Surface Modifications of Superparamagnetic Iron Oxide Nanoparticles with Polyvinyl Alcohol and Activated Charcoal as Methylene Blue Adsorbents

Abstract

As novel methylene blue adsorbents, polyvinyl alcohol and activated charcoal were used to modify the surface of superparamagnetic iron oxide nanoparticles. The adsorption capacity after 69 h was 26.50 ± 0.99–40.21 ± 1.30 mg/g, depending on the temperature (333.15, 310.15, and 298.15 K) and the initial concentration of methylene blue, which was between 0.017 and 0.020 mg/mL. Based on thermodynamics parameters, the adsorption process can be considered to be spontaneous endothermic physisorption. Kinetics studies show that the pseudo-second-order model was the best-fitted model. Adsorption isotherm studies show that the best-fitted models were the Langmuir, Langmuir, and Temkin and Pyzhev isotherm models when adsorbing MB at 333.15, 310.15, and 298.15 K, respectively.

Surface Modifications of Superparamagnetic Iron Oxide Nanoparticles with Polyvinyl Alcohol, Chitosan, and Activated Carbon or Graphite as Methylene Blue Adsorbents—Comparative Study

“…To determine the classification of IONPs in the samples, XRD was used to determine the crystal structure as well as the crystallite size of the materials. According to the results shown in Figure 3, the peaks appeared at 2θ positions of 30.22°, 35.58°, 43.22°, 53.68°, 57.27°, and 62.85°, which are denoted as being correlated with the magnetite (based on the corresponding hkl indices), similar to previous publications [6,17,31]. It can be concluded that the IONPs presented in the materials were SPION, and the mixture of materials with SPION can be proved to be a successful blend according to the similar peaks shown in the diffractograms.…”

“…Similar to previous publications, using UV-VIS spectroscopy, Q t , %LC, and %EE were evaluated, as shown in Table 3 [6,17,31]. As shown in Table 3 and Figure 7a, the adsorption capacity of SPION/PVA/CS/AC after 310 h was 7.6 ± 0.2 mg/g, 14.9 ± 0.1 mg/g, and 22.4 ± 0.05 mg/g at MB concentrations of 0.015 mg/mL, 0.02 mg/mL, and 0.025 mg/mL, respectively.…”

“…The functional groups presented in nanoparticles and the structure of the adsorbents were determined by FTIR using the same method as in previous publications [6,17,31]. The two samples of SPION/PVA/CS/AC and SPION/PVA/CS/GR were analyzed by FTIR analysis, and the results are shown in Figure 4 and Table 1.…”

“…Nevertheless, several investigations have demonstrated that some undesired SPION aggregates may have lower stability, biocompatibility, and effectiveness. As a result, the use of SPION in conjunction with other stabilizing tools, such as carbon compounds, has been researched [6,10,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31].…”

“…Hence, the current work evaluates the potential for MB adsorption and desorption onto SPIONbased composites employing polymer blends and carbon-based materials. Therefore, the SPION/PVA/CS/AC and SPION/PVA/CS/GR were synthesized, and the MB adsorption/desorption capabilities were investigated and compared to the SPION/PVA/CS/GO, SPION/PVA/GR, and SPION/PVA/AC, which were previously published [6,17,31].…”