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Official websites use. Share sensitive information only on official, secure websites. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. 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 pseudo-second-order kinetic model exhibited superior fitting to the experimental data, indicating an equilibrium time of approximately min. Moreover, the equilibrium adsorption process followed the Freundlich isotherm model, with k f and n values exceeding 7. Keywords: Adsorption removal, Chitosan, Milk sample, Molybdenum disulfide, Nanocomposite, Polycyclic aromatic hydrocarbons. Polycyclic aromatic hydrocarbons PAHs are characterized by the presence of two or more interconnected aromatic or benzene rings arranged in linear, angular, or cluster structures. They can occur naturally through processes such as forest fires and volcanic eruptions 1 , 2 , as well as being generated by environmental pollutants, incomplete combustion, and industrial processing 3. The presence of PAHs is a cause for concern due to their carcinogenic, mutagenic, and toxic properties, as well as their potential for long-range transport and adverse effects on human health 4. PAHs have been characterized as major pollutants possessing genotoxic characteristics and the potential to cause cancer, as classified by reputable international organizations 5 — 7. The main route of human exposure to PAHs is through food consumption, particularly when consuming contaminated food products. Once ingested, PAHs can become metabolically activated within cells, leading to the formation of diol-epoxides. These diol-epoxides can bind to macromolecules, including DNA, causing disruptions in replication and mutations. Ultimately, this process contributes to the development of a carcinogenic state 10 , Milk and dairy products are commonly consumed in human diets, especially by children and the elderly 12 , PAHs, being lipophilic, tend to accumulate in the food chain, particularly in high-fat foods 14 , Animal-derived products like milk are significant sources of PAH contamination. Ruminant milk, in particular, can contain elevated levels of PAHs due to the consumption of contaminated feed and grass in proximity to industrial areas, as well as the ingestion of contaminated soil. Therefore, effective approaches are urgently needed to reduce the concentration of PAHs, specifically phenanthrene, anthracene, and pyrene, in milk and dairy products. Adsorptive removal techniques provide numerous advantages for the removal of PAHs in food samples 16 — The selective and specific nature of these techniques ensures the targeted removal of PAH compounds, reducing the risk of contamination and protecting public health. Rapid and efficient removal, versatile application, non-toxicity, and cost-effectiveness further enhance the appeal of adsorptive removal methods 19 , By incorporating these techniques into milk processing and quality control, food safety can be enhanced, ensuring that milk products are free from PAH contaminants and providing consumers with safe and wholesome dairy products. The success and effectiveness of this technique heavily depend on the choice and performance of the sorbent material Sorbents play a crucial role in adsorptive removal processes by selectively attracting and retaining target contaminants 22 , Recently, nanomaterials and nanocomposites have gained attention as a potential solution for PAH removal 24 , The use of these materials as sorbents provides several benefits including versatility, cost reduction, high efficiency in removing contaminants, quick cleanup, and the possibility of regenerating and reusing the sorbent materials. This nanocomposite exhibits strong magnetic properties and has demonstrated a high adsorption capacity for various compounds from aqueous samples, such as N,N -diethylaniline, N,N -dimethylaniline, and aniline The synthesized sorbent is then utilized for the effective removal of carcinogenic PAH compounds, specifically phenanthrene, anthracene, and pyrene, from milk samples. Furthermore, we investigate the isotherm and kinetic of the adsorption process for these three PAHs on the developed sorbent. This sorbent is then employed for the efficient removal of carcinogenic PAH compounds, specifically targeting phenanthrene, anthracene, and pyrene, from milk samples. Additionally, we investigated the kinetics of PAH adsorption using the sorbent, elucidating the underlying mechanisms of the process. Furthermore, we examined the equilibrium adsorption behavior of PAHs utilizing both the Freundlich and Langmuir isotherm models, providing insights into the sorption process at equilibrium. Ultimately, the sorbent was employed to extract PAHs from spiked milk samples, serving as representative real food samples with complex matrices. This approach aimed to assess the sorbent's efficacy in removing PAHs from actual food samples under realistic conditions. A precise mixture of urea 8. The resulting product was then meticulously rinsed with deionized water and ethanol, respectively. 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. The resulting mixture was centrifuged at rpm for 15 min to separate the solution. After this, a solution of glutaraldehyde 5 mL; 2. The magnetic properties of the sorbent were investigated using a vibrating sample magnetometer from Lake Shore Cryotronics in the USA. Helium gas The temperature program involved three steps. These experiments were performed using an Erlenmeyer flask 50 mL , and various operational parameters were investigated. The contact time was fixed at range of 10 to min, and the experiments were conducted at room temperature. To prepare the samples, a milk sample of Then, 0. The adsorption process took place at room temperature with continuous shaking at rpm for min. After completing the adsorption of PAHs, the sorbent was completely separated from the spiked milk sample solution using a magnet. In the experiments on adsorption isotherms, a quantity of sorbent 0. The mixture was shaken at rpm for 3h. The adsorption data underwent adjustments through the utilization of Langmuir, Freundlich, Sips, and Dubinin- Adushkevich models The kinetic study was carried out using a spiked PAH solution 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 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. FTIR spectra were utilized to assess the chemical structures and functional groups of the sorbent. On the other hand, the CS spectrum Fig. Additionally, the wide peak at cm -1 was formed by the stretching vibration of hydroxyls in Fe 3 O 4 and CS 46 , The XRD pattern was used to examine the crystalline structure of the produced adsorbent. This observation aligns with a previous study The nanocomposite's morphology and size were analyzed using TEM. In Fig. Upon combining with MoS 2 , a distinct uniform core—shell structure is observed Fig. The layered structure of MoS 2 is evident, with individual layers discernible in bright and darker sections from the layer cross-section Additionally, the nanocomposite's morphology and surface uniformity were examined using FE-SEM images. As depicted in Fig. Furthermore, Fig. Langmuir A and Freundlich B sorption diagrams for pyrene, anthracene, and phenanthrene. This pattern reveals that the composite material consists of carbon, oxygen, iron, sulfur, nitrogen and molybdian elements, with weight percentages of Notably, carbon and molybdian exhibit the highest and lowest weight percentages within the sorbent structure. As illustrated in Fig. 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 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 , The results revealed a significant trend, where the adsorption efficiencies of the PAHs increased with increasing dosage of the nanocomposite from 0. 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. Therefore, based on these collective findings, a sorbent dosage of 0. The pH is an important parameter to consider when studying liquid-phase adsorption 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. 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. 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 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. The duration of contact between PAHs and the sorbent is a crucial factor that influences the efficiency of adsorption 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 min. As shown in Fig. This suggests that PAHs reached equilibrium on the sorbent's surface after min. Therefore, a contact time of min was chosen as the optimal value for further investigation. The Langmuir Eq. 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. 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 The n-values of 1. Additionally, the K F values exceeding 8. Also, these interactions are strong because K s are high. The maximum adsorption capacity q mS of the sorbent is in the range of 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 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. The linear forms of these model equations used in the kinetic study are outlined below 22 , 60 , 61 :. 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. 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. This suggests that the removal process is rapid with an equilibrium time under 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 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. 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. To achieve this, the sorbent underwent washing with methanol in triplicate to desorb PAHs from the sorbent surface. Experimental findings suggest that the sorbent maintains high adsorption capacity and magnetic retrievability even after multiple cycles, underscoring its potential for repeated use in PAH remediation applications. As mentioned in the preceding sections, PAHs are significant environmental pollutants with adverse effects on human health Their presence has been documented in various food products, including milk, raising concerns due to its widespread consumption 12 , Various methods are available for eliminating PAHs from solid and liquid foods Among these approaches, the adsorption method shows promise as a cost-effective and environmentally friendly option In recent years, there has been growing interest in magnetic nanocomposite-based sorbents due to their superparamagnetic properties, which enable magnetic field-assisted separation and enrichment 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 69 , Fe 3 O 4 -SiO 2 -2DMDPS, and Fe 3 O 4 -SiO 2 70 Table 3. The findings indicate that the sorbent demonstrates the highest adsorption capacity among the prepared sorbents for PAH removal. 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. The optimal conditions for maximum PAH removal were identified as a pH of 6. 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. 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. 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. The authors gratefully acknowledge the financial and technical support of the Neyshabur University of Medical Sciences, Neyshabur, Iran Grant number: The datasets used during the current study available from the corresponding author on reasonable request. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This section collects any data citations, data availability statements, or supplementary materials included in this article. As a library, NLM provides access to scientific literature. Sci Rep. Find articles by Alieh Rezagholizade-shirvan. Find articles by Mansoureh Mohammadi. Find articles by Yeganeh Mazaheri. Find articles by Saeid Fallahizadeh. Find articles by Haniyeh Ghorbani. Find articles by Samira Shokri. Find articles by Nabi Shariatifar. Find articles by Majid Darroudi. Find articles by Ehsan Shamloo. Received Feb 3; Accepted Jun 26; Collection date Open in a new tab. Publisher's note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Similar articles. Add to Collections. Create a new collection. Add to an existing collection. Choose a collection Unable to load your collection due to an error Please try again. Add Cancel.

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