Modification of Cotton Fibers with Magnetite and Magnetic Core‐Shell Mesoporous Silica Nanoparticles

Abstract

Magnetite (Fe3O4) and magnetic core‐shell mesoporous silica (Fe3O4‐mSiO2) nanoparticles are employed to coat cotton fibers using a room temperature water‐based direct electrostatic assembly method with polyelectrolytes. Core‐shell nanoparticles are fabricated by coating super‐paramagnetic magnetite clusters with a mesoporous silica layer (mSiO2) using a surfactant‐templating approach. The Fe3O4 clusters are initially synthesized by a co‐precipitation process. The cotton fibers are modified through a layer‐by‐layer technique using dipping cycles with PDDA and PSS polyelectrolytes solutions to enable further nanoparticles attachment. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images provides morphologic information of the synthesized nanoparticles and the modified cotton fibers. Composition and physicochemical properties are studied by powder XRD, FTIR, and SEM‐EDX methods, and thermogravimetric analysis (TGA) are carried out to determine the amount of nanoparticles adsorbed onto cotton samples. The saturation magnetization (MS) of nanoparticles determined by a vibrating sample magnetometer (VSM) is greater than that of the cotton‐nanoparticles nano‐composites. Potential applications of these composite materials can include protective clothing and transdermal drug delivery systems.

Activated Carbon from Yam Peels Modified with Fe3O4 for Removal of 2,4-Dichlorophenoxyacetic Acid in Aqueous Solution

“…The XRD patterns of the Fe3O4 nanoparticles, AC, and MAC are shown in Figure 2a. In accordance with the standard card JCPDS No.65-3107, the pattern for Fe3O4 nanoparticles showed the characteristic peaks at 30.2, 35.7, 43.1, 53.8, 57.2, and 62.9° which correspond to the (220), (311), (400), (422), (511), and (440) crystal planes, associated with a cubic structure [26,27,40].…”

“…Distilled water was used in all experiments. [26,27]. In a typical experiment, 4.86 g FeCl 3 •6H 2 O and 1.79 g FeCl 2 •4H 2 O were dissolved in 50 mL of distilled water, separately.…”

Synthesis of FeO@SiO2–DNA core–shell engineered nanostructures for rapid adsorption of heavy metals in aqueous solutions

“…The agglomeration was reduced due to the decrease in the dipolar-dipolar interaction between nanoparticles, which was promoted by the citric acid coating of FeO-NPs with a layer thickness of 2.2 AE 0.2 nm. 44 Although some agglomerates are observed, the nanoparticles can be easily dispersed due to the strong affinity of the carboxylic acid with the aqueous mediums. The hydrophilic nature of the carboxylic acid promotes a hydration effect in the water, leading the stabilization and good dispersion of FeO/ca-NPs.…”

“…The decrease of the magnetic response was also ascribed to a particle size reduction, 50 since the citric acid coating promoted a good dispersion of FeO/ca-NPs by breaking the dipolar-dipolar interactions of spins and reducing their coordination. 44 Additionally, the inset in Fig. 5 shows a low exchange bias (H EB ) and coercive (H C ) elds, which were calculated according to eqn (9) and (10).…”

“…The magnetic core can be easily coated with a SiO 2 shell (FeO@SiO 2 ) using a facile and inexpensive Stöber method. 25 The presence of silanol (Si-OH) and siloxane (Si-O-Si) groups on the SiO 2 shell promote few agglomerates of FeO@SiO 2 due to the formation of hydrogen bonds. 26 However, these groups also provide a large number of active sites for further functionalization with other molecules, and even for an improved adsorption process.…”