Chitosan-coated magnetic nanoparticles (CMNP) were prepared in one-step by precipitation in a high-aqueous phase content reverse microemulsion in the presence of chitosan. The high-aqueous phase concentration led to productivities close to 0.49 g CMNP/100 g microemulsion; much higher than those characteristic of precipitation in reverse microemulsions for preparing magnetic nanoparticles. The obtained nanoparticles present a narrow particle size distribution with an average diameter of 4.5 nm; appearing to be formed of a single crystallite; furthermore they present superparamagnetism and high magnetization values; close to 49 emu/g. Characterization of CMNP suggests that chitosan is present as a non-homogeneous very thin layer; which explains the slight reduction in the magnetization value of CMNP in comparison with that of uncoated magnetic nanoparticles. The prepared nanoparticles show high heavy ion removal capability; as demonstrated by their use in the treatment of Pb 2+ aqueous solutions; from which lead ions were completely removed within 10 min.
control the fundamental structure and behavior of matter, reaching atomic and molecular levels. This domain offers the possibility to interpret new phenomena and create new properties presented in micro and nanoscopic scales. These characteristics might offer excellent and differentiated functions comparing to bulk materials. Nanoscale materials properties are strongly influenced by the surface (ratio area/volume), being equivalent or superior to volume effects. Changes in chemistry reaction, electric conductivity, enhancement of resistance, and loss of magnetic properties are observed when materials dimensions are < 100 nm. Potential areas for nanomaterials include areas like nanoelectronics, nanofiltration, and nanosensors [1][2][3][4][5].In the development of nanomaterials, polymeric fibers are in expansion in different knowledge areas. There are many techniques to synthesize polymeric fibers like wet spinning, dry spinning, melt spinning, gel spinning and, among others. Nowadays the most popular is electrospinning, which utilizes electrical forces to produce polymer fibers with diameters ranging from a few nanometers to several micrometers. However, a technique recently developed named solution blow spinning (SBS) was also succeeded [6-10]. Compared to electrospinning process, SBS does not use high voltage field, the production rate is several times higher with fiber diameters similar to those produced by electrospinning. The SBS apparatus is formed by a concentric nozzle, compressed air (nitrogen, argon or air), pressure measurer, a hypodermic syringe, a system of mechanical injection, and a rotator collector with controlled velocity, as shown in Fig. 1.In the SBS process, the solution is pumped through the inner nozzle with a fixed injection ratio. The concentric geometry of the nozzle favors the solution to adopt a conical shape at the end of the needle due to air flux which is responsible for dragging the fibers to the collector. Along with its way, the solvent can be wholly or partially evaporated, and Abstract The development of polymeric fibers incorporated with nickel (Ni) nanoparticles (NPs) has gained broad interest due to its applications, mainly for impurities removal from oil with the aid of magnetic field. In the present study, poly(vinylidene fluoride) (PVDF) fibers containing Ni NPs were produced by solution blow spinning (SBS) technique. Scanning electron microscope (SEM) measurements showed fibers with an average diameter of 564 nm, randomly dispersed without a preferred orientation. X-ray spectrum shows peaks related to Ni showing that Ni NPs were incorporated into the fibers. The magnetic analysis of the nanocomposite shows the hysteresis loops typical of ferromagnetic behavior and ZFC-FC curves revealed the presence of superparamagnetic behaviour and an average blocking temperature of 165 K. The results achieved in this work showed that is possible to produce fibrous material, using SBS technique, with unusual magnetic properties that may be applicable in various fields, including differe...
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