Journal of Applied Research in Chemical-Polymer Engineering

Abstract Research subject: In this study, Fe₃O₄ nanoparticles were first synthesized through a controlled co-precipitation method. Subsequently, a uniform silica coating was formed on the surface of iron oxide nanoparticles via the Stöber process using tetraethyl orthosilicate (TEOS) as the silica precursor, resulting in core–shell Fe₃O₄@SiO₂ nanoparticles with a stable and well-organized structure. The obtained nanoparticles were then functionalized with a molecularly imprinted polymer (MIP) to produce a targeted and selective adsorbent for the removal of zinc ions (Zn²⁺) from aqueous solutions. The concentration of Zn²⁺ ions was determined using Inductively Coupled Plasma (ICP) analysis.
Research approach: To comprehensively investigate the physical, chemical, and structural characteristics of the synthesized nanoadsorbent, various analytical techniques were employed, including transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR).
Main results: The characterization results confirmed the formation of a coherent structure with uniform particle size distribution, good thermal stability and successful incorporation of active functional groups on the nanoparticle surface. The adsorption performance of the nanoadsorbent for Zn²⁺ ions was evaluated by studying the effects of various operational parameters, including adsorbent dosage, contact time, pH and initial metal ion concentration. Optimized results revealed that under the conditions of an adsorbent dosage of 16 mg, pH=7, an initial concentration of 0.45 mmol L⁻¹, a solution volume of 50 mL, and a contact time of 21 min, the removal efficiency of Zn²⁺ ions reached 96%, indicating the high performance of the adsorbent (107.55 mg/g). Also, isotherm studies demonstrated that the adsorption process followed the Langmuir model, suggesting a monolayer adsorption mechanism. Furthermore, kinetic analysis showed that the experimental data fitted the pseudo-second-order model, confirming that chemisorption was the dominant rate-controlling mechanism. In addition, the synthesized nanoadsorbent exhibited excellent magnetic separability, allowing for easy recovery from the aqueous solution. It also demonstrated high reusability over multiple adsorption-desorption cycles without significant loss in its adsorption performance. Therefore, the designed adsorbent can be considered a stable, efficient, and environmentally friendly system, offering a promising approach for the effective treatment of industrial wastewater containing heavy metal ions.

Abstract Research subject: In this study, glucosamine-functionalized core–shell nanoparticles were synthesized. Subsequently, the nanoparticle synthesis was confirmed using various characterization techniques, and the synthesized nanoparticles were applied for heavy metal separation. To this end, Fe₃O₄@SiO₂ magnetic core–shell nanoparticles were synthesized via co-precipitation and Stöber methods. The core–shell nanoparticles were subsequently functionalized with cyanuric chloride and glucosamine. Glucosamine-functionalized nanoparticles were used as effective adsorbents for the removal of cadmium ions from aqueous solutions via solid-phase extraction.

Research approach: Morphological, structural, and magnetic properties, as well as particle size of the nanoparticles during synthesis, were investigated using transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), and X-ray diffraction (XRD). Additional analyses included Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), and vibrating sample magnetometry (VSM). Subsequently, the effects of various parameters—including adsorbent dosage, contact time, and solution pH—on adsorption performance were investigated.
Main results: The results indicated that the maximum cadmium adsorption capacity (145 mg/g) was achieved when 15 mg of adsorbent was added to 50 mL of solution with an initial concentration of 0.4 mmol/L over 18 minutes at pH 7. In addition, the synthetic nanoadsorbent was recycled and reused for six consecutive adsorption–desorption cycles using a magnet, without significant loss in adsorption performance. Glucosamine-functionalized core–shell nanoparticles are proposed as a promising technology for water and wastewater treatment, owing to their high adsorption capacity and reusability in sequential adsorption–desorption cycles.

Abstract Research subject: Poly (2-oxazoline) (PEOX) polymers are a family of synthetic macromolecules with biodegradable and biocompatible features. They resemble polypeptides in structure and therefore, have recently taken put to use in drug delivery. Nonetheless, these polymers suffer from relatively low thermal and mechanical performance and thus are reinforced with nanoparticles as nanocomposites. The molecular details of the reinforcement mechanism of PEOX have not yet been elucidated.
Research approach: This research work was done to reach an understanding on interaction of 2-oxazoline-based polymers with 2D nanoscale reinforcements and to shed light on the mechanism of reinforcing the respective nanocomposites. To this end, conformation and dynamics of poly (2-ethyl-2-oxazoline), as a known representative member of this family, near a functionalized graphene nanosheet were studied via classical molecular dynamics for a period of 10 ns. The effects of various temperatures and polymer chain lengths on polymer conformation and dynamics were assessed.
Main results: Molecular dynamics snapshots exhibited effective interaction of the polymer chain with the graphene nanosheet leading to adsorption, whereby conformation and dynamics of the chain underwent transition. The adsorbed polymer chain adopted a flat, folded arrangement parallel with the graphene plane. Also, the gyration radius was found to increase, when the polymer chain approached the graphene nanosheet. Pair correlation function curves revealed that the adsorption correlation length was on the order of the repeating unit end-to-end distance. Mean-square-displacement of the polymer chain decreased as it moved towards graphene. An increase in temperature led to a change in structure and dynamics of the adsorbed polymer chain.

Abstract Research subject: One of the major problems we face with the growth of various industries around the world is the environmental pollution of heavy metals. One of the most toxic heavy metals that is problematic even at low concentrations is Cr (IV).
Research approach: In this study, the removal of this toxic heavy metal was investigated with high efficiency by UIO-66-MnFe2O4-TiO2 magnetic adsorbent. For this purpose, magnetic nanocomposite (UIO-66-MnFe2O4-TiO2) was synthesized based on metal-organic framework (MOF) for adsorption of Cr (IV). The choice of the hydrothermal method for the synthesis of UIO-66 in addition to its simplicity resulted in the production of pure and efficient UIO-66, which produced very high efficiency during the experiments. MnFe₂O₄ nanoparticles were used to magnetize the adsorbent. To increase the magnetic properties and increase the loading efficiency of the MnFe₂O₄ nanoparticles, TiO₂ nanoparticles were used to increase the loading rate on the adsorbent. XRD, SEM, FT-IR, BET, VSM and EDX tests were used to the characterization of the adsorbent properties.
Main results: Effect of four effective variables during adsorption experiments such as adsorbent content (0.05 to 0.25 g), pH (2 to 6), adsorption time (15 to 75 min), initial metal ion concentration (200 to 1000 mg / l) at five levels (+2 to +2) were investigated using experimental design with response surface methodology (RSM) and central composite design (CCD). The best conditions were determined for the independent variables for the initial metal concentration of 552 mg /l. The optimum pH was obtained 4 during the experiment. Finally, the optimum values were achieved for adsorption parameters such as adsorption time and adsorbent amount were 42.3 min and 0.143 gr, respectively, and also the maximum adsorption rate was obtained 98%. Investigation of the adsorption isotherm kinetics showed that the pseudo-second-order model and Langmuir isotherm fit the Cr (IV) data well. After the adsorption process, the adsorbent can be removed from the environment by a magnetic field.

Abstract Research subject:
Zinc is one of the most dangerous organic components in industrial wastewaters, which pollutes the environment as a result of human activities and various industrial operations. In the present study, the adsorbent prepared from Gracilaria Corticata algae was used for the first time to recover and remove heavy metal zinc and equilibrium study of the process were done.
Research approach:
In the current work, the effect of important parameters such as initial pH of solution, adsorbent dosage and contact time were investigated on the adsorption efficiency of the process. Additionally, Langmuir and Freundlich two-parameter adsorption isotherm models were used to model the equilibrium of zinc adsorption.
Main results:
The results showed that according to the calculated correlation coefficient, Freundlich isotherm was better than the Langmuir in fitting the experimental data. The highest point-to-point correlation coefficient for adsorbent percentage was achieved at 3 g/ml adsorbent dosage with contact time of min 360 and pH=7 and the lowest one was at 4 g/ml adsorbent dose with contact time of min PH=360 and 7. However, the highest adsorption rate was observed for the adsorbent dosage of 4 g/ml with contact time of 420 min at pH=9 and the lowest adsorption percentage was achieved at the adsorbent dosage of 2 g/ml with contact time of 300 min and pH=5. The maximum and minimum adsorption percentages were 76.88 mg/g and 49.25 mg/g, respectively

Abstract Research Subject: In this paper, the adsorbents used to remove lead ion using adsorption operation have been reviewed.
Research Approach: The types of adsorbents used to remove lead ions, the modifications of adsorbents, adsorption conditions, isotherms and adsorption capacity of adsorbents have been investigated and compared based on the literature survey.
Main Results: Modification by impregnation of functional groups has a significant role in increasing the adsorption capacity. The pH of the solution plays an important role in the adsorption of lead ions and generally the adsorption capacity increases by increasing the pH of the solution. Langmuir's isotherm model has been more consistent with the equilibrium data. Among the reviewed adsorbents, carbon-based adsorbents such as activated carbon and graphen-oxide, modified by chemicals such as ammonium persulfate or polyamines, show higher adsorption. Also, biomasses due to their abundance and low prices have the potential to be used as lead ion adsorbents.