نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه شیمی، دانشکده علوم، دانشگاه گلستان، گرگان
2 گروه شیمی، دانشکده علوم، دانشگاه گلستان، گرگان، ایران
3 گروه فیزیک، دانشکده علوم، دانشگاه گلستان، گرگان، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Colors are one of the major environmental pollutants that lead to ecological problems. Methylene blue cationic dye with a complex aromatic structure is one of the most common dyes for coloring silk, cotton, and wool. In this study, CuFe2O4/PVP nanocomposite was synthesized as an adsorbent for the adsorption of methylene blue from aqueous solutions and was characterized using IR, XRD, and SEM techniques. The study also examined the effects of pH, contact time, and adsorbent mass on the dye's adsorption efficiency. The maximum adsorption efficiency of methylene blue was achieved at a pH of 12, with a contact time of 90 minutes and an adsorbent mass of 1 gram, resulting in an efficiency of approximately 65%. Kinetic studies of the adsorption process were also conducted by applying two models. Kinetic studies demonstrated that the adsorption of methylene blue onto the CuFe₂O₄/PVP nanocomposite conformed well to a pseudo-second-order kinetic model. Density functional theory (DFT) simulations explored methylene blue's interactions and potential adsorption of methylene blue onto the adsorbent. DFT simulations confirmed the stability of methylene blue adsorption on the nanocomposite surface, with binding energies ranging from 0.831 to 0.971 eV. The adsorption of methylene blue also reduced the energy gap, indicating easier electron transmission.
کلیدواژه‌ها [English]
EXTENDED ABSTRACT
Organic dyes pose significant environmental and health risks due to their toxic, mutagenic, and carcinogenic properties. Among these, methylene blue, a cationic dye with a complex aromatic structure, is widely used in the textile industry to color silk, cotton, and wool. This study focuses on synthesizing a CuFe₂O₄/PVP nanocomposite as an adsorbent for removing methylene blue from aqueous solutions. The nanocomposite was characterized using infrared spectroscopy (IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The study also examined the effects of pH, contact time, and adsorbent mass on the dye's adsorption efficiency. Kinetic studies of the adsorption process were also conducted by applying two models. Density functional theory (DFT) simulations explored methylene blue's interactions and potential adsorption of methylene blue onto the adsorbent.
All chemicals used were of analytical grade. The CuFe₂O₄/PVP nanocomposite adsorbent was synthesized through a multi-step process and characterized using IR, XRD, and SEM techniques. Adsorption experiments were conducted by agitating the adsorbent in 100 mL of a 10 M methylene blue solution in a 250 mL conical flask. After reaching equilibrium, the adsorbent was separated from the solution, and the residual concentration of methylene blue was measured using UV-Vis spectroscopy at a wavelength of 668 nm. Theoretical studies involved optimizing the CuFe₂O₄/PVP nanocomposite and methylene blue structures using DFT with the DMol³ calculation program, followed by adsorption studies.
The maximum adsorption efficiency of methylene blue was achieved at a pH of 12, with a contact time of 90 minutes and an adsorbent mass of 1 gram, resulting in an efficiency of approximately 65%. FT-IR spectra identified several important functional groups on the adsorbent surface that facilitate chemical bonding between the surface and the dye. The adsorbent exhibited well-defined IR bands at 575.17 cm⁻¹ and 450.05 cm⁻¹, corresponding to the Fe–O stretch in octahedral groups and the Cu–O stretch in tetrahedral groups. XRD analysis revealed sharp peaks indicative of well-crystallized materials. The SEM image showed that the nanocomposite particles were spherical and highly condensed, with sizes ranging from 42.55 to 53.30 nm. Kinetic studies demonstrated that the adsorption of methylene blue onto the CuFe₂O₄/PVP nanocomposite conformed well to a pseudo-second-order kinetic model. DFT simulations confirmed the stability of methylene blue adsorption on the nanocomposite surface, with binding energies ranging from 0.831 to 0.971 eV. The adsorption of methylene blue also reduced the energy gap, indicating easier electron transmission.
The CuFe₂O₄/PVP nanocomposite demonstrated optimal conditions for methylene blue removal at a pH of 12, with 1 gram of adsorbent and a contact time of 90 minutes, achieving an adsorption efficiency of approximately 65% and an adsorption capacity of 3.8 mg/g. The adsorption process altered the electronic properties of the nanocomposite, reducing the energy gap and increasing conductivity. The theoretical and experimental findings suggest that the CuFe₂O₄/PVP nanocomposite is a suitable adsorbent for methylene blue adsorption.
All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.
If the study did not report any data, you might add “Not applicable” here.
The authors would like to thank all participants of the present study.
The authors avoided data fabrication, falsification, plagiarism, and misconduct.
The author declares no conflict of interest.
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