established method 37 .Helium gas (99.99% purity) as the carrier gas with a flow rate of 1.8 mL/min was selected.The temperature program involved three steps.Firstly, it was set at 70 °C and then increased to 250 °C at a rate of 15 °C/min.Subsequently, it was further increased to 315 °C at a rate of 5 °C/min, and held at this temperature for 5 min.The MS was operated in full scan mode with an ion source temperature of 270 °C.It scanned a range of 50 to 320 m/z and utilized an ionization energy of 70 eV.

Adsorption study
The magnetic Chitosan/MoS 2 nanocomposite as a sorbent was used for removing PAHs in batch adsorption experiments.These experiments were performed using an Erlenmeyer flask (50 mL), and various operational parameters were investigated.The initial concentration of PAHs was 150 mg/L, and the dosage of the nanocomposite and the pH ranged from 0.01 to 0.06 g and 5.0 to 8.0 using NaOH or HCl aqueous solution with a concentration of 0.1 M, respectively.The contact time was fixed at range of 10 to 160 min, and the experiments were conducted at room temperature.To prepare the samples, a milk sample of 25.0 mL was spiked with a standard solution of PAHs, resulting in a final PAH concentration of 150 mg/L.Then, 0.04 g of the magnetic Chitosan/MoS 2 nanocomposite was added to the spiked milk sample.The adsorption process took place at room temperature with continuous shaking at 150 rpm for 150 min.After completing the adsorption of PAHs, the sorbent was completely separated from the spiked milk sample solution using a magnet.The solution (1 µL) was injected into GC/MS for further analysis.The adsorption capacity (q e ) and removal percentage (R%) of the PAH removal from the spiked milk sample solution were determined by the following equations: Here, C e and C i represent the final and initial concentrations of PAHs (mg/L), respectively, while V denotes the milk sample volume (mL), and M indicates the sorbent mass (g) 20,22,38,39 .

Adsorption isotherms
In the experiments on adsorption isotherms, a quantity of sorbent (0.04 g) alongside a 25.0 mL of spiked milk sample containing PAHs at concentrations ranging from 20 to 150 mg/L.The mixture was shaken at 200 rpm for 3h.The adsorption data underwent adjustments through the utilization of Langmuir, Freundlich, Sips, and Dubinin-Adushkevich models 40 .

Adsorption kinetics
The kinetic study was carried out using a spiked PAH solution (25.0 mL) with a concentration of 100 mg/L, and 0.04 g of sorbent.The experiments were conducted in a shaker operating at 200 rpm, maintaining a temperature of 25 ± 1 °C.Later, 20 µL of milk sample was extracted from the supernatant for each analysis over a total duration of 150 min.The rate constants for the adsorption of PAHs were determined by fitting the experimental data to the pseudo-second order and pseudo-first order models 40 .

Ethics statement
The authors confirm they did not disturb dairy cows in any way, and raw milk sampling was purchased from markets (Neyshabur, Iran).We declare that all methods were carried out in accordance with relevant guidelines and regulations.The method of this study has been approved by the Ethics Committee of Neyshabur University of Medical Sciences (IR.NUMS.REC.1401.001).

FTIR analysis
FTIR spectra were utilized to assess the chemical structures and functional groups of the sorbent.The FTIR spectrum of Fe 3 O 4 (Fig. 1Aa) displayed peaks at 3439 cm −1 and 584 cm −1 , which corresponded to the stretching (2) q e = (C i − C e ) * V M vibration of free hydroxyl groups and Fe-O bonds, respectively 41,42 .On the other hand, the CS spectrum (Fig. 1Ab) showed a broad peak ranging from 3200-3550 cm −1 , which was attributed to the stretching vibration of hydroxyl groups 43 .Additionally, the presence of −CH 2 − vibration is shown at 2872 and 2941 cm −1 , while the peak at 1653 cm −1 indicated the presence of the stretching vibration of C-O groups [43][44][45] .The FTIR spectrum of the produced MoS 2 is presented in Fig. 1Ac, indicating specific peaks at 639, 893, 1402, and 1622 cm −1 .Furthermore, the peaks at 931 and 3182 cm −1 were related to the S-S bond and the broad stretching band of the O-H group, respectively 46 .It is worth noting that the characteristic stretching band of C=O presented in the amide group shifted towards a lower wavenumber, potentially because of the electrostatic interaction between the negative charge on the surface of MoS 2 and positive charge of CS 46 .Lastly, in the FTIR spectrum of the Cs/MoS 2 /Fe 3 O 4 nanocomposite pattern (Fig. 1Ad), the peak at 1599 cm -1 was attributed to the deformation vibration of the amine groups in CS.Additionally, the wide peak at 3423 cm -1 was formed by the stretching vibration of hydroxyls in Fe 3 O 4 and CS 46,47 .These observed peaks collectively indicate the successful combination of Fe 3 O 4 , CS, and MoS 2 .

XRD analysis
The XRD pattern was used to examine the crystalline structure of the produced adsorbent.In the case of CS, several peaks were observed at 2θ = 15.6°,17.4°, and 21.8°, which are indicative of a semi-crystalline polymer.The peak at 2θ = 19.97°corresponds to the crystalline chitosan framework, confirming the presence of biopolymer backbone chains 47 .These XRD results are consistent with previous findings on CS diffraction patterns 48 .

TEM and FE-SEM studies
The nanocomposite's morphology and size were analyzed using TEM.In Fig. 2A, a typical TEM image illustrates the well-dispersed Fe 3 O 4 particles with an average diameter of approximately 10-12 nm, as clearly shown in the inset of Fig. 3. Upon combining with MoS 2 , a distinct uniform core-shell structure is observed (Fig. 2A), where crumpled few-layer MoS 2 nanosheets form a thin shell around the Fe 3 O 4 , with a length of about 199 nm.The layered structure of MoS 2 is evident, with individual layers discernible in bright and darker sections from the layer cross-section 51 .At higher magnification, the TEM reveals that some Fe 3 O 4 and CS are bound to the surface of the MoS 2 nanosheets.Additionally, the nanocomposite's morphology and surface uniformity were examined using FE-SEM images.As depicted in Fig. 4, the FE-SEM images show the flake-like MoS 2 structure deposited on Fe 3 O 4 nanoparticles in the synthesized nanocomposite.Furthermore, Fig. 2b 2d.This pattern reveals that the composite material consists of carbon, oxygen, iron, sulfur, nitrogen and molybdian elements, with weight percentages of 15.24%, 34.31%, 49.69%, 0.38%, 0.06% and 0.32%, respectively.Notably, carbon and molybdian exhibit the highest and lowest weight percentages within the sorbent structure.

VSM analysis
The magnetic properties of the CS/MoS 2 /Fe 3 O = nanocomposite were analyzed using hysteresis curves obtained through VSM, which revealed zero coercivity and remanence, indicating the nanocomposite has the super-magnetism property.As illustrated in Fig. 2C, Fe 3 O 4 displayed a high degree of magnetization (~ 50 emu/g).Besides, the magnetization value considerably decreased to around 18 emu/g upon coating Fe 3 O 4 with CS/MoS 2 (Fig. 2C).This phenomenon can be attributed to the presence of additional materials in the nanocomposite, which can alter the magnetic properties of Fe 3 O 4 35 .It is worth noting that magnetic nanocomposites have potential applications as adsorbents for removing toxic agents from aqueous solutions due to their high surface-to-volume ratio, water repellency, fast diffusion, and super-magnetism 51,52 .

Effect of Cs/MoS 2 /Fe 3 O 4 nanocomposite dose
Determining the optimal dosage of Cs/MoS 2 /Fe 3 O 4 nanocomposite for achieving maximum adsorption of PAHs is a crucial factor in adsorption studies 53,54 .In this study, the impact of varying dosages of Cs/MoS 2 /Fe 3 O 4 nanocomposite ranging from 0.01 to 0.05 g on the adsorption of PAHs (phenanthrene, anthracene, and pyrene) was extensively investigated and analyzed (refer to Fig. 3A).The results revealed a significant trend, where the adsorption efficiencies of the PAHs increased with increasing dosage of the nanocomposite from 0.01 to 0.045 g, eventually reaching a plateau.This behavior can be attributed to the availability of active sites on the surface of the sorbent that play a crucial role in the interaction with the PAHs.Thus, an increase in the sorbent dosage led to a corresponding increase in the removal of PAHs due to an enhanced number of active sites available for the adsorption process.These findings are consistent with the results reported by Zhou et al. in their investigation of the impact of nanocomposite dosage on the maximum adsorption of PAHs 55 .Therefore, based on these collective findings, a sorbent dosage of 0.045 g was selected for further detailed investigation and analysis in subsequent experiments.

Effect of solution pH
The pH is an important parameter to consider when studying liquid-phase adsorption 55 .Figure 3B depicts the adsorption of phenanthrene, anthracene, and pyrene from milk samples using Cs/MoS 2 /Fe 3 O 4 nanocomposite at various pH values ranging from 5 to 8. The adsorption percentage of these PAHs increased within the pH range of 3 to 6 but decreased afterward.This can be attributed to the favorable interaction between the aromatic rings of the PAHs and the ion-pair of amines or hydroxyl groups in chitosan, which is present in the sorbent and aids in PAH removal.At low pH levels, chitosan in the sorbent dissolved in the solution, resulting in the protonation of its amine groups.As a consequence, the negative charge on the sorbent surface decreased, limiting its interaction with the delocalized π electrons in the aromatic rings of PAHs.Conversely, at high pH levels, hydroxide ions in the solution competed with the sorbent for interaction with PAHs.This competition reduced the adsorption of PAHs on the sorbent's surface.

Effect of initial PAH concentration
The efficiency of PAH removal was evaluated using the synthesized nanocomposite at different concentrations (ranging from 50 to 175 mg/L), and the results are depicted in Fig. 3C.The highest removal efficiency was observed when the PAH concentration was at 150 mg/L.This finding can be attributed to the relationship between the PAH concentration and the number of active sites available on the surface of the nanocomposite 56 .When the number of active sites on the sorbent surface becomes saturated with PAHs, they are no longer adsorbed.Thus, as long as there are active sites available, there is potential for interaction with PAHs.Consequently, the removal of PAHs increased as the PAH concentration increased up to 150 mg/L and then decreased thereafter.Therefore, a PAH concentration of 150 mg/L was chosen as the optimal value for further investigation.

Effect of contact time
The duration of contact between PAHs and the sorbent is a crucial factor that influences the efficiency of adsorption 57 .Contact time refers to the minimum duration required to achieve a consistent concentration, known as the adsorption equilibrium stage.Once this equilibrium is reached, the concentration of PAHs in the solution remains stable because the amount of PAHs absorbed on the sorbent's surface equals the amount desorbed into the sample solution.In this study, the influence of contact time on the adsorption efficiency of PAHs was examined at room temperature over various durations (ranging from 10 to 160 min).As shown in Fig. 3D, the adsorption of PAHs increased up to 150 min and then remained constant with further increases in time.This suggests that PAHs reached equilibrium on the sorbent's surface after 150 min.Therefore, a contact time of 150 min was chosen as the optimal value for further investigation.

Adsorption isotherms and kinetic study
In order to assess the efficiency of the sorbent's adsorption, we examined the equilibrium adsorption values of phenanthrene, anthracene, and pyrene within the concentration range of 20 to 150 mg/L on the sorbent (0.045 g) using the Langmuir and Freundlich models.The Langmuir (Eq.3), Freundlich (Eq.4), Sips (Eq.5), and Dubinin-Adushkevich (Eqs.6 and 7) isotherm models can be represented by the following equations 21,58 : Here, C e and q e represent the initial concentration of phenanthrene, anthracene, and pyrene (mg/L) spiked in milk samples, and the equilibrium absorption amount of the sorbent (mg/g), respectively.Besides, n, k f , b, and q max denote the adsorption intensity, Freundlich constants (mg/g), Langmuir constant (L/mg), and maximum monolayer adsorption capacity (mg/g), respectively.Besides, K s , q MS and β present equilibrium constant (L/mg), maximum adsorption capacity(mg/g), and model exponent of the Sips.K DR (mol 2 /kJ), q mDR (mg/g), and ε denote the adsorption energy constant, capacity of saturation theory, and potential Polanyi, respectively.Also, ε calculates using Eq. ( 8).The regression coefficient (R 2 ) obtained for each graph was utilized to select the appropriate isotherm model.Based on the results in Table 1, the R 2 values obtained from the Langmuir and Dubinin-Adushkevich equations were lower than those from the Freundlich and Sips equations for the adsorption of PAHs, showing that the Freundlich and Sips models effectively describes the absorption of these compounds.These findings align with the results presented in the TEM and FE-SEM images of Cs/MoS 2 /Fe 3 O 4 nanocomposite as the sorbent (Fig. 2A, B), which demonstrate heterogeneity on the sorbent surface.The desirability of the adsorption process was evaluated using the adsorption intensity (n).Suitable absorption of PAHs on the sorbent occurs when the n-value falls between 1 and 10.The n-values of 1.49, 1.20, and 1.20 from the Freundlich equation for the adsorption of pyrene, anthracene, and phenanthrene, respectively, confirm that their adsorption on the produced nanocomposites is satisfactory.Additionally, the K F values exceeding 8.03 obtained for the adsorption of PAHs indicate a high affinity for their adsorption process on the sorbent surface.Besides, a high value of β (β > 1) for the adsorption of PAHs in the sorbent obtained from Sips model indicated that interactions between PAHs and the sorbent were took place.Also, these interactions are strong because K s are high.The maximum adsorption capacity (q mS ) of the sorbent is in the range of 83.456 -83.709 mg/g for removing PAHs.The Langmuir equation slope was utilized to calculate the maximum adsorption capacity (q max ) of Cs/MoS 2 /Fe 3 O 4 nanocomposite to adsorb PAHs.The maximum absorption capacity to adsorb phenanthrene, anthracene, and pyrene on the produced nanocomposites was 217, 204, and 222 mg/g, respectively.The utilization of the newly created nanocomposite as a sorbent for eliminating PAHs comes with several benefits, one of which is its elevated surface-to-volume ratio.As a result, only a small quantity of sorbent is necessary, and optimal conditions lead to high adsorption capacity and suitable interaction with PAHs 59 .To analyze the kinetics of the adsorption process and fit the adsorption data over time, different kinetic models have been employed, such as the pseudo-first-order (Eq.8), pseudo-second-order (Eq.9) and intra-particle diffusion kinetic (Eq.10) models.The linear forms of these model equations used in the kinetic study are outlined below 22,60,61 : These equations involve the variables q e (mg/g), q t (mg/g), and k, representing the amount of adsorbed PAHs at equilibrium time and at time t (min), and the rate constant, respectively.The impact of adsorption time was examined to assess and determine the appropriate kinetic models for the elimination of PAHs using the newly developed nanocomposites.The results for PAH removal are illustrated in Fig. 5. Generally, the adsorption of PAHs adheres to a pseudo-second-order kinetic model, as indicated by higher correlation coefficient values compared to other kinetic models.The q e values and rate constants for adsorbing PAH were obtained from the equation and presented in Table 2.Moreover, the findings demonstrate that the removal percentage (R%) increases until approximately 150 min of adsorption time.This suggests that the removal process is rapid with an equilibrium time under 150 min for PAHs.The outcomes can be attributed to the effective removal process facilitated by the interaction between functional groups on the sorbent surface and those in PAHs 21 .Additionally, the diffusion of metal ions into the sorbent pores is significantly reduced.The low correlation coefficient values for the intra-particle diffusion model further confirm that PAH adsorption occurs through physical or chemical interactions between the sorbent and PAHs.Notably, the penetration of PAHs into the sorbent pores is minimal.(8)  log q e − q t = logq e − k 1 t 2.303 (9)

The sorbent reusability
The reusability of sorbents holds significant importance for several reasons.Firstly, it mitigates costs associated with disposal and replacement, rendering the remediation process economically viable, particularly for large-scale endeavors.Secondly, it curtails waste production, thereby promoting environmental preservation and sustainability.Thirdly, it amplifies the efficiency of PAH removal by optimizing the utilization of sorbent material across multiple cycles, thereby enhancing overall remediation efficacy.Consequently, the reusability of magnetic chitosan/MoS 2 nanocomposite sorbents for PAH removal was investigated.To achieve this, the sorbent underwent washing with methanol in triplicate to desorb PAHs from the sorbent surface.Subsequently, the sorbent was dried at 50°C for reuse.The results, as presented in Table 3, indicate that the sorbent can effectively remove PAHs through four adsorption-desorption cycles with minimal variance in R%.Experimental findings suggest that the sorbent maintains high adsorption capacity and magnetic retrievability even after cycles, underscoring its potential for repeated use in PAH remediation applications.

Comparison with other sorbents
As mentioned in the preceding sections, PAHs are significant environmental pollutants with adverse effects on human health 62 .Their presence has been documented in various food products, including milk, raising concerns due to its widespread consumption 12,63 .Various methods are available for eliminating PAHs from solid and liquid foods 64 .Among these approaches, the adsorption method shows promise as a cost-effective and environmentally friendly option 65 .In recent years, there has been growing interest in magnetic nanocompositebased sorbents due to their superparamagnetic properties, which enable magnetic field-assisted separation and enrichment 66 .The adsorption efficiency of the developed nanocomposites was compared to that of other magnetic nanocomposite sorbents, such as graphene nanosheets 67 , exfoliated graphene 68 , orange rind activated carbon

Conclusion
After synthesizing and characterizing a magnetic nanocomposite comprised of Cs/MoS 2 /Fe 3 O 4 , we successfully utilized it as an efficient sorbent for eliminating PAHs from milk.Through comprehensive characterization techniques including XRD, FTIR, FE-SEM, TEM, and VSM, we confirmed the successful coating of Cs onto the MoS 2 /Fe 3 O 4 nanocomposite.Various factors affecting the PAH adsorption process, such as nanocomposite dosage, initial PAH concentration, pH, and contact time were systematically investigated.Our findings revealed that the lowest and highest removal efficiencies were observed at nanocomposite doses of 0.01 g and 0.045 g, respectively.The optimal conditions for maximum PAH removal were identified as a pH of 6.0, a sorbent amount of 0.045 g, an initial PAH concentration of 150 mg/L, and a contact time of 150 min.Furthermore, the adsorption data for PAH removal using the prepared composite exhibited excellent agreement with the Freundlich isotherm model and the pseudo-second-order kinetics model, indicating a superior fit compared to the Langmuir isotherm model and the pseudo-first-order kinetics model.The procedure for removing PAHs utilizing the sorbent exhibits several notable strengths.Firstly, employing a magnetic chitosan/MoS 2 nanocomposite absorbent for PAH removal introduces a pioneering method, which holds promise for superior efficacy compared to conventional techniques.Additionally, integrating MoS 2 nanoparticles into the chitosan matrix has the potential to enhance adsorption properties due to the abundant surface area and functional groups inherent in MoS 2 .Moreover, the inclusion of magnetic nanoparticles enables effortless separation of the sorbent from the solution using an external magnetic field, streamlining the recovery process and reducing operational expenses.Furthermore, chitosan's biodegradability and environmental compatibility bolster the sustainability of the sorbent material.However, the procedure does have certain limitations.Chief among them is the scalability of the synthesis process for the magnetic chitosan/MoS 2 nanocomposite, which may pose challenges, particularly for large-scale applications, potentially impeding its industrial feasibility.Furthermore, while chitosan is regarded as environmentally benign, concerns arise regarding the potential release of MoS2 nanoparticles during the absorption process, necessitating comprehensive risk assessment studies to evaluate their long-term environmental impact and toxicity.

Figure 3 .
Figure 3. Effects of Cs/MoS 2 /Fe 3 O 4 nanocomposite dose (A), pH of the solution (B), initial PAHs concentration (C), and contact time (D) on percentage removal of phenanthrene, anthracene, and pyrene from milk.

Figure 5 .
Figure 5.The effect of contact time on PAH removal by the Cs/MoS 2 /Fe 3 O 4 nanocomposite according to the pseudo-first-order kinetic model (A), pseudo-second-order kinetic model (B), and intra-particle diffusion kinetic model (C).
displays the spherical and regular Fe 3 O 4 nanoparticles effectively loaded onto CS/MoS 2 , indicating the formation of the CS/MoS 2 /Fe 3 O 4 nanocomposite.The energy-dispersive X-ray spectroscopy (EDX) pattern of the CS/MoS 2 /Fe 3 O 4 nanocomposite is depicted in Fig.

Table 3 .
Comparison of the various sorbents for removing PAHs.Fe 3 O 4 -SiO 2 -2DMDPS, and Fe 3 O 4 -SiO 2 70 (Table3).The findings indicate that the sorbent demonstrates the highest adsorption capacity among the prepared sorbents for PAH removal.