Straightforward Synthesis of Superparamagnetic Fe3O4-Carbon Dot Nanohybrids for Environmental Remediation: A Model Study Using Congo Red
- 1Universidade Federal de Minas Gerais , , Av. Antônio Carlos, 6627, Pampulha , ,
- 2Centro de Desenvolvimento da Tecnologia Nuclear , Av. Antônio Carlos, 6627, Pampulha , ,
- 3Universidade Federal de Ouro Preto , , Campus Morro do Cruzeiro, Rua Quatro, 786, Bauxita , ,
Abstract
Carbon dots (CDs) have attracted increasing interest as carbon-based nanomaterials due to their tunable surface chemistry, colloidal stability and low toxicity. Among them, magnetic carbon dots (MCDs) constitute a promising multifunctional subclass. In this work, magnetite-based magnetic carbon dots (Fe3O4-MCDs) were synthesized through a straightforward route using only ammonium ferric citrate and ethylenediamine as precursors. TEM revealed quasi-spherical Fe3O4-MCD nanohybrids with an average particle size of 12 ± 3 nm. XPS depth profiling employing Ar+ ion sputtering showed that these nanoparticles possess a magnetite-rich interior and a functionalized carbon-rich outer region. Furthermore, these nanoparticles self-assembled into hierarchical architectures with interparticle voids, resulting in a porous network with a specific surface area of 107 m2 g–1 and a pore volume of 0.431 cm3 g–1. In addition, the negligible coercivity and remanence are consistent with superparamagnetic-like behavior at room temperature, with a saturation magnetization of ∼60 emu g–1, facilitating rapid magnetic separation and redispersion. The Fe3O4-MCDs were evaluated for the adsorption of Congo red as a model pollutant, achieving an adsorption capacity of 121.6 mg g–1. Nonlinear kinetic analysis showed that adsorption followed the mixed 1,2-order model, while the Sips isotherm best described the equilibrium data. Overall, the results demonstrate that the Fe3O4-MCDs combine straightforward synthesis, high saturation magnetization, superparamagnetic behavior, and pollutant adsorption performance. These properties arise from their carbon/magnetite nanoarchitecture and engineered interfacial chemistry, promoting interactions with pollutants and highlighting their potential for multifunctional contaminant removal.
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BibTeX
@article{ferreira2026straightforward,
title = {{Straightforward Synthesis of Superparamagnetic Fe3O4-Carbon Dot Nanohybrids for Environmental Remediation: A Model Study Using Congo Red}},
author = {Arthur Hegermann Ferreira and Pedro Lana Gastelois and Leandro Vinícius Alves Gurgel and Fabiano Vargas Pereira},
journal = {ACS Omega},
year = {2026},
month = oct,
doi = {10.1021/acsomega.6c08673},
url = {https://pubs.acs.org/acsodf/article/doi/10.1021/acsomega.6c08673/5460307/Straightforward-Synthesis-of-Superparamagnetic},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Straightforward Synthesis of Superparamagnetic Fe3O4-Carbon Dot Nanohybrids for Environmental Remediation: A Model Study Using Congo Red
AU - Arthur Hegermann Ferreira
AU - Pedro Lana Gastelois
AU - Leandro Vinícius Alves Gurgel
AU - Fabiano Vargas Pereira
PY - 2026
DA - 2026/10/28
JO - ACS Omega
DO - 10.1021/acsomega.6c08673
UR - https://pubs.acs.org/acsodf/article/doi/10.1021/acsomega.6c08673/5460307/Straightforward-Synthesis-of-Superparamagnetic
AB - Carbon dots (CDs) have attracted increasing interest as carbon-based nanomaterials due to their tunable surface chemistry, colloidal stability and low toxicity. Among them, magnetic carbon dots (MCDs) constitute a promising multifunctional subclass. In this work, magnetite-based magnetic carbon dots (Fe3O4-MCDs) were synthesized through a straightforward route using only ammonium ferric citrate and ethylenediamine as precursors. TEM revealed quasi-spherical Fe3O4-MCD nanohybrids with an average particle size of 12 ± 3 nm. XPS depth profiling employing Ar+ ion sputtering showed that these nanoparticles possess a magnetite-rich interior and a functionalized carbon-rich outer region. Furthermore, these nanoparticles self-assembled into hierarchical architectures with interparticle voids, resulting in a porous network with a specific surface area of 107 m2 g–1 and a pore volume of 0.431 cm3 g–1. In addition, the negligible coercivity and remanence are consistent with superparamagnetic-like behavior at room temperature, with a saturation magnetization of ∼60 emu g–1, facilitating rapid magnetic separation and redispersion. The Fe3O4-MCDs were evaluated for the adsorption of Congo red as a model pollutant, achieving an adsorption capacity of 121.6 mg g–1. Nonlinear kinetic analysis showed that adsorption followed the mixed 1,2-order model, while the Sips isotherm best described the equilibrium data. Overall, the results demonstrate that the Fe3O4-MCDs combine straightforward synthesis, high saturation magnetization, superparamagnetic behavior, and pollutant adsorption performance. These properties arise from their carbon/magnetite nanoarchitecture and engineered interfacial chemistry, promoting interactions with pollutants and highlighting their potential for multifunctional contaminant removal.
SN - 2470-1343
ER -