Synthesis and characterization of commercial chitosan beads cross-linked with glutaraldehyde

Chitosan is a natural polymer with interesting properties for removing organic compounds. The present work deals with the preparation and characterization of chitosan beads using glutaraldehyde (GLA) as a crosslinking agent, to be applied in the future to remove organic compounds in aqueous matrices. The variation in the origin of the chitosan or in its conditions of obtaining can alter its physical-chemical properties, generating modifications in the characteristics of the beads, which often can make the results not reproducible. There is a great difficulty in comparing the results obtained with those in the literature, as there are a large number of differences in the physical and chemical properties of chitosan. Thus, the determination of these properties helps to clarify the different characteristics found for the beads, and which will influence their application. Initially, the physical-chemical analysis of the commercial chitosan used in the study was performed, since many national chitosan manufacturers do not specify the methodology for obtaining it, not even its processing conditions. The beads obtained from commercial chitosan were prepared using a drip system, after the crosslinking process with glutaraldehyde (GLA) (0.75% 2.5% and 25%) the samples were characterized by Transformed Infrared Spectroscopy Fourier (FTIR), X-Ray Fluorescence (FRX), X-Ray Diffraction (DRX) and Scanning Electron Microscopy (SEM). The crosslinking process promoted changes in the characteristics of the beads, changing their coloring characteristics, indicating the effectiveness of the crosslinking, which was confirmed through the XRD and SEM analysis, since there was an increase in crystallinity. With the FTIR it was possible to visualize the bonds formed between the functional groups of chitosan with GLA, which occurred preferentially in the amino groups. The preparation of the beads proved to be adequate, since it resulted in beads similar to that found in the literature. (author)