RESUMEN
The preparation of Co-doped magnetite ferrofluids from natural sand was developed using a double-layer technique. The Co-doped magnetite nanoparticles formed a spinel phase with lattice parameters in the range of 8.355-8.422 Å and tended to agglomerate with the particle sizes of 7-12 nm. The presence of the first and second layers from oleic acid and DMSO was detected by the infrared spectrum as well as the olive oil used as a carrier liquid. The saturation magnetization of the superparamagnetic samples decreased from 24.4 to 4.8 emu/g with decreasing Co2+ composition. The particle size and electrostatic forces between the magnetic particles and the microbes played an essential role in inhibiting microbial growth. Interestingly, the increasing Co2+ composition enhanced the superior performance of the ferrofluids against E. coli, S. aureus, B. subtilis, and C. albicans. With additional extensive investigation, we believe that the prepared Co-doped magnetite double-layered ferrofluids from natural sand with superior antimicrobial performance can be new significant antimicrobial agents.
RESUMEN
Mn1-x Zn x Fe2O4 ferrofluids were produced from natural sand for magnetic sensors and radar absorbing materials. The X-ray diffraction data showed that the Zn partially substituted the Mn and Fe ions to construct a spinel structure. The increasing Zn composition decreased the lattice parameters of the structure. The transmission electron microscopy images showed that the filler Mn1-x Zn x Fe2O4 nanoparticles tended to agglomerate in three dimensions. Lognormal and mass fractal models were used to fit the small-angle X-ray scattering data of the ferrofluids demonstrated that the ferrofluids formed chain-like structures with a fractal dimension of 1.12-1.67 that was constructed from primary particles with sizes of 3.6-4.1 nm. The filler, surfactant, and carrier liquid of the ferrofluids were confirmed by the functional groups of the metal oxides, tetramethylammonium hydroxide, and H2O, respectively. The secondary particles contributed to the saturation magnetization of the Mn1-x Zn x Fe2O4 ferrofluids. The Mn1-x Zn x Fe2O4 ferrofluids demonstrated excellent performance as magnetic sensors with high stability, especially compared with MnFe2O4 ferrofluids. Furthermore, the ferrofluids exhibited excellent radar absorbing materials. The Mn1-x Zn x Fe2O4 ferrofluids prepared in this work may serve as a future platform for advancing magnetic sensors and radar absorbing materials.
RESUMEN
To date, the search for creating stable ferrofluids with excellent properties for biomedical application is one of the challenging scientific and practical investigations. In this study, novel Fe3O4/Ag nanohybrid ferrofluids from iron sand were synthesized using a double-layer method. The Fe3O4/Ag nanocomposites exhibited stable crystallite sizes of 11.8 12.1 nm and 36.8-37.2 nm for Fe3O4 and Ag, respectively. The lattice parameters of the spinel structure Fe3O4 and face-centered cubic Ag were respectively 8.344 Å and 4.091 Å. With increasing Ag amount, the crystallite phase of Ag in the nanocomposites increased from 40.2% to 77.2%. The XPS results confirmed that Fe3O4/Ag nanocomposites were successfully prepared, where Fe3O4 mixed well with Ag via strong ionic bonding. The FTIR results confirmed the presence of Fe3O4/Ag, oleic acid, and dimethyl sulfoxide as the filler, first layer, and second layer, respectively. The as-prepared ferrofluids exhibited superparamagnetic behavior, where the saturation magnetization decreased with increasing Ag content. The Fe3O4/Ag nanohybrid ferrofluids exhibited excellent antimicrobial performance against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Candida albicans. More importantly, the Fe3O4/Ag nanohybrid ferrofluids decreased the progression of liver fibrosis-related inflammation and fibrogenic activity on hepatic stellate cells.
