Modificação e caracterização das fibras de Luffa cylindrica com nanoferritas de zinco

Abstract

Research in the field of composites has increased over the years due to the growing importance of developing advanced materials, highlighting unique properties and the significant advantages they offer compared to conventional ones. This study consisted of using vegetable sponge (Luffa cylindrica) modified with zinc ferrites, seeking an innovative approach to obtain complementary properties for natural fibers. The sponge was used in two ways: first, as fiber with only manual cutting, and after the grinding process, as powder. After that, the materials were treated in an alkaline medium to reduce the lignin and hemicellulose content and to create a rougher surface. Once treated, the vegetable sponge (fibers or powder) was used as a support for the synthesis of zinc ferrites by the coprecipitation method with sodium hydroxide. The synthesized material was analyzed by Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, transmission electron microscopy, and magnetic force testing. The results showed that the alkaline treatment was effective in reducing the lignin content, with a change in the 1735 cm-1 band corresponding to the C=O bond, and an increase in crystallinity by X-ray diffraction analysis. In this way, the zinc ferrites, on a nanometric scale, with an average diameter of less than 25 nm, were fixed on the sponge surface. The final material exhibited magnetic properties, relating to the strength and magnetic field, and synthesis yields of 85% and 65% for the powder and fiber samples, respectively. Thus, it is concluded that the synthesized composite, called Luffa cylindrica/ZnFe2O4, possesses properties of both the organic and inorganic phases, having the advantage of being synthesized in a quick and efficient manner. It also highlights the potential for application in a geopolymer, which can be used for biodiesel synthesis and catalysis, as well as acting as a photocatalytic agent in the degradation of effluent dyes or even as a substitute in cement composition. This study contributed to the expansion of knowledge in chemistry and materials science, more specifically, vegetable fibers with nanoferrites, providing a basis for future investigations and applications.