Magnetized styrene‐divinylbenzene resins can be obtained by inserting superparamagnetic nanoparticles of maghemite (γ‐Fe2O3) in the polymeric matrix. The incorporation of this nanoparticulate material can be influenced by several factors. The objective of this work was to evaluate the influence of these variables through an experimental design, where three factors were evaluated: cross‐linking degree, initiator content and porogenic agent, at two levels. Subsequently, to evaluate the properties of the synthesized magnetized resins, magnetization curves were plotted using a vibrating sample magnetometer, thermal stability of the magnetized copolymer was determined by thermogravimetric analysis and the morphology was observed by scanning electron microscopy. The highest initiator content produced the greatest synthesis yield, and the presence of toluene had a positive effect on saturation magnetization, indicating that incorporation of maghemite in the polymer matrix and thermal degradation were influenced by higher divinylbenzene content.

Nanopartículas de maghemita (γ-Fe2O3) vem sendo sintetizadas pela técnica de coprecipitação por hidrólise alcalina para magnetizar matrizes poliméricas. Neste trabalho foram sintetizadas nanopartículas de ferro caracterizadas por diferentes técnicas mostrando pelo seu tamanho de partícula que esse material apresentou propriedades superparamagnéticas.

Um grande problema ambiental é a geração de efluentes contaminados com metais tóxicos. Uma alternativa viável ao seu tratamento é a biossorção, como o uso da casca de coco verde. Este trabalho avaliou a capacidade de adsorção de íons de cobre (II) em solução aquosa, utilizando a casca do coco como adsorvente. Primeiramente, a casca foi tratada com água e com solução de NaOH 0,1 mol.L-1. Após o tratamento, foi colocada em contato com solução padrão de cobre II, onde se realizou um planejamento fatorial completo 23. Os melhores resultados foram obtidos pelo tratamento com NaOH.

Magnetized polymers are produced by incorporating magnetic particles in a polymeric matrix. This article describes the use of the suspension polymerization technique using ethyl acrylate and divinylbenzene as monomers, in the presence of heptane and/or toluene as diluent, initiated by free radicals. To produce the polymer, we first performed fractional factorial planning to help visualize the factors that could influence the results, to verify the action of different responses simultaneously. Five factors were evaluated that influence the production of the polymer and incorporation of iron in the matrix. Infrared spectroscopy, X-ray fluorescence, magnetic force testing and scanning electron microscopy were used to characterize the samples. The results indicated the positive influence of the quantity of the polymerization initiator on the yield of the process and the negative effect of the content of divinylbenzene on the incorporation of iron in the matrix and on the magnetic force.

Superparamagnetic nanoparticles such as magnetite (Fe3O4) and maghemite (γ-Fe2O3) have been used to produce magnetic nanocomposites with several polymeric matrices, such as magnetic styrene-divinylbenzene nanocomposites. Through the incorporation of these nanoparticles, the nanocomposite presents the phenomena of superparamagnetism, low coercivity and high magnetic susceptibility. Due to these features, magnetic nanomaterials can be removed from the place where they are inserted through an external magnetic field, thus differentiating them from conventional systems such as those used for treating oily water that require high costs of chemical agents for removal. These properties depend directly on the size distribution of the nanoparticles and on the presence or absence of interactions between the surface of the polymeric matrix and the contaminants. These materials have many applications and for this purpose the objective of this work is to present a bibliographic review and state-of-the-art of the evolution of magnetic styrene-divinylbenzene nanocomposites over the years. According to the reports in the literature, these systems are superior to those applied conventionally in the sectors of biotechnology, agriculture, oil/gas, and nuclear chemistry, mainly for the removal of toxic metals from aqueous media