New modified chitosan composites and nanocomposites for different applications

Abstract

The present work focuses on the preparation of chitosan composite and chitosan nanocomposite derivatives for different applications. Chitosan was modified with bentonite or nano-bentonite to give chitosan composite and nanocomposite derivatives hydrogels I and II respectively, however chemical modification of chitosan with isonicotinic aldehyde via Schiff base formation in presence of bentonite or nanobentonite yielded chitosan composite and nanocomposite derivative hydrogels In and IIn respectively. The prepared hydrogels were characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (X-Ray), Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), Scanning electron microscopy (SEM), and swelling behavior. Adsorption studies for removal of heavy metal ions from aqueous media and the biological activity for the new hydrogels were studied. Results of evaluation of the prepared chitosan derivatives hydrogel for metal ions uptake showed that the maximum adsorption capacity amounted to 68 and 22 mg/l and the highest efficiency for adsorption of cobalt and mercuric ions from aqueous solution by hydrogel IIn at 10 h (93.2%) and (97.8%) respectively, whereas the adsorption capacity of hydrogel IIn increased with the increase of the initial concentration of heavy metals ions ranging from 0.4 to 1 g/l. However, modified chitosan derivative hydrogels In and IIn showed remarkable MIC and MBC towards Gram-positive (B. subtilis) (19.5, 38) μg/ml compared to the standard antibiotic Ciprofloxacin (19, 38) μg/ml respectively.

Keywords

• chitosan; isonicotinic aldehyde; bentonite; nano-bentonite.